Impaction grafting for femoral component revision in a goat model using washed morselized cancellous allograft

To determine whether washing morselized cancellous bone allograft in impaction grafting for revision hip arthroplasty would improve mechanical and biologic performance, left hip hemiarthroplasty with a collarless stem cemented into impacted morselized cancellous bone was performed in 22 goats. Washed allograft was used in the experimental group, and standard allograft was used in the control group. One of 11 experimental and 4 of 11 control implants were observed to be loose at 8 weeks. Washing allowed significantly more morselized cancellous bone to be placed in the experimental group compared to the control group (7.7+/-1.9 and 6.2+/-2.0 g, respectively, P<.05). Significantly less in vivo subsidence over the 8-week study period also was demonstrated in the experimental group compared to the control group (0.4+/-0.4 and 2.2+/-2.3 mm, respectively, P<.05). Angular motion during cyclic +/-1.5 Nm loading demonstrated significant differences between the 2 groups at time zero (2.67 degrees +/-1.02 degrees for the control group and 1.98 degrees +/-0.47 degrees for the experimental group, P<.05) and at 8 weeks (2.40 degrees +/-0.38 degrees for the control group and 1.74 degrees +/-0.55 degrees for the experimental group, P<.05). Histology showed little difference between the 2 groups, but there was a trend toward less inflammation in the experimental group.