Longitudinal Measurement of In-Vivo Tendon Function Over 17 Weeks Following Repair: Technique and Preliminary Results in a Canine Rotator Cuff Model

Rotator cuff tears are a common injury, affecting 30–40% of the population over age 60 and representing a tremendous source of pain and disability. Rotator cuff tears are often repaired surgically, but a significant percentage (perhaps 50% or more) of large cuff tears fail after surgery and result in long-term shoulder disability. The outcome of rotator cuff repair surgery is typically assessed by measuring muscle strength, joint range of motion, pain, and other subjective indicators of function. Although these types of measurements are used extensively, they provide only an indirect assessment of tendon function. We have recently developed new experimental techniques that allow us to use a biplane x-ray system to directly assess in-vivo tendon function. The purpose of this study was to assess the feasibility of using a biplane x-ray system to quantify changes in in-vivo tendon function following tendon repair in a canine rotator cuff model. We hypothesized that tendon function will improve over the healing period (as reflected by changes in measures of repair stiffness and contracture) and approach normal tendon function by 17 weeks.