Treatment of the young active patient with osteoarthritis of the hip

Careful patient selection together with optimal implant positioning may reduce but does not eliminate the risk of elevated serum cobalt and chrome levels following metal-on-metal hip resurfacing

BACKGROUND

Elevated serum chrome (sCr) and cobalt (sCo) concentrations are associated with local tissue adverse reactions to metal debris following metal-on-metal hip resurfacing (MoM-HR). Serum metal ions <2 µg/l are probably of little clinical relevance and a pragmatic "safe" threshold <5 µg/l has been suggested.The primary aim of this study was to evaluate if a careful selection of patients combined with optimal implant positioning could eliminate cases with "unsafe" serum metal ion levels. A secondary aim was to study the association between different risk factors and having Co and/or Cr levels >5 µg/l.

PATIENTS AND METHODS

This is a retrospective, single-institution cohort study of 410 consecutive patients operated on with a Birmingham Hip Resurfacing (BHR) implant between 2001 and 2014. 288 of these had a unilateral MoM-HR, pelvic and true lateral radiographs, and a related sCo and sCr sample, and were included in the final analysis. They were allocated to either a presumed "optimal group" consisting of only men aged <60 years old, with femoral head component >48 mm diameter, and with a cup positioned within Lewinnek's safe zones, or a "suboptimal group" consisting of the remaining patients. Fisher's exact test and multiple logistic regression analyses were performed.

RESULTS

In the optimal group 48% (47/97) had serum metal ions >2 µg/l and 8% (8/97) >5 µg/l compared to 61% (116/191) and 18% (34/191) in the suboptimal group, p = 0.059 and p = 0.034 respectively. Acetabular cups with an anteversion <5 degrees had the highest odds ratio, 6.5 (95% CI, 3.0-14.3), of having sCo and sCr concentrations exceeding 5 µg/l.

CONCLUSIONS

A well oriented BHR acetabular component in a presumably "optimal" patient reduces the risk of having elevated serum metal ions but does not eliminate it. Insufficient cup anteversion seems to be the strongest associated factor of elevated serum metals.

Hip resurfacing arthroplasty as an alternative to total hip arthroplasty in patients aged under 40 years

Aims

The aims of the study were to report for a cohort aged younger than 40 years: 1) indications for HRA; 2) patient-reported outcomes in terms of the modified Harris Hip Score (HHS); 3) dislocation rate; and 4) revision rate.

Methods

This retrospective analysis identified 267 hips from 224 patients who underwent an hip resurfacing arthroplasty (HRA) from a single fellowship-trained surgeon using the direct lateral approach between 2007 and 2019. Inclusion criteria was minimum two-year follow-up, and age younger than 40 years. Patients were followed using a prospectively maintained institutional database.

Results

A total of 217 hips (81%) were included for follow-up analysis at a mean of 3.8 years. Of the 23 females who underwent HRA, none were revised, and the median head size was 46 mm (compared to 50 mm for males). The most common indication for HRA was femoroacetabular impingement syndrome (n = 133), and avascular necrosis ( (n = 53). Mean postoperative HHS was 100 at two and five years. No dislocations occurred. A total of four hips (1.8%) required reoperation for resection of heterotopic ossification, removal of components for infection, and subsidence with loosening. The overall revision rate was 0.9%.

Conclusion

For younger patients with higher functional expectations and increased lifetime risk for revision, HRA is an excellent bone preserving intervention carrying low complication rates, revision rates, and excellent patient outcomes without lifetime restrictions allowing these patients to return to activity and sport. Thus, in younger male patients with end-stage hip disease and higher demands, referral to a high-volume HRA surgeon should be considered.

Metal-on-Metal Hips: Ten-Year Clinical and Radiographic Outcomes of the ADEPT Metal-on-Metal Hip Resurfacing and Modular Total Hip Arthroplasty

BACKGROUND

The aim of this study is to update the 10-year follow-up survivorship and metal ions levels of a cohort of metal-on-metal (MoM) hip resurfacing (HR) and large-diameter-head (LDH) total hip arthroplasty (THA).

METHODS

The study is a retrospective analysis of prospectively collected data that compared the outcomes of 24 MoM HR (21 patients) and 15 (11 patients) modular LHD MoM THA at >10 years follow-up. Baseline characteristics as well as intraoperative and postoperative information were collected, including complications, revisions, clinical and radiographic outcomes, and serum metal ions level (Cobalt, Chromium). Metal ion levels were compared using a two-tailed unpaired t-test and Wilcoxon signed-rank test (jamovi v2.3.3.0, Sydney, NSW, AU).

RESULTS

No significant differences were detected in gender, BMI, and ASA score between the two groups. Patients in the modular THA group were significantly older (57 years vs. 46 years; p < 0.05). The HR overall survivorship was 91.7% (22 of 24 hips) with survivorship from implant failure and/or aseptic loosening and/or metal debris related 100% of problems. The modular THA overall survivorship was 86.7% (13 of 15 hips) with survivorship from implant aseptic loosening and metal ions complications of 93.4% (14 of 15 hips). No significant difference was noted when comparing clinical outcomes. Metal ions were significantly lower in the HR group (Co 25.8 nmol/L vs. 89 nmol/L; p < 0.001-Cr 33.5 nmol/L vs. 55.2 nmol/L; p = 0.026).

CONCLUSION

Both implants reported excellent and comparable clinical outcomes at >10 years follow-up. The Adept HR reported remarkable survivorship, in line with the registry data, proving once again its reliability in young active males. The modular LDH THA, despite being discontinued, presented higher reliability and a lower failure rate when compared with similar withdrawn MoM implants. Trunnionosis did not appear to be a significant problem in this particular modular design.

