Effect of physical therapy on early knee osteoarthritis with medial meniscal posterior tear assessed by MRI T2 mapping and 3D-to-2D registration technique: A prospective intervention study

Objectives: The purpose of this study was to verify that exercise aimed at improving knee kinematics in early-stage knee osteoarthritis (OA) patients with medial meniscus posterior root tears (MMPRTs) reduces knee adduction angle during gait and prevents rapid cartilage degeneration in the medial compartment of the knee. Methods: Subjects were randomly assigned to an adapting alignment exercise (AAE) group, with the goal of improving knee kinematics, and a muscle training and exercise (MTE) group. Before the start of the six-month intervention and following its completion, we performed an analysis of knee kinematics during gait using a 3D-to-2D registration technique and identified the area of cartilage degeneration using MRI T2 mapping. Results: The amount of change between pre- and post-intervention measurements of the maximum angle of adduction was 0.48° (95% CI: −0.14, 1.09) in the MTE group and −0.40° (−0.84, 0.04) in the AAE group (p = .039). The amount of change in the area of cartilage degeneration according to MRI T2 mapping expressed as MTE/AAE group was 7.7 mm 2 (−0.4, 15.8)/−2.7 mm 2 (−10.8, 5.3) at the posterior knee (p = .043). Conclusion: AAE could be a potential treatment method that improves the natural course of knee OA with MMRPTs.