Effects of high-intensity laser therapy among patients with frozen shoulder: A quasi-experimental study

The purpose of this study was to assess the effects of HILT on pain levels, shoulder flexion [FLEX], abduction [ABD], external rotation [ER] and internal rotation [IR] range of motion (ROM) and shoulder functions in patients with frozen shoulder (FS). 

Thirty patients with FS were divided into two groups: an active group (HILT and exercise therapy, n =15) and a control group (ultrasound therapy and exercise therapy, n = 15). All patients were clinically diagnosed with FS by a medical doctor. The treatment was administered in 3 sessions over 5 weeks (1^st, 3^rd and 5^th weeks). The main outcome measures such as the evaluation of severity of pain by visual analogue scale (VAS) and shoulder FLEX, ABD, ER and IR ROM measurements by digital goniometry, were done at baseline, 3 and 5 weeks after the treatment. Shoulder pain and disability index (SPADI) was measured at baseline and after 5 weeks to evaluate pain and disability associated with FS.

Both groups showed significant changes of VAS scores within group for immediate and long term effect (p 0.001). However, HILT plus exercise demonstrated a higher percentage of change for the immediate effect in comparison to control group plus exercise (30.91% vs 18.95%) as well as for long term effect (64.91% vs 50.07%). A repeated measures (RM) ANOVA indicated a statistically significant reduction of pain levels over time (baseline, 3^rd week and 5^th week) with p = 0.023 for both group.  

For shoulder ROM, there were statistically significant immediate and long term effects for all of the movements (p 0.001) in both groups, with active group showed more percentages of change. A RM ANOVA indicated a statistically significant changes in shoulder FLEX, ABD, ER and IR ROM over time (baseline, 3^rd week and 5^th week) with p 0.001. There was significant difference  in shoulder FLEX, ER and IR ROM between the two groups (p 0.001)  except shoulder ABD (p = 0.211) and significant interaction between time and treatment group for all movements (p 0.001). 

For shoulder function, there was significant improvement in SPADI pain, SPADI disability and SPADI total score within both groups in the final follow up (p 0.001), with active group showed a higher percentage of change compared to control group.

Both HILT plus exercise and US therapy plus exercise are effective  in reducing pain, increasing ROM and promoting shoulder function in individuals with FS, however HILT plus exercise is superior than US plus exercise. These findings indicate that HILT should be regarded as a preferable treatment method for FS in clinical practice.

These findings support the integration of HILT into FS management protocols to optimise patient outcomes and improve quality of life.