Resurfacing is comparable to total hip arthroplasty at short-term follow-up

Patients Regularly Return to Medium- and Low-Impact Types of Sporting Activities Following Distal Femoral or Proximal Tibial Replacement After Resection of a Primary Bone Sarcoma

BACKGROUND

Little is known about the resumption of sporting activities following megaprosthetic reconstruction of the distal femur and proximal tibia after resection of a bone sarcoma. Thus, the aims of our study were: (1) to assess the functional outcome; (2) to evaluate pre- and post-operatively performed sporting activities; and (3) to identify potential beneficial and limiting factors.

METHODS

Between 1993 and 2015, a total of 230 patients underwent distal femoral replacement (DFR), and 96 patients underwent proximal tibial replacement (PTR). The exclusion criteria were death, amputation, living overseas, and a congenital disability. Functional outcome and sporting activities were assessed using the Musculoskeletal Tumor Society Score (MSTS), Toronto Extremity Salvage Score (TESS), Forgotten Joint Score (FJS), subjective knee value (SKV), the Tegner activity score (TS), and the modified weighted activity score (WAS).

RESULTS

There were 93 patients who had a median follow-up of 182 months (interquartile range (IQR) 130 to 260) after DFR with the following median scores: MSTS 18 (IQR 12 to 23), TESS 75% (IQR 60 to 84), FJS 25 (IQR 8 to 40), SKV 53% (IQR 40 to 70), TS 3 (IQR 3 to 4), and WAS 4 (IQR 0 to 8). There were 42 patients who had a median follow-up of 193 months (IQR 137 to 244) after PTR had the following median scores: MSTS 17 (IQR 15 to 22), TESS 78% (IQR 68 to 88), FJS 32 (IQR 20 to 46), SKV 60% (IQR 40 to 70), TS 3 (IQR 3 to 4), and WAS 4 (IQR 1 to 10). Postoperatively, 61% of DFR and 76% of PTR patients participated in at least one sporting activity.

CONCLUSIONS

The functional outcome is overall good with a regular resumption of sporting activities. Patients' age at surgery and higher preoperative sporting levels were associated with better functional outcomes and higher postoperative sporting activity.

Function and return to sports after proximal humeral replacement in patients with primary bone sarcoma

BACKGROUND

Improved patient and limb survival rates have led to an increased interest in the functional outcome and return to sports of patients undergoing megaprosthetic reconstruction in musculoskeletal oncology. This study evaluates the functional outcome and postoperatively performed level of sports in patients undergoing proximal humeral replacement (PHR) following resection of a primary bone sarcoma and identifies potential beneficial and limiting factors.

PATIENTS AND METHODS

Between 2007 and 2020, a total of 606 patients underwent resection of a primary bone sarcoma and reconstruction with a single-design modular implant. For 112 (18%) patients, the location of the tumour was the proximal humerus. Exclusion criteria were death (n = 65), patients living overseas (n = 8), and subsequent amputation (n = 1), leaving 38 patients for evaluation, of whom 32 were available for the study (13 women, median age 42 years). Clinical data regarding oncological and surgical treatment as well as subsequent complications were obtained from the patients' electronic medical records. Functional outcome was determined using the Musculoskeletal Tumor Society Score (MSTS) and Toronto Extremity Salvage Score (TESS) as well as the Subjective Shoulder Value (SSV). Return to sports was assessed using the Tegner Activity Score (TS) and the modified Weighted Activity Score (WAS).

RESULTS

At the last follow-up after a median of 30 months (IQR 22-58), median MSTS was 18 (IQR 12-24), median TESS was 80% (IQR 69-87), median SSV was 35% (IQR 10-58), median TS was 5 (IQR 4-6) and median WAS was 5 (IQR 0-10). Preservation of the axillary nerve, a reverse shoulder reconstruction and a WAS of > 10 prior to surgery were associated with better functional outcome and return to sports activity scores.

CONCLUSION

Following PHR, good to excellent functional outcomes are possible, and patients regularly return to participate in sports activities-most commonly in low-impact types of sports, but some individuals are even able to participate in high-impact sports activities.

LEVEL OF EVIDENCE

IV.

Mid-term results of a prospective randomised controlled trial comparing large-head metal-on-metal hip replacement to hip resurfacing using patient-reported outcome measures and objective functional task-based outcomes

BACKGROUND

The early outcomes of large head-metal-on-metal total hip arthroplasty (MoM THA) are compromised by adverse local tissue reaction to metal debris. This study is the mid-term follow-up of a prospective randomised control trial (pRCT) comparing MoM THA to MoM HR. We sought to answer whether there was a difference between MoM THA and MoM HR at mid-term follow-up in the implant survival; patient-reported outcome measures (PROMs); and when performing objective functional tasks?

METHODS

A total of 104 patients were studied. Of these 56 had MoM THA (50 male) and 48 had HR (43 male). Mean age at surgery was 52 years in both groups.We reviewed this cohort at mid-term follow-up [minimum 8 years (mean 9 years; range 8-10; SD 0.7)]. PROMs that were completed were OHS, WOMAC, SF-12, and the UCLA. For objective functional task-based outcomes, gait parameters for operated legs were assessed in a subgroup of 17 patients with high UCLA.

RESULTS

Revision rate in MoM THA group was 7/56 (12.5%) and in the HR group was 1/48 (2.1%). Overall revision rate at minimum 8-year follow-up was 7.7% (8 of 104 patients). PROMs data comparing MoM THA versus HR showed no difference between the groups. 4 (8.5%) of the non-revised (47) HR patients had WOMAC function or pain score below 70. 3 (6.4%) patients had both pain and function scores <70. In the THA group, 5 (10.2%) of the non-revised (49) patients had WOMAC pain or function scores <70. 3 (6.1%) patients had both pain and function scores <70. The comparison of HA versus THA showed several gait parameters in the HR group to be better but not statistically significant (p > 0.05 Mann-Whitney U-test).

CONCLUSIONS

At mid-term follow-up, the revision rate of MoM articulation for THA is high (7.7%), being higher in large head MoM total hips versus resurfacing. Overall probability of 10-year survival is 92.3% (KM analysis, 95% for MoM THA and 98% for HR). The HR group had better functional parameters on gait-based tasks compared to THA group but this difference did not reach statistical significance.

Hip resurfacing arthroplasty and total hip arthroplasty in the same patient: which do they prefer?

INTRODUCTION

Hip resurfacing arthroplasty (HRA) is an alternative to conventional total hip arthroplasty (THA) with potential advantages of preserving femoral bone stock and the ability to participate in higher impact activities. This study compares outcomes, satisfaction and preference in patients who underwent HRA in 1 hip and THA on the contralateral side.

METHODS

62 Patients with an HRA in 1 hip and a contralateral THA were retrospectively identified at 3 centres, consisting of 38 males and 24 females with 53 patients (85.5%) undergoing HRA first. A survey regarding satisfaction and preference for each procedure and outcome scores were obtained.

RESULTS

Patients were younger (51.5 vs. 56.6 years, p = 0.002) and had longer follow-up on the HRA hip (11.0 vs. 6.0 years, p < 0.001). HRA was associated with larger increase in Harris Hip Score from preoperative to final follow-up (35.8 vs. 30.6, p = 0.035). 18 Patients (29.0%) preferred HRA, 19 (30.6%) preferred THA and 25 (40.3%) had no preference (p = 0.844). When asked what they would choose if they could only have 1 surgery again, 41 (66.1%, p < 0.001) picked HRA. Overall satisfaction (p = 0.504), willingness to live with their HRA versus THA for the rest of their life (p = 0.295) and recommendation to others (p = 0.097) were similar.

CONCLUSIONS

Although HRA is associated with risks related to metal-on-metal bearings, it showed greater increase in patient-reported outcomes and a small subjective preference amongst patients who have undergone both conventional and resurfacing arthroplasty.

What Are the Benefits of Hip Resurfacing in Appropriate Patients? A Retrospective, Propensity Score-Matched Analysis

BACKGROUND

Hip arthritis is one of the major causes of disability worldwide. Hip resurfacing arthroplasty (HRA) has emerged in recent years as an alternative to total hip arthroplasty (THA), but complications of HRA have limited the patient population to younger male patients with primary osteoarthritis and large hip anatomy. How the functional benefits of HRA in this population compare with those of THA is not entirely clear.

