High tibial osteotomy: long term survival analysis and patients' perspective.

High tibial osteotomy has been generally accepted as a useful treatment for unicompartment osteoarthritis of the knee to improve a patient's quality of life. Few studies have examined the outcome from the patient's perspective. A survival analysis of one to twenty-one years was conducted on 67 knees including analysis of the patients' satisfaction level with this procedure. Cumulative survival probability of 89.5% at 5 years, 74.7% at 10 years and 66.9 % for 15 and 20 years was reported. Ninety-one percent of patients had improvement in pain score and would choose to have this surgery again. Average patient satisfaction level was 75.5%. Forty-eight percent of patients were able to perform at a higher level of activity than before surgery, although none was able to perform at the level prior to the onset of knee pathology. It was concluded that this procedure was able to improve a patient's quality of life and achieved high satisfaction among patients. There is an increasing role of high tibial osteotomy as an adjunct to an autologous chondrocyte implantation procedure.

Subchondral bone overgrowth in the presence of full-thickness cartilage defects in the knee.

Between October 2000 and December 2003, 252 autologous chondrocyte implants were performed in 183 patients. Eighty lesions showed overgrowth of the subchondral bone plate under the chondral lesion, this was termed a "bone boss." Thirty-seven were on the medial femoral condyle (MFC), 18 on the lateral femoral condyle (LFC), 21 in the trochlea and 4 on the patella. There was a statistically significant association between the LFC and "bone boss." The lesions showing this finding were of a larger area (3.4 cm2 and 2.8 cm2 respectively, p=0.006), and had more diffuse chondral changes than lesions without. The patients with a "bone boss" had a tendency to longer duration of symptoms (85.3 months and 64.3 months respectively, p=0.089). The "bone bosses" were resected back to the level of the surrounding subchondral bone prior to implantation. Radiological and clinical follow-up showed no statistical difference between the two groups. A discussion of the possible aetiology of the "bone boss" is made.