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Current treatment options for frozen shoulder are not established as the standard-of-care. The condition may resolve without intervention, but symptoms may persist despite treatment. Frozen shoulder is associated with inflammatory reactions that can reduce quality of life. Our aim was to determine whether triamcinolone acetonide, an immunosuppressive steroid, improved functional recovery when administered after arthroscopic capsular release for frozen shoulder.
We selected participants using inclusion and exclusion criteria designed to reduce the impact of potential confounding factors. Under general anesthesia, we performed arthroscopic capsular release followed by manipulation to ensure adequate range of motion and wound closure. In the steroid treatment group, we injected triamcinolone acetonide into the glenohumeral joint immediately prior to wound closure. The follow-up period was six months. To determine the efficacy of steroids in improving overall post-procedure functional recovery, we statistically analyzed data from various qualitative and quantitative variables.
Our study consisted of 22 patients with frozen shoulder, 11 in each of the surgery-only and surgery with steroid injection groups. There were no significant differences between groups in the demographic data of the study participants. We observed significantly greater improvements in abduction range of motion in the steroid treatment group than in the surgery-only group, at three and six months post-treatment. Improvements in other movement parameters were similar in both groups. The steroid-treated group had a significantly higher numerical rating scale score for night pain at three months post-treatment than the surgery-only group.
Postoperative steroid treatment led to early recovery of the abduction range of motion in patients with frozen shoulder. Hence, the current standard-of-care protocol for frozen shoulder and other similar conditions requiring surgical intervention should include this type of treatment. Therapeutic reduction in the inflammatory response following arthroscopic capsular release can significantly improve prognosis and quality of life.
Frozen shoulder is a common clinical disorder of the shoulder joint; however, there is no established single best treatment. It traditionally progresses through three clinical phases: freezing, frozen, and thawing. Although there have been reports of it resolving spontaneously, some symptoms persist even after several years of conservative treatment.
Many believe that synovial hyperplasia and overexpression of inflammatory cytokines in the glenohumeral joint causes frozen shoulder. However, it can also occur when the shoulder has been immobilized for a long period and when chronic inflammation leads to joint capsule fibrosis.
According to the guidelines of the Upper Extremity Committee of the International Society of Arthroscopy, Knee Surgery, and Orthopedic Sports Medicine (ISAKOS), the range of motion (ROM) in frozen shoulder is as follows: flexion, less than 100°; external rotation, less than 10°; and internal rotation, less than that of the fifth lumbar vertebral level.
In cases with residual symptoms after conservative treatment, early surgery can facilitate the resumption of daily activities. Previous reports indicate that ACR can rapidly improve ROM and provide pain relief and long-term maintenance of beneficial results.
the post-treatment effects of this steroid remain unclear.
The purpose of this study was to investigate the early postoperative effects of steroid injection after ACR for frozen shoulder. We used triamcinolone acetonide (TA) instead of mPSL because it has a lower risk of osteonecrosis.
Considering its usefulness in conservative treatment of frozen shoulder, we hypothesized that steroid injection would result in greater improvement in ROM. Therefore, we compared the efficacy of ACR with and without TA, three and six months after treatment.
MATERIALS AND METHODS
This was a retrospective study, and we included all cases that met the inclusion criteria. The study period was from July 2017 to October 2020, with ACR alone for patients up to October 2018, and along with TA for patients in later periods. This was an open-label study and there was no randomization or blinding.
The inclusion criteria were as follows: (1) a case of ACR for idiopathic frozen shoulder diagnosed according to the ROM guidelines of the ISAKOS Upper Extremity Committee
; (2) postoperative follow-up for six months; and (3) use of an interscalene brachial plexus block (ISBPB) to control perioperative pain and align pain baselines. The exclusion criteria were as follows: (1) comorbidities, such as diabetes mellitus, that can separately affect joint function; (2) rotator cuff tears that require repair, (3) traumatic injuries, such as a proximal humeral fracture and a capsular tear; (4) previous ipsilateral shoulder surgery; and (5) calcific tendonitis of the shoulder.
We conducted this retrospective observational study using the opt-out method on our hospital website and performed all procedures in compliance with regulations and guidelines. The institutional review board of Gunma University Hospital (Identification number HS2021-168) approved this study.
We only used ACR in this study. All patients underwent surgery under general anesthesia and we performed continuous ISBPB before general anesthesia. For safety reasons, patients were awake during ISBPB and placed in a beach chair position using an arm positioner.
After confirmation of ROM under anesthesia, we completed sterilization and draping, created a posterior portal, and inserted an arthroscope into the glenohumeral joint. Simultaneously, we inserted a needle from the lateral side of the coracoid process toward the rotator interval to confirm the location and created an anterior portal in the rotator interval above the subscapularis tendon. To perform capsular release, we first dissected the rotator interval behind the long head of the biceps and the superior aspect of the capsule and then created an anteroinferior to posteroinferior incision in the capsule.