QUESTIONS/PURPOSES

The primary aim of this study was to determine whether there were differences in hip disability and patient satisfaction with surgery between these two groups at 2 years after surgery, using patient-reported outcome measures (PROMs) and subjective measures of patient satisfaction. Additionally, we sought to determine whether there were differences in post-operative discharge disposition, revision rates, or adverse events.

METHODS

We searched an institutional database to identify patients undergoing unilateral HRA or THA between January 2007 and July 2011 who met today's recommended criteria for HRA: younger male patients with large-enough hip anatomy to make surgery viable (a femoral head of at least 48 mm in HRA patients and, in THA patients, an acetabular shell size of 54 mm, the minimum outer shell size that could accommodate a femoral head component of 48 mm; for matching purposes, acetabular shell size in THA was used as a surrogate for the femoral head size used in HRA). We used propensity score matching to control for potentially confounding pre-operative variables and administered the Hip Disability and Osteoarthritis Outcome Score (HOOS) survey, including its subdomains, at the 2-year mark. We also assessed differences between groups in Lower Extremity Activity Scale scores, 12-item Short Form Health Survey results, and answers regarding satisfaction with surgery. We calculated minimal detectable change, minimum clinically important change, and substantial clinical benefit using anchor-based techniques for multiple outcome measures.

RESULTS

There were 251 patients in each group. HRA patients scored significantly higher than THA patients on the 2-year HOOS sports and recreation (92 versus 87, respectively) and on rates of overall satisfaction (94% versus 89%, respectively). The HRA group also had a greater chance of achieving minimum clinically important change (18.75 points) in the HOOS sports and recreation subdomains than the THA group (97% versus 91%). No significant difference was found in 6-month adverse event rates. HRA patients also had a significantly shorter mean hospital stay, a higher rate of discharge to home, and a lower incidence of a "significant" limp after surgery.

CONCLUSION

HRA may provide a functional benefit in sports and recreation and greater satisfaction in patients who meet the current criteria for HRA. Because these benefits may be small, pre-operative counseling should focus on balancing the possible functional benefits against the longer-term risks associated with metal-on-metal bearings.

Patients with hip resurfacing arthroplasty are not physically more active than those with a stemmed total hip

Background and purpose - Hip resurfacing arthroplasty (HRA) was designed for the highly active patient because of the various theoretical advantages compared with stemmed total hip arthroplasty (THA), but has shown high failure rates. Physical activity (PA) after arthroplasty is frequently determined with the use of questionnaires, which are known for their subjective nature, recall bias, and ceiling effect. These disadvantages are not applicable to physical activity monitoring (AM) using sensors. We compared objectively measured PA at long-term follow-up in a matched cohort of HRA and stemmed THA subjects.Patients and methods - We compared 2 groups of 16 patients (12 males) in each group, one having received unilateral HRA (median age 56 years at surgery) and a matched group having received unilateral stemmed THA with a small diameter femoral head (28 mm) on conventional polyethylene (median age 60 years at surgery) with osteoarthritis as indication for surgery, 10 years after surgery. Groups were matched by sex, age at surgery, and BMI. The daily habitual PA was measured over 4 consecutive days in daily living using a 3-axis accelerometer, gyroscope, and magnetometer. Both quantitative parameters (time standing, sitting, walking, number of steps, and sit-stand transfers) and qualitative parameters (walking cadence) were determined.Results - The AM was worn for a median 13 (11-16) hours per day. The median daily step count was 5,546 (2,274-9,966) for the HRA group and 4,583 (1,567-11,749) for the stemmed THA-group with 39 (21-74) versus 37 (24-62) daily sit-stand transfers respectively. The other PA parameters were also similar in both groups.Interpretation - We found similar median PA levels and also identical ranges. While short-term effects may exist, ageing and related behavioral adaptations or other effects seem to render the theoretical activity benefits from HRA irrelevant at longer follow-up.

An 18-year comparison of hybrid total hip replacement and Birmingham hip resurfacing in active young patients

AIM

To compare the long-term clinical and radiological results of metal-on-polyethylene hybrid total hip replacement (THA) with metal-on-metal Birmingham hip resurfacing (BHR) in young, active patients.

PATIENTS AND METHODS

From the 1st consecutive 63 hips in young, active patients who underwent BHR by the senior author, 54 (51 patients) were matched to patients who had undergone THA with regard to age, gender, body mass index and preoperative levels of activity. Radiologically, all hips were assessed for migration and osteolysis, THAs for polyethylene wear and BHRs for a pedestal sign. Patient-reported outcomes, mortality and revision rates were compared.

RESULTS

The mean follow-up of the patients with a hybrid THR was 19.9 years and for those with a BHR, 17.6 years. 13 patients with a hybrid THR and 5 with a BHR had died. 1 hybrid THR and 3 BHRs were lost to follow-up. The revision rate of the hybrid THRs was 14/54 and of the BHRs 6/54. Log rank comparison of Kaplan-Meier survival estimates demonstrated a significantly lower mortality in the BHR group (p = 0.039; hazard ratio [HR] = 0.37 [95% CI, 0.15-0.95]) but a non-significant difference in revision rates (p = 0.067; HR = 0.43 [95% CI, 0.18-1.06]). The BHRs recorded superior OHS (p = 0.03), UCLA (p = 0.0096), and EuroQol visual analogue scores (p = 0.03). Significantly more BHRs had run, played sport and undertaken heavy manual labour in the month preceding follow-up.

CONCLUSION

After 18 years, patients with BHRs remained more active with a lower mortality rate but demonstrated no significant difference in revision rates. Both groups demonstrated progressive radiological changes at long-term follow-up.

Patient-reported outcomes in hip resurfacing versus conventional total hip arthroplasty: a register-based matched cohort study of 726 patients

Background and purpose - The theoretical mechanical advantages of metal-on-metal hip resurfacing (MoM-HR) compared with conventional total hip arthroplasty (THA) have been questioned. Studies including measures of patient-reported function, physical activity, or health-related quality of life have been sparse. We compared patient-reported outcomes in MoM-HR patients with a matched group of patients with conventional THA at 7 years post-surgery. Patients and methods - Patients and patient data were retrieved from the Swedish Hip Arthroplasty Register. The case group, consisting of 363 patients with MoM-HR, was matched 1:1 with a control group, consisting of patients with a conventional THA. Patients were sent a postal patient-reported outcome measures (PROM) questionnaire including the Hip Disability and Osteoarthritis Outcome Score (HOOS), EQ-5D, and VAS pain. We used multivariable linear regression analyses to investigate the influence of prosthesis type. Results - 569 patients (78%) returned the questionnaire with complete responses (299 MoM-HRs and 270 conventional THAs). MoM-HR was associated with better scores in HOOS function of daily living (4 percentage units) and HOOS function in sport and recreation (8 percentage units) subscales. Type of prosthesis did not influence HOOS quality of life, HOOS pain, HOOS symptoms, EQ-5D index, hip pain, or satisfaction as measured with visual analog scales. Interpretation - At mean 7 years post-surgery, patients with hip resurfacing had somewhat better self-reported hip function than patients with conventional THA. The largest difference between groups was seen in the presumed most demanding subscale, i.e., function in sport and recreation.

Is there evidence to support an indication for surface replacement arthroplasty?: a systematic review

AIMS

Surface replacement arthroplasty (SRA), compared with traditional total hip arthroplasty (THA), is more expensive and carries unique concern related to metal ions production and hypersensitivity. Additionally, SRA is a more demanding procedure with a decreased margin for error compared with THA. To justify its use, SRA must demonstrate comparable component survival and some clinical advantages. We therefore performed a systematic literature review to investigate the differences in complication rates, patient-reported outcomes, stress shielding, and hip biomechanics between SRA and THA.

MATERIALS AND METHODS

A systematic review of the literature was completed using MEDLINE and EMBASE search engines. Inclusion criteria were level I to level III articles that reported clinical outcomes following primary SRA compared with THA. An initial search yielded 2503 potential articles for inclusion. Exclusion criteria included review articles, level IV or level V evidence, less than one year's follow-up, and previously reported data. In total, 27 articles with 4182 patients were available to analyze.

RESULTS

Fracture and infection rates were similar between SRA and THA, while dislocation rates were lower in SRA compared with THA. SRA demonstrated equivalent patient-reported outcome scores with greater activity scores and a return to high-level activities compared with THA. SRA more reliably restored native hip joint biomechanics and decreased stress shielding of the proximal femur compared with THA.

