Biological Regeneration of Articular Cartilage in an Early Stage of Compartmentalized Osteoarthritis: 12-Month Results

Background: Biological regeneration in an early stage of osteoarthritis (OA) is an important clinical challenge. An early-stage compartmentalized OA model was used to evaluate different biological regeneration techniques.

Hypothesis: Biological regeneration in an early stage of compartmentalized OA is possible.

Study design: Controlled laboratory study.

Methods: A 7-mm cartilage defect was surgically created in 24 sheep. After 3 months, by which time early OA had set in, the sheep were randomized into 4 different treatment groups and operated for the second time. One group (CONTROL) served as a long-term follow-up group for the further development of OA. The other 3 groups (regeneration groups) each underwent a different regeneration procedure after abrasion of the subchondral bone (defect size: 20 × 10 mm with a depth of 2.5 mm): spongialization alone (SPONGIO), spongialization followed by implantation of an unseeded hyaluronan matrix (MATRIX), or spongialization followed by implantation of a hyaluronan matrix seeded with autologous chondrocytes (MACT). Then, 12 months after the second operative procedure, the animals were euthanized and the defects subjected to macroscopic and histological grading. Historical 4-month data were compared with the 12-month results.

Results: After 12 months of follow-up, advanced cartilage degeneration was observed in the CONTROL group. On the other hand, all regeneration groups improved significantly compared with the 4-month results using the Mankin score. Cartilage quality in the MACT group was significantly better than in the MATRIX group, as determined by the Mankin and the O'Driscoll scores.

Conclusion: There are no existing clinical options for preventing early OA from progressing to a severe disease. This study provides important information on how a surgical intervention can forestall the development of OA.

Clinical relevance: OA of the knee is very common. Total joint replacement is not an acceptable option for active patients. Biological regeneration in OA is successful for focal cartilage defects; however, a long-term follow-up for biological regeneration in OA is missing. It is essential to have long-term results for a regenerative procedure involving cartilage, which is a tissue with a very slow turnover.