Assessment of radial torsion using computed tomography in dogs with and without antebrachial limb deformity.

OBJECTIVE: To evaluate the reliability of radial torsion assessment in dogs using computed tomography (CT). STUDY DESIGN: Cadaveric and retrospective observational clinical study. ANIMALS: Thoracic limbs (n = 40) from bilateral normal cadaveric canine specimens (10 pairs) and unilateral antebrachial angular limb deformity (ALD) dogs (10 uniapical and 10 biapical deformities). METHODS: Limbs were evaluated using CT. Frontal, sagittal, and axial plane (torsion) values were obtained using published guidelines and compared between groups and limbs. Radial torsion reliability was assessed among 3 observers using intraclass correlation coefficients (ICC). RESULTS: The mean (±SD) radial torsion of normal dogs was 3.6° ± 6.4° and contained a significant right to left limb variation of 2.6°. Mean radial torsion in uniapical ALD limbs (3.6° ± 18.7°) was not significantly different from biapical ALD limbs (8.9° ± 17.9°). There was a wide range of torsion values in normal and ALD limbs. The interobserver reliability was excellent (ICC > 0.8) for normal dogs, good (0.73) for uniapical, and excellent (0.89) for biapical ALD limbs. The intraobserver reliability was excellent (>0.8) for all groups. CONCLUSION: There was a small side-to-side variation of radial torsion in normal dogs. With directed training, torsion assessment using CT is reliable in dogs with and without antebrachial bone deformity.

Effect of the Proximal Abducting Ulnar Osteotomy on Intra-Articular Pressure Distribution and Contact Mechanics of Congruent and Incongruent Canine Elbows Ex Vivo.

OBJECTIVE: To determine the effects of the Proximal Abducting Ulnar Osteotomy (PAUL) on contact pressures of congruent and incongruent (short radius) canine elbows. STUDY DESIGN: Ex vivo biomechanical study. SAMPLE POPULATION: Unpaired normal cadaveric canine forelimbs (n=16). METHODS: A servohydraulic testing frame and thin-film sensors were utilized to measure intra-articular contact area (CA), mean contact pressure (mCP), and peak contact pressure (pCP) for medial and lateral elbow compartments. Percent contribution of the medial compartment relative to the whole (%Med) was also examined. Baseline data were collected in 9 congruent elbows and 7 incongruent elbows where the radius was shortened. Both sets of elbows were tested following ulnar osteotomy and sequential placement of 2 and 3 mm PAUL plates and paw repositioning (to account for any medial to lateral shift of transarticular forces). Paired t-tests compared sequential procedural steps. P<.05 was significant. RESULTS: For congruent elbows, the 2 mm PAUL plate decreased CA in both compartments compared to baseline; lateral pCP increased with subsequent paw repositioning. Induction of radio-ulnar incongruity decreased CA and increased mCP medially, decreased pCP laterally, and increased %MedCA and %MedmCP compared to baseline. Both PAUL plates decreased mCP and pCP medially, with no effect laterally. Paw repositioning had no effect. CONCLUSION: The PAUL procedure had no effect on medial compartment pressure in the congruent elbow. It may ameliorate increased medial compartment pressure in the incongruent elbow. This change does not result from a medial to lateral compartmental shift and deserves further investigation.

Bi-Oblique Dynamic Proximal Ulnar Osteotomy: Surgical Technique and Clinical Outcome in 86 Dogs.

