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Periprosthetic fracture in the elderly with anatomic modular cementless hemiarthroplasty
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Original article
Periprosthetic fracture in the elderly with anatomic modular cementless hemiarthroplasty P. Kouyoumdjian a,∗ , A. Dhenin a , A. Dupeyron b , R. Coulomb a , G. Asencio a a b
Service de chirurgie orthopédique et traumatologique, hôpital Carémeau, CHU de Nîmes, place de Pr-R.-Debré, 30000 Nîmes, France Service de médecine physique et réadaptation, CHU de Nîmes, hôpital Carémeau, place de Pr-R.-Debré, 30000 Nîmes, France
a r t i c l e
i n f o
Article history: Received 15 November 2015 Accepted 10 May 2016 Keywords: Periprosthetic fracture Hemiarthroplasty Hip Cementless stem Osteoporosis
a b s t r a c t Background: The use of an anatomic cementless stem in hemiarthroplasties for femoral intracapsular proximal fracture has been debated, notably because of bone weakness and/or morphological defects related to osteoporosis. We therefore conducted a retrospective study in subjects over 75 years of age who had received an anatomic stem partially coated with hydroxyapatite. The objectives were to determine: 1) the incidence of periprosthetic fractures (PPFs) and, 2) the influence of anatomic factors, including the Cortical Bone Ratio (CBR) (the relation between the endosteal and external diameter of the femoral diaphysis 10 cm below the lesser trochanter). Hypothesis: The risk of PPF with an anatomic cementless implant is greater than with cemented stems. Material and methods: We retrospectively analyzed 233 patients followed up for 5 years after their surgery. The stem used was an anatomic stem with a modular neck partially coated with hydroxyapatite. The risk factors examined were age, gender, history of osteoporotic fractures, diverse causes of secondary osteoporosis, and proximal bone stock according to various referenced radiological indices such as the CBR. Results: Twenty patients (15%) were lost to follow-up, 74 had died (32%) but did not undergo revision for PPF, 15 of the 139 survivors at the last follow-up (10.8%) had had a PPF, five (3.6%; four females, one male) were early fractures (≤ 2 months after implantation), ten (7.2%; two females, eight males) were late fractures (> 2 months). Male gender was protective for PPF occurrence (RR = 0.129; 95%CI (0.04–0.39); P = 0.0003), whereas secondary factors of osteoporosis (RR = 2.035; 95%CI (1.11–3.72); P = 0.0211), and CBR > 0.49 (RR = 227.42; 95%CI (1.072–48,226.76); P = 0.0471) were found as risk factors of PPF. Discussion: The PPF rate was greater than that related to cemented stems, requiring that morphological and clinical factors of bone weakness (collected with the patient history and related to osteoporosis) be taken into account. A CBR > 0.49 requires caution on the use of this type of stem. Level of evidence: Level 4. Retrospective study. © 2016 Elsevier Masson SAS. All rights reserved.
1. Introduction The results of hemiarthroplasty in the treatment of femoral neck fractures in the elderly patient are conditioned by the quality of the surgical technique, as well as the type of implant and fixation [1,2]. Berend et al. [3] showed that the rates of periprosthetic fractures (PPFs) after total hip arthroplasty (THA) were greater after implantation of cementless stems (6.4%) versus cemented stems (2.3%). Lindahl et al. [4] reported a rate increasing from 0.3% PPFs for cemented stems to 5.4% for cementless stems.
∗ Corresponding author. Tel.: +33603998081; fax: +33466218057. E-mail address: [email protected] (P. Kouyoumdjian).
Today, PPFs are indeed one of the leading causes of THA complications [2–4]. According to the Swedish Total Hip Replacement Register [5], the annual incidence increases with time and varies between 0.045 and 0.13%. This is a serious and frequent complication whose morbidity varies between 8.7 and 22.9% depending on the series, and mortality is estimated by Laffargue et al. [6] and Lindahl et al. [7] at 9.8%. Other than the modifications of the bone matrix related to osteopenia, the risk factors of PPF that have been identified are age [7] and osteoporosis [8]. However, modifications in the shape of the medullary canal related to aging have not been evaluated in this situation [6–8]. In a group of subjects older than 75 years treated for intracapsular femoral neck fracture with cementless with an anatomic stem partially coated with hydroxyapatite, we conducted a retrospective study aiming to determine 1) the rate of PPFs and 2) the
http://dx.doi.org/10.1016/j.otsr.2016.05.013 1877-0568/© 2016 Elsevier Masson SAS. All rights reserved.
Please cite this article in press as: Kouyoumdjian P, et al. Periprosthetic fracture in the elderly with anatomic modular cementless hemiarthroplasty. Orthop Traumatol Surg Res (2016), http://dx.doi.org/10.1016/j.otsr.2016.05.013
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influence of anatomic factors using the Cortical Bone Ratio (CBR). We hypothesized that the risk of PPF with this type of implant would be greater, notably compared to the studies reported in the literature on cemented stems. 2. Material and methods 2.1. Patients We retrospectively analyzed a continuous, single-center series between January 2002 and December 2004, made up of 287 patients aged 75 years or older who had presented an intracapsular femoral neck fracture at the proximal end of the femur treated with hip hemiarthroplasty via the posterolateral approach. The following were excluded from the study (Fig. 1): bedridden patients, pathological femoral neck fractures, cemented arthroplasties (intraoperative choice given subjective evaluation of bone weakness), and revisions of these arthroplasties for reasons other than PPF (infection, instability, osteosynthesis revision by stem reconstruction or cemented stem); none of these cases had PPF.
