Similar Recovery Rate for Patients Aged between 50 and 89 Years That Go Home on the Surgery Day and Self-Administer Their Rehabilitation after Kinematically Aligned Total Knee Arthroplasty

Background: for kinematic alignment (KA) total knee arthroplasty (TKA), it was unknown whether ‘the pace of recovery’ at six weeks was different for patients with ages ranging between 50–59, 60–69, 70–79, and 80–89 years who were discharged on the surgery day and self-administered their rehabilitation. Methods: a single surgeon treated 206 consecutive patients with a KA-designed femoral component and an insert with a medial ball-in-socket, lateral flat articulation, and PCL retention. Each filled out preoperative and six-week Oxford Knee Score (OKS), Knee Society Score (KSS), Knee Function Score (KFS), and Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS, JR) questionnaires. The six-week minus preoperative value indicated improvement. Results: between age cohorts, the improvement was not different (p = 0.2319 to 0.9888). The mean improvement/six-week postoperative value was 6°/−2° for knee extension, 0°/119° for knee flexion, 7/31 for the OKS, 39/96 for the KSS, 7/64 for the KFS, and 13/62 for the KOOS. The 30-day hospital readmission rate was 1%. Conclusion: surgeons who perform KA TKA can counsel 50 to 89-year-old patients that they can be safely discharged home on the surgery day with a low risk of readmission and can achieve better function at six weeks than preoperatively when performing exercises without a physical therapist.