Purpose of the study: Spontaneous repair of lost deep chondral tissue is minimal in the knee joint. A clinical trial of chondrocyte autografts as described by Brittberg and Peterson was undertaken by the Nantes University Hospital and the French Society of Arthroscopy in 1999.

Material and methods: Twenty-eight patients, mean age 28 years, underwent surgery in eight centers. Etiologies were: osteochondritis (n=14), isolated posttraumatic chondorpathy (n=7), chondropathy and full-thickness ACL tear (n=7). All lesions involved the condyles and were deep (ICRS grades 3 and 4). Mean surface area involved after debridement was 490 mm2 (range 150–1000 mm2). Patients were followed three years after the autologous grafting to assess functional outcome. An MRI was obtained at 2–3 years. Thirteen control arthroscopy procedures were performed including eight with biopsy specimens for histology and immunohisto-chemistry studies.

Results: Twenty-six patients were reviewed at more than two years. There were no general complications, three patients presented a partial avulsion of the graft treated by arthroscopy and one underwent arthrolysis at six months. Function improved in all patients except three and pain improved in all. The ICRS score improved from 43 points (range 19–70) to 77 points (range 39–84). Sixteen control MRIs were available and showed that the graft was hypertrophic in eleven cases, on level in four, and insufficient in one. Marginal integration was good in 11 cases and partial in five. Subchondral integration was complete in ten cases and mediocre in six. The arthroscopic score was nearly normal (score 8–11) in eight cases and abnormal in five (score 4–7). The histological class according to Knutsen (hyaline richness) was: one in group 1 (> 60%), three in group 2 (> 40%), four in group 3 (< 40%) and one in group 4 (bony or fibrous tissue). Function score (r=0.78 and MRI score (r=0.76) were correlated with arthroscopic sores. There was no correlation with the histological results.

Discussion: Clinical outcome was improved in more than 80% of cases, similar to results reported for histological series. The arthroscopic and histological results were equivalent to those reported by Knutsen but inferior to those reported by Bentley or Peterson.