“COMPARATIVE EFFECTS OF EXERCISE AND NON-EXERCISE INTERVENTIONS ON ROTATOR CUFF FOOTPRINT INTEGRITY AT THE HUMERAL ATTACHMENT IN CONSERVATIVELY MANAGED PATIENTS”
Keywords:
Shoulder pain, rotator cuff,, external rotation lag sign, internal rotation lag sign, isometric strength,, clinically important improvement, randomized controlled trial.Abstract
Background: Pain and disability questionnaires do not directly assess the tendon-to-bone footprint, but functional
improvement has been used as a proxy for this. To our knowledge, no trial has compared structured exercise with a
non-exercise conservative intervention using the External and Internal Rotation Lag signs (ERLS, IRLS) as
imaging- independent clinical measures of footprint related function, together with objective strength testing.
Objective: To compare structured exercise and non-exercise conservative intervention on: Lag-sign performance,
Isometric external rotation and abduction strength deficit, Clinically important improvement (CII) after 6 months.
Methods: Two hundred patients with clinically diagnosed rotator cuff-related shoulder pain (RCRSP) were
randomly assigned to two groups: Group A (structured exercise, n=100), Group B (corticosteroid injection, ESWT
and education, n=100). Strength deficits of ERLS, IRLS and handheld-dynamometry were evaluated at baseline, 12
weeks, 3 months and 6 months. CII, a composite clinician's judgement in four outcome domains, was evaluated at
6 months.
Results: Group A had an advantage at the first post baseline assessment and this increased with each time point,
with no crossover. At 6 months, ERLS was 5.33° vs. 11.43° (difference −6.10°, 95% CI −7.06 to −5.14), IRLS 4.21°
vs. 8.23° (−4.02°, 95% CI −4.85 to −3.19), external rotation strength deficit 9.48% vs. 24.86% (−15.38, 95% CI
−17.16 to −13.60), and abduction strength deficit 11.69% vs. 27.06% (−15.37, 95% CI −17.25 to −13.49), all
p<0.001. The proportion of people who achieved CII was 75.0% in Group A and 55.0% in Group B (continuity
corrected χ² p=0.005; absolute difference 20 percentage points, 95% CI 7 to 33; number needed to treat ≈5).
Conclusions: Structured exercise resulted in improved and long-lasting lag-sign performance and isometric strength
compared with a non-exercise conservative package without showing an early crossover with the self-reported pain
and disability noted in the companion paper. Lag signs are clinical surrogates and the difference in strength part of
training specificity. The findings do not demonstrate tendon healing.