CONCLUSION

In young active men with osteoarthritis, there is evidence that SRA offers some potential advantages over THA, including: improved return to high level activities and sport, restoration of native hip biomechanics, and decreased proximal femoral stress shielding. Continued long-term follow up is required to assess ultimate survivorship of SRA.

Comparison of revision risks and complication rates between total HIP replacement and HIP resurfacing within the similar age group

BACKGROUND AND PURPOSE

Currently it is not clear whether age is a factor affecting revisions in total hip replacement (THR) and hip resurfacing (HR). This study aimed to investigate which of THR or HR has a higher risk in terms of revision and complication within similar age groups.

METHODS

A systemic review was performed for published literature research databases and local data and compared the two procedures under the condition that both groups of patients were age matched. Meta-analysis techniques were used to analyse revision and complication rates. Twenty-seven literature studies were included along with local audit data. In total, 2520 HR procedures were compared with age-matched 2526 of THR procedures.

MAIN FINDINGS

It was found that revision risk of HR is significantly higher than THR (risk ratio 1.65, 95% CI 1.28-2.31, p < 0.0001), highlighting that HR has a slightly higher chance of reoperation when compared to THR within the similar age group population. In terms of complications, HR was found to have an advantage over THR (risk ratio 0.84, 95% CI 0.73-0.96, p < 0.01).

CONCLUSION

THR had a lower revision risk but a slightly higher complication risk than HR under the condition that the two surgical procedures were applied to similar age groups of patients. In other words, age has not played an important role in revision and complication. Survivorship cannot be measured as follow-up periods were different in the studies used.

Patient Satisfaction Reporting After Total Hip Arthroplasty: A Systematic Review

This review evaluated the quality of patient satisfaction reporting after total hip arthroplasty. The initial search of the MEDLINE database yielded 755 studies. Twenty-four met the inclusion criteria. Most studies provided level III or IV evidence (n=15, 62.5%). The most common method used to assess satisfaction was the 10-point visual analog scale (7 studies, 29.2%), followed by an ordinal satisfaction scale (6 studies, 25.0%). The quality of evidence was poor, and the methods used to assess satisfaction were not standardized. Further research is needed to define the factors that affect patient satisfaction after total hip arthroplasty and how satisfaction is best measured. [Orthopedics. 2017; 40(3):e400-e404.].

Clinical and Functional Outcomes of the Birmingham Hip Resurfacing System

This study reported the outcomes of patients treated with the Birmingham Hip Resurfacing System (Smith & Nephew, Memphis, Tennessee) to identify the prevalence of complications and failures. A retrospective review of 202 patients (206 hips) was performed. Outcomes were assessed clinically with Harris Hip Score at 6 and 12 months and then yearly. Subanalysis was performed, with the hips divided according to patient sex and size of the femoral component. Mean patient age was 51±8 years, and mean follow-up was 4±1.6 years. Of the patients, 163 were men (83%) and 35 were women (17%). Postoperative improvement was significant, with preoperative Harris Hip Score of 62.9±10.6 and postoperative Harris Hip Score of 98.6±6.7 (P<.001). There were 9 patients (4%) who had complications. A total of 5 hips (2.4%) underwent revision. At 3 years, mean survival was better for men than for women (99% vs 92%, respectively). Survival was lowest in patients with femoral component diameter of less than 46 mm. According to the authors' results, the Birmingham Hip Resurfacing System resulted in good clinical outcomes at 4 years. Survival and outcomes in women, particularly those with modest bone size, are inferior.

Revision rates for metal-on-metal hip resurfacing and metal-on-metal total hip arthroplasty - a systematic review

PURPOSE

To compare revision rates of metal-on-metal (MoM) hip resurfacing (HRS) and MoM total hip arthroplasty (THA), as well as the primary causes for revisions.

METHODS

The PubMed database was queried for potentially relevant articles addressing MoMTHA and MoMHRS, a total of 51 articles were included.

RESULTS

The review includes a total number of 5,399 MoMHRS and 3,244 THA prosthesis and the reasons for prosthesis failure were divided into 7 categories and the main causes discussed. The overall MoMTHA revision rate was 4.7% after 6.9 years. MoMHRS revision rate was 5.9% after 5.7 years. The odds ratio was 1.25 (1.03:1.53) 95% CI (p = 0.03) (MoMHRS vs. MoMTHA).The studies of hip prostheses were separated into 2 categories of short- and long-term (more or less than 5 years). Short-term revision rate for MoMTHA was 4.5% after 4.8 years, and for MoMHRS 4.0% after 4.2 years. The odds ratio was 1.09 (0.82:1.43) 95% CI (0 = 0.56) (MoMTHA vs. MoMHRS). Long-term revision rate for MoMTHA was 5.2% after 7.7 years and 8.2% after 7.6 years for MoMHRS. The odds ratio was 1.58 (1.53:1.96) 95% CI (p = 0.0001) (MoMHRS vs. MoMTHA).Revision causes were divided into 7 main categories. The most common cause for revision for both MoMTHA and MoMHRS was loosening 47.6% vs. 37.7%, fracture (MoMTHA 7.69%; MoMHRS 19.62%), metal reactions (MoMTHA 7.69%; MoMHRS 26.92%) infection (MoMTHA 12.08%; MoMHRS 6.54%), instability (MoMTHA 9.13%; MoMHRS 2.69%), manufacturer defect 6.73% for MoMTHA and nonreported for MoMHRS, and miscellaneous (MoMTHA 7.69%; MoMHRS 6.54%) was stated.

INTERPRETATION

The comparison of MoMHRS and MoMTHA revision rates showed no difference in the short term, however in the longer term, the revision rate of MoMHRS was significantly higher than for MoMTHA. The linear increase in revision rate of MoMHRS may indicate a progression in failure.

Birmingham hip resurfacing in patients who are seventy years of age or older

There is no published literature to support mid to long term results of hip resurfacing (HR) arthroplasty in patients over the age of 70 years. The purpose of our study was to evaluate the function HR in this age group (70 or older at the time of surgery) at medium to long term follow-up. Between July 1997 and November 2002, the Oswestry Outcome Centre independently and prospectively collected data on 5000 Birmingham Hip Resurfacings (BHRs). 106 had been implanted in elderly patients who were 70 years of age or older. The post-operative Harris and Merle D'Aubigné and Postel (MDP) hip scores and causes for revision were used to ascertain function and implant survival. Hip scores for the older BHR patients were compared with those from younger patients. The average age at surgery of the elderly BHR cohort was 73.2 years (range, 70.0 to 87.9 years) with a mean follow-up of 7.1 years (range, 0.5 to 10.9 years). Four patients had a femoral neck fracture and required conversion to a conventional total hip replacement. There were no patients lost to follow-up and no dislocations in this series. The median Harris hip score (HHS) was significantly better in the younger BHR group compared with the elderly BHR group, (96 vs. 94 p=0.008). There was no significant difference in recovery rates after surgery. There was a significantly higher rate of revision in women than men among the elderly patients (male= 1 of 65 (1.5%); women = 3 of 19 (15.8%), p=0.03). At latest follow-up the elderly patients continued to function well when compared with the younger BHR patients. There was a high mid to long term success rate after HR in patients who were 70 years of age or older, without the failure burden possibly anticipated. Elderly patients had a poorer functional outcome, but a difference in HHS of two points may be of only minor clinical significance.

Do clinical and quality of life scores change over time after hip resurfacing?

BACKGROUND

Metal-on-metal hip resurfacing (MOMHR) is an alternative to total hip replacement in young and active patients but little is known about the evolution of clinical outcome scores of hip resurfacing over time.The purpose of this study was 1) to assess the long-term evolution of UCLA hip scores and SF-12 Quality of life evaluations in a group of patients treated with hip resurfacing arthroplasty, 2) to determine whether the age of the patient at surgery influenced these outcome measurements, and 3) whether the changes in SF-12 scores are comparable with those of the general US population.

PATIENT AND METHODS

A total of 100 patients with unilateral, unrevised, Charnley class A MOMHR were retrospectively selected for the study. UCLA and SF-12 scores were calculated preoperatively, short-term postoperatively, and beyond 10 years.

