Is there a difference in mobility and inpatient physical therapy need after primary total hip and knee arthroplasty? A decade-by-decade analysis from 60 to 99 years.

INTRODUCTION: Extended inpatient rehabilitation (PT) after total hip (THA) and knee arthroplasty (TKA) has a significant impact on total care costs. As patients age, extended PT might be required following THA and TKA. This study examined the relationship between patient age, functional mobility, inpatient PT need, and discharge disposition in THA and TKA patients.
MATERIALS AND METHODS: This retrospective study included patients aged 60 + undergoing primary THA or TKA between 2018 and 2020 at an orthopedic hospital. Comparing by age-decade, 7374 (3600 THA, 3774 TKA) sexagenarians, 5350 (2367 THA, 2983 TKA) septuagenarians, 1356 (652 THA, 704 TKA) octogenarians, and 78 (52 THA, 26 TKA) nonagenarians were analyzed. We compared the number of PT sessions needed for discharge clearance and the postoperative functional mobility using the Activity Measure for Post-Acute Care (AM-PAC) tool. Statistical analyses included ANOVA with post-hoc Tukey's HSD for continuous data and Chi-squared test for categorical variables.
RESULTS: The number of PT sessions required for discharge clearance increased with age after THA (3.3 ± 1.9 sessions vs 3.8 ± 2.1 vs 5.0 ± 2.7 vs 6.2 ± 3.0; p < 0.01) and TKA (4.0 ± 2.1 vs 4.7 ± 3.1 vs 5.2 ± 2.8 vs 5.0 ± 1.6; p < 0.01). The functional mobility improvement as measured by AM-PAC was significantly lower for nonagenarians after THA (4.9 ± 2.8 vs 5.1 ± 2.8 vs 4.6 ± 3.3 vs 3.3 ± 3.9; p < 0.01) and TKA (5.0 ± 2.9 vs 4.7 ± 3.2 vs 3.9 ± 3.4 vs 3.2 ± 2.6; p < 0.01).
CONCLUSION: Patients in their eighth and ninth decade had less improvement in functional mobility during in-hospital rehabilitation and utilized more PT services. However, clinical results in the elderly are still satisfying and the data may be helpful for resource utilization planning and risk-adjustment in value-based payment models.