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Survivorship and Radiological Analysis of a Monoblock, Hydroxyapatite Coated Titanium Stem in Revision Hip Arthroplasty
Journal Pre-proof Survivorship and Radiological Analysis of a Monoblock, Hydroxyapatite Coated Titanium Stem in Revision Hip Arthroplasty Paul Saunders, Debbie Shaw, Sijin Sidharthan, P. Siney, Stephen K. Young, Tim Board PII:
S0883-5403(20)30118-2
DOI:
https://doi.org/10.1016/j.arth.2020.01.081
Reference:
YARTH 57789
To appear in:
The Journal of Arthroplasty
Received Date: 22 November 2019 Revised Date:
17 January 2020
Accepted Date: 30 January 2020
Please cite this article as: Saunders P, Shaw D, Sidharthan S, Siney P, Young SK, Board T, Survivorship and Radiological Analysis of a Monoblock, Hydroxyapatite Coated Titanium Stem in Revision Hip Arthroplasty, The Journal of Arthroplasty (2020), doi: https://doi.org/10.1016/ j.arth.2020.01.081. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2020 Elsevier Inc. All rights reserved.
Title: Survivorship and Radiological Analysis of a Monoblock, Hydroxyapatite Coated Titanium Stem in Revision Hip Arthroplasty Paul Saunders1, Debbie Shaw2, Sijin Sidharthan2, P Siney2, Stephen K Young1, Tim Board2 1. Department of Orthopaedics, Warwick Hospital, South Warwickshire NHS foundation Trust, Warwick, CV34 5BW, United Kingdom 2. Wrightington Centre for Hip Surgery, Wrightington Hospital, Hall Lane, Appley Bridge, Wigan, WN6 9EP, United Kingdom
Please address all correspondence to: Paul Saunders Department of Orthopaedics Warwick Hospital South Warwickshire NHS foundation Trust Warwick CV34 5BW United Kingdom [email protected]
1
Title: Survivorship and Radiological Analysis of a Monoblock, Hydroxyapatite Coated
2
Titanium Stem in Revision Hip Arthroplasty
3
Abstract
4
Aims: We evaluated the survivorship, incidence of complications, radiological subsidence, proximal
5
stress-shielding and patient reported outcomes of a conservative, monoblock, HA coated femoral
6
stem.
7
Methods: This retrospective cohort study reports on 254 revision hip arthroplasties between
8
January 2006 and June 2016. The mean age of patients was 71 years. The mean length of follow-
9
up was 62 months (range 12-152 months).
10
Results: There were 13 stem re-revisions; infection (4), periprosthetic fracture (4), aseptic stem
11
loosening (3), stem fracture (1), and ETO non-union (1). Kaplan-Meier aseptic stem survivorship
12
was 97.33% (CI 94-100) at 6 years. There were 29 intraoperative fractures. There were 6 cases of
13
subsidence greater than 10mm however none required revision. Ninety-six percent of cases
14
showed no proximal stress shielding. Thigh pain was reported in 3% of cases.
15
Conclusion: This study confirms that this stem provides good survivorship at 6 years, acceptable
16
complication rates, excellent proximal bone loading, low incidences of thigh pain and reliable clinical
17
performance in revision hip arthroplasty.
18
Word count: 161
19
Key message:
20
A monoblock, fully hydroxyapatite coated titanium stem is reliable in revision arthroplasty with mild-
21
moderate femur deficiencies.
1
22
Introduction
23
Since the start of the 21st century there has been a steady increase in the number of total hip
24
arthroplasties performed globally [1 ,2]. This demand is projected to continue to increase by 134%
25
for primary and 31% for revision hip surgery in the UK over the next two decades [2]. National (UK)
26
database reported hip re-revision rates are 9.09% at 5 years and 14.40% at 10 years [3]. National
27
databases provide case numbers for large scale survivorship analysis. Their reliability at a unit level
28
however has been questioned with a recent review published in 2019 stating that 10% of revision
29
cases performed in the UK were not captured; this equates to 800 revision cases per year not
30
considered in survivorship statistics [4, 5].
31
Data from worldwide arthroplasty registers indicate that the most common indications for hip
32
revision are aseptic loosening, dislocation, pain, septic loosening and periprosthetic fracture; the
33
ranking of indications varies by country [3, 6-7]. Aseptic loosening is associated with bone loss at
34
the metaphysis and diaphysis [8]. This loss of proximal structural support makes revision
35
arthroplasty a complex challenge. The traditional approach is to by-pass the depleted proximal bone
36
stock and achieve distal fixation using an appropriately designed stem. Distal loading of bone
37
however has been shown to result in proximal bone stress shielding (based on Wolff’s law of
38
remodelling) and higher incidences of mid-thigh pain [9-11]. Loss of proximal bone is evident from
39
two years post-surgery and ultimately makes subsequent attempts at revision surgery more
40
technically challenging with a greater risk of complications [12]. An alternative philosophy to distal
41
fixation is referred to as ‘conservative revision’. It uses a ‘top-down’ approach, aiming to achieve
42
fixation “as proximal as possible and as distal as necessary” [13]. This approach relies on a stem
43
design that maximally loads the remaining proximal bone [13-14].
44
The primary aim of this study was to determine the survivorship and incidence of intra- and post-
45
operative complications with a monoblock, fully hydroxyapatite (HA) coated femoral stem in revision
46
hip arthroplasty (single stem design). The secondary aim was to evaluate the conservative
2
47
approach rationale of proximal bone loading, reduced thigh pain and provision of bone stock in
48
cases of re-revision.
49
3
50
Method
51
A retrospective cohort study was conducted utilizing data from two high volume hip units in
52
the United Kingdom. Between January 2006 and June 2016, 272 femoral stem revisions (262
53
patients) were performed using a long, tapered, monoblock, HA coated, titanium stem (Corail®
54
Revision Stem, DePuy, Leeds, UK; previously named the KAR™). The revision stem is based on
55
the principles of the established primary stem (CORAIL®, DePuy, Leeds, UK), which has a
56
survivorship for stem revision of 93.6% at 30 years [15]. The revision stem has the same proximal
57
shape as the primary stem however it is 40 mm longer and has coronal and sagittal slots in the
58
extended distal portion to give the stem the flexibility to accommodate to the shape of femur and
59
avoid distal load transfer (Figure 1). It is indicated in revision hip arthroplasty with Paprosky types I,
60
II and IIIa femoral bone deficiencies, which make up approximately 89% of femur presentations in
61
revision arthroplasty [10].
62
There were 254 (93%) cases in 244 patients with a minimum one-year follow-up. There were
63
134 male and 110 female patients with a mean age at surgery of 71 years (range 46 – 96 years).
64
The mean length of radiological follow-up was 62 months (range 12-152). Thirty-seven percent of
65
cohort was over 75 years at the time of surgery. Sixty-seven (26%) patients died during the follow-
66
up period at a mean of 69 months post-surgery (range 16 – 133). At 5 years 134 cases had
67
radiological follow-up (52% of original cohort).
68
Indications for revision, type of primary procedure, classifications of femoral bone loss
69
(graded on the pre-operative x-ray; Paprosky Classification) [10] and the number of stem sizes used
70
at revision are presented in Table 1. In 2012, additional sized stems (sizes 11, 13 and 15) and a
71
high off-set version (7mm of lateralization) were introduced to expand the available range. Twelve
72
(5%) of the stems used were the high off-set version.
73
Surgeries were performed by the senior authors at each unit (SKY & TB) in 55% of cases,
74
with the remaining performed by 8 consultant surgeons across the two units. Posterior and lateral
75
surgical approaches were used and post-operatively patients were either permitted full or partial
76
weight-bearing for up to six weeks; dependent on specific surgeon/patient factors. Follow-up
77
evaluation of each patient was routinely scheduled at 6 weeks, 1, 5 and 10 years post-operatively. 4
78
The protocol for the study was approved by the local Trusts Research and Development
79
departments.
80
Data Extraction & Analysis
81
Local clinical records, radiographs, NHS Spine and unit level National Joint Registry (NJR)
82
data were analysed. Intraoperative complications were identified via radiographs and operation
83
notes. The occurrence of thigh pain was determined from follow-up clinic letters. Kaplan-Meier
84
survival data were used to construct the survival probabilities of implants, with 95% confidence
85
interval (CI). Patients’ functional outcomes were assessed using the Oxford Hip Score recorded at
86
6-18 months post-surgery [16].
87
Radiographic analysis was completed using the PACS system (Insight PACS, Insignia
88
Medical Systems, U.K) by two lead investigators (PS & DS). Radiographs were standardized for
89
magnification by using the calibration ball or, if not available, by measuring the known diameter of
90
the prosthetic head. Subsidence was calculated as the difference in stem height between the
91
immediate post-operative and one-year radiograph; using the method described by Engh & Masin
92
[17]. This method measures the change in vertical distance from the superior tip of the greater
93
trochanter to the shoulder of the prosthesis. The distance measured was grouped accordingly; ≤ 5
94
mm, 5–10 mm or > 10 mm. Greater than 5 mm was considered to indicate stem subsidence. The
95
Kappa coefficient for subsidence grouping was calculated as 1.0 for inter- and intra-rater reliability;
96
indicating a high level of agreement. Assessment of bone remodelling was conducted from the most
97
recent available x-ray; a minimum follow-up period of 2 years was required for cases included in this
98
analysis. Proximal bone remodelling was recorded as proximal stress shielding, no change or
99
proximal bone regeneration.
100
5
101
Results
102
Survivorship:
103
Of the 254 procedures with adequate follow up, 21 required re-revision. Eight cases did not
104
involve revision of the stem; five involving revision of the acetabular component only (four for
105
aseptic loosening and one due to recurrent dislocations) and 3 with insertion of a constrained liner
106
only due to dislocation. There were thirteen re-revisions involving removal of the femoral stem;
107
details of patient demographics, prosthesis and re-revision procedure are shown in Table 2. The
108
Kaplan-Meier survivorship with the end point as any revision was 93.97% (CI 90-98) at six years
109
(Figure 2a). Survivorship with the end point as aseptic stem revision was 97.33% (CI 94-100) at 6
110
years (Figure 2b).
111
Complications:
112
Thirty-one surgeries involved an extended trochanteric osteotomy (ETO), with one
113
case resulting in failed union and the development of complications leading to revision. In addition
114
to the four revised dislocated cases there were six dislocations in individual patients managed with
115
manipulation under anaesthetic. Dislocations occurred at a mean 33 months post-surgery with five
116
(50%) occurring within the first year. There were 29 (11%) intraoperative fractures managed with
117
cerclage wiring in all but one case. None of these fractures resulted in further complications. In the
118
case without wiring a non-displaced calcar fracture can be seen on the post-operative x-ray,
119
however there was no evidence of subsidence or any need for further intervention.
120
There were nine periprosthetic fractures identified; four managed surgically and five
121
managed without surgical intervention. All were the result of a reported fall by the patient at a mean
122
time of 27 months post-surgery (range 4 days to 123 months). Five of the nine (56%) periprosthetic
123
fractures occurred within one year of the procedure. Patient and operative factors of cases that had
124
a periprosthetic fracture are shown in Table 3. Periprosthetic fractures occurred marginally more
125
commonly in females and in cases with a worse femur presentation at revision.
