Query: The treatment of discrete but advanced cartilage damage to the knee joint, such as in osteonecrosis in patients older than 45 years, has not been satisfactorily resolved to date. The objective of this prospective study was to investigate the utility of a minimally-invasive unicondylar surface replacement system and to record the first clinically-obtained results.

Method: We are reporting on the results of the first 19 operations of discrete knee joint defects performed in our clinic since October 2004 using the Arthrosurface System. The Arthrosurface System consists of specially-preformed convex implantate dowels and an adapted integrative fraise system for handling the femurcondylus. The knee joint function, the activity level and the patient’s quality of life were evaluated pre–and postoperative using the Knee Society Score, the Tegner Activity Index and the Lysholm Score.

Results: In the operating room, the system was impressive in its utility. No implantate-related complications have occurred in the short follow-up time thus far. In the early postoperative phase, the patients achieved rapid increase in their activity level which paralleled the reduction in pain relief attained.

Conclusion: The Arthrosurface^® System shows beneficial properties for treating localized but advanced cartilage damage to the knee joint of patients older than 45 years of age. In particular, it enables arthroscopically-supported minimally-invasive implantation. Intact structures are thus not damaged and the patient rehabilitation is rapid.