RESULTS

There was a decrease in the UCLA function and activity scores, and in the SF-12 physical scores between the short-term and the last follow-up at a minimum of 10 years. However, pain, walking, and SF-12 mental scores were maintained through the last follow-up. Furthermore, the SF-12 physical scores at last follow-up were comparable with those of the general US population while the mental scores were greater. There were no significant differences between the two age groups at any of the follow-up intervals for any outcome measurement.

CONCLUSIONS

While there is a slight decline in physical function following hip resurfacing over time, pain relief, walking ability, and quality of life are maintained.

Comparison of Acetabular Bone Resection, Offset, Leg Length and Post Operative Function Between Hip Resurfacing Arthroplasty and Total Hip Arthroplasty

Controversy exists regarding the amount of acetabular bone resection, biomechanics and function of patients receiving either total hip arthroplasty (THA) or hip resurfacing arthroplasty (HRA). A cohort of patients undergoing 36 mm ceramic-on-ceramic THA (89) or metal-on-metal HRA (86) were compared. No difference was observed when the ratio of native femoral head size was compared to the implanted acetabular component size (1.15 ± 0.1 HRA c.f. 1.13 ± 0.1 THA). No difference was observed in acetabular offset, vertical centre of rotation or function (OHS mean 47 in both groups) but leg length discrepancy (1.8 mm c.f. 5.5 mm) and femoral offset did differ (0.6 mm c.f. 4.1 mm). This demonstrates that 36 mm ceramic-on-ceramic THA is not associated with more bone resection than HRA and achieves equivalent function whilst avoiding the problems of metal-on-metal bearings.

A prospective comparative study of cementless total hip arthroplasty and hip resurfacing in patients under the age of 55 years: a ten-year follow-up

The aim of this study was to evaluate the ten-year clinical and functional outcome of hip resurfacing and to compare it with that of cementless hip arthroplasty in patients under the age of 55 years. Between 1999 and 2002, 80 patients were enrolled into the study: 24 were randomised (11 to hip resurfacing, 13 to total hip arthroplasty), 18 refused hip resurfacing and chose cementless total hip arthroplasty with a 32 mm bearing, and 38 insisted on resurfacing. The mean follow-up for all patients was 12.1 years (10 to 14). Patients were assessed clinically and radiologically at one year, five years and ten years. Outcome measures included EuroQol EQ5D, Oxford, Harris hip, University of California Los Angeles and University College Hospital functional scores. No differences were seen between the two groups in the Oxford or Harris hip scores or in the quality of life scores. Despite a similar aspiration to activity pre-operatively, a higher proportion of patients with a hip resurfacing were running and involved in sport and heavy manual labour after ten years. We found significantly higher function scores in patients who had undergone hip resurfacing than in those with a cementless hip arthroplasty at ten years. This suggests a functional advantage for hip resurfacing. There were no other attendant problems.

The Impact of Study Period on Perioperative Outcomes Following Hip Arthroplasty

We hypothesized that the time period studied would have a greater impact on perioperative outcomes than the hip arthroplasty procedure performed, demonstrating concerns with studies comparing new techniques to "historical" controls. One hundred total hip arthroplasty (THA) and 100 surface replacement arthroplasty (SRA) patients performed between 2004 and 2010 ("historical" period) were matched and compared to 50 THA and 50 SRA patients performed between 2010 and 2012 ("recent" period). Time to discharge was significantly improved for both the THA and SRA groups in the recent versus historical period by 16hours (P<0.001). At both periods, THA patients were discharged earlier by 9hours versus SRAs (P<0.0001). Study time frame had a greater impact than the operative procedure on perioperative metrics.

Comparison of Patient-Reported Outcome from Neck-Preserving, Short-Stem Arthroplasty and Resurfacing Arthroplasty in Younger Osteoarthritis Patients

Hip resurfacing has been considered a good treatment option for younger, active osteoarthritis patients. However, there are several identified issues concerning risk for neck fractures and issues related to current metal-on-metal implant designs. Neck-preserving short-stem implants have been discussed as a potential alternative, but it is yet unclear which method is better suited for younger adults. We compared hip disability and osteoarthritis outcome scores (HOOS) from a young group of patients (n = 52, age 48.9 ± 6.1 years) who had received hip resurfacing (HR) with a cohort of patients (n = 73, age 48.2 ± 6.6 years) who had received neck-preserving, short-stem implant total hip arthroplasty (THA). Additionally, durations for both types of surgery were compared. HOOS improved significantly preoperatively to last followup (>1 year) in both groups (p < 0.0001, η (2) = 0.69); there were no group effects or interactions. Surgery duration was significantly longer for resurfacing (104.4 min ± 17.8) than MiniHip surgery (62.5 min ± 14.8), U = 85.0, p < 0.0001, η (2) = 0.56. The neck-preserving short-stem approach may be preferable to resurfacing due to the less challenging surgery, similar outcome, and controversy regarding resurfacing implant designs.

Metal-on-metal hip resurfacing: correlation between clinical and radiological assessment, metal ions and ultrasound findings

PURPOSE

We report the clinical, radiological and wear analysis of 52 consecutive MoM hip resurfacings (performed on 49 younger patients) to a mean follow-up of 9.2 years.

METHODS

Every patient underwent X-ray and clinical evaluation (HHS). Ultrasonography of the hip was performed in all patients in order to identify possible cystic or solid mass in periprosthetic tissue. In case of mass >20 mm, further MRI was performed to better analyse the characteristics of lesion.

RESULTS

Five patients (five hips) had a revision. The overall survival rate was 90.38 %. The average HHS at follow-up examination was 95.5 points. No progressive radiolucent areas and no sclerosis or osteolysis around the implants were found. The US and RMI imaging showed a pseudotumour formation in two patients (correlated with high metal ion levels in blood and urine), both asymptomatic.

CONCLUSION

A significant positive correlation between inclination of the acetabular component and serum metal ion levels was found (r = 0.64 and r = 0.62 for cobalt and chromium, respectively).

Hip resurfacing versus total hip arthroplasty: a systematic review comparing standardized outcomes

BACKGROUND

Metal-on-metal hip resurfacing was developed for younger, active patients as an alternative to THA, but it remains controversial. Study heterogeneity, inconsistent outcome definitions, and unstandardized outcome measures challenge our ability to compare arthroplasty outcomes studies.

QUESTIONS/PURPOSES

We asked how early revisions or reoperations (within 5 years of surgery) and overall revisions, adverse events, and postoperative component malalignment compare among studies of metal-on-metal hip resurfacing with THA among patients with hip osteoarthritis. Secondarily, we compared the revision frequency identified in the systematic review with revisions reported in four major joint replacement registries.

METHODS

We conducted a systematic review of English language studies published after 1996. Adverse events of interest included rates of early failure, time to revision, revision, reoperation, dislocation, infection/sepsis, femoral neck fracture, mortality, and postoperative component alignment. Revision rates were compared with those from four national joint replacement registries. Results were reported as adverse event rates per 1000 person-years stratified by device market status (in use and discontinued). Comparisons between event rates of metal-on-metal hip resurfacing and THA are made using a quasilikelihood generalized linear model. We identified 7421 abstracts, screened and reviewed 384 full-text articles, and included 236. The most common study designs were prospective cohort studies (46.6%; n = 110) and retrospective studies (36%; n = 85). Few randomized controlled trials were included (7.2%; n = 17).

RESULTS

The average time to revision was 3.0 years for metal-on-metal hip resurfacing (95% CI, 2.95-3.1) versus 7.8 for THA (95% CI, 7.2-8.3). For all devices, revisions and reoperations were more frequent with metal-on-metal hip resurfacing than THA based on point estimates and CIs: 10.7 (95% CI, 10.1-11.3) versus 7.1 (95% CI, 6.7-7.6; p = 0.068), and 7.9 (95% CI, 5.4-11.3) versus 1.8 (95% CI, 1.3-2.2; p = 0.084) per 1000 person-years, respectively. This difference was consistent with three of four national joint replacement registries, but overall national joint replacement registries revision rates were lower than those reported in the literature. Dislocations were more frequent with THA than metal-on-metal hip resurfacing: 4.4 (95% CI, 4.2-4.6) versus 0.9 (95% CI, 0.6-1.2; p = 0.008) per 1000 person-years, respectively. Adverse event rates change when discontinued devices were included.

