Psychometric properties of pectoralis minor muscle length tests in individuals with and without rotator cuff-related shoulder pain: A COSMIN-based systematic review.

Background: Pectoralis minor length was associated with shoulder pain and functional limitations. Although various clinical tests assess pectoralis minor length in individuals with and without shoulder pain, their psychometrics properties have not been systematically explored.

Purpose: To provide a comprehensive overview of the measurement properties of tests used to assess pectoralis minor length in individuals with and without rotator cuff-related shoulder pain.

Study design: Systematic review with meta-analysis.

Methods: Four electronic databases were searched until February 2025. Studies assessing any pectoralis minor length tests measurement property in adults with and without rotator cuff-related shoulder pain were included. Two reviewers independently screened all studies and assessed the risk of bias using the COnsensus-based Standards for the selection of health Measurement Instruments (COSMIN) checklist. Subsequently, each measurement property of each pectoralis minor length test was classified as sufficient, insufficient, or inconsistent based on the COSMIN criteria for good measurement properties. A random-effects model was used in the meta-analysis.

Results: Three tests evaluating pectoralis minor length were identified from the 10 included studies. Although no test showed sufficient evidence for all measurement properties, the pectoralis minor length (origin-insertion distance) assessed in standing had the most properties evaluated. The test demonstrated the best measurement properties in individuals with and without shoulder pain, although measurement error and responsiveness still need to be determined. The pooled results indicated very good intra- (156 individuals without pain; ICC = 0.93, 95% CI: 0.89-0.95) and inter-rater (260 individuals without pain; ICC = 0.87, 95% CI: 0.66-0.95; 338 individuals with and without shoulder pain; ICC = 0.88, 95% CI: 0.75-0.95) reliability.

Conclusions: There is currently insufficient evidence to recommend any test for estimating pectoralis minor length. Thus, more research is needed, particularly regarding measurement error and responsiveness. Available tests should be used with caution in research and clinical practice.