Purpose of the study: The purpose of this work was to compare the subjective and functional outcomes of patients with a large diameter total hip arthroplasty (LD-THA) or hip resurfacing (HR).

Material and methods: Forty-eight persons were assessed and double blind randomised to receive either LD-THA (n=24) or HR (n=24). The clinical and radiographic assessment and gait analysis were performed preoperatively and at three, six and 12 months postoperatively. Gait analysis was performed once in a third group of healthy adults (n=14) who served as controls.

Results: The two groups were comparable preoperatively regarding demongraphic and functional characteristics. Postoperatively, the two groups with prostheses exhibited very rapid recovery with normalization of test results compared with controls within three to six months. The clinical assessment, the analysis of postural balance, gait analysis and most of the specific tests were not different between the two groups with prostheses.

Conclusion: There was no remarkable difference in subjective or objective assessments between subjects with a LD-THA or HR. This suggests that the only potential advantage of HR is the preservation of femoral bone stock. Long-term HR implant survival will determine the reality of this benefit.

Purpose: Better clinical outcome is generally reported after hip resurfacing when compared to conventional 28mmTHA. This may simply be the consequences of biased patient selection, patient perception or the advantageous use of larger diameter femoral heads in HR. The true clinical benefits of HR can only be assessed by comparison with LDH-THA in a blinded randomized study to eliminate/reduce those biases. This was the aim of the study.

Method: Charnley class A patients were randomized between HR or LDH-THA and kept blinded for one year. Clinical data, gait analysis, postural balance evaluations and functional tests were performed pre-operatively at 3, 6, 12 and 24 months postoperatively. Fourteen normal patients served as controls.

Results: Twenty-four patients were assigned to each group. There was no significant difference in WOMAC, SF-36, activity scores, and patient satisfaction. A slight advantage was observed for HR during the functional reach test (postural balance) and for LDH-THA during the step test (speed, strength and balance), all other tests showing no differences. Both groups quickly reached controls value for all tests by 3 months.

Conclusion: We have failed to demonstrate a clear difference in outcome between HR and LDH-THA. Both groups fully recovered quickly. The postulated clinical advantages of HR over 28mmTHA most likely result from using a larger head in highly motivated patients. The only clear advantage of HR over LDH-THA remains proximal femoral bone conservation, although with the excellent durability of currently used femoral stems, HR has to demonstrate comparable survivorship before bone conservation is considered a true benefit.

Introduction: Better clinical outcome is generally reported after hip resurfacing when compared to conventional 28mmTHA. This may simply be the consequences of biased patient selection, patient perception or the advantageous use of larger diameter femoral heads in HR. The true clinical benefits of HR can only be assessed by comparison with LDH-THA in a blinded randomized study to eliminate/reduce those biases. This was the aim of the study.

Materials and Methods: Charnley class A patients were randomized between HR or LDH-THA and kept blinded for one year. Clinical data, gait analysis, postural balance evaluations and functional tests were performed preoperatively, at 3, 6, 12 and 24 months postoperatively. 14 normal patients served as controls.

Results: 24 patients were assigned to each group. There was no significant difference in WOMAC, SF-36, activity scores, and patient satisfaction. A slight advantage was observed for HR during the functional reach test (postural balance) and for LDH-THA during the step test (speed, strength and balance), all other tests showing no differences. Both groups quickly reached controls value for all tests by 3 months.

Discussion: We have failed to demonstrate a clear difference in outcome between HR and LDH-THA. Both groups fully recovered quickly. The postulated clinical advantages of HR over 28mmTHA most likely result from using a larger head in highly motivated patients. The only clear advantage of HR over LDH-THA remains proximal femoral bone conservation, although with the excellent durability of currently used femoral stems, HR has to demonstrate comparable survivorship before bone conservation is considered a true benefit.

Purpose: Kinematic studies have shown that patients with a total hip arthroplasty (THA) walk with different gait characteristics compared to normal subjects. This abnormal gait might result from difficulties restoring the normal hip anatomy and biomechanics with THA. Surface replacement arthroplasty (SRA) facilitates leg length management and reconstruction of the normal anatomy of the proximal femur, allowing potential improvements in muscle power, proprioception and hip stability compared to THA.

Method: Patients suffering from advanced hip joint disease were randomised to receive an uncemented metal-metal THA or metal-metal SRA. A group of patients from this study were evaluated pre operatively, at 6 months and one year post operatively at a gait laboratory. A VICON system with 8 cameras, platform (AMTI) and surface electromyograph (Motion Lab) were used. Articular and muscle power and work characteristics of the hip, knee and ankle were analysed with different tasks. Postural stability (e.g. distance between the mass centre and pressure centre) in the standing position will serve to differentiate the 2 groups. Other specific tests, such as the hop test, the step test and the TUG test, were performed.

Summary of Results: Thirty randomised patients were evaluated. The results will be presented and discussed.

Discussion: Considering the strong interest of patients and surgeons for the potential functional benefits of surface replacement arthroplasty, it is necessary to determine scientifically how it compares with the standard of care (THA). Patient age, weight, sex and pre operative function have a strong influence on the post operative function. Thus, a prospective randomised study is mandatory to obtain valid results.

Significance: We strongly believe that this subject warrants special attention considering the possible benefits associated with this technique in the young adult with hip osteoarthitis.