Paper 266: Viability Assessment of Intraarticular Osteochondral Knee Fragments

Abstract

Viable cells are essential for cartilage remodeling. However cartilage viability might be affected once it is detached from its anatomic location as cartilage nutrition is maintain partly by the subjacent subchondral bone. Our study was aimed to determinate if chondrocyte isolated from osteochondral free knee fragments are viable. A consecutive series of 5 patients (5 knees) with unstable lesions of osteochondritis dissecans (OCD) treated with arthroscopic internal fixation were included. There were 5 males with a mean age of 21 (18-24). The mean duration of the symptoms was 5 months (2 to 9). During arthroscopy the detached osteochondral fragment was assessed and reattached with titanium Herbert screw. Cartilage biopsy was performed from the detached osteochondral fragment (Study Group). To establish a control group a biopsy from healthy native cartilage (weight bearing portion of the medial femoral condyle) was also performed. Specimens obtained during arthroscopy procedure were taken to the laboratory in 5% medium assessing that cartilage surface was always maintained wet till the digestion was started. Digestion with Pronase (50mg/ml) for one hour followed by 12 hours of Collagenase (0.36 mg/ml) was performed. Tissue viability was assesed using live-dead assay. Percentage of live cells was established. T student and confidence interval was used for assessing statistical difference. A p value<0, 05 was considered significant. Study group showed 88% of viable cells ± 2.1 (CI 95%50-100). Control group showed 92% viability ±0.5 (CI 95%50-100) (p=0,002). These findings suggest that chondroctyes from detached osteochondral fragments are able to maintain their viability once they are detached from their anatomic location. Probably the synovial fluid might contribute as an important source of nutrition under this pathological situation.