Hip Resurfacing Associated With High Revision Rates

Joe Barber Jr., PhD

October 04, 2012

October 4, 2012 — Hip resurfacing may be associated with worse implant survival than most other surgical options for hip replacement, particularly among women, according to the findings of a retrospective study.

Alison J. Smith, MSc, from the Musculoskeletal Research Unit, School of Clinical Sciences, the University of Bristol, United Kingdom, and colleagues published their findings online October 2 in The Lancet.

The authors commented that although hip resurfacing has the potential to overcome issues associated with total hip replacement, it is associated with its own disadvantages. "[R]esurfacing does introduce new mechanisms of failure such as femoral neck fracture, and there have been initial reports of localised adverse reaction to metal (metallosis) in some patients," they write "The Australian Joint Replacement Registry reported worse outcomes in women than in men, and a very high failure rate for one brand, the Articular Surface Replacement (ASR), leading to its withdrawal."

The authors analyzed the National Joint Registry for England and Wales to identify primary total hip replacements performed between 2003 and 2011. Among the 434,560 primary total hip replacements, including 31,932 resurfacing procedures (7.4%), resurfacing was associated with higher 7-year revision rates than other surgical options, irrespective of implant head size (8.54% [95% confidence interval (CI), 7.39% - 9.85%] for 46-mm resurfacing procedure vs 3.10% [95% CI, 2.38% - 4.03%] for 36-mm uncemented ceramic prosthesis and 2.25% [95% CI, 1.71% - 2.95%] for a 28-mm uncemented metal-on-polyethylene articulation). However, the revision rates for resurfacing did decrease as the head size of the implant increased (11.67% [95% CI, 10.00% - 13.58%] for 42-mm resurfacing head size; 9.99% [95% CI, 8.71% - 11.43%] for 44-mm, and, as stated, 8.54% [95% CI, 7.39% - 9.85%] for 46-mm).

The authors eliminated ASR brand implants from the analysis. They performed a multivariate analysis with adjustments for patient age and American Society of Anesthesiologists (ASA) grade.

In total, 8.5% (95% CI, 7.8% - 9.2%) of all implants in women required revision within 5 years compared with 3.6% (95% CI, 3.3% - 3.9%) in men. Among men, resurfacing implants were not associated with 7-year revision rates significantly higher than those of other surgical options (3.37% [95% CI, 2.80% - 4.06%] for 54-mm resurfacing implant vs 2.46% [95% CI, 1.73% - 3.47%] for 40-mm uncemented ceramic implant and 4.18% [95% CI, 3.14% - 5.56%] for 28-mm uncemented metal-on-polyethylene articulation).

In multivariate analysis, head size was an independent predictor of revision for both men (hazard ratio [HR], 0.951 [95% CI, 0.945 - 0.978]; P < .0005) and women (HR, 0.921 [95% CI, 0.892 - 0.951]; P < .0005). The ASA grade was predictive of revision only in men (HR, 1.267 [95% CI, 1.042 - 1.540]; P = .018), whereas age was not predictive of revision in men or women.

The study was limited by its use of observational data and the lack of data on such confounders as pain, activity levels, and bone quality in the National Joint Registry.

The authors noted that regulatory concerns have been increased by reports of problems with breast and hip implants. "Regulators have to balance the need for innovation with the acceptability of risk," the authors write. "We need to learn the lessons from resurfacing and stemmed metal-on-metal when introducing these new technologies."

In a related commentary, Art Sedrakyan, MD, PhD, from the Patient-Centered Comparative Effectiveness Program and Medical Device Epidemiology Science and Infrastructure Center, Weill Cornell Medical College in New York City, New York, echoed the concerns of the study authors. "Regulators and surgeons need to make proper recommendations for patients, such as not using resurfacing in women, and developing decision aids for patients to convey the benefits, harms, and uncertainty related to second surgery with large metal-on-metal implants," Dr. Sedrakyan writes. "Communication with patients on all these issues should be more specific and evidence based."

The study was supported by the National Joint Registry for England and Wales. The authors and Dr. Sedrakyan have disclosed no relevant financial relationships.

Lancet. Published online October 2, 2012. Abstract