Midterm clinical outcome of uncemented short-stem reversed shoulder arthroplasty.

INTRODUCTION: While the incidence of reverse total shoulder arthroplasty (rTSA) is increasing constantly, newer implants with designs other than the classic Grammont geometry are gaining importance. More anatomic inclination angles and lateralization are supposed to have a positive impact on clinical results and complication rates. Presentation of midterm results therefore is important to support these assumptions. The aim of this study was to report the midterm clinical outcome of primary rTSA with an uncemented humeral short-stem prosthesis (USSP) with a humeral inclination angle of 145° and the analysis of different variables on the outcome. METHODS: This is a retrospective study of all patients with primary rTSA using an USSP and a combined humeral inclination angle of 145° (Ascend™ flex, Stryker) with a minimum clinical follow-up of 2 years. The implant combines a 132.5° inclination for the humeral stem with an additional 12.5° for the polyethylene inlay. Primary outcomes were patient-reported outcome measures: ASES score, simple shoulder test (SST) and subjective shoulder value (SSV). Secondary outcomes were complication and revision rates. We analyzed different variables: preoperatively gender, age, indication for surgery and status of rotator cuff. Also, the glenoid morphology was classified according to Walch and a proximal humerus cortical bone thickness measurement (CBT avg) of 6 mm was used as a threshold for osteoporosis. Postoperatively, we analyzed different radiologic parameters: filling ratio, distalization and lateralization angles according to Boutsiadis. RESULTS: A total of 84 out of 99 (85%) patients with a mean FU of 46.7 months (range 24-80 months) could be included: 62 women and 22 men with a mean age of 74.7 years. Mean ASES score significantly increased from 47 preoperatively to 85.8 at the last follow-up (p = 0.001). The postoperative SST reached an average of 65.3 and the mean SSV was 83%. None of the variable parameters analyzed could be identified as a risk factor for a lower outcome defined as a SSV < 70. Three patients (3.6%) had a complication: one incomplete lower plexus lesion, one dislocation and one major hematoma. Surgical revision was needed in two cases (2.4%). CONCLUSION: The midterm clinical outcome of primary reverse total shoulder arthroplasty (rTSA) with an uncemented humeral short stem and a humeral inclination angle of 145° showed good-to-excellent results with a low complication and revision rate independent from a wide range of pre- and postoperative variables. PROMs are comparable to those reported for anatomic TSA with a low complication rate, different to historical studies especially with the Grammont design. LEVEL OF EVIDENCE: Treatment study, Level IV.

Standard radiological classification of glenohumeral osteoarthritis does not correlate with the complexity of the arthritic glenoid deformity.

BACKGROUND: The Samilson-Prieto classification (SPC) depending on the humeral osteophyte length on a-pX-rays today is widely used to classify glenohumeral osteoarthritis in general. For treatment planning and prognosis, the patho-morphology of the glenoid and static posterior subluxation of the humeral head classified according to Walch is of much higher importance. Here, usually a CT or MRI scan is required for a correct classification. A possible correlation between both classifications is poorly explored. Without it, the complexity of the case might be mis-interpreted using the SPC. The aim of this study was to investigate such a correlation, i.e. whether it correlates with the glenoid deformity and degree of humeral head subluxation. PATIENTS AND METHODS: Radiological datasets (X-ray and CT or MRI) of 352 patients with primary OA of the shoulder were evaluated by two observers experienced in shoulder surgery. For the Samilson-Prieto classification, true a-p shoulder radiographs and for the modified Walch classification CT or MRI scans in the axial plane were interpreted using a validated method. To investigate a correlation between both classifications, the Fisher's exact test was used. For the interobserver reliability, the weighted kappa coefficient κ was determined. RESULTS: For the Walch classification, both observers found a similar percentage for the different types, with decreasing numbers from normal (type A1) to severely altered glenoids In the Samilson-Prieto classification, OA grade I was predominant, while grade II and III showed a relatively equal distribution. Interobserver reliability was high both for the Walch classification with a κ 0.923 (95% confidence interval 0.892; 0.954) and) for the SPC with a κ 0.88 (95% confidence interval 0.843; 0.916). A correlation between the two classifications in Fischer's exact test could not be shown (p = 0.584). DISCUSSION: Since there is no correlation between both, using the Samilson-Prieto classification alone might miss relevant prognostic factors in gleno-humeral OA. Adequate imaging of the glenoid morphology also in the axial plane is absolutely mandatory to understand the complexity and chose the right treatment for each patient. LEVEL OF EVIDENCE: Study of Diagnostic Test-Level II.

Arthroscopic findings in atraumatic shoulder instability.

PURPOSE: The goal of this study was to evaluate the intra-articular pathology in patients with atraumatic shoulder instability who did not respond to conservative treatment. TYPE OF STUDY: Prospective case series. METHODS: Of 226 patients treated for shoulder instability over a 2-year-period, 43 patients (average age, 27.5 years; 26 men and 17 women) were classified as having atraumatic instability. None had responded to physiotherapy. The intra-articular pathology was documented during diagnostic arthroscopy before the definitive surgical procedure. RESULTS: Three types of lesions of the capsulolabral complex were defined: incomplete labral lesions, pathologic elongation of the capsule or "non-Bankart lesions" (type I), classic Bankart lesions (type II), and complex lesions of the labrum and capsule (type III). Type I was found in 19 patients (44.2%); type II lesions were seen in 13 (30.2%); and type III in 11 (25.6%) patients. Hill-Sachs lesions were found in 26 shoulders (60.5%). Chondral lesions of the glenoid were seen in 10 shoulders (23%); SLAP lesions in 5 (11.7%); and partial, articular-side defects of the supraspinatus tendon in 3 (6.9%) patients. CONCLUSIONS: Atraumatic onset of shoulder instability does not imply the absence of intra-articular lesions, at least in patients not showing a response to physiotherapy. Arthroscopy is helpful to diagnose the definite intra-articular pathology. LEVEL OF EVIDENCE: Level IV.