Exercise therapy is effective for improvement in range of motion, function, and pain in patients with frozen shoulder: a systematic review and meta-analysis

Key Points

1. Research suggests that exercise is effective for improving range of motion, function, and pain in patients with frozen shoulder.
2. There is little evidence that adding interventions to exercise provides additional benefit.
3. Most of the evidence on these questions concerns the short-term, and few conclusions can be drawn about the most effective therapies in the long-term.

BACKGROUND & OBJECTIVE

Frozen shoulder is characterized by spontaneous, progressive inflammation and fibrosis of the shoulder joint, resulting in pain and loss of active and passive range of motion (1). It usually develops between the ages of 40-60 and is more common in women than men (2). The non-dominant shoulder is more likely to be affected (2). Frozen shoulder may be more common in people who perform sedentary jobs, and the risk is about 6 times higher in people with diabetes (3, 4).

This systematic review and meta-analysis collectively analyzed studies looking at the effect of exercise on frozen shoulder. There were two specific goals:

1. Compare the effect of exercise alone versus exercise with other interventions.
2. Compare the different methods of exercise to determine which were most effective.

The non-dominant shoulder is more likely to be affected by frozen shoulder.

The authors concluded that exercise for frozen shoulder is an effective treatment in the short-term, and that adding in passive modalities offers little or no additional benefit.

METHODS

• 33 studies were included in the systematic review, and 19 studies were included in the meta-analysis.
• The following outcomes were considered: range of motion (ROM), function/disability, pain, muscle strength, and patient satisfaction.
• Outcomes were analyzed for the short-term (less than 3 months), medium-term (3-9 months) and long-term (greater than 9 months).

RESULTS

Of the 33 studies, only 3 were considered high quality, and more than 20 were low quality.

The most common types of exercises were:

• Strengthening exercises
• PNF
• Muscle energy techniques
• Wand/wall exercises
• Pendulum exercises
• Various stretching or ROM exercises

Non-exercise-based therapies included:

• Thermotherapy
• Ultrasound
• Electrotherapy
• Manual therapy
• Oral medication
• Continuous passive motion
• Laser therapy
• Infrared therapy
• Spray and stretch technique
• Electromagnetic therapy

Analysis of the data was presented in terms of the following comparisons:

Multimodal versus exercise only

Analysis of 8 studies showed little or no evidence that multimodal programs were superior to exercise only programs in improving ROM, disability, and pain.

Programs with and without exercise

Analysis of 4 studies found little or no evidence that multimodal programs with exercise were better than multimodal programs without exercise. Although the programs involving exercise might have showed benefit for some measures of active ROM, there was no such evidence of benefit for passive ROM, and the evidence was uncertain for pain and disability.

Muscle energy techniques

Analysis of 7 studies found that programs using muscle energy techniques showed little to no difference in pain and ROM compared to programs with other exercises, although they may improve disability.

Stretching

Analysis of 2 studies found that adding stretches to a multimodal program with exercises may increase ROM, but the effects on function and pain are uncertain.

Supervised versus home exercise

1 study found that supervised exercises provided more benefit than home exercises for ROM and function.

LIMITATIONS

• Most of the studies included were low quality.
• The different studies were hard to compare because they used different types of exercise, different dosages of exercise, and combined different passive interventions with exercise.
• Most of the studies used a short time frame of less than 3 months, which is not that useful because frozen shoulder often lasts for more than a year.

CLINICAL IMPLICATIONS

Traditionally, physical therapy for frozen shoulder involves exercise, joint mobilization, education, and passive therapies like heating. Exercise is one of the most effective forms of physical therapy for musculoskeletal pain and has been shown to be effective in several forms of shoulder pain too.

In this paper, the authors concluded that exercise for frozen shoulder is an effective treatment in the short-term, and that adding in passive modalities offers little or no additional benefit. It should be noted however that the paper also provided evidence that conflicts with this, i.e. little to no evidence was found that multimodal programs with exercise were better than multimodal programs without exercise.

My conclusion from reading the study is that we currently don't know very much about the relative effectiveness of different treatments for frozen shoulder in the long-term. Further research is urgently needed to guide clinicians with their treatment selection for this challenging condition.

+STUDY REFERENCE

Mertens M, Meert L, Struyf F, Schwank A, Meeus M (2021) Exercise therapy is effective for improvement in range of motion, function and pain in patients with frozen shoulder: a systematic review and meta-analysis. Archives of Physical Medicine and Rehabilitation.

SUPPORTING REFERENCE

1. Bunker TD. Frozen shoulder: unravelling the enigma. Ann R Coll Surg Engl 1997;79(3):210-3.
2. Shaffer B Tibone JE Kerlan RK. Frozen shoulder. A long-term follow-up. J Bone Joint Surg Am. 1992; 74: 738-746
3. White D, Choi H, Peloquin C, Zhu Y, Zhang Y. Secular trend of adhesive capsulitis. Arthritis Care Res (Hoboken) 2011;63(11):1571-5.
4. Prodromidis AD, Charalambous CP. Is There a Genetic Predisposition to Frozen Shoulder?: A Systematic Review and Meta-Analysis. JBJS Rev 2016;4(2).