CONCLUSIONS

Revisions and reoperations are more frequent and occur earlier with metal-on-metal hip resurfacing, except when discontinued devices are removed from the analyses. Results from the literature may be misleading without consistent definitions, standardized outcome metrics, and accounting for device market status. This is important when clinicians are assessing and communicating patient risk and when selecting which device is most appropriate for individual patients.

Functional outcome following a large head total hip arthroplasty: A retrospective analysis of mid term results

BACKGROUND

One of the reasons that hip resurfacing and large head metal on metal (MOM) total hip arthroplasty (THA) became popular in Asia was the possible increased range of movement and thereby improved function of the hip joint. Due to concerns of MOM articulation an alternative bearing was sought. Hence, a shift from large head MOM to large head ceramic on ceramic (COC) was made. The aim of this study was to compare the functional outcome including range of motion (ROM) and dislocation rates following large head MOM and large head COC THA.

MATERIALS AND METHODS

Retrospectively, 39 primary THA with large head MOM with a mean age of 56 years (range 36-72 years) and average followup of 54 months (range 38-70 months) were compared with 23 primary THA with large head COC bearing with a mean age of 48 years (range 36-68 years) and an average followup of 18 months (range 12-26 months). Functional outcome was assessed using the Modified Harris Hip Score. Dislocation rate and ROM were compared.

RESULTS

Global ROM averaged 248 degrees with MOM group and 252 degrees with the COC group. One patient with metal bearing had dislocation at an average 3 year followup which required revision THA while there were no complications in the COC group. MHHS averaged 89 points in MOM and 94 in COC THR.

CONCLUSION

This study has shown that large head ceramic on ceramic THA is a good alternative to large head metal on metal THA with comparable dislocation rates and range of movements and without complications of metallosis in Asian patients.

Do young, active patients perceive advantages after surface replacement compared to cementless total hip arthroplasty?

BACKGROUND

Potential advantages suggested but not confirmed for surface replacement arthroplasty (SRA) over THA include lower frequency of limp, less thigh pain, less limb length discrepancy, and higher activity.

QUESTIONS/PURPOSES

We therefore determined whether patients having SRA had a limp, thigh pain, or limb length discrepancy less frequently or had activity levels higher than patients having THA.

METHODS

In a multicenter study, we surveyed 806 patients aged 18 to 60 years with a premorbid UCLA activity score of 6 or more who underwent hip arthroplasty for noninflammatory arthritis at one of five orthopaedic centers. Patients had either a cementless THA with an advanced bearing surface (n = 682) or an SRA (n = 124). The patients were demographically comparable. Specific telephone survey instruments were designed to assess limp, thigh pain, perception of limb length, and activity levels. Minimum followup was 1 year (mean, 2.3 years; range, 1.1-3.9 years).

RESULTS

When controlled for age, sex, and premorbid activity level, patients with SRA had a higher incidence of complete absence of any limp, lower incidence of thigh pain, lower incidence of perception of limb length discrepancy, greater ability to walk continuously for more than 60 minutes, higher percentage of patients who ran after surgery, greater distance run, and higher percentage of patients who returned to their most favored recreational activity.

CONCLUSIONS

When interviewed by an independent third party, patients with SRA reported higher levels of function with fewer symptoms and less perception of limb length discrepancy compared to a similar cohort of young, active patients with THA.

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.

The outcomes of hip resurfacing compared to standard primary total hip arthroplasty in Men

Background

The purpose of this study was to evaluate the clinical and radiographic outcomes of hip resurfacing patients and compare them to standard primary total hip arthroplasty procedures performed during the same period of time.

Methods

One hundred and fourteen consecutive men who had a mean age of 50 years (range, 20 to 85 years) and who had undergone 120 hip resurfacing arthroplasties between 2007 and 2009 were compared to 117 consecutive men (120 hips) who had undergone a standard total hip arthroplasty during the same time period. The mean follow-up was 42 months (range, 24 to 55 months) for both groups. Outcomes evaluated included implant survivorship, hip scores, activity levels, and complication rates.

Results

In the resurfacing hip arthroplasty cohort, implant survivorship was 98% with two patients requiring a revision surgery one for femoral neck fracture and another for femoral head loosening. In comparison, implant survivorship was 99% in the standard total hip arthroplasty cohort, with 1 revision due to peri-prosthetic fracture which was successfully treated with a femoral component revision. In the resurfacing and standard hip arthroplasty cohorts, the mean post-operative Harris hip scores had improved to 96 and 94 points, respectively and were statistically similar. The resurfacing cohort had achieved a significantly higher mean post-operative University of California Activity Score (6.7 versus 5 points). There were no differences in the complication rates between the two cohorts.

Conclusion

When patients meet the appropriate selection criteria in the hands of experienced and high-volume arthroplasty surgeons, hip resurfacing provides excellent results at short- to mid-term follow-up.

Minimum 5-year follow-up for primary THA using a tapered, proximally coated cementless stem

The purpose of this study was to assess the survivorship of a proximally coated, cementless femoral stem used for total hip arthroplasty at a minimum 5-year follow-up by assessing clinical outcomes and implant survival. A total of 936 primary total hip arthroplasties were performed in 854 patients by 3 high-volume surgeons between 2001 and 2007. Patients included 385 men and 469 women with a mean age of 56 years (range, 20-88 years) and a mean follow-up of 7 years (range, 5-11 years). The aseptic revision rate related to the femoral component was 0.3%. Three patients underwent revision of the femoral component. Mean postoperative Harris Hip Score improved to 91 points (range, 70-100 points). When stratified by primary cause of total hip arthroplasty, no differences were found in implant survivorship or postoperative Harris Hip Scores. With the exception of the 3 patients who underwent revision surgery, postoperative radiographic evaluation of the stems demonstrated no progressive radiolucencies, component malalignment, change in component position, or implant subsidence at most recent follow-up.These results are encouraging and indicate a 0.3% revision rate for the femoral component. The cause of primary total hip arthroplasty did not affect the clinical outcomes. These types of prostheses will provide patients with a stable implant that is expected to have excellent durability and longevity.

Survivorship, patient reported outcome and satisfaction following resurfacing and total hip arthroplasty

Resurfacing (RA) and total hip arthroplasty (THA) are options in the treatment of debilitating hip pathology. 381 patients that had undergone arthroplasty with a BHR RA, ASR RA, metal-on-metal (MoM) THA or ceramic-on-ceramic (CoC) THA were reviewed for satisfaction, function, health and survivorship at a median follow up of 50 months. Significantly lower survivorship for revision and reoperation was observed in the ASR group. The BHR and CoC demonstrated better outcome scores than the ASR (OHS and SAPS) and the BHR better scores than the MoM (OHS and SF12 PCS). In the short to medium term, survivorship and outcomes for the best performing RA (BHR) and THA (CoC) were comparable. There was a non-significant trend towards poorer outcome scores in the MoM THA group.

Short-term functional outcome after hip resurfacing surgery

Hip resurfacing arthroplasty is a popular method for treating late stage osteoarthritis, especially in young and active patients. Most studies presenting short-term follow-up after hip resurfacing present radiographic or dual clinician-patient-related outcome. These kinds of outcomes are influenced by interpretation of the clinician and do not tell us much about functional outcome from the patients perspective. Today, functional outcome is often measured using patient-reported outcome instruments. We used the patient-reported 'Hip Disability and osteoarthritis Outcome Score' questionnaire, which has good measurement properties, to assess short-term functional outcome in 160 patients (mean follow-up of 2.6 years) after hip resurfacing surgery. Furthermore, we focused on pain, range of motion, subjective improvement and complications. The majority (86.9%) of patients was free of pain after surgery and range of motion improved significantly. Subjective improvement was indicated in 95% of the patients. Mean HOOS in 149 patients was 87.5. In total, there were 11 complications (6%), and deep infections contributed the most (3.4%). In general, short-term follow-up after hip resurfacing in this cohort showed good clinical and patient-reported functional outcome. When assessing the results of medical interventions, a good PRO instrument can give reliable and valuable information from the patients perspective.

