Frozen shoulder, or adhesive capsulitis, is a common condition characterized by shoulder pain, stiffness, and progressive loss of range of motion (ROM). It often affects individuals aged 40 to 60 years and is typically more prevalent in women and individuals with diabetes mellitus. The condition is considered idiopathic when no clear underlying cause is identified. The pathophysiology of idiopathic frozen shoulder remains largely unclear, although inflammation and fibrosis of the glenohumeral joint capsule are believed to play a central role in its development. It is generally classified into three stages: the freezing stage, the frozen stage, and the thawing stage, each with distinct clinical features and varying degrees of pain and functional impairment [1].

The management of Idiopathic frozen shoulder includes both conservative and surgical approaches. Non-surgical treatments, such as physical therapy, corticosteroid injections, and oral analgesics, are often used in the early stages, while surgical interventions like arthroscopic capsular release are considered in refractory cases. Despite these options, the outcomes of conservative treatments remain variable, and many patients continue to experience functional limitations even after undergoing these therapies. Hydrodilation has emerged as a promising alternative for the management of frozen shoulder, where fluid is injected into the shoulder joint to stretch the capsule and improve mobility. This technique is minimally invasive and is associated with fewer complications compared to surgery [2].

Hydrodilation is believed to work by distending the joint capsule, disrupting adhesions, and providing pain relief. Several studies have shown promising results, demonstrating significant improvements in both pain scores and ROM following hydrodilation treatment. For example, a study by Chou et al. [3] reported significant reductions in pain and improved shoulder mobility in patients with frozen shoulder following hydrodilation. Similarly, a study by Nair et al. [4] found that hydrodilation resulted in a significant improvement in both function and pain relief in patients with adhesive capsulitis. However, while these results are encouraging, there remains a need for further research to establish the long-term efficacy and safety of hydrodilation as a standard treatment for idiopathic frozen shoulder.

The aim of this study is to evaluate the effectiveness of hydrodilation in treating idiopathic frozen shoulder by assessing pain relief, shoulder function, and ROM. This prospective observational study will provide valuable data to better understand the clinical benefits of hydrodilation and its potential role as a first-line treatment for this debilitating condition.

Study Design:

This was a prospective observational study conducted at Government Medical Baramullah,  from September  2023 to September  2024. After getting the approval by the Institutional Ethical committee, a profile of 50 patients aged 40 to 60 years with a clinical diagnosis of idiopathic frozen shoulder were included in the study. Patients were selected based on the following inclusion criteria:

• Diagnosed with idiopathic frozen shoulder, confirmed through clinical examination and radiological imaging.
• A history of pain and restricted range of motion for at least 6 weeks.
• No prior treatment with hydrodilation or surgical interventions.

Exclusion criteria included:

History of shoulder trauma, systemic inflammatory conditions (e.g., rheumatoid arthritis), or neurological disorders affecting shoulder mobility.

• Previous shoulder surgery or ongoing systemic steroid treatment.

Intervention: All patients received hydrodilation therapy. The procedure was performed under fluoroscopic guidance to ensure accurate placement of the needle. A mixture of 30 mL of saline solution and 10 mL of 1% lidocaine was injected into the glenohumeral joint capsule to create distension. The procedure was completed in a single session, and patients were instructed to follow up for reassessment at 1, 3, and 6 months post-treatment.

Outcome Measures:

• Pain Assessment: The Visual Analog Scale (VAS) was used to measure pain severity before and after the treatment at each follow-up visit. The VAS is a 10-point scale where 0 indicates no pain and 10 represents the worst possible pain.
• Shoulder Function: The Constant-Murley Shoulder Score (CMS) was used to assess shoulder function, including pain, activity level, range of motion, and strength. The CMS score was recorded at baseline and at each follow-up visit.
• Range of Motion (ROM): Active range of motion in shoulder flexion, abduction, and external rotation was measured using a goniometer.

Statistical Analysis:

Data were analyzed using the SPSS statistical software (version 26). Descriptive statistics, including means, standard deviations, and percentages, were used to summarize patient characteristics and outcome measures. Paired t-tests were used to compare pre-treatment and post-treatment values for VAS, CMS, and ROM at 1, 3, and 6 months. A p-value of <0.05 was considered statistically significant.

A total of 50 patients were enrolled in this study, with an average age of 52.4 ± 6.5 years. Among them, 30 were female (60%) and 20 were male (40%). The majority of patients (80%) were diagnosed with the freezing stage of frozen shoulder, while 20% were in the frozen stage. No significant demographic differences were observed between the groups [Table 1].

Table 1:  Demographic Characteristics of the Study Population

The Visual Analog Scale (VAS) scores significantly decreased after hydrodilation. The mean VAS score at baseline was 8.2 ± 1.0. At 1 month, the VAS score decreased to 5.1 ± 1.2 (p < 0.001). At 3 months, it further reduced to 3.2 ± 1.1 (p < 0.001), and by 6 months, the mean VAS score was 2.1 ± 1.4 (p < 0.001). The primary outcome measures—pain reduction, shoulder function improvement, and increase in range of motion (ROM)—were assessed at baseline, 1 month, 3 months, and 6 months post-treatment [Table 2].