Complications and mid to long term outcomes for hip resurfacing versus total hip replacement: a systematic review and meta-analysis

INTRODUCTION

The long-term results of total hip replacement (THR) are excellent; however, it has higher failure rates in young and active patients. Hip resurfacing arthroplasty (HRA) is an alternative in such patients and gaining popularity. This review was done to compare complications and outcomes between HRA and THA by assessing the latest level 1 studies comparing the two from the past 10 years.

METHOD

A systematic review and meta-analysis was conducted using three databases (PubMed, EMBASE and SCOPUS) to compare the complications between THR and HRA in medium to long term follow up. The primary outcome of interest included the complication and revision rate between the two techniques. Functional outcomes and ionic levels at follow up were also compared as secondary outcomes. Risk of bias assessment was done using the Cochrane risk of bias tool.

RESULT

The present review included 6 level 1 studies. These included 308 THR and 304 HRA. On meta-analysis, overall complications rates were significantly lower in HRA compared to the THA group with an Odds ratio (OR) of 2.17 (95% CI 1.21, 3.88; p = 0.009). No difference was seen between the two groups in terms of revision rate (OR 1.06 95% CI 0.57, 1.99; p = 0.85). Functional outcomes in both the groups were satisfactory but the Harris Hip Score was found to be significantly better in the resurfacing group (MD 2.99 95% CI - 4.01, - 1.96, p < 0.00001). There were increased cobalt and chromium ions in the resurfacing group but no detrimental effect was seen in terms of reported poisoning.

CONCLUSION

Despite similar function and revision rates, HRA was seen to have lesser associated complications and ionic levels may not be a detrimental issue. Hip resurfacing provides relative ease during revisions, especially in younger patients and it may be an alternative to THR in the younger population.

Survivorship of a Metal-on-Metal Total Hip Implant With Modular Titanium Adapter

BACKGROUND

Use of metal-on-metal (MoM) articulations in total hip arthroplasty (THA) has sharply declined due to high failure rates from metal-related complications. Although certain MoM designs have demonstrated only 46% survival, not all MoM designs have performed the same. The purpose of this study is to evaluate mid-term to long-term survival of a specific MoM implant with a modular titanium taper adapter.

METHODS

A retrospective review was performed on all patients who underwent primary THA at our center with the M²a-Magnum system (Zimmer Biomet, Warsaw, IN). Of 829 patients (956 hips) identified, 754 patients (869 hips) met inclusion criteria of signed research consent, minimum 2-year follow-up, and/or any revision surgery.

RESULTS

Mean follow-up was 11.0 years (range 2-16; ±3.5). Mean cup angle of inclination was 42.8° (range 24°-70°, ±6.3°), with 88.0% reconstructed within the 40° ± 10° safe zone. There were 64 revisions (7.36%): 7 (0.81%) septic and 57 (6.56%) aseptic. Of those, 32 (3.68%) were adverse reactions to metal debris. Kaplan-Meier survival free of revision for all causes was 88.6% at 16 years (95% confidence interval 86.8-90.4). Univariate analysis of risk factors for all-cause, aseptic, and adverse reaction to metal debris revision found no relationship with female gender, age ≥65 years, body mass index >30 kg/m², higher activity level, or inclination angle outlier.

CONCLUSION

The results of this study demonstrate a more favorable mid-term to long-term survivorship with this specific MoM implant compared to other designs. Although our institution no longer performs MoM THA, further investigation into differences in MoM implant designs is warranted.

Trends in hospitalization for pediatric hip arthroplasty: an epidemiological Nationwide study in Italy from 2001 to 2015

Background

The epidemiology of Pediatric Hip Arthroplasty (PHA) is unclear. Prevalence of PHA in Europe was reported in Scandinavian registries, but data on this procedure are not described in other countries. Therefore, it is challenging to redact a complete and valid epidemiological report on PHA in Europe. Nevertheless, national health statistics for PHA are helpful for an international audience, as different treatments are reported between countries. Moreover, sharing national statistics and correlating those to other countries’ protocols could be helpful to compare outcomes for different procedures internationally. The principal purpose is to evaluate the yearly hospital admission for PHA in Italy.

Methods

Data of this study were collected from the National Hospital Discharge Reports (SDO) reported at the Italian Ministry of Health.

Results

From 2001 to 2015, 770 PHA hospitalizations were performed in Italy, with an incidence of 0.5 procedures for every 100,000 pediatric Italian inhabitants. The average age of patients was 15.2 ± 4.6 years. The mean length of days of hospitalization was 10.9 ± 8.6 days. The majority of patients were male of 15–19 years old age group. A progressive decrease in days of hospitalizations was found during the years of the study.

Conclusions

In Europe, the incidence of hospital admission for PHA is not fully described. There is a lack of consensus on the best type of surgery to perform on young patients. Epidemiological studies are helpful to understand the national variation of a specific surgical procedure and compare them with other countries.

Hip Resurfacing vs Total Hip Arthroplasty in Patients Younger than 35 Years: A Comparison of Revision Rates and Patient-Reported Outcomes

Background

Hip resurfacing arthroplasty (HRA) and total hip arthroplasty (THA) are two treatment options for end-stage degenerative hip conditions. The objective of this single-center retrospective cohort study was to compare implant survival and patient-reported outcomes (PROs) in young patients (≤35 years) who underwent HRA or THA.

Methods

All patients aged 35 years or younger who underwent HRA or THA with a single high-volume arthroplasty surgeon between 2004 and 2015 were reviewed. The sample included 33 THAs (26 patients) and 76 HRAs (65 patients). Five-year implant survival and minimum 2-year PROs were compared between patient cohorts.

