Therapeutic effects of mobilization in alleviating pain and improving shoulder mobility in adhesive capsulitis – A systematic review

INTRODUCTION

Frozen shoulder (FS), also known as adhesive capsulitis, presents as persistent pain and stiffness lasting over three months.^[1] The term “frozen shoulder” was first used in 1934, later it was labeled as “Periarthritic scapulohumeral’ in 1945.^[2] This condition affects 3–5% of the general population, with a heightened prevalence of 20% in diabetics^[3] and is most commonly seen in manual workers aged 40–60.^[4]

While all movement ranges are restricted in FSs, external rotation, abduction, and flexion are notably compromised. These symptoms often do not manifest radiologically. Although its exact cause is unknown, risk factors include diabetes, shoulder injuries, Parkinson’s disease, thyroid issues, stroke, and complex regional pain syndrome.^[5,6]

Mobilization of the shoulder offers physiological benefits, including enhancing synovial fluid circulation, which nourishes the cartilage. This boost in circulation, derived from physical activities at the joint, is further amplified by mobilization, enriching the avascular cartilage. Moreover, mobilization expands joint space and mitigates nociceptive pathways in the brainstem, offering pain relief.^[7] P. Nakandala et al. underlined the efficacy of manual therapy and physical therapy techniques, such as mobilization, in managing FSs.^[8] Maitland mobilization is particularly beneficial in improving the range of motion (ROM) and alleviating pain in FS patients. Meanwhile, the Kaltenborn technique, a specialized mobilization stretch, has shown promise in enhancing joint flexibility, with both Kaltenborn and Maitland approaches demonstrating pain reduction and improved ROM in patients with FSs.^[9,10]

Mobilization with movement (MWM), a manual therapy method pioneered by Mulligan, has been recognized for its prompt effects on musculoskeletal pain alleviation and enhancement in joint ROM.^[11] On the other hand, the Cyriax approach is grounded in treating soft-tissue lesions, proving advantageous for conditions involving tears in tendons, muscles, bursae, and ligaments surrounding the joint. One of its renowned techniques is friction massage, which has been proposed as a remedial method for the musculoskeletal system.^[12] A study by Guler-Uysal and Kozanoglu comparing the effects of the Cyriax approach with MWM, in conjunction with conventional therapies such as hot packs and short-wave diathermy, found that the Cyriax method exhibited promising outcomes in pain mitigation and ROM enhancement.^[13]

While existing research acknowledges the potential benefits of mobilization, there remains a gap. A systematic review could offer a more profound insight into the impact of mobilization on FSs, thereby enriching the field and guiding future interventions where clear benefits have yet to be established.

This review’s research question was: what is the effect of mobilization on pain and ROM capacity in patients with FSs? The study’s primary goal was to assess the effectiveness of mobilization in alleviating pain and increasing ROM in patients with FSs. The study also aimed to determine the particular efficacy of mobilization strategies in relieving pain and enhancing ROM in these individuals. Finally, the researchers wanted to compare the outcomes of mobilization techniques to those of other physical therapy procedures used to treat FSs.

MATERIALS AND METHODS

This study used the positivist method, a quantitative approach that depends on empirical data and statistical analysis to set research objectives.

The researchers followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses standards in their work.

RESULTS

Study selection

The process of identifying and selecting articles for the review is illustrated in Figure 1. Initially, 37 records were identified through database searches, with 26 coming from CINAHL, 4 from Medline, 1 from AMED, and 6 from PubMed, after removing duplicate entries. During the screening phase, 22 articles were excluded, with 13 of them having interventions that were unrelated to the study’s focus. This left 15 articles that met the eligibility criteria. After further evaluation, six non-RCTs were excluded, and three full-text articles were also removed because they did not fulfill the inclusion criteria. Those studies were focused on different outcome measures compared to the predefined criteria. Ultimately, six studies were included in the quantitative synthesis and consequently were incorporated into this systematic review.

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Figure 1:

PRISMA flow diagram. PRISMA: Preferred Reporting Items for Systematic Reviews and Meta-Analyses. RCTs: Randomized controlled trials.

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DISCUSSION

The impact of mobilization as a therapy for FS was investigated in all of the studies included in this review. Three of the six trials found that mobilization had a favorable effect on pain levels in individuals with FSs. However, two trials revealed that mobilization did not affect pain. Based on these findings, we can consider mobilization as a treatment option for FS. Nonetheless, it is crucial to carefully consider the methods and limitations of the studies included in the review when interpreting these results. The variability in study outcomes may be influenced by factors such as the specific mobilization techniques used, the duration of treatment, and the patient populations studied.

Doner et al.^[29] found that Mulligan mobilization (n = 20) reduced pain more than conventional treatment (n = 20) in a short-term RCT, but the study quality was moderate, with a PEDro score of 6/10, Razzaq et al.^[28] demonstrated that combining conventional treatment with mobilization (n = 32) was more effective in reducing pain than muscle energy techniques (n = 32) alone (P < 0.001). However, the study quality was moderate with a PEDro score of 7/10 and lacked concealed allocation.^[29]

Noureen et al.^[30] found that angular mobilization (n = 25) was significantly effective in reducing pain compared to stretching (n = 25), as per NPRS (P < 0.001). However, like Doner et al.^[29] and Razzaq et al.,^[28] the study had quality limitations due to missing concealed allocation and blinding, scoring only 5/10 on the PEDro scale. The absence of adequate follow-up further compromises the reliability of its outcomes.

