Revision Total Hip Arthroplasty With a Modular Cementless Femoral Stem

    Revision Total Hip Arthroplasty with a Modular Cementless Femoral Stem Christopher Pelt MD, Wes Madsen MD, Jill Erickson PA-C, Jeremy Gililland MD, Michael Anderson MS ATC, Christopher Peters MD PII: DOI: Reference:

S0883-5403(14)00300-3 doi: 10.1016/j.arth.2014.04.042 YARTH 53967

To appear in:

Journal of Arthroplasty

Received date: Revised date: Accepted date:

17 October 2013 16 April 2014 29 April 2014

Please cite this article as: Pelt Christopher, Madsen Wes, Erickson Jill, Gililland Jeremy, Anderson Michael, Peters Christopher, Revision Total Hip Arthroplasty with a Modular Cementless Femoral Stem, Journal of Arthroplasty (2014), doi: 10.1016/j.arth.2014.04.042

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Revision Total Hip Arthroplasty with a Modular Cementless Femoral Stem

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University of Utah Orthopaedic Center 590 Wakara Way Salt Lake City, Utah 84108

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Christopher Pelt MD, Wes Madsen MD, Jill Erickson PA-C, Jeremy Gililland, MD, Michael Anderson MS ATC and Christopher Peters MD

Corresponding Author: Christopher E. Pelt, MD Assistant Professor, Orthopaedic Surgery University of Utah Department of Orthopaedics 590 Wakara Way Salt Lake City, UT 84108 801-587-5448 (w) 801-587-5411 (f) [email protected]

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ACCEPTED MANUSCRIPT Abstract We retrospectively reviewed 123 patients who underwent cementless THA with modular femoral stem

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designs for revision THA or conversion of failed ORIF and found 75 patients available for analysis. The Harris Hip Score (HHS) improved from 52 ± 14 to 86 ± 11 (p<0.001). The femoral stem was re-revised in

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eight patients (11%). The mean time to re-revision was 1.1 years (0.13 – 2.54). Reasons for re-revision included infection (n=5, 7%), aseptic loosening (n=2, 3%) and significant pain (n=1, 1%). There were no

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failures of the modular junctions. PC stems had an increased rate of intraoperative fractures (PC 28% vs. STS 9%, p=0.04). Modular cementless femoral stems provide acceptable mid-term results in revision

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THA.

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Key Words: total hip arthroplasty, revision total hip arthroplasty, cementless femoral stem, modular

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femoral stem

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ACCEPTED MANUSCRIPT Introduction The number of revision THA is increasing every year[1, 2]. The management of proximal femoral bone

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loss during revision total hip arthroplasty (THA) remains challenging. A variety of implant options are available, including long cemented stems, monoblock cementless porous stems, monoblock fluted

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tapered stems, impaction grafting and modular cementless femoral stems. Most of these modular cementless stems have only been available for the past 10-15 years and mid-term follow up outcomes

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are important as we evaluate the efficacy of this technology.

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Many modular cementless revision stems are available with varied surface coatings and with or without anti-rotation splines. Advantages of modular stems during revision include improved intra-operative

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ability to restore leg length, offset and femoral version[3, 4]. Reports have expressed concerns of the potential for failure at the modular junction and stem fracture[5]. However, there are few published

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studies reporting the early to mid-term outcomes of revision THA performed with this type of stem [6-

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9]. We sought to analyze the clinical and radiologic outcomes of patients who underwent revision THA with proximal femoral bone loss using modular cementless femoral stems.