Patients report improvement in quality of life and satisfaction after hip resurfacing arthroplasty

BACKGROUND

A number of reconstructive procedures are available for the management of hip osteoarthritis. Hip resurfacing arthroplasty is now an accepted procedure, with implant survivorship comparable to THA at up to 10 years' followup in certain series. Most reports focus on implant survivorship, surgeon-derived results, or complications. Fewer data pertain to patient-reported results, including validated measures of quality of life (QoL) and satisfaction and baseline measures from which to determine magnitude of improvement. Validated patient-reported results are essential to guide patients and surgeons in the current era of informed and shared decision making.

QUESTIONS/PURPOSES

We determined whether patients reported improvement in disease-specific, joint-specific, and generic QoL after hip resurfacing arthroplasty; whether patients were satisfied with the results of the procedure; and latest activity level and return to sport.

METHODS

We retrospectively reviewed 127 patients (100 men, 27 women) who underwent 143 hip resurfacing procedures between 2002 and 2006. Mean patient age was 52 years. Patients completed the WOMAC, Oxford Hip Score, and SF-12 at baseline and again at minimum 2-year followup (mean, 2.5 years; range, 2-6 years). At latest followup, patients completed a validated satisfaction questionnaire and UCLA activity score.

RESULTS

All QoL scores improved (normalized to a 0-100 scale, where 100 = best health state). WOMAC improved from 46 to 95, Oxford Hip Score from 42 to 95, SF-12 (physical) from 34 to 54, and SF-12 (mental) from 46 to 56. Patient satisfaction score was 96. UCLA activity score was 8.

CONCLUSIONS

The majority of patients reported improvement in QoL, were very satisfied with their outcome, and returned to a high level of activity after hip resurfacing arthroplasty.

LEVEL OF EVIDENCE

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

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

BACKGROUND

A theoretical clinical advantage of hip resurfacing (HR) is the preservation of femoral bone. HR femoral component revision reportedly yields postoperative function comparable to that of primary THA. However, few studies have looked at the outcome of both HR femoral and acetabular side revisions.

QUESTIONS/PURPOSES

We determined whether (1) patients undergoing HR revision to THA have perioperative measures and outcome scores comparable to those of patients undergoing primary THA or revision of primary THA and (2) patients undergoing HR revision of both components have perioperative measures and outcome scores comparable to those of patients undergoing HR revision of the femoral component only.

METHODS

We retrospectively reviewed and compared 22 patients undergoing revision HR to a THA to a matched (age, sex, BMI) group of 23 patients undergoing primary THA and 12 patients undergoing primary THA revision. Patients completed the WOMAC and SF-12 questionnaires before surgery and at latest followup (range, 24-84 months for HR revision, 28-48 months for primary THA, and 24-48 months for revision THA). Blood loss, days in hospital, complications, and outcome scores were compared among groups.

RESULTS

We observed no differences in SF-12 scores but observed lower WOMAC stiffness, function, and total scores in the HR revision group than in the primary THA group. Patients undergoing HR revision of both components had comparable SF-12 and WOMAC stiffness, function, and total scores but overall lower WOMAC pain scores compared to patients undergoing HR revision of the femoral side only. The HR revision group had greater intraoperative blood loss compared to the primary THA group but not the revision THA group.

CONCLUSIONS

The perioperative measures and outcome scores of HR revision are comparable to those of revision THA but not primary THA. Longer followup is required to determine whether these differences persist. Patients undergoing HR revision of one or both components can expect comparable stiffness and function.

LEVEL OF EVIDENCE

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

Hip resurfacing: a systematic review of literature

PURPOSE

We conducted a systematic review of the literature in order to take stock of hip resurfacing according to the principle of "evidence based medicine". Our main objective was to compare the rate of revision of resurfacing implants with survival limits set by the National Institute of Clinical Excellence (NICE).

METHODS

A systematic review was undertaken of all published (Medline, Cochrane, EMBASE) literature research databases up to July 2012 as recommended by the PRISMA statement. Data extraction focused on functional outcomes, complications and survival rates. The survival rates of implants were analysed according to the mean of the series in comparison to the NICE criteria.

RESULTS

Fifty-three studies were identified and included 26,456 cases with an average of 499.17 ± 856.7 (range, 38-5000) cases per study. The median survival was 95.57 % ± 3.7 % (range, 84-100). The percentage of studies which satisfied the criteria set by NICE was 69.8 %. In terms of cumulative revision rates pondered by the number of implants, BHR®, Conserve Plus® and Cormet® showed the best results. The mean postoperative score was 91.2 ± 7.72 (range, 68.3-98.6). There was no statistically significant difference between implants in terms of functional outcomes.

CONCLUSION

On the basis of the current evidence base, this review of the literature emphasises the importance of certain parameters that can improve the results of resurfacing. The type of implant seems to play an important role as does patient selection.

Metal-on-Metal Bearing: Is This the End of the Line? We Do Not Think So

BACKGROUND

Recent studies have recommended the discontinuation of metal-on-metal (MoM) components in total hip arthroplasty (THA) because of adverse effects reported with large-diameter MoM THA. This is despite favorable long-term results observed with 28 and 32 mm MoM bearings.

QUESTIONS/PURPOSES

The aim of this study was to assess the value of calls for an end to MoM bearings as THA components. Specifically, we wish to address the risks associated with MoM bearings including adverse soft tissue reactions, metal ion release, and carcinogenic risk.

METHODS

The study evaluates the arguments in the literature reporting on MoM (adverse soft tissue reactions, metal ion release, and carcinogenic risk) and the experience of the current authors who re-introduced these bearings in 1995. They are balanced by a benefit-risk review of the literature and the authors' experience with MoM use.

RESULTS

Adverse reactions to metallic debris as well as metal ion release are predictable and can be prevented by adequate design (arc of coverage, clearance), metallurgy (forged instead of cast alloy, high-carbide content), and appropriate component orientation. There is no scientific evidence that carcinogenicity is increased in subjects with MoM hip prostheses. MoM articulations appear to be attractive allowing safe hip resurfacing, decreasing the risk of THA revision in active patients, and providing secure THA fixation with cement in cages in severely deformed hips. MoM bearings in women of child-bearing age are controversial, but long-term data on metallic devices in adolescents undergoing spinal surgery seem reassuring.

DISCUSSION

Adequate selection of MoM articulations ensures their safe use. These articulations are sensitive to orientation. Fifteen years of safe experience with 28- and 32-mm bearings of forged alloy and high-carbide content is the main reason for retaining them in primary and revision THA.

Low rates of heterotopic ossification after resurfacing hip arthroplasty with use of prophylactic radiotherapy in select patients

Recent reports have noted higher rates of heterotopic ossification (HO) with surface replacement arthroplasty (SRA) than with traditional total hip arthroplasty in the absence of postoperative HO prophylaxis. This study reports rates and grades of HO in 44 SRA patients with at least 1 year of follow-up. Heterotopic ossification prophylaxis was used in 32 (73%) of 44 cases. Heterotopic ossification prophylaxis consisted of radiotherapy (22/32), nonsteroidal anti-inflammatory drugs (8/32), or both (2/32). One case of clinically significant HO was documented in the no-prophylaxis group. This strategy of selective HO prophylaxis in patients felt by orthopedic surgeons to be at high risk of HO resulted in low rates of clinically relevant HO after SRA (1/44, 2.3%). Further study is needed to establish optimal selection criteria for HO prophylaxis after SRA.

Metal-on-metal hip resurfacing arthroplasty: an analysis of safety and revision rates

BACKGROUND

Metal-on-metal (MOM) hip resurfacing arthroplasty (HRA) is in clinical use as an appropriate alternative to total hip arthroplasty in young patients. In this technique, a metal cap is placed on the femoral head to cover the damaged surface of the bone and a metal cup is placed in the acetabulum.

OBJECTIVES

The primary objective of this analysis was to compare the revision rates of MOM HRA using different implants with the benchmark set by the National Institute of Clinical Excellence (NICE). The secondary objective of this analysis was to review the literature regarding adverse biological effects associated with implant material.

REVIEW METHODS

A literature search was performed on February 13, 2012, to identify studies published from January 1, 2009, to February 13, 2012.