Where the inferior aspect of the capsule was inaccessible due to limited reach, we used a posteroinferior approach at an appropriate position on the lateral side of the posterior portal. We then inserted the arthroscope through the anterior portal, followed by dissection from the posterosuperior to the posterior surfaces. Following capsular release, we performed manipulation to confirm sufficient ROM.
The evaluator was not necessarily the surgeon; however, the same evaluator consistently performed the postoperative evaluation. Because this was an open-label study, we did not blind the evaluator to the treatment type.
Steroid injection into the glenohumeral joint
In ACR with TA, we injected 40 mg of TA into the glenohumeral joint while viewing through the posterior portal. Immediately thereafter, we quickly closed the wounds with subcutaneous sutures and sterile Dermabond strip skin closure (Ethicon, Inc., Raritan, NJ, USA) to avoid TA leakage.
We used the same protocol for postoperative therapy in all patients. For perioperative pain control, we used ISBPB (a mixture of 200 mL of 0.25% levobupivacaine and 100 mL of continuous saline administered at 6 mL/h) for intensive rehabilitation until the seventh postoperative day, and then discharged the patient. Patients completed ROM training for both active and passive movements from the first postoperative day without restriction, based on pain.
To detect early postoperative changes, an orthopedic surgeon examined patients before surgery at the outpatient visit and at three and six months after surgery. The evaluation elements included sex of the patient, affected side, age at surgery, surgery time, numerical rating scale (NRS) score for pain, passive ROM of the affected shoulder, and clinical scores.
We measured shoulder flexion, abduction, external rotation, and internal rotation to determine ROM. For internal rotation, we determined the highest vertebral spinous process that the patient could reach with the thumb by placing the dorsal surface of the hand on the back and moving the thumb cranially. For statistical analysis, we scored internal rotation as follows: 1–12 for the first to twelfth thoracic vertebra, 13–17 for the first to fifth lumbar vertebra, 18 for the sacrum, 19 for the buttocks, and 20 for the thigh. Using the NRS, we evaluated pain at rest, during motion, and at night. Clinical scores included the Constant score and the American Shoulder and Elbow Surgeons (ASES) score.
We compared preoperative demographics between the ACR and ACR+TA groups using Fisher’s exact probability test for categorical variables and the unpaired t-test for continuous variables. Next, we calculated change by subtracting the preoperative (baseline) value from the postoperative value at three or six months and compared between groups using an unpaired t-test. For within-group comparisons between time points (perioperative, three months, and six months), we performed a one-way analysis of variance and a post hoc Bonferroni correction. Finally, we conducted a post hoc power analysis. We completed the statistical analysis using IBM SPSS Statistics version 25 software (IBM Corp., Armonk, NY, USA), and statistical significance was set at P < 0.05. Additionally, we used G*Power version 3.1 (Heinrich Heine Universität, Düsseldorf, Germany) to conduct a post hoc analysis to confirm the power of this study.
We enrolled 44 subjects undergoing ACR for frozen shoulder at our hospital in the study. Based on the inclusion and exclusion criteria, we included 22 patients and excluded 22 patients. Eleven patients who underwent surgery by October 2018 were assigned to the ACR group (ACR alone; mean age 54.6 years; three males and eight females), and 11 patients who underwent surgery after that date were assigned to the TA group (ACR+TA; mean age 54.1 years; four males and seven females) (Figure 1). A post hoc analysis showed that the power was 80.3%.
Table I shows patient demographic data. There were no significant differences in sex, affected side, age at surgery, pain NRS score, shoulder ROM, or clinical scores between the ACR and ACR+TA groups at baseline. The mean operation time did not differ either (ACR group: 49.5 ± 19.7 min, ACR+TA group: 59.6 ± 21.5 min, P = 0.261).
Table IDemographic data and preoperative scores
Affected side (Right/Left)
Continuous (mean ± SEM)
54.6 ± 10.8
54.1 ± 7.3
Pain NRS score
1.1 ± 0.4
1.9 ± 0.4
5.6 ± 0.7
6.3 ± 0.6
5.1 ± 0.8
4.1 ± 0.8
Passive ROM (degree)
103.2 ± 15.7
107.3 ± 19.5
94.6 ± 18.0
90.5 ± 17.4
8.2 ± 5.1
15.0 ± 20.2
16.5 ± 2.9
15.7 ± 4.0
33.4 ± 2.8
37.9 ± 13.8
39.5 ± 18.3
52.3 ± 20.6
ACR: arthroscopic capsular release
TA: triamcinolone acetonide (40 mg)
SEM: standard error of the mean
NRS: numerical rating scale
ROM: range of motion
Internal rotation: 1 for the first thoracic vertebra, 13 for the first lumbar vertebra
We compared values at the three time points (preoperative and three and six months postoperatively for each group). The P-values indicate that ROM (flexion, abduction, and external and internal rotation) and clinical scores (Constant and ASES) were significantly higher at three and six months after surgery than before surgery, in both the ACR+TA and ACR groups (Table II). Compared to baseline, we observed significant improvements for all NRS scores at three and six months in the ACR group, for the motion NRS score at three months, and for the resting and night NRS scores at six months in the ACR+TA group. There was no significant improvement in ROM, NRS scores, or clinical scores from three to six months in either group.
