Dynamic subtalar joint space measurement analysis following tibiotalar arthrodesis and total ankle replacement

Tibiotalar arthrodesis and total ankle replacement are current standards for treating end-stage ankle osteoarthritis. Our clinical understanding of biomechanical causes and risk factors for subtalar secondary osteoarthritis development following surgical treatment is limited. The objective of this retrospective study was to investigate subchondral bone morphometric differences of individuals treated with a tibiotalar arthrodesis or ankle arthroplasty that may influence subtalar joint measurements during overground walking; results were compared between surgical groups, their unaffected limb, and asymptomatic controls.

Previously collected kinematics were used to measure and compare subtalar joint space and congruence throughout the dynamic activity utilizing a correspondence-based joint measurement analysis. A morphometric analysis evaluated subchondral bone differences of the calcaneus subtalar joint between groups.

The affected subtalar joint of arthrodesis participants showed increased joint space distance in the medial facet during early stance that was related to kinematic differences compared to controls and their contralateral untreated limbs. Our morphometric analyses demonstrated subchondral bone asymmetries in both surgical groups compared to their contralateral untreated limbs.

Previously reported kinematic differences between treated and untreated limbs in arthrodesis participants may translate to the variations in joint space and morphology observed in this study. Our earlier findings within the arthroplasty group indicated no significant kinematic differences between treated and untreated limbs, and the current study showed minimal significant differences in joint space distances. Collectively, this suggests that arthroplasty joint space and subchondral bone shapes are not as strongly influenced by functional asymmetries as those in the arthrodesis group.