Abstract
Purpose
To analyze the recovery duration of pain and functional activity after conservative treatment, including oral medication, injections, and rehabilitation, for frozen shoulder among patients based on the severity of their symptoms.
Methods
The study involved patients with new reports of shoulder night pain considered more severe than daytime pain and limited range of motion between January 2021 and December 2021 at the Tokyo Sports and Orthopaedic Clinic. Patients with recent shoulder treatment, a history of shoulder injury, rotator cuff tears, arthritic changes, or shoulder trauma were excluded. After dividing patients into 3 groups by severity of stiffness (group 1, severe; group 2, moderate; and group 3, mild), we recorded retrospective data on range of motion and details of conservative treatment, such as oral medication, injection frequency, and physical therapy, each time the patient visited.
Results
The study included 113 shoulders from 106 patients (39 men and 67 women), with a mean age of 54 years (range, 43-75 years). For night pain treatment, median recovery time was 1, 1, and 0.5 months for groups 1, 2, and 3, respectively, with no significant difference. Group 1 used oral medication and injections significantly more than groups 2 and 3 (P < .004). No significant differences were found in the number of rehabilitation sessions among the 3 groups, which had averages of 17.5, 12, and 16 sessions in groups 1, 2, and 3, respectively. Median recovery times for range of motion were 10, 9, and 12 months in groups 1, 2, and 3, with no significant differences. Similar results were observed for oral medication duration, injection frequency, and rehabilitation sessions. Group 1 had median durations of 1 month for oral medication, 3 injections, and 17.5 rehabilitation sessions; group 2 had durations of 1 month, 2 injections, and 12 sessions; group 3 had durations of 1, 1.5, and 16 months for oral medication, injections, and rehabilitation sessions, respectively.
Conclusions
Conservative treatment is effective for the treatment of frozen shoulder. In this study, it improved night pain within a month and enhanced range of motion significantly within a year.
Level of Evidence
Level III, retrospective cohort study.
Frozen shoulder stands out as one of the most frequently encountered conditions in orthopaedics, impacting around 2% to 5% of the population1 and accounting for 15% of all shoulder-related pathological issues, with pain and range of motion (ROM) being the predominant concerns2 and also affecting the daily activities of individuals, particularly in the middle to older age groups.3 It is more commonly observed in women than men and can be categorized into primary and secondary frozen shoulder.4 Codman5 coined the term frozen shoulder to describe various conditions leading to spasms of the short rotators or adhesions around the joint or bursae. While shoulder stiffness can result from factors like trauma or systemic diseases, the origin of frozen shoulder remains unclear. Frozen shoulder with an unknown cause is also termed idiopathic adhesive capsulitis.
The diagnosis of frozen shoulder relies on the patient’s history, particularly the presence of pain, especially during the night, and limitations in both active and passive movements.6 Additionally, there are no evident anatomic or systemic abnormalities or diseases that directly account for these characteristic signs and symptoms.7 Some associated imaging signs are present, but they are not major.
Given that this is often a self-limiting condition, particularly in instances of primary shoulder stiffness, the initial recommendation is conservative therapy.8 Currently, there is no consensus regarding the preferred treatment approach. Initial treatment strategies center on conservative measures and intensive physical therapy.9 Numerous nonsurgical treatments exist for idiopathic adhesive capsulitis, such as oral medication, steroid injections, and physical therapy. Challoumas et al.10 found that the early use of intra articular corticosteroid in patients with frozen shoulder of less than a 1-year duration is associated with better outcomes. Aside from steroid injections, some studies have highlighted hydrodilatation as a method to enhance the ROM. However, hydrodilatation may not provide any significant benefits over intra-articular steroid injections.11 Lin et al.12 used the proprioceptive neuromuscular facilitation technique to improve the shoulder joint structure in patients with frozen shoulder. Acupuncture has been utilized in some centers for the treatment of primary frozen shoulder, showing effective pain relief and improved forward flexion.13,14 Extracorporeal shockwave therapy appears to benefit patients with frozen shoulder by reducing pain and enhancing functionality.15 Yu et al.16 found that local platelet-rich plasma injections are among the effective options for reducing pain and improving shoulder mobility in patients with frozen shoulder. As mentioned earlier, various conservative treatment methods are available, with success rates reaching up to 90%.17, 18, 19 Most patients respond very well to a combination of conservative treatments, resulting in gradual resolution of symptoms in 12 to 18 months.20 However, the optimal timing for treatment remains variable and uncertain.
