Quasi-static mechanical evaluation of canine cementless total hip replacement broaches: effect of tooth design on broach and stem insertion.

backgroundBiomedtrix BFX

resultsBroach tooth design led to significant differences in broaching energy and peak broaching loads in test blocks of both densities. In low density test blocks, TG1 required the lowest cumulative broaching energy (10.76 ±0.29 J), followed by Control (12.18 ±1.20 J) and TG2 (16.66 ±0.78 J) broaches. In high density test blocks, TG1 required the lowest cumulative broaching energy (32.60 ±2.54 J) as compared to Control (33.25 ±2.16 J) and TG2 (59.97 ±3.07 J).  During stem insertion and subsidence testing, stem insertion energy for high density test blocks prepared with Control broaches was 14.53 ± 0.81 J, which was significantly lower than blocks prepared with TG1 (22.53 ± 1.04 J) or TG2 (19.38 ± 3.00 J) broaches. For stem subsidence testing in high density blocks, TG1 prepared blocks required the highest amount of energy to undergo subsidence (14.49 ± 0.49 J), which was significantly greater than test blocks prepared with Control (11.09 ±0.09 J) or TG2 (12.57 ± 0.81 J) broaches.

conclusionsThe additional V-grooves in TG1 broaches demonstrated improved broaching performance while also generating press-fit envelopes that were more resistant to stem insertion and subsidence. TG1 broaches may prove useful in the clinical setting; however additional studies that more closely simulate clinical broach impaction are necessary prior to making widespread changes to THR broaches.