In vivo kinematic measurement of transfibular total ankle arthroplasty and natural ankles using bi-plane fluoroscopy.

BACKGROUND

We aimed to evaluate the in vivo kinematics of transfibular fixed-bearing total ankle arthroplasty (TAA) and compared them with those of natural ankles.

METHODS

Eleven TAA patients and 11 participants with natural ankles performed weightbearing and nonweightbearing dorsi-plantarflexion, deep squats, and kneeling. The activities were recorded using bi-plane fluoroscopy. The joint angles for each activity were estimated utilizing the model-image registration technique.

RESULTS

TAA restored physiological kinematic patterns, with consistent inversion and internal rotation during plantarflexion. However, the range of motion in the TAA group was significantly reduced compared to those of the natural ankles group. In deep squat and kneeling postures, joint angles in the TAA group were only 30-40 % of those in natural ankles.

CONCLUSION

Despite restoring physiological motion patterns, TAA demonstrated substantial limitations in mobility, emphasizing the need for advancements in surgical techniques and implant design.

LEVEL OF EVIDENCE: IV.