Multidirectional instability (MDI) of the glenohoumeral (shoulder) joint is symptomatic subluxation or dislocation occurring in two or three directions. It is thought to be due as a result of repetitive microtrauma on a background of a congenitally lax shoulder capsule. The shoulder joint can be thought of as trying to balance a beach ball (head of humerus) on a golf tee (the socket). Therefore stability is largely reliant on muscles, ligaments and the capsule. Patients with MDI have been shown to have reduced muscle strength and control compared to those who do not. Therefore if stability isn’t coming from shoulder muscles, ligaments and capsules, then microinstability can occur.
Symptoms will range from mild reports of pain to apprehension, impingement, rotator cuff pain and neuro-related symptoms. People may report a history of traumatic or atraumatic subluxations and dislocations and a general feeling of ‘instability’.
The starting point for most MDI cases is a thorough rehabilitation program. With a focus on strengthening around the scapula (shoulder blade) and rotator cuff muscles. It is hoped that by strengthening the shoulder muscles that it will assist in active control of the shoulder and negate the loss of passive stability (the lax capsule). Strength work is usually started in a position that is easy to control (by the side of the body) and eventually progress to more challenging positions (overhead activities). Treatment for this condition will often take between 3 and 6 months depending on patient presentation and past history.
If exercise therapy is not successful, occasionally surgical intervention is required to tighten the ligament capsule.
Reference: The treatment of mutlidirectional instability of the shoulder with a rehabilitation program: Part 1 Watson et al 2016.
To make a booking to see your local Melbourne physiotherapist for treatment of shoulder instability issue or MDI, please call either the Essendon, North Melbourne or Blackburn physiotherapy clinics or book online.