126
investigation of patient records showed that three of the nine cases were associated with bone 6
Further
127
quality compromise (osteopenia, ETO non-union and a cyst in the proximal femur), three had a
128
potential secondary reason for the fall (myocardial infarction, foot-drop and dislocation) and three
129
were the result of a pure mechanical fall. At the time of fracture, there was no evidence of proximal
130
stress shielding or change in the Paprosky femur classification in any cases.
131
Stem height was measurable in 218 cases (86%). In cases where measurement was not
132
possible this was due to either no immediate post-operative x-ray or no consistent landmark on the
133
series of x-rays. Eighty-nine percent of cases (195) had subsidence of less than 5mm (Figure 3).
134
There were 6 cases with subsidence of more than 10 mm. None of these six required further
135
surgical intervention. Patient and operative characteristic of cases that had a subsidence are shown
136
in Table 3. Subsidence was marginally more common in cases that were revised from a cemented
137
primary than an uncemented (12% vs. 4% respectively). Seven of the thirteen revised cases had no
138
subsidence. One case had subsidence of 5-10 mm which was revised for aseptic loosening.
139 140
Proximal Bone Remodelling:
141
Radiographs were assessed for proximal bone loading in 185 cases (73% of cohort). Cases
142
excluded were due to inadequate follow-up (32) inadequate post-operative x-ray (17), deceased
143
prior to routine review (12), infection (4), or peri-prosthetic fracture within the follow-up period (4).
144
The mean follow-up period for proximal bone loading analysis was 75 months. Ninety-six percent of
145
cases showed no proximal stress shielding (15% showing proximal bone regeneration). No stress
146
shielding was observed when an uncemented stem was used in the primary THA. Figure 4 a, b and
147
c show progressive bone remodelling in one case.
148
The femoral bone loss was re-evaluated for cases that required stem re-revision on the
149
latest pre-revision x-ray (Table 2, column 8). In ten of the thirteen re-revised cases the Paprosky
150
grading did not increase. The cases where an increase in bone loss was observed were related to
151
periprosthetic fracture, ETO non-union and aseptic loosening as a result of an insufficiency fracture
7
152
noted on immediate post-operative x-rays. Bone remodelling outcomes and demographics of cases
153
are presented in Table 4.
154
Patient Reported Outcomes:
155
Oxford Hip Scores (collected 6-18 months post-surgery) were available for 49% of the cohort
156
with a mean score of 34 (+/- 11.7 SD). Thigh pain was reported by patients in seven cases (3%). Of
157
these seven cases, only one stem showed evidence of subsidence (ultimately revised). No cases
158
had evidence of proximal stress shielding or distal hypertrophy. One case had an ETO with union
159
evident at 12 months’ post-surgery.
160
8
161
Discussion
162
This study identified a survivorship of 97.33% (CI 94-100) at six years for aseptic stem
163
loosening. Three studies have previously reported revision rates for this stem in the literature [13-
164
14, 18]. We report a stem re-revision rate of 5.12% at mean 62 months follow-up, which is
165
consistent with the two previous independent studies reporting 1.69% [14] and 7.32 % [18]. The
166
report by Makani et al [14] had a comparable mean follow-up period with our study, however the
167
minimum 10 year follow-up period in the Reikerâs et al [18] may explain the higher reported revision
168
rate. Both of these studies are limited however by small sample sizes, with between 41 and 60
169
cases in each study. We combined data from two large UK hip units in order to gain a sample five
170
times greater than the previous studies. The designer group (ARTRO) study reported no failures in
171
41 cases with a mean follow-up period of 30 months [13]. This data was subsequently re-reviewed
172
with follow-up at a mean 96 months and reported from 152 revisions there were 3 stems revised for
173
aseptic loosening [19]. The Kaplan-Meier survivorship for aseptic loosening was reported as 97.3%
174
(CI 53–100) at 17.4 years which is comparable to the findings presented in our study [19]. National
175
level data (U.K) shows that the cumulative percentage probability rate of re-revision (for any-cause)
176
at three years is 9.6% for un-cemented revision THA and 9.0% for cemented revision THA [3]. We
177
report a cumulative percentage probability re-revision rate (for any-cause) of 6.2% at three years.
178
The aseptic re-revision rate in this study is comparable to other revision stem prostheses
179
reported in the literature (Table 5). Direct comparisons between different prosthesis are inevitably
180
difficult due to variances in patient characteristics, study design and factors reported. An important
181
factor is the degree of femoral bone deficiency, as a high correlation between failure of fixation and
182
the extent of bone loss present at revision has been demonstrated in extensively porous-coated
183
femoral components20.
184
A recent review of over 2,000 cases in the Swedish Hip Arthroplasty Register (SHAR)
185
compared cemented and uncemented revision stems and reported comparable unadjusted 10-year
186
survival of 88% (CI 86–90) and 85% (95% CI 83–87) respectively [27]. It is important to note that
9
187
proximally fixed uncemented revision stems were not included in the SHAR review due to its limited
188
use in Sweden. Although comparable survival rates were reported between stems, the reasons for
189
re-revision differed, with uncemented revision stems having half the number of cases re-revised due
190
to aseptic loosening (25 vs. 52), however higher numbers of re-revision due to dislocation (34 vs
191
14). These findings were explained by a shorter follow up period for uncemented stems (mean 5 vs
192
7.5 years) and early subsidence/rotation leading to poorer biomechanics restoration in uncemented
193
stems. The re-revision rate reported for aseptic loosening and dislocation for uncemented stems in
194
the SHAR study were higher to that reported here in our study with similar follow-up, 2.9% vs 1.2%
195
and 2% vs 1.6% respectively. The most common reasons for re-revision in our cohort were
196
infection, aseptic loosening and periprosthetic fracture. The SHAR study concluded that cemented
197
revision stems are advantageous in an elderly patient (>75 years) as there was lower early re-
198
revision rates, an influence they theorized as a result of compromised bone stock. In our series we
199
did not identify an increased risk of re-revision in patients >75 years. The mean age of re-revised
200
cases was less than the cohort mean (65 vs 71 years) and less than a third of revised cases were
201
>75 years at the time of surgery. Neither did we find an increase in early failure in older patients;
202
mean time to re-revision 43 months in cases > 75 years and 46 months in cases < 75 years. Thus,
203
based on our findings, the use of monoblock, HA coated uncemented revision stem is a reliable
204
option in older patients.
205
The traditional Wagner type revision stem has well evidenced survivorship but by design
206
fails to load proximal bone due to diaphyseal fixation. The decision making in whether to use a
207
modular or non-modular (monoblock) stem has been discussed by Cross & Paprosky [28] but
208
remains a challenging issue for the operating surgeon. Modular stems are becoming increasingly
209
popular in revision arthroplasty despite the evidence of comparative outcomes when using a non-
210
modular stem in cases with simpler femoral defects [29]. Huddleston et al [24] directly compared the
211
survivorship of modular and non-modular hip revisions at 9 years and reported a superior outcome
212
with modular stems (91% vs. 86%). This study however compared the outcomes of 8 separate
213
stem designs, some only being used in a singular case.
10
214
There were twenty-one cases that required re-revision surgery in our cohort, thirteen of
215
which involved the stem. The mean time to aseptic stem re-revision was 40 months, with only two
216
cases failing in the first twelve months; both for periprosthetic fracture following a fall. There was
217
one case of stem fracture requiring re-revision, reasoned to be due to distal fixation as a result of
218
inadequate femoral preparation. The incidence of stem fractures in monoblock stems is low in
219
comparison to modular stem systems, which are reported to have a higher risk of fretting release of
220
corrosion particles and fracture at the modular junctions [31-32]. One re-revision was due to the
221
failed union of the ETO, resulting in a clinically significant leg-length discrepancy and pain. This was
222
considered to be a result of the ETO extending too far distally and encroaching upon the slots in the
223
extended distal portion of stem. There were 30 cases (11.8%) that required ETO in this series; all
224
other cases demonstrated good bone healing without issue. Therefore, we recommend that the use
225
Corail® Revision Stem is safe after ETO when there is a minimum of 4 cm of stem distally beyond
226
the cut of the ETO.
227
There were 9 periprosthetic fractures identified; 6.7% with a minimum 5 year follow up. Five
228
of these occurred within the first year following surgery. Epidemiological studies have identified a
229
significantly greater risk of post-operative periprosthetic fractures with revision hip arthroplasty in
230
comparison to primary (1-3.5% vs 4-30%) occurring at a mean 5.5 years post-surgery, with
231
uncemented stems having a 30% higher risk of periprosthetic fracture [33-35]. Specific risk factors
232
of female gender, Dorr C type bone and an ASA grade 3 or higher have been shown to be
233
associated with a 1.5 – 2.5 greater risk of periprosthertic fracture following primary arthroplasty [35].
234
In our study, analysis of periprosthetic fracture cases did not identify any clear factors that
235
predisposed patients to increased risk. Female patients and cases with higher a Paprosky femur
236
classification were slightly more prone, however the differences were marginal, and no significant
237
effect could be concluded from this small number of cases.
238
The occurrence of intraoperative fractures can alter the outcome following revision surgery,
239
especially if not managed effectively at the time. Intraoperative fractures, including canal
240
perforations, occurred in 11% of surgeries in this series; this includes fractures that occurred during 11
241
extraction of the previous prosthesis. This finding is similar to that reported following revision
242
arthroplasty with a cementless, modular stem (13%) [36]. The study also reported that the distal
243
shaping of a stem has a significant effect on the risk of causing an intraoperative fracture (splined-
244
tapered vs. straight stem) [36]. The tapered stem used in this study has distal slots in the coronal
245
and sagittal plane, which aim to minimize force transfer by preventing a rigid isthmus fit (Figure 1).
246
Makani et al reported no intraoperative fractures in 55 revisions using the Corail® Revision Stem
247
[18]. Two recent studies directly compared cementless modular and non-modular stem designs and
248
reported higher rates of intraoperative fractures in modular systems [24, 36]. They reasoned this to
249
be due to errors in surgical technique with a modular system (under-reaming or in-vivo assembly of
250
prosthesis), thus the results favoured the simplicity of a non-modular stem design.
251
Subsidence (> 5mm) was identified in 11% of cases, with six of these cases having
252
subsidence of greater than 10mm. This is comparable with the results (11.1%) reported by Palumbo
253
et al [37] with a modular, titanium, tapered femoral stem (Restoration Modular Stem, Stryker). This
254
study did however look at femur types with severe proximal bone loss (type III & IV Paprosky).
