Biomechanical testing of a β-tricalcium phosphate wedge for advancement of the tibial tuberosity

Objectives: to evaluate in vitro the strength; of different compositions of beta-tricalcium; phosphate (13=TCP) wedges in comparison with titanium foam and cages. To study the response to cyclic loading of the strongest B-TCP wedge, titanium foam and titanium; cage.; Methods: Compression test: Twenty-five tibiae were prepared for tibial tuberosity advancement using the Modified Maquet technique. Five groups were defined depending on the material used to maintain the tibial tuberosity:. Group 1 = titanium cage;; Group 2 = wedges Of porous titanium foam with 50% porosity (OrthoFoarn); Group 3 =blocks Of biphasic synthetic bone (60% hydroxyapatite [HAP] and 40% beta-TCP, porosity 80%); Group 4 = blocks of biphasic synthetic bone (60% HAP and 40% beta-TCP, porosity 70%) and Group 5 = blocks of; biphasic synthetic bone (65% HAP and 35% 13-TCP, porosity 60%). Loads to failure were calculated for each implant. Cyclic study: Five additional tibiaes of group 1, 2 and 5 were fatigue tested from 100 to 500 N at a rate of 4 Hz for 200,000 cycles or until failure. Results: Compression test: For the five; groups, the mean load at failure was 1895 N, 1917 N, 178 N, 562 N and 1370 N respectively. Cyclical study: All samples in the three 1 groups tested withstood 200,000 cycles; without failure. Clinical Significance: The ideal implant to maintain tibial tuberosity advancement after; the modified Maquet technique would be absorbable and allow oSteoconduction and; osteoinduction. As such, (beta-TCP wedges have; many advantages and our study shows that they can withstand loads in the patellar tendon up to 500 N over 200,000 cycles in vitro and deserve more investigation.