Alex J. Reiter (1), Hayden R. Schott (2), Ryan M. Castile (1), Paul C. Cannon (3), NecatHavlioglu (4), Aaron M. Chamberlain (5), Spencer P. Lake (1,2),
Journal of Orthopaedic Research, 39, Issue 9, September 2021: 2062-2072. DOI: 10.1002/jor.24918

Keywords

Elbow; Joint Contracture; Sex Differences; Biomechanics; Ectopic Calcification

Abstract

Posttraumatic joint contracture (PTJC) is a debilitating condition characterized by loss of joint motion following injury. Previous work in a rat model of elbow PTJC investigated disease etiology, progression, and recovery in only male animals; this study explored sex-based differences. Rat elbows were subjected to a unilateral anterior capsulotomy and lateral collateral ligament transection followed by 42 days of immobilization and 42 days of free mobilization. Grip strength and gait were collected throughout the free mobilization period while joint mechanical testing, microcomputed tomography and histological analysis were performed postmortem. Overall, few differences were seen between sexes in functional, mechanical, and morphological outcomes with PTJC being similarly debilitating in male and female animals. Functional measures of grip strength and gait showed that, while some baseline differences existed between sexes, traumatic injury produced similar deficits that remained significantly different long-term when compared to control animals. Similarly, male and female animals both had significant reductions in joint range of motion due to injury. Ectopic calcification (EC), which had not been previously evaluated in this injury model, was present in all limbs on the lateral side. Injury caused increased EC volume but did not alter mineral density regardless of sex. Furthermore, histological analysis of the anterior capsule showed minor differences between sexes for inflammation and thickness but not for other histological parameters. A quantitative understanding of sex-based differences associated with this injury model will help inform future therapeutics aimed at reducing or preventing elbow PTJC.

How Our Software Was Used

Dragonfly was used to apply a global linear attenuation coefficient threshold to CT scans.

Author Affiliation

(1) Department of Mechanical Engineering & Materials Science, Washington University in St. Louis, St. Louis, MO.
(2) Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO.
(3) Bayer Crop Science, St. Louis, MO.
(4) Department of Pathology, John Cochran VA Medical Center, St. Louis, MO.
(5) Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, MO.