Multidirectional instability is characterized by recurrent atraumatic instability of the glenohumeral joint due to a lax joint capsule.
It is more common in young female patients less than 30 years of age.
Multidirectional instability is due to congenital laxity of the joint capsule. It is atraumatic and commonly bilateral. Poor coordination of the rotator cuff muscles contributes to the worsening of laxity. In some cases it may have psychiatric cause with subjective symptoms which is not relieved by surgery. There is a positive family history in a minority of cases with genetic abnormal collagen production or cross-linking; e.g. Marfan or Ehlers Danlos syndrome.
Usually, there is no abnormality of the labrum, ligaments or tendons, or evidence of previous shoulder dislocation is present. However, gradually the longterm sublaxation results in labral injury and rotator cuff impingement.
Some of the possible radiologic findings are:
- hypoplastic glenoid fossa
- retroversion of the glenoid
- small labrum
- generalized joint laxity
Treatment is mainly rehabilitation; if surgery required then tightening of the inferior capsule and rotator interval may prove helpful.
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