255
Restrepo et al [38] reported a subsidence rate of just 2% when using a modular uncemented stem in
256
118 cases. This cohort however was made up of a higher proportion of simpler (Type I) femur types
257
(57% vs. 27% in this study). Subsidence of greater than 5 mm is reported to indicate instability of
258
the stem, however the clinical importance of subsidence in relation to survivorship is not fully
259
understood [17]. A recent study exploring subsidence with the primary Corail© stem reported
260
subsidence of >13mm was required for a patient to be symptomatic [39]. Although six cases in this
261
series had subsidence of more than 10mm, none required any further intervention. We can
262
therefore conclude that early subsidence of this stem does not appear to be related to stem failure.
263
Analysis of subsided cases did not identify any clear factor that may predispose to subsidence with
264
this stem model. Subsidence was slightly more prevalent in males, in cases where the primary stem
265
was cemented and in Paprosky Type III or higher. As with the periprosthetic fracture case analysis,
266
differences were small and no significant causative relationship was seen.
12
267
The philosophy of the Corail® is to use the least-invasive implant that will ensure adequate
268
primary and biological fixation. The benefits of the Corail® Revision Stem are its simplicity, bone
269
regeneration and loading of proximal bone, along with the fact that it is considerate to the potential
270
that further surgery may be required [12, 19]. We were able to investigate proximal bone
271
remodelling in 185 cases with a minimum follow-up of 2 years and a mean follow-up of 6.3 years. In
272
81% of cases adequate loading was achieved to ensure no stress shielding occurred. In 15% of
273
cases, sufficient proximal bone loading was achieved to produce bone regeneration. Proximal bone
274
loss was evident in 8 (4%) cases, implying that adequate loading of the proximal bone was not
275
achieved in these cases. Previous reports into bone remodelling using the identical stem have
276
varied, with no femoral resorption or stress shielding reported by Makani et al [18] in 41 cases with 5
277
year follow up, however Reikerås & Gunderson [14] reported bone atrophy to be present in Gruen
278
zone 1, 2 & 7 in 3-14% of cases with a minimum 10 year follow-up. Our findings support the theory
279
of proximal bone loading, with a greater degree of proximal bone regeneration seen compared to
280
proximal stress shielding. Older age did not relate to cases with stress shielding, with the mean age
281
of cases that had proximal stress shielding lower than the mean age for those with no change and
282
bone hypertrophy. Proximal bone regeneration was apparent in cases with both an ETO and in
283
cases with a Type III Paprosky femur type, a positive finding supporting the use of this stem in these
284
more complex cases. It is not determinable whether this regeneration relates to structural support in
285
the diaphysis.
286
In cases that required re-revision, the Paprosky femoral classification at re-revision was
287
assessed. The mean time to re-revision was 35 months (range 5 – 96) and as changes in resorptive
288
remodelling are present within the first 6-24 months, sufficient time had elapsed for the development
289
of stress shielding to have occurred [40]. The majority of cases maintained the same Paprosky
290
classification at re-revision, with two cases demonstrating proximal bone regeneration (regression of
291
Paprosky classification). Three of the revision cases had progression of femoral deficiencies, all of
292
which failed to adequately load the proximal bone either due to failure of the HA to bind to the host
293
bone or due to proximal bone insufficiency. A distal fixation type of stem is therefore advised in
13
294
cases with more severe diaphyseal bone loss (Paprosky Type IIIb & IV) [28]. A more complex stem
295
system was required at re-revision in most cases despite no evidence of lysis or progression of the
296
Paprosky classification. This was due to the diaphyseal disruption caused by the periprosthetic/stem
297
fractures. Girdlestone procedures in this series were performed due to infection and non-
298
reconstructable acetabular bone, despite the stem appearing radiologically to have integrated well.
299
The mean OHS of 34 is comparable to outcomes reported in the literature following revision
300
arthroplasty with an uncemented revision stem [41]. Failure to complete follow-up outcome
301
measures at follow-up appointments, most notably for those performed earlier in this series, was the
302
main reason for the number without available PROMS. Pre-operative scores were not available to
303
enable calculation of the change in functional outcome achieved by the revision surgery. Other
304
studies that have looked at patient reported outcomes using the same stem design have reported
305
similar positive scores [18-19]. The lack of PROMS data for over half the cohort is disappointing;
306
however a sample size of 124 still represents the largest published data relating to PROMS for the
307
Corail Revision Stem. We identified a 3% incidence of thigh pain with no radiological evidence to
308
suggest causation from stem positioning/distal hypertrophy in all but one case; revision due to failed
309
ETO union with associated thigh pain. The prevalence of thigh pain in uncemented hip arthroplasty
310
is reported to vary between 1-14% in extensively coated uncemented primary stems [42]. No
311
significant thigh was reported in either of the previous independent studies using the same
312
monoblock, hydroxyapatite coated titanium stem [14, 18].
313
There are limitations within this study. Firstly, the overall follow-up rate of 93% demonstrates a
314
small but important drop-out rate which may have positively biased the findings. Secondly, forty-
315
eight percent of cases reported in this study had less than five year’s minimal radiological follow-up.
316
The reasons for loss to follow-up related largely to patient’s failure to attend arranged appointments.
317
This studies aims were to investigate a number of factors related to revision surgery, not solely
318
survivorship, such as intra-operative issues and radiological changes occurring within five years
319
(subsidence and proximal bone lysis). Failure following revision surgery is demonstrated to occur
320
sooner post-operatively than for primary arthroplasty, and as such we believe the inclusion of cases 14
321
with a minimum one year follow up is justified. A study of 1,100 THA revisions by Springer et al [43]
322
reported a mean time to re-revision of 3.7 years; mean follow-up in our cohort is over 5 years. In
323
order to improve the confidence of our analysis, national (NJR) records were searched relating to
324
each operating surgeon for re-revision procedures conducted. This secondary tier follow-up enables
325
greater confidence in the survivorship; mean follow-up using NJR sourced data is 105 months/8.75
326
years, with over 80% of cases having greater than 5 year follow-up. As we cannot guarantee that all
327
procedures relating to the cases in this study were accurately recorded on the NJR we have classed
328
follow-up time by radiographic evidence of survivorship.
329
In conclusion, this study describes the largest series of cases using the Corail® Revision Stem
330
and found good survivorship, low rates of complications and subsidence, good bone preservation
331
and positive patient reported outcomes. With an aging population and increasing numbers of hip
332
arthroplasties being performed it is important to continue to investigate the outcomes in revision
333
surgery. This study demonstrates that for moderate femoral deficiencies a monoblock, HA-coated
334
titanium stem can be considered a viable option for revision hip arthroplasty and in a significant
335
proportion of cases will allow proximal bone regeneration.
336
15
337
References
338
1. Kurtz S, Ong K, Lau E, Mowat F, Halpern M. Projections of primary and revision hip and
339
knee arthroplasty in the United States from 2005 to 2030. Jounral Bone & Joint Surgery
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America 2007;89(4):780-5
341 342 343 344 345
2. Patel A, Pavlou G, Mujica-Mota RE, Toms AD. The epidemiology of revision total knee and hip arthroplasty in England and Wales. Bone Joint J 2015;97-B:1076–1081 3. National Joint Registry for England, Wales, Northen Island and the Isle of Man (2017) 14th Annual Report. 4. Palmer, A.J.R., Dimbylow, D., Giritharan, S. and Deo, S., 2012, July. How accurate is
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National Joint Registry data?. In Orthopaedic Proceedings (Vol. 94, No. SUPP_XXIX, pp.
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5. Porter, M., Armstrong, R., Howard, P., Porteous, M. and Wilkinson, J.M., 2019. Orthopaedic
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6. Bozic KJ, Kurtz SM, Lau E, Ong K, Vail TP, Berry DJ. The epidemiology of revision total hip arthroplasty in the United States. J Bone Joint Surg Am 2009;91(1):128-33 7. Sadoghi P, Liebensteiner M, Agreiter M, Leithner A, Böhler N, Labek G. Revision surgery
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356 357 358 359
8. Ulrich SD, Seyler TM. "Total hip arthroplasties: What are the reasons for revision?" Int Orthop 2008;32(5):597-604 9. Moreland JR, Bernstein ML Femoral revision hip arthroplasty with uncemented, porouscoated stems. Clinical Orthopaedic Related Research 1995;319:141-150
360
10. Paprosky W, Greidanus N, Antoniou J. Minimum 10-Year-Results of Extensively Porous-
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Coated Stems in Revision Hip Arthroplasty. Clinical Orthopaedics & Related Research
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363 364 365
11. Chen JH, Liu C, You L. Boning up on Wolff's law: mechanical regulation of the cells that make and maintain bone. Journal of Biomechanics 2010;43(1):108-118 12. Engh, C.A., Bobyn, J.D. and Glassman, A.H., 1987. Porous-coated hip replacement. The
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368 16
369 370 371
13. Pinaroli A, Lavoie F, Cartillier J-C, Neyret P, Selmi TAS. Conservative Femoral Stem Revision: Avoiding Therapeutic Escalation. Journal of Arthroplasty 2009:24(3):365-373 14. Reikerås O, Gunderson RB. Excellent results with femoral revision surgery using an
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extensively hydroxyapatite-coated stem: 59 patients followed for 10-16 years. Acta
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15. Jacquot L, Bonnin MP, Machenaud A, Chouteau J, Saffarini M, Vidalain J-P. Clinical and
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16. Dawson J, Fitzpatrick R, Carr A, Murray D. Questionnaire on the perceptions of patients about total hip replacement. J Bone Joint Surg Br 1996;78(2):185-90 17. Engh CA, Massin P, Suthers KE. Roentgenographic assessment of the biologic fixation of porous surfaced femoral component. Clin Orthop 1990;257:107-128 18. Makani A, Kim TWB, Kamath AF, Garino JP, Lee G-C. Outcomes of Long Tapered
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Hydroxyapatite-Coated Stems in Revision Total Hip Arthroplasty. The Journal of Arthroplasty
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2014;29:827-830
384
19. Vidalain J-P, Ait Si Selmi T, Beverland D, Young S, T Board, Boldt J G, S A Brumby. The
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CORAIL® Hip System: A Practical Approach Based on 25 Years of Experience. Berlin:
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Springer, 2011:155-190
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20. Weeden SH, Paprosky WG. Minimal 11-year follow-up of extensively porous-coated stems
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in femoral revision total hip arthroplasty. Journal of Arthroplasty 2002;17(4:1);134–137
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21. Trikha SP, Singh, Raynham OW, Lewis JC, Mitchell PA, Edge AJ. Hydroxyapatite-ceramic-
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coated femoral stems in revision hip surgery. Journal of Bone & Joint Surgery (Br)
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2005;87(8):1055-1060
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22. Lamberton TD, Kenny PJ, Whitehouse SL, Timperley AJ, Gie GA. Femoral Impaction
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Grafting in Revision Total Hip Arthroplasty: A Follow-Up of 540 Hips. The Journal of
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Arthroplasty 2011;26 (8):1154-1160
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23. Chang JD, Kim T-Y, Rao MB, Lee S-S, Kim I-S. Revision Total Hip Arthroplasty Using a
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Tapered, Press-Fit Cementless Revision Stem in Elderly Patients. J Arthroplasty
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2011;26(7):1045–1049
398 399
24. Regis D, Sandri A, Bonetti I, Braggion M, Bartolozzi P. Femoral revision with the Wagner tapered stem: a ten- to 15-year follow-up study. Bone Joint Surg Br 2011;93(10):1320-1326 17
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25. Pelt CE, Madsen W, Erickson JA, Gililland JM, Anderson MB, Peters CL. Revision total hip
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arthroplasty with a modular cementless femoral stem. J Arthroplasty 2014;29(9):1803-1807
402
26. Riesgo AM, Hochfelder JP, Adler EM, Slover JD, Specht LM, Iorio R. Survivorship and
403
Complications of Revision Total Hip Arthroplasty with a Mid-Modular Femoral Stem. J
404
Arthroplasty 2015;30(12):2260-2263
405
27. Tyson, Y., Rolfson, O., Kärrholm, J., Hailer, N.P. and Mohaddes, M., 2019. Uncemented or
406
cemented revision stems? Analysis of 2,296 first-time hip revision arthroplasties performed
407
due to aseptic loosening, reported to the Swedish Hip Arthroplasty Register. Acta
408
orthopaedica, pp.1-10.
