A prospective study to evaluate factors associated with clinical and functional outcome of arthroscopic capsular release for primary adhesive capsulitis of the shoulder

INTRODUCTION

Shoulder periarthritis, also known as capsulitis, is characterized by excruciating pain and a growing restriction of mobility that has no apparent reason. For several months, the patient’s activities have often been progressively dominated by the symptoms, which also disrupt the sleep. Eventually, the shoulder stiffens, and the discomfort and spasms receded. Movement often returns gradually until the complete function is restored, either with a normal range of motion (ROM) or with a restriction that is so minor as not to result in a functional handicap.^[1]

Codman coined the term in 1934 as “Frozen Shoulder” (FS). Petri arthrite, scapulohumerale, and adhesive capsulitis are synonyms.^[2] Overall, the molecular mechanisms underlying this fibroproliferative tissue fibrosis are still poorly understood, despite the fact that immunobiological advancements in other diseases have helped to deconstruct its pathophysiology.^[3]

The incidence of idiopathic stiff shoulder is 2–5%, and men are more likely to be affected than women. The condition peaks between the ages of 40 and 60 years, with 20% of patients experiencing similar symptoms in the other shoulder and 14% experiencing bilateral simultaneous involvement.^[4,5]

The frequency of development of FS in individuals with diabetes can range from 10.8% to 30%.^[6] There is a tenfold greater frequency in poorly managed diabetes.^[7]

FS patients have a higher incidence (10.9%) and prevalence (27.2%) of hypothyroidism.^[8,9] Recent studies have reported that patients with thyropathy may have a 2.69-fold increased risk of developing FS.^[10] Other related disorders with FS are smoking, heart illness, Parkinson’s disease, stroke, neck and cardiac surgery, hyperlipidemia, and Dupuytren’s contracture.^[11,12]

Current modalities of treatment include, but are not limited to, conservative and surgical management. Options for treatment include individual or a combination of any of the following: oral corticosteroids, intra-articular injections of corticosteroids, intra-articular injections of hyaluronic acid, benign neglect, physiotherapy, deep heat modalities, manipulation under general anesthesia, hydrodilatation, and arthroscopic capsular release (ACR). However, the optimal course of treatment is still up for debate as the literature does not suggest a preferred method of treatment for this condition.^[4,13]

The aim of the study was to determine the factors associated with functional and clinical impact after ACR in patients with primary adhesive capsulitis.

MATERIALS AND METHODS

The study was conducted at a tertiary care hospital (Bangalore Medical College and Research Institute) after Institutional Ethics Committee approval. This study spanned between May 2023 and October 2024, and each participant was followed up for 3 months postoperatively.

Thirty-four patients aged between 30 and 70 years at the time of consent of primary adhesive capsulitis with restriction of all movements compared to the normal shoulder, both passive and active, especially in abduction, forward flexion, internal and external rotation (ER), and pain at night resulting in sleep disturbance were included in the study. Patients were excluded if there was evidence of glenohumeral joint arthritis, clinical evidence of neuromuscular disorder, secondary FS following an identifiable inciting event, recent trauma or fracture involving the shoulder girdle, the previous surgery of the affected shoulder, or magnetic resonance imaging (MRI) confirmed rotator cuff pathology. In addition, individuals unwilling to provide informed consent were excluded from the study.

RESULTS

All 34 participants were followed up for up to 3 months. The demographic characteristics of participants are presented in Table 1. The comorbidities [Table 2] and ANOVA test and paired t-test [Table 3] for the impact of comorbidities on outcomes are as follows.

No statistically significant difference in post-operative outcomes across different co-morbidity groups (p < 0.05). This suggests that co-morbidities have an impact on the pathogenesis of disease; however, they do not have an impact on the surgical outcome.

DISCUSSION

The significant observation that was studied was achieving near complete and painless ROM by anterior ACR in adhesive capsulitis of the shoulder in the sub-continent population. The arthroscopic release yielded better patient outcomes than conservative management, as shown by analysis of VAS, CMS, and ROM serially at various follow-up points, in both male and female patients free from confounding factors.

There was sustained and total pain alleviation in the arthroscopic release group by 4 weeks, and it persisted till 24 weeks, suggesting only mild discomfort. Our observation of persistent pain relief after arthroscopic release is in agreement with the published literature. The range of movements recorded at 3 months was comparable to other studies [Table 4].^[14-18]

The study demonstrated a significant reduction in the mean VAS score, from 7.79 ± 0.73 preoperatively to 1.47 ± 1.23 at 12 weeks postoperatively (p < 0.001). Scores consistently decreased over time: 4.35 ± 1.3 at 2 weeks, and 3.81 ± 1.38 at 6 weeks. In comparison, Anand et al.^[19] reported a decrease from 8.1 ± 0.8 to 0.9±0.3 (p < 0.001), Ebrahimzadeh et al.,^[20] reported a decrease from 9.3 ± 1.8 to 2.2 ± 0.8 (p < 0.05), while El Deriny et al.^[21] observed a reduction from 8.10 ± 0.8 to 1.10 ± 0.41 at 12 months (p < 0.01). These findings confirm the effectiveness of the intervention in significantly reducing pain.

