Chondral injuries of the knee are extremely common and present a unique therapeutic challenge due to the poor intrinsic healing of articular cartilage. These injuries can lead to significant functional impairment. There are several treatment modalities for articular osteochondral defects, one of which is autologous chondrocyte implantation. Our study evaluates the mid to long term functional outcomes in a cohort of 828 patients who have undergone an autologous chondrocyte implantation procedure (either ACI or MACI), identifying retrospectively factors that may influence their outcome. The influence of factors including age, sex, presence of osteoarthritis and size and site of lesion have been assessed individually and with multivariate analysis. All patients were assessed using the Bentley Functional Score, Visual Analogue Score and the Cincinnati Functional Score. Assessment were performed pre-operatively and of their status in 2010. The longest follow-up was 12 years (range 24 to 153 months) with a mean age of 34 years at time of procedure. The mean defect size was 409 mm. 2. (range 64 to 2075 mm. 2. ). The distribution of lesions was 51% Medial Femoral Condyle, 12.5% Lateral Femoral Condyle, 18% Patella (single facet), 5% Patella (Multifacet) and 6% Trochlea. 4% had cartilage transplant to multiple sites. High failure rates were noted in those with previous cartilage regenerative procedures or evidence of early osteoarthritis and those with transplantation to multiple sites. Autologous chondrocyte implantation is an effective method of decreasing pain and increasing function, however patient selection plays clear role in the success of such procedure

Background. An osteochondral defect in the knees of young active patients represents a treatment challenge to the orthopaedic surgeon. Early studies with allogenic cartilage transplantation showed this tissue to be immunologically privileged, showed fresh grafts to maintain hyaline cartilage, and surviving chondrocytes several years after implantation. Methods. Between January 1978 and October 1995 we enrolled 63 patients in a prospective non-randomised study of fresh osteochondral allografts for post-traumatic distal femur defects in our institute. Five international patients who were lost to follow-up were excluded from this study. The indications for the procedure were: patients younger than 50 years of age having unipolar post-traumatic defects, or osteochondritis dissecans larger than three cm in diameter and one cm in depth. Results. Fifty-eight patients, ages 11-48 (mean 28) were followed for 15-32 years (mean 21.8 years). Thirteen of the 58 grafts have subsequently required further surgery, with three having graft removal and ten converted to total knee arthroplasty. Three patients died during the study due to unrelated causes and are included in the survivorship curve. Kaplan-Meier survivorship analysis showed: 91%, 84%, 69%, and 59% graft survival at 10, 15, 20, and 25 years, respectively. Patients with surviving grafts had good function, with a mean modified Hospital for Special Surgery score of an average 86 at 20 years or more following the allograft transplantation surgery. Late osteoarthritic degeneration as was seen on radiographs was associated with lower Hospital for Special Surgery scores representing patients with poorer clinical outcome. Conclusion. The authors confirm the value of fresh osteochondral allograft as a long term solution for articular defect in the knees of young patients. We recommend the use of fresh osteochondral allograft for treatment of large osteochondral defects in the distal femur of young and active patients