Revision Hip Education and Context
The following articles provide background and context for understanding the complexities of revision THA. The classification of femoral defects from bone loss, and the classification of periprosthetic fractures are described by the first two studies. The third study describes Extended Trochanteric Osteotomy (ETO), a technique for surgically approaching the distal portion of the femur sometimes employed in placing long revision stems. The last two articles debate the need for modularity in the proximal body of a revision stem.
The Journal of Bone and Joint Surgery (American) 85:1-6 (2003). "Classification and an Algorithmic Approach to the Reconstruction of Femoral Deficiency in Revision Total Hip Arthroplasty," Craig J. Della Valle, MD and Wayne G. Paprosky, MD.
As the number of patients who have undergone total hip arthroplasty rises, the number of patients requiring revision surgery for a failed total hip arthroplasty increases as well. It is estimated that 183,000 total hip replacements were performed in the United States in 2000 and that 31,000 (17%) of these were revision procedures. Femoral reconstruction at the time of revision total hip arthroplasty can be challenging both from a technical perspective and in terms of preoperative planning. With multiple reconstructive options available, it is helpful to have a classification system available to guide the surgeon in selecting the appropriate method of reconstruction. A system for the classification of femoral deficiency that was developed by the senior author (W.G.P.) and an algorithmic approach to femoral reconstruction are presented in the current report.
The Journal of Arthoplasty, Volume 15, Number 1 (2000). "The Reliability and Validity of the Vancouver Classification of Femoral Fractures after Hip Replacement," Owen H. Brady, MB, MCh (Orth), FRCSI (Orth); Donald S. Garbuz, MD, MHSc, FRCSC; Bassam A. Masri, MD, FRCSC; Clive P. Duncan, MB, MSC, FRCSC.
This study assessed the reliability and validity of a new classification system for fractures of the femur after hip arthroplasty. Forty radiographs were evaluated by 6 observers, 3 experts and 3 nonexperts. Each observer read the radiographs on 2 separate occasions and classified each case as to its type (A, B, C) and subtype (B1, B2, B3). Reliability was assessed by looking at the intraobserver and interobserver agreement using the κ statistic. Validity was assessed within the B group by looking at the agreement between the radiographic classification and the intraoperative findings. Our findings suggest that this classification system is reliable and valid. Intraobserver agreement was consistent across observers, ranging from 0.73 to 0.83. There was a negligible difference between experts and nonexperts. Interobserver agreement was 0.61 for the first reading and 0.64 for the second reading by κ analysis, indicating substantial agreement between observers. Validity analysis revealed an observed agreement κ value of 0.78, indicating substantial agreement. This study has shown that this classification is reliable and valid.
The Journal of Arthroplasty, Volume 18, Issue 3, Supplement, Pages 91-93 (April 2003). "Controlled Femoral Fracture: Easy In," Wayne G. Paprosky, MD; Scott M. Sporer, MD.
Revision femoral surgery is a demanding procedure with the potential for severe intraoperative complications, including bone loss and femoral fracture. The extended trochanteric osteotomy is a reproducible and safe technique to remove the femoral components for infection, loosening, component failure, malposition, and dislocation. From 1992 to 1996, 142 consecutive hip revisions were performed with the use of an extended proximal femoral osteotomy. This technique allowed component extraction without fracture in all patients and subsequently allowed for neutral reaming of the femoral canal with placement of the revision stems in proper alignment. There were 2 nonunions of the osteotomized fragments at an average postoperative follow-up period of 2.6 years. Additional complications included 4 fractures of the osteotomized fragment and one malunion. We have found that use of the osteotomy is an efficient, safe and reliable technique in revision hip arthroplasty.
The Journal of Arthroplasty, Volume 18, Issue 3, Supplement, Pages 98-100 (April 2003). "Orthopaedic Crossfire®—Stem Modularity is Unnecessary in Revision Total Hip Arthroplasty: In the Affirmative," Robert L. Barrack, MD.
Numerous options are available for femoral stem fixation in revision total hip arthroplasty, including cemented stems, proximally-coated cementless stems, extensively coated cementless stems, impaction grafting cemented stems, and modular cementless stems. In terms of versatility, ease of insertion, use with an extended trochanteric osteotomy, and clinical results, extensively coated cementless stems remain the gold standard. Modular cementless stems have not matched the clinical results of extensively coated cementless stems. In addition, modular stems introduce increased complexity, cost, and potential complications and are therefore, rarely, if ever, necessary in revision total hip arthroplasty.
