Definition, Diagnosis, Treatment, and Prognosis of Frozen Shoulder: A Consensus Survey of Shoulder Specialists

This study was approved by Institutional Review Board of Keimyung University Dongsan Hospital (IRB No. 2018 06046).

Of the 95 shoulder specialists, 71 (74.7%) completed the survey by answering all questions; 24 shoulder specialists did not reply within the specified deadline. All the questions and answers of this survey are presented in Table 1.

Table 1
Questions and Answers about Frozen Shoulder

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Treatment of FS

On question 10, 47.9% either agreed or strongly agreed that factors such as the type or dose of local anesthesia or the volume of normal saline, not the dose of corticosteroid, affect the outcome; 33.8% either disagreed or strongly disagreed. On question 11, 70.5% either agreed or strongly agreed that an image-guided technique is necessary for intra-articular corticosteroid injection. On question 12 about the frequency of intra-articular corticosteroid injections in a single patient, 9.9% responded not necessary; 62.0%, once; 19.7%, twice; 7.0%, three times; and one respondent (1.4%), four times or more.

Questions 16 through 18 were about the propriety of 12 specific treatments including nonoperative and operative strategies in each stage of FS (stage I, freezing; stage II, frozen; stage III, thawing). The responses are summarized in Table 2. In treatment of FS stage I, II, and III, the need for education was identified by 98.6%, 97.2%, and 98.6% of the respondents, respectively; 97.2%, 94.4%, and 85.9% agreed with using NSAIDs; 71.8%, 76.1%, and 52.1% agreed with using intra-articular corticosteroid injection; and 88.7%, 97.2%, and 95.8% agreed with using stretching exercise.

Table 2
Agreement on the Proper Treatment at Each Stage of Frozen Shoulder (Q16–Q18)

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Prognosis of FS

On question 13, 63.4% of the respondents either agreed or strongly agreed that intra-articular corticosteroid injection can reduce duration of FS. Question 14 asked whether patients with diabetes are predicted to have poor prognosis after conservative treatment: 62.0% either agreed or strongly agreed, whereas 29.6% either disagreed or strongly disagreed with this statement. Question 15 was about the percentage of patients who did not respond well to conservative treatment in clinical practice: 45.1% responded < 5%; 32.4%, 5%–10%; 9.9%, 11%–20%; 8.4%, 21%–30%; and 4.2%, > 30% (Fig. 1).

Fig. 1
Proportion of the patients who did not respond to conservative treatment.

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Our study revealed that there is a general consensus among Korean shoulder specialists on the definition and treatment of FS, but not on the classification of FS. Most respondents agreed with the propriety of education, supervised neglect, NSAIDs, intra-articular corticosteroid injection, and stretching exercise in treatment at each stage of FS. Among the respondents, 22.5% answered that more than 10% of their patients with FS did not respond to conservative treatment.

Recent reports have shown a general consensus on the definition of FS.6, 12, 13, 17) In a consensus study by Zuckerman and Rokito,6) 82% of the respondents either agreed or strongly agreed with the proposed definition of FS, and 85% either agreed or strongly agreed with the categorization of FS into the primary and secondary types. The results of our survey study are consistent with those of Zuckerman and Rokito. In our study, 84.5% either agreed or strongly agreed with the suggested definition of FS (question 1), and 88.8% either agreed or strongly agreed that FS should be categorized into the primary and secondary types (question 2). Several studies suggested that FS diagnosed after trauma should be classified as secondary and can be attributed to the result of synovitis with fibrotic cascades.8, 14, 21) However, in our study, 67.6% of respondents agreed with regarding FS after minor trauma or overuse as primary FS, possibly because of confusion in the definitions of trauma, minor trauma, and overuse, which may affect the assignment of disease category.

Unlike the definition of FS, the classification of FS appears to be controversial. Zuckerman and Rokito6) asked ASES members, “Is the division of secondary types of FS into intrinsic, extrinsic, and systemic appropriate?” and 66% either agreed or strongly agreed. Our study revealed the lack of consensus about questions 4 (“Do you think that FS diagnosed in patients with systemic disease such as thyroid disease or hyperlipidemia should be considered secondary FS?”) and 5 (“Do you think that FS diagnosed in patients with diabetes should be considered secondary?”). On question 4, 43.7% either agreed or strongly agreed and 36.6% either disagreed or strongly disagreed. This question had the highest no opinion responses (19.7% of the respondents). On question 5, 45.0% either agreed or strongly agreed and 40.9% either disagreed or strongly disagreed. Griesser et al.12) systematically reviewed studies on primary FS in patients with diabetes and concluded that diabetes is a poor prognostic factor for FS. However, Zuckerman and Rokito6) suggested that FS in patients with systemic diseases such as diabetes or thyroid disease is secondary. Furthermore, there is a point of view that FS in patients with diabetes should be classified separately from primary or secondary FS.16) Whether FS in patients with systemic disease should be considered as a subclass of secondary FS appears to be controversial. A new or modified classification of FS seems to be needed to achieve a consensus.

In patients with FS, radiographic studies including plain radiography, arthrography, ultrasonography, or MRI are used to exclude other causes of shoulder pain and can be complementary in the diagnosis.13) In our study, most shoulder specialists agreed with using plain radiography (71.9%) and ultrasonography (64.8%) but fewer respondents agreed with using MRI (36.5%) in the diagnosis of FS. These results demonstrate that shoulder specialists can diagnose FS through clinical presentation and minimum radiologic examination.

The treatment of FS remains controversial because the level of evidence for various treatments is limited.13) Controlled prospective studies are difficult to design and perform because of controversies in the definition, classification, diagnosis, and stages of FS. Kwaees and Charalambous20) reported a survey of FS treatment by 88 members of the British Elbow and Shoulder Society. The agreement was 67.8% for physiotherapy and 54% for corticosteroid injection used for treatment of stage II FS. The authors concluded that the management of FS varies substantially among physicians and is largely based on personal experience and training rather than strong evidence. Yet, we found a strong consensus on the proper treatment of FS: 97.2% agreed on education, 94.4% on NSAIDs, 76.1% on intra-articular steroid injection, and 97.2% on stretching exercise. Optimizing treatment depends on the recognition of the clinical stage at presentation because the condition progresses through predictable sequence.14) High-quality clinical trials should be performed to compare the treatment options available to the clinicians.

Since Codman7) stated in 1934 that “even the most severe cases recover with or without treatment in about 2 years” and “recovery is always sure and may be confidently expected,” the perception that the natural history of FS is benign and self-resolving within 2 years has been overwhelming.1, 11) However, clinicians often see patients complaining of residual pain and loss of motion even at 2 years after the onset of the disease.8, 9) Several studies suggested that diabetes is a poor prognostic factor for clinical outcome after treatment.12, 13, 17) In our study, 22.5% of the respondents answered that more than 10% of the patients with FS did not respond to conservative treatment. We asked whether patients with FS and diabetes are predicted to have poor prognosis after conservative treatment: 62.0% either agreed or strongly agreed. High-quality clinical trials would be necessary to evaluate the effectiveness of the treatment options and prognosis after treatment in patients with FS.

Our study has several limitations. First, the number of subjects is small. Nevertheless, the response rate was relatively high (74.7%) and all respondents were shoulder specialists working at residency or fellowship training hospitals. Second, our interpretation of the survey results might be ambiguous because of no gold-standard cutoff percentage for the agreement. In conclusion, this survey study revealed a general consensus among shoulder specialists in the definition and treatment of FS. However, classification of FS was found to be controversial.