Short-Term Comparative Effectiveness of Intra-articular Corticosteroid Injection Versus Hydrostatic Distention in Idiopathic Frozen Shoulder: A Prospective Interventional Study

Background Idiopathic frozen shoulder (adhesive capsulitis) is a common and debilitating condition, characterized by progressive restriction of shoulder movement. Non-randomized interventional treatments, such as intra-articular corticosteroid injections and hydrostatic (hydrodilatation) distention, are commonly employed when conservative therapy fails. Objective The main objective of this study is to compare the short-term effectiveness of intra-articular corticosteroid injection versus hydrostatic distention, in terms of pain relief and functional improvement in patients with idiopathic frozen shoulder. Methods This prospective, single-center, comparative interventional study was conducted at Lady Reading Hospital, Peshawar, Pakistan. A total of 108 patients, aged 35-70 years, with frozen-phase idiopathic frozen shoulder (>3 months' duration), were assigned to two treatment groups using non-random, consecutive allocation: Group A (n = 54) received an intra-articular corticosteroid injection, and Group B (n = 54) underwent hydrostatic shoulder distention. Patients were assessed at baseline, 4 weeks, and 12 weeks using the Visual Analog Scale (VAS) for pain and the Shoulder Pain and Disability Index (SPADI) for function. Statistical analysis was performed using IBM SPSS Statistics for Windows, Version 25 (Released 2017; IBM Corp., Armonk, NY, USA). Results Both groups showed significant improvements in pain and function over time (p < 0.001). However, Group A demonstrated superior outcomes at 12 weeks in VAS (2.1 ± 0.9 vs. 2.6 ± 1.0; p = 0.027) and SPADI (28.6 ± 6.3 vs. 32.9 ± 6.5; p = 0.006). "Very satisfied" patients were more frequent in Group A (28 patients; 64.81%) than in Group B (35 patients; 51.85%). Conclusion Intra-articular corticosteroid injection appears to be more effective than hydrostatic shoulder distention in providing short-term pain relief, functional improvement, and higher patient satisfaction in idiopathic frozen shoulder. Further studies, with randomized designs and long-term follow-up, are warranted.