Do revised hip resurfacing arthroplasties lead to outcomes comparable to those of primary and revised total hip arthroplasties?

Conversion of hip resurfacing to total hip arthroplasty: is the outcome closer to primary or revision total hip arthroplasty?

BACKGROUND

Along with the advent of newer bearings, hip resurfacing (HR) is gaining renewed interest as a bone sparing alternative to conventional total hip arthroplasty (THA) in young patients. However, the outcome of conversion of failed HR to THA (HRc) remains sparsely described. This study aimed to compare the outcomes and complication rates of HRc to those of primary (pTHA) and revision THA (rTHA) to find out to which group HRc is most comparable.

HYPOTHESIS

The study hypothesis was that the outcomes and complications rates of HRc were closer to those of pTHA than rTHA.

MATERIALS AND METHODS

Between 2001 and 2011, a continuous series of 207 HR were prospectively included in our institutional registry and retrospectively analyzed. Out of them, 17 HR (8%) were converted to THA. Propensity scores were used to match patients in the HRc group to the pTHA and the rTHA groups using a greedy 1:3 matching procedure (51 pTHA and 51 rTHA). Clinical and radiographic outcomes, perioperative data and complications were analyzed and compared between the three groups.

RESULTS

No significant difference between HRc and pTHA was observed in terms of clinical and functional outcomes, duration of surgery, acetabular component diameter and length of hospital stay (p = 0.13 to 0.94). Perioperative blood loss was significantly lower for pTHA than for HRc (p = 0.01). HRc demonstrated significantly higher HHS and HOOS scores than for rTHA at one year (p = 0.03 and p < 0.01, respectively). Duration of surgery was significantly lower in HRc compared to rTHA (p = 0.02) while length of hospital stay was similar (p = 0.84). Complication rate was significantly higher in the rTHA group, compared to HRc and pTHA groups (37.3 vs. 29.4 vs. 11.8%, p = 0.01).

CONCLUSION

This study demonstrated that the clinical and functional outcomes of HRc were closer to those of pTHA than those of rTHA, though complication rate was higher than for pTHA.

LEVEL OF EVIDENCE

III; Retrospective comparative study.

Outcome of hip resurfacing revision through the Hueter-anterior approach

BACKGROUND

The Hueter-Anterior Approach (HAA) with its limited soft tissue and internervous dissection has been shown to be an effective approach for primary total hip and hip resurfacing arthroplasty (HRA). The purpose of this study is to evaluate the clinical outcome of patients requiring revision of HRA to total hip replacement using the HAA, assessing function and complications.

METHODS

We performed a retrospective review of a prospectively maintained research database. Between 2006 and 2015, 555 primary metal-on-metal (MoM) HRAs were performed via the HAA; we identified 33 hips in 30 patients that required revisions for aseptic causes to THA: aseptic loosening of acetabulum in 12 and femoral in 7, 10 for pseudotumour/ALTR, 4 for femoral neck fracture. All revision surgeries were performed through a HAA by a single surgeon who had also performed the index operation. PROMs were collected preoperatively and yearly at various timepoints postoperatively.

RESULTS

The mean age at time of revision was 48.9 years (±5.3 SD) for 22 males (67%) and 11 females (33%). The mean time to revision surgery/failure of hip resurfacing was 3.3 years (±2.4 SD). There were 5 major reoperations with 3 infections, 1 acetabular loosening and 1 trunnionosis. There were significant improvements in multiple PROMs.

CONCLUSIONS

The HAA is a viable surgical approach for revision of HRA with smaller initial HRA acetabular components generally requiring a relatively larger acetabular compoent at time of revision. Patients reported improvement in symptoms and function and a lower risk of subsequent reoperation than what has previously been reported for failed MoM bearings.

Hueter Anterior Approach for Metal-on-Metal Hip Resurfacing Arthroplasty: 555 Cases at a Minimum Five-Year Follow-Up

BACKGROUND

Purpose of this study was to determine implant survivorship and resultant outcomes, including modes of failure, for metal-on-metal hip resurfacing through the Hueter anterior approach (HAA).

METHODS

Retrospective review of cases from 2006 to 2015, resulted in 555 metal-on-metal hip resurfacing via HAA, mean age 49.4 ± 6.9 years and mean BMI 28.1 ± 5.3. Kaplan-Meier curves were used to assess implant survivorship. Evaluation of technique was based on radiographic assessment of component position at 6 weeks. Patient-reported outcome measures were assessed using 12-Item Short Form Survey 12, University of California Los Angeles activity, Western Ontario and McMaster Universities Osteoarthritis Index, and hip disability osteoarthritis outcome scores.

