The prognostic factors which affect on the radiologic and functional midterm results in the reverse shoulder arthroplasty

Background: Reverse shoulder arthroplasty (RSA) indications are expanding. Although first design for shoulder with cuff tear arthropaty (CTA). Our purposeses of study are evaluate the mid-term clinical and radiological results with two different biomechanical design prosthesis. Determine the prognostic factors that usable for follow-up period and analyze the effects on clinical outcome with these two different design. Methods: At a minimum of two years postoperatively, 65 RSAs (43 CTA, 14 acute fracture, 4 revision, 2 fracture sequele and 2 instability) with a mean 71,9 age and 33.5 months follow-up were evaluated. All patients' clinical outcomes are classified by Neer Criteria as excellent, satisfied and unsatisfied. And postop ROM, scoring systems (Constant, ASES, Q-DASH, VAS and SF-12) and radiographically with the prosthesis scapular neck angle (PSNA), peg glenoid rim distance (PGRD), overhang distance, acromion-tuberosity distance (AT) and glenoid-tuberosity distance (GT) on the development of inferior scapular notching and clinical outcome were assessed biostatistically and compare with clinical outcomes for the all cases. Two different prosthesis (medialized and lateralized) was used. Also we measure the humerus lengthening and greater tuberosty healing for acute fracture group for compere with outcome. Results: Excellent or satisfactory results according to Neer's criteria were obtained in 76,9% and %23,1 unsatisfactory results. The PSNA values was directly correlated to the excellent and satisfactory group. The cutoff point for the PSNA with general outcome correlation was calculated as 114° for satisfactory, 105° for excellent clinical outcome group using ROC curve analysis. In CTA group, scapular notching rate was reported % 70,7 and this rate was significantly correlated with PSNA, PGRD and overhang values (p=0,001). In addition the external rotation of non-medialized group was significantly better than the lateralized ( 42° vs 30° p:0.039). Conclusion: Postoperative PSNA values are predictive for clinical outcomes of TSA. And in CTA cases, PSBA, PGRD and overhang distance can bu use for the predictive factors for formation of scapular notching. Also non-medialized prosthesis results, increase the patients' and also surgeons satisfaction through the greater postoperative rotation capability.