Effect of Scapular Movement Training on Pressure Pain Threshold, Pectoralis Minor Length, Scapular Dyskinesis and Shoulder Function in Adhesive Capsulitis: A Single Blind Randomized Controlled Trial

Background Adhesive capsulitis is a common painful shoulder condition. Scapular dyskinesis is commonly seen in patients with adhesive capsulitis. Studies suggest that the shortness of pectoralis minor muscle can be responsible for scapular dyskinesis. Scapular movement training is a movement based training system. It has been proved effective in reducing pain and improving function in patients with chronic shoulder pain. Hence, this study is trying to find out the effect of scapular movement training on pressure pain threshold, pectoralis minor length, scapular dyskinesis and shoulder function in adhesive capsulitis.  Purpose To find out the effect of scapular movement training on pressure pain threshold, pectoralis minor length, scapular dyskinesis and shoulder function in adhesive capsulitis.  Materials and Method The randomized controlled trial was conducted on twenty six subjects who were divided into two groups, control and intervention groups. Pressure pain threshold, pectoralis minor length, scapular dyskinesis and shoulder function were assessed using pressure pain algometer, pectoralis minor index, scapular dyskinesis test and shoulder pain and disability index, respectively. Intervention was started after the initial assessment. Both groups performed the intervention 3 times a week for 6 consecutive weeks. Pre scores were taken before the intervention, post scores after 6 weeks and a follow up score after 9 weeks.  Results and Discussion The within group analysis for outcome measures were performed using paired t test for normally distributed data and Wilcoxon signed rank test for non normal data. Between group analysis for outcome measures were performed using independent t test for normally distributed data and Mann Whitney U test for non normal data. The results showed that there is significant effect of scapular movement training on all of the outcome measures (p<0.001, at 95% confidence interval), whereas there is significant long term follow up effect on these outcome measures (p<0.05, at 95% confidence interval) except for pressure pain threshold for levator scapulae and shoulder function. Patients with adhesive capsulitis exhibit improper activation and control of muscles and weakness, resulting in decreased pressure pain thresholds of shoulder muscles. Shortened pectoralis minor muscle is reported to increase scapular dyskinesis by increasing anterior scapular tilt. Both shortened pectoralis minor muscle and altered activation of scapular stabilizing muscles ultimately result in scapular dyskinesis. Scapular focused exercises concentrating on controlled exercise progressions with feedback can help to improve muscle control, re-educate neuromuscular activity, improve motor control and central processing and optimize internal feedback. These mechanisms might have altered the activation patterns and control of the affected muscles like middle deltoid, upper trapezius, levator scapulae, pectoralis minor and other scapular stabilising muscles, resulting in the improvement in pressure pain threshold, pectoralis minor length and scapular dyskinesis in subjects with adhesive capsulitis.  Conclusion Scapular movement training is effective in improving pressure pain thresholds for middle deltoid, upper trapezius and levator scapulae, pectoralis minor length, scapular dyskinesis and shoulder function, and this effect even persists in the follow up period except pressure pain threshold for levator scapulae and shoulder function in adhesive capsulitis.