No functional benefit of larger femoral heads and alternative bearings at 6 months following primary hip replacement.

BACKGROUND AND PURPOSE: There has been a recent trend towards the use of greater femoral head sizes in an attempt to improve function and enhance stability after primary hip replacement. This has been associated with the use of alternative bearings, theoretically to reduce wear and improve implant longevity. METHODS: We examined the influence of these variables on patient-reported outcome measures (PROMs) for a consecutive series of primary hip replacements using National Joint Registry (NJR) and PROMs-linked data. To minimize the confounding influence of implant design factors, the single most commonly used brand in England and Wales (DePuy Corail Pinnacle) was examined. Improvement in patient hip-specific outcomes (Oxford hip score, OHS), general health outcomes (Euroqol, EQ-5D), and rates of self-reported complications (bleeding, wound problems, re-admission, and reoperation) were compared for different head sizes (28-mm, 32-mm, and 36-mm) and bearings (metal-on-polyethylene (MoP), ceramic-on-polyethylene (CoP), and ceramic-on-ceramic (CoC)), adjusting for differences in case mix. RESULTS: At a mean follow-up of 7 months, improvements in OHS and EQ5D index were similar for 28-mm and 36-mm heads. A 32-mm head was associated with poorer function (OHS: 20, 99% CI: 19-21, p = 0.002; EQ5D index: 0.39, 99% CI: 0.36-0.42, p = 0.004), although these small differences may not be of clinical importance. There were no statistically significant benefits of either CoP or CoC bearings compared to a MoP bearing. Complication rates were similar within comparisons of head sizes or bearings. INTERPRETATION: In this short-term study, we did not find any functional benefits of larger head sizes or alternative bearings, after adjusting for other influences. We question their use in routine primary hip replacement given the lack of evidence of improved long-term survival in the literature.

Have cementless and resurfacing components improved the medium-term results of hip replacement for patients under 60 years of age?

BACKGROUND AND PURPOSE: The optimal hip replacement for young patients remains unknown. We compared patient-reported outcome measures (PROMs), revision risk, and implant costs over a range of hip replacements. METHODS: We included hip replacements for osteoarthritis in patients under 60 years of age performed between 2003 and 2010 using the commonest brand of cemented, cementless, hybrid, or resurfacing prosthesis (11,622 women and 13,087 men). The reference implant comprised a cemented stem with a conventional polyethylene cemented cup and a standard-sized head (28- or 32-mm). Differences in implant survival were assessed using competing-risks models, adjusted for known prognostic influences. Analysis of covariance was used to assess improvement in PROMs (Oxford hip score (OHS) and EQ5D index) in 2014 linked procedures. RESULTS: In males, PROMs and implant survival were similar across all types of implants. In females, revision was statistically significantly higher in hard-bearing and/or small-stem cementless implants (hazard ratio (HR) = 4) and resurfacings (small head sizes (< 48 mm): HR = 6; large head sizes (≥ 48 mm): HR = 5) when compared to the reference cemented implant. In component combinations with equivalent survival, women reported significantly greater improvements in OHS with hybrid implants (22, p = 0.006) and cementless implants (21, p = 0.03) (reference, 18), but similar EQ5D index. For men and women, National Health Service (NHS) costs were lowest with the reference implant and highest with a hard-bearing cementless replacement. INTERPRETATION: In young women, hybrids offer a balance of good early functional improvement and low revision risk. Fully cementless and resurfacing components are more costly and do not provide any additional benefit for younger patients.

A comparison of surgical approaches for primary hip arthroplasty: a cohort study of patient reported outcome measures (PROMs) and early revision using linked national databases.

The posterior and lateral approaches to primary hip arthroplasty were compared using national data from England and Wales. Specific component combinations of the most commonly used cemented and cementless implant brands were analysed separately. There was no significant difference between the approaches for all-cause revision risk (cemented: P = 0.726, cementless: P = 0.295) and revision for dislocation (P = 0.176, P = 0.695) at 12 months following 37,593 procedures, after adjusting for patient and surgical variables. Analysis of 3881 linked episodes found the posterior approach was associated with significantly higher improvement in function (Oxford Hip Score: 20.8 versus 18.9, P < 0.001 (cemented procedures); 21.7 versus 20.2, P = 0.008 (cementless), EQ5D index: 0.416 versus 0.383, P = 0.003; 0.431 versus 0.384, P = 0.003). The posterior approach may offer a functional benefit (albeit small clinically), without increased revision risk.

Implant Optimisation for Primary Hip Replacement in Patients over 60 Years with Osteoarthritis: A Cohort Study of Clinical Outcomes and Implant Costs Using Data from England and Wales.

