Wednesday, November 2, 2016

Reverse total shoulder - subscapularis repair and Pooh corner

Comparison of reverse total shoulder arthroplasty outcomes with and without subscapularis repair

These authors reviewed 340 patients having  reverse total shoulder arthroplasty with a subscapularis repair and 251 having reverse total shoulder arthroplasty without a subscapularis repair. Mean follow-up was 37 months.

All patients showed significant improvements in pain and function after treatment with rTSA.

The complication rate was 7.4% (0% dislocations) for the subscapularis-repaired cohort and 6.8% (1.2% dislocations) for the non–subscapularis-repaired cohort.

Comment: It is unclear why some shoulders had the subscapularis repaired and others did not. In some cases the subscapularis may have been irreparable or so short that repair would have excessively limited motion. It is also possible that the particular surgeon had theoretical reasons for not repairing the tendon, such as the belief that the repaired subscapularis may overpower weakened external rotators or that it may apply an adduction force acting in opposition to the deltoid. It would have been helpful to know the reasons for subscapularis repair or non repair.

Our practice is to repair the subscapularis when possible to improve stability and proprioception.

These authors also provide a comparison of different prosthetic designs. In their diagram below, we've added an arrow to the point where the humeral polyethylene may contact the bone of the scapula. One can see the different amounts of clearance for the different designs.

 Such contact may cause poly deformation and debris, instability and pain as discussed in this link.

 We refer to the area between the proximal humerus and the lateral scapula as "Pooh Corner" and are sure to check for the absence of contact in each of our primary or reverse total shoulder arthroplasties.