Results

Three patients in the THA group (9%) were revised within 5 years for instability (n = 1), squeaking (n = 1), or squeaking with a ceramic liner fracture (n = 1). No patients who underwent HRA were revised. The University of California, Los Angeles, activity score, modified Harris Hip score, and Hip Dysfunction and Osteoarthritis Outcome Scores for Joint Replacement increased by 74%, 64%, and 49%, respectively, among all patients. Compared to the HRA cohort, patients who underwent THA had lower preoperative and postoperative University of California, Los Angeles, activity, modified Harris Hip score, and Hip Dysfunction and Osteoarthritis Outcome Scores for Joint Replacement scores, yet there were no differences in the absolute improvements in any of the three measures between the two groups.

Conclusions

Excellent functional outcomes were seen in young patients undergoing either HRA or THA. Although young patients undergoing THA started at lower preoperative baseline and postoperative PROs than patients undergoing HRA, both groups improved by an equal amount after surgery, suggesting that both HRA and THA afford a similar degree of potential improvement in a young population.

Predictive factors affecting long-term survivorship of ASR metal-on-metal total hip arthroplasty

INTRODUCTION

We present the outcome of 154 ASR (Articular Surface Replacement) hips performed at the P.D Hinduja Hospital and Medical Research Centre in terms of revision rate, metal ion levels, and factors affecting survivorship. Further, determined the importance of serial metal ion estimation over single value with poorly functioning arthroplasties.

METHODS

A retrospective study of 154 ASR arthroplasties (136 patients) performed from April 2005 till March 2010 was conducted. Ninety-seven patients were available for final analysis. All patients were assessed for symptoms, radiographs, blood metal (chromium and cobalt), metal artefact reduction sequence (MARS), magnetic resonance imaging (MRI), and computerized tomography (CT).

RESULTS

Female gender, smaller femoral head, patients with a rising level of metal ion levels were more likely to have revision surgery. However, abnormal acetabular inclination/anteversion was not associated with the occurrence of raised metal ion levels, ARMD (adverse reaction to metal debris) or revision surgery. Patients with raised metal ion levels were more likely to have periprosthetic lucency, ARMD, and revision surgery. Median metal levels increased initially for the first three years. Still, patients who required revision surgery continued to have a metal ion rise until the point when revision surgery was performed. In contrast, patients who had a fall in metal ion levels did not require revision.

CONCLUSION

A single metal ion value is less predictive of failing arthroplasties; instead, a rising trend of metal ion levels can better delineate arthroplasties which will require revision. ASR hips whose blood ion levels fell after an initial rise and showed a declining trend did well.

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.

Despite higher revision rate, MoM large-head THA offers better clinical scores than HR: 14-year results from a randomized controlled trial involving 48 patients

BACKGROUND

The high failure rates of metal on metal (MoM) large diameter head total hip arthroplasty (LDH THA) and hip resurfacing (HR) prevented their long-term comparisons with regards to clinical outcome. Such knowledge would be important as ceramic LDH bearing is now available. With long-term follow-up, we investigated the difference in 1) patient-reported outcome measures (PROMs); 2) revision and adverse events rates, and 3) metal ion levels between MoM LDH THA and HR.

METHODS

Forty-eight patients were randomized for LDH THA (24) or HR (24) with the same MoM articulation. At a mean follow-up of 14 years, we compared between groups different PROMs, the number of revisions and adverse events, whole blood Cobalt (Co) and Chromium (Cr) ion levels, and radiographic signs of implant dysfunction.

RESULTS

LDH THA (all cases: revised and well-functioning) had significantly better WOMAC (94 versus 85, p = 0.04), and more frequently reported having no limitation (p = 0.04). LDH THA revision rate was 20.8% (5/24) versus 8.3% (2/24) for HR (p = 0.4). Mean Co and Cr ion levels were higher in LDH THA compared to the HR (Co: 3.8 μg/L vs 1.7 μg/L; p = 0.04 and Cr: 1.9 μg/L vs 1.4 μg/L, p = 0.1). On radiographic analyses, 2 LDH THAs showed signs of adverse reaction to metal debris, whereas 1 loose femoral HR component was documented.

CONCLUSION

In the long-term, MoM LDH THA had a high trunnion related revision rate but nonetheless showed better PROMs compared to HR. Provided with a well-functioning modular junction, non-MoM LDH THA would offer an appealing option.

TRIAL REGISTRATION

ClinicalTrials.gov ( NCT04516239 ), August 18, 2020. Retrospectively registered.

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.

15-year follow-up of MoM 36-mm THA: clinical, laboratory, and radiological (CT and MRI) prospective assessment

INTRODUCTION

There is limited knowledge of the long-term results of metal-on-metal total hip arthroplasty (MoM THA), particularly concerning adverse local tissue reaction (ALTR), Co/Cr ions level and revision rate. Even if MoM bearing surfaces are no longer used, long-term data could help in defining the course and best management for these patients. The purpose of this study is to investigate the clinical outcomes, describe radiological findings including CT metal artefact reduction algorithm for orthopaedic implants (O-MAR) and MRI multi acquisition variable resonance image combination (MAVRIC) in 36-mm MoM THA.

METHODS

In this long-term prospective study, 46 consecutive patients with primary MoM THA (mono- or bilateral) were enrolled between 2004 and 2005. Pinnacle acetabular cup, Summit cementless stem with 36-mm metal head and Ultamet CoCr alloy liner (Depuy Inc.) were implanted, in the same centre by the same senior surgeon. Patients were reviewed at 5-, 10- and 15-years, including Co/Cr levels and standard radiographs at every follow-up, whilst the 15-year follow-up included hip sonography, MRI MAVRIC and CT O-MAR.