Mobilization techniques, including scapular and glenohumeral interventions, appear promising in alleviating FS pain.^[31,33] However, study quality and design inconsistencies, such as blinding and concealed allocation, influence interpretations.^[28-30] The underlying mechanism might be attributed to the neurophysiological effects where mobilization activates mechanoreceptors and inhibits nociceptors, providing pain relief.^[34] A thorough systematic review on this subject is notably missing, emphasizing a research opportunity.

Most reviewed studies indicate that mobilization techniques, especially Mulligan mobilizations, effectively improve the flexion ROM in patients with FSs. Out of the six studies assessing flexion ROM, five noted improvements. Mulligan mobilizations consistently demonstrated efficacy in both studies where they were implemented.^[29,28] While one study evidenced a positive outcome with scapular mobilizations,^[33] another indicated neutral effects.^[32] Furthermore, Duzgun et al.^[33] showed an 8-degree improvement in flexion after scapular mobilization, a finding mirrored by Surenkok et al.^[35] Meanwhile, studies utilizing passive mobilizations and glenohumeral joint mobilizations showed mixed results: one presented positive results,^[30] and the other depicted neutral outcomes.^[31] These findings, even with some methods limitations in certain studies, accentuate the potential therapeutic significance of mobilization methods for FS treatment.

Most studies reviewed have indicated that different mobilization techniques can improve abduction ROM in FS patients. Specifically, Mulligan mobilizations effectively improved abduction ROM.^[28] Angular joint mobilizations also showed positive results for abduction ROM despite the study’s lower quality.^[30] Scapular mobilizations yielded mixed outcomes: one study found a 6-degree improvement in abduction,^[33] echoing findings from Surenkok et al.^[35] Conversely, Yang et al.^[32] did not observe a significant increase in abduction ROM. Notably, Yiasemides et al.^[31] (n = 98) showed neutral effects for glenohumeral joint mobilizations. Overall, while various mobilizations positively impacted abduction ROM, results were not uniformly consistent across all studies.

The limited research available indicates that specific mobilization techniques, such as Mulligan mobilization, are effective in improving the extension ROM in patients with frozen shoulders. Razzaq et al.^[28] and Noureen et al.^[30] both found significant improvements in extension ROM following their respective interventions, with P < 0.05. It is noteworthy that the quality of Noureen et al.^[30] was lower and that blinding was not consistently followed in studies employing Mulligan mobilizations. Overall, the evidence suggests a positive effect of mobilization techniques on extension ROM in FSs, but more comprehensive research is required to solidify these findings.

The limited research available underscores Mulligan mobilization’s effectiveness in improving adduction ROM in FSs. Both Doner et al.^[29] and Razzaq et al.^[28] studies demonstrated significant improvements in adduction ROM after employing this technique, with P < 0.05. Both studies endorse the positive impact of Mulligan mobilization, and it emerges as a promising intervention for enhancing adduction ROM in FSs, even though further expansive research is warranted to solidify these outcomes.

When evaluating the external rotation ROM in patients with FSs, there is a consistent indication of improvement across the reviewed studies. Specifically, Mulligan mobilization, employed in the studies by Doner et al.^[29] and Noureen et al.^[30] demonstrated positive results, although with some method concerns, such as the absence of blinding. Similarly, Yang et al.^[32] and Duzgun et al.^[33] found improvements in external rotation, with their findings reinforced by respective PEDro scores of 7/10. The effectiveness of both scapular and passive mobilizations in enhancing external rotation was also consistent across studies. These findings collectively highlight the efficacy of various mobilization techniques in ameliorating external rotation in a FS. However, further research with rigorous methods is essential for a more comprehensive understanding.

Mixed results have been noted when reviewing the effectiveness of various mobilization techniques on the internal rotation ROM in patients with FSs. Doner et al.^[29] presented a significant improvement in internal rotation when Mulligan mobilization was employed, as evidenced by P = 0.001. Conversely, in the latter study, Yang et al.^[32] and Dugzun et al.^[33] reported no significant improvements in internal rotation despite slight increases in degrees of rotation.

Although Mulligan mobilization showed a positive outcome in one study, scapular mobilizations and other techniques did not yield universally consistent results. Thus, it appears that while some mobilization techniques can enhance internal rotation in FS cases, further rigorous and extensive research is required to establish a consistent and effective therapeutic approach.

This systematic review emphasizes the critical role of clinical research in transforming knowledge into practical applications for clinical practitioners, which is consistent with the ideas outlined in recent literature.^[36] Practically, therapists can incorporate mobilization techniques to alleviate pain and enhance shoulder mobility in patients with FSs. Personalized application of these evidence-based interventions ensures a tailored and effective physiotherapeutic approach in clinical practice.

CONCLUSION

It is evident that mobilization techniques, including Mulligan, scapular, and angular joint mobilizations, yield promising results for FS patients. Notably, these treatments have demonstrated a marked reduction in pain spanning from six weeks to six months, alongside notable enhancements in the ROM across various axes: flexion, extension, abduction, adduction, external rotation, and internal rotation. In essence, mobilization stands out as a beneficial and effective approach to addressing both pain and mobility challenges associated with a FS.

It is reassuring to note the absence of reported adverse effects, underscoring the safety of the treatment. However, while these findings are promising, there is still room for exploration, especially regarding the potential impacts of other mobilization techniques, such as Cyriax, Maitland, and Kaltenborn, on FS management.