Question:
In patients with hip disease, is hip resurfacing more effective than large-diameter head total hip arthroplasty (THA)?
Design:
Randomized (allocation concealed), blinded (patients and outcome assessors) controlled trial with 12-month follow-up.
Setting:
Maisonneuve-Rosemont Hospital in Montreal, Quebec, Canada.
Patients:
48 patients <65 years of age (mean age, 49.7 y; 60% men) with hip disease who were eligible for hip resurfacing or total hip arthroplasty participated. Exclusion criteria were disease in both hips or polyarticular disease, spinal or lower-limb disease that could influence gait or walking performance, neuromuscular disease, metal allergy, or pregnancy. 42 patients (88%) completed gait, posture, and functional outcomes evaluations.
Intervention:
Patients were allocated to hip resurfacing (n = 24) or total hip arthroplasty (n = 24). In all patients, surgery involved opening the fascia lata, splitting the gluteus maximus along the line of muscle fibers, and releasing the short external rotators from the greater trochanter. In the hip resurfacing group, the posterior capsulotomy was completed circumferentially. The gluteus maximus tendinous insertion on the femur was released in all men and, when needed, in women, to improve mobilization of the femur. The gluteus minimus was elevated from the ileum. With proper mobilization of the femur, the Durom acetabular cup (Zimmer, Warsaw, Indiana) was inserted. In the total hip arthroplasty group, standard techniques for the CLS femoral stem (Zimmer) were followed. Neck sleeve adapters and 3 different prosthetic neck-shaft angles were available to adjust leg length and femoral offset with the large-diameter head total hip arthroplasty system. Both groups followed the same postoperative care procedures.
Main outcome measures:
The primary outcome was gait speed (normal and fast walking speeds on a 10-m walkway). Secondary outcomes were postural balance (standing still with feet at shoulder width for 120 seconds) and specific functional tests including functional reach, timed up and go, hip flexor and abductor muscle strength, and step and hop tests. Patients also completed the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), 36-item Short Form Health Survey (SF-36) mental and physical subscales, Merle d'Aubigné questionnaire, and University of California at Los Angeles (UCLA) activity scores.
Main results:
The study had 90% power to detect a 0.18 m/s difference in walking speed between groups. 37 patients (77%) had osteoarthritis. Other diagnoses were developmental dysplasia of the hip, protrusio acetabuli, posttraumatic osteoarthritis, osteonecrosis of the femoral head, postseptic arthritis, and rheumatoid arthritis. All hips showed moderate to severe degeneration. The hip resurfacing and total hip arthroplasty groups did not differ in normal or fast walking speeds or postural balance at any follow-up point (TableTable). In terms of functional outcomes, the groups were not different for the timed up and go test, hop test, or hip flexor and abductor strength ratio. Patients in the hip resurfacing group had a longer functional reach (reaching with 1 arm as far as possible without lifting heels), and patients in the total hip arthroplasty group completed the step test faster (5 consecutive rises and descents from an 18-inch step using the operated leg to climb up and keeping the same leg on the step when going down) (Table). The groups were not different for WOMAC, SF-36, Merle d'Aubigné, or UCLA activity scores.
Conclusion:
In patients with hip disease, hip resurfacing and large-diameter head total hip arthroplasty produced similar functional outcomes.
There have been many claims regarding the benefits of hip resurfacing compared with total hip arthroplasty, including the potential for a more natural feel because of the minimal disturbance of the proximal part of the femur resulting in a better and faster functional outcome. The study by Lavigne et al. compared large-diameter head total hip arthroplasty with resurfacing in a randomized trial with blinding of patients and outcome assessors. Previous studies have compared resurfacing with total hip arthroplasty with use of 28-mm heads. Randomization and blinding can address key biases, and the authors must be commended for achieving a high level of blinding throughout the study (83.3%).
In this study, there was no significant functional benefit in patients undergoing resurfacing compared with those receiving large-diameter head total hip arthroplasty. One wonders whether releasing the gluteus maximus tendinous insertion in the resurfacing group will result in continued functional improvement in the second year secondary to a prolonged healing process. A further evaluation at the twenty-four month period would be interesting.
In conclusion, when deciding whether to perform a resurfacing arthroplasty in an appropriate patient, the one clear advantage of resurfacing is bone preservation on the femoral side. As long as the outcome of patients who receive resurfacing is similar or superior to patients who receive total hip arthroplasty, then there is still an argument for resurfacing arthroplasty. When function is considered, however, the proposed advantage of resurfacing is called into question by this study.