RESULTS

At 15 years, the overall survival rate of the implants (both stems and cups) was 83% (30/36). Revisions were performed in 9% (4/46) because of ALTR, 2% (1/46) septic loosening and 2% periprosthetic fracture. Both Cr and Co concentration increased over time, even though remaining at low level risk at 15 years: Co from 0.11 (+/- 0.18) to 4.29 (+/- 3.26) and Cr from 0.38 (+/- 0.32) to 1.37 (+/- 1.15). Functional scores in non-revised patients showed good to excellent results in more than 90%. Engh-score correlated with time from surgery (p = 0.017) and with sonographic, CT and RM findings (p < 0.05). Concordance has been found between CT and MRI findings (sign-rank test, p = 0.241; Intraclass Correlation Coefficients 0.987); however, no specific MRI or CT lesion patterns could be recognised among symptomatic and non-symptomatic patients.

DISCUSSION

The long-term rate of ALTR after 36-mm MoM THA was comparable with previous studies; a regular follow-up for those implants is mandatory. During follow-up Co-Cr levels increased over time and radiography was a suitable screening technique; the Engh score in particular, proved to be a reliable assessment tool. CT O-MAR and MRI with MAVRIC protocols may add valuable data in clinical practice, although MRI is significantly more efficient than CT in the identification of ALTR lesions, peri-articular effusion and in the evaluation of soft tissues.

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.

Revision total hip arthroplasty for metal-on-metal failure

Metal-on-metal (MoM) arthroplasty systems became popular in the early-2000s due to presumed advantages of improved wear characteristics and superior stability. However, subsequent reports of abnormal soft-tissue reactions to MoM implants and national registry data reporting high failure rates raised concerns. Early outcomes of revision total hip arthroplasty (THA) for adverse reaction to metal debris (ARMD) were poor, leading to development of surveillance programs and a trend towards early revision surgery. Patients with MoM arthroplasties require surveillance, comprehensive history and physical examination, imaging with ultrasound or magnetic resonance imaging (MRI), and laboratory evaluation including metal ion levels. Operative strategies for revision THA vary from exchange of modular components to extensive debridement and reconstruction with revision components. Surgeons should be aware of the increased risks of dislocation and infection following revision THA for ARMD. However, there is growing evidence that early revision surgery prior to extensive soft tissue destruction results in improved outcomes and decreased re-operation rates. It is estimated that >1 million MoM articulations have been implanted, with a large proportion still in situ. It is imperative to understand the aetiology, presentation, and management strategies for these patients to optimise their clinical outcomes.

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.

Resurfacing hip arthroplasty better preserves a normal gait pattern at increasing walking speeds compared to total hip arthroplasty

Background and purpose - Gait analysis performed under increased physical demand may detect differences in gait between total (THA) versus resurfacing hip arthroplasty (RHA), which are not measured at normal walking speed. We hypothesized that patients after RHA would reach higher walking speeds and inclines compared with THA. Additionally, an RHA would enable a more natural gait when comparing the operated with the healthy contralateral hip. Patients and methods - From a randomized controlled trial comparing THA with RHA with at least 5 years' follow-up patients with a UCLA score of more than 3 points (n = 34) were included for an instrumented treadmill gait analysis. 25 patients with a unilateral implant (primary analysis-16 THA versus 9 RHA) and 9 patients with a bilateral implant (sub-analysis-n = 5 RHA + THA; n = 4 THA + THA). Spatiotemporal parameters, ground reaction forces, and range of motion were recorded at increasing walking speeds and inclines. Functional outcome scores were obtained. Results - At a normal walking speed of 1.1 m/s and at increasing inclines no differences were recorded in gait between the 2 groups with a unilateral hip implant. With increasing walking speed the RHA group reached a higher top walking speed (TWS) (adjusted difference 0.07 m/s, 95% CI -0.11 to 0.25) compared with THA. Additionally, RHA patients tolerated more weight on the operated side at TWS (155 N, CI 49-261) and as such weight-bearing approached the unaffected contralateral side. For the RHA group a "between leg difference" of 8 N (CI 3-245) was measured versus -129 N (CI -138 to -29) for THA (adjusted difference 144 N, CI 20-261). Hip flexion of the operated side at TWS was higher after RHA compared with THA (adjusted difference 8°, CI 1.7-14). Interpretation - In this study RHA patients reached a higher walking speed, and preserved a more normal weight acceptance and a greater range of hip flexion against their contralateral healthy leg as compared with patients with a THA.

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.

Adverse reaction to metal debris after small-head diameter metal-on-metal total hip arthroplasty: an increasing concern

INTRODUCTION:

Failures due to adverse reaction to metal debris (ARMD) have become an area of common focus among surgeons performing hip replacements. Several authors have reported data on the prevalence of these masses, in both symptomatic and asymptomatic patients after either large-diameter head metal-on-metal (MoM) total hip arthroplasty (THA) or hip resurfacing arthroplasty, with a large variability of rate. To our knowledge, few data are reported on the association of this lesion with the use of small-head diameter MoM.

METHODS:

15 hips that were revised for ARMD in small-head MoM THA were included in this study. We focused our attention on the difficulties of diagnosis and treatment and also on the histologic aspects of the harvested pathologic tissue.

RESULTS:

The histological examination of our cases showed a presence of lymphocytic infiltrate suggesting a delayed hypersensitivity reaction to the metal of type IV (ALVAL), but different from each other in term of the prevalence of the cellular component. Osteolysis and severe soft tissue damage were also observed. Revision resulted in remission of the lesion and successful implant.