Table IIComparison of values before surgery and at three and six months after surgery for each group
We compared the groups for improvement from baseline at three and six months after treatment. The improvement in ROM abduction was significantly greater in the ACR+TA group than in the ACR group at three (P = 0.03) and six months (P = 0.02) (Table III) (Figure 2). Improvement in night pain was significantly greater in the ACR group than in the ACR+TA group at three months (P = 0.045) (Figure 3). There were no significant differences in clinical scores, flexion, external or internal rotation ROM, or pain at rest or during motion between the two groups at any time point. No adverse events occurred in either group.
Table IIIComparison between the groups at three and six months post-treatment: Improvement relative to baseline
The main finding of this study was that the change in abduction ROM was significantly greater at three and six months after ACR+TA. To our knowledge, this is the first study to investigate and demonstrate the benefits of intra-articular TA administration combined with ACR. The improvement in ROM abduction at an early stage (within three months of treatment) is considered a significant benefit of steroid use.
ACR is a widely performed surgical treatment for frozen shoulder with reported good clinical outcomes.
In this study, both groups demonstrated postoperative improvement; however, the improvement in abduction ROM was significantly greater in the ACR+TA group than in the ACR group. A previous study suggests that frozen shoulder occurs as a consequence of chronic inflammation and capsular fibrosis.
Therefore, we hypothesized that administration of TA would suppress surgery-induced inflammation, which in turn would inhibit fibrosis and improve ROM soon after surgery. On the other hand, no significant changes were observed between 3 and 6 months, which may be a ceiling effect due to this short observation period.
In previous studies, the incidence of osteonecrosis in rabbits injected intramuscularly with mPSL was significantly higher than in those injected with TA or prednisolone.
In our study, factors that may have influenced results are the administration of steroids while performing confirmatory arthroscopy and the use of another type of steroid (TA). It remains to be seen whether the results would differ depending on the steroid used.
In our study, the improvement in night pain was significantly greater in the ACR group than that in the ACR+TA group three months after surgery. Preoperative night pain score was 5.1±0.8 in the ACR group and 4.1±0.8 in the TA group, which was not significantly different, but may be related to the higher night pain in the TA group. The NRS pain scores are interpreted as follows: 0 as no pain, 1–3 as mild pain, 4–6 as moderate pain, and 7–10 as severe pain.
The night pain in the TA group at 3 months postoperatively was mild pain, which can be treated with analgesics. Although only a prediction, it is also common for pain to occur after a day of heavy shoulder movement, and it is possible that the pain was caused by the large amount of shoulder movement. At 6 months, there was no significant difference in night pain between the groups. There was no significant difference in clinical scores, and we do not consider this to be a major clinical problem. There are large individual differences in pain perception, and we would like to consider further detailed pain assessment.
This study has some limitations. First, this was a retrospective study, and the surgeon and evaluator were not unified or blinded, which may have affected the results. Therefore, regarding postoperative evaluation, a prospective, randomized controlled trial in which the surgeon and postoperative evaluator are different may be necessary in the future. Second, pain was evaluated using only the NRS, and it may be important to evaluate pain from multiple perspectives. We did not check the amount of analgesics used and did not use a uniform protocol. However, because of the ethical viewpoints of patients, it may be difficult to establish a protocol.
We achieved early recovery of shoulder abduction in patients with frozen shoulder with the administration of TA with ACR. Although there was a significant difference in pain, it was within a manageable range, and we believe this protocol can be a treatment option for frozen shoulder if early recovery is desired.
We thank the personnel of the Gunma University Graduate School of Medicine for their assistance and cooperation in this study. Finally, we would like to thank Editage (www.editage.com) for English language editing.
Short-term outcomes after arthroscopic capsular release for adhesive capsulitis.
The authors, their immediate families, and any research foundation with which they are affiliated have not received any financial payments or other benefits from any commercial entity related to the subject of this article.
The Gunma University Ethical Review Board for Medical Research Involving Human Subjects (HS2021-168) approved this study. Informed consent for participation and publication was obtained from the participants.
Level of evidence: Level III; Retrospective Cohort Comparison; Treatment Study;