BACKGROUND: Hip replacement is one of the most commonly performed surgical procedures worldwide; hundreds of implant configurations provide options for femoral head size, joint surface material and fixation method with dramatically varying costs. Robust comparative evidence to inform the choice of implant is needed. This retrospective cohort study uses linked national databases from England and Wales to determine the optimal type of replacement for patients over 60 years undergoing hip replacement for osteoarthritis. METHODS AND FINDINGS: Implants included were the commonest brand from each of the four types of replacement (cemented, cementless, hybrid and resurfacing); the reference prosthesis was the cemented hip procedure. Patient reported outcome scores (PROMs), costs and risk of repeat (revision) surgery were examined. Multivariable analyses included analysis of covariance to assess improvement in PROMs (Oxford hip score, OHS, and EQ5D index) (9159 linked episodes) and competing risks modelling of implant survival (79,775 procedures). Cost of implants and ancillary equipment were obtained from National Health Service procurement data. RESULTS: EQ5D score improvements (at 6 months) were similar for all hip replacement types. In females, revision risk was significantly higher in cementless hip prostheses (hazard ratio, HR = 2.22, p<0.001), when compared to the reference hip. Although improvement in OHS was statistically higher (22.1 versus 20.5, p<0.001) for cementless implants, this small difference is unlikely to be clinically important. In males, revision risk was significantly higher in cementless (HR = 1.95, p = 0.003) and resurfacing implants, HR = 3.46, p<0.001), with no differences in OHS. Material costs were lowest with the reference implant (cemented, range £1103 to £1524) and highest with cementless implants (£1928 to £4285). Limitations include the design of the study, which is intrinsically vulnerable to omitted variables, a paucity of long-term implant survival data (reflecting the duration of data collection), the possibility of revision under-reporting, response bias within PROMs data, and issues associated with current outcome scoring systems, which may not accurately reflect level of improvement in some patients. CONCLUSIONS: Cement fixation, using a polyethylene cup and a standard sized head offers good outcomes, with the lowest risks and at the lowest costs. The most commonly used cementless and resurfacing implants were associated with higher risk of revision and were more costly, while perceptions of improved function and longevity were unsupported.

Equity and need when waiting for total hip replacement surgery.

OBJECTIVES: To explore sociodemographic and health status factors associated with waiting times both for first outpatient appointment and for total hip replacement surgery (THR). METHODS: A survey of THR in five former English regions was conducted between September 1996 and October 1997. Every patient listed for THR was asked to fill out a questionnaire preoperatively. This questionnaire included the 12-item Oxford Hip Score (OHS) questionnaire and two questions on the length of time patients waited for an outpatient appointment and subsequently for their operation. RESULTS: From multiple logistic regression analyses, region, private vs. public sector, housing tenure and preoperative OHS were all independently associated with a waiting time for an outpatient appointment for > 3 months. Region, housing tenure and gender were also independently associated with a wait of >or= 6 months on the surgical waiting list. CONCLUSIONS: A large proportion of patients had long waiting times both for an outpatient appointment and while on a surgical waiting list. There were significant differences in waiting time according to social, geographical and health care system factors. Patients with a worse pain and disability at surgery waited longer for an outpatient appointment. The longer patient waited, the worse was their pain and disability, suggesting that patients were not prioritized by these criteria. Benefits of prioritizing should be tested.

Revision for unexplained pain following unicompartmental and total knee replacement.

BACKGROUND: Unicompartmental knee arthroplasty has been associated with consistently worse implant survival rates than total knee arthroplasty in worldwide arthroplasty registers. The rate of revision and the proportion of revisions performed for unexplained knee pain after either a unicompartmental or total knee arthroplasty were studied to assess if there is evidence to support the hypothesis that the numbers of revisions performed for unexplained knee pain differ between these two implant types. METHODS: Using data from the National Joint Registry (NJR) of England and Wales, we identified 402,714 primary knee arthroplasties (366,965 total knee arthroplasties and 35,749 unicompartmental knee arthroplasties) that were consecutively entered from April 2003 to December 2010. The status of all implants was assessed as of December 2010, at which time 6075 implants (4503 total knee implants and 1572 unicompartmental knee implants) had been revised at a maximum of eight years. Survival analysis and Cox regression analysis with adjustment of differences in age, sex, American Society of Anesthesiologists (ASA) grade, and indication for arthroplasty were performed with use of the end points of revision for any reason, revision for unexplained pain, and revision for other reasons. RESULTS: Revision for unexplained pain was more common after unicompartmental knee arthroplasty than after total knee arthroplasty (representing 23% of revisions as compared with 9% of revisions; p < 0.001). The five-year rate of revision for unexplained pain was 1.6% for the unicompartmental knee arthroplasty group and 0.2% for the total knee arthroplasty group. With use of Cox regression, the hazard ratio (HR) for unicompartmental knee arthroplasty relative to total knee arthroplasty with the end points of revision for any reason, revision for unexplained pain, and revision for all other reasons were 2.82 (95% confidence interval [CI], 2.66 to 2.99; p < 0.001), 6.76 (95% CI, 5.84 to 7.83; p < 0.001), and 2.39 (95% CI, 2.24 to 2.56; p < 0.001), respectively. The mean time from primary implantation to revision was similar for both implant types. CONCLUSIONS: While more unicompartmental knee implants than total knee implants were revised for unexplained pain, when these revisions for unexplained pain were discounted, unicompartmental knee arthroplasty still had a significantly greater risk of revision from other reasons than did total knee arthroplasty. The revision rate in isolation may not be a reliable way to compare different implant designs and should instead be considered in the context of the reason for failure.

Mortality, morbidity, and 1-year outcomes of primary elective total hip arthroplasty.

No representative data exist on the risks of adverse outcomes of total hip arthroplasty (THA) in the United Kingdom. A prospective observational study of unselected THA operations was carried out in 5 U.K. regions. Adverse outcomes were assessed from the hospital case notes and general practitioners of 1,100 randomly selected patients and from 7,151 patient-completed questionnaires 3 and 12 months after THA. Three-month mortality was 0.4% to 0.7%. Dislocation and thromboembolic complications were about 3% and 4%. Perioperative fracture, sciatic nerve palsy, aseptic loosening, and revision each had a risk of < or = 1%. At 1 year, 2.6% of patients had undergone another operation on the same hip, 11% reported moderate or severe pain in the operated hip, 23% had severe walking restriction, and 11% were dissatisfied with the operation. Patients and surgeons in the United Kingdom should have access to this information when making a decision about THA.