Cam impingement of the posterior femoral condyle in unicompartmental knee arthroplasty

Purpose There has been much emphasis on the importance of cam impingement, which is a cause of pain and knee hyperflexion restriction in unicompartmental knee arthroplasty (UKA). This study aimed to correlate cam impingement in the posterior femoral condyle with an α-angle showing the severity of the impingement. Methods The study groups consisted of 87 knees of 74 patients operated on with phase 3 medial Oxford UKA. Postoperatively, Group A (68 knees, 78.2 %) had no remnant of cam lesion; Group B (19 knees, 21.8 %) had cam lesion remnants. In Group C (18 knees, 20.7 %), which is a subgroup of Group A, cam lesions seen preoperatively were cleaned and not seen postoperatively. Results The mean increase in active flexion was 20.4° (±7.3°) in Group A, 9.7° (±6.1°) in Group B and 20.8° (±7.3°) in Group C. The difference between Group A and Group B and between Group B and Group C was statistically significant ( p