The Journal of Arthroplasty, Volume 18, Issue 3, Supplement, Pages 101-103 (April 2003). "Orthopaedic Crossfire®—Stem Modularity is Unnecessary in Revision Total Hip Arthroplasty: In Opposition," Hugh U. Cameron, MB, ChB, FRCSC.
If distal fixation is a goal in revision hip surgery, then modularity may not be necessary. If, however, proximal fixation is desired, both proximal and distal fit and fill are necessary to achieve initial stability. This can only be done in the revision situation by using a modular stem. Long-term follow up of 320 revision cases treated using a proximally modular proximal ingrowth stem shows a re-revision rate for late aseptic loosening of 0.93% at a mean time of 7 years, indicating that such a stem is a reasonable option.
Wagner SL Revision Hip Articles
These articles concern experience with the original Wagner SL revision stem, the one-piece stem that originated the fluted, tapered, blasted, cylindrical distal geometry that subsequent modular revision implants including the Lima Revision stem have incorporated.
The Journal of Bone and Joint Surgery (American) 83:1023-1031 (2001). "Femoral Revision with the Wagner SL Revision Stem: Evaluation of One Hundred and Twenty-nine Revisions Followed for a Mean of 4.8 Years," Paul Böhm, MD and Oliver Bischel, MD.
Background: It is difficult to achieve a successful revision total hip replacement when a patient has severe proximal femoral bone loss. The Wagner SL revision stem has some theoretical advantages, but the durability of this prosthesis is not known.
Methods: We reviewed the results of 129 revisions of the femoral component with a Wagner SL revision stem in 123 patients. The indication for revision was aseptic loosening in ninety-seven hips, periprosthetic fracture in thirteen (one of which also had an infection), and septic loosening in sixteen. In the three remaining hips, a Wagner revision stem was inserted during a second-stage reimplantation after the performance of a Girdlestone resection arthroplasty to treat chronic deep infection. The prerevision defects were classified with the system described by Pak et al. as well as with our system. A functional evaluation of the patients and a survival analysis of the revision stems were performed.
Results: The mean duration of follow-up was 4.8 years (range, two months to 11.1 years). Six revision stems required repeat revision. With removal of the stem for any cause or the worst case (removal of the stem for any cause and/or lost to follow-up) as the end point, cumulative survival at 11.1 years was 93.9% and 92.8%, respectively. The mean Merle d'Aubigné score improved from 7.7 points preoperatively to 14.8 points at the latest follow-up examination. The most recent radiographs showed good or excellent restoration of the proximal part of the femur in 113 hips (88%).
Conclusions: Because of the encouraging results of implantation of this femoral component with distal fixation, we will continue to use it in the majority of femoral revisions. However, the need for regular follow-up remains, since the rate of complications such as osteolysis of the femur, aseptic loosening, periprosthetic fracture, and late infection may increase in the future.
The Journal of Arthroplasty Volume 18, Issue 4, Pages 446-452 (June 2003). "Distal Fixation with Wagner Revision Stem in Treating Vancouver Type B2 Periprosthetic Femur Fractures in Geriatric Patients," P.S Ko, J.J Lam, M.K Tio, O.B Lee, F.K Ip.
Periprosthetic fractures around hip prostheses are difficult problems. We reviewed the results of treatment with Wagner revision stems in geriatric patients (≥ 65 years old) with Vancouver type B2 periprosthetic fractures. Over a 5-year period, 14 patients with Vancouver's type B2 periprosthetic fractures in the proximal femur were revised. The mean follow-up for these patients was 58.5 months (range, 36 to 64 months). The average age was 74.5 years (67 to 83 years). Twelve patients were available for assessment; all 12 reconstructions showed a stable prosthesis and solid fracture union. Seven patients had excellent outcome, 3 had a good outcome, and 2 had a poor outcome. Our series shows that the Wagner revision stem is a satisfactory prosthesis in revision of Vancouver type B2 periprosthetic fractures in geriatric patients.
The Journal of Arthroplasty Volume 22, Issue 4, Pages 515-524 (June 2007). "Radiographic Bone Regeneration and Clinical Outcome With the Wagner SL Revision Stem: A 5-Year to 12-Year Follow-Up Study," José Gutiérrez del Alamo, MD; Eduardo Garcia-Cimbrelo, MD; Vicente Castellanos, MD; Enrique Gil-Garay, MD.