This series comprised 233 healthy (Parker score > 6) cases with a mean age of 84.6 years (range, 75–101 years), including 168 females (72.1%) and 65 males (27.8%). The implant used in all cases was an anatomic MBATM stem (Lépine, Genay, France) with the proximal third coated with hydroxyapatite (Fig. 2), including a modular neck with two Morse tapers associated with a stainless steel head and a mobile cup. One hundred thirty-nine patients were followed with a minimum follow-up of 5 years, 74 patients (32%) had died (two in the first 2 months after surgery), and 20 patients (15%) were lost to follow-up. None of the deaths were directly related to the arthroplasty, notably none were related to a PPF. A total of 139 patients (109 females [78.4%] and 30 males [21.6%]), with a mean age at implantation of 84 years (range, 75–100 years), were seen with a minimum follow-up of 5 years (Fig. 1). 2.2. Assessment methods Several criteria were investigated: age, gender, osteoporosisrelated risk factors, and radiological morphological criteria related to possible bone weakness. This study analyzed the following
Fig. 1. Flowchart of the series.
Please cite this article in press as: Kouyoumdjian P, et al. Periprosthetic fracture in the elderly with anatomic modular cementless hemiarthroplasty. Orthop Traumatol Surg Res (2016), http://dx.doi.org/10.1016/j.otsr.2016.05.013
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◦ the Canal Flare Index (CFI), the relationship between the endosteal diameter measured 10 cm below the lesser trochanter and the diameter measured 2 cm above. Measurements were taken using the Osirix v.3.8 32 bitTM software (Geneva, Switzerland). The lower Morse taper of the stem’s modular neck (12 mm) was used as the reference for scaling. 2.3. Statistical analysis
Fig. 2. MBA prosthesis (Lépine, Genay, France). Radiographic indices measured [10]: A: endosteal diameter 2 cm above the lesser trochanter; B: external diameter of the femur at the lesser trochanter; C: endosteal diameter of the femur at the lesser trochanter; D: endosteal diameter 7 cm below the lesser trochanter; E: endosteal diameter 10 cm below the lesser trochanter; F: external diameter of the femur 10 cm below the lesser trochanter. Dorr’s Canal Calcar Ratio (CCR) equal to E/C; Noble’s Canal Flare Index (CFI) equal to A/E; Spotorno’s Morphological Cortical Index (MCI) equal to B/D; Cortical Bone Ratio (CBR) equal to E/F.
risk factors of osteoporosis-related bone weakness: a history of dysthyroidism, hypercorticism, rheumatoid arthritis, ankylosing spondylitis, chronic inflammatory digestive diseases, thyroid or corticoid hormone treatments, chemotherapies, and a history of osteoporotic fractures (distal radius, proximal humerus, spinal cord, proximal contralateral femur). All PPFs were assessed for frequency, time to occurrence, and type (SOFCOT modified Vancouver classification [9]). Early PPFs were considered as occurring intraoperatively and during the 2 months following surgery; beyond this time they were considered late fractures. The radiographic analysis was performed by three independent observers and three times for each of them. The radiological indices for proximal femur bone weakness described in the literature [10] and measured on the postoperative image were (Fig. 2): • the index of diaphyseal cortical bone thinning: the CBR, the relationship between the endosteal and external diameter of the femoral diaphysis 10 cm below the lesser trochanter; • the index of metaphyseal cortical bone thinning: the Morphological Cortical Index (MCI), the relationship between the external diameter of the femur at the lesser trochanter and the endosteal diameter 7 cm below; • proximal femur indices such as: ◦ the relationship between the femoral endosteal diameter 10 cm below and the diameter at the lesser trochanter, or the Canal Calcar Ratio (CCR),
A Cox multivariate model with adjusted logistical regression was used to model the time to PPFs’ occurrence. Implant survival, as related to the occurrence of a PPF and depending on gender, was assessed using the Kaplan-Meier method. Evaluation of the risk of PPF occurrence depending on gender was determined using the Logrank test. The risk of fracture for each additional secondary osteoporosis risk factor was determined using the Cochran-Armitage test for trend. The age for which the risk of fracture was the greatest was assessed using cluster analysis. The results were considered significant if P < 0.05. Inter- and intraclass concordance of the radiographic indices were evaluated using the Lin concordance correlation coefficient. 3. Results We found very good reproducibility of the measurements for the indices measured. The CBR was the most reproducible index in this study (Table 1). At the last follow-up (78 months; range, 62–108 months), 15 PPFs (nine males and six females; 10.8% of the patients) had occurred. The mean age at injury was 84.5 years (range, 78–100 years). There were four Ag fractures and 11 B2 fractures. Early PPFs (0–32 days) occurred in five patients (four females and one male), with a mean age of 80.8 years (range, 78–86 years) at the time of injury, with one intraoperative PPF and the others secondary to a fall. Ten patients (eight males and two females), a mean 86.3 years old (range, 83–90 years) at the time the index fracture occurred, presented a late PPF with a mean time to injury of 17 months (range, 8–60 months). Age did not appear to be a risk factor. Thirty-two patients (23%) presented at least one of the above-mentioned risk factors for secondary osteoporosis. The presence of at least one risk factor reported in the patient’s history and classified at the same level was noted as a significant predictive factor of both early and late PPF (RR = 1.74; 95%CI (0.983–3.08); P = 0.0211). The accumulation of risk factors for osteoporosis considerably increased the risk of PPF (RR = 2.035; 95%CI (1.11–3.72); P = 0.088): 8.3% for one, 18% for two, and 100% for three risk factors. Male gender was protective against early PPF (RR = 0.129; 95%CI (0.04–0.39); P = 0.0003). On the other hand, the analysis of survival curves according to gender showed a greater risk of late PPF in males (P = 0.0001) (Fig. 2). Of the radiological indices measured, only the CBR was found to be determinant (Table 2). In reference to the threshold value reported by Yeung et al. [10], we noted an increased risk of PPF for a CBR > 0.49 (RR = 227.42; 95%CI (1.072–48226.76)). In the “less
