RESUMO
AIM: To evaluate