Deep heat therapy system with resonant cavity applicator for articular cartilage in knee osteoarthritis.
Yasuhiro Shindo, Kenji Takahashi, Futoshi Ikuta and 3 others
PMID 33362353WHAT IT FOUND
A prototype device heated deep knee cartilage in three healthy men without warming the skin or causing burns.
It did not test pain or function in osteoarthritis. This shows the machine works physically, not that it treats patients.
Key findings
01The resonant cavity applicator raised the normalized temperature in the cartilage region to 0.8 (80% of the maximum), whereas the microwave diathermy system only reached 0.1 (10%).
02All three volunteers experienced almost no sensation of heat in the knee and showed no burns or other adverse reactions during the 20 W heating.
03The study measured temperature distribution in healthy volunteers, so the effect on osteoarthritis knees remains unknown.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The study involved only three healthy male volunteers, so the results may not apply to women or people with knee pathology. The researchers measured the distribution of temperature increase but not the actual physical temperature inside the tissue, so they cannot confirm if the target therapeutic temperature was reached. The study did not include patients with osteoarthritis, so the therapeutic effect on pain or function is completely unknown. This was a safety and feasibility test of a prototype device, not a clinical trial of treatment efficacy.
Declared interests
One author (KK) has a patent for the heat therapy system used in this study. The work was supported by a JSPS KAKENHI grant.
The easy way to misread this
Do not assume this device treats knee osteoarthritis. The study tested three healthy men to prove the machine can heat deep tissue without burning the skin. It did not test pain, stiffness, or function in patients with OA, so there is no evidence of clinical benefit yet.