Table 1 Lin’s inter- and intraobserver concordance correlation coefficient (CCC) for the different radiological variables calculated. Interobserver CCC Inter-CCC Canal Calcar Ratio Canal Flare Index Morphological Cortical Index Cortical Bone Ratio
0.975 0.986 0.978 0.999
Intraobserver CCC Range 0.974–0.9776 0.984–0.988 0.976–0.99 0.998–0.999
Intra-CCC 0.981 0.984 0.980 0.999
Range 0.973–0.998 0.981–0.997 0.941–0.997 0.990–0.999
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Table 2 Mean and standard deviation of different radiological variables. Variable
All subjects (n = 139)
Cortical Bone Ratio Canal Calcar Ratio Canal Flare index Morphological Cortical Index Neck-head angle
0.53 0.52 3.11 2.37 135.88
± ± ± ± ±
0.08 (0.32–0.79) 0.12 (0.34–0.88) 0.68 (1.49–4.73) 0.42 (1.36–3.53) 4.89 (122–148)
No fracture at follow-up (n = 124) 0.57 0.52 3.13 2.38 135.61
than or equal to 0.49” group, the PPF rate was 5.7%, whereas in the “greater than 0.49” group, it was 14%. 4. Discussion The incidence of PPFs of primary hip implants varies from 0.1 to 6.4%, [4,5,11,12], with for Berry et al. [13] a greater incidence of PPFs in the group of patients treated with cementless implants (5.4% in 3121) versus cemented implants (0.3% in 20,589). However, these rates are indicated for populations with highly diverse ages and co-morbidities [14], varied indications [2] and approaches [2], or different implants [1,2,15] (cemented or cementless implants, straight or anatomic stems, THA and different hemiarthroplasties). The present series confirms a higher rate of PPFs with an anatomic cementless stem (15/139; 10.8%). One of the important limitations of this study is the number of patients lost to follow-up (15%) and the number that died (32%). However, our study provides a mean follow-up of 5 years and focuses on patients older than 75 years, with a mean corresponding to the median of 85 years (range, 75–101 years). This explains the high rate of deceased patients. None of the deaths was directly related to a PPF. Among the cases of prosthesis instability not identified in this series, none presented a PPF. Other limitations were related to the retrospective design of the study: • the absence of an analysis of femoral stem filling (difficult to measure on standard X-rays and more reliable with CT); • the absence of quantitative data on the patient’s osteopenia, which requires bone density assessment; the bone weakness indices as related to osteoporosis were only approached by seeking risk factors when investigating the patients’ history (with the patients themselves and their family physicians) and measurement of the radiographic morphological index; • finally, although the analysis was based on standard radiographs, none of the indices measured suffered from lost data (all of the postoperative X-rays could be used) and this study showed good reproducibility of the indices studied. The 10.8% PPF rate of this series is high. This could be related to a higher mean age than in other series [4,6,16]. All studies agree in showing the important role played by osteoporosis, notably the secondary risk factors in the risk of PPF occurrence, but the present study showed that age was not a risk factor of PPF with the numbers of patients available for study. The CBR remains the most reliable morphological index used in this study, which was measureable on standard X-rays. As for the analysis of bone weakness, it cannot be a substitute for bone density examination or a CT scan. However, it remains adapted to the evaluation of bone weakness in an emergency situation. For Franklin et al. [8], who reported a 3.5% PPF rate, the CFI is one of the pivotal indices. For Yeung et al. [10], the CBR is the best indicator of proximal osteoporosis of the femur for a value greater than 0.49, as in our observations. The inter- and intraobserver reproducibility shows its relevance. However, its preoperative analysis on the fractured hip is difficult and, therefore, the contralateral hip must be used as reference. This analysis was not done in this study.
± ± ± ± ±
0.08 0.11 0.11 0.41 4.95
Fracture at follow-up (n = 15) 0.53 0.55 2.93 2.27 138.07
± ± ± ± ±
0.09 0.16 0.69 0.45 3.83
P-value 0.0497 0.4588 0.2974 0.3867 0.0952
The number of patients who presented a PPF (15 patients) remains limited. Early fractures varying between 1 and 5.4% [13,17,18] have been described as related to the introduction of cementless stems and intraoperative preparation seeking maximum filling. In our series, this rate was 3.6%. The lack of experience of the younger surgeons involved in surgery and the intraoperative search for maximum femoral filling seems determinant to us as well as to other authors [1,12]. Male gender seems to play a protective role. The incidence of late PPF is variable but higher (up to 6.4%) than early PPFs [4,8,13,18]. The 7.2% rate of late PPFs found herein is much higher. Contrary to the current study (Fig. 3), for the majority of authors, female gender is a risk factor of later PPFs [8,18]. The factors inherent to the advanced age of this group of patients exclusively older than 78 years (higher than in the early PPF group) and poor bone quality (CBR > 0.49; mean = 0.602 ± 0.03) are more striking. The type of stem probably influenced our high PPF level. In 15,162 THAs, Migaud et al. [1] reported a 2.9% PPF rate with straight stems versus 4.6% with anatomic stems. The variety of cementless stems (geometries, ancillary instrumentation, more or less aggressive rasps, partial or total coatings, etc.) requires extreme caution in the interpretation and comparison of PPF rates. Most often, osteoporosis and its influence are not quantified. Controversy between cemented and cementless arthroplasties persists in favor of a lower PPF rate when using cemented stems [19–21], notably in hemiarthroplasties in patients older than 70 years [22]. Berend et al. [12] consider cementless stems a risk factor for PPF and blame the stem design and the type of instrumentation used. It should be noted, however, that the implants used in most series are Thompson and Austin-Moore stems [3]. As for late PPFs, the risk of late PPF seems identical whether the implants used are cemented or cementless [23]. In a series of 168 patients older than 65 years of age operated for fracture with cementless hemiarthroplasty, Bezwada et al. [24] found no late PPF at a mean follow-up of 3.5 years. At a mean follow-up of 5 years, Keisu et al. [25] (2/86 PPFs) and McAuley et al. [26] (0/152 PPFs) showed good reliability with cementless stems in THAs in patients older than 80 years.