409 410 411 412 413
28. Cross MB, Paprosky WG. Managing femoral bone loss in revision total hip replacement: fluted tapered modular stems. Bone Joint J 2013;95-B(11A): 95-97 29. Konan S, Garbuz DS, Masri BA, Duncan CP. Non-modular tapered fluted titanium stems in hip revision surgery: gaining attention. Bone Joint J 2014;96-B(11A):56-59 30. Huddleston JI, Tetreault MW, Yu M, Bedair H, Hansen VJ, Choi HR, Goodman SB, Sporer
414
SM, Della Valle CJ. Is There a Benefit to Modularity in 'Simpler' Femoral Revisions? Clin
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Orthop Relat Res 2016;474(2):415-420
416
31. Cook, S.D., Barrack, R.L. and Clemow, A.J., 1994. Corrosion and wear at the modular
417
interface of uncemented femoral stems. The Journal of bone and joint surgery. British
418
volume, 76(1), pp.68-72.
419
32. Lakstein, D., Eliaz, N., Levi, O., Backstein, D., Kosashvili, Y., Safir, O. and Gross, A.E.,
420
2011. Fracture of cementless femoral stems at the mid-stem junction in modular revision hip
421
arthroplasty systems. JBJS, 93(1), pp.57-65.
422
33. Gromov, K., Bersang, A., Nielsen, C.S., Kallemose, T., Husted, H. and Troelsen, A., 2017.
423
Risk factors for post-operative periprosthetic fractures following primary total hip arthroplasty
424
with a proximally coated double-tapered cementless femoral component. The bone & joint
425
journal, 99(4), pp.451-457.
426
34. Frenzel, S., Vécsei, V. and Negrin, L., 2015. Periprosthetic femoral fractures—incidence,
427
classification problems and the proposal of a modified classification scheme. International
428
orthopaedics, 39(10), pp.1909-1920.
429
35. Singh, J.A., Jensen, M.R., Harmsen, S.W. and Lewallen, D.G., 2013. Are gender,
430
comorbidity, and obesity risk factors for postoperative periprosthetic fractures after primary
431
total hip arthroplasty?. The Journal of arthroplasty, 28(1), pp.126-131.
18
432
36. Huang Y, Zhou Y, Shao H, Gu J, Tang H, Tang Q. What Is the Difference Between Modular
433
and Nonmodular Tapered Fluted Titanium Stems in Revision Total Hip Arthroplasty. J
434
Arthroplasty 2017;32(10):3108-3113
435
37. Palumbo BT, Morrison KL, Baumgarten AS, Stein MI, Haidukewych GJ, Bernasek TL
436
Results of revision total hip arthroplasty with modular, titanium-tapered femoral stems in
437
severe proximal metaphyseal and diaphyseal bone loss. J Arthroplasty 2013;28(4):690-4
438 439 440 441 442 443 444
38. Restrepo C, Mashadi M, Parvizi J, Austin MS, Hozack WJ. Modular femoral stems for revision total hip arthroplasty. Clin Orthop Relat Res. 2011;469(2):476-82 39. Selvaratnam V, Shetty V, Sahni V. Subsidence in Collarless Corail Hip Replacement. Open Orthop J 2015;29(9):194-197 40. Engh CA, Bobyn JD, Glassman AH. Porous coated hip replacement: the factors governing bone ingrowth, stress shielding, and clinical results. J Bone Joint Surg Br 1987;69:45-55. 41. Richards CJ, Duncan CP, Masri BA, Garbuz DS. Femoral revision hip arthroplasty: A
445
comparison of two stem designs. Clinical Orthopaedics and Related Research
446
2010;468(2):491-496
447
42. Brown, T.E., Larson, B., Shen, F. and Moskal, J.T., 2002. Thigh pain after cementless total
448
hip arthroplasty: evaluation and management. JAAOS-Journal of the American Academy of
449
Orthopaedic Surgeons, 10(6), pp.385-392.
450 451
43. Springer BD, Fehring TK, Griffin WL. Why Revision Total Hip Arthroplasty Fails. Clin Orthop Relat Res 2009;467(1):166–173
452
19
453
Figure Legend:
454
Figure 1. The Corail® Revision Stem with close-up of slots in the distal stem
455
Figure 2 a. Kaplan-Meier survivorship (Revision for any cause): 93.97% at 6 years (CI 90 –
456
98) b.Kaplan-Meier survivorship (aseptic stem revision): 97.33% at 6 years (CI 94 - 100)
457
Figure 3. Bar chart of radiological subsidence
458
Figure 4. Images of the Corail Revision Stem with proximal bone remodelling; (a) pre-operative, (b)
459
post-operative and (c) 10 year follow-up x-rays of a single cases
460 461
Table 1. Primary revision details & stem sizes used at revision
462
Table 2. Details of stem re-revision cases
463
Table 3. Details of cases with post-operative complications
464
Table 4. Bone remodelling outcomes
465
Table 5. Literature review of aspetic stem survivorship in revision arthroplasty
466 467 468
20
Title: Survivorship and radiological analysis of a monoblock, hydroxyapatite coated titanium stem in revision hip arthroplasty Acknowledgements: The lead author’s research assistant role was financially supported by DePuy Synthes.
Table 1. Primary revision details & stem sizes used at revision
Indication for Revision
Cases
Primary Procedure
Cases
Paprosky Classification
Cases
Stem Size Used in Revision
Cases
Aseptic stem loosening
125
Cemented THA
179
Type I
62
10
5
Aseptic cup loosening
61
Un-cemented THA
46
Type II
150
11
11
Infection
18
Cemented hemi-arthroplasty
3
Type III a
39
12
47
Periprosthetic fracture
18
Un-cemented hemi-arthroplasty
6
Type III b
3
13
10
Metal disease
15
Unknown
20
Type IV
0
14
58
Dislocation
9
15
15
Pain
4
16
64
Implant fracture
3
18
26
Pelvic lysis
1
20
11
Unknown
7
Table 2. Details of stem re-revision cases Case Gender
Age (years)
Indication for 1st Revision
Primary THA
Stem Size
Subsidence
Indication for Re-revision
Months to Paprosky Reat 1st / 2nd revision Revision
Stem used in Re-revision
1
Female
59
Infection
Uncemented
15
No measure
Infection
29
1/1
Girdlestone Procedure
2
Female
38
Infection
Cemented
12
< 5mm
Infection
40
2/2
Girdlestone Procedure
3
Male
81
AL
Cemented
14
< 5mm
Infection
43
3A / 3A
C-Stem®AMT
4
Male
61
AL
Cemented
16
< 5mm
Infection
18
3A / 2
Cemented Primary Stem
5
Female
57
AL
Cemented
10
No measure
PF
13
2/2
Reef™ Stem
6
Male
70
AL
Cemented
12
< 5mm
PF
5
2/2
Reef™ Stem
7
Male
85
AL
Cemented
16
< 5mm
PF
10
2/2
Reef™ Stem
8
Male
61
Infection
Cemented
14
< 5mm
PF
29
2/2
Proximal femoral replacement
9
Female
64
AL
Cemented
14
< 5mm
AL
34
2/4
Proximal femoral replacement
10
Male
71
AL
Uncemented
14
< 5mm
AL
96
2 / 3A
C-Stem®AMT
11
Male
61
AL
Cemented
16
5 – 10mm
AL
90
2/1
Unknown*
12
Female
51
Implant Fracture
Uncemented
16
< 5mm
ETO non-union
19
1 / 3B
Reclaim® Modular Revision Stem
13
Male
76
AL
Cemented
18
No measure
Stem fracture
28
3B / 3B
Reef™ Stem
Key: AL = Aseptic loosening, IF = Implant fracture, PF = Periprosthetic fracture. Arrow direction indicates change in Paprosky femoral classification from 1st revision to re-revision; ↔ no change, ↑ increase in Paprosky Classification (worsened), ↓decrease in Paprosky Classification (improved) * Unknown prosthesis used in revision as case referred to another hospital
Table 3. Details of cases with post-operative complications
Periprosthetic Fracture Cases
Subsided Cases
Incidence
9
23
Mean Age
72
70
Female
5 (56%)
8 (35%)
Primary Cemented Cases
8 (4%)
21 (12%)
Primary Uncemented Cases
1 (2%)
2 (4%)
Paprosky Type I
1 (2%)
6 (10%)
Paprosky Type II
6 (4%)
12 (8%)
Paprosky Type III or Higher
2 (5%)
5 (12%)
Table 4. Bone remodelling outcomes
Proximal Stress Shielding
No Change
Proximal Bone Regeneration
8 (4%)
150 (81%)
27 (15%)
71
74
83
Male (104)
66 6 (7%) 2 (2%)
71 62 (77%) 88 (85%)
68 13 (16%) 14 (13%)
Primary Cemented THA (132)
8 (6%)
102 (77%)
22 (17%)
Primary Uncemented THA (38)
0 (0%)
34 (89%
4 (11%)
Wiring In Situ (75)
4 (5%)
58 (77%)
13 (17%)
ETO (24)
1 (4%)
16 (67%)
7 (29%)
Subsidence (17)
1 (6%)
10 (59%)
6 (35%)
Paprosky Type I (40)
1 (2%)
32 (80%)
7 (18%)
Paprosky Type II (113)
5 (6%)
99 (88%)
9 (8%)
Paprosky Type III< (32)
2 (6%)
19 (59%)
11 (34%)
(Total) Cases (185) Mean Follow Up (months) Mean Age (years) Female (81)
Table 5. Literature review of aspetic stem survivorship in revision arthroplasty Author Weeden & Paprosky20 (2002) Trikha et al.21 (2005)
Cases
Stem Type
Femoral Paprosky Classification of Sample
Survivors hip (aseptic)
Follow-Up (years)
170
Extensively porous-coated nonmodular
Type I-IIIC femoral defects
96.5%
14.2
Non-modular HA- coated ceramic
Type I-IIIC femoral defects
100%
10
120
Lamberton et al.22 (2011)
540
Cemented with impaction bone grafting
Not reported
98%
10
Chang et al.23 (2011)
48
Press-fit un-cemented
Type I-IIIA
98%
5.6
Wagner SL
High percentage of Type IIIA< femoral defects
96.6%
13.9
Modular un-cemented
Type I-IIIC femoral defects
97%
7
Regis et al.24 (2011)
41
Pelt et al.25 (2014)
76
Riesgo et al.26 (2015)
161
Modular un-cemented
Type I-IV femoral defects
97.5 %
6.1
Saunders et al.