Table 2: Changes in Pain (VAS Score) Over Time

The Constant-Murley Shoulder Score (CMS) improved significantly over time. The baseline CMS score was 32.5 ± 5.2. At 1 month, it improved to 45.3 ± 6.8 (p < 0.001), and at 3 months, it reached 55.7 ± 7.1 (p < 0.001). By 6 months, the average CMS score was 61.8 ± 6.7, representing a significant improvement in overall shoulder function (p < 0.001) [Table 3].

Table 3: Changes in Shoulder Function (CMS Score) Over Time

Range of motion improved in all directions. The average flexion increased by 30°, from 90° ± 12° at baseline to 120° ± 15° at 6 months (p < 0.05). Abduction improved by 28°, from 85° ± 10° to 113° ± 14° (p < 0.05), and external rotation increased by 25°, from 30° ± 8° to 55° ± 9° (p < 0.05) [Table 4].

Table 4: Changes in Range of Motion (Flexion, Abduction, External Rotation) Over Time

The overall complication rate was relatively low, with 34 (68%) of patients reporting no complications following the procedure. Among the complications, mild swelling was the most commonly reported, occurring in 4 patients (8%), while post-procedure pain was experienced by 7 patients (14%). Joint stiffness was reported by 5 patients (10%), but no infections were observed in any of the patients treated [Table 5].

Table 5: Complication Rates Following Hydrodilation Treatment

All changes in VAS, CMS, and ROM were statistically significant (p < 0.05), indicating that hydrodilation led to marked improvements in pain, shoulder function, and ROM at the 1, 3, and 6-month follow-up periods. The largest improvements were observed within the first 3 months, with continued but slower progress up to 6 months [Fig 1].

Fig 1.

Fig a, before injecting dye.       Fig b, after injecting dye

This prospective observational study aimed to evaluate the effect of hydrodilation in patients with idiopathic frozen shoulder. The results demonstrated significant improvements in pain reduction, shoulder function, and range of motion (ROM) following hydrodilation treatment. Pain, as measured by the Visual Analog Scale (VAS), significantly decreased from a baseline score of 8.2 to 2.1 at 6 months. This finding aligns with previous studies showing that hydrodilation is effective in alleviating pain in patients with adhesive capsulitis of the shoulder [5, 7]. Similarly, the Constant-Murley Shoulder Score (CMS) showed significant improvement, indicating enhanced shoulder function. This improvement was consistent with findings from other studies that have demonstrated positive outcomes in shoulder function following hydrodilation [6, 8].

The increase in ROM across all planes—flexion, abduction, and external rotation—further supports the efficacy of hydrodilation in improving shoulder mobility. These findings corroborate earlier studies, where patients reported enhanced mobility after hydrodilation, with the most significant gains observed in the first 3 months post-procedure [9]. The marked improvement in flexion (30°), abduction (28°), and external rotation (25°) is noteworthy, as frozen shoulder is often characterized by severe limitations in these movements. The results from this study suggest that hydrodilation helps break the pathological adhesions in the shoulder joint capsule, thereby improving joint mobility and reducing pain.

One of the strengths of this study is the low rate of complications associated with hydrodilation. In our cohort, 68% of patients experienced no complications, and the most common adverse events were mild swelling and post-procedure pain. These findings are consistent with other research reporting minimal adverse effects associated with hydrodilation [10]. There were no instances of infection, further reinforcing the safety of the procedure. While mild swelling and temporary pain were common, these symptoms were generally self-limiting and resolved within a few days.

The improvement in symptoms and function observed in this study is in line with existing literature, which suggests that hydrodilation is a safe and effective treatment for idiopathic frozen shoulder. Previous studies have reported favorable outcomes in terms of pain relief and ROM, with hydrodilation being particularly beneficial for patients in the freezing stage of frozen shoulder [5, 6]. Furthermore, the data suggest that the benefits of hydrodilation persist for at least 6 months post-treatment, with continued improvements in shoulder function.

However, this study is not without limitations. The sample size of 50 patients is relatively small, and the observational nature of the study means that causality cannot be definitively established. Additionally, the lack of a control group limits the ability to compare the effects of hydrodilation against other treatment modalities, such as corticosteroid injections or physical therapy. Future studies with larger sample sizes and randomized controlled trials are necessary to confirm these findings and further explore the long-term effects of hydrodilation.

In this prospective observational study, hydrodilation was found to be a highly effective and safe treatment for patients with idiopathic frozen shoulder. The procedure significantly improved pain relief, shoulder function, and range of motion (ROM), with sustained benefits observed over a 6-month period. The complication rate was low, with only mild swelling and post-procedure pain reported in a small number of cases, confirming the safety profile of hydrodilation. These findings support the growing body of evidence suggesting that hydrodilation is a promising non-invasive option for the management of adhesive capsulitis, particularly for patients in the freezing stage of the condition.

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