OBJECTIVE: To describe the technique of bi-oblique dynamic proximal ulnar osteotomy (BODPUO) and report the clinical outcome in a series of dog with medial compartment disease and other developmental elbow diseases. STUDY DESIGN: Retrospective case series. ANIMALS: Dogs (n=86; 120 elbows) treated for elbow disease with BODPUO. METHODS: Medical records and diagnostic images were reviewed. Type and frequency of complications and treatment required were recorded. Force plate data were reported in dogs for which data had been recorded preoperatively and at follow-up. RESULTS: Mean (standard deviation) final follow-up was 23.4 (35.6) weeks. There were minor complications in 15 elbows (12%, 14 dogs). There were no major complications. The caudo-cranial and latero-medial mean osteotomy angles were 55° (7°) and 48° (10°), respectively. The most caudo-proximal point of the osteotomy was located at a mean of 39% (5%) of the total ulnar length from the olecranon. Sixty of 68 elbows (88%) were considered healed by 4 months postoperative based on radiographs. Subjective lameness scores were significantly decreased by final follow-up for all dogs. For dogs treated with BODPUO alone for medial compartment disease, peak vertical force was significantly higher at 6 months postoperative. CONCLUSION: Dogs with medial compartment disease undergoing BODPUO showed clinical improvement in the 6 month follow-up. No complications required surgical intervention.

Classification of Angular Limb Deformities Affecting the Canine Radius and Ulna Using the Center of Rotation of Angulation Method.

OBJECTIVE: To classify the type of angular deformity affecting the radius and ulna in canine limbs using the center of rotation of angulation methodology. STUDY DESIGN: Retrospective case series. ANIMALS: Dogs (n=71) diagnosed with thoracic limb lameness attributable to antebrachial angular limb deformities. METHODS: Medical records from 2006-2013 were searched and cases with orthogonal radiographs or computed tomographic scans of the affected antebrachium were included. Classification of the deformity in the frontal plane and the presence of sagittal plane angulation, torsion, and adjacent joint radiographic disease were determined and compared. RESULTS: Chondrodystrophic (n=26; 44 limbs) and non-chondrodystrophic (n=45; 62 limbs) dogs were included. Thirty-five uniapical and 71 biapical or multiapical deformities in the frontal plane were identified. The incidence of biapical deformities was statistically higher in chondrodystrophic compared to non-chondrodystrophic dogs (P=.02). When breeds were combined, biapical deformities were associated with a significantly higher incidence of adjacent radiographic joint disease (P=.049), more frequently affecting the elbow (P=.022). Overall, 82% of the 106 limbs had radiographic evidence of either elbow or carpal joint disease at the time of presentation. CONCLUSION: Biapical deformities are common in dogs with limb deformities, particularly chondrodystrophic dogs. Radiographic evidence of disease in adjacent joints should be evaluated in patients presenting for antebrachial deformities.

Assessment of low-cost teleradiology for grading elbow dysplasia.

Teleradiology involves the creation of a radiographic image that is then transmitted electronically. It has been shown that low-cost teleradiology has a high level of agreement when comparing the original radiograph to the digital image. However, there has been little investigation of the effect of digitization on the score allocated by a grading scheme. Radiographs of 60 canine elbows were selected, each in three projections (mediolateral flexed, mediolateral neutral, craniocaudal). Each radiograph was photographed at 3 megapixel (3 M) and 6 megapixel (6 M) resolution using a digital camera. The images were placed in groups (radiographs, 3 M and 6 M) and randomized. Each elbow was independently graded by a radiologist and an orthopedic surgeon using the BVA elbow scoring scheme, with the different image sets interpreted separately. Intra and interobserver agreement was compared using a kappa analysis. The radiologist had substantial intraobserver agreement for repeated grading of radiographs, and moderate agreement for the other intraobserver tests (3 M vs. radiographs, 6 M vs. radiographs, 3 vs. 6 M). The surgeon had moderate to substantial agreement for the intraobserver tests. There was reduced interobserver agreement for all image groups. These results suggest that low-cost teleradiology may only allow moderate accuracy when used for grading schemes, and this may affect its use for breed scoring schemes. However, there appears to be an inherent subjectivity present in the elbow-grading scheme, seen in both intra and interobserver analysis. Therefore, further study of teleradiology using a different scoring model (e.g., hip dysplasia) may be indicated.