Figure 1.

Diagram of measured patellar alignment indices. (a) In the sagittal plane, PL is the inner patellar length and TL is the patellar tendon length (PLR, the patellar length ratio, was computed as PL/TL). (b-d) In a transverse (axial) plane, SA is the sulcus angle (b) and LPTA is the lateral patellar tilt angle (c); (d) diagram of bisect offset (BO) measurement.