Stiff posterior capsule? Maybe not...

It is common practice for physical therapists to include an assessment of the posterior glenohumeral joint capsule in patients with shoulder pain. The rationale is that a tight posterior capsule may exert a "Diablo" effect on the proximal humerus and reducing the subacromial space. This is further substantiated by the obeservaton that GIRD (Glenohumeral Internal Rotation Deficit) often seen in throwing athletes is due to limitations of the posterior capsule. These two clinical observations form the rationale for stretching and mobilizing the posterior joint capsule.

However, there is recent evidence that questions whether the posterior capsule is truly responsible for the limitations in internal rotation commonly seen in our patients. A case report by Poser and Casonato in the Journal of Manual Therapy examined a 42 y/o male with a 12 week history of shoulder pain. This patient was the "classic" impingement case. No cervical pathology was identified and there was no evidence of capsular involvement. The primary findings were positive Hawkins and Yocum's testing along with painful resisted abduction.

Internal rotation was measured using electrogoniometry at 90 degrees of abduction. Additionally, a dynamometer was used to measure abduction force. The patient's pain levels were recorded during the pre-treatment testing. The treatment consisted only of soft tissue massage to the infraspinatus (7 minutes) and teres minor (3 minutes). The patient was positioned in a manner as to avoid any tension placed on the posterior capsule. No other treatments including or activity modifications were given.

After three treatment sessions, internal rotation improved from 68 degrees to 88 degrees and all impingement signs were nearly abolished. The authors concluded that reductions in internal rotation often seen with impingement syndrome may not be attributable to posterior capsular tightness. An alternative theory may be that shoulder pain induces a dysfunction of the posterior glenohumeral muscle musculature.

I must admit am a "mobilizer of the posterior capsule". However after reading this case report and using a bit of reasoning, I realize there may be a better explanation for loss of internal rotation we see in our patients. Although this is but one case report, it certainly made me realize I can never get too comfortable with a particular approach or conclusion. I'm not entirely ready to let go of the possibility that the posterior capsule plays a role in shoulder impingement. However, I imagine with further anatomical and histological of this area will confirm my suspicions that there are other mechanisms at play.

A POSER, O CASONATO (2008). Posterior glenohumeral stiffness: Capsular or muscular problem? A case report Manual Therapy, 13 (2), 165-170 DOI: 10.1016/j.math.2007.07.002