254
Non-modular HA coated
Type I-IIIB femoral defects
97.3%
6
Figure 1
Survivorship (%)
Figure 2a 100 90 80 70 60 50 40 30 20 10 0 0
Follow-up (years) Number at risk Cumulative success rate Confidence limit (higher) Confidence limit (lower) Standard error
1
2
3
4
5 6 (Years) 7 Follow_up
8
9
10
11
12
0 1 2 3 4 5 6 7 8 9 10 11 12 253.5 237.5 210.5 180 147.5 124 104.5 87 65.5 42.5 23.5 10.5 4 99.61 98.34 96.44 94.78 94.78 93.97 93.97 92.82 88.24 83.53 70.77 70.77 70.77 100 100 99 98 98 98 98 98 96 94 86 94 108 99 97 94 92 91 90 90 88 81 73 55 48 33 0.004 0.008 0.013 0.016 0.018 0.021 0.023 0.027 0.037 0.052 0.079 0.118 0.191
Survivorship (%)
Figure 2b
100 90 80 70 60 50 40 30 20 10 0 0
Follow-up Number at risk Cumulative success rate Confidence limit (higher) Confidence limit (lower) Standard error
0 254 99.61 100 99 0.004
1
2
1 237 98.76 100 97 0.007
3
2 210 97.33 99 95 0.011
4
5 6 7 Follow-Up (Years)
8
9
10
3 4 5 6 7 8 178.5 147.5 123.5 104.5 87.5 64 97.33 97.33 97.33 97.33 95.05 95.05 100 100 100 100 99 100 95 95 95 94 91 90 0.012 0.013 0.014 0.016 0.023 0.026
11
12
9 41.5 95.05 101 89 0.033
10 11 12 22.5 10.5 4 90.60 90.60 90.60 102 107 118 79 74 63 0.059 0.086 0.139
Figure 3
Subsidence 250
Cases
200
195
150 100 50
17
6
0 < 5 mm
5 - 10 mm Degree of Subsidence
> 10 mm
Figure 4 a / b / c
a.
b.
c.
Figure Legend: Figure 1. The Corail® Revision Stem with close-up of slots in the distal stem Figure 2 a. Kaplan-Meier survivorship (Revision for any cause): 93.97% at 6 years (CI 90 – 98) b.Kaplan-Meier survivorship (aseptic stem revision): 97.33% at 6 years (CI 94 - 100) Figure 3. Bar chart of radiological subsidence Figure 4. Images of the Corail Revision Stem with proximal bone remodelling; (a) preoperative, (b) post-operative and (c) 10 year follow-up x-rays of a single cases Table Legend: Table 1. Primary revision details & stem sizes used at revision Table 2. Details of stem re-revision cases Table 3. Details of cases with post-operative complications Table 4. Bone remodelling outcomes Table 5. Literature review of aspetic stem survivorship in revision arthroplasty
S0883-5403(20)30118-2
DOI:
https://doi.org/10.1016/j.arth.2020.01.081
Reference:
YARTH 57789
To appear in:
The Journal of Arthroplasty
Received Date: 22 November 2019 Revised Date:
17 January 2020
Accepted Date: 30 January 2020
Please cite this article as: Saunders P, Shaw D, Sidharthan S, Siney P, Young SK, Board T, Survivorship and Radiological Analysis of a Monoblock, Hydroxyapatite Coated Titanium Stem in Revision Hip Arthroplasty, The Journal of Arthroplasty (2020), doi: https://doi.org/10.1016/ j.arth.2020.01.081. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2020 Elsevier Inc. All rights reserved.
Title: Survivorship and Radiological Analysis of a Monoblock, Hydroxyapatite Coated Titanium Stem in Revision Hip Arthroplasty Paul Saunders1, Debbie Shaw2, Sijin Sidharthan2, P Siney2, Stephen K Young1, Tim Board2 1. Department of Orthopaedics, Warwick Hospital, South Warwickshire NHS foundation Trust, Warwick, CV34 5BW, United Kingdom 2. Wrightington Centre for Hip Surgery, Wrightington Hospital, Hall Lane, Appley Bridge, Wigan, WN6 9EP, United Kingdom
Please address all correspondence to: Paul Saunders Department of Orthopaedics Warwick Hospital South Warwickshire NHS foundation Trust Warwick CV34 5BW United Kingdom [email protected]
1
Title: Survivorship and Radiological Analysis of a Monoblock, Hydroxyapatite Coated
2
Titanium Stem in Revision Hip Arthroplasty
3
Abstract
4
Aims: We evaluated the survivorship, incidence of complications, radiological subsidence, proximal
5
stress-shielding and patient reported outcomes of a conservative, monoblock, HA coated femoral
6
stem.
7
Methods: This retrospective cohort study reports on 254 revision hip arthroplasties between
8
January 2006 and June 2016. The mean age of patients was 71 years. The mean length of follow-
9
up was 62 months (range 12-152 months).
10
Results: There were 13 stem re-revisions; infection (4), periprosthetic fracture (4), aseptic stem
11
loosening (3), stem fracture (1), and ETO non-union (1). Kaplan-Meier aseptic stem survivorship
12
was 97.33% (CI 94-100) at 6 years. There were 29 intraoperative fractures. There were 6 cases of
13
subsidence greater than 10mm however none required revision. Ninety-six percent of cases
14
showed no proximal stress shielding. Thigh pain was reported in 3% of cases.
15
Conclusion: This study confirms that this stem provides good survivorship at 6 years, acceptable
16
complication rates, excellent proximal bone loading, low incidences of thigh pain and reliable clinical
17
performance in revision hip arthroplasty.
18
Word count: 161
19
Key message:
20
A monoblock, fully hydroxyapatite coated titanium stem is reliable in revision arthroplasty with mild-
21
moderate femur deficiencies.
1
22
Introduction
23
Since the start of the 21st century there has been a steady increase in the number of total hip
24
arthroplasties performed globally [1 ,2]. This demand is projected to continue to increase by 134%
25
for primary and 31% for revision hip surgery in the UK over the next two decades [2]. National (UK)
26
database reported hip re-revision rates are 9.09% at 5 years and 14.40% at 10 years [3]. National
27
databases provide case numbers for large scale survivorship analysis. Their reliability at a unit level
28
however has been questioned with a recent review published in 2019 stating that 10% of revision
29
cases performed in the UK were not captured; this equates to 800 revision cases per year not
30
considered in survivorship statistics [4, 5].
31
Data from worldwide arthroplasty registers indicate that the most common indications for hip
32
revision are aseptic loosening, dislocation, pain, septic loosening and periprosthetic fracture; the
33
ranking of indications varies by country [3, 6-7]. Aseptic loosening is associated with bone loss at
34
the metaphysis and diaphysis [8]. This loss of proximal structural support makes revision
35
arthroplasty a complex challenge. The traditional approach is to by-pass the depleted proximal bone
36
stock and achieve distal fixation using an appropriately designed stem. Distal loading of bone
37
however has been shown to result in proximal bone stress shielding (based on Wolff’s law of
38
remodelling) and higher incidences of mid-thigh pain [9-11]. Loss of proximal bone is evident from
39
two years post-surgery and ultimately makes subsequent attempts at revision surgery more
40
technically challenging with a greater risk of complications [12]. An alternative philosophy to distal
41
fixation is referred to as ‘conservative revision’. It uses a ‘top-down’ approach, aiming to achieve
42
fixation “as proximal as possible and as distal as necessary” [13]. This approach relies on a stem
43
design that maximally loads the remaining proximal bone [13-14].
44
The primary aim of this study was to determine the survivorship and incidence of intra- and post-
45
operative complications with a monoblock, fully hydroxyapatite (HA) coated femoral stem in revision
46
hip arthroplasty (single stem design). The secondary aim was to evaluate the conservative
2
47
approach rationale of proximal bone loading, reduced thigh pain and provision of bone stock in
48
cases of re-revision.
49
3
50
Method
51
A retrospective cohort study was conducted utilizing data from two high volume hip units in
52
the United Kingdom. Between January 2006 and June 2016, 272 femoral stem revisions (262
53
patients) were performed using a long, tapered, monoblock, HA coated, titanium stem (Corail®
54
Revision Stem, DePuy, Leeds, UK; previously named the KAR™). The revision stem is based on
55
the principles of the established primary stem (CORAIL®, DePuy, Leeds, UK), which has a
56
survivorship for stem revision of 93.6% at 30 years [15]. The revision stem has the same proximal
57
shape as the primary stem however it is 40 mm longer and has coronal and sagittal slots in the
58
extended distal portion to give the stem the flexibility to accommodate to the shape of femur and
59
avoid distal load transfer (Figure 1). It is indicated in revision hip arthroplasty with Paprosky types I,
60
II and IIIa femoral bone deficiencies, which make up approximately 89% of femur presentations in
61
revision arthroplasty [10].
62
There were 254 (93%) cases in 244 patients with a minimum one-year follow-up. There were
63
134 male and 110 female patients with a mean age at surgery of 71 years (range 46 – 96 years).
64
The mean length of radiological follow-up was 62 months (range 12-152). Thirty-seven percent of
65
cohort was over 75 years at the time of surgery. Sixty-seven (26%) patients died during the follow-
66
up period at a mean of 69 months post-surgery (range 16 – 133). At 5 years 134 cases had
67
radiological follow-up (52% of original cohort).
68
Indications for revision, type of primary procedure, classifications of femoral bone loss
69
(graded on the pre-operative x-ray; Paprosky Classification) [10] and the number of stem sizes used
70
at revision are presented in Table 1. In 2012, additional sized stems (sizes 11, 13 and 15) and a
71
high off-set version (7mm of lateralization) were introduced to expand the available range. Twelve
72
(5%) of the stems used were the high off-set version.
73
Surgeries were performed by the senior authors at each unit (SKY & TB) in 55% of cases,
74
with the remaining performed by 8 consultant surgeons across the two units. Posterior and lateral
75
surgical approaches were used and post-operatively patients were either permitted full or partial
76
weight-bearing for up to six weeks; dependent on specific surgeon/patient factors. Follow-up
77
evaluation of each patient was routinely scheduled at 6 weeks, 1, 5 and 10 years post-operatively. 4
78
The protocol for the study was approved by the local Trusts Research and Development
79
departments.
80
Data Extraction & Analysis
81
Local clinical records, radiographs, NHS Spine and unit level National Joint Registry (NJR)
82
data were analysed. Intraoperative complications were identified via radiographs and operation
83
notes. The occurrence of thigh pain was determined from follow-up clinic letters. Kaplan-Meier
84
survival data were used to construct the survival probabilities of implants, with 95% confidence
85
interval (CI). Patients’ functional outcomes were assessed using the Oxford Hip Score recorded at
86
6-18 months post-surgery [16].
