Persistent Fear and Extended Swing Phase During Stair Descent Following Total Knee Arthroplasty: A Case Report.

Total knee arthroplasty (TKA) is widely recognized as an effective procedure for reducing pain, improving activities of daily living (ADLs), and enhancing the quality of life in elderly patients with advanced knee osteoarthritis (KOA). However, many patients continue to have trouble with stair descent after TKA, a key functional movement that significantly affects postoperative satisfaction. This report describes the case of an 80-year-old woman with bilateral KOA who underwent left TKA. Despite undergoing postoperative rehabilitation, she continued to experience functional impairments and fear while stair descending, prompting the initiation of outpatient physiotherapy. Initial evaluations (78 days post-surgery) revealed limited range of motion (ROM) in the knee joint, muscle weakness, and high levels of anxiety and fear of movement, as measured by patient-reported outcome measures (PROMs). Surface electromyography (EMG) further identified abnormal muscle activity in the semitendinosus muscle and medial head of the gastrocnemius. Outpatient physiotherapy was performed twice a week and focused on improving ROM, strengthening the quadriceps and hamstrings, performing knee ROM exercises and mobilization, and providing guidance on independent home training. At the final evaluation (118 days post-surgery), knee ROM improved, and the PROMs score demonstrated enhanced self-efficacy. However, anxiety and fear of movement persisted. In terms of muscle strength, no significant improvement was observed. Additionally, the swing phase was extended, and EMG during stair descent revealed increased muscle activity in the semitendinosus and medial head of the gastrocnemius, suggesting compensatory protective muscle activity due to residual fear of movement. In addition to physical factors, such as knee ROM and quadriceps muscle strength, psychosocial factors, such as fear, anxiety, and depression, are critical components influencing outcomes after TKA. Residual fear is believed to delay ROM improvement and contribute to protective-like muscle activity. This case highlights the importance of a comprehensive rehabilitation approach addressing both physical and psychological aspects to optimize functional recovery in TKA patients with a pronounced fear of movement.