Complex revision total hip arthroplasty with modular stems at a mean of 14 years

Revision Hip Arthroplasty Using a Porous-coated or Taper ZMR Implant: Minimum 10-year Follow-up of Implant Survivorship

INTRODUCTION

The Zimmer Modular Revision hip (ZMR) system is available in two stem options, a porous-coated cylindrical (PCM) and a taper (TM) stem. Several concerns have been reported regarding modular implants. Specifically, because of early junctional fractures, the ZMR system was redesigned with a wider modular interface. As such, we designed a study assessing long-term ZMR survivorship and functional and radiographic outcomes.

METHODS AND MATERIALS

A search of our institutional research database was performed. A minimum 10-year follow-up was selected. The following two cohorts were created: PCM and TM stems. The Kaplan-Meier survival analysis was performed, and causes of stem failure requiring revision surgery were collected. Functional outcomes as per the Harris Hip Score and radiographic stem stability were assessed as per the Engh classification.

RESULTS

A total of 146 patients meeting the inclusion criteria were available for follow-up (PCM = 68, TM = 78). The mean follow-up was 13.4 years clinically and 11.1 years radiographically for the PCM cohort. Similarly, the TM cohort had a follow-up of 11.1 years clinically and 10.5 years radiographically. The Kaplan-Meier survivorships were 87.1% and 87.8% at 15 years for the PCM and TM cohorts, respectively. The most common cause of failure requiring revision surgery overall was aseptic loosening (PCM = 1.4%, TM = 5.6%). The mean postoperative Harris Hip Score was as follows: PCM = 71.2 and TM = 64.7. Engh type I or II stem ingrowth was as follows: PCM = 85% and TM = 68%.

DISCUSSION

Good survivorship using the ZMR stem system can be expected at up to 15 years. Aseptic loosening remains the most commonly encountered problem for both PCM and TM stems. Previously identified modular junctional weakness seem to have been addressed.

Femoral Component Revision of Total Hip Arthroplasty

Modern primary total hip arthroplasty (THA) is among the most successful operations in medicine. It has been a consistently effective treatment for end-stage osteoarthritis of the hip. With the increasing number of primary THA procedures being performed and the decreasing age of patients undergoing the procedure, there is an inevitable associated increase in revision burden for arthroplasty surgeons. Revision THA is most often indicated for instability, aseptic loosening, osteolysis, infection, periprosthetic fracture, component malposition, and catastrophic implant failure. Understanding the etiology of THA failure is essential for guiding clinical decision making. Femoral component revision presents a complex challenge to the arthroplasty surgeon because of modern implant design as well as bone loss in the proximal femur. Thorough patient evaluation, defect classification, and well-executed surgical reconstruction based on comprehensive preoperative planning may determine the postoperative results. Knowledge of various reconstructive options and the indications for each is necessary to achieve a successful outcome. This article highlights the most common indications for revision after THA and offers recommendations for how to approach revision of the femoral component. Specifically, the authors review preoperative assessment, common classification systems for femoral deficiency, techniques for component extraction, and modalities of femoral component fixation. [Orthopedics. 2016; 39(6):e1129-e1139.].

REVISION TOTAL HIP ARTHROPLASTY USING A MODULAR CEMENTLESS DISTAL FIXATION PROSTHESIS: THE ZMR(®) HIP SYSTEM. CLINICAL AND RADIOGRAPHIC ANALYSIS OF 30 CASES

Objective: To evaluate the clinical and radiographic results from 30 cases of revision of total hip arthroplasty using a modular cementless distal fixation prosthesis: the ZMR^® Hip System. Method: Between July 2005 and December 2008, 30 operations were performed, on 14 men and 14 women. Two male patients had bilateral surgery. The mean age was 59.2 years (29-81 years), with a mean follow-up of 24 months. The Paprosky classification was used for periprosthetic bone loss, and the Harris Hip Score (HHS) was used to evaluate clinical results. On radiographs, distal migration of the femoral stem was defined in accordance with Sporer. Proximal bone remodeling was classified using the Callaghan criteria. Results: The mean preoperative HHS was 39, and there was a significant increase to 93 points in the final evaluation, which indicated excellent clinical results. No femoral stem migration greater than 5 mm (Sporer) was observed on radiographs, thus suggesting that all the femoral prostheses presented osseointegration and remained stable from the time of the surgery until the final evaluation. The proximal femoral remodeling was either type B or type C in 29 hips, according to Callaghan. Seven patients had complications, but without interfering with osseointegration of the femoral components. Conclusion: Our results from revision of total hip arthroplasty using the ZMR^® Hip System were extremely encouraging, and all the components became osseointegrated and remained fixed at the time of the final evaluation.

