SummaryGuidelines for assessing total hip arthroplasty (THA) radiographs for femoral implant stability have not been published; therefore, often the determination is subjective. The aim of this study was to identify radiographic criteria for veterinary clinicians to use when evaluating radiographs for femoral implant stability. Specific objectives were to: identify radiographic features associated with canine THA femoral implant loosening, evaluate whether technical recommendations for human femoral component implantation apply to dogs, and evaluate the effectiveness of radiographs for identifying canine THA implant loosening. Post-operative, follow-up, and post-mortem contact radiographs of canine implanted femora retrieved postmortem and mechanically tested for implant stability were evaluated. Based on the results, radiographic evaluation is not an effective means of assessing canine femoral implant stability; however, certain radiographic findings including implant retroversion, cement mantle cracks, or the appearance of cementmetal interface radiolucencies, may be indicative of implant loosening. It was also found that femoral implants completely surrounded by cement mantle of any thickness were less likely to loosen than those with an area lacking cement between the implant and bone. There was also a trend suggesting an association between inferior cement mantle quality and femoral implant loosening. In order to improve cement mantle quality and ensure that implants are completely surrounded by cement mantle, the use of modern cementing techniques is recommended.

SummaryFour dogs treated with triple pelvic osteotomies (TPOs) with loss of fixation secondary to screw loosening are reported. Two of the patients were revised with an additional ventral plate with successful outcomes. Revision TPO, with additional ventral plate fixation, was highly effective as a salvage technique for failed TPOs.

SummaryTriple pelvic osteotomies (IPO) were evaluated in 40 clinical cases. In 39 cases, these were young dogs with hip dysplasia; in one case, the TPO was used as a correction for a hip luxation. Unilateral TPOs were performed in twenty patients, twelve with traditional TPO (without additional ventral plate) and eight with additional ventral plate fixation. Bilateral TPOs were performed in twenty patients, thirteen with traditional TPO and seven with additional ventral plate. In traditional TPOs, evidence of implant failure occurred in 5 of 12 unilateral and 11 of 13 bilateral procedures. In TPOs with additional ventral plate fixation, minor screw loosening was detected in one of eight unilateral and zero of seven bilateral procedures. Statistically TPOs without additional ventral plate fixation had 9.2 times greater odds of screw loosening with significantly greater acetabular segment displacement (p < 0.01). Two traditional TPOs performed required additional surgery due to screw loosening. Other attempted additional stabilization techniques used with the TPO procedure included ilial body wiring, ischial body wiring, sacral screw purchase, and medial screw nuts, however these methods did not prevent loosening and migration. TPO with additional ventral plate fixation was highly effective at combating implant failure.