Anti-Inflammatory Treatment and Active Physical Therapy Have Differing Effects on Functional, Mechanical, and Histological Properties in a Rat Model of Post-Traumatic Elbow Contracture

Abstract

Abstract. Post-traumatic joint contracture (PTJC) frequently occurs in the elbow after injury, decreasing range of motion (ROM) and causing dysfunction. Physical therapy improves ROM but does not address underlying inflammation and fibrosis. Combining physical exercise with biological treatment has shown positive results in other physiological systems. Objective: evaluate whether active physical therapy and anti-inflammatory drug treatment, alone or in combination, could preserve mechanics and function in a rat model of PTJC. Elbow PTJC was surgically induced in rats followed by joint immobilization (IM). Animals received either anti-inflammatory drug (celecoxib or CEL) treatment, active physical therapy (wheel activity or WA), or both (CELWA). An untreated cage activity (CA) group served as control. Functional evaluation, joint mechanical testing, and histological analysis were used to compare groups. All treatments improved gait parameters compared to CA, with WA showing the most improvements. WA also showed improved forelimb strength ratio compared to CA, but this difference was not significant. Postmortem joint mechanics were slightly improved in WA and CEL and most improved in CELWA compared to CA. Histological analysis showed that all treatments improved fibrosis, adhesions, vascularity, and thickness of capsule tissue to varying degrees. Cartilage surfaces showed improved structure and cellularity for all treatments. PTJC involves multiple tissues and cell types, and thus a multitreatment approach will likely be needed to address all underlying causes: biological modulation of the inflammatory response combined with physical disruption of fibrotic tissue may show more efficacy than either treatment alone.