Total knee arthroplasty outcomes in older patients are still clinically beneficial: the impact of age on recovery and satisfaction in total knee arthroplasty patients.

INTRODUCTION Total knee arthroplasty (TKA) improves pain and function in osteoarthritis patients, but recovery varies with age. TKA patients average at 68.7 years old, but with wide variation, the impact of age on outcomes remains unclear. This study investigated the impact of age on recovery after TKA to provide guidelines for TKA in different age groups.

Methods

This retrospective study included patients who underwent TKA between 2018 to mid-2023 and had 1 year post-operative patient-reported outcome measures (PROMs) data. Patients completed the Oxford Knee Score (OKS), Forgotten Joint Score (FJS), VR-12 Mental Component Score (MCS) and Physical Component Score (PCS) pre-operative and 1 year post-operative. Patient Medical Care Satisfaction, Knee Normality Score, and Visual Analogue Scale (VAS) (0-100) were recorded 3 months and 1 year post-operative. Data were analyzed and adjusted for sex, body mass index (BMI), range of motion (ROM), implant type, surgeon volume, and joint alignment.

Results

Of the 1,723 participants (mean age 69.4 years, 50.7% males, average BMI 30 kg/m2), pre-operative PROMs were higher with age [OKS (p<0.001), FJS (p<0.001), MCS (p<0.001)]. At 3 months post-operative, older patients had lower Patient Medical Care Satisfaction (p=0.005) and Knee Normality Score (p=0.008) and higher VAS (p=0.001). At 1 year, older age was linked to lower OKS (p=0.002), PCS (p<0.001), and Patient Medical Care Satisfaction (p=0.02). After adjusting for covariates, OKS (p<0.0001), PCS (p<0.0001), and FJS (p=0.006) were statistically significant. ANCOVA modelling predicted cumulative difference in adjusted score between the youngest and oldest patients to exceed published minimal clinically important difference (MCID) thresholds for FJS and VR-12 PCS, but oldest age groups still experienced meaningful improvement in PROMs between pre- and post-operative, meeting all MCIDs.

Conclusion

Older age is linked to better pre-operative PROMs, but worse outcomes after surgery. These results highlight the relationship between age and recovery following TKA, indicating worse improvements in knee function for older patients. However, all post-operative PROMs in older age groups still met MCIDs, thus showing the substantial impact of TKAs in patients of all ages. LEVEL OF EVIDENCE Level IV retrospective study using historical controls or having more than one negative criterion.