CONCLUSIONS:

Our observation suggests that the evidence of ARMD should be considered even in case of small-head MoM arthroplasty and therefore these patients should be followed scrupulously with 2nd level diagnostic tools such as magnetic resonance imaging with metal artifact reduction sequence (MARS-MRI) and metal ion levels at least once. Further investigations are necessary to establish the real prevalence of this phenomenon in the whole population of small-head MoM THAs.

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.

Comparison of hip function and quality of life of total hip arthroplasty and resurfacing arthroplasty in the treatment of young patients with arthritis of the hip joint at 5 years

OBJECTIVE

To compare the medium-term clinical effectiveness of total hip arthroplasty and resurfacing arthroplasty.

DESIGN

Single centre, two-arm, parallel group, assessor blinded, randomised controlled trial with 1:1 treatment allocation.

SETTING

A large teaching hospital in England.

PARTICIPANTS

122 patients older than 18 years with severe arthritis of the hip joint, suitable for resurfacing arthroplasty of the hip. Patients were excluded if they were considered to be unable to adhere to trial procedures or complete questionnaires.

INTERVENTIONS

Total hip arthroplasty (replacement of entire femoral head and neck); hip resurfacing arthroplasty (replacement of the articular surface of femoral head only, femoral neck remains intact). Both procedures replaced the articular surface of the acetabulum.

OUTCOMES

The outcome measures were hip function assessed using the Oxford Hip Score (OHS) and health-related quality of life assessed using the EuroQol (EQ-5D). Patients were followed up annually for a minimum of 5 years. Outcome data were modelled using the generalised estimating equation methodology to explore temporal variations during follow-up.

RESULTS

60 patients were randomly assigned to hip resurfacing arthroplasty and 62 to total hip arthroplasty. 95 (78%) of the 122 original study participants provided data at 5 years. There was a small decrease in both hip functions and quality of life in both groups of patients each year during the 5-year follow-up period. However, there was no evidence of a significant difference between treatments group in the OHS (P=0.333) or the EQ-5D (P=0.501).

CONCLUSIONS

We previously reported no difference in outcome in the first year after surgery. The current medium-term results also show no evidence of a difference in hip function or health-related quality of life in the 5 years following a total hip arthroplasty versus resurfacing arthroplasty.

TRIAL REGISTRATION NUMBER

ISRCTN33354155. UKCRN 4093.

What should I expect from my recalled Adept Hip Resurfacing?

"My Hip Resurfacing (HR) has been recalled. What will happen to me?" This is the question of every patient who underwent an implant recall, a highly stressful event for both patients and physicians. Triggered by a 11.64% failure rate at 7 years, a recall process started for Adept HR with head diameter less than 48 mm. We report our experience in the recall process of 40 patients with the above-mentioned components. One patient underwent revision surgery due to an adverse reaction to metal debris at 5-year follow-up. None of the patients were scheduled for revision, with an estimated survival rate of 97.6% at 7 years. Implants were well positioned with an average acetabular inclination angle of 37°. Cobalt and chromium blood levels were below the safety threshold of clinical relevance. Functional scores were excellent. In the case of a well-positioned device with normal ion levels, a good performance of the implant is generally observed. Even if we experienced a very low revision rate, this may certainly get worse over time since not all possible failures are predictable, thus requiring a careful periodic follow-up.

Outcomes of the Recalled Articular Surface Replacement Metal-on-Metal Hip Implant System: A Systematic Review

BACKGROUND

The aim of this review was to synthesize the main findings of clinical studies that have evaluated outcomes of the articular surface replacement (ASR) Hip System.

METHODS

We performed a systematic literature search to identify all articles published between January 2008 and June 2015 that included ASR hip resurfacing arthroplasty (ASR HRA) or ASR total hip arthroplasty (ASR XL THA) outcomes according to the PRISMA statement.

RESULTS

A total of 56 studies were assessed. The prevalence of adverse local tissue reactions (ALTRs) and revision rates were found to be high. ALTR prevalence varied from 12.5% to 69% (mean, 33.5%). Mean revision rate for any reason at 4-year to 7-year follow-up was 13.8% (range, 5.6%-31%) for ASR HRA and 14.5% (range, 0%-37%) for ASR XL THA. Femoral head size <53 mm was found to correlate with higher blood metal ion levels. Femoral head size >44 mm was not associated with higher ALTR prevalence or revision rates in ASR XL THA. High blood metal ion levels (>7 μg/L Co, >7 μg/L Cr) were associated with higher failure rates and bearing-related complications. The role of cup positioning was found to be controversial.

CONCLUSION

ALTR prevalence and failure rates were high. High blood metal ion levels were a risk factor for ALTR and failure. Surprisingly, the role of cup positioning and large femoral head size in ASR XL THA were controversial. These findings should be considered in the clinical follow-up and risk stratification of patients with the ASR Hip System.

Are Females at Greater Risk for Revision Surgery After Hip Resurfacing Arthroplasty With the Articular Surface Replacement Prosthesis?

BACKGROUND

Female patients undergoing hip resurfacing arthroplasties may be at greater risk of revision surgery than males, but it is unclear whether this is related to sex or other factors. We focused our analysis on data from a prospective multicenter cohort study monitoring the ASR(TM) hip resurfacing arthroplasty prosthesis on the potential association of sex on patient-reported outcome measures (PROMs), metal ion levels, revision surgery, and presence of adverse local tissue reaction. As thousands of patients with the ASR(TM) prosthesis are still undergoing followup it is critical to optimize the protocol for monitoring these patients.

QUESTIONS/PURPOSES

We wished (1) to assess the associations between sex and implant survival, and adverse local tissue reaction; and (2) to report the differences between sexes in metal ion levels and patient-reported outcome measures.

