Polar gap after cementless total hip replacement in dogs

Comparison of the distraction index and Norberg angle with radiographic grading of canine hip dysplasia

The Orthopedic Foundation for Animals (OFA) radiographic grading system stands as a well-established benchmark for categorizing hip dysplasia in canines. Although more objective techniques to quantify early hip laxity in young dogs, such as the Norberg angle (NA) and distraction index (DI), have been documented, there is a scarcity of published studies that directly compare these radiographic measures. The primary objectives of this prospective, analytical study were to assess and compare the NA and DI measures with OFA grades within a cohort of dogs. Thirty dogs (57 hip joints) were evaluated, with a mean age of 5.4 ± 2.9 years and a mean body weight of 34.3 ± 7.1 kg. The discriminative power of hip dysplasia for DI and NA used OFA as a reference were compared by multivariate discriminant analysis test. Using the DI (≤0.3) 12 joints were classified as normal, using NA (≥105°) 24 joints and using OFA (≤3) 29. When comparing the discriminant power of NA with OFA resulting similar (P = .8324) with correct classifications of 81% using cross validation, however, the discriminant power of dysplasia of the DI resulted significantly greater (P = .0034) than OFA with correct classifications of only 59% using cross-validation, consequently it was possible determined that of 29 patients with OFA ≤ 3, 20 had DI > 0.3. These findings demonstrated that phenotypic healthy dogs according to OFA grading can present passive hip joint laxity, as demonstrated by radiographic evaluation with distraction. Furthermore, DI can contribute to the screening of CHD when evaluated in conjunction with OFA grading.

Total hip replacement in dogs with contralateral pelvic limb amputation: A retrospective evaluation of 13 cases

OBJECTIVE

To report the clinical characteristics, surgical management, and medium-term outcomes of total hip replacement (THR) performed in dogs with previous contralateral pelvic limb amputation.

ANIMALS

Thirteen client-owned dogs.

STUDY DESIGN

Multi-institutional retrospective clinical study.

METHODS

Data recorded from medical records included signalment, indication for amputation and THR, and surgical complications. Implant positioning and complications were assessed on radiographs. Clinical outcomes were evaluated during follow-up examinations by one of the authors and through a mobility- and lifestyle-based questionnaire completed by owners.

RESULTS

All 13 dogs had satisfactory clinical results at follow-up a median of 3 months (range, 2-36) after THR. No postoperative luxation was recorded. Four dogs had minor complications that did not require additional treatment. The only major complication was one failure of osseointegration of a cementless acetabular cup, and it was successfully revised.

CONCLUSION

Total hip replacement resulted in satisfactory clinical results and acceptable morbidity in this population.

CLINICAL SIGNIFICANCE

Total hip replacement should be considered in dogs with severe coxofemoral joint disease and contralateral pelvic limb amputation.

Measurement of Acetabular Component Position in Total Hip Arthroplasty in Dogs: Comparison of a Radio-Opaque Cup Position Assessment Device Using Fluoroscopy with CT Assessment and Direct Measurement

OBJECTIVES

 The aim of this study was to compare measurements of angle of lateral opening (ALO) and version determined using a radioopaque cup position assessment device imaged with fluoroscopy to measurements obtained by CT and direct measurement in a cadaveric model. Our null hypothesis was that there would not be any difference in the angles measured by the techniques.

METHODS

 Six cadavers were implanted with BFX acetabular components. The CPAD was placed and images were obtained with fluoroscopy. Measurements were obtained from the radiopaque marker bars on the CPAD device, and version and ALO were calculated. The ALO and version were determined by CT and DM. Comparisons were made using a two-way analysis of variance and a generalized linear model procedure analysis.

RESULTS

 There were no significant differences between the measurements for ALO (p = 0.275) or version (p = 0.226). Correlation between methods was 0.948 and 0.951 for ALO and version, respectively. The mean difference (standard deviation [SD], and 95% confidence interval [CI]) for ALO were: CT versus CPAD 1.85 degrees (± 2.32 degrees [-2.99-3.31]), CT versus DM 1.96 degrees (± 1.99 degrees [-2.2-4.27]), CPAD versus DM1.74 degrees (±2.21 degrees [-1.13 and 5.24]). The mean difference (SD [CI]) for version was CT versus CPAD 2.86 degrees (±1.56 degrees [ -2.63-1.69]), CT versus DM 1.10 degrees (±1.42 degrees [-1.57-2.09]), CPAD versus DM 1.07 degrees (±0.76 degrees [0.13-2.09]).

CLINICAL RELEVANCE

 The results demonstrate that intraoperative imaging in cadaveric specimens with the CPAD is an accurate method to determine ALO and version of the acetabular component.