Revision total hip arthroplasty using cemented collarless double-taper femoral components at a mean follow-up of 13 years (8 to 20): an update

The outcome of 219 revision total hip arthroplasties (THAs) in 98 male and 121 female patients, using 137 long length and 82 standard length cemented collarless double-taper femoral stems in 211 patients, with a mean age of 72 years (30 to 90) and mean follow-up of six years (two to 18) have been described previously. We have extended the follow-up to a mean of 13 years (8 to 20) in this cohort of patients in which the pre-operative bone deficiency Paprosky grading was IIIA or worse in 79% and 73% of femurs with long and standard stems, respectively. For the long stem revision group, survival to re-revision for aseptic loosening at 14 years was 97% (95% confidence interval (CI) 91 to 100) and in patients aged > 70 years, survival was 100%. Two patients (two revisions) were lost to follow-up and 86 patients with 88 revisions had died. Worst-case analysis for survival to re-revision for aseptic loosening at 14 years was 95% (95% CI 89 to 100) and 99% (95% CI 96 to 100) for patients aged > 70 years. One additional long stem was classified as loose radiographically but not revised. For the standard stem revision group, survival to re-revision for aseptic loosening at 14 years was 91% (95% CI 83 to 99). No patients were lost to follow-up and 49 patients with 51 hips had died. No additional stems were classified as loose radiographically. Femoral revision using a cemented collarless double-taper stem, particularly with a long length stem, and in patients aged > 70 years, continues to yield excellent results up to 20 years post-operatively, including in hips with considerable femoral metaphyseal bone loss.

Proximal femoral arthroplasty in patients undergoing revision hip arthroplasty

Bone loss represents one of the greatest challenges in revision joint surgery. A retrospective review was conducted of both radiographic and clinical outcomes of eleven patients who underwent revision arthroplasty using a long extensively porous coated cylindrical femoral component. All patients' femurs presented with severe proximal femoral bone loss (Paprosky class IIIB and IV). With a mean follow-up of 8 years (2 to 14) we report no femoral revisions and one acetabular revision to a constrained cup secondary to instability. All patients were clinically and radiographically stable. We did not observe any issue with proximal stress shielding or component loosening. The article reports that in patients with severe proximal femoral bone loss, extensively porous-coated non-modular stems are a viable option offering stable and predictable outcomes.

Unique failure mechanism of a femoral component after revision total hip arthroplasty

As the prevalence of revision total hip arthroplasty increases, the mechanisms of failure of these revisions have become better delineated. Several studies have indicated infection, instability, and aseptic loosening to be the more common mechanisms of failure in revision surgery. However, with increasing numbers of revisions performed, unique mechanisms of failure are being seen, likely related to the implants that are used in the revision setting. Revision implants offer certain advantages over primary implants with the use of modular components. The revision implants allow the surgeon to increase offset and leg length with modular femoral bodies and necks. However, these modular junctions represent additional areas for implant failure. These new methods of failure associated with modular implants are slowly presenting as the use of these implants continues to increase. The authors recently encountered a mechanism of failure that, to their knowledge, has not been described in the literature. They report a 57-year-old man with dissociation of the proximal body from the diaphyseal component of a Wright Medical Link (Memphis, Tennessee) stem prosthesis. The patient presented with an audible click on physical examination, and radiographs confirmed dissociation of the proximal body. The intraoperative findings, treatment method, and proposed mechanisms for this type of failure are presented, as well as insight into potential ways to avoid this type of failure.

Revision total hip arthroplasty using a modular femoral implant in Paprosky type III and IV femoral bone loss

The purpose of this study was to compare results of patients with Paprosky type I and II femoral defects vs type IIIA, IIIB, and IV defects in patients undergoing revision hip arthroplasty. There were 64 patients in the group with type I and II defects with an average age of 68 years. There were 52 patients with Paprosky type IIIA, IIIB, and IV defects with an average age of 67 years. There were 8 intraoperative fractures in the type III and IV group, whereas there were 9 in the type I and II group. There were no differences between the 2 groups with respect to subsidence, loosening, dislocation, infection, and medical complications. Survivorship for the whole group was 96.9% at 5 years. Modular femoral implants provide several intraoperative options to restore leg length, offset, and stability despite femoral defects. We did not realize a higher failure rate in patients with type III or IV defects.