87
Radiographic analysis was completed using the PACS system (Insight PACS, Insignia
88
Medical Systems, U.K) by two lead investigators (PS & DS). Radiographs were standardized for
89
magnification by using the calibration ball or, if not available, by measuring the known diameter of
90
the prosthetic head. Subsidence was calculated as the difference in stem height between the
91
immediate post-operative and one-year radiograph; using the method described by Engh & Masin
92
[17]. This method measures the change in vertical distance from the superior tip of the greater
93
trochanter to the shoulder of the prosthesis. The distance measured was grouped accordingly; ≤ 5
94
mm, 5–10 mm or > 10 mm. Greater than 5 mm was considered to indicate stem subsidence. The
95
Kappa coefficient for subsidence grouping was calculated as 1.0 for inter- and intra-rater reliability;
96
indicating a high level of agreement. Assessment of bone remodelling was conducted from the most
97
recent available x-ray; a minimum follow-up period of 2 years was required for cases included in this
98
analysis. Proximal bone remodelling was recorded as proximal stress shielding, no change or
99
proximal bone regeneration.
100
5
101
Results
102
Survivorship:
103
Of the 254 procedures with adequate follow up, 21 required re-revision. Eight cases did not
104
involve revision of the stem; five involving revision of the acetabular component only (four for
105
aseptic loosening and one due to recurrent dislocations) and 3 with insertion of a constrained liner
106
only due to dislocation. There were thirteen re-revisions involving removal of the femoral stem;
107
details of patient demographics, prosthesis and re-revision procedure are shown in Table 2. The
108
Kaplan-Meier survivorship with the end point as any revision was 93.97% (CI 90-98) at six years
109
(Figure 2a). Survivorship with the end point as aseptic stem revision was 97.33% (CI 94-100) at 6
110
years (Figure 2b).
111
Complications:
112
Thirty-one surgeries involved an extended trochanteric osteotomy (ETO), with one
113
case resulting in failed union and the development of complications leading to revision. In addition
114
to the four revised dislocated cases there were six dislocations in individual patients managed with
115
manipulation under anaesthetic. Dislocations occurred at a mean 33 months post-surgery with five
116
(50%) occurring within the first year. There were 29 (11%) intraoperative fractures managed with
117
cerclage wiring in all but one case. None of these fractures resulted in further complications. In the
118
case without wiring a non-displaced calcar fracture can be seen on the post-operative x-ray,
119
however there was no evidence of subsidence or any need for further intervention.
120
There were nine periprosthetic fractures identified; four managed surgically and five
121
managed without surgical intervention. All were the result of a reported fall by the patient at a mean
122
time of 27 months post-surgery (range 4 days to 123 months). Five of the nine (56%) periprosthetic
123
fractures occurred within one year of the procedure. Patient and operative factors of cases that had
124
a periprosthetic fracture are shown in Table 3. Periprosthetic fractures occurred marginally more
125
commonly in females and in cases with a worse femur presentation at revision.
126
investigation of patient records showed that three of the nine cases were associated with bone 6
Further
127
quality compromise (osteopenia, ETO non-union and a cyst in the proximal femur), three had a
128
potential secondary reason for the fall (myocardial infarction, foot-drop and dislocation) and three
129
were the result of a pure mechanical fall. At the time of fracture, there was no evidence of proximal
130
stress shielding or change in the Paprosky femur classification in any cases.
131
Stem height was measurable in 218 cases (86%). In cases where measurement was not
132
possible this was due to either no immediate post-operative x-ray or no consistent landmark on the
133
series of x-rays. Eighty-nine percent of cases (195) had subsidence of less than 5mm (Figure 3).
134
There were 6 cases with subsidence of more than 10 mm. None of these six required further
135
surgical intervention. Patient and operative characteristic of cases that had a subsidence are shown
136
in Table 3. Subsidence was marginally more common in cases that were revised from a cemented
137
primary than an uncemented (12% vs. 4% respectively). Seven of the thirteen revised cases had no
138
subsidence. One case had subsidence of 5-10 mm which was revised for aseptic loosening.
139 140
Proximal Bone Remodelling:
141
Radiographs were assessed for proximal bone loading in 185 cases (73% of cohort). Cases
142
excluded were due to inadequate follow-up (32) inadequate post-operative x-ray (17), deceased
143
prior to routine review (12), infection (4), or peri-prosthetic fracture within the follow-up period (4).
144
The mean follow-up period for proximal bone loading analysis was 75 months. Ninety-six percent of
145
cases showed no proximal stress shielding (15% showing proximal bone regeneration). No stress
146
shielding was observed when an uncemented stem was used in the primary THA. Figure 4 a, b and
147
c show progressive bone remodelling in one case.
148
The femoral bone loss was re-evaluated for cases that required stem re-revision on the
149
latest pre-revision x-ray (Table 2, column 8). In ten of the thirteen re-revised cases the Paprosky
150
grading did not increase. The cases where an increase in bone loss was observed were related to
151
periprosthetic fracture, ETO non-union and aseptic loosening as a result of an insufficiency fracture
7
152
noted on immediate post-operative x-rays. Bone remodelling outcomes and demographics of cases
153
are presented in Table 4.
154
Patient Reported Outcomes:
155
Oxford Hip Scores (collected 6-18 months post-surgery) were available for 49% of the cohort
156
with a mean score of 34 (+/- 11.7 SD). Thigh pain was reported by patients in seven cases (3%). Of
157
these seven cases, only one stem showed evidence of subsidence (ultimately revised). No cases
158
had evidence of proximal stress shielding or distal hypertrophy. One case had an ETO with union
159
evident at 12 months’ post-surgery.
160
8
161
Discussion
162
This study identified a survivorship of 97.33% (CI 94-100) at six years for aseptic stem
163
loosening. Three studies have previously reported revision rates for this stem in the literature [13-
164
14, 18]. We report a stem re-revision rate of 5.12% at mean 62 months follow-up, which is
165
consistent with the two previous independent studies reporting 1.69% [14] and 7.32 % [18]. The
166
report by Makani et al [14] had a comparable mean follow-up period with our study, however the
167
minimum 10 year follow-up period in the Reikerâs et al [18] may explain the higher reported revision
168
rate. Both of these studies are limited however by small sample sizes, with between 41 and 60
169
cases in each study. We combined data from two large UK hip units in order to gain a sample five
170
times greater than the previous studies. The designer group (ARTRO) study reported no failures in
171
41 cases with a mean follow-up period of 30 months [13]. This data was subsequently re-reviewed
172
with follow-up at a mean 96 months and reported from 152 revisions there were 3 stems revised for
173
aseptic loosening [19]. The Kaplan-Meier survivorship for aseptic loosening was reported as 97.3%
174
(CI 53–100) at 17.4 years which is comparable to the findings presented in our study [19]. National
175
level data (U.K) shows that the cumulative percentage probability rate of re-revision (for any-cause)
176
at three years is 9.6% for un-cemented revision THA and 9.0% for cemented revision THA [3]. We
177
report a cumulative percentage probability re-revision rate (for any-cause) of 6.2% at three years.
178
The aseptic re-revision rate in this study is comparable to other revision stem prostheses
179
reported in the literature (Table 5). Direct comparisons between different prosthesis are inevitably
180
difficult due to variances in patient characteristics, study design and factors reported. An important
181
factor is the degree of femoral bone deficiency, as a high correlation between failure of fixation and
182
the extent of bone loss present at revision has been demonstrated in extensively porous-coated
183
femoral components20.
184
A recent review of over 2,000 cases in the Swedish Hip Arthroplasty Register (SHAR)
185
compared cemented and uncemented revision stems and reported comparable unadjusted 10-year
186
survival of 88% (CI 86–90) and 85% (95% CI 83–87) respectively [27]. It is important to note that
9
187
proximally fixed uncemented revision stems were not included in the SHAR review due to its limited
188
use in Sweden. Although comparable survival rates were reported between stems, the reasons for
189
re-revision differed, with uncemented revision stems having half the number of cases re-revised due
190
to aseptic loosening (25 vs. 52), however higher numbers of re-revision due to dislocation (34 vs
191
14). These findings were explained by a shorter follow up period for uncemented stems (mean 5 vs
192
7.5 years) and early subsidence/rotation leading to poorer biomechanics restoration in uncemented
193
stems. The re-revision rate reported for aseptic loosening and dislocation for uncemented stems in
194
the SHAR study were higher to that reported here in our study with similar follow-up, 2.9% vs 1.2%
195
and 2% vs 1.6% respectively. The most common reasons for re-revision in our cohort were
196
infection, aseptic loosening and periprosthetic fracture. The SHAR study concluded that cemented
197
revision stems are advantageous in an elderly patient (>75 years) as there was lower early re-
198
revision rates, an influence they theorized as a result of compromised bone stock. In our series we
199
did not identify an increased risk of re-revision in patients >75 years. The mean age of re-revised
200
cases was less than the cohort mean (65 vs 71 years) and less than a third of revised cases were
201
>75 years at the time of surgery. Neither did we find an increase in early failure in older patients;
202
mean time to re-revision 43 months in cases > 75 years and 46 months in cases < 75 years. Thus,
203
based on our findings, the use of monoblock, HA coated uncemented revision stem is a reliable
204
option in older patients.
205
The traditional Wagner type revision stem has well evidenced survivorship but by design
206
fails to load proximal bone due to diaphyseal fixation. The decision making in whether to use a
207
modular or non-modular (monoblock) stem has been discussed by Cross & Paprosky [28] but
208
remains a challenging issue for the operating surgeon. Modular stems are becoming increasingly
209
popular in revision arthroplasty despite the evidence of comparative outcomes when using a non-
210
modular stem in cases with simpler femoral defects [29]. Huddleston et al [24] directly compared the
211
survivorship of modular and non-modular hip revisions at 9 years and reported a superior outcome
212
with modular stems (91% vs. 86%). This study however compared the outcomes of 8 separate
213
stem designs, some only being used in a singular case.
10
214
There were twenty-one cases that required re-revision surgery in our cohort, thirteen of
215
which involved the stem. The mean time to aseptic stem re-revision was 40 months, with only two
216
cases failing in the first twelve months; both for periprosthetic fracture following a fall. There was
217
one case of stem fracture requiring re-revision, reasoned to be due to distal fixation as a result of
218
inadequate femoral preparation. The incidence of stem fractures in monoblock stems is low in
219
comparison to modular stem systems, which are reported to have a higher risk of fretting release of
220
corrosion particles and fracture at the modular junctions [31-32]. One re-revision was due to the
221
failed union of the ETO, resulting in a clinically significant leg-length discrepancy and pain. This was
222
considered to be a result of the ETO extending too far distally and encroaching upon the slots in the
223
extended distal portion of stem. There were 30 cases (11.8%) that required ETO in this series; all
224
other cases demonstrated good bone healing without issue. Therefore, we recommend that the use
225
Corail® Revision Stem is safe after ETO when there is a minimum of 4 cm of stem distally beyond
226
the cut of the ETO.