RESULTS

At a mean follow-up of 9.18 years, survivorship was 95.0% at 5 years (95% CI: 93.2-96.8 years) and 92.5% at 10 years (95% CI: 90.0-95.0 years); men at 96.1% (95% CI: 94.3-97.9) and 93.8% (95% CI: 91.1-96.5), and women at 88.8% (95% CI: 81.9-95.7) and 85.6% (95% CI: 77.6-93.6), 5 and 10 years, respectively (P = .033). There were 37 revisions to total hips (7%) at a mean time of 3.3 years (SD 2.7). Indications for revision were aseptic loosening of acetabular (n = 12) and femoral component (n = 7) and pseudotumor (n = 6). Radiographic parameters were respectable and consistent, median acetabular inclination angle 41.2° and femoral stem shaft angle 137.7°. Patient-reported outcome measure scores significantly improved and remained stable at 2 and 5 years postoperatively.

CONCLUSION

Although choice of surgical approach should always be based on surgeon's technical expertise, this study has shown that HAA is safe and effective for hip resurfacing. Mindful attention to long-term metal ion exposure must still be considered.

Patient-reported outcomes after primary or revision total hip arthroplasty: A propensity score-matched Asian cohort study

BACKGROUND

Few studies have compared patient-reported outcome measures (PROMs) between primary and revision total hip arthroplasty (THA). We investigated and compared PROMs between propensity score-matched primary and revision THA in an Asian cohort.

METHODS

The Oxford Hip Score (OHS) and University of California-Los Angeles (UCLA) activity score, satisfaction score, and Short Form-12 Health Survey (SF-12) were compared between 110 primary and 110 revision THAs after propensity score matching. Multivariate analyses were performed to determine which factors, including patients' demographics, indication for revision, and pre-operative PROMs, were associated with post-operative PROMs in the revision THA cohort.

RESULTS

The revision THA cohort demonstrated significantly lower post-operative OHS, UCLA activity score, and satisfaction score (10% decrease on average) than those in the primary THA cohort (P < .05). The difference in SF-12 mental component summary measure (MCS) between the two cohorts was statistically insignificant (P = .24). In multivariate analysis for the revision THA cohort, lower post-operative UCLA activity score was significantly associated with higher BMI and lower pre-operative UCLA activity score (P < .05).

CONCLUSION

Revision THA was associated with a modest but significant decrease in physical PROMs as compared with primary THA. Pre-operative UCLA activity score significantly affected the post-operative physical outcome measures in the revision THA cohort. However, post-operative SF-12 MCS was comparable between the primary and revision THA cohorts.

Superior patient reported outcome measures reported post Articular Surface Replacement (ASR) revision arthroplasty in the setting of an objective surgical indication

The Articular Surface Replacement (ASR) hip system displayed unexpectedly high failure rates. All patients who underwent revision arthroplasty at our institution were identified. Indications for revision were classified as objectively identifiable or performed for unexplained pain. Clinical outcomes, post ASR revision, were superior in cases where the aetiology for failure was identifiable. Pain and function improved reliably when a targeted objective indication was identified pre-revision, but failed to do so in cases of unexplained pain. Surgeons familiar with the results of this study will be empowered to discuss expectations and realistic outcomes with their patients undergoing complex revision arthroplasty cases.

Outcomes after revision of metal on metal hip resurfacing to total arthroplasty using the direct anterior approach

BACKGROUND

Function after revision total hip arthroplasty (THA) in failed metal-on-metal (MoM) hip resurfacing arthroplasty (HRA) is variable, but post-operative complication rates are reportedly high. We hypothesized HRA conversion to THA using the direct anterior approach (DAA) would be associated with optimal outcome.

METHODS

Seventeen MoM-HRAs in 15 patients (seven males, eight females) were revised through the DAA. The mean age was 45 years (28-59 yrs). The most common indications for revision were aseptic loosening of the acetabular component or of the femoral component and femoral neck fracture. In 16 hips, a conversion to a ceramic-on-ceramic (CoC) (13 hips) or to a metal-on polyethylene (MOP) (2), or to a large-head MoM (1) THA was done. An isolated femoral revision was done in one hip.