Clinical experience in femoral revision with the modular Profemur R stem

The application of modular femoral stems is constantly increasing in revision hip surgery. From March 2001 to March 2006, we employed the Profemur R modular stem in 35 cases of femoral component revision (31 first revisions and 4 re-revisions). The reasons for revision surgery included aseptic loosening in 17 cases, periprosthetic femoral fracture in 8 cases, stem fracture in 3 cases, septic loosening in 2 cases and recurrent dislocation in 1 case. According to the Merle d'Aubugne-Postel score clinical results were very good in 11 cases, good in 9 cases, medium in 5 cases, fair in 4 cases and poor in 4 cases. The main complications included 2 intraoperative diaphyseal fractures treated with multiple cerclage wires and 2 early infections treated with debridement and prolonged antibiotic therapy. One fracture healed in association with temporary wound discharge, and the other resulted in non-union with a femoral varus deformity. This required revision with internal fixation (LCP plate) at 3 months, with a successful result. In one case of stem subsidence femoral revision with a larger Profemur R implant was required. In our retrospective study the Profemur R modular stem has been an effective prosthetic system for femoral reconstruction in case of loosening with Paprosky grade III bone loss and following periprosthetic femoral fractures.

Long-term comparison of porous and hydroxyapatite sleeves in femoral revision using the S-ROM modular stem

We prospectively evaluated the results of a single-surgeon series of 28 femoral revision arthroplasties using the S-ROM modular stem with either a porous-coated sleeve (15 hips) or a hydroxyapatite-coated sleeve (13 hips) after a mean of 10 years (range, 8-14 years). Three femoral stems underwent repeat femoral revision for aseptic loosening in association with Paprosky type III bone defects after a mean of 9 years in vivo (range, 8-10 years). One on these 3 had a porous-coated sleeve and the other 2 had a hydroxyapatite-coated sleeve. With repeat revision for any reason as the end point, femoral component survival was 83.8% at 10 years for the entire series, and 93.3% for the porous-coated sleeve group and 76.2% for the hydroxyapatite-coated sleeve group, respectively (log-rank test, P=0.588). No significant difference was detected between the 2 groups regarding postoperative Harris hip scores, bone ingrowth, stress-shielding, osteolysis, or complication rates. At a mean of 10 years postoperatively, hydroxyapatite-coated sleeves offered no clinical benefit over porous-coated sleeves for revision hip replacement using the S-ROM modular stem. Our findings also indicate that hydroxyapatite-coated sleeves did not reduce late mechanical stem failures in cases with a deficient femur.

Revision hip arthroplasty: infection is the most common cause of failure

BACKGROUND

Revision total hip arthroplasty (THA), although relieving pain and restoring function, fails in some patients. In contrast to failures in primary THA, the frequency of the causes of failure in revision THA has been less well established.

QUESTIONS/PURPOSES

We therefore determined the rate of each failure mode and the survivorship of revision THAs.

METHODS

We retrospectively reviewed the charts of 1366 revision THAs performed between 2000 and 2007. There were 609 (44.5%) men and 757 (55.5%) women with a mean age of 66 years. The indications for the revision surgery were mainly aseptic loosening (51%), instability (15%), wear (14%), and infection (8%). The minimum followup was 1 day (mean, 5.5 years; range, 1 day to 9 years).

RESULTS

Two hundred fifty-six of the revisions (18.7%) failed with an average time to failure of 16.6 months (range, 1 day to 7.5 years). Among 256 failed hips, infection was the most common cause of failure (30.2%) followed by instability (25.1%) and aseptic loosening (19.4%). At 5 years, the survivorships of septic and aseptic groups were 67% and 84.8%, respectively. Revision for infection or instability appears to have a considerably lower survivorship when compared to revision for aseptic causes.

CONCLUSIONS

The lower survivorship of revision for infection or instability highlights the importance of implementing better preventative methods that can minimize the impact of these two major causes of failure.

LEVEL OF EVIDENCE

Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Revision total hip arthroplasty with a porous-coated modular stem: 5 to 10 years follow-up

The ZMR porous stem is a modular cylindrical porous-coated femoral stem for revision THA. The objective of this study was to evaluate the clinical and radiographic outcomes of this stem at midterm followup. We prospectively reviewed 69 patients (72 femoral revisions) treated with the stem. The indication for revision was aseptic loosening in 61 (85%), periprosthetic fractures in five (7%), infection in three (4%), dislocation in two (3%), and fractured stem in one (1%). Minimum followup was 60 months (mean, 85 months; range, 60-114 months). The survival rate with revision for any reason as an end point was 93.8%. Mean preoperative Harris hip score was 39 points, and mean Harris hip score at last followup was 72 points. Four (5.5%) stems required rerevision, two (2.8%) for loosening, one (1.4%) for fracture at the modular junction, and one (1.4%) for infection. Subsidence occurred in eight (11%) patients, in the range of 5 to 25 mm. Two (2.89%) of the stems that subsided were symptomatic and progressive. The ZMR porous stem is a versatile system that offers a reliable fixation and an off-the-shelf solution for a multitude of femoral reconstruction challenges.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Short-term results of the S-ROM-A femoral prosthesis operative strategies for Asian patients with osteoarthritis