227
There were 9 periprosthetic fractures identified; 6.7% with a minimum 5 year follow up. Five
228
of these occurred within the first year following surgery. Epidemiological studies have identified a
229
significantly greater risk of post-operative periprosthetic fractures with revision hip arthroplasty in
230
comparison to primary (1-3.5% vs 4-30%) occurring at a mean 5.5 years post-surgery, with
231
uncemented stems having a 30% higher risk of periprosthetic fracture [33-35]. Specific risk factors
232
of female gender, Dorr C type bone and an ASA grade 3 or higher have been shown to be
233
associated with a 1.5 – 2.5 greater risk of periprosthertic fracture following primary arthroplasty [35].
234
In our study, analysis of periprosthetic fracture cases did not identify any clear factors that
235
predisposed patients to increased risk. Female patients and cases with higher a Paprosky femur
236
classification were slightly more prone, however the differences were marginal, and no significant
237
effect could be concluded from this small number of cases.
238
The occurrence of intraoperative fractures can alter the outcome following revision surgery,
239
especially if not managed effectively at the time. Intraoperative fractures, including canal
240
perforations, occurred in 11% of surgeries in this series; this includes fractures that occurred during 11
241
extraction of the previous prosthesis. This finding is similar to that reported following revision
242
arthroplasty with a cementless, modular stem (13%) [36]. The study also reported that the distal
243
shaping of a stem has a significant effect on the risk of causing an intraoperative fracture (splined-
244
tapered vs. straight stem) [36]. The tapered stem used in this study has distal slots in the coronal
245
and sagittal plane, which aim to minimize force transfer by preventing a rigid isthmus fit (Figure 1).
246
Makani et al reported no intraoperative fractures in 55 revisions using the Corail® Revision Stem
247
[18]. Two recent studies directly compared cementless modular and non-modular stem designs and
248
reported higher rates of intraoperative fractures in modular systems [24, 36]. They reasoned this to
249
be due to errors in surgical technique with a modular system (under-reaming or in-vivo assembly of
250
prosthesis), thus the results favoured the simplicity of a non-modular stem design.
251
Subsidence (> 5mm) was identified in 11% of cases, with six of these cases having
252
subsidence of greater than 10mm. This is comparable with the results (11.1%) reported by Palumbo
253
et al [37] with a modular, titanium, tapered femoral stem (Restoration Modular Stem, Stryker). This
254
study did however look at femur types with severe proximal bone loss (type III & IV Paprosky).
255
Restrepo et al [38] reported a subsidence rate of just 2% when using a modular uncemented stem in
256
118 cases. This cohort however was made up of a higher proportion of simpler (Type I) femur types
257
(57% vs. 27% in this study). Subsidence of greater than 5 mm is reported to indicate instability of
258
the stem, however the clinical importance of subsidence in relation to survivorship is not fully
259
understood [17]. A recent study exploring subsidence with the primary Corail© stem reported
260
subsidence of >13mm was required for a patient to be symptomatic [39]. Although six cases in this
261
series had subsidence of more than 10mm, none required any further intervention. We can
262
therefore conclude that early subsidence of this stem does not appear to be related to stem failure.
263
Analysis of subsided cases did not identify any clear factor that may predispose to subsidence with
264
this stem model. Subsidence was slightly more prevalent in males, in cases where the primary stem
265
was cemented and in Paprosky Type III or higher. As with the periprosthetic fracture case analysis,
266
differences were small and no significant causative relationship was seen.
12
267
The philosophy of the Corail® is to use the least-invasive implant that will ensure adequate
268
primary and biological fixation. The benefits of the Corail® Revision Stem are its simplicity, bone
269
regeneration and loading of proximal bone, along with the fact that it is considerate to the potential
270
that further surgery may be required [12, 19]. We were able to investigate proximal bone
271
remodelling in 185 cases with a minimum follow-up of 2 years and a mean follow-up of 6.3 years. In
272
81% of cases adequate loading was achieved to ensure no stress shielding occurred. In 15% of
273
cases, sufficient proximal bone loading was achieved to produce bone regeneration. Proximal bone
274
loss was evident in 8 (4%) cases, implying that adequate loading of the proximal bone was not
275
achieved in these cases. Previous reports into bone remodelling using the identical stem have
276
varied, with no femoral resorption or stress shielding reported by Makani et al [18] in 41 cases with 5
277
year follow up, however Reikerås & Gunderson [14] reported bone atrophy to be present in Gruen
278
zone 1, 2 & 7 in 3-14% of cases with a minimum 10 year follow-up. Our findings support the theory
279
of proximal bone loading, with a greater degree of proximal bone regeneration seen compared to
280
proximal stress shielding. Older age did not relate to cases with stress shielding, with the mean age
281
of cases that had proximal stress shielding lower than the mean age for those with no change and
282
bone hypertrophy. Proximal bone regeneration was apparent in cases with both an ETO and in
283
cases with a Type III Paprosky femur type, a positive finding supporting the use of this stem in these
284
more complex cases. It is not determinable whether this regeneration relates to structural support in
285
the diaphysis.
286
In cases that required re-revision, the Paprosky femoral classification at re-revision was
287
assessed. The mean time to re-revision was 35 months (range 5 – 96) and as changes in resorptive
288
remodelling are present within the first 6-24 months, sufficient time had elapsed for the development
289
of stress shielding to have occurred [40]. The majority of cases maintained the same Paprosky
290
classification at re-revision, with two cases demonstrating proximal bone regeneration (regression of
291
Paprosky classification). Three of the revision cases had progression of femoral deficiencies, all of
292
which failed to adequately load the proximal bone either due to failure of the HA to bind to the host
293
bone or due to proximal bone insufficiency. A distal fixation type of stem is therefore advised in
13
294
cases with more severe diaphyseal bone loss (Paprosky Type IIIb & IV) [28]. A more complex stem
295
system was required at re-revision in most cases despite no evidence of lysis or progression of the
296
Paprosky classification. This was due to the diaphyseal disruption caused by the periprosthetic/stem
297
fractures. Girdlestone procedures in this series were performed due to infection and non-
298
reconstructable acetabular bone, despite the stem appearing radiologically to have integrated well.
299
The mean OHS of 34 is comparable to outcomes reported in the literature following revision
300
arthroplasty with an uncemented revision stem [41]. Failure to complete follow-up outcome
301
measures at follow-up appointments, most notably for those performed earlier in this series, was the
302
main reason for the number without available PROMS. Pre-operative scores were not available to
303
enable calculation of the change in functional outcome achieved by the revision surgery. Other
304
studies that have looked at patient reported outcomes using the same stem design have reported
305
similar positive scores [18-19]. The lack of PROMS data for over half the cohort is disappointing;
306
however a sample size of 124 still represents the largest published data relating to PROMS for the
307
Corail Revision Stem. We identified a 3% incidence of thigh pain with no radiological evidence to
308
suggest causation from stem positioning/distal hypertrophy in all but one case; revision due to failed
309
ETO union with associated thigh pain. The prevalence of thigh pain in uncemented hip arthroplasty
310
is reported to vary between 1-14% in extensively coated uncemented primary stems [42]. No
311
significant thigh was reported in either of the previous independent studies using the same
312
monoblock, hydroxyapatite coated titanium stem [14, 18].
313
There are limitations within this study. Firstly, the overall follow-up rate of 93% demonstrates a
314
small but important drop-out rate which may have positively biased the findings. Secondly, forty-
315
eight percent of cases reported in this study had less than five year’s minimal radiological follow-up.
316
The reasons for loss to follow-up related largely to patient’s failure to attend arranged appointments.
317
This studies aims were to investigate a number of factors related to revision surgery, not solely
318
survivorship, such as intra-operative issues and radiological changes occurring within five years
319
(subsidence and proximal bone lysis). Failure following revision surgery is demonstrated to occur
320
sooner post-operatively than for primary arthroplasty, and as such we believe the inclusion of cases 14
321
with a minimum one year follow up is justified. A study of 1,100 THA revisions by Springer et al [43]
322
reported a mean time to re-revision of 3.7 years; mean follow-up in our cohort is over 5 years. In
323
order to improve the confidence of our analysis, national (NJR) records were searched relating to
324
each operating surgeon for re-revision procedures conducted. This secondary tier follow-up enables
325
greater confidence in the survivorship; mean follow-up using NJR sourced data is 105 months/8.75
326
years, with over 80% of cases having greater than 5 year follow-up. As we cannot guarantee that all
327
procedures relating to the cases in this study were accurately recorded on the NJR we have classed
328
follow-up time by radiographic evidence of survivorship.
329
In conclusion, this study describes the largest series of cases using the Corail® Revision Stem
330
and found good survivorship, low rates of complications and subsidence, good bone preservation
331
and positive patient reported outcomes. With an aging population and increasing numbers of hip
332
arthroplasties being performed it is important to continue to investigate the outcomes in revision
333
surgery. This study demonstrates that for moderate femoral deficiencies a monoblock, HA-coated
334
titanium stem can be considered a viable option for revision hip arthroplasty and in a significant
335
proportion of cases will allow proximal bone regeneration.
336
15
337
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338
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23. Chang JD, Kim T-Y, Rao MB, Lee S-S, Kim I-S. Revision Total Hip Arthroplasty Using a
396
Tapered, Press-Fit Cementless Revision Stem in Elderly Patients. J Arthroplasty
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398 399
24. Regis D, Sandri A, Bonetti I, Braggion M, Bartolozzi P. Femoral revision with the Wagner tapered stem: a ten- to 15-year follow-up study. Bone Joint Surg Br 2011;93(10):1320-1326 17
400
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402
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403
Complications of Revision Total Hip Arthroplasty with a Mid-Modular Femoral Stem. J
404
Arthroplasty 2015;30(12):2260-2263
405
27. Tyson, Y., Rolfson, O., Kärrholm, J., Hailer, N.P. and Mohaddes, M., 2019. Uncemented or
406
cemented revision stems? Analysis of 2,296 first-time hip revision arthroplasties performed
407
due to aseptic loosening, reported to the Swedish Hip Arthroplasty Register. Acta
408
orthopaedica, pp.1-10.
409 410 411 412 413
28. Cross MB, Paprosky WG. Managing femoral bone loss in revision total hip replacement: fluted tapered modular stems. Bone Joint J 2013;95-B(11A): 95-97 29. Konan S, Garbuz DS, Masri BA, Duncan CP. Non-modular tapered fluted titanium stems in hip revision surgery: gaining attention. Bone Joint J 2014;96-B(11A):56-59 30. Huddleston JI, Tetreault MW, Yu M, Bedair H, Hansen VJ, Choi HR, Goodman SB, Sporer
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SM, Della Valle CJ. Is There a Benefit to Modularity in 'Simpler' Femoral Revisions? Clin
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Orthop Relat Res 2016;474(2):415-420
416
31. Cook, S.D., Barrack, R.L. and Clemow, A.J., 1994. Corrosion and wear at the modular
417
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418
volume, 76(1), pp.68-72.
