[Purpose] Superficial heat treatment is one of the most widely used physical therapies
for osteoarthritis (OA). We clinically evaluated the effects of local heat treatment and
exercise therapy for knee OA, and evaluated the articular cartilage using magnetic
resonance imaging (MRI) T2 mapping. [Subjects and Methods] Eighteen females aged 50–69
(59.5 ± 8.5 years, mean ± SD) years diagnosed with early-stage knee OA were randomly
assigned using computer-generated random numbers to either a local heat treatment group
(LH group, 9 subjects) or an exercise therapy group (EX group, 9 subjects). These groups
were subjected to a 12-week intervention experiment. MRI T2 mapping was performed for
cartilage imaging and quantitative evaluation. For clinical evaluation, the Japanese Knee
Osteoarthritis Measure (JKOM) and the Timed Up and Go (TUG) test were performed. Both
clinical and MRI evaluations were performed at the beginning and end of the intervention
(0 week (Time 0) and 12 weeks). [Results] The total JKOM score had a significantly
decreased in the LH group at 12 weeks. However, in the EX group the total JKOM scores at
Time 0 and 12 weeks were not significantly different. The TUG time in the EX group was
significant shorter at 12 weeks, whereas it showed no significant change in the LH group
at 12 weeks, though the TUG times of 7 of the 9 patients decreased, exhibiting some
improvement. The T2 value of the LH group was significantly shorter at 12 weeks. However,
the T2 value in the EX group showed no significant change at 12 weeks. [Conclusion] After
local heat treatment using heat- and steam moisture-generating sheets for 12 weeks, we
observed improvements in clinical symptoms and walking abilities. Moreover, positive
effects on cartilage metabolism were suggested.