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Tomasz Poboży

Hydrodilatation for frozen shoulder: an advantage over corticosteroid alone?

Autor:

Tomasz Poboży

Polish version: Hydrodylatacja barku zamrożonego — czy daje przewagę nad samym steroidem?

A randomized trial suggests that adding hydrodilatation to an intra-articular corticosteroid injection may accelerate functional and range-of-motion improvement in frozen shoulder. It used one ultrasound-guided 20 mL injection without intended capsular rupture. Only 50 patients entered the per-protocol analysis, however, and a recent systematic review of 9,951 patients reached more cautious conclusions.

Why this study matters

Intra-articular corticosteroids have an established role when pain and inflammation predominate. The additional value of mechanically distending the capsule is less certain. Kim and colleagues’ trial, published on 6 September 2026 in Journal of Orthopaedic Surgery and Research, evaluated a simple single-injection technique rather than repeated procedures, very large volumes or deliberate rupture.

Study design

This single-centre prospective superiority RCT masked patients and the follow-up assessor, but not the operator. Sixty-two patients were randomized; the final per-protocol analysis included 26 hydrodilatation patients and 24 controls.

Both groups received 40 mg triamcinolone and 4 mL of 1% lidocaine intra-articularly. Hydrodilatation added 15 mL saline for a total of 20 mL. A posterior ultrasound-guided approach aimed to stretch the capsule without intentionally rupturing it. Both groups received the same home stretching programme, at least 30 minutes daily, and analgesia.

Assessments were at 3 and 7 weeks and at 3 and 6 months. The primary endpoint was ASES improvement at 7 weeks; pain, Constant–Murley score, satisfaction and motion were also assessed.

Main results

  • ASES improvement at 7 weeks favoured hydrodilatation by 10.51 points (95% CI 4.12–16.89; P = 0.001).
  • At 6 months, forward elevation was 148.1° versus 138.8°, external rotation 74.6° versus 64.8°, and internal rotation 71.5° versus 58.1°.
  • ASES at 6 months was 88.5 versus 81.8 (P = 0.040); Constant–Murley was 63.8 versus 57.7 (P = 0.011).
  • The Constant score threshold for minimally important improvement was reached by 92.3% versus 50.0%.
  • Pain at 6 months did not differ significantly: VAS 0.7 versus 1.2 (P = 0.138).
  • No directly procedure-related complications were recorded.

Clinical interpretation for an orthopaedic surgeon

The signal emerged with one relatively modest 20 mL injection, without fluoroscopy or planned rupture. Any benefit therefore need not depend on extreme volumes or forceful capsular disruption. The absence of a pain difference at 6 months suggests a possible effect on the pace of motion and functional recovery rather than sustained analgesic superiority.

How this fits the wider evidence

A July 2026 British Journal of Sports Medicine review included 103 studies, 9,951 patients and 44 RCTs. Compared with corticosteroid alone, hydrodilatation improved external rotation at 12 weeks, but certainty was low and heterogeneity substantial. No convincing advantage was found for pain, SPADI, abduction or forward flexion. Across diverse techniques, the authors found no established clinically important superiority over steroid alone.

The new RCT does not invalidate that review. It suggests that a specific technique may merit separate study instead of treating all hydrodilatation variants as equivalent.

Limitations

  • Only 50 of 62 randomized patients entered the final analysis.
  • Per-protocol rather than intention-to-treat analysis may compromise randomization benefits.
  • Numerous secondary outcomes and time points lacked multiplicity adjustment and were considered exploratory.
  • The operator was unblinded, although follow-up assessment was independently masked.
  • A single centre and an Asian population limit generalisability.
  • Disease phase was not stratified.
  • Actual adherence to home exercises and medication was not monitored.
  • Recruitment occurred in 2013–2015, with retrospective ClinicalTrials.gov registration only in 2024.

Implications for practice

The trial suggests possible additional functional value from a single ultrasound-guided, capsule-preserving hydrodilatation. It supports studying a simple technique without assuming that large volumes or deliberate rupture are necessary. It does not justify routine treatment for every patient, demonstrate superiority to comprehensive conservative care or establish lasting benefits over many years. Optimal disease phase, volume and patient selection remain uncertain; this single positive study is insufficient to change the standard of care by itself.

References

  1. Konarski W, Poboży T, Hordowicz M, Poboży K, Domańska J. Current concepts of natural course and in management of frozen shoulder: A clinical overview. Orthop Rev (Pavia). 2020;12(4):8832. DOI: 10.4081/or.2020.8832.
  2. Kim YT, Hwang JT, Han SH, Hong MS, Lee JB. Simplified, single-shot, capsule-preserving hydrodilatation combined with corticosteroids versus isolated corticosteroid injection for adhesive capsulitis: a randomized controlled trial. J Orthop Surg Res. Published online 6 September 2026. DOI: 10.1186/s13018-026-07215-2.
  3. Rhim HC, Shin J, Olson G, et al. Hydrodilatation for adhesive capsulitis: a systematic review exploring efficacy and optimal technique. Br J Sports Med. Published online 29 July 2026. DOI: 10.1136/bjsports-2025-110539. PMID: 42527106.

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Content prepared by: Tomasz Poboży - orthopaedic surgeon.

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