Magnetic Resonance Imaging Pre and 4 Months Post 6 Physiotherapy Treatments for OA Knee Pain - A Pilot Study

The source of osteoarthritic (OA) knee pain is perplexing. Bone marrow Lesions (BMLs) and the Infrapatellar Fat Pad (IPFP) are hypothesized to cause symptoms in this patient population. With escalating costs for OA treatment, physiotherapy could be an inexpensive option for managing OA knee pain. The aim of this study was to examine the Magnetic Resonance Imaging (MRI) of OA knee pain patients, pre and post, a specific physiotherapy program to determine if there were any changes in patellar position, IPFP volume and appearance as well as BMLs. The study included 12 patients with radiological evidence of tibio-femoral, patello-femoral or tri-compartmental OA. 1.5 T MRIs were obtained pre and 4 months post 6 physiotherapy sessions. MRI comparisons were made for changes in (a) IPFP oedema signal b) patellar alignment c) IPFP depth, area and perimeter and d) cyst presence or size in the subspinous tibial bone marrow and subchondral bone marrow. After treatment, both pain scores and IPFP signal reduced in all subjects. The patella was 1.7 mm higher (p=0.004), 1.2 mm more medial (patellar drift, p=0.0001) and 2° more varus (patellar roll, p=0.001). No consistent pattern was found in distribution, size or intensity in BMLs. IPFP oedema seems to be associated with increased pain in knee OA.