We used 79 Wagner SL stems (Sulzer Orthopedics, Baar, Switzerland) in femoral revisions with a minimum 5-year follow-up. There were 11 dislocations. A limb length discrepancy and limp were frequent. One loosened stem was rerevised. The cumulative probability of not having a stem revision for any reason was 92.3% in the best case scenario. Stem subsidence was associated with poor femoral canal filling. Definite proximal new bone regeneration (50 hips) was associated with an absence of major bone defects (P = .01). Lateral and medial femoral cortex and the outside femoral diameter had increased at the end of follow-up (P < .001). Wagner SL femoral revision stems can solve difficult cases with major proximal bone defects or periprosthetic fractures. Radiographic bone fixation and bone regeneration were frequent. Dislocations and stem subsidence were also frequent.
Lima Modular Revision Hip Articles
These articles are studies in which the Lima Revision stem was used to treat study patients. The last two studies use a variety of modular revision stems, of which Lima Revision was just one. Given the wide-ranging complexity of revision THA cases and relative novelty of modular revision stems such as the Lima Revision, the studies are more focused on treatment techniques than on the merits of specific devices.
The Journal of Arthroplasty Volume 22, Issue 7, Pages 993-999 (October 2007). "Revision Total Hip Arthroplasty Using a Fluted and Tapered Modular Distal Fixation Stem With and Without Extended Trochanteric Osteotomy," Youn-Soo Park, MD; Young-Wan Moon, MD; Seung-Jae Lim, MD.
We reviewed 62 revision total hip arthroplasties performed using a fluted and tapered modular distal fixation stem after a mean follow-up of 4.2 years. An extended trochanteric osteotomy (ETO) was used in 32 of the 62 hips (52%), whereas no osteotomy was used in the remaining 30 hips. The mean postoperative Harris hip score among the patients was 87.3 points. The mean stem subsidence was 1.1 mm. With the exception of one reoperation for a deep infection, no femoral revision was performed because of mechanical failure. Complications included intraoperative diaphyseal split fractures (6%), cortical perforations (6%), and dislocations (5%). Postoperative Harris hip scores, femoral component stability, and overall complication rates did not differ between the group treated with an ETO and that treated without it. However, the rates of cortical perforation and marked stem subsidence (>5 mm) were significantly higher in the group treated without an ETO than those in the group treated with an ETO, but these were not significantly different when stratified by femoral bone defect. The potential advantages of this implant design could be highlighted in a clinical setting when inserted using an ETO.
Sci.Med. J. ESCME Vol. 17, No.3 July 2005. "Cementless Revision Total Hip Replacement Using Modular Stems," Ahmed Emad EL Din Rady, Ahmed Galal Eldin Ibrahim, Amr Abdel Kader Hammad Abou El Ela.
This study evaluates the early results of the use of a modular cementless hip prosthesis for management of difficult revision hip surgeries. Thirty cases (23 male and 7 female) with a mean age of 51.4 years old (range 31 to 78 years old), were followed up for a mean period of 18.7 months (range 7 to 27 months). The reason for revision was: aseptic loosening in twenty six cases (86.6%), and peri-prosthetic femoral fractures in four cases (13.4%). The American Academy of Orthopedic Surgeons (AAOS) classification 1993 was used to classify the femoral deficiency in 26 cases. The Vancouver Classification of Duncan et al 1997 was used to classify the peri-prosthetic femoral fracture, which has been considered as a special type of bone deficiency in 4 cases. The Trans-Femoral approach or the Fenestration technique was used in most of these revision surgeries for safe and complete removal of bone cement. Intraluminal and circumferential femoral bone defects were managed using autograft, and synthetic bone substitutes. The Harris Hip Score System (HHS) was used for clinical evaluation of our cases. This HHS significantly improved from 23.99 points (range 0 to 38.07) before the revision to 87.5 points (range 62.12 to100) at the final follow-up. Radiologically all cases showed spontaneous refill with remodeling of the proximal femur which ranged from 7m to 17m with a mean value about 9.2m. The Trans-Femoral osteotomy united within 7m to 12m with a mean value about 11.5m while Femoral Fenestrations were healed at a time ranged from 4m to 7m with a mean value about 5.7m. The observed complications were in 5 cases (16.6%) These complications were; dislocation in two cases (6.6%), infection in two cases (6.6%) and subsidence in only one case (3.3%).