METHODS

One thousand two hundred fifty-two patients (1390 hips) who underwent hip resurfacing arthroplasty with implantation of the ASR(TM) prosthesis from April 2003 to July 2010 were eligible for enrollment in a multicenter followup study of the ASR(TM) Hip Resurfacing System after the voluntary recall of this device was initiated by DePuy in 2010. Nine hundred seventy patients (1098 hips) were enrolled at a mean of 7 years after surgery, with a mean followup of 2 years (range, 1-3.5 years). Nine hundred fifty-eight patients (1084 hips) met the inclusion criteria: ability to provide informed consent, complete PROMs, and continued routine followup. A subset of patients (150 patients, 171 hips), who all were from one center, with annual metal artifact reduction sequence MRI were analyzed. Ninety-three percent of patients from this center had routine MRI performed. The EuroQoL (EQ-5D), Harris hip score (HHS), University of California Los Angeles (UCLA) activity score, VAS pain, radiographs, patient and surgery details, and blood cobalt and chromium levels were obtained. Cox regression analysis was conducted to identify factors associated with implant survival, using any revision as the end point, and presence of adverse local tissue reaction.

RESULTS

In patients who had unilateral surgery, the only variable found to be associated with revision surgery was HHS (hazard ratio [HR], 0.96; 95% CI, 0.94-0.97; p < 0.001). In patients who had bilateral surgery, only HHS (HR, 0.93; 95% CI, 0.90-0.97; p < 0.001) and cobalt level (HR, 1.02; 95% CI, 1.01-1.03; p < 0.001) were associated with risk for revision. In patients with metal artifact reduction sequence MRI, the only variable found to be associated with presence of adverse local tissue reaction was cobalt level (HR, 1.06; 95% CI, 1.02-1.10; p = 0.001). Cobalt and chromium concentrations were greater in female patients than in male patients (cobalt, median 1.89 versus median 1.12 parts per billion [ppb], p < 0.001; chromium, median 2.03 versus median 1.17 ppb, p < 0.001). Slight differences were observed between males and females in HHS (males median 96 versus females median 94, p < 0.001) and UCLA scores (median 8 versus median 6, p < 0.001); however, there was no difference between sexes for VAS pain (median 0.5 versus median 0.5, p = 0.405). Differences were identified between males and females in the distribution of EQ-5D scores, yet the medians were the same (median 1.0 versus median 1.0, p < 0.001).

CONCLUSIONS

Male and female patients who had hip resurfacing arthroplasty with implantation of the ASR(TM) prosthesis should be followed with equal vigilance as both are at similar risk of revision surgery and adverse local tissue reaction. Metal ion levels and HHS should be obtained at followup to monitor for risk of revision and as a screening tool for MRI. Further research is necessary to evaluate if these relationships persist in patients with other metal-on-metal prostheses.

LEVEL OF EVIDENCE

Level II, therapeutic study.

Hip resurfacing and pseudotumour

Metal on metal hip resurfacing has been used widely over the last ten years but there has been recent concern about destructive soft tissue reactions, which have been called pseudotumours by some authors. This has generated considerable controversy. This review explains why pseudotumours occur after resurfacing and how they can be prevented. It also supports the continued use of resurfacing in appropriate patients by appropriately trained surgeons.

Is a ceramic-on-ceramic bearing really superior to ceramic-on-polyethylene for primary total hip arthroplasty? A systematic review and meta-analysis of randomised controlled trials

INTRODUCTION

The outcomes of using a ceramic-on-ceramic (CoC) vs ceramic-on-polyethylene (CoP) bearing surface for primary total hip arthroplasty (THA) are much debated. We performed a systematic review and meta-analysis of randomised controlled trials (RCTs) to compare and evaluate the outcomes of these 2 bearing surfaces.

MATERIALS AND METHODS

Electronic databases (PubMed/Medline, CENTRAL, Embase and Web of Science) were systematically searched for RCTs investigating the association between bearing surfaces and outcomes following primary THA. Two investigators independently reviewed studies for eligibility, assessed the risk of bias, extracted and analysed the data.

RESULTS

In total, 13 RCTs including a total of 2,488 THAs were identified. The Harris Hip Score appeared to be similar between CoC and CoP THAs. The acetabular liner wear rate was lower in CoC than CoP THA, but the meta-analysis showed that the incidence of component-related noise and overall ceramic fracture in CoC group were 14.73 times and 6.02 times higher than CoP THA, respectively. There were no statistically significant differences in rates of radiolucent line formation (&gt;1 mm), osteolysis, loosening, revision with follow-up ≥ 5 years, intraoperative femoral fracture, dislocation, deep infection, deep venous thrombosis and leg length discrepancy between CoC and CoP THAs.

CONCLUSIONS

There appears to be no clear evidence favouring the use of either a CoC or CoP bearing surfaces in primary THA, further studies with high-quality and longer term follow-up to provide more evidence on this topic are still required.

Does surgical approach or prosthesis type affect hip joint loading one year after surgery?

Several approaches may be used for hip replacement surgery either in combination with conventional total hip arthroplasty (THA) or resurfacing hip arthroplasty (RHA). This study investigates the differences in hip loading during gait one year or more after surgery in three cohorts presenting different surgical procedures, more specific RHA placed using the direct lateral (RHA-DLA, n=8) and posterolateral (RHA-PLA, n=14) approach as well as THA placed using the direct anterior (THA-DAA, n=12) approach. For the DAA and control subjects, hip loading was also evaluated during stair ascent and descent to evaluate whether these motions can better discriminate between patients and controls compared to gait. Musculoskeletal modelling in OpenSim was used to calculate in vivo joint loading. Results showed that for all operated patients, regardless the surgical procedure, hip loading was decreased compared to control subjects, while no differences were found between patient groups. This indicates that THA via DAA results in similar hip loading as a RHA via DLA or PLA. Stair climbing did not result in more distinct differences in hip contact force magnitude between patients and controls, although differences in orientation were more distinct. However, patients after hip surgery did adjust their motion pattern to decrease the magnitude of loading on the hip joint compared to control subjects.

