Isokinetic testing protocols for glenohumeral rotator strength assessment in unstable and surgically stabilized shoulders: A systematic review.

Abstract

Measuring shoulder rotator strength during rehabilitation of shoulder with instability provides objective information on muscle deficits and recovery progression. Adequate procedures for the assessment of shoulder rotator strength, as well as corresponding reference values, have yet to be established. This study aimed to determine which isokinetic procedure may be relevant to assess the glenohumeral rotator strength in shoulder with anterior instability and after stabilization surgery. The search strategy was (Shoulder AND (dislocation OR "anterior instability")) AND ("muscle contraction" OR isokinetic OR "muscle strength" OR torque) to consult PubMed, Web of Science, PeDro, Cochrane, SportDiscuss, and Embase from their inception to 2024 March 3^rd. The inclusion criteria were experimental studies having assessed the glenohumeral rotator muscles isokinetically in patients with shoulder anterior instability or after a shoulder anterior stabilization surgery. The exclusion criteria were patients with shoulder multidirectional instability or innate shoulder instability, or cadaveric population. Methodological quality was assessed using a self-developed scale designed to address isokinetic procedure setup specificities, not covered by existing validated tools. Among the 2015 identified studies, 47 were included involving 1602 patients (87% males; 27.3 ± 1.5 years). Of these, 806 patients were assessed with anterior shoulder instability, and 1332 were postoperatively; 28% following bone-block procedure and 59% after labral repair. The numerous combinations in parameter settings (body position, arm position, range of motion, contraction mode and angular velocity) allowed by isokinetic dynamometers, and in methods for outcome measures resulted in a multitude of heterogeneous experimental protocols, which are mainly reported with low methodological quality, thereby hindering data pooling for meta-analyses. and Relevance: This review reveals that reporting quality of shoulder isokinetic testing should be improved, and the scale for methodological quality assessment specifically developed may help standardize the description of isokinetic procedures in further studies. The comprehensive overview of glenohumeral rotator isokinetic strength may assist clinicians in comparing their patients' results, although such comparisons should be interpreted with caution. IV.