Feasibility and Preliminary Efficacy of Progressive Resistance Training as an Adjunct to Conventional Physiotherapy in Diabetic Adhesive Capsulitis: A Pilot Study

Abstract

Background: Adhesive capsulitis (AC) is a painful, progressively stiffening shoulder disorder that is more common in people with diabetes. Conventional physiotherapy centres on pain relief and mobilisation, and the added value of progressive resistance training (PRT) is uncertain. This pilot randomised controlled trial (RCT) assessed the feasibility of adding PRT to conventional physiotherapy in diabetic AC and explored its preliminary efficacy.

Methods: In this single-centre, assessor-blinded, two-arm parallel pilot RCT, 30 adults aged 40–65 years with type 2 diabetes and unilateral stage 1–2 AC were randomised 1:1, stratified by sex and baseline pain, to conventional physiotherapy plus PRT (Group A, n=15) or conventional physiotherapy alone (Group B, n=15). Both groups attended 18 supervised sessions (three per week for six weeks). Feasibility outcomes were retention, adherence, safety and acceptability. Secondary outcomes were pain (NPRS), goniometric active and passive range of motion (ROM), function (SPADI, DASH) and isometric strength (hand-held dynamometry), assessed at baseline, week 3 and week 6. Analyses followed the intention-to-treat principle (last observation carried forward) using baseline-adjusted ANCOVA, mixed-design ANOVA and Cohen’s d.

Results: Retention was 96.7% (29/30; 95% CI 83.3–99.4). Mean session attendance was 90.7% (16.3 of 18 sessions), 96.7% of participants attended at least 80% of sessions, and mean acceptability was 4.5 of 5. Nine mild, transient adverse events occurred (Group A 4/15; Group B 5/15); none was serious or glycaemic. At week 6, Group A showed greater improvement than Group B in SPADI total (adjusted difference −6.7, 95% CI −8.6 to −4.8 points; d=−1.24), DASH (−5.6, 95% CI −7.7 to −3.5 points), active flexion (7.2°, 95% CI 4.5 to 9.8), external rotation strength (0.89 kg, 95% CI 0.75 to 1.04; d=1.09) and all other ROM and strength measures. Pain during activity favoured Group A modestly (−0.5, 95% CI −0.9 to −0.1 points), whereas pain at rest did not differ clearly (−0.3, 95% CI −0.5 to 0.0 points). Group × Time interactions were significant for 16 of 17 outcomes.

Conclusion: Adding PRT to conventional physiotherapy was feasible, acceptable and, within the limits of a small pilot, apparently safe in adults with diabetic AC. Preliminary estimates favoured the addition of PRT for mobility, function and strength, although between-group differences in pain and function were small relative to published minimal clinically important differences. A definitive, adequately powered, multicentre RCT with longer follow-up is warranted.