RESULTS

After 6.7 ± 3 years, no hip had required a re-revision. The Postel-Merle d'Aubigne (PMA) functional score improved from 9 (4-14) to 16 (12-18) (p < 0.001). An intra-operative fracture of the greater trochanter (one hip) and dysesthesia of the lateral femoral cutaneous nerve (four hips) were reported. Mean serum chromium concentration decreased from 33.2 μg/L (11.8-62 μg/L) pre-operatively to 5.8 μg/L (0.4-35.5 μg/L) post-operatively (p < 0.001), and mean serum cobalt concentration decreased from 35.8 μg/L (6.3-85.5 μg/L) to 4.7 μg/L (0.26-25.7 μg/L) (p = 0.003).

CONCLUSION

Revision of failed MoM-HRA using the DAA resulted in an acceptable clinical outcome, no specific complication and no further surgery. A consistent decline in serum ion levels may be expected following HRA conversion to THA.

Patient-reported outcomes after revision surgery compared to primary total hip arthroplasty

INTRODUCTION

Patients who undergo either primary or revision total hip arthroplasty (THA) mainly expect improvement in pain, function/activity and quality of life. The purpose of the study was to measure the degree of short-term and medium-term improvement and the differences in patient-reported outcome that can be expected in patients undergoing revision THA, compared to patients undergoing primary THA.

METHODS

In this study, the results of patient-reported outcome measurements were compared in 124 matched patients, who underwent revision surgery and primary THA between 01/2007 and 12/2009. Assessment was performed at short-term and medium-term follow-up and included the WOMAC score, the UCLA activity score and EuroQol scores.

RESULTS

6 months after revision THA, the mean total WOMAC score improved by 22.1 points, the UCLA activity score by 0.6 points and the EuroQol-Index by 0.2 points. After primary THA, the improvement was 41.4 points on the WOMAC, 1.1 points on the UCLA and 0.3 points on the EuroQol-Index. At medium-term follow-up, 3.6 years after revision surgery and 2.3 years after primary THA, patients undergoing revision THA showed significantly less overall improvement, as well as lower final outcome scores, than patients undergoing primary THA.

CONCLUSIONS

Patients undergoing revision arthroplasty, as well as patients undergoing primary THA, can expect major improvement in function, activity and quality of life postoperatively. However, overall level of improvement, as well as peak attainable outcome levels, are lower after revision surgery than after primary THA. Appropriate information for patients who undergo hip revision surgery is necessary in order to avoid unrealistic expectations and postoperative dissatisfaction.

A randomised controlled trial of cemented and cementless femoral components for metal-on-metal hip resurfacing: a bone mineral density study

The primary purpose of this study of metal-on-metal (MoM) hip resurfacing was to compare the effect of using a cementless or cemented femoral component on the subsequent bone mineral density (BMD) of the femoral neck. This was a single-centre, prospective, double-blinded control trial which randomised 120 patients (105 men and 15 women) with a mean age of 49.4 years (21 to 68) to receive either a cemented or cementless femoral component. Follow-up was to two years. Outcome measures included total and six-point region-of-interest BMD of the femoral neck, radiological measurements of acetabular inclination, neck-shaft and stem-shaft angles, and functional outcome scores including the Harris hip score, the Western Ontario and McMaster Universities Osteoarthritis Index and the University of California at Los Angeles activity scale. In total, 17 patients were lost to follow-up leaving 103 patients at two years. There were no revisions in the cementless group and three revisions (5%) in the cemented group (two because of hip pain and one for pseudotumour). The total BMD was significantly higher in the cementless group at six months (p < 0.001) and one year (p = 0.01) than in the cemented group, although there was a loss of statistical significance in the difference at two years (p = 0.155). All patient outcomes improved significantly: there were no significant differences between the two groups. The results show better preservation of femoral neck BMD with a cementless femoral component after two years of follow-up. Further investigation is needed to establish whether this translates into improved survivorship.