The objective of this research was to analyze the recovery duration of pain and functional activity after conservative treatment, including oral medication, injections, and rehabilitation, for frozen shoulder among patients based on the severity of their symptoms.
We hypothesize that recovery time for night pain and ROM would be shorter in patients with mild cases compared to those with severe cases and that conservative treatments such as medication, injections, and rehabilitation would be significantly effective in treating frozen shoulder.
Methods
Selection Criteria
This research has been approved by the authors’ affiliated institutions, and informed consent was obtained from all patients and relevant persons.
Between January 2021 and December 2021, a total of consecutive stiff shoulders treated at our institute were retrospectively evaluated in this study. The exclusion criteria were as follows: patients with a history of shoulder surgery, patients who had received treatment from another clinic within the past 3 months, patients with radiographic evidence of osteoarthritic changes, patients with a rotator cuff tear, patients who had experienced a traumatic event, patients who were lost to follow-up, and patients who underwent surgery.
Data Collection
This study was a retrospective cohort study. We reviewed and collected data from medical records that had been recorded by the same physician (H.S.). We measured shoulder ROM in 3 directions: passive forward flexion, external rotation with the arm at the side, and internal rotation. If the patient is in pain, assessing the ROM in the shoulder becomes challenging. Consequently, we will conduct the examination with the patient in a supine position. Also, we consider a patient to have achieved recovery if they gain forward flexion exceeding 80% of the range of motion based on their first visit. Night pain was recorded through patient interviews, also conducted by the same physician. We consider nighttime pain, which causes a patient to wake up, to be more severe than pain experienced when the patient is awake. Finally, we documented data on conservative treatment, including medication, injections, and physiotherapy.
Outcome Assessment
The baseline parameters for patient assessment included sex, age, affected side, and ROM during the initial and final visits. The recovery period’s duration was documented with a focus on 2 symptoms: night pain and limited ROM, which served as the primary outcome. Additionally, the analysis involved examining the number of injections, physiotherapy sessions, and the duration of oral medication use as secondary outcomes.
Patterns and Severity of ROM Limitation
In accordance with the investigation conducted by Ueda et al.,21 we systematically classified patients into 3 distinct groups based on the extent of shoulder stiffness. Group 1 had severe and global loss, showing marked constraints in passive ROM across all 3 measured directions indicative of adhesive capsulitis: forward flexion restricted to ≤100°, external rotation limited to ≤10°, and internal rotation confined to a level not surpassing the L5 vertebra. Group 2 exhibited severe limitations in at least 1 direction, albeit without a global loss of motion. Group 3 encompassed the remaining shoulders and was characterized as those manifesting mild to moderate limitation.
Statistical Analysis
The Kruskal-Wallis test was utilized to assess differences in recovery time and treatment frequency across the groups. Additionally, a 1-way analysis of variance was employed to compare demographic factors (age, sex, and side) and ROM between the groups. The level of significance was set at P < .05.
Results
This study retrospectively evaluated 113 consecutive stiff shoulders in 106 patients (39 men and 67 women), with a mean age of 54 years (range, 43-75 years) (Table 1).
Table 1.
