Lateral patellar translation effects after arthroscopic partial meniscectomy of torn discoid lateral meniscus

To investigate the effects of arthroscopic partial meniscectomy of torn discoid lateral meniscus on patellar tracking.

In all, 112 patients (112 knees) who underwent arthroscopic partial meniscectomy participated in the study. All subjects were examined with standing weight-bearing magnetic resonance imaging (MRI) preoperatively and one month postoperation. Axial-plane images through the maximum width of the patella and the maximum dorsal area of the femoral condyles were superimposed and the bisect offset index used to quantify patellar translation. Differences between pre- and postoperation in the bisect offset indexes were calculated and compared by Student's paired t-test. P < 0.05 was considered statistically significant.

Before surgery, the mean bisect offset index was 0.574 (0.437-0.692). One month postoperation, the mean bisect offset index was 0.622 (0.510-0.801). The postoperation bisect offset index increased by an average of 0.048 (-0.018 to 0.129) compared with the preoperation value; this difference is statistically significant result (t = 18.33, P < 0.01).

After arthroscopic partial meniscectomy, the patella translates more lateral to the femoral trochlear groove. These results suggest that arthroscopic partial meniscectomy may result in patellar maltracking.