Intra- and inter-observer reproducibility of shoulder laxity tests: Comparison of the drawer, modified drawer and load and shift tests.

Background: Conventional tests of shoulder laxity have been shown to have poor reliability due to the difficulty in palpating the subtle movements of the shoulder joint beneath the musculature. Modified drawer test that is performed while the soft tissues surrounding the shoulder are loosened has been proposed to facilitate glenohumeral joint movement and improve reliability. We hypothesised that the modified drawer test would have an improved intra- and inter-observer reproducibility in comparison to the drawer and load and shift tests. Correlation of shoulder laxity measured by these tests with generalized joint laxity was also assessed.

Methods: Forty healthy volunteers underwent bilateral shoulder examination in the clinic using the three tests for anterior and posterior laxity assessment by a consultant shoulder surgeon and a resident. The examination was repeated three months later by the same examiners in the same cohort. Intra- and inter- observer reproducibility was calculated using Kappa values. The correlation of shoulder with generalized joint laxity was also investigated.

Results: The modified drawer test showed significantly improved intra-observer reproducibility compared to the drawer test, but not to the load and shift (κ = 0.173, -0.042, and 0.009, respectively). There were no significant differences in the inter-observer reproducibility between the three tests (κ = 0.054, 0.055, and 0.056, respectively). Moderate correlation was noted between shoulder and generalized joint laxity when modified drawer test was used (r = 0.417).

Conclusions: The modified drawer test improves intra- but not inter- observer reproducibility compared to the drawer test. Shoulder laxity assessed by the modified test correlated to generalized joint laxity. The modified drawer test has an improved reproducibility and correlation to generalized joint laxity over the conventional tests.