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Materials and Methods

Patients and surgical procedure After IRB approval, we performed a retrospective review of our institutional database and electronic medical record. This yielded 123 consecutive patients who underwent revision total hip arthroplasty or reoperation of previous hip surgery [n=5, failed open reduction and internal fixation (ORIF) of proximal femoral fractures] with a cementless modular femoral stem design (Mallory/Head®, Biomet, Warsaw, IN, USA) from 1997 to 2009 by a single surgeon at our tertiary academic medical center. The Mallory/Head® (Biomet, Warsaw, IN, USA) modular femoral body design was used with both PC and STS

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ACCEPTED MANUSCRIPT stems (Figure 1). Both stem designs underwent manufacturing design improvements during the study period to add roller-hardened tapers that mate with the proximal body with additional screw fixation

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after taper engagement by impaction. The PC stem is a titanium diaphyseal engaging stem with plasma

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porous spray coating and a coronal slot distally. STS design is a titanium diaphyseal engaging grit blasted splined tapered stem. The proximal body of the Mallory/Head® design does include a medial calcar

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buildup available at different resection levels for each of five different body sizes.

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Of the 123 patients, 16 died and 32 were lost to followup prior to two years and had not undergone revision of the femoral stem, these patients were removed from the analysis. This resulted in a total of

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75 patients available for review (Figure 2). For patients who were unable to return for follow up, we attempted to contact them via telephone and mail surveys to obtain information such as implant

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survival, infection, dislocation, reoperations and other complications. Additionally, we reviewed the

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social security death index for all patients. For patients who had less than a two-year followup, or who

followup.

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were deceased, we attempted to contact the referring or local orthopaedic surgeon to obtain further

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Indications for surgery were aseptic loosening (53), infection (8), periprosthetic fracture (7), failed ORIF (4), dislocation (2) and chronic pain (1). Eighteen patients received a porous coated (PC) stem and 57 received a splined tapered straight (STS) stem. A posterolateral approach was used in all but 8 cases due to previous anterolateral approach. An extended trochanteric osteotomy was used when needed to facilitate existing implant removal. Postoperatively patients were routinely partial weight bearing with crutches or walker for support for 6 weeks, after which all patients were allowed to progress to full weight bearing as tolerated. Standard clinical follow up was scheduled at 2 weeks, 6 weeks, 6 months, 1 year and every 2 years thereafter. Radiographs were performed at all clinical follow up visits except 2 weeks and in the post-anesthesia care unit.

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ACCEPTED MANUSCRIPT Outcome assessment The following variables were included for analysis: patient demographics, Harris Hip Scores (HHS),

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preoperative femoral bone defects (classified according to the system of Mallory[10]), operative details, postoperative radiolucencies, subsidence, complications and re-revision. Patient demographics and

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operative details were obtained by retrospective review of the electronic medical record. Harris Hip scores were obtained preoperatively and at subsequent follow up visits. All available preoperative and

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postoperative radiographs were reviewed. Femoral bone loss prior to surgery was graded using the Mallory classification[10]. Radiographic review included analysis of the seven Gruen zones [11] on the

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anteroposterior radiograph for postoperative evidence of radiolucencies. All radiographs were calibrated using the known head size and subsidence measurements were made whenever possible as

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Statistical analysis

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described by Engh[12].

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All data are presented as mean ± standard deviation unless otherwise specified. Wilcoxon Signed Rank analysis was used to assess outcomes data pre and post-operatively. A Wilcoxon-Mann-Whitney test

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was used to assess differences in subsidence between revised and non-revised stems and PC versus STS stems. Chi-square or Fisher’s exact test, when expected frequencies were not adequate for the Chisquare test, were used for the analysis of binary data. The data were analyzed using commercially available statistical software (Stata version 13, College Station, TX, USA). Results Baseline demographic and clinical findings are noted in Table 1. Mean follow up was 7 years (range 1 to 17 years, Figure 3). HHS improved from a pre-operative mean of 52 ± 14 (95% CI 46 – 58) to postoperative mean of 86 ± 11 (95% CI 82 – 91)(p<0.001).

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ACCEPTED MANUSCRIPT Revision of the femoral stem occurred in eight patients (11%). The mean time to revision was 1.1 years (0.13 – 2.54). Reasons for re-revision included infection in five patients (7%), aseptic loosening in two

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patients (3%) and one patient (1%) was revised for significant pain at an outside facility. Both patients

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who failed for aseptic loosening had STS stems and had Mallory grade of IIIC or IIIB preoperatively

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(Figure 4). They were revised at 24 months and 2 months, respectively.