The S-ROM-A femoral prosthesis (DePuy, Warsaw, IN) is a modular cementless femoral stem system that was developed to adapt to hip joint disorders of Asian patients. Clinical results of total hip arthroplasties using the S-ROM-A femoral prosthesis were evaluated in 68 hips. The average age at the time of surgery was 57.1 years. The mean follow-up period was 27.8 months. The Harris hip score improved from 47.1 points preoperatively to 91.4 points at final follow-up. No dislocations were observed. Implant fixation was good without any evidence of osteolysis or loosening. The S-ROM-A femoral prosthesis fitted well for Asian patients who often have osteoarthritis secondary to developmental dysplasia of the hip, by providing a shorter stem and greater variety in the neck shape of the stem with a smaller diameter.

Stem modularity alone is not effective in reducing dislocation rate in hip revision surgery

Background

Dislocation is a serious complication following total hip arthroplasty (THA). Femoral revision using monoblock components has been associated with high incidence of subsidence and dislocation. Advantages of modular stems in THA have long been debated. The aim of this retrospective study is to assess the capability of an uncemented modular stem in decreasing the incidence of early dislocation subsequent to revision THA.

Materials and methods

We evaluated the dislocation rate during the first 2 years following revision surgery in two groups of patients who were treated by implantation of a cementless tapered femoral prosthesis; a standard-modularity stem (Wagner SL) and an increased-modularity stem (Profemur R) were used, respectively, in 66 hips (group I, 64 patients) and 102 hips (group II, 97 patients). Group I consisted of 47 females and 17 males with average age of 66 years (range 29–84 years). Group II included 60 females and 37 males with average age of 70 years (range 48–89 years).

Results

Dislocation occurred in six hips (9.1%) of group I and in seven hips (6.8%) of group II (P = 0.401). Dislocations were observed early in both groups, except one hip in group II that dislocated 434 days postoperatively and required surgical reduction. All other dislocations were treated by closed reduction. No recurrence was observed.

Conclusions

The use of an increased-modularity revision stem alone did not prove to be effective in reducing the risk of postoperative dislocation.

[Revision hip arthroplastiy of the hip joint. Revision of the femur: which implant is indicated when?]

Cementless revision hip arthroplasty is described as state of the art, especially in cases of advanced bone loss of the femur. A requirement for a good result from cement-free revision hip arthroplasty is classification of the bone defect and the presence of a mechanically stable anchorage in the area of the original implant or, in cases of bone defects, distal to the original area in stable diaphyseal bone. The possibility of the accumulation of autografts or allogeneic osseous grafts and the entire removal of the cement and debris has been postulated. The advantages of cementless revision hip arthroplasty include regeneration of the bone stock and the often available modularity of the revision hip system, which allows adaptation to different bone configurations and also allows a partial change of the prosthesis in rerevision cases, such as in cases of sintering or derotation. Cemented revision arthroplasty should be done only in special cases, such as with marginal bone defects or for older patients with a short life expectancy.

Why revision total hip arthroplasty fails

Current outcomes data on revision total hip arthroplasty focuses on specific implants and techniques rather than more general outcomes. We therefore examined a large consecutive series of failed THAs undergoing revision to determine if survivorship and modes of failure differ in comparison to the current data. We retrospectively reviewed the medical records of 1100 revision THAs. The minimum followup was 2 years (mean, 6 years; range, 0-20.4 years). Eighty-seven percent of revision total hips required no further surgery; however, 141 hips (13%) underwent a second revision at a mean of 3.7 years (range, 0.025-15.9 years). Seventy percent (98 hips) had a second revision for a diagnosis different from that of their index revision, while 30% (43 hips) had a second revision for the same diagnosis. The most common reasons for failure were instability (49 of 141 hips, 35%), aseptic loosening (42 of 141 hips, 30%), osteolysis and/or wear (17 of 141 hips, 12%), infection (17 of 141 hips, 12%), miscellaneous (13 of 141 hips, 9%), and periprosthetic fracture (three of 141 hips, 2%). Survivorship for revision total hip arthroplasty using second revision as endpoint was 82% at 10 years. Aseptic loosening and instability accounted for 65% of these failures.

LEVEL OF EVIDENCE

Level IV, therapeutic (retrospective) study. See the Guidelines for Authors for a complete description of levels of evidence.