Functional assessment of ceramic-on-ceramic hip resurfacing arthroplasty : improvement in gait at 12 months

A ceramic-on-ceramic hip resurfacing implant (cHRA) was developed and introduced in a Medicines and Healthcare products Regulatory Agency (MHRA)-approved clinical investigation. This study aimed to examine function and physical activity levels of patients with a cHRA implant using subjective and objective measures, both preoperatively and 12 months postoperatively.

A total of 82 unilateral cHRA patients consented to this study as part of the larger MHRA-approved clinical investigation. In addition to their patient-reported outcome measures (PROMs), self-reported measures of physical activity and gait analysis were undertaken preoperatively (median 1.7 weeks (IQR 0.6 to 4.2)) and postoperatively (median 52.1 weeks (IQR 50.0 to 53.9)). These data were then compared with data from a group of 43 age-, sex-, and BMI-matched healthy controls. Kinetics and kinematics were recorded using an instrumented treadmill and 3D motion capture. Statistical parametric mapping was used for analysis.

cHRA improved PROMs and self-reported physical activity from preoperative levels. cHRA improved top walking speed (5.75 km/hr (SD 1.04) vs 7.27 km/hr (SD 0.71)), achieved a more symmetrical ground reaction force profile (symmetry index value: 10.6% (SD 9.4) vs 0.9% (SD 2.1)), and increased hip range of motion (31.7° (SD 6.2°) vs 45.9° (SD 5.3°)) from preoperative levels. Postoperative data were not statistically distinguishable from the healthy controls in any domain.

These short-term results of cHRA appear promising, with the potential to restore a near-normal gait pattern and overall quality of life.