Proprioception and balance control in ankle osteoarthritis and after total ankle replacement: a prospective assessment

Purpose: Ankle proprioception is one of the most important components contributing to balance control during walking and sports activities. The information from ankle receptors and central processing is essential for postural and balance control1. Due to aging, both static position sense and movement detection threshold appear to deteriorate. In older adults, this impaired proprioception could result in balance problems, a higher incidence of falls, and a compromised quality of life. Total Ankle Replacement (TAR) could, in theory, partially restore joint sensation and motion, enhancing motor coordination, functional stability, and proprioception in a joint affected by osteoarthritis. This study aims to evaluate ankle proprioception before and after TAR through instrumental objective assessment. Methods: Thirty-four patients with degenerative ankle arthropathy and candidates for anterior TAR were evaluated for eligibility. After recruitment, twenty patients underwent the complete procedure with clinical and instrumental pre-operative and post-operative evaluation at the end of the follow-up. The Delos Postural Proprioceptive System (DPPS; Delos, Turin, Italy) was used to evaluate proprioceptive control through a monopodalic test performed with eyes open and closed. Clinical evaluation was performed by administering the following validated questionnaires: the American Orthopaedic Foot and Ankle Society (AOFAS) score and the Short Form-36 (SF-36) score. Results: Postural monopodalic tests showed that the affected limb displayed results slightly lower than pre-operative. According to the current data, TAR does not show an improvement in proprioceptive joint stability, and although the registered mean values do not present statistical significance, proprioceptive control shows data lower than the healthy limb. Both AOFAS ankle-hindfoot and SF-36 showed statistically significant improvement between pre-operative and postoperative assessments. Conclusions: The TAR procedure could have positive effects on the correction of joint deformities and pain relief, but, at the same time, could also have negative effects on proprioception due to the alteration of the joint structure. In conclusion, while the impact of TAR on proprioception is not well understood, it is a critical area for future research. Understanding the changes in proprioception following TAR could have significant implications for post-operative rehabilitation and long-term patient outcomes.