Saturday, January 26, 2013

Glenoid component in total shoulder - perforation

Perforation tolerance of glenoid implants to abnormal glenoid retroversion, anteversion, and medialization.

The authors opine that it is important to avoid perforating the glenoid vault during insertion of the glenoid implant. To our knowledge, it has not been demonstrated that perforation predisposes the glenoid component to failure. What does predispose the glenoid to failure, as discussed in previous posts, is poor contouring of the underlying bone, poor cement technique, excessive reaming that removes supporting bone, and failure to balance the humeral head on the glenoid.

The authors made 3-dimensional models of 15 glenoid implants and and virtually implanted into 3-dimensional reconstructed models of 40 nonarthritic scapulae. It is of importance to note that the pathoanatomy of arthritic glenoids is quite different from 'nonarthritic scapulae' so the clinical relevance of the findings is unclear.

They found that the overall mean increased retroversion tolerated before perforation was 19°, increased anteversion was 16°, and abnormal version fully corrected by eccentric reaming was 17°.
It is furthermore of interest that the average glenoid retroversion in reported series of patients with arthritis is between 8 and 27 degrees Would it be better in the cases with more than 17 degrees of retroversion to (a) avoid using a glenoid component, (b) ream to normalize the version anyway, or (c ) accept the retroversion and use soft tissue balance to stabilize the joint?

In each patient the surgeon has many choices to make, including whether or not to insert a glenoid component, which glenoid component to use, how to manage the tradeoff between reaming and contouring and change of glenoid orientation. In our practice, 'perforation' of the fixation pegs is a minor concern, subordinate to the contouring of the glenoid surface, preservation of glenoid bone stock and good cement technique. Our approach is summarized here.

Use the "Search" box to the right to find other topics of interest to you.

You may be interested in some of our most visited web pages including:shoulder arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery.

See from which cities our patients come.

See the countries from which our readers come on this post.