Immediate effects of leg‐press exercises with tibial internal rotation on individuals with medial knee osteoarthritis

Abstract Objective Although patients with knee osteoarthritis (OA) demonstrate abnormal kinematics involving greater tibial external rotation during squatting, there have not been any previous studies investigating an exercise focused on correcting knee rotational kinematics. This study aimed to determine the immediate effects of exercise with tibial internal rotation (IR) on symptoms and functions in patients with knee osteoarthritis (KOA). Methods This study provides Level II evidence using a small randomized controlled trial. Sixty patients were allocated to either the tibial IR or neutral rotation (NR) group in this randomized controlled trial. The IR group performed a leg press activity with the tibia in maximal IR, whereas the NR group performed leg press activity with the tibia in NR. Outcome measures were (a) 10‐m walk test; (b) Timed Up and Go test, (c) knee flexion angle while squatting, (d) knee pain during walking and squatting, and (e) difficulty during walking and squatting. Results Significant interaction was observed in all outcomes. The IR group exhibited significant improvement on all outcome measures, whereas the NR group exhibited significant improvements only in the 10‐m walk. Conclusion The IR group exhibited greater improvements than the NR group on all outcome measures. After a single session, leg press activity with the tibia in maximal IR improved the symptoms and functions measured in this study more effectively than leg press activity with the tibia in a neutral position. This suggests that correcting rotational malalignment is more important than strengthening the quadriceps for maintaining or even improving function of OA knees. (Clinical trials registration number: UMIN000021751)