The Journal of Arthoplasty, Volume 24, Issue 8, Pages 1270-1276 (December 2009). "Management of Periprosthetic Femur Fractures Treated With Distal Fixation Using a Modular Femoral Stem Using an Anterolateral Approach," Myung-Sik Park, MD; Yung-Jin Lim, MD; Woo-Chul Chung, MD; Dong-Hun Ham, MD; Sang-Hong Lee, MD.
The authors retrospectively analyzed 27 hips with periprosthetic femoral fractures (types B2 and B3) treated with distal fixation using a modular, fluted, femoral stem. The average follow-up was 4.8 years. Most fractures (25 hips) were united (92.6%), and mean Harris Hip Score at follow-up was 84.7. Subsidence was noted in 2 patients within 6 months postoperatively, but despite the subsidence, one achieved union. One patient developed peroneal nerve palsy. Two hips were defined as failure: one nonunion associated with infection, and the other one had 10 mm more subsidence. No dislocation occurred in any of the patients. This technique has proven to be reliable in the treatment of difficult fractures in the acute stage, although concerns regarding the subsidence remain when using this femoral stem.
The Journal of Arthroplasty, Volume 24, Issue 8, Pages 1241-1248 (December 2009). "The Use of Allograft Prosthesis Composite for Extensive Proximal Femoral Bone Deficiencies: A 2- to 9.8-Year Follow-Up Study," Soo H. Lee, MD; Young J. Ahn, MD; Sae J. Chung, MD; Byeong K. Kim, MD; Ji H. Hwang, MD.
We report here results for 15 hips that we repaired using allograft prosthesis composite (APC) and monitored for a mean of 4.2 years. Two hips underwent repeat revisions with new APCs after a mean of 83.7 months. The average Harris Hip Score improved from 21.8 before revision surgery to 83.2 afterward, and 12 stems showed good stability. Of the 15 hips repaired with APC, 13 had good junctional union. One of the 2 remaining hips showed nonunion, which was repaired with an onlay graft 3.3 years later, and the other hip showed both infection and nonunion. There was 1 dislocation, and 2 hips had complications related to the greater trochanter. Our findings demonstrate that the use of APC produces satisfactory results.
Link MP Prosthesis Articles
Link-MP is the device on the market that bears the most similarity to the Lima Revision Stem. These studies are useful in understanding how this very similar device to Lima Revision has performed over time, and in providing context for uses of the Lima Revision Stem.
The Journal of Arthroplasty, Volume 25, Issue 6, Pages 932-938 (September 2010). "A Distal Fluted, Proximal Modular Femoral Prosthesis in Revision Hip Arthroplasty," Myung-Sik Park, MD; Ju-Hong Lee, MD; Jong-Hyuk Park, MD; Dong-Hun Ham, MD; Yang-Keun Rhee, MD.
Most reports on the use of modular femoral stems during revision surgery have involved short follow-up periods. The authors evaluated the clinical and radiographic performance of 59 patients fitted with a distal fix modular stem. The average follow-up period was 8.2 years. Average Harris hip score was improved from 47 to 87.6. Of 19 patients with trochanteric osteotomy, 4 had a displaced greater trochanter. Re-revision was performed in 5 patients, and 3 of these were for subsidence (of these 3, subsidence was associated with dissociation of the coupling part in 1 and with osteotomy nonunion in other 2 [proximal component only]). Modular distally fixed femoral stems were found to offer intraoperative flexibility, but to suffer from subsidence and intraoperative greater trochanter and metaphyseal femoral fractures.
The Journal of Arthoplasty, Volume 19, Issue 4, Supplement 1, Pages 115-119 (June 2004). "Revision Total Hip Arthroplasty with Proximal Bone Loss," Stephen B Murphy, MD; Jose Rodriguez, MD.
The presence of a deficient or mechanically compromised proximal femur represents a particular challenge to revision total hip arthroplasty. This article details the results of reconstructing these challenging cases using a modular, tapered, and distally fixed femoral stem component that allows independent control of length, offset, and anteversion of the femur. Mid-term results suggest that distal fixation in the presence of a deficient or mechanically compromised femur is a reliable solution to these difficult problems.