Hip resurfacing

Hip resurfacing has been proposed as an alternative to traditional total hip arthroplasty in young, active patients. Much has been learned following the introduction of metal-on-metal resurfacing devices in the 1990s. The triad of a well-designed device, implanted accurately, in the correct patient has never been more critical than with these implants.

Following Food and Drug Administration approval in 2006, we studied the safety and effectiveness of one hip resurfacing device (Birmingham Hip Resurfacing) at our hospital in a large, single-surgeon series. We report our early to mid–term results in 1333 cases followed for a mean of 4.3 years (2 to 5.7) using a prospective, observational registry. The mean patient age was 53.1 years (12 to 84); 70% were male and 91% had osteoarthritis. Complications were few, including no dislocations, no femoral component loosening, two femoral neck fractures (0.15%), one socket loosening (0.08%), three deep infections (0.23%), and three cases of metallosis (0.23%). There were no destructive pseudotumours.

Overall survivorship at up to 5.7 years was 99.2%. Aseptic survivorship in males under the age of 50 was 100%. We believe this is the largest United States series of a single surgeon using a single resurfacing system.

Cite this article: Bone Joint J 2016;98-B (1 Suppl A):10–13.

The Interchangeability of Plasma and Whole Blood Metal Ion Measurement in the Monitoring of Metal on Metal Hips

One hundred and twenty six paired samples of plasma and whole blood were measured with inductively coupled plasma mass spectrometry technique for metal ions analysis to determine a relationship between them. There was a significant difference between the mean plasma and whole blood concentrations of both cobalt (Co) and chromium (Cr) (p < 0.0001 for both Co and Cr). The mean ratio between plasma and whole blood Cr and Co was 1.56 (range: 0.39-3.85) and 1.54 (range: 0.64-18.26), respectively, but Bland and Altman analysis illustrated that this relationship was not universal throughout the range of concentrations. There was higher variability at high concentrations for both ions. We conclude that both these concentrations should not be used interchangeably and conversion factors are unreliable due to concentration dependent variability.

Impact of Total Hip Resurfacing Arthroplasty on Health-Related Quality of Life Measures: A Systematic Review and Meta-Analysis

The aim of this study was to investigate the effect of total hip resurfacing arthroplasty (RA) on general health-related quality of life (HRQOL) and disease/hip-specific measures. Original studies published after 2000, enrolling at least ten skeletally mature patients with a minimum follow-up of 6 months were considered. The standardized mean difference (SMD) was obtained with a random effects model. The cumulative patient population encompassed 1898 patients (2123 RA). Mean follow-up duration was 4 years. The physical component score (P<0.001) and mental component score (P=0.05) of SF-12, and the EuroQol-5D (P<0.0001) improved significantly. WOMAC global score and the subscales (P<0.00001) were also improved. Harris Hip Score (P<0.00001), Oxford Hip Score (P<0.001) and UCLA (P<0.00001) were markedly improved and patient satisfaction was favorable.

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.

A two-year radiostereometric follow-up of the first generation Birmingham mid head resection arthroplasty

During the first decade of the 21st century, metal-on-metal hip resurfacing became one of the main treatment options for younger, more active patients with osteoarthritis. However, as a result of the reported failure rate of both total hip replacement (THR) and resurfacing in patients with considerable loss of bone stock in the femoral head (e.g., in extensive avascular necrosis), other solutions have been sought for these patients. The short-stemmed Birmingham Mid Head Resection prosthesis (BMHR) combines a metal-on-metal articulation and a femoral neck preserving feature. In this study, radiostereometric analysis (RSA) was used to study migration of the BMHR femoral component in 13 hips. Translations and rotations were measured up to two years. Relative values showed no statistically significant migration. Absolute values demonstrated settling in occurring between zero and two months postoperatively in all directions studied. From two months to two years no significant migration occurred except for rotation around the x-axis of the femoral segment (p = 0.049). After initial settling-in, absolute values were low, indicating that there was no evidence of early migration or loosening of the components.

Return to sporting activity after Birmingham hip resurfacing arthroplasty: Mid term results

BACKGROUND

Hip resurfacing arthroplasty (HRA) is primarily indicated for young, active patients with disabling coxarthrosis who wish to remain active and return to sports after surgery. Relatively few prospective studies have assessed return to sporting activity and impact of gender and age on this.

MATERIALS AND METHODS

Seventy-nine consecutive patients treated with HRA were included. Patients were reviewed clinically and radiologically. Function was assessed using the modified University of California Los Angeles (UCLA) activity score. The Oxford, Harris and WOMAC hip scores were calculated.

RESULTS

Average age at the time of surgery was 54.9 years (range 34.5-73.6 years). Average preoperative and postoperative UCLA scores were 4 and 7.6 respectively. Patients were involved in 2 (0-4) sporting activities preoperatively and 2 (0-5) postoperatively. Preoperative and postoperative Oxford Hip Scores, Harris Hip Score and WOMAC scores were 40, 46 and 51 and 16, 94 and 3 respectively (P < 0.0001). Patients returned to sports at an average of 3 months postoperatively.

CONCLUSION

Patients were able to return to sports by 3 months and perform the same number of activities at preoperative intensity. Activity levels are maintained up to the medium term with few complications.

