33rd Annual Scientific Meeting proceedings

Introduction
There is controversy regarding the efficacy of block recession trochleoplasty (BRT) in cats. This prospective study aimed to report femoro-patellar joint congruency by computed tomography (CT) following BRT.

Materials and Methods
Six cats (median age 56 months (range 15-86 months)) with 10 stifles with grade 2 and 3 MPL (n=5, respectively) were enrolled. Standard BRT was performed using parallel saw cuts centered on the cranial aspects of the trochlear ridges with modular osteotome and mallet. Standardized measurements of the trochlear groove (width, depth, and area) and patella (recessed area) were performed on preoperative (T0), postoperative (T1), and 6-week recheck (T6) CTs with stifles in extended and flexed position. Groove measurements obtained from flexed and extended stifles were combined for statistical analysis, whereas recessed patellar area (RPA) measurements were evaluated separately. Measurements at different time-points were analyzed for correlation and significance (Student-t-test and Pearson correlation).

Results
Mean femoral trochlear area and trochlear depth increased significantly between T0-T1 (5.49±3.9 mm2; 0.80±0.6 mm), T1-T6 (4.41±7.0 mm2; 0.41±0.9 mm) and T0-T6 (9.9±3.1 mm2; 1.21±0.3 mm) respectively (P< 0.05). Mean RPA significantly increased between T0-T1 (1.90±1.4 mm2), T1-T6 (2.64±3.2 mm2), and T0-T6 (4.54±1.9 mm2) when the stifle was flexed and between T0-T1 (1.48±1.1 mm) and T0-T6 (1.41±1.0 mm) when the stifle was extended (P<0.05). Mean trochlear width increased significantly between T0-T6 (0.94±0.7 mm; p<0.05). No cats had MPL recurrence.

Discussion
Block recession trochleoplasty improved patellar congruency immediately after surgery, and further improvement was documented during the 6-week postoperative time.