The Journal of Arthroplasty, Volume 24, Issue 5, Pages 751-758 (August 2009). "Two-Year to Five-Year Follow-Up of Femoral Defects in Femoral Revision Treated With the Link MP Modular Stem," Jose A. Rodriguez, MD; Robert Fada, MD; Steven B. Murphy, MD; Vijay J. Rasquinha, MD; Chitranjan S. Ranawat, MD.
Femoral deficiency has been shown to adversely affect the results of revision total hip arthroplasty. Tapered titanium modular stems allow distal fixation of the fluted, conical portion of the implant in the setting of proximal bone loss. One hundred two consecutive hips with proximal bone loss underwent revision femoral reconstruction between 1998 and 2002 at 3 centers using the Link MP modular stem. Forty-three hips had Mallory type 3C femoral deficiency. Ninety-seven hips were observed for an average of 45 months (range, 24-72; median, 36 months). Clinically, mean Harris hip score improved from 36 to 84 (range, 54-99). Radiographically, 93 hips were considered stable, with no circumferential lucencies at the distal fixation surface. Three hips migrated and required revision, along with one periprosthetic fracture. Five other hips had nonprogressive migration of 1 to 2 mm.
The Journal of Arthroplasty, article in press, (published online 10 February 2010). "Minimum 5-Year Follow-Up of a Cementless, Modular, Tapered Stem in Hip Revision Arthroplasty," Rüdiger J. Weiss, MD, PhD; Mats O. Beckman, MD; Anders Enocson, MD; Anders Schmalholz, MD, PhD; André Stark, MD, PhD.
Hip revision surgery with a cementless tapered femoral component can provide axial and rotational stability in patients with compromised proximal bone stock. This study includes 90 cases revised with the Link MP (Waldemar Link, Hamburg, Germany) prosthesis. The median age at surgery was 72 (38-89) years. Aseptic loosening (70%) and periprosthetic fracture (22%) were common indications for surgery. Sixty-three patients (70%) were followed clinically with a median of 6 (5-11) years of follow-up. All other patients were followed through the Swedish Hip Register. The 5-year survival rate was 98% with stem removal and 90% with any reoperation as the end point. Complications included hip dislocation in 17 (19%) patients. The median Harris hip score was 78 (16-100) points, and the median radiographic stem migration was 2.7 mm at follow-up.
The Journal of Arthroplasty, Volume 18, Issue 3, Supplement, Pages 94-97 (April 2003). "A Modular Distal Fixation Option for Proximal Bone Loss in Revision Total Hip Arthroplasty: A 2- to 6-year Follow-up Study," Louis M. Kwong, MD; A.John Miller, MD; Phillipp Lubinus, MD.
Proximal femoral bone deficiency in the failed total hip arthroplasty (THA) is addressed with difficulty using proximally fixed implants. The Link MP reconstruction hip stem is proximally modular but utilizes distal fixation. This series consists of 143 patients from 3 clinical sites. Of the patients, 81 were women. The average follow-up time was 40 months, and the average patient age was 67 years. The preoperative diagnoses included 108 cases of aseptic loosening and 14 periprosthetic fractures. Clinical follow-up of all patients included radiographic assessment of the hip. This study found a 97.2% survival rate. The average subsidence was 2.1 mm. The average postoperative Harris hip score was 92. Complications included 7 wound infections and 4 deep venous thromboses. We found that the Link MP hip stem allows successful revision THA reconstruction of the proximally compromised femur. Good to excellent functional restoration and pain relief is achievable.
Other Relevant Studies
The studies below utilized other similar revision stems on the market. These abstracts are included for additional context and to provide a base familiarity with competitive offerings in the modular, tapered, distally-fixed revision hip market.
The Journal of Arthroplasty, Volume 25, Issue 3, Pages 348-354 (April 2010). "Revision Total Hip Arthroplasty Using a Modular Tapered Stem With Distal Fixation: Good Short-Term Results in 125 Revisions," Ole Ovesen, MD; Claus Emmeluth, MD, PhD; Christian Hofbauer, MD: Søren Overgaard, MD, PhD.
After 2 to 7 years we reviewed 125 prosthetic hip arthroplasty stem revisions using a modular tapered stem with distal fixation. Median age of these patients was 68 (33-92) years. Baseline and follow-up data were registered prospectively according to the Danish Hip Arthroplasty Registry. Survival, free of any re-revision, was 94%. Harris Hip Score improved from average 44 to 85. Bony regeneration was an early and significant finding in most cases. Complications included 4 (3%) fractures intraoperatively and 8 (6%) dislocations, 4 (3%) deep infections, and 1 (1%) stem fracture. This modular taper system is very versatile, can be used in most femoral revision cases, and allows rapid bone remodeling. We did not find an increased number of complications compared to the literature. Further long-term follow-up, however, is essential.
