Background and purposeDespite good clinical results with the reverse total shoulder arthroplasty, inferior scapular notching remains a concern. We evaluated 6 different solutions to overcome the problem of scapular notching.MethodsAn average and a “worst case scenario” shape in A-P view in a 2-D computer model of a scapula was created, using data from 200 “normal” scapulae, so that the position of the glenoid and humeral component could be changed as well as design features such as depth of the polyethylene insert, the size of glenosphere, the position of the center of rotation, and downward glenoid inclination. The model calculated the maximum adduction (notch angle) in the scapular plane when the cup of the humeral component was in conflict with the scapula.ResultsA change in humeral neck shaft inclination from 155° to 145° gave a 10° gain in notch angle. A change in cup depth from 8 mm to 5 mm gave a gain of 12°. With no inferior prosthetic overhang, a lateralization of the center of rotation from 0 mm to 5 mm gained 16°. With an inferior overhang of only 1 mm, no effect of lateralizing the center of rotation was noted. Downward glenoid inclination of 0º to 10º gained 10°. A change in glenosphere radius from 18 mm to 21 mm gained 31° due to the inferior overhang created by the increase in glenosphere. A prosthetic overhang to the bone from 0 mm to 5 mm gained 39°.InterpretationOf all 6 solutions tested, the prosthetic overhang created the biggest gain in notch angle and this should be considered when designing the reverse arthroplasty and defining optimal surgical technique.

The reverse total shoulder prosthesis provides successful functional outcome in many patients with rotator cuff tear arthropathy. However, scapular notching, a direct consequence of mechanical impingement between the humeral prosthesis and the glenoid, remains a major concern. We presumed a better knowledge of the anatomy of the scapula would enable design or placement modifications to minimize this phenomenon. After establishing a uniform spatial reference system using easy locatable surgical reference points and planes, we analyzed 200 dry bony scapulae and defined the glenoid and infraglenoid anatomy relative to the reference system. The bony rim of the two inferior quadrants of the glenoid forms a semicircle the center of which can be used perioperatively as an easy locatable bony reference point. The infraglenoid tubercle varies in width and length, and can interfere with the humeral part of the reverse prosthesis, creating scapular notching. To avoid notching, we suggest using a convex base plate with a smaller radius than currently used, placing it as low as possible with a 42-mm glenosphere eccentrically assembled to create a posterior offset. If prosthetic overhang cannot be obtained, we suggest removing part of the infraglenoid tubercle.

We discovered a numerical mistake in the total number and type of prostheses and subsequently wrongfully concluded a partial disengagement occurred in 45.4% of the Aequalis TM prostheses when in fact the rate was much lower. We wish to correct our report. We hope an adjustment can be made and we apologize for any inconvenience we have caused.We reviewed 396 patients with 407 reverse shoulder arthroplasties (342 Delta III

BackgroundThis study evaluates the preoperative conventional anteroposterior radiography and clinical testing in non-operated patients with cuff tear arthropathy. It analyses the radiological findings in relation to the status of the rotator cuff and clinical status as also the clinical testing in relation to the rotator cuff quality. The aim of the study is to define the usefulness of radiography and clinical examination in cuff tear arthropathy.MethodsThis study analyses the preoperative radiological (AP-view, (Artro-)CT-scan or MRI-scan) and clinical characteristics (Constant-Murley-score plus active and passive mobility testing) and the peroperative findings in a cohort of 307 patients. These patients were part of a multicenter, retrospective, consecutive study of the French Orthopaedic Society (SOFCOT-2006). All patients had no surgical antecedents and were all treated with prosthetic shoulder surgery for a painful irreparable cuff tear arthropathy (reverse-(84%) or hemi-(8%) or double cup-bipolar prosthesis (8%)).ResultsA positive significancy could be found for the relationship between clinical testing and the rotator cuff quality; between acromiohumeral distance and posterior rotator cuff quality; between femoralization and posterior rotator cuff quality.ConclusionA conventional antero-posterior radiograph can not provide any predictive information on the clinical status of the patient.The subscapular muscle can be well tested by the press belly test and the teres minor muscle can be well tested by the hornblower' sign and by the exorotation lag signs.The upward migration index and the presence of femoralization are good indicators for the evaluation of the posterior rotator cuff.An inferior coracoid tip positioning suggests rotator cuff disease.