Fig. 3. Kaplan-Meier survival curve relative to PPF (in months) and the log rank test: ), male subject ( ). female subject (
Please cite this article in press as: Kouyoumdjian P, et al. Periprosthetic fracture in the elderly with anatomic modular cementless hemiarthroplasty. Orthop Traumatol Surg Res (2016), http://dx.doi.org/10.1016/j.otsr.2016.05.013
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5. Conclusion The PPF rate reported in our series remains high. With reservations as to the absolute number of PPFs, the CBR appears to be a predictive factor of PPF. With regard to the results presented, in elderly patients we recommend measuring the CBR. In a patient presenting a risk of bone weakness related to the factors of osteoporosis analyzed, associated with a CBR > 0.49, we avoid using cementless stems. Disclosure of interest The authors declare that they have no competing interest. References [1] Migaud H, Pinoit Y, Herent S, et al. Méta-analyse : les prothèses de hanche non cimentées : effet de surface physique et biologique. In: Puget J, editor. Prothèse totale de hanche : monographie de la SOFCOT. Paris: Elsevier; 2005. p. 22–35. [2] Ehlinger M, Delaunay C, Karoubi M, et al. Revision of primary total hip arthroplasty for peri-prosthetic fracture: a prospective epidemiological study of 249 consecutive cases in France. Orthop Traumatol Surg Res 2014;100:657–62. [3] Berend ME, Smith A, Meding JB, Ritter MA, Lynch T, Davis K. Long-term outcome and risk factors of proximal femoral fracture in uncemented and cemented total hip arthroplasty in 2551 hips. J Arthroplasty 2006;21:53–9. [4] Lindahl H. Epidemiology of periprosthetic femur fracture around a total hip arthroplasty. Injury 2007;38:651–4. [5] Malchau H, Herberts P, Eisler T, Garellick G, Soderman P. The Swedish Total Hip Replacement Register. J Bone Joint Surg Am 2002;84(Suppl. 2):2–20. [6] Laffargue P, Soenen M, Pinoit Y, Migaud H. Periprosthetic fractures around total hip and knee arthroplasty. Mortality, morbidity and prognostic factors of periprosthetic femoral fractures following hip arthroplasty: multicentric prospective assessment of 115 cases. Rev Chir Orthop 2006;92(5 Suppl), 2S64–9. [7] Lindahl H, Malchau H, Herberts P, Garellick G. Periprosthetic femoral fractures classification and demographics of 1049 periprosthetic femoral fractures from the Swedish National Hip Arthroplasty Register. J Arthroplasty 2005;20:857–65. [8] Franklin J, Malchau H. Risk factors for periprosthetic femoral fracture. Injury 2007;38:655–60. [9] Begue T, Adam P, Fessy MH, et al. Periprosthetic fractures around total hip and knee arthroplasty. Introduction and study objectives. Rev Chir Orthop 2006;92(5 Suppl), 2S34–6.
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[10] Yeung Y, Chiu KY, Yau WP, Tang WM, Cheung WY, Ng TP. Assessment of the proximal femoral morphology using plain radiograph-can it predict the bone quality? J Arthroplasty 2006;21:508–13. [11] Kavanagh BF. Femoral fractures associated with total hip arthroplasty. Orthop Clin North Am 1992;23:249–57. [12] Berend KR, Lombardi Jr AV. Intraoperative femur fracture is associated with stem and instrument design in primary total hip arthroplasty. Clin Orthop Relat Res 2010;468:2377–81. [13] Berry DJ. Epidemiology: hip and knee. Orthop Clin North Am 1999;30:183–90. [14] Singh JA, Jensen MR, Lewallen DG. Patient factors predict periprosthetic fractures after revision total hip arthroplasty. J Arthroplasty 2012;27:1507–12. [15] Thien TM, Chatziagorou G, Garellick G, et al. Periprosthetic femoral fracture within two years after total hip replacement: analysis of 437,629 operations in the Nordic arthroplasty register association database. J Bone Joint Surg Am 2014;96:e167. [16] 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;91:128–33. [17] Davidson D, Pike J, Garbuz D, Duncan CP, Masri BA. Intraoperative periprosthetic fractures during total hip arthroplasty. Evaluation and management. J Bone Joint Surg Am 2008;90:2000–12. [18] Schwartz Jr JT, Mayer JG, Engh CA. Femoral fracture during non-cemented total hip arthroplasty. J Bone Joint Surg Am 1989;71:1135–42. [19] Foster AP, Thompson NW, Wong J, Charlwood AP. Periprosthetic femoral fractures – a comparison between cemented and uncemented hemiarthroplasties. Injury 2005;36:424–9. [20] Singh GK, Deshmukh RG. Uncemented Austin-Moore and cemented Thompson unipolar hemiarthroplasty for displaced fracture neck of femur – comparison of complications and patient satisfaction. Injury 2006;37:169–74. [21] Khan RJ, MacDowell A, Crossman P, et al. Cemented or uncemented hemiarthroplasty for displaced intracapsular femoral neck fractures. Int Orthop 2002;26:229–32. [22] Wachtl SW, Jakob RP, Gautier E. Ten-year patient and prosthesis survival