Can handheld dynamometry predict rotator cuff tear size? A study in 2100 consecutive patients.

Area of Science:

• Orthopedic Surgery
• Musculoskeletal Biomechanics

Background:

• Rotator cuff tears are a common shoulder pathology requiring surgical intervention.
• Accurate assessment of tear size is crucial for surgical planning and prognosis.

Purpose of the Study:

• To evaluate the predictive capability of handheld dynamometry measurements for rotator cuff tear size.
• To determine if dynamometry can differentiate between partial-thickness and full-thickness tears.

Main Methods:

• Retrospective analysis of handheld dynamometer readings from 2100 patients undergoing shoulder surgery.
• Stratification of patients into tear groups (partial vs. full-thickness) and by tear size.
• Correlation analysis between strength measurements and tear characteristics.

Main Results:

• Patients with partial-thickness tears demonstrated greater strength in internal rotation, external rotation, and supraspinatus.
• Lower supraspinatus strength was associated with the presence of rotator cuff tears.
• Larger tear sizes correlated with reduced external rotation and supraspinatus strength.
• A predictive model showed modest correlation (r = 0.25) with actual tear size.

Conclusions:

• Handheld dynamometry shows limited reliability in predicting rotator cuff tear size.
• Dynamometry can predict the presence of a tear but overestimates tears in intact shoulders (29% specificity).
• Further research may explore refined dynamometry protocols or complementary diagnostic tools.