RESULTS

The revision rates for MOM HRA using 6 different implants were reviewed. The revision rates for MOM HRA with 3 implants met the NICE criteria, i.e., a revision rate of 10% or less at 10 years. Two implants had short-term follow-ups and MOM HRA with one of the implants failed to meet the NICE criteria. Adverse tissue reactions resulting in failure of the implants have been reported by several studies. With a better understanding of the factors that influence the wear rate of the implants, adverse tissue reactions and subsequent implant failure can be minimized. Many authors have suggested that patient selection and surgical technique affect the wear rate and the risk of tissue reactions. The biological effects of high metal ion levels in the blood and urine of patients with MOM HRA implants are not known. Studies have shown an increase in chromosomal aberrations in patients with MOM articulations, but the clinical implications and long-term consequences of this increase are still unknown. Epidemiological studies have shown that patients with MOM HRA implants did not have an overall increase in mortality or risk of cancer. There is insufficient clinical data to confirm the teratogenicity of MOM implants in humans.

CONCLUSIONS

Metal-on-metal HRA can be beneficial for appropriately selected patients, provided the surgeon has the surgical skills required for performing this procedure.

Chinese experience with metal-on-metal hip resurfacing

The aim of this study was to study the actual clinical and laboratory results of metal-on-metal resurfacing hip arthroplasties by comparing with other implants. A total of 127 cases were operated on at the Department of Orthopaedics of Wuhan Union Hospital from 2005 to 2011. An important cause of failure is the fracture of the femoral neck. The chromium and cobalt levels of resurfacing hip arthroplasty and large-diameter head total hip arthroplasty (THA) are higher than those of a conventional metal-on-polyethylene total hip arthroplasty. There was a high ion level associated with an abduction angle of more than 45° and repetitive extreme hip motion in the 3 revision cases. The findings of this study are novel and quite controversial with that of the previously published literature.

Are hip resurfacing arthroplasties meeting the needs of our patients? A 2-year follow-up study

Hip resurfacing arthroplasty (HRA) is a treatment of end-stage hip arthritis in young patients with excellent bone stock. One hundred four consecutive HRAs (Depuy ASR, Warsaw, Ind) were performed with 36-Item Short Form Health Survey (SF-36), Western Ontario and McMaster University Osteoarthritis Index, Harris Hip Scores, and University of California, Los Angeles activity ratings obtained preoperatively, at 6 months, and at 1 and 2 years postoperatively. Four patients required conversion to total hip arthroplasty. All patients showed significant improvements in their activity, pain, stiffness, and function postoperatively. Patients with lower SF-36 mental component scores (MCSs) improved their MCS compared with those of the general population, as well as improving their pain and physical functioning scores. These findings demonstrate reliable improvements in standard quality of life measures in patients undergoing HRA, including those with low preoperative SF-36 MCS.

Joint perception after hip or knee replacement surgery

INTRODUCTION

Knee and hip arthroplasties are recognized as being effective. However, subjects with a prosthetic joint rarely report returned sensation comparable to their native joint.

HYPOTHESIS

Joint perception by patients following hip joint replacement is better than following knee replacement and in both cases this perception is directly related to the clinical results measured with currently validated scores.

PATIENTS AND METHODS

Patient joint perception in prosthetic reconstruction was evaluated in 347 patients, 46 who underwent unicompartmental knee arthroplasty (UKA), 119 tricompartmental knee arthroplasty (TKA), 93 hip resurfacing (HR), and 89 total hip arthroplasty (THA). The subjects' joint perception, their satisfaction, and the WOMAC clinical score were recorded and compared.

RESULTS

Joint perception was significantly worse for knee arthroplasties (TKA and UKA) compared to hip arthroplasties (THA or HR) (P<0.001). The WOMAC score was also significantly less favorable for knee arthroplasties than for hip arthroplasties (P<0.0001). However, there was no significant difference for the clinical scores between TKA and UKA as well as between HR and THA. Joint perception was strongly correlated with the WOMAC score for all groups (R(2)=0.951).

DISCUSSION

No difference was found after more conservative surgeries such as HR or UKA compared to traditional arthroplasty procedures (THA or TKA). Demonstrating inferior results in comparison to the hip, knee arthroplasties deserve particular attention and can still be improved. The assessment of joint perception used in this study can be considered a valuable clinical tool that is strongly correlated to validated, but more complex to apply, clinical scores.

Functional outcomes for 2 years comparing hip resurfacing and total hip arthroplasty

This prospective observational study of 499 patients with hip resurfacing and 255 patients with total hip arthroplasty compared outcomes for 2 years. We used propensity scores to identify matched cohorts of 118 patients with hip resurfacing and 118 patients with total hip arthroplasty. We used these cohorts to compare improvements in the Western Ontario and McMaster University (WOMAC) osteoarthritis index and Medical Outcomes Short-Form 36 physical function component (SF-36 PF) scores at 3 months and at 1 and 2 years postsurgery. Both groups demonstrated significant improvements from baseline in WOMAC and SF-36 PF. Improvements in SF-36 PF were greater for patients with hip resurfacing than for patients with total hip arthroplasty 1 and 2 years postsurgery; improvements in WOMAC were similar for both groups. The clinical significance of this observation needs further investigation.

Recovery expectations of hip resurfacing compared to total hip arthroplasty: a matched pairs study

OBJECTIVE

Expectations of higher activity levels associated with hip resurfacing arthroplasty (HRA) may be driving better outcomes in this group compared to total hip arthroplasty (THA). Previous studies evaluated patient expectations before consulting with the surgeon, although these expectations were likely unrealistic and would change after the consultation. We compared HRA and THA patient expectations after consultation with the surgeon.

METHODS

In a prospective registry setting, patients awaiting HRA were matched to THA patients by age, sex, and a preoperative Lower Extremity Activity Scale score (range 1-18, with 18 indicating levels of highest activity). Patients completed preoperatively a validated 18-item expectations survey. Mean overall expectation scores were first compared. Exploratory factor analysis (EFA) was then performed to determine if the grouping of individual expectations items represented meaningfully different underlying factors in the 2 groups.

RESULTS

We matched 123 pairs. The mean ± SD expectation scores were similar (85.2 ± 15.5 for HRA and 87.3 ± 13.9 for THA; P = 0.249). The EFA showed that HRA and THA patients shared the common expectations of pain relief and improvement in daily activities (9 items) and eliminating pain medications, the need for a cane, and improving sexual activity (3 items). THA patients perceived the remaining 6 items as an overall third expectation of participation in higher-level activities. However, HRA patients perceived a fourth expectation of normal range of motion (2 items) independent of the other higher-level activities (4 items).

CONCLUSION

Even after consulting with a surgeon, patients' expectations differed between HRA and THA patients regarding higher-level activities. More counseling for patients seeking hip arthroplasty is therefore needed.

Metal ion levels and functional results after either resurfacing hip arthroplasty or conventional metal-on-metal hip arthroplasty

BACKGROUND

Modern metal-on-metal hip resurfacing was introduced as a bone-preserving method of joint reconstruction for young and active patients; however, the large diameter of the bearing surfaces is of concern for potentially increased metal ion release.

PATIENTS AND METHODS

71 patients (< 65 years old) were randomly assigned to receive either a resurfacing (R) hip arthroplasty (n = 38) or a conventional metal-on-metal (C) hip arthroplasty (n = 33). Functional outcomes were assessed preoperatively and at 6, 12, and 24 months. Cobalt and chromium blood levels were analyzed preoperatively and at 3, 6, 12, and 24 months.

RESULTS

All functional outcome scores improved for both groups. At 12 and 24 months, the median UCLA activity score was 8 in the R patients and 7 in the C patients (p < 0.05). At 24 months, OHS was median 16 in C patients and 13 in R patients (p < 0.05). However, in spite of randomization, UCLA scores also appeared to be higher in R patients at baseline. Satisfaction was similar in both groups at 24 months. Cobalt concentrations were statistically significantly higher for R patients only at 3 and 6 months. Chromium levels remained significantly higher for R patients until 24 months. No pseudotumors were encountered in either group. One R patient was revised for early aseptic loosening and in 2 C patients a cup insert was exchanged for recurrent dislocation.

INTERPRETATION

R patients scored higher on UCLA, OHS, and satisfaction at some time points; however, as for the UCLA, preoperative levels were already in favor of R. The differences, although statistically significant, were of minor clinical importance. Chromium blood levels were statistically significantly higher for R patients at all follow-up measurements, whereas for cobalt this was only observed up to 6 months. The true value of resurfacing hip arthroplasty over conventional metal-on-metal hip arthroplasty will be determined by longer follow-up and a possible shift of balance between their respective (dis)advantages.

State of the art in hard-on-hard bearings: how did we get here and what have we achieved?