There was no difference in femoral bone loss in patients with aseptic loosening and those without

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(p=0.18). There were no failures of the modular taper junction. Subsidence was greater in stems that went on to require re-revision than those that did not (3mm vs. 1mm, p=0.01), and not surprisingly also

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more in failures due to aseptic loosening (6mm vs. 1mm, p=0.02). There was no evidence of progressive radiolucent lines on radiographs for any patient (Figure 5). We also found no difference in the amount of

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subsidence between PC and STS stems (1mm vs. 1mm, p=0.88). Intraoperative complications included

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fractures (Table 2) and two cases of intraoperative bleeding. Post-operative complications included early and late postoperative infections, hematomas, dislocations, wound dehiscence, aseptic loosening and

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others (Table 3). There were more intraoperative fractures inserting PC stems compared to STS designs

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(PC, 5 (28%) vs. STS, 5 (9%) p=0.04). Our cohort demonstrated a high overall mortality of 42% (n=52). The average time to death was 3.5 years (range, 3 days - 10 years). Deceased patients were significantly older than those who survived (p<0.001), with a mean age of 76 (95% CI 73 – 79) versus a mean age of 66 (95% CI 62 – 70). Sixteen patients died prior to two years and to our knowledge had maintained the femoral stem. These 16 patients had a mean followup of 6 months (range, 3 days to 1.6 years). The mean time to death was 8.4 months (range, 3 days to 1.8 years). There were 7 males (44%) and 9 females (56%). They had a mean age of 74 ± 15 years (range, 39-90) and a mean BMI of 33.4 ± 5.40 kg/m2. Seven patients had PC stems and nine patients had STS stems. There was no difference in subsidence between the stems (p=0.91).

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ACCEPTED MANUSCRIPT None of these patients had evidence of progressive radiolucencies. There was little evidence of subsidence with an overall mean subsidence of 0.08mm ± 0.11mm (range 0mm – 0.3mm) at last follow

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of the femoral stem as failures, our failure rate would be 20% (24/123).

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up. If we consider the patients who died prior to two years as well as those that underwent re-revision

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There were 36 patients who died after two years with a mean followup of 2.84 years (range, 6 weeks – 10 years). Of these, 22 were males and 14 were females. They had a mean age of 76 years (range, 53-

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88). The mean BMI was 28.52 ± 6.89 kg/m2. Eight patients had PC stems and 28 had STS stems. There was no difference in subsidence between the stems (p=0.35). None of these patients had evidence of

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progressive radiolucencies. There was little evidence of subsidence with an overall mean subsidence of 0.40mm ± 0.70mm (range 0mm – 2.3mm) at last follow up. To our knowledge, none of these patients

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had revision of the stem prior to death.

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A review of the 32 patients that were ultimately deemed lost to followup demonstrated an average

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followup of 6 months (range, 3 days – 19 months). There were 13 males and 19 females and the average age was 74 ± 14 (range, 43 – 97). These patients had an average BMI of 28.08 ± 6.9 kg/m2. Eight

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had a PC Stem and 24 received a STS design. There was no difference in subsidence between the stems (p=0.86) and only a small amount of subsidence was evident at last followup (0.51mm ± 1.22mm, range 0 – 6.1mm). An overall failure rate, including patients that died or were lost to followup prior to two years and those that underwent re-revision of the femoral stem was found to be quite high at 46%. Discussion There have been several reports on the early to mid-term outcomes of modular cementless femoral revision components[6-9, 13-21]. The majority of these show similar results with survival rates around 90%. We report on a cohort of 123 patients who underwent cementless THA with a modular femoral stem design for revision THA or conversion of failed ORIF and found 75 patients available for analysis

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ACCEPTED MANUSCRIPT with an overall failure rate at a mean 7 years of 11% for all cause failure and 3% for aseptic loosening. Importantly, with this design, no failures of the modular junction were seen.