Demographic Data
| Characteristic | Group 1 (G1): Severe Global Loss (n = 58) | Group 2 (G2): Moderate Stiffness (n = 36) | Group 3 (G3): Mild Stiffness (n = 12) |
P Value |
|||
|---|---|---|---|---|---|---|---|
| Among Groups | G1 vs G2 | G1 vs G3 | G2 vs G3 | ||||
| Age, y | 55.84 ± 8.11 | 51.53 ± 7.01 | 53.25 ± 6.72 | .029∗ | .026∗ | .855 | ≥.999 |
| Sex | .276 | .115 | .876 | .401 | |||
| Female | 40 (69) | 19 (52.8) | 8 (66.7) | ||||
| Male | 18 (31) | 17 (47.2) | 4 (33.3) | ||||
| Side | (n = 62) | (n = 39) | (n = 12) | .478 | .271 | .824 | .371 |
| Left | 34 (54.8) | 17 (43.6) | 7 (58.3) | ||||
| Right | 28 (45.2) | 22 (56.4) | 5 (41.7) | ||||
NOTE. Values are presented as mean ± standard deviation for continuous variables and as n (%) for categorical variables. P values were calculated using the analysis of variance test for group comparisons, with post hoc Bonferroni correction for continuous variables and the χ2 test for categorical variables.
Statistical significance was defined as P < .05.
Group 1 consisted of 62 shoulders (34 left and 28 right) in 58 patients (40 women and 18 men). The mean age was 55 years. Group 2 consisted of 39 shoulders (17 left and 22 right) in 36 patients (19 women and 17 men). The mean age was 51 years. Group 3 consisted of 12 shoulders (7 left and 5 right) in 12 patients (8 women and 4 men). The mean age was 53 years. Analysis of variance and χ2 tests found that group 1 was significantly older than group 2 (P < .029).
Night Pain Subsidence
The median recovery times were 1, 1, and 0.5 months in groups 1, 2, and 3, respectively (Table 2). The Kruskal-Wallis test indicated that the recovery period was not significantly different among the 3 groups. Group 1 significantly utilized oral medication and number of injections more than group 2 and group 3 (P < .004). Additionally, there were no significant differences in the number of rehabilitation sessions among the 3 groups.
Table 2.
Night Pain’s Subsidence and Range of Motion Improvement
| Characteristic | Group 1 (G1): Severe Global Loss (n = 62) | Group 2 (G2): Moderate Stiffness (n = 39) | Group 3 (G3): Mild Stiffness (n = 12) |
P Value |
|||
|---|---|---|---|---|---|---|---|
| Among Groups | G1 vs G2 | G1 vs G3 | G2 vs G3 | ||||
| Night pain subsidence | |||||||
| Duration, mo | 1 (1, 1) | 1 (0, 1) | 0.5 (0, 1.5) | .060 | .025∗ | .155 | .915 |
| Medication, mo | 1 (0, 1) | 0 (0, 1) | 0 (0, 1) | .004∗ | .002∗ | .059 | .878 |
| Injection, times | 2 (1, 3) | 1 (0, 2) | 0 (0, 2.5) | .004∗ | .002∗ | .071 | .636 |
| Rehabilitation, times | 0 (0, 2) | 0 (0, 1) | 0 (0, 2.5) | .900 | .753 | .819 | .659 |
| ROM improvement | |||||||
| Duration, mo | 10 (6, 14) | 9 (6, 11) | 12.5 (8.5, 18.5)† | .108 | .437 | .121 | .023∗ |
| Medication, mo | 1 (1, 2) | 1 (0, 1) | 1 (0, 2.5) | .077 | .020∗ | .747 | .422 |
| Injection, times | 3 (2, 4) | 2 (1, 4) | 1.5 (0, 4) | .066 | .041∗ | .119 | .620 |
| Rehabilitation, times | 17.5 (10, 27) | 12 (8, 21) | 16 (11.5, 18.5) | .123 | .050 | .654 | .229 |
NOTE. Values are presented as median (interquartile range) for nonnormally distributed data. P values were calculated using the Kruskal-Wallis test for group comparisons, with post hoc Mann-Whitney U tests performed when applicable.
ROM, range of motion.
Statistical significance was defined as P < .05.
Significant difference observed between Group 2 (moderate stiffness) and Group 3 (mild stiffness) in the duration of ROM improvement.