after unipolar hip hemiarthroplasty in female patients over 70 years old. J Arthroplasty 2003;18:587–91. [23] Sarvilinna R, Huhtala HS, Sovelius RT, Halonen PJ, Nevalainen JK, Pajamaki KJ. Factors predisposing to periprosthetic fracture after hip arthroplasty: a case (n = 31)-control study. Acta Orthop Scand 2004;75:16–20. [24] Bezwada HP, Shah AR, Harding SH, Baker J, Johanson NA, Mont MA. Cementless bipolar hemiarthroplasty for displaced femoral neck fractures in the elderly. J Arthroplasty 2004;19:73–7. [25] Keisu KS, Orozco F, Sharkey PF, Hozack WJ, Rothman RH, McGuigan FX. Primary cementless total hip arthroplasty in octogenarians. Two to eleven-year followup. J Bone Joint Surg Am 2001;83:359–63. [26] McAuley JP, Moore KD, Culpepper WJ 2nd, Engh CA. Total hip arthroplasty with porous-coated prostheses fixed without cement in patients who are sixty-five years of age or older. J Bone Joint Surg Am 1998;80:1648–55.
Please cite this article in press as: Kouyoumdjian P, et al. Periprosthetic fracture in the elderly with anatomic modular cementless hemiarthroplasty. Orthop Traumatol Surg Res (2016), http://dx.doi.org/10.1016/j.otsr.2016.05.013
ARTICLE IN PRESS Orthopaedics & Traumatology: Surgery & Research xxx (2016) xxx–xxx
Available online at
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Original article
Periprosthetic fracture in the elderly with anatomic modular cementless hemiarthroplasty P. Kouyoumdjian a,∗ , A. Dhenin a , A. Dupeyron b , R. Coulomb a , G. Asencio a a b
Service de chirurgie orthopédique et traumatologique, hôpital Carémeau, CHU de Nîmes, place de Pr-R.-Debré, 30000 Nîmes, France Service de médecine physique et réadaptation, CHU de Nîmes, hôpital Carémeau, place de Pr-R.-Debré, 30000 Nîmes, France
a r t i c l e
i n f o
Article history: Received 15 November 2015 Accepted 10 May 2016 Keywords: Periprosthetic fracture Hemiarthroplasty Hip Cementless stem Osteoporosis
a b s t r a c t Background: The use of an anatomic cementless stem in hemiarthroplasties for femoral intracapsular proximal fracture has been debated, notably because of bone weakness and/or morphological defects related to osteoporosis. We therefore conducted a retrospective study in subjects over 75 years of age who had received an anatomic stem partially coated with hydroxyapatite. The objectives were to determine: 1) the incidence of periprosthetic fractures (PPFs) and, 2) the influence of anatomic factors, including the Cortical Bone Ratio (CBR) (the relation between the endosteal and external diameter of the femoral diaphysis 10 cm below the lesser trochanter). Hypothesis: The risk of PPF with an anatomic cementless implant is greater than with cemented stems. Material and methods: We retrospectively analyzed 233 patients followed up for 5 years after their surgery. The stem used was an anatomic stem with a modular neck partially coated with hydroxyapatite. The risk factors examined were age, gender, history of osteoporotic fractures, diverse causes of secondary osteoporosis, and proximal bone stock according to various referenced radiological indices such as the CBR. Results: Twenty patients (15%) were lost to follow-up, 74 had died (32%) but did not undergo revision for PPF, 15 of the 139 survivors at the last follow-up (10.8%) had had a PPF, five (3.6%; four females, one male) were early fractures (≤ 2 months after implantation), ten (7.2%; two females, eight males) were late fractures (> 2 months). Male gender was protective for PPF occurrence (RR = 0.129; 95%CI (0.04–0.39); P = 0.0003), whereas secondary factors of osteoporosis (RR = 2.035; 95%CI (1.11–3.72); P = 0.0211), and CBR > 0.49 (RR = 227.42; 95%CI (1.072–48,226.76); P = 0.0471) were found as risk factors of PPF. Discussion: The PPF rate was greater than that related to cemented stems, requiring that morphological and clinical factors of bone weakness (collected with the patient history and related to osteoporosis) be taken into account. A CBR > 0.49 requires caution on the use of this type of stem. Level of evidence: Level 4. Retrospective study. © 2016 Elsevier Masson SAS. All rights reserved.
1. Introduction The results of hemiarthroplasty in the treatment of femoral neck fractures in the elderly patient are conditioned by the quality of the surgical technique, as well as the type of implant and fixation [1,2]. Berend et al. [3] showed that the rates of periprosthetic fractures (PPFs) after total hip arthroplasty (THA) were greater after implantation of cementless stems (6.4%) versus cemented stems (2.3%). Lindahl et al. [4] reported a rate increasing from 0.3% PPFs for cemented stems to 5.4% for cementless stems.
∗ Corresponding author. Tel.: +33603998081; fax: +33466218057. E-mail address: [email protected] (P. Kouyoumdjian).