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Limitations of this study are primarily related to the retrospective study design. All background clinical and operative data were obtained retrospectively by means of a review of our prospective institutional

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database and electronic medical records. Despite attempts at prospective followup, thirty-two patients

evaluating differences between historic controls.

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(26%) were ultimately deemed lost to follow up. In addition, the sample size was too small to preclude

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This study had a very high mortality rate during the given follow up interval with 52 deaths out of the initial cohort of 123 patients. This in part may be due to the fact that many of these patients were older

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(p<0.001) and have multiple medical comorbidities. Many of these patients were referred to our facility not only because of the complexity of the surgery but often also due to the poor health status of the

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patients. However, none of these deaths were known to be due to the revision THA surgery. This study

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was not designed to detect why the mortality was so high. Recently, there has been some literature describing the increased mortality associated with revision total hip arthroplasty that is often

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overlooked[22]. Our data corroborate this finding. The intra-operative fracture rate of 13% noted in this study was similar to previous studies, with reported rates of 3-18%[16, 18, 21, 23]. We commonly use wires to help prevent iatrogenic fracture when operating for periprosthetic fractures or in the setting of an extended trochanteric osteotomy, but as can be seen in this series, intra-operative fractures still occur despite this prophylaxis. There were no cases of modular tapered junction or femoral stem fractures in our series. Other modular stems have shown failure most often at the modular junction[5, 24-26]. This problem seems to have decreased with thicker modular junctions and improved metallurgy, including a roller hardened taper, as evidenced by the lack of any modular junction failures in our series. Further, the design of the

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ACCEPTED MANUSCRIPT Mallory/Head® (Biomet, Warsaw, IN, USA) includes a calcar body build up that could offer additional medial column support and decrease varus stress and potentially further mitigate the risk modular

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junction failure. The overall failure rate in this series of 11% is similar to that previously reported by other groups for

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modular cementless femoral revision components[6-9]. The most common reasons for failure in our study were infection and aseptic loosening. The stems that loosened seemed to be in patients with

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more severe bone loss but our numbers were too few for this to show statistical significance (p=0.18). Of interest, we did not see higher failures of our porous coated stems in higher degrees of bone loss,

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unlike what has been reported in previous series of fully porous coated monoblock stems[27].

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In summary, revision THA with the use of a modular cementless femoral component affords favorable mid-term results with an aseptic failure rate of only 3% at 7 year follow-up. STS stems resulted in fewer

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intraoperative fractures but a higher rate of aseptic loosening in the setting of increased bone loss

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(Mallory IIIB and IIIC). Of interest, there were no stem modular junction fractures seen in this series.

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Modular cementless femoral stems provide acceptable mid-term results in the setting of revision THA.

Acknowledgments The authors thank Nadia Hamad, MS ATC and Laura Juarez, MPH for their assistance in this study.

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ACCEPTED MANUSCRIPT References:

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1. Kurtz S, Ong K, Lau E, Mowat F, Halpern M. Projections of primary and revision hip and knee arthroplasty in the United States from 2005 to 2030. The Journal of bone and joint surgery American volume 89(4): 780, 2007 2. Iorio R, Robb WJ, Healy WL, Berry DJ, Hozack WJ, Kyle RF, Lewallen DG, Trousdale RT, Jiranek WA, Stamos VP, Parsley BS. Orthopaedic surgeon workforce and volume assessment for total hip and knee replacement in the United States: preparing for an epidemic. The Journal of bone and joint surgery American volume 90(7): 1598, 2008 3. Jones RE. Modular revision stems in total hip arthroplasty. Clinical orthopaedics and related research (420): 142, 2004 4. Sporer SM, Paprosky WG. Femoral fixation in the face of considerable bone loss - The use of modular stems. Clinical orthopaedics and related research (429): 227, 2004 5. Lakstein D, Eliaz N, Levi O, Backstein D, Kosashvili Y, Safir O, Gross AE. Fracture of cementless femoral stems at the mid-stem junction in modular revision hip arthroplasty systems. The Journal of bone and joint surgery American volume 93(1): 57, 2011 6. Jibodh SR, Schwarzkopf R, Anthony SG, Malchau H, Dempsey KE, Estok DM, 2nd. Revision Hip Arthroplasty with A Modular Cementless Stem: Mid-Term Follow Up. The Journal of arthroplasty, 2012 7. Munro JT, Garbuz DS, Masri BA, Duncan CP. Role and results of tapered fluted modular titanium stems in revision total hip arthroplasty. The Journal of bone and joint surgery British volume 94(11 Suppl A): 58, 2012 8. Palumbo BT, Morrison KL, Baumgarten AS, Stein MI, Haidukewych GJ, Bernasek TL. Results of revision total hip arthroplasty with modular, titanium-tapered femoral stems in severe proximal metaphyseal and diaphyseal bone loss. The Journal of arthroplasty 28(4): 690, 2013 9. Klauser W, Bangert Y, Lubinus P, Kendoff D. Medium-term follow-up of a modular tapered noncemented titanium stem in revision total hip arthroplasty: a single-surgeon experience. The Journal of arthroplasty 28(1): 84, 2013 10. Mallory TH. Preparation of the proximal femur in cementless total hip revision. Clinical orthopaedics and related research (235): 47, 1988 11. Gruen TA, McNeice GM, Amstutz HC. "Modes of failure" of cemented stem-type femoral components: a radiographic analysis of loosening. Clinical orthopaedics and related research (141): 17, 1979 12. Engh CA, Massin P, Suthers KE. Roentgenographic assessment of the biologic fixation of poroussurfaced femoral components. Clinical orthopaedics and related research (257): 107, 1990 13. Wirtz DC, Heller KD, Holzwarth U, Siebert C, Pitto RP, Zeiler G, Blencke BA, Forst R. A modular femoral implant for uncemented stem revision in THR. International orthopaedics 24(3): 134, 2000 14. Sporer SM, Paprosky WG. Revision total hip arthroplasty: the limits of fully coated stems. Clinical orthopaedics and related research (417): 203, 2003 15. Berry DJ. Treatment of Vancouver B3 periprosthetic femur fractures with a fluted tapered stem. Clinical orthopaedics and related research (417): 224, 2003 16. Kwong LM, Miller AJ, Lubinus P. A modular distal fixation option for proximal bone loss in revision total hip arthroplasty: a 2- to 6-year follow-up study. The Journal of arthroplasty 18(3 Suppl 1): 94, 2003 17. Emerson RH, Jr. Proximal ingrowth components. Clinical orthopaedics and related research (420): 130, 2004 18. Schuh A, Werber S, Holzwarth U, Zeiler G. Cementless modular hip revision arthroplasty using the MRP Titan Revision Stem: outcome of 79 hips after an average of 4 years' follow-up. Archives of orthopaedic and trauma surgery 124(5): 306, 2004