Total hip arthroplasty has shown excellent results in decreasing pain and improving function in patients with degenerative disease of the hip. Improvements in prosthetic materials, designs and implant fixation have now resulted in wear of the bearing surface being the limitation of this technology, and a number of hard-on-hard couples have been introduced to address this concern. The purpose of this article is to review the origins, development, survival rates and potential advantages and disadvantages of the following hard-on-hard bearings for total hip arthroplasty: metal-on-metal standard total hip arthroplasty; metal-on-metal hip resurfacing arthroplasty, ceramic-on-ceramic total hip arthroplasty; and ceramic-on-metal bearings. Improvements in the manufacturing of metal-on-metal bearings over the past 50 years have resulted in implants that provide low wear rates and allow for the use of large femoral heads. However, concerns remain regarding elevated serum metal ion levels, potential teratogenic effects and potentially devastating adverse local tissue reactions, whose incidence and pathogenesis remains unclear. Modern total hip resurfacing has shown excellent outcomes over 10 years in the hands of experienced surgeons. Current ceramic-on-ceramic bearings have demonstrated excellent survival with exceptionally low wear rates and virtually no local adverse effects. Concerns remain for insertional chipping, in vivo fracture and the variable incidence of squeaking. Contemporary ceramic-on-metal interfaces are in the early stages of clinical use, with little data reported to date. Hard-on-hard bearings for total hip arthroplasty have improved dramatically over the past 50 years. As bearing designs continue to improve with new and modified materials and improved manufacturing techniques, it is likely that the use of hard-on-hard bearings will continue to increase, especially in young and active patients.

Recovery in mechanical muscle strength following resurfacing vs standard total hip arthroplasty - a randomised clinical trial

OBJECTIVES

To evaluate the effect of resurfacing vs standard total hip replacement on post-surgery hip and knee muscle strength recovery in a prospective randomised controlled trial at the Department of Orthopaedics, University Hospital, Odense, Denmark.

METHODS

Forty-three patients were randomised into (A) standard total hip arthroplasty (S-THA) and (B) resurfacing total hip arthroplasty (R-THA). Pre-surgery assessment and follow-up were conducted (8, 26 and 52 wks). Maximal isometric muscle strength (Nm) and between-limb asymmetry for the knee extensors/flexors, hip adductors/abductors, hip extensors/flexors were analysed.

RESULTS

Maximal knee extensor and hip abductor strength were higher in S-THA than R-THA at 52 wks post-surgery (P ≤ 0.05) and hip extensors tended to be higher in S-THA at 52 wks (P = 0.06). All muscle groups showed substantial between-limb strength asymmetry (7-29%) with the affected side being weakest (P ≤ 0.05) and hip flexors being most affected. Asymmetry was present in half of the muscle groups at 26 wks (P ≤ 0.05), and remained present for the hip flexors and hip adductors at 52 wks (P ≤ 0.05).

CONCLUSIONS

R-THA patients showed an attenuated and delayed recovery in maximal lower limb muscle strength (in 2/6 muscle groups) compared to S-THA. Notably, the attenuated strength recovery following R-THA was most markedly manifested in the late phase (1 yr) of post-surgical recovery, and appeared to be due to the detachment of the lower half of the gluteus maximus muscle rather than implant design per se. Thus, the present data failed to support the hypothesis that R-THA would result in an enhanced strength rehabilitation compared to S-THA. Further, between-limb asymmetry remained present for hip flexors and adductors after 52 wks.

TRIAL REGISTRATION

NCT01229293.

Prevalence and clinical relevance of radiographic signs of impingement in metal-on-metal hybrid hip resurfacing

BACKGROUND

Implant-related impingement has been reported following metal-on-metal hip resurfacing, and reactive osseous patterns associated with implant-bone impingement have been identified. The purpose of this study was to determine the prevalence and clinical implications of radiographic signs of femoral neck-acetabular cup impingement following metal-on-metal hip resurfacing.

METHODS

Serial anteroposterior and lateral radiographs made five to 12.9 years postoperatively were available for ninety-one of the first 100 metal-on-metal hip resurfacing procedures (in eighty-nine patients) performed by the senior author. These radiographs were reviewed by a single independent observer, who was blinded to the clinical results. Radiographic signs of impingement were assessed and were correlated with clinical outcomes.

RESULTS

Twenty hips (in eighteen patients) had at least one of two reactive osseous signs: a solitary exostosis (six hips, 7%) and an erosive "divot-type" deformity (twenty hips, 22%). Each radiographic sign occurred predominantly at the superior aspect of the femoral neck just distal to the femoral component. None of the patients with such an impingement sign reported any symptoms or discomfort during examination of the range of hip motion. These patients had a greater mean postoperative University of California Los Angeles activity score and a greater mean range of hip motion than the patients without an impingement sign. Based on the numbers available, there was no association between component size, abduction angle and anteversion angle of the socket, femoral stem-femoral shaft angle, or femoral component-femoral neck ratio and the occurrence of repetitive impingement signs on radiographs.

CONCLUSIONS

The reactive osseous features identified in this study should facilitate the radiographic assessment of impingement in other patients following hip resurfacing arthroplasty. Longer-term follow-up is needed to determine whether radiographic signs of impingement are of prognostic consequence.

Survival of hard-on-hard bearings in total hip arthroplasty: a systematic review

BACKGROUND

Improvements in prosthetic materials, designs, and implant fixation for THA have led to bearing surface wear being the limitation of this technology. Hard-on-hard bearings promise decreased wear rates and increased survival. However, there may be different survival rates based on bearing materials, manufacturing technologies, and femoral component designs. Additionally, survival rate variability may be based on study design.

QUESTIONS/PURPOSES

We determined survival rates and study levels of evidence and quality for the following bearings: stemmed metal-on-metal THA, metal-on-metal hip resurfacing, ceramic-on-ceramic THA, and ceramic-on-metal THA.

METHODS

We performed a systematic review of the peer-reviewed literature addressing THA hard-on-hard bearings. Quality for Level I and II studies was assessed.

RESULTS

The four Level I or II second-generation stemmed metal-on-metal THA studies reported between 96% and 100% mean survival at 38 to 60 months. The two Level I hip resurfacing studies reported 94% and 98% mean survival at 56 and 33 months. The four Level I studies of ceramic-on-ceramic THA reported survival from 100% at mean 51 months to 96% at 8 years.

CONCLUSIONS

While hard-on-hard bearing survival rates have generally been variable with earlier designs, contemporary implants have demonstrated survival of 95% or greater at followup of between 3 and 10 years. Some variability in survival may be due to differences in surgical technique, component positioning, and implant designs. As bearing designs continue to improve with modified materials and manufacturing techniques, use will increase, especially in young and active patients, though concerns remain about the increased reports of adverse events after metal-on-metal bearings.

Direct anterior approach for hip resurfacing: surgical technique and complications

BACKGROUND

The direct anterior approach (DAA) for hip resurfacing arthroplasty is a technically difficult approach but theoretically reduces the soft tissue trauma to the hip because it does not require muscle detachments from the bone. Furthermore, the patient is in the supine position facilitating fluoroscopy to control component placement. However, the complications associated with the learning curve and functional outcome scores are not well defined in the literature.

QUESTIONS/PURPOSES

We therefore asked how our first 57 operations using the anterior approach and special table extension compared with that in the literature with regard to (1) complication rate; (2) functional outcome scores; (3) component placement; and (4) length of stay.

METHODS

We retrospectively reviewed 51 patients who underwent 57 hip resurfacing procedures using a DAA. There were 45 men and six women with an average age of 51 years (range, 31-63 years) and a body mass index of 28.7 kg/m(2) (range, 19.7-42.0 kg/m(2)). The minimum followup was 0.3 months (mean, 8.7 months; range, 0.3-24.9 months).

RESULTS

There were three atraumatic (5%) and one posttraumatic (1.8%) femoral neck fractures. Average HOOS scores were equal to or better than averages reported for total hip arthroplasty. Average cup inclination was 36.5° (range, 25°-48°). The average length of stay was 2.11 days (range, 1-4 days).

CONCLUSIONS

The surgical approach for anterior hip resurfacing is technically difficult but may have some clinical benefits. Surgeons interested in using the DAA for hip resurfacing should be very familiar with the DAA for total hip arthroplasty and with hip resurfacing.