Furthermore, the CMS showed significant improvement (p < 0.001), with pre-operative scores of 34.85 rising to 75.09 at 12 weeks. These findings align with El Deriny et al.^[21] who reported an increase in the Constant shoulder score from 32.77 ± 4.3 preoperatively to 81.67 ± 6.3 at 12 months (p < 0.05), and Yoo et al.^[22] observed a significant improvement in the Constant shoulder score from 38.0 ± 19.9 preoperatively to 79.6 ± 17.0 at final follow-up (p < 0.05). Similarly, Alazabi et al.^[23] reported an increase in the Constant score from 48.16 ± 6.31 preoperatively to 84.50 ± 11.96 at final follow-up (p < 0.05). Ebrahimzadeh et al.^[20] found a rise from 30.1 ± 9.3 preoperatively to 82.9 ± 12.5 at final follow-up (p < 0.001).

Early surgical intervention for pain relief is of paramount importance to push the patients to early and aggressive post-operative rehabilitation. Rizvi et al.^[24] found that both patients with a shorter duration of symptoms and those with a longer duration of symptoms experienced an improvement in ROM, patient-ranked stiffness, and strength postoperatively. In addition, those with shorter symptoms had greater improvements in IR, patient-ranked stiffness, and similar improvements in other motions after ACR for idiopathic adhesive capsulitis than those with a longer duration of symptoms. In this study, the patient presented with persistent pain and limited ROM at the 24-week follow-up.

In this study, the impact of age on outcome was noticed to negatively impact abduction of the shoulder (p = 0.001), which means less improvement in older patients. Similar observation regarding age was seen in Gómez-Muñoz et al.’s study.^[25] In this comparative study of patients over and under 50 years of age for functional results of circumferential capsular release in adhesive shoulder capsulitis, author concluded that “patient age did not affect outcomes significantly, with patients older than 50 years showing similar results to younger patients.”

Following anterior ACR, patients demonstrated significant gains in active and passive ROM for forward flexion, abduction, external, and IR. Every patient in the anterior arthroscopic release group achieved full ROM by the end of the study. The restoration of ROM after arthroscopic release corroborates previous studies.^[26,27]

Following ACR, we also examined the impact of underlying factors of sex or comorbidities on the functional impact and ROM improvement. Men and women showed similar improvement in performance, especially in ROM, which corroborates previous studies by Mardani-Kivi et al.^[26] In a study that also examined the underlying factors in manipulative treatment under anesthesia, Theodorides et al.,^[27] studied the underlying factors in ACR release under anesthesia and found that the functional scores of men were lower than those of women. No significant post-operative outcomes were noticed in participants who had comorbidities. Our data seem to confirm its possible pathogenetic role, but no significant association with postoperative outcomes was found, as recently suggested by De Virgilio-Salgado et al.^[28] Mertens et al.^[29] in a short-term multicenter observational study. Systematic reviews^[30,31] confirmed conflicting evidence regarding diabetes mellitus as a possible prognostic factor for influencing clinical outcomes in patients with FS. However, Bansiwal et al.^[32] in their study on 68 patients of adhesive capsulitis of the shoulder secondary to diabetes concluded that the improvement in ROM, decrease in pain, and functional outcome are better in diabetic patients with adhesive capsulitis undergoing ACR than conservative management.

There is a debate in the literature about the rate of arthroscopic release. Some consider the release of the coracohumeral ligament and the rotator interval to be sufficient,^[11] whereas some surgeons support the release of other joint structures, such as the inferior and posterior capsules, or advocate global capsular release.^[33] Sivasubramanian et al.^[34] in their systematic review and meta-analysis suggested that less extensive releases may result in better functional and pain scores. In addition to that, a posterior release offers increased early IR, which was not sustained over time, but provides early and sustained flexion improvements. A complete 360 release may not provide any further benefit. There were no significant differences in the complication rates among the three techniques.

In our study, we initially released the rotator interval, and as needed, the remnants of existing contracted area, either in the anterior and/or the posterior, were released. For future prospective studies that will be used to measure patient limitations in various shoulder movements, it might be possible to estimate the desired extent of capsular release before surgery.

The current available literature mentions the potential complications of this surgical procedure, which include, but are not limited to, infection, iatrogenic injuries causing chondral lesions, and axillary nerve damage, none of which were found in our study.

CONCLUSION

Anterior ACR is an effective and safe treatment modality for refractory primary adhesive capsulitis, leading to significant pain relief and functional improvement. Patient-specific prognostic factors aid in counseling for surgical intervention, resulting in optimization of surgical timing and expectations. Early surgical intervention and non-diabetic status were associated with superior outcomes.