Effects of rotation and osteotomy angulation on patellar tendon insertion position during circular tibial tuberosity osteotomy.

OBJECTIVE

To evaluate the influence of rotation of the tibial tuberosity (TT) in the sagittal plane and angulation of osteotomy in the frontal plane (FPA) on the displacement of patellar tendon (PT) insertion.

STUDY DESIGN

Ex vivo biomechanical study.

SAMPLE POPULATION

Canine tibiae (n = 36).

METHODS

Nine groups of 4 tibiae each had a circular osteotomy of the TT at an FPA from -20° to +20° with increments of 5° for each group. The osteotomized TT was rotated by angles of rotation (AORs) of 10°, 20°, or 30° in the sagittal plane. The craniocaudal (CCD), distoproximal (DPD), and mediolateral (MLD) displacements of a marker located at the PT insertion on the TT were evaluated radiographically. Differences between groups were analyzed by Mann-Whitney U test and Friedman 2-way ANOVA.

RESULTS

There was a significant correlation between the AOR and CCD. A positive FPA resulted in a high CCD and lateral shift of the TT at every AOR. Performing an osteotomy at an FPA of 0° produced the maximum amount of DPD.

CONCLUSIONS

FPA and AOR during circular osteotomy of the TT influence the final displacement of the PT insertion in all 3 planes.