Hip resurfacing arthroplasty and total hip arthroplasty in the same patient: which do they prefer?

Two-Year Results of Ceramic-on-Ceramic Hip Resurfacing in an International Multicenter Cohort

BACKGROUND

Hip resurfacing arthroplasty (HRA) is a bone-conserving alternative to total hip arthroplasty. We present the 2-year clinical and radiographic follow-up of a novel ceramic-on-ceramic HRA in an international multicenter cohort.

METHODS

Patients undergoing HRA between September 2018 and January 2021 were prospectively included. Patient-reported outcome measures (PROMs) in the form of the Forgotten Joint Score, Hip Disability and Osteoarthritis Outcome Score Jr., Western Ontario and McMaster Universities Arthritis Index, Oxford Hip Score, and University of California, Los Angeles, Activity Score were collected preoperatively, and at 1 and 2 years postoperation. Serial radiographs were assessed for migration, component alignment, evidence of osteolysis or loosening, and heterotopic ossification formation.

RESULTS

The study identified 200 patients who reached a minimum 2-year follow-up (mean 3.5 years). Of these, 185 completed PROMs follow-up at 2 years. There was a significant improvement in Hip Disability and Osteoarthritis Outcome Score (P < .001) and Oxford Hip Score (P < .001) between the preoperative, 1-year, and 2-year outcomes. Patients had improved activity scores on the University of California, Los Angeles, Active Score (P < .001), with 45% reporting a return to high-impact activity at 2 years. At 1 and 2 years, the Forgotten Joint Score was not significantly different (P = .38). There was no migration, osteolysis, or loosening of any of the implants. No fractures were reported over the 2-year follow-up, with only 1 patient reporting a sciatic nerve palsy. There were 2 revisions, 1 for unexplained pain at 3 months due to acetabular component malposition and 1 at 33.5 months for acetabular implant failure.

CONCLUSIONS

The ceramic-on-ceramic resurfacing at 2 years postoperation demonstrates promising results with satisfactory outcomes in all recorded PROMs. Further long-term data are needed to support the widespread adoption of this prosthesis as an alternative to other HRA bearings.

A Pilot Experiment to Measure the Initial Mechanical Stability of the Femoral Head Implant in a Cadaveric Model of Osteonecrosis of Femoral Head Involving up to 50% of the Remaining Femoral Head

Background and Objectives: Currently, only patients with osteonecrosis of the femoral head (ONFH), who had bone defects involving 30–33.3% of the remaining femoral head, are indicated in hip resurfacing arthroplasty (HRA). In an experimental cadaver model of ONFH involving up to 50% of the remaining femoral head, the initial stability of the femoral head implant (FHI) at the interface between the implant and the remaining femoral head was measured. Materials and Methods: The ten specimens and the remaining ten served as the experimental group and the control group, respectively. We examined the degree of the displacement of the FHI, the bonding strength between the FHI and the retained bone and that at the interface between the FHI and bone cement. Results: Changes in the degree of displacement at the final phase from the initial phase were calculated as 0.089 ± 0.036 mm in the experimental group and 0.083 ± 0.056 mm in the control group. However, this difference reached no statistical significance (p = 0.7789). Overall, there was an increase in the degree of displacement due to the loading stress, with increased loading cycles in both groups. In cycles of up to 6000 times, there was a steep increase. After cycles of 8000 times, however, there was a gradual increase. Moreover, in cycles of up to 8000 times, there was an increase in the difference in the degree of displacement due to the loading stress between the two groups. After cycles of 8000 times, however, such difference remained almost unchanged. Conclusions: In conclusion, orthopedic surgeons could consider performing the HRA in patients with ONFH where the bone defects involved up to 50% of the remaining femoral head, without involving the femoral head–neck junction in the anterior and superior area of the femoral head. However, more evidence-based studies are warranted to justify our results.

The Effect of Travel Distance on Outcomes for Hip Resurfacing Arthroplasty at a High-Volume Center

Background

Patients are increasingly traveling greater distances to receive care at high-volume centers. The effect of travel distance on patient-reported outcomes after hip resurfacing arthroplasty has not been described.

Methods

Patients undergoing HRA by a single surgeon from January 2007 to April 2018 with minimum 2-year follow-up were reviewed retrospectively. Five hundred ninety-nine patients were identified and divided into 2 cohorts: home-to-hospital distance >100 miles and ≤100 miles from our institution. Preoperative and 2-year postoperative patient-reported outcome measures (PROMs) were assessed, including the modified Harris Hip Score and Hip disability and Osteoarthritis Outcome Score. The minimal clinically important difference (MCID) for each PROM was calculated using the distribution-based method. Chi-square tests were used for univariate comparison. Poisson regressions controlling for demographic variables were performed to determine the effect of travel distance on whether patients achieved the MCID. Multivariate linear regressions were used to determine association between distance and improvement in PROMs.

Results

A total of 599 patients met criteria for inclusion. There were 113 (18.9%) with a home-to-hospital distance >100 miles and 486 (81.1%) with distance ≤100 miles. Age was the only demographic factor different between these groups (mean: 1.1-year difference, P < .001). There were no significant differences in reaching the MCID on any PROM between these groups. Multivariate linear regressions revealed no associations between travel distance and improvement in PROMs.

Conclusions

Travel distance to a high-volume center did not affect 2-year patient-reported outcomes or rate of achieving the MCID in patients undergoing hip resurfacing arthroplasty.