Effect of ulnar ostectomy on intra-articular pressure mapping and contact mechanics of the congruent and incongruent canine elbow ex vivo.
OBJECTIVE
To determine (1) the effect of elbow incongruity on contact mechanics and (2) the effect of treatment of this incongruity with 1 of 2 ulnar ostectomies in the canine elbow.


METHODS
Ex vivo biomechanical study.


METHODS
Unpaired cadaveric canine forelimbs (n = 17).


METHODS
In a servohydraulic testing frame, thin-film pressure sensors were placed into the lateral and medial compartments of the elbow. Specimens were tested in 135° of elbow joint flexion at 200 N of cyclic axial force, followed by a 20 seconds hold. Intra-articular contact area (CA), mean contact pressure (mCP) and peak contact pressure (pCP) were measured in each compartment. After radial shortening, testing was repeated and limbs randomized into proximal ulnar ostectomy with IM pin (PUO) or sequential distal ulnar ostectomy (DUO), interosseous ligament release (DUO-L), and ulnar attachment of the abductor pollicis longus muscle and interosseous membrane release (DUO-ML). Paired t-tests were used to compare each treatment to baseline values. Differences between treatment groups were evaluated with a mixed model with random effect to adjust for the clustering of limbs within dog. P < .05 was considered significant.


RESULTS
Radial shortening resulted in shift of mCP and pCP from the lateral to the medial compartment. The PUO group resulted in normalization of medial compartment mCP and decrease of pCP, whereas in the DUO group return to baseline was achieved only after DUO-ML.


CONCLUSIONS
PUO is effective in unloading medial compartment pCP in an incongruent joint.
Department of Clinical Sciences, Cornell University, Ithaca, New York.
Ursula
U
Krotscheck
Sarah
S
Kalafut
Gregory
G
Meloni
Margret S
MS
Thompson
Rory J
RJ
Todhunter
Hussni O
HO
Mohammed
Marjolein C H
MC
van der Meulen
D000818:Animals; D004283:Dog Diseases / Q000473:pathology / Q000601:surgery*; D004285:Dogs; D005552:Forelimb / Q000473:pathology*; D007592:Joint Diseases / Q000473:pathology / Q000601:surgery / Q000662:veterinary*; D007596:Joints / Q000473:pathology*