ROM Improvement
The median recovery times were 10, 9, and 12 months in groups 1, 2, and 3, respectively (Table 2). The Kruskal-Wallis test found no significant differences in recovery time between the 3 groups. The same held true for oral medication period, times of injection, and rehabilitation sessions. Group 1 exhibited median durations of 1 month for the oral medication period, 3 injections, and 17.5 rehabilitation sessions. Group 2 showed median durations of 1 month for oral medication, 2 injections, and 12 rehabilitation sessions. In group 3, the median durations for oral medication, number of injections, and number of rehabilitation sessions were 1 month, 1.5 injections, and 16 sessions, respectively.
Range of Motion
The average forward flexion in group 1 during the initial visit was 89.68, which improved to 166.45 by the final visit (Table 3). In group 2, the mean forward flexion started at 112.05 for the first visit and progressed to 170.64 by the final visit. Group 3 exhibited an initial mean forward flexion of 130.42, which increased to 173.33 during the final visit. As for external rotation, group 1 had a mean of 1.37 during the first visit and 51.69 during the final visit. In group 2, the mean external rotation began at 16.79 for the first visit and advanced to 56.79 by the final visit. Group 3 started with a mean external rotation of 27.5 during the first visit and reached 58.33 by the final visit. Table 4 displays the changes in internal rotation between the initial and final visits. Grouping criteria are based on Ueda et al.21
Table 3.
Final Range of Motion of Forward Flexion and External Rotation
| Characteristic | Group 1 (G1): Severe Global Loss (n = 62) | Group 2 (G2): Moderate Stiffness (n = 39) | Group 3 (G3): Mild Stiffness (n = 12) |
P Value |
|||
|---|---|---|---|---|---|---|---|
| Among Groups | G1 vs G2 | G1 vs G3 | G2 vs G3 | ||||
| Forward flexion | |||||||
| First ROM | 89.68 ± 10.28 | 112.05 ± 12.39 | 130.42 ± 15.14 | <.001∗ | <.001∗ | <.001∗ | <.001∗ |
| Final ROM | 166.45 ± 8.17 | 170.64 ± 3.66 | 173.33 ± 3.26 | <.001∗ | <.001∗ | <.001∗ | .009∗ |
| External rotation | |||||||
| First ROM | 1.37 ± 6.02 | 16.79 ± 15.37 | 27.5 ± 11.38 | <.001∗ | .007∗ | .003∗ | .644 |
| Final ROM | 51.69 ± 12.58 | 56.79 ± 11.15 | 58.33 ± 8.35 | .048∗ | .107 | .226 | ≥.999 |
NOTE. Values are presented as mean ± standard deviation. P values were calculated using the analysis of variance test for group comparisons, with post hoc Bonferroni correction for continuous variables.
ROM, range of motion.
Statistical significance was defined as P < .05.
Table 4.
Final Range of Motion of Internal Rotation
| Final ROM of Internal Rotation |
Total | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| B | L | L1 | L2 | L3 | L4 | L5 | S | T7 | T8 | T9 | T10 | T11 | T12 | |||
| Internal rotation | B | 4 | 1 | 2 | 1 | 2 | 0 | 1 | 2 | 3 | 15 | 21 | 12 | 7 | 3 | 74 |
| L1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 1 | |
| L3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 5 | 0 | 1 | 0 | 0 | 6 | |
| L4 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 1 | 4 | 0 | 1 | 0 | 8 | |
| L5 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 2 | 1 | 0 | 1 | 0 | 7 | |
| S | 0 | 0 | 0 | 0 | 2 | 1 | 0 | 0 | 0 | 2 | 1 | 3 | 3 | 0 | 12 | |
| T7 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 1 | |
| T9 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 2 | 0 | 0 | 3 | |
| T11 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 1 | |
| Total | 4 | 1 | 2 | 1 | 6 | 3 | 2 | 2 | 3 | 29 | 27 | 18 | 12 | 3 | 113 | |
NOTE. B refers to the buttock, L refers to the lumbar region, T refers to the thoracic region, and the numbers represent the range of motion in degrees.