Empirical support for radiographic review: a follow-up study of total hip arthroplasty

Routine post surgery surveillance of total hip arthroplasty (THA) is widely recommended to identify asymptomatic failure but inclusion of an x-ray adds to service costs. Evidence is needed to support orthopaedic opinion in order to identify what should be included in surveillance. An investigation was conducted to establish whether an x-ray is needed in addition to patient reported outcome measures. One hundred and fifty-four THA had been assessed at 3 years and were reviewed again at 6 to 9 years (mid-term) when radiographic signs of deterioration commonly appear. Data were explored for associations between radiographic changes and changes in the participants' Oxford Hip Score, age, EuroQol 5-D score or comorbidities. Hierarchical multiple regression analysis showed that the number of radiographic changes could not be predicted by any of the other variables. This supports the inclusion of an x-ray in THA surveillance and suggests that the state of the THA cannot be determined by the use of patient reported outcome measures alone. This has implications for future arthroplasty surveillance.

Metal-on-metal hip surface replacement

Metal-on-metal resurfacing of the hip (MoMHR) has enjoyed a resurgence in the last decade, but is now again in question as a routine option for osteoarthritis of the hip. Proponents of hip resurfacing suggest that its survival is superior to that of conventional hip replacement (THR), and that hip resurfacing is less invasive, is easier to revise than THR, and provides superior functional outcomes. Our argument serves to illustrate that none of these proposed advantages have been realised and new and unanticipated serious complications, such as pseudotumors, have been associated with the procedure. As such, we feel that the routine use of MoMHR is not justified.

Cite this article: Bone Joint J 2014;96-B(11 Suppl A):17–21.

Ceramic on ceramic hip prostheses: a review of past and modern materials

Ceramic on ceramic hip prostheses are an increasingly popular choice for hip replacement. Modern manufacturing techniques and developments have increased the strength and reliability of ceramic materials. The alternative bearing couples such as metal-on-polyethylene and metal-on-metal are more inclined to wear and produce particulate debris. Despite reports of fractures and stripe wear, harder, more inert and more wear resistant, modern ceramic-ceramic hip replacements provide a strong alternative to traditional bearings.

Outcome of Birmingham hip resurfacing at ten years: role of routine whole blood metal ion measurements in screening for pseudotumours

PURPOSE

Emerging concern has arisen because of recent papers reporting a high prevalence of pseudotumours (PTs), even in patients with surface arthroplasties with a good clinical track record. The aim of our study was to establish the ten year survivorship of Birmingham hip resurfacing (BHR), to investigate whole blood (WB) metal ion levels and prevalence of adverse reactions to metal debris (ARMeD) and to determine the association of blood metal ion levels and symptoms with ARMeD in patients operated on with BHR at our institution.

METHODS

Between May 2001 and May 2004, 261 consecutive BHRs were implanted in 219 patients. All living, nonrevised patients underwent a systematic screening programme consisting of clinical examination, WB cobalt and chromium measurements and targeted cross-sectional imaging.

RESULTS

The ten year survival for the entire cohort was 91% (89-93%), with any revision as the endpoint. Prevalence of ARMeD was 6.9% in male and 8.8% in female patients. Symptomatic patients with elevated metal ion levels evinced highest prevalence (63%) of PTs compared with asymptomatic patients with elevated metal ion levels (42%) and symptomatic patients with nonelevated metal ions (11%).

CONCLUSIONS

Contradicting the current international guidelines, our results suggest that it seems beneficial to combine routine metal ion measurement with clinical assessment, even in patients with well-functioning BHRs. Further follow-up will reveal whether new PTs will develop in these patients and BHR survivorship in the longer term.

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.

Confronting hip resurfacing and big femoral head replacement gait analysis

Improved hip kinematics and bone preservation have been reported after resurfacing total hip replacement (THRS). On the other hand, hip kinematics with standard total hip replacement (THR) is optimized with large diameter femoral heads (BFH-THR). The purpose of this study is to evaluate the functional outcomes of THRS and BFH-THR and correlate these results to bone preservation or the large femoral heads. Thirty-one patients were included in the study. Gait speed, postural balance, proprioception and overall performance. Our results demonstrated a non-statistically significant improvement in gait, postural balance and proprioception in the THRS confronting to BFH-THR group. THRS provide identical outcomes to traditional BFH-THR. The THRS choice as bone preserving procedure in younger patients is still to be evaluated.

Implants for total hip arthroplasty

This article is a comprehensive review of the published literature on total hip replacement design. It seeks to provide a nonbiased view of the technology related to total hip implants and bearing surfaces. Implant designs and fixation methods are discussed with summaries of their respective long-term outcome studies. Fixation methods include cemented, cementless and hybrid techniques and are explained and presented with current outcome data and their respective failure modes that have promoted new technological development. The current data point toward cementless acetabular fixation as being superior to cemented fixation. As for stem fixation, there are good data to suggest that either method of fixation is acceptable in the proper setting. Also included in this article is a brief review of bearing surfaces and hip biomechanics.

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.

Analysis of needs of patients with idiopathic osteonecrosis of the femoral head: using focus group interviews

AIM

The current needs of patients with idiopathic osteonecrosis of the femoral head were analyzed for the purpose of seeking effective support programs that would maintain and improve the quality of life of the patients.

METHODS

A focus group interview method was used to collect data. Interviewees included eight patients. They were asked about their opinions and needs with respect to medicine, health care, and welfare.

RESULTS

Overall, four needs were revealed as particularly significant: information needs, decision-making in the absence of pre-established treatment, psychological support, and sufficient medical healthcare institutions.

CONCLUSION

These four needs are useful for the foundation of future support systems, whose main concerns will be: counseling support for patients with idiopathic osteonecrosis of the femoral head, currently adopted institutions, and resources that may be required in the future.

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.