The Journal of Arthroplasty, Volume 25, Issue 6, Pages 926-931 (September 2010). "Influence of Technique with Distally Fixed Modular Stems in Revision Total Hip Arthroplasty," Preetesh D. Patel, MD; Alison K. Klika, MS; Trevor G. Murray, MD; Karim A. Elsharkawy, MD; Viktor E. Krebs, MD; Wael K. Barsoum, MD.
Distally fixed modular implants have seen a recent increase in use, to manage proximal femoral bone loss often encountered during revision total hip arthroplasty (THA). Forty-three distally fixed modular stems implanted at our institution between 1999 and 2006 were clinically and radiographically reviewed. These patients had either a minimum 2-year follow-up (average, 2.4 years; range, 2-5.6 years) or failure (ie, explant or re-revision required). Eleven stems subsided, and 4 were rerevised (n = 4), for a rate of 9.3%. All revised stems were radiographically undersized, emphasizing the importance of the technique. Although being a valuable option in revision THA, these stems are not free of complications. The high rate of subsidence encountered in our early experience shows that there is a learning curve. This complication is preventable by avoiding undersizing.
SOT, 2/2002, Volume 25, p. 175. "Cementless Modular Hip Revision Arthroplasty
with the MRP Titanium Stem," Alexander Schuh, Sari Salminen, Ulrich Holzwarth, Günther Zeiler.
As the number of primary THRs of younger patients with high physical demands increases, the amount of revision operations also grows. Bone loss with severe osteolysis, joint instability, function of pelvitrochanteric muscles, leg length discrepancy, a proper antetorsion angle, cement mantles, periprosthetic fractures, or infections are problems to be considered in revision arthroplasties of the hip. A femoral prosthesis stem should guarantee the proximal transmission of force. The aim of this prospective study was to scrutinize the outcome of hip joint revisions using the modular revision prosthesis (MRP) titanium stem. The mean follow-up time for all 72 patients including 34 men and 38 women was 3.6 years (range, 2-7 years). The mean age of the patients at the time of the operation was 67.3 years (range, 45.5- 88.6 years). The indication for the hip revision arthroplasty was in 56 cases an aseptic loosening of cup and stem, in 14 cases an aseptic loosening of the stem, and a Girdlestone hip in 2 cases. The Harris hip score improved from 54.9 to 92.2. In all cases the spontaneous refill of bony defects was detected with remodeling of bone without any bone transplantation. The most common intraoperative complication was a femoral fissure or fracture during the stem removal (4 cases), the most common early postoperative complication a deep venous thrombosis (2 cases), and the most common late postoperative complications a recurrent dislocation (2 cases), a subsidence of the stem (2 cases), or a persisting infection necessitating the removal of the prosthesis (2 cases). The revision rate was 4.17 %. With the MRP titanium prosthesis a stable primary fixation with a reduced risk of dislocation could be achieved. Modularity of the prosthesis allows an optimal lever arm to improve the function of pelvitrochanteric muscles, to equalize leg length discrepancy, and to choose a proper antetorsion angle. A total hip replacement (THR) is one of the most successful principles in orthopedic surgery. As the number of primary THRs of younger patients with high physical demands increases, the amount of revision operations also grows. Bone loss with severe osteolysis, joint instability, function of pelvitrochanteric muscles, leg length discrepancy, a proper antetorsion angle, cement mantles, periprosthetic fractures, or infections are problems to be considered in revision arthroplasties of the hip. The osseous anchoring is essential for the function of THR. Bone defects need long revision stems. According to recently published good results in hip revision surgery, there is a tendency for cementless revision arthroplasty. A femoral prosthesis stem should guarantee the proximal transmission of force to avoid the atrophy of the proximal femur caused by stress shielding. Still sometimes only a distal fixation can be achieved because of the considerable bone desorption. A modular revision prosthesis can resolve these problems. In order to improve the durability of a revision prosthesis, wear has to be reduced by diminishing e.g. the friction between the femoral head and the acetabular cup, and the morse taper junctions. Although some negative effects of the modularity regarding morse taper junctions have been published, most authors have found no disadvantages.
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