Lateral-Wedge Insoles Reduced Joint Loading Rates In Patients With Anterior Cruciate Ligament Deficiency During Walking

PURPOSE: This study aimed to identify the effects of lateral-wedge insoles (LWIs) with different degrees on lower-limb joint loading rates in patients with anterior cruciate ligament deficiency (ACLD) during walking. METHODS: Twelve patients with unilateral ACLD (ACLD group) and 12 healthy controls (Control group) walked while wearing regular walking shoes with lateral-wedge insoles (LWI) of different degrees (i.e., 0°, 3°, and 6°). Using the measured ground reaction force (GRF) and kinematic data, the intersegmental forces acting between two adjacent body segments were calculated using inverse dynamics analysis. The medial-lateral and axial forces at the ankle, knee, and hip were obtained by projecting the corresponding intersegmental forces onto the axes of the local coordinate systems of the distal segment. Loading rates (LRs) on the GRFs and the joint forces during the loading response were determined as the maximum instantaneous slope of these force curves. For between-subject comparisons, all force-related data were normalized to body weight. RESULTS: Compared to the Control, the ACLD group showed increased LRs of the GRF and all joint forces in both the medial-lateral and vertical directions in both limbs, except for the sound-side limb when wearing a 6-degree LWI. With increasing LWI degrees, the LRs of the GRF and all joint forces in both limbs decreased linearly in the ACLD group but no significant effects were found in the Control group. The ACLD group increased LRs of the GRF and all joint forces of the injured limb compared to the sound limb for all degrees of LWI. CONCLUSION: For patients with ACLD, wearing shoes with LWI can reduce the LRs of the GRF and all joint forces in the medial-lateral and vertical directions in both limbs, with a 6-degree LWI effectively normalizing the LRs. The findings indicated that the use of LWI can potentially be an effective preventative approach for reducing the risk of progressive premature knee osteoarthritis in athletes with ACLD.