Surface replacement conversion: results depend upon reason for revision

Surface hip replacement (SHR) is generally used in younger, active patients as an alternative conventional total hip replacement in part because of the ability to preserve femoral bone. This major benefit of surface replacement will only hold true if revision procedures of SHRs are found to provide good clinical results. A retrospective review of SHR revisions between 2007 and 2012 was presented, and the type of revision and aetiologies were recorded. There were 55 SHR revisions, of which 27 were in women. At a mean follow-up of 2.3 years (0.72 to 6.4), the mean post-operative Harris hip score (HHS) was 94.8 (66 to 100). Overall 23 were revised for mechanical reasons, nine for impingement, 13 for metallosis, nine for unexplained pain and one for sepsis. Of the type of revision surgery performed, 14 were femoral-only revisions; four were acetabular-only revisions, and 37 were complete revisions. We did not find that clinical scores were significantly different between gender or different types of revisions. However, the mean post-operative HHS was significantly lower in patients revised for unexplained pain compared with patients revised for mechanical reasons (86.9 (66 to 100) versus 99 (96 to 100); p = 0.029). There were two re-revisions for infection in the entire cohort. Based on the overall clinical results, we believe that revision of SHR can have good or excellent results and warrants a continued use of the procedure in selected patients. Close monitoring of these patients facilitates early intervention, as we believe that tissue damage may be related to the duration of an ongoing problem. There should be a low threshold to revise a surface replacement if there is component malposition, rising metal ion levels, or evidence of soft-tissue abnormalities.

Metal-on-metal hip resurfacing compared with 28-mm diameter metal-on-metal total hip replacement: a randomised study with six to nine years' follow-up

A total of 219 hips in 192 patients aged between 18 and 65 years were randomised to 28-mm metal-on-metal uncemented total hip replacements (THRs, 107 hips) or hybrid hip resurfacing (HR, 112 hips). At a mean follow-up of eight years (6.6 to 9.3) there was no significant difference between the THR and HR groups regarding rate of revision (4.0% (4 of 99) vs 5.8% (6 of 104), p = 0.569) or re-operation rates without revision (5.1% (5 of 99) vs 2.9% (3 of 104), p = 0.428). In the THR group one recurrent dislocation, two late deep infections and one peri-prosthetic fracture required revision, whereas in the HR group five patients underwent revision for femoral head loosening and one for adverse reaction to metal debris. The mean University of California, Los Angeles activity scores were significantly higher in HR (7.5 (sd 1.7) vs 6.9 (sd 1.7), p = 0.035), but similar mean Western Ontario and McMaster Universities Osteoarthritis Index scores were obtained (5.8 (sd 9.5) in HR vs 5.1 (sd 8.9) in THR, p = 0.615) at the last follow-up. Osteolysis was found in 30 of 81 THR patients (37.4%), mostly in the proximal femur, compared with two of 83 HR patients (2.4%) (p < 0.001). At five years the mean metal ion levels were < 2.5 μg/l for cobalt and chromium in both groups; only titanium was significantly higher in the HR group (p = 0.001). Although revision rates and functional scores were similar in both groups at mid-term, long-term survival analysis is necessary to determine whether one procedure is more advantageous than the other.

The Canadian Arthroplasty Society’s experience with hip resurfacing arthroplasty

The purpose of this study was twofold: first, to determine whether the five-year results of hip resurfacing arthroplasty (HRA) in Canada justified the continued use of HRA; and second, to identify whether greater refinement of patient selection was warranted.

This was a retrospective cohort study that involved a review of 2773 HRAs performed between January 2001 and December 2008 at 11 Canadian centres. Cox’s proportional hazards models were used to analyse the predictors of failure of HRA. Kaplan–Meier survival analysis was performed to predict the cumulative survival rate at five years. The factors analysed included age, gender, body mass index, pre-operative hip pathology, surgeon’s experience, surgical approach, implant sizes and implant types. The most common modes of failure were also analysed.

The 2773 HRAs were undertaken in 2450 patients: 2127 in men and 646 in women. The mean age at operation was 50.5 years (sd 8.72; 18 to 82) and mean follow-up was 3.4 years (sd 2.1; 2.0 to 10.1). At the last follow-up a total of 101 HRAs (3.6%) required revision. Using revision for all causes of failure as the endpoint, Kaplan–Meier survival analysis showed a cumulative survival of 96.4% (95% confidence interval (CI) 96.1 to 96.9) at five years. With regard to gender, the five-year overall survival was 97.4% in men (95% CI 97.1 to 97.7) and 93.6% in women (95% CI 92.6 to 94.6). Female gender, smaller femoral components, specific implant types and a diagnosis of childhood hip problems were associated with higher rates of failure. The most common cause of failure was fracture of the femoral neck, followed by loosening of the femoral component.

The failure rates of HRA at five years justify the ongoing use of this technique in men. Female gender is an independent predictor of failure, and a higher failure rate at five years in women leads the authors to recommend this technique only in exceptional circumstances for women.

Cite this article: Bone Joint J 2013;95-B:1044–50.