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Techniques-Glenoid Bone Deficiency

Although osteoarticular pathology rarely is a cause of anterior instability, it is essential that it be ruled out prior to proceeding with any soft-tissue stabilization procedure or in the revision setting. A small subset of patients may be predisposed to instability due to developmental glenoid dysplasia, or pathologic flattening or hypoconcavity of the glenoid as well as abnormal glenoid version.

More commonly, significant loss of normal glenohumeral bony anatomy is the result of traumatic dislocation or recurrent episodes of instability. The anterior glenoid rim can actually become rounded and flattened from recurrent dislocations. Experience has shown that when such defects are present there is an increased risk of failure when only soft-tissue repairs are performed.

Burkhart and DeBeer, for example, noted that in patients with recurrent anterior instability treated arthroscopically, there was a recurrence rate of 4% in subjects with normal bony anatomy compared to 67% in those with significant bony defects.

Fortunately, many surgeons now recognize the need to reconstruct or compensate for anterior or posterior glenoid bone loss by open methods. The surgical options include either an anatomic reconstruction of the glenoid with bone graft or a coracoid process transfer, such as the Bristow or Latarjet procedures. The authors use the patient’s symptoms and Gerber’s biomechanical work to form a framework under which glenoid bone grafting is considered . If

(a) the patient has recurrent instability, particularly with mid-range symptoms;
(b) if the patient has symptoms of instability during sleep, or with decreasing degrees of trauma;
(c) if a bone defect is seen on x-ray;
(d) or if the patient has failed a prior arthroscopic procedure;

a CT scan is obtained. If the CT scan demonstrates an osseous defect that is longer in the saggital plane than the maximum radius of the glenoid, then an anatomic glenoid reconstruction is performed.

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