Unicondylar knee arthroplasty. An evaluation of selection criteria.

In a prospective evaluation of 165 consecutive patients (228 knees), intraoperative evaluation of the knees was performed at the time of total knee arthroplasty. Each of the three knee compartments was independently graded for arthritic changes depending on the extent of articular degeneration visualized. Patients were believed to be suitable candidates for unicondylar knee arthroplasty (UKA) if they fulfilled the Kozinn and Scott criteria. Specific attention was given to patient age, weight, preoperative range of motion, angular deformity, as well as the extent of intraoperative cartilage erosions seen. Thirty-five knees (15%) were candidates for UKA based solely on inspection of the articular surfaces at the time of surgery. Further analysis revealed that of these 35 knees, 22 failed to meet the other selection criteria. Thus, of the original 228 knees, only 13 knees (6%) fulfilled all of the stringent selection requirements and were considered suitable candidates for UKA. With proper patient selection, the number of UKAs performed could become relatively small.