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19. Murphy SB, Rodriguez J. Revision total hip arthroplasty with proximal bone loss. The Journal of arthroplasty 19(4 Suppl 1): 115, 2004 20. Mumme T, Muller-Rath R, Weisskopf M, Andereya S, Neuss M, Wirtz DC. [The cement-free modular revision prosthesis MRP-hip revision stem prosthesis in clinical follow-up]. Zeitschrift fur Orthopadie und ihre Grenzgebiete 142(3): 314, 2004 21. Hinrichs F, Boudriot U, Hunerkopf M, Griss P. [Design and first clinical results with the ZMR taper revision prosthesis]. Zeitschrift fur Orthopadie und ihre Grenzgebiete 143(3): 355, 2005 22. Choi H-R, Beecher B, Bedair H. Mortality after septic versus aseptic revision total hip arthroplasty: a matched-cohort study. The Journal of Arthroplasty 28(8 Suppl): 56, 2013 23. Meek RM, Garbuz DS, Masri BA, Greidanus NV, Duncan CP. Intraoperative fracture of the femur in revision total hip arthroplasty with a diaphyseal fitting stem. The Journal of bone and joint surgery American volume 86-A(3): 480, 2004 24. Lakstein D, Backstein D, Safir O, Kosashvili Y, Gross AE. Revision total hip arthroplasty with a porouscoated modular stem: 5 to 10 years follow-up. Clinical orthopaedics and related research 468(5): 1310, 2010 25. Busch CA, Charles MN, Haydon CM, Bourne RB, Rorabeck CH, Macdonald SJ, McCalden RW. Fractures of distally-fixed femoral stems after revision arthroplasty. The Journal of bone and joint surgery British volume 87(10): 1333, 2005 26. Van Houwelingen AP, Duncan CP, Masri BA, Greidanus NV, Garbuz DS. High survival of modular tapered stems for proximal femoral bone defects at 5 to 10 years followup. Clinical orthopaedics and related research 471(2): 454, 2013 27. Sporer SM, Paprosky WG. Revision total hip arthroplasty: the limits of fully coated stems. Clinical Orthopaedics and Related Research (417): 203, 2003

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Figure Legend

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Figure 2. A flow chart demonstrating the attrition of the cohort

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Figure 1. Mallory-Head proximal body (Top) with STS (bottom left) and PC (bottom right) stem options

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Figure 3. Histogram of the followup of the final cohort (n=75)

Figure 4.

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a. The radiograph shows the pre-operative film with asymmetric polyethylene wear in the cup and a cemented femoral stem with severe osteolysis and cortical thinning. b. The radiograph shows acute post-operative radiograph with a revised polyethylene and femoral components. c. The radiograph shows obvious subsidence of the femoral component that went on to a re-revision for aseptic failure (radiograph not shown).

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Figure 5. Follow up radiograph 9.2 years after surgery showing no signs of radiolucency with proximal and distal bone ingrowth.

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Fig. 1

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ACCEPTED MANUSCRIPT Table 1: Baseline demographic and clinical data between stem designs. PC Stems n=18

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Gender, n (%) Male Female Age (years) mean ± sd 95 % CI

STS Stems n=57 25 (44%) 32 (56%)

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71 ± 12 66 – 77

66 ± 15 62 – 70

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29.0 ± 6.12 25.47 – 32.53

29.77 ± 7.00 27.49 – 32.06

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1 (6%) 2 (11%) 3 (17 %) 3 (17%) 9 (50%)

11 (19%) 23 (40%) 7 (12%) 3 (5%) 13 (22%)

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12 (67%) 6 (33%)

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BMI, (kg/m ) mean ± sd 95 % CI Mallory classification Femoral bone loss, n (%) Type I Type II Type IIIA Type IIIB Type IIIC

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Variable

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ACCEPTED MANUSCRIPT Table 2: Intra-operative Fractures

10 (13%) 6 (60%) 3 (30%) 1 (10%)

STS Stems

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5 (28%) 4 (80%) 0 (0%) 1 (20%)

5 (9%) 2 (40%) 3 (60%) 0 (0%)

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Overall Fracture Greater Trochanter Femoral Shaft Sub-Trochanteric

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n (%)

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Intra-Operative Fractures

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n (%) 4 (5%) 3 (4%) 3 (4%) 3 (4%) 2 (3%) 2 (3%) 2 (2%) 1 (1%) 1 (1%) 1 (1%) 1 (1%)

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Postoperative Complications Dislocation Hematoma without I&D Subsequent Acetabular Revision Nerve Palsy Periprosthetic Fracture Wound Dehiscence Chronic Groin Pain Lesser trochanteric migration Subdural hematoma s/p fall Urinary tract infection Renal failure

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Table 3: Post-operative complications.

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