419
32. Lakstein, D., Eliaz, N., Levi, O., Backstein, D., Kosashvili, Y., Safir, O. and Gross, A.E.,
420
2011. Fracture of cementless femoral stems at the mid-stem junction in modular revision hip
421
arthroplasty systems. JBJS, 93(1), pp.57-65.
422
33. Gromov, K., Bersang, A., Nielsen, C.S., Kallemose, T., Husted, H. and Troelsen, A., 2017.
423
Risk factors for post-operative periprosthetic fractures following primary total hip arthroplasty
424
with a proximally coated double-tapered cementless femoral component. The bone & joint
425
journal, 99(4), pp.451-457.
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34. Frenzel, S., Vécsei, V. and Negrin, L., 2015. Periprosthetic femoral fractures—incidence,
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classification problems and the proposal of a modified classification scheme. International
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orthopaedics, 39(10), pp.1909-1920.
429
35. Singh, J.A., Jensen, M.R., Harmsen, S.W. and Lewallen, D.G., 2013. Are gender,
430
comorbidity, and obesity risk factors for postoperative periprosthetic fractures after primary
431
total hip arthroplasty?. The Journal of arthroplasty, 28(1), pp.126-131.
18
432
36. Huang Y, Zhou Y, Shao H, Gu J, Tang H, Tang Q. What Is the Difference Between Modular
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Arthroplasty 2017;32(10):3108-3113
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37. Palumbo BT, Morrison KL, Baumgarten AS, Stein MI, Haidukewych GJ, Bernasek TL
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Results of revision total hip arthroplasty with modular, titanium-tapered femoral stems in
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severe proximal metaphyseal and diaphyseal bone loss. J Arthroplasty 2013;28(4):690-4
438 439 440 441 442 443 444
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450 451
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452
19
453
Figure Legend:
454
Figure 1. The Corail® Revision Stem with close-up of slots in the distal stem
455
Figure 2 a. Kaplan-Meier survivorship (Revision for any cause): 93.97% at 6 years (CI 90 –
456
98) b.Kaplan-Meier survivorship (aseptic stem revision): 97.33% at 6 years (CI 94 - 100)
457
Figure 3. Bar chart of radiological subsidence
458
Figure 4. Images of the Corail Revision Stem with proximal bone remodelling; (a) pre-operative, (b)
459
post-operative and (c) 10 year follow-up x-rays of a single cases
460 461
Table 1. Primary revision details & stem sizes used at revision
462
Table 2. Details of stem re-revision cases
463
Table 3. Details of cases with post-operative complications
464
Table 4. Bone remodelling outcomes
465
Table 5. Literature review of aspetic stem survivorship in revision arthroplasty
466 467 468
20
Title: Survivorship and radiological analysis of a monoblock, hydroxyapatite coated titanium stem in revision hip arthroplasty Acknowledgements: The lead author’s research assistant role was financially supported by DePuy Synthes.
Table 1. Primary revision details & stem sizes used at revision
Indication for Revision
Cases
Primary Procedure
Cases
Paprosky Classification
Cases
Stem Size Used in Revision
Cases
Aseptic stem loosening
125
Cemented THA
179
Type I
62
10
5
Aseptic cup loosening
61
Un-cemented THA
46
Type II
150
11
11
Infection
18
Cemented hemi-arthroplasty
3
Type III a
39
12
47
Periprosthetic fracture
18
Un-cemented hemi-arthroplasty
6
Type III b
3
13
10
Metal disease
15
Unknown
20
Type IV
0
14
58
Dislocation
9
15
15
Pain
4
16
64
Implant fracture
3
18
26
Pelvic lysis
1
20
11
Unknown
7
Table 2. Details of stem re-revision cases Case Gender
Age (years)
Indication for 1st Revision
Primary THA
Stem Size
Subsidence
Indication for Re-revision
Months to Paprosky Reat 1st / 2nd revision Revision
Stem used in Re-revision
1
Female
59
Infection
Uncemented
15
No measure
Infection
29
1/1
Girdlestone Procedure
2
Female
38
Infection
Cemented
12
< 5mm
Infection
40
2/2
Girdlestone Procedure
3
Male
81
AL
Cemented
14
< 5mm
Infection
43
3A / 3A
C-Stem®AMT
4
Male
61
AL
Cemented
16
< 5mm
Infection
18
3A / 2
Cemented Primary Stem
5
Female
57
AL
Cemented
10
No measure
PF
13
2/2
Reef™ Stem
6
Male
70
AL
Cemented
12
< 5mm
PF
5
2/2
Reef™ Stem
7
Male
85
AL
Cemented
16
< 5mm
PF
10
2/2
Reef™ Stem
8
Male
61
Infection
Cemented
14
< 5mm
PF
29
2/2
Proximal femoral replacement
9
Female
64
AL
Cemented
14
< 5mm
AL
34
2/4
Proximal femoral replacement
10
Male
71
AL
Uncemented
14
< 5mm
AL
96
2 / 3A
C-Stem®AMT
11
Male
61
AL
Cemented
16
5 – 10mm
AL
90
2/1
Unknown*
12
Female
51
Implant Fracture
Uncemented
16
< 5mm
ETO non-union
19
1 / 3B
Reclaim® Modular Revision Stem
13
Male
76
AL
Cemented
18
No measure
Stem fracture
28
3B / 3B
Reef™ Stem
Key: AL = Aseptic loosening, IF = Implant fracture, PF = Periprosthetic fracture. Arrow direction indicates change in Paprosky femoral classification from 1st revision to re-revision; ↔ no change, ↑ increase in Paprosky Classification (worsened), ↓decrease in Paprosky Classification (improved) * Unknown prosthesis used in revision as case referred to another hospital
Table 3. Details of cases with post-operative complications
Periprosthetic Fracture Cases
Subsided Cases
Incidence
9
23
Mean Age
72
70
Female
5 (56%)
8 (35%)
Primary Cemented Cases
8 (4%)
21 (12%)
Primary Uncemented Cases
1 (2%)
2 (4%)
Paprosky Type I
1 (2%)
6 (10%)
Paprosky Type II
6 (4%)
12 (8%)
Paprosky Type III or Higher
2 (5%)
5 (12%)
Table 4. Bone remodelling outcomes
Proximal Stress Shielding
No Change
Proximal Bone Regeneration
8 (4%)
150 (81%)
27 (15%)
71
74
83
Male (104)
66 6 (7%) 2 (2%)
71 62 (77%) 88 (85%)
68 13 (16%) 14 (13%)
Primary Cemented THA (132)
8 (6%)
102 (77%)
22 (17%)
Primary Uncemented THA (38)
0 (0%)
34 (89%
4 (11%)
Wiring In Situ (75)
4 (5%)
58 (77%)
13 (17%)
ETO (24)
1 (4%)
16 (67%)
7 (29%)
Subsidence (17)
1 (6%)
10 (59%)
6 (35%)
Paprosky Type I (40)
1 (2%)
32 (80%)
7 (18%)
Paprosky Type II (113)
5 (6%)
99 (88%)
9 (8%)
Paprosky Type III< (32)
2 (6%)
19 (59%)
11 (34%)
(Total) Cases (185) Mean Follow Up (months) Mean Age (years) Female (81)
Table 5. Literature review of aspetic stem survivorship in revision arthroplasty Author Weeden & Paprosky20 (2002) Trikha et al.21 (2005)
Cases
Stem Type
Femoral Paprosky Classification of Sample
Survivors hip (aseptic)
Follow-Up (years)
170
Extensively porous-coated nonmodular
Type I-IIIC femoral defects
96.5%
14.2
Non-modular HA- coated ceramic
Type I-IIIC femoral defects
100%
10
120
Lamberton et al.22 (2011)
540
Cemented with impaction bone grafting
Not reported
98%
10
Chang et al.23 (2011)
48
Press-fit un-cemented
Type I-IIIA
98%
5.6
Wagner SL
High percentage of Type IIIA< femoral defects
96.6%
13.9
Modular un-cemented
Type I-IIIC femoral defects
97%
7
Regis et al.24 (2011)
41
Pelt et al.25 (2014)
76
Riesgo et al.26 (2015)
161
Modular un-cemented
Type I-IV femoral defects
97.5 %
6.1
Saunders et al.
254
Non-modular HA coated
Type I-IIIB femoral defects
97.3%
6
Figure 1
Survivorship (%)
Figure 2a 100 90 80 70 60 50 40 30 20 10 0 0
Follow-up (years) Number at risk Cumulative success rate Confidence limit (higher) Confidence limit (lower) Standard error
1
2
3
4
5 6 (Years) 7 Follow_up
8
9
10
11
12
0 1 2 3 4 5 6 7 8 9 10 11 12 253.5 237.5 210.5 180 147.5 124 104.5 87 65.5 42.5 23.5 10.5 4 99.61 98.34 96.44 94.78 94.78 93.97 93.97 92.82 88.24 83.53 70.77 70.77 70.77 100 100 99 98 98 98 98 98 96 94 86 94 108 99 97 94 92 91 90 90 88 81 73 55 48 33 0.004 0.008 0.013 0.016 0.018 0.021 0.023 0.027 0.037 0.052 0.079 0.118 0.191
Survivorship (%)
Figure 2b
100 90 80 70 60 50 40 30 20 10 0 0
Follow-up Number at risk Cumulative success rate Confidence limit (higher) Confidence limit (lower) Standard error
0 254 99.61 100 99 0.004
1
2
1 237 98.76 100 97 0.007
3
2 210 97.33 99 95 0.011
4
5 6 7 Follow-Up (Years)
8
9
10
3 4 5 6 7 8 178.5 147.5 123.5 104.5 87.5 64 97.33 97.33 97.33 97.33 95.05 95.05 100 100 100 100 99 100 95 95 95 94 91 90 0.012 0.013 0.014 0.016 0.023 0.026
11
12
9 41.5 95.05 101 89 0.033
10 11 12 22.5 10.5 4 90.60 90.60 90.60 102 107 118 79 74 63 0.059 0.086 0.139
Figure 3
Subsidence 250
Cases
200
195
150 100 50
17
6
0 < 5 mm
5 - 10 mm Degree of Subsidence
> 10 mm
Figure 4 a / b / c
a.
b.
c.
Figure Legend: Figure 1. The Corail® Revision Stem with close-up of slots in the distal stem Figure 2 a. Kaplan-Meier survivorship (Revision for any cause): 93.97% at 6 years (CI 90 – 98) b.Kaplan-Meier survivorship (aseptic stem revision): 97.33% at 6 years (CI 94 - 100) Figure 3. Bar chart of radiological subsidence Figure 4. Images of the Corail Revision Stem with proximal bone remodelling; (a) preoperative, (b) post-operative and (c) 10 year follow-up x-rays of a single cases Table Legend: Table 1. Primary revision details & stem sizes used at revision Table 2. Details of stem re-revision cases Table 3. Details of cases with post-operative complications Table 4. Bone remodelling outcomes Table 5. Literature review of aspetic stem survivorship in revision arthroplasty