Evaluation of Risk Factors for Luxation After Total Hip Replacement in Dogs

Authors

  • Jonathan Dyce MA, VetMB, DSAO, MRCVS, ERIK,

    1. From the College of Veterinary Medicine, and Biostatistics Program, University Medical Center, The Ohio State University, Colum-bus, OH.
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  • Erik R. Wisner DVM, Diplomate, ACVR,

    1. From the College of Veterinary Medicine, and Biostatistics Program, University Medical Center, The Ohio State University, Colum-bus, OH.
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  • Qiang Wang MS,

    1. From the College of Veterinary Medicine, and Biostatistics Program, University Medical Center, The Ohio State University, Colum-bus, OH.
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  • Marvin L. Olmstead DVM, MS, Diplomate ACVS

    1. From the College of Veterinary Medicine, and Biostatistics Program, University Medical Center, The Ohio State University, Colum-bus, OH.
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  • Address reprint requests to Jonathan Dyce, College of Veterinary Medicine, Veterinary Teaching Hospital, The Ohio State University, 601 Vernon L Tharp St, Columbus, OH 43210–1089.

Abstract

Objective— To identify risk factors for luxation after canine total hip replacement (THR).

Study design— Retrospective study.

Sample population— 256 client-owned dogs that underwent THR.

Methods— Patient data surveyed included signalment, body weight, diagnosis, prior hip surgery, implant size, intraoperative complications, and angle of lateral opening of the acetabular component.

Results— Postoperative complications were recorded in 20 cases (7.8%). The most common complication was dorsal luxation which occurred in 12 dogs (4.7%). The interval between joint replacement and luxation ranged from 1 to 116 days (mean, 44 days). In 1 case, luxation was attributable to failure of the repair of an intraoperative fracture of the greater trochanter. Excluding this case, the mean angle of lateral opening in those dogs that sustained luxation was 62° (range, 46°-75°). The mean angle of lateral opening overall was 48° (range, 18°-76°). The angle of lateral opening was the only factor that had a statistically significant effect on whether luxation occurred (P= .035). Acetabular revision, performed primarily to reduce the angle of lateral opening, was performed in 8 dogs and successfully prevented subsequent luxation.

Conclusion— Luxation of the prosthesis is substantially under the control of the surgeon. It is recommended that the acetabular cup be inserted at an angle of lateral opening of 35° to 45°. In those cases of THR luxation in which an inappropriate angle of lateral opening is identified, acetabular revision arthroplasty generally results in a good clinical outcome.

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