Evaluation of animal models and methods for assessing shoulder function after rotator cuff tear: A systematic review

Abstract

Background and objective Restoring the shoulder function is a crucial demand of patients with rotator cuff (RC) tears. Most preclinical studies only focused on biological and mechanical measurements. Functional assessment was less investigated in the preclinical studies. This study aims to review the literature of shoulder function in animal models for RC tears and evaluate the strengths and weaknesses of different shoulder functional assessments and animal models. Method A literature search for studies used RC tear animal models to evaluate changes in shoulder function was performed. We searched databases of PubMed, Embase, Web of Science, and Scopus from inception to September 2019. Animal species, functional parameters, injury and repair types, and study durations were summarised. Cluster analyses were then used to separate animal models with different levels of injury and timings of repair. The reliability and clinical relevance of the included assessments and animal models were then discussed. Results Fourteen animal studies that related to shoulder function in animal models of RC tears were reviewed. Five methods (gait analysis, passive range of motion test, open field test, staircase test, and running endurance test) to assess shoulder function were identified. Single or massive RC tendon tears and immediate or delayed RC repair models were found. We reported and discussed factors to be considered when researchers would select assessments and animal models for different study purposes. Conclusion Based on current evidences, gait analysis is the most appropriate method to assess changes in shoulder function of animal models of RC tears. More studies are required to further elucidate the reliability of passive range of motion measurement, open field test, staircase test, and running endurance test. Models that use massive tears and delayed repair better represent the clinical condition found in humans. The translational potential of this article Using more clinically relevant animal models and assessments for shoulder function identified in this review may help to investigate the value of preclinical researches and promote translation of preclinical interventions into clinical practices.