Abstract
Resurfacing arthroplasty of the hip enjoyed a resurgence of enthusiasm. A recent article has documented that the media played a significant role in its popularity, making claims that were not substantiated in scientific literature. Proponents of resurfacing arthroplasty state that it is bone conserving, provides greater stability, enhances range of motion, leads to a more normal gait, facilitates increased activity levels, decreases risk of dislocation, decreases the risk of leg length discrepancy and find that it is easier to insert in the face of deformity or retained hardware. The naysayers state that it is a more difficult operative procedure associated with a higher learning curve. They note that there are few patients who meet the selection criteria and there is an increased risk of fracture of the femoral neck. Finally, there is concern over metal ion toxicity and adverse tissue reaction. Furthermore, as we explore the literature, several studies have observed that resurfacing requires a bigger cup and results in a significantly higher volume of normal bone reamed from the acetabulum. Other studies note decreased range of motion with resurfacing compared with total hip arthroplasty (THA) secondary to an unfavourable head to neck ratio resulting in increased impingement. While resurfacing is purported to enhance functional outcomes, one randomized trial of 48 patients, 24 each resurfacing and large head THA, compared with 14 healthy control subjects found no difference in gait speed and postural balance evaluations, functional test, and clinical data at 3, 6 and 12 months post-operative. In another study comparing 337 resurfacings with 266 ceramic-on-ceramic THA, at 24 months there was no difference in Harris hip score, pain score or function score, but a statistically greater improved Harris hip range of motion score in THA. In a large meta-analysis study comparing 3269 hip resurfacings (3002 patients) with average follow-up of 3.9 years to 5907 cementless THA (5907 patients) with average follow-up of 8.4 years, the observed rate of femoral revision due to mechanical failure was 2.6% for resurfacing versus 1.3% for THA, yielding annualized rates of 0.67% and 0.15% respectively. An analysis of hip resurfacing data from national joint registries found that hip resurfacing demonstrates an overall increased failure rate compared with THA, except in males younger than 65 years old having a diagnosis of primary osteoarthritis and except with head diameters larger than 50 mm, which may be especially relevant as a contraindication for use of the procedure in female patients.
