Newman M, Bertollo N, Walsh W, et al.
OBJECTIVES: To evaluate the degree of lateralization achievable and strength of tibial tuberosity transposition and advancement (TTTA) relative to pin and tension band wiring (PTBW) for lateral tibial tuberosity transposition. METHODS: Six pairs of cadaveric tibiae were used. Tibial tuberosity position was determined with computed tomography (CT); bones were then randomly assigned into TTTA and PTBW groups. The PTBW group had a tibial tuberosity osteotomy and fixation with pin and tension band wiring. The TTTA group had a tibial tuberosity advancement performed with lateralization of the tibial tuberosity by 50% of cage depth, using spacers on the cranial cage screw. Postoperative CT images showed lateralization and craniocaudal deviation. Single axial distractive loading was applied to the patella at 90 to the tibial plateau, and peak load, energy, and stiffness were calculated. RESULTS: There were significant differences in lateralization (PTBW: 67.92 +/- 5.1 %; TTTA: 88.51 +/- 5.5 %) (p = 0.0173) and craniocaudal deviation (PTBW: -8.30 +/- 1.4 %; TTTA: 6.83 +/- 0.6) (p = 0.0001). There were no significant differences in peak load to failure (N) (PTBW: 1448 +/- 121; TTTA: 1597 +/- 43) (p = 0.4541), energy to failure (N/mm) (PTBW: 15013 +/- 2719; TTTA: 17314 +/- 887) (p = 0.646), or stiffness (N/mm)(PTBW: 102.8 +/- 4.7; TTTA: 92.9 +/- 4.8) (p = 0.2716). CLINICAL SIGNIFICANCE: The TTTA was more effective at lateralization of the tibial tuberosity, and of comparable strength to PTBW. Greater support of the osteotomized fragment with TTTA may resist cyclic loading, and requires evaluation.