Today, PPFs are indeed one of the leading causes of THA complications [2–4]. According to the Swedish Total Hip Replacement Register [5], the annual incidence increases with time and varies between 0.045 and 0.13%. This is a serious and frequent complication whose morbidity varies between 8.7 and 22.9% depending on the series, and mortality is estimated by Laffargue et al. [6] and Lindahl et al. [7] at 9.8%. Other than the modifications of the bone matrix related to osteopenia, the risk factors of PPF that have been identified are age [7] and osteoporosis [8]. However, modifications in the shape of the medullary canal related to aging have not been evaluated in this situation [6–8]. In a group of subjects older than 75 years treated for intracapsular femoral neck fracture with cementless with an anatomic stem partially coated with hydroxyapatite, we conducted a retrospective study aiming to determine 1) the rate of PPFs and 2) the
http://dx.doi.org/10.1016/j.otsr.2016.05.013 1877-0568/© 2016 Elsevier Masson SAS. All rights reserved.
Please cite this article in press as: Kouyoumdjian P, et al. Periprosthetic fracture in the elderly with anatomic modular cementless hemiarthroplasty. Orthop Traumatol Surg Res (2016), http://dx.doi.org/10.1016/j.otsr.2016.05.013
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influence of anatomic factors using the Cortical Bone Ratio (CBR). We hypothesized that the risk of PPF with this type of implant would be greater, notably compared to the studies reported in the literature on cemented stems. 2. Material and methods 2.1. Patients We retrospectively analyzed a continuous, single-center series between January 2002 and December 2004, made up of 287 patients aged 75 years or older who had presented an intracapsular femoral neck fracture at the proximal end of the femur treated with hip hemiarthroplasty via the posterolateral approach. The following were excluded from the study (Fig. 1): bedridden patients, pathological femoral neck fractures, cemented arthroplasties (intraoperative choice given subjective evaluation of bone weakness), and revisions of these arthroplasties for reasons other than PPF (infection, instability, osteosynthesis revision by stem reconstruction or cemented stem); none of these cases had PPF.
This series comprised 233 healthy (Parker score > 6) cases with a mean age of 84.6 years (range, 75–101 years), including 168 females (72.1%) and 65 males (27.8%). The implant used in all cases was an anatomic MBATM stem (Lépine, Genay, France) with the proximal third coated with hydroxyapatite (Fig. 2), including a modular neck with two Morse tapers associated with a stainless steel head and a mobile cup. One hundred thirty-nine patients were followed with a minimum follow-up of 5 years, 74 patients (32%) had died (two in the first 2 months after surgery), and 20 patients (15%) were lost to follow-up. None of the deaths were directly related to the arthroplasty, notably none were related to a PPF. A total of 139 patients (109 females [78.4%] and 30 males [21.6%]), with a mean age at implantation of 84 years (range, 75–100 years), were seen with a minimum follow-up of 5 years (Fig. 1). 2.2. Assessment methods Several criteria were investigated: age, gender, osteoporosisrelated risk factors, and radiological morphological criteria related to possible bone weakness. This study analyzed the following
Fig. 1. Flowchart of the series.
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◦ the Canal Flare Index (CFI), the relationship between the endosteal diameter measured 10 cm below the lesser trochanter and the diameter measured 2 cm above. Measurements were taken using the Osirix v.3.8 32 bitTM software (Geneva, Switzerland). The lower Morse taper of the stem’s modular neck (12 mm) was used as the reference for scaling. 2.3. Statistical analysis
Fig. 2. MBA prosthesis (Lépine, Genay, France). Radiographic indices measured [10]: A: endosteal diameter 2 cm above the lesser trochanter; B: external diameter of the femur at the lesser trochanter; C: endosteal diameter of the femur at the lesser trochanter; D: endosteal diameter 7 cm below the lesser trochanter; E: endosteal diameter 10 cm below the lesser trochanter; F: external diameter of the femur 10 cm below the lesser trochanter. Dorr’s Canal Calcar Ratio (CCR) equal to E/C; Noble’s Canal Flare Index (CFI) equal to A/E; Spotorno’s Morphological Cortical Index (MCI) equal to B/D; Cortical Bone Ratio (CBR) equal to E/F.