ROM, range of motion.
Oral Medication
Oral medications designed to alleviate night pain were categorized into 3 groups: opioids, steroids, and a combination of both. The median durations for using opioids, steroids, and mixed medication in group 1 were 1 month, 2 months, and 1 month, respectively. In group 2, the respective median durations for using opioids, steroids, and mixed medication were 1 month, 1 month, and 1 month. As for group 3, the median durations for using opioids, steroids, and mixed medication were 2 months, 2 months, and 1 month. There was no significant difference in the duration of using each medication except for duration of using steroid and opioid in group 1.
Discussion
The most important finding is that conservative treatment is effective for frozen shoulder patients across all severity groups.
Several studies support the concept of conservative treatment for frozen shoulder. Russo et al.22 discovered that a combined pharmacological and rehabilitation approach in the conservative treatment of adhesive capsulitis effectively resolved pain and stiffness in 96% of the patients. Stinton et al.23 indicated that high-intensity stretching therapy proved effective for patients experiencing shoulder motion loss, as evidenced by notable improvements in ROM across all planes. Russell et al.24 found that a hospital-based exercise class can lead to a speedy recovery from frozen shoulder with fewer hospital visits, surpassing the effectiveness of individual physiotherapy or home exercise programs. The study by Brealey et al.25 shows that early, organized physiotherapy combined with a steroid injection presents an accessible and cost-effective approach for addressing frozen shoulder. Another study on steroid injection, conducted by Pushpasekaran et al.,26 concludes that the 3-site approach to steroid instillation in frozen shoulder is a safe method. It also yields early recovery, improves shoulder function, and reduces the likelihood of relapses. A study on the effectiveness of movement combined with mobilization for adhesive capsulitis of the shoulder found that mobilization plays a crucial role in improving ROM and alleviating pain. Its impact is particularly significant when incorporated into a supervised exercise program.27 However, few studies investigate the recovery time in conservative treatment for frozen shoulder.
Predicting the time frame for conservative treatment of shoulder stiffness remains challenging due to the diverse treatment approaches,28 such as oral medication, injections, and physical therapy. The varying degrees of stiffness severity further contribute to the uncertainty in outcomes. To address these confounding factors, the study categorized shoulder stiffness severity based on criteria from Ueda et al.21 Additionally, we differentiated symptoms into night pain and limited ROM. The most prominent finding of this study was that the mean periods to treat night pain and ROM were 1.2 and 10.5 months, respectively.
The inclusion of a substantial number of patients allows for a thorough statistical analysis, enhancing our understanding of the correlation between conservative treatments and the recovery time for shoulder stiffness. Another key strength is the consistent and standardized physical examinations conducted by the same orthopaedic doctor, minimizing variability and ensuring reliability in assessing participants’ physical conditions. In essence, the combination of a large subject pool and consistent examination procedures strengthens the study’s reliability as a foundation for exploring the relationship between conservative treatments and shoulder stiffness recovery.
Limitations
Several limitations are inherent in this study. First, a notable limitation is the lack of specificity in detailing the various components of the treatments administered. For instance, the study lacks documentation regarding the sessions of physical therapy, an aspect pivotal to conservative treatment outcomes. Without a detailed account of the procedure of these sessions, the study misses an opportunity to correlate the intensity and duration of physical therapy with the observed outcomes, potentially limiting the depth of the analysis. Second, the absence of information on the dosage and specific medications used in injection therapies adds another layer of limitation to the study. Variations in the types and amounts of injected substances, critical elements in the treatment protocol, remain unaccounted for, potentially confounding the overall interpretation of the efficacy of injection-based interventions. The final limitation is that we rely solely on one direction, forward flexion, to determine the recovery of ROM. This is due to the narrow scale and difficulty in calculating the other 2 directions (internal and external rotation).
Conclusions
Conservative treatment is effective for the treatment of frozen shoulder. In this study, it improved night pain within a month and enhanced ROM significantly within a year.
Disclosures
All authors (C.K., T.I., M.T., H.S.) declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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