Comparison of closed and open kinetic chain exercises following total knee arthroplasty in elderly women: a randomized controlled trial

This study investigated the comparative effects of a 12-week closed kinetic chain (CKC) versus open kinetic chain (OKC) exercise program on muscle strength, balance, range of motion (ROM), gait, knee function, and pain in elderly women after total knee arthroplasty (TKA). Thirty-six elderly women post-TKA were randomized into three groups: CKC exercise (n = 12), OKC exercise (n = 12), and control (n = 12). The intervention groups followed a structured 12-week exercise regimen. Outcome measures included knee flexion and extension strength, single-leg standing time, Timed Up and Go (TUG) test, six-minute walk test (6MWT), ROM, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Visual Analog Scale (VAS) scores for pain. All groups exhibited significant improvements in knee extension strength over time. The CKC group showed a 122% increase (mean difference = 10.8 Nm; 95% CI, 7.8 to 13.8; p < 0.001), outperforming the OKC (102%) and control groups (97%). ROM and static and dynamic balance improved similarly across groups without significant differences. Gait function, measured by the 6MWT, increased significantly in all groups, with the CKC group demonstrating the greatest gains. No significant differences were observed among groups for pain (VAS) and function (WOMAC) scores. Both CKC and OKC exercise programs effectively enhance lower limb strength, ROM, and balance following TKA in elderly women. However, CKC exercises confer superior benefits in knee extension strength and gait performance, suggesting their preferential use in post-TKA rehabilitation protocols.