A Comparative Cohort Study With a 20-Year Age Gap: Hip Resurfacing in Patients Aged ≤35 Years and Patients Aged ≥55 Years

Abstract

Background: This single-center retrospective cohort study aimed to evaluate and compare implant survival and patient-reported outcome measures in 2 distinct age groups separated by 20 years who underwent hip resurfacing arthroplasty (HRA).

Methods: Between 2005 and 2014, 2042 HRAs were performed by a single-surgeon, and 75 and 377 hips from patients aged ≤35 years and ≥55 years, respectively, were included in this study. Implant survival was determined for all available hips. Clinical features and patient-reported outcome measures were collected.

Results: Seven hips were revised, 4 for aseptic loosening of one or both components, one for infection, one for accelerated wear and metallosis, and one for femoral neck fracture. There was no difference in all-cause 10-year revision, with 97.1% (95% confidence interval 80.9 to 99.6) and 99.6% (95% confidence interval: 97 to 99.9) survivorship in younger and older patients, respectively (P = .246). Preoperatively, younger patients were less active than older patients on the Lower Extremity Activity Scale (LEAS) or University of California, Los Angeles, activity scale, but at follow-up, younger patients outpaced older ones.

Conclusion: Original to our study was the isolation and comparison of 2 distinct age groups. With excellent results in disparate age groups, HRA can be applied to a broad patient demographic and is suitable for those patients who want to achieve a high activity level as defined by Lower Extremity Activity Scale or University of California, Los Angeles, scores.

Keywords: Activity level; Hip resurfacing arthroplasty; Implant survival; Patient demographic.

Figure 1

Kaplan-Meier plot of 10-y all-cause revision. Revision is compared between patients aged ≤35 y and patients aged ≥55 y. Shading indicates 95% confidence intervals for each cohort. P value is survival comparison using log-rank test.

Figure 2

Box-and-whisker plots of the median (interquartile range [IQR]) preoperative and postoperative modified Harris Hip Score (mHHS) for the younger and older cohorts. Wilcoxon rank-sum tests were used to compare the 2 cohorts with no difference found between preoperative mHHS scores (P = .103). At follow-up, the younger patients had significantly lower scores (P = .0240).

Figure 3

Box-and-whisker plots of the median (interquartile range [IQR]) preoperative and postoperative Lower Extremity Activity Scale (LEAS) for the younger and older cohorts. Wilcoxon rank-sum tests were used to compare the 2 cohorts with younger patients lagging behind the older cohort preoperatively (P = .0013). However, at follow-up, the younger patients outpaced the older cohort (P = .0211).

Figure 4

Box-and-whisker plots of the median (interquartile range [IQR]) preoperative and postoperative University of California, Los Angeles, (UCLA) for the younger and older cohorts. Wilcoxon rank-sum tests were used to compare the 2 cohorts with younger patients lagging behind the older cohort preoperatively (P = .0013). However, at follow-up, the younger patients outpaced the older cohort (P = .0211).