In vivo fluoroscopic kinematography of dynamic radio-ulnar incongruence in dogs

Abstract

Aim of the study was to investigate dynamic radio-ulnar incongruence (dRUI) in the canine elbow joint comparing orthopedic healthy and dysplastic dogs in a prospective in vivo study design. In 6 orthopedic sound elbow joints (5 dogs, median age 17 months & mean body weight 27.9 kg) and 7 elbow joints with medial coronoid disease (6 dogs, median age 17.5 months & mean body weight 27.6 kg) 0.8 mm Ø tantalum beads were surgically implanted into radius, ulna and humerus for dynamic radiosteriometric analysis (RSA) using high-speed biplanar fluoroscopy with the dogs walking on a treadmill. dRUI, in the form of proximo-distal translation of the radius relative to the ulna, was measured for the first third of stance phase and compared between groups using unpaired t-testing. Healthy elbow joints exhibited a relative radio-ulnar translation of 0.7 mm (SD 0.31 mm), while dysplastic joints showed a translation of 0.5 mm (SD 0.30 mm). No significant difference between groups was detected (p = 0.2092, confidence interval -0.6 -0.2). Based on these findings dRUI is present in every canine elbow joint, as part of the physiological kinematic pattern. However, dysplastic elbow joints do not show an increased radio-ulnar translation, and therfore dRUI cannot be considered causative for medial coronoid disease.

CT evaluation of elbow congruity in dogs: radial incisure versus apical medial coronoid process fragmentation

“…However, fluoroscopic kinematography has recently refuted variance in axial dynamic congruity between normal and dysplastic elbows as an inciting cause of MCPD (Rohwedder et al . ); this group also documented significantly increased humeroulnar rotation in dysplastic elbows (Rohwedder et al . ).…”

“…Fluoroscopic kinematography studies have quantified dynamic change in humeroradioulnar articulation, revealing axial incongruity of similar magnitude in both normal and dysplastic elbows (Rohwedder et al . ), as well as increased rotational humeroulnar laxity in dysplastic elbows (Rohwedder et al . ).…”

“…Firstly, our study assessed joint space in the static, unloaded elbow and so dynamic variation of joint space measurements as a result of loading could not be evaluated. Fluoroscopic kinematography studies have quantified dynamic change in humeroradioulnar articulation, revealing axial incongruity of similar magnitude in both normal and dysplastic elbows (Rohwedder et al 2017), as well as increased rotational humeroulnar laxity in dysplastic elbows (Rohwedder et al 2018). Use of this technique to specifically objectify radioulnar articulation in dogs with radial incisure fragmentation would clarify if the mechanism of aberrant articulation we have Illustration (not to scale) of the predicted influence of reduced joint space in zone 2 between the radius and ulna on radioulnar articulation.…”

“…Multi-directional dynamic incongruities have also been postulated as potential mechanisms resulting in aberrant radioulnar articulation (Fitzpatrick & Yeadon 2009, Hulse et al 2010, Burton et al 2013. However, fluoroscopic kinematography has recently refuted variance in axial dynamic congruity between normal and dysplastic elbows as an inciting cause of MCPD (Rohwedder et al 2017); this group also documented significantly increased humeroulnar rotation in dysplastic elbows (Rohwedder et al 2018).…”

Radial torsion in dogs with medial compartment disease

“…In that regard, recent in vivo radiosteriometric studies comparing dogs with MCD with healthy controls have shown that, although dogs with MCD exhibit an increased rotational motion of the humerus, the same animals do not show a difference in dynamic radioulnar incongruence compared with healthy controls. 17,19 Furthermore, it has been demonstrated in human studies that torsional deformities of the antebrachium alter the rotational dynamics between the humerus, the radius, and the ulna. [20][21][22][23][24][25][26][27][28] To explore and verify these alternative mechanisms, the conditions affecting the motion between the humerus, the radius, and the ulna must be investigated further.…”