ABSTRACT
OBJECTIVE: 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. DESIGN: 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 10 min/day, 5 days/week for 5 weeks 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 2.4 J/cm(2). Animals were sacrificed at 9 weeks 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. RESULTS: 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-α expression was significantly decreased in the experimental group compared to control. CONCLUSIONS: 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.
Subject(s)
Osteoarthritis/therapy , Phototherapy , Aggrecans/biosynthesis , Aggrecans/genetics , Animals , Anterior Cruciate Ligament/metabolism , Anterior Cruciate Ligament/pathology , Cartilage, Articular/metabolism , Cartilage, Articular/pathology , Collagen Type II/biosynthesis , Collagen Type II/genetics , Female , Knee Joint/metabolism , Knee Joint/pathology , Osteoarthritis/genetics , Osteoarthritis/metabolism , Osteoarthritis/pathology , RNA, Messenger/biosynthesis , RNA, Messenger/genetics , Rabbits , Reverse Transcriptase Polymerase Chain Reaction , Tumor Necrosis Factor-alpha/biosynthesis , Tumor Necrosis Factor-alpha/geneticsABSTRACT
BACKGROUND: Fresh human osteochondral allografting is a biological cartilage replacement technique used to treat articular and osteoarticular defects in the knee. A small number of grafts fail, and we analyzed every retrieved graft during a 4-year period in order to learn more about the potential causes of failure. HYPOTHESIS: A large percentage of chondrocytes still remain viable many years after fresh osteochondral allografting. STUDY DESIGN: Descriptive laboratory study. METHODS: Retrieval specimens were obtained at the time of revision surgery and immediately analyzed. Chondrocyte viability and viable cell density were determined using a live/dead staining technique followed by confocal microscopy. Glycosaminoglycan content was a measure of the cartilage matrix. Radiolabeled sulfate uptake served as a biochemical marker of chondrocyte metabolic activity. Cartilage and subchondral bone were examined histologically. RESULTS: Fourteen patients yielded a total of 26 retrieval specimens that had been originally implanted as individual fresh osteochondral allografts. Average graft survival was 42 months. Chondrocyte viability was 82% +/- 17%, and chondrocyte viable cell density was 15 590 +/- 5900 viable cells/mm(3). Retrieved tissue demonstrated radiolabeled sulfate uptake of 437 +/- 270 counts per minute and 3.5% +/- 0.8% hexosamine per dry weight. Histologically, all specimens showed some degree of cartilage fibrillation. There was evidence of bone allograft incorporation in most specimens, as well as pannus formation in 4 specimens, but no evidence of immune rejection. CONCLUSION: A small percentage of fresh osteochondral allografts fail, but the precise cause is unknown. The main theories for failure investigated here include immunologic rejection, failure of bony incorporation, and chondrocyte death causing breakdown of the cartilage matrix. We show that chondrocytes remain viable many years after transplantation, allograft bone incorporates, and immune rejection does not seem to play a primary role in failure. CLINICAL RELEVANCE: Fresh osteochondral allografting is becoming more common in the treatment of articular cartilage defects in the knee. Our findings support the paradigm of fresh osteochondral allografting, the transplantation of hyaline cartilage with biological incorporation of the underlying bone scaffold. The reasons for failure of a small percentage of grafts remain unclear.