Evaluation of the Radial Procurvatum Using the Center of Rotation of Angulation Methodology in Chondrodystrophic Dogs

Breed-typical front limb angular deformity is associated with clinical findings in three chondrodysplastic dog breeds

Angular front limb deformity (ALD) refers to an excessively curved limb conformation, which is seen in some chondrodysplastic dog breeds. Common characteristics of ALD include carpal valgus (VALG), front limb rotation (ROT), elbow incongruity, and lateral radial head subluxation. These may cause lameness and discomfort in affected dogs. The clinical impact and breed-specific characteristics of front limb conformation in chondrodysplastic breeds are unknown. This prospective and cross-sectional study aimed to investigate differences in front limb conformation between three chondrodysplastic breeds. We further evaluate whether front limb conformation is associated with clinical findings and limb function. We propose novel methods to classify findings in the interosseous space and to quantify lateral radial head subluxation. Data from a total of 224 front limbs from 112 dogs of three chondrodysplastic dog breeds (30 Standard Dachshunds, 29 Skye terriers, and 53 Glen of Imaal terriers) were included in the study. Front limb VALG and ROT were measured with a goniometer. From the radiographs, the elbow joint was graded for incongruity (INC), and the humeroradial angle (HRA) was measured to assess lateral radial subluxation. The association of front limb conformation with clinical signs and limb function was investigated using orthopedic examination, goniometric and kinetic measurements, and radiography. The breeds differed significantly in their front limb conformation. The Dachshund had the least ROT and the least radial head subluxation. The Skye terrier had the most VALG, the most radial head subluxation, and the largest prevalence of moderate and severe INC. The Glen of Imaal terrier had the most ROT. In addition, INC, ROT, VALG, and HRA were found to be independent of each other and were associated with several measurable clinical abnormalities and limb function such as pain, lameness, limited range of motion, and elbow joint osteoarthritis. This implies that VALG, ROT, and HRA could be used in addition to INC grading when choosing musculoskeletal characteristics of dogs suitable for breeding.

Assessment of normal radial joint orientation angles in nonchondrodystrophic small-breed dogs

OBJECTIVE

To establish reference intervals for radial joint orientation angles in the frontal and sagittal planes in small-breed dogs and to compare them to those previously reported for medium- and large-breed dogs.

ANIMALS

Antebrachii of 30 skeletally mature, nonchondrodystrophic small-breed dogs were evaluated radiographically.

PROCEDURES

Orthogonal radiographs were retrospectively assessed to determine the anatomic medial proximal radial angle, anatomic lateral distal radial angle, anatomic cranial proximal radial angle (aCrPRA), and anatomic caudal distal radial angle (aCdDRA). The frontal plane angle, θ angle, and procurvatum were also calculated. The radial joint orientation angles determined were compared to those previously reported for medium- and large-breed dogs via a 1-sample t test.

RESULTS

Mean and SD values for anatomic medial proximal radial angle, anatomic lateral distal radial angle, aCrPRA, and aCdDRA were 80.86 ± 2.86°, 85.60 ± 1.74°, 87.99 ± 2.79°, and 83.08 ± 3.14°, respectively. The mean and SDs for frontal plane angle, θ angle, and procurvatum were 4.75 ± 2.46°, 11.88 ± 1.76°, and 16.79 ± 4.13°, respectively. aCrPRA and aCdDRA were significantly different when compared to previously reported radial joint angles for medium- and large-breed dogs.

CLINICAL RELEVANCE

Reference intervals for small-breed dog radial joint orientation angles were reported. Significant differences were identified for some joint orientation angles when compared to medium- and large-breed dogs. This small-breed reference interval reported can be utilized in planning of radial angular limb deformity corrective surgery, particularly when dogs are bilaterally affected.