The objective of this study was to evaluate whether light-emitting diodes (LEDs) could be effective in a noninvasive, therapeutic device for the treatment of osteoarthritic (OA) knee joints.

Five weeks following the anterior cruciate ligament transection (ACLT) of mature New Zealand White rabbits, the animal knees were exposed to LED stimulation at intervals of 10min/day, 5days/week for 5weeks in the experimental group (n=7). The device used high intensity red and infrared (IR) LEDs with a total amount of energy delivered to the skin of 2.4J/cm². Animals were sacrificed at 9weeks postoperatively. Femoral surface gross morphology was evaluated with a modified Outerbridge classification and mRNA expression of catabolic and anabolic markers from femoral condyle cartilage and synovial tissue was assessed using RT-PCR. A control group was harvested 9 weeks following untreated ACLT.

Gross morphometry of the control group showed four Grade II, two Grade III and one Grade IV (average 2.6) condyles macroscopically. The experimental group showed two Grade I and five Grade II (average 1.7) (Table 1). mRNA expression of aggrecan in the cartilage showed no difference between the groups, however type II collagen expression increased in the experimental group compared with control. TNF-⍺ expression was significantly decreased in the experimental group compared to control.

There was general preservation of the articular surface and decreased levels of inflammation in the osteoarthritic joints with the application of LED therapy. This may provide potential application as a noninvasive treatment.