Effect of low-intensity pulsed ultrasound therapy on a rat knee joint contracture model.
Masanori Watanabe, Satoshi Kojima, Masahiro Hoso
PMID 28931989WHAT IT FOUND
In rats with knee contracture, four weeks of low-intensity pulsed ultrasound was associated with less extension limitation and lower capsule density than untreated rats.
This is animal data, not patient evidence.
Key findings
01Before treatment, the immobilized rats that later received LIPUS and those that did not did not differ in extension-limiting angle.
02After four weeks, the LIPUS group's extension-limiting angle was 31.1 ± 9.2° and the non-treatment group's was 42.3 ± 5.6°, with a significant difference.
03Capsule density was 53.3 ± 7.5% in controls, 77.2 ± 5.7% in non-treatment rats, and 69.2 ± 2.9% in LIPUS rats, with significant differences across groups.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The study was done in rats, not people, so it cannot show what would happen in a patient. Only 6 non-treatment rats and 7 treatment rats were compared after immobilization. The paper says LIPUS may also have stimulated skin, fascia and muscles, so the effect cannot be assigned only to the joint capsule. Capsule findings were histological observations, and the paper says quantitative assessments require further refinement. The outcomes were knee angle and capsule tissue in rats, not patient function.
Declared interests
The authors declared no conflict of interest.
The easy way to misread this
Do not conclude that low-intensity pulsed ultrasound treats knee contracture in patients. The study was done in rats, and the authors say the ultrasound may also have affected skin, fascia and muscles, so the effect cannot be assigned only to the joint capsule.