risk factors of osteoporosis-related bone weakness: a history of dysthyroidism, hypercorticism, rheumatoid arthritis, ankylosing spondylitis, chronic inflammatory digestive diseases, thyroid or corticoid hormone treatments, chemotherapies, and a history of osteoporotic fractures (distal radius, proximal humerus, spinal cord, proximal contralateral femur). All PPFs were assessed for frequency, time to occurrence, and type (SOFCOT modified Vancouver classification [9]). Early PPFs were considered as occurring intraoperatively and during the 2 months following surgery; beyond this time they were considered late fractures. The radiographic analysis was performed by three independent observers and three times for each of them. The radiological indices for proximal femur bone weakness described in the literature [10] and measured on the postoperative image were (Fig. 2): • the index of diaphyseal cortical bone thinning: the CBR, the relationship between the endosteal and external diameter of the femoral diaphysis 10 cm below the lesser trochanter; • the index of metaphyseal cortical bone thinning: the Morphological Cortical Index (MCI), the relationship between the external diameter of the femur at the lesser trochanter and the endosteal diameter 7 cm below; • proximal femur indices such as: ◦ the relationship between the femoral endosteal diameter 10 cm below and the diameter at the lesser trochanter, or the Canal Calcar Ratio (CCR),
A Cox multivariate model with adjusted logistical regression was used to model the time to PPFs’ occurrence. Implant survival, as related to the occurrence of a PPF and depending on gender, was assessed using the Kaplan-Meier method. Evaluation of the risk of PPF occurrence depending on gender was determined using the Logrank test. The risk of fracture for each additional secondary osteoporosis risk factor was determined using the Cochran-Armitage test for trend. The age for which the risk of fracture was the greatest was assessed using cluster analysis. The results were considered significant if P < 0.05. Inter- and intraclass concordance of the radiographic indices were evaluated using the Lin concordance correlation coefficient. 3. Results We found very good reproducibility of the measurements for the indices measured. The CBR was the most reproducible index in this study (Table 1). At the last follow-up (78 months; range, 62–108 months), 15 PPFs (nine males and six females; 10.8% of the patients) had occurred. The mean age at injury was 84.5 years (range, 78–100 years). There were four Ag fractures and 11 B2 fractures. Early PPFs (0–32 days) occurred in five patients (four females and one male), with a mean age of 80.8 years (range, 78–86 years) at the time of injury, with one intraoperative PPF and the others secondary to a fall. Ten patients (eight males and two females), a mean 86.3 years old (range, 83–90 years) at the time the index fracture occurred, presented a late PPF with a mean time to injury of 17 months (range, 8–60 months). Age did not appear to be a risk factor. Thirty-two patients (23%) presented at least one of the above-mentioned risk factors for secondary osteoporosis. The presence of at least one risk factor reported in the patient’s history and classified at the same level was noted as a significant predictive factor of both early and late PPF (RR = 1.74; 95%CI (0.983–3.08); P = 0.0211). The accumulation of risk factors for osteoporosis considerably increased the risk of PPF (RR = 2.035; 95%CI (1.11–3.72); P = 0.088): 8.3% for one, 18% for two, and 100% for three risk factors. Male gender was protective against early PPF (RR = 0.129; 95%CI (0.04–0.39); P = 0.0003). On the other hand, the analysis of survival curves according to gender showed a greater risk of late PPF in males (P = 0.0001) (Fig. 2). Of the radiological indices measured, only the CBR was found to be determinant (Table 2). In reference to the threshold value reported by Yeung et al. [10], we noted an increased risk of PPF for a CBR > 0.49 (RR = 227.42; 95%CI (1.072–48226.76)). In the “less
Table 1 Lin’s inter- and intraobserver concordance correlation coefficient (CCC) for the different radiological variables calculated. Interobserver CCC Inter-CCC Canal Calcar Ratio Canal Flare Index Morphological Cortical Index Cortical Bone Ratio
0.975 0.986 0.978 0.999
Intraobserver CCC Range 0.974–0.9776 0.984–0.988 0.976–0.99 0.998–0.999
Intra-CCC 0.981 0.984 0.980 0.999
Range 0.973–0.998 0.981–0.997 0.941–0.997 0.990–0.999
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Table 2 Mean and standard deviation of different radiological variables. Variable
All subjects (n = 139)
Cortical Bone Ratio Canal Calcar Ratio Canal Flare index Morphological Cortical Index Neck-head angle
0.53 0.52 3.11 2.37 135.88
± ± ± ± ±
0.08 (0.32–0.79) 0.12 (0.34–0.88) 0.68 (1.49–4.73) 0.42 (1.36–3.53) 4.89 (122–148)
No fracture at follow-up (n = 124) 0.57 0.52 3.13 2.38 135.61
than or equal to 0.49” group, the PPF rate was 5.7%, whereas in the “greater than 0.49” group, it was 14%. 4. Discussion The incidence of PPFs of primary hip implants varies from 0.1 to 6.4%, [4,5,11,12], with for Berry et al. [13] a greater incidence of PPFs in the group of patients treated with cementless implants (5.4% in 3121) versus cemented implants (0.3% in 20,589). However, these rates are indicated for populations with highly diverse ages and co-morbidities [14], varied indications [2] and approaches [2], or different implants [1,2,15] (cemented or cementless implants, straight or anatomic stems, THA and different hemiarthroplasties). The present series confirms a higher rate of PPFs with an anatomic cementless stem (15/139; 10.8%). One of the important limitations of this study is the number of patients lost to follow-up (15%) and the number that died (32%). However, our study provides a mean follow-up of 5 years and focuses on patients older than 75 years, with a mean corresponding to the median of 85 years (range, 75–101 years). This explains the high rate of deceased patients. None of the deaths was directly related to a PPF. Among the cases of prosthesis instability not identified in this series, none presented a PPF. Other limitations were related to the retrospective design of the study: • the absence of an analysis of femoral stem filling (difficult to measure on standard X-rays and more reliable with CT); • the absence of quantitative data on the patient’s osteopenia, which requires bone density assessment; the bone weakness indices as related to osteoporosis were only approached by seeking risk factors when investigating the patients’ history (with the patients themselves and their family physicians) and measurement of the radiographic morphological index; • finally, although the analysis was based on standard radiographs, none of the indices measured suffered from lost data (all of the postoperative X-rays could be used) and this study showed good reproducibility of the indices studied. The 10.8% PPF rate of this series is high. This could be related to a higher mean age than in other series [4,6,16]. All studies agree in showing the important role played by osteoporosis, notably the secondary risk factors in the risk of PPF occurrence, but the present study showed that age was not a risk factor of PPF with the numbers of patients available for study. The CBR remains the most reliable morphological index used in this study, which was measureable on standard X-rays. As for the analysis of bone weakness, it cannot be a substitute for bone density examination or a CT scan. However, it remains adapted to the evaluation of bone weakness in an emergency situation. For Franklin et al. [8], who reported a 3.5% PPF rate, the CFI is one of the pivotal indices. For Yeung et al. [10], the CBR is the best indicator of proximal osteoporosis of the femur for a value greater than 0.49, as in our observations. The inter- and intraobserver reproducibility shows its relevance. However, its preoperative analysis on the fractured hip is difficult and, therefore, the contralateral hip must be used as reference. This analysis was not done in this study.
± ± ± ± ±
0.08 0.11 0.11 0.41 4.95
Fracture at follow-up (n = 15) 0.53 0.55 2.93 2.27 138.07
± ± ± ± ±
0.09 0.16 0.69 0.45 3.83
P-value 0.0497 0.4588 0.2974 0.3867 0.0952
The number of patients who presented a PPF (15 patients) remains limited. Early fractures varying between 1 and 5.4% [13,17,18] have been described as related to the introduction of cementless stems and intraoperative preparation seeking maximum filling. In our series, this rate was 3.6%. The lack of experience of the younger surgeons involved in surgery and the intraoperative search for maximum femoral filling seems determinant to us as well as to other authors [1,12]. Male gender seems to play a protective role. The incidence of late PPF is variable but higher (up to 6.4%) than early PPFs [4,8,13,18]. The 7.2% rate of late PPFs found herein is much higher. Contrary to the current study (Fig. 3), for the majority of authors, female gender is a risk factor of later PPFs [8,18]. The factors inherent to the advanced age of this group of patients exclusively older than 78 years (higher than in the early PPF group) and poor bone quality (CBR > 0.49; mean = 0.602 ± 0.03) are more striking. The type of stem probably influenced our high PPF level. In 15,162 THAs, Migaud et al. [1] reported a 2.9% PPF rate with straight stems versus 4.6% with anatomic stems. The variety of cementless stems (geometries, ancillary instrumentation, more or less aggressive rasps, partial or total coatings, etc.) requires extreme caution in the interpretation and comparison of PPF rates. Most often, osteoporosis and its influence are not quantified. Controversy between cemented and cementless arthroplasties persists in favor of a lower PPF rate when using cemented stems [19–21], notably in hemiarthroplasties in patients older than 70 years [22]. Berend et al. [12] consider cementless stems a risk factor for PPF and blame the stem design and the type of instrumentation used. It should be noted, however, that the implants used in most series are Thompson and Austin-Moore stems [3]. As for late PPFs, the risk of late PPF seems identical whether the implants used are cemented or cementless [23]. In a series of 168 patients older than 65 years of age operated for fracture with cementless hemiarthroplasty, Bezwada et al. [24] found no late PPF at a mean follow-up of 3.5 years. At a mean follow-up of 5 years, Keisu et al. [25] (2/86 PPFs) and McAuley et al. [26] (0/152 PPFs) showed good reliability with cementless stems in THAs in patients older than 80 years.
Fig. 3. Kaplan-Meier survival curve relative to PPF (in months) and the log rank test: ), male subject ( ). female subject (
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5. Conclusion The PPF rate reported in our series remains high. With reservations as to the absolute number of PPFs, the CBR appears to be a predictive factor of PPF. With regard to the results presented, in elderly patients we recommend measuring the CBR. In a patient presenting a risk of bone weakness related to the factors of osteoporosis analyzed, associated with a CBR > 0.49, we avoid using cementless stems. Disclosure of interest The authors declare that they have no competing interest. References [1] Migaud H, Pinoit Y, Herent S, et al. Méta-analyse : les prothèses de hanche non cimentées : effet de surface physique et biologique. In: Puget J, editor. Prothèse totale de hanche : monographie de la SOFCOT. Paris: Elsevier; 2005. p. 22–35. [2] Ehlinger M, Delaunay C, Karoubi M, et al. Revision of primary total hip arthroplasty for peri-prosthetic fracture: a prospective epidemiological study of 249 consecutive cases in France. Orthop Traumatol Surg Res 2014;100:657–62. [3] Berend ME, Smith A, Meding JB, Ritter MA, Lynch T, Davis K. Long-term outcome and risk factors of proximal femoral fracture in uncemented and cemented total hip arthroplasty in 2551 hips. J Arthroplasty 2006;21:53–9. [4] Lindahl H. Epidemiology of periprosthetic femur fracture around a total hip arthroplasty. Injury 2007;38:651–4. [5] Malchau H, Herberts P, Eisler T, Garellick G, Soderman P. The Swedish Total Hip Replacement Register. J Bone Joint Surg Am 2002;84(Suppl. 2):2–20. [6] Laffargue P, Soenen M, Pinoit Y, Migaud H. Periprosthetic fractures around total hip and knee arthroplasty. Mortality, morbidity and prognostic factors of periprosthetic femoral fractures following hip arthroplasty: multicentric prospective assessment of 115 cases. Rev Chir Orthop 2006;92(5 Suppl), 2S64–9. [7] Lindahl H, Malchau H, Herberts P, Garellick G. Periprosthetic femoral fractures classification and demographics of 1049 periprosthetic femoral fractures from the Swedish National Hip Arthroplasty Register. J Arthroplasty 2005;20:857–65. [8] Franklin J, Malchau H. Risk factors for periprosthetic femoral fracture. Injury 2007;38:655–60. [9] Begue T, Adam P, Fessy MH, et al. Periprosthetic fractures around total hip and knee arthroplasty. Introduction and study objectives. Rev Chir Orthop 2006;92(5 Suppl), 2S34–6.
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Please cite this article in press as: Kouyoumdjian P, et al. Periprosthetic fracture in the elderly with anatomic modular cementless hemiarthroplasty. Orthop Traumatol Surg Res (2016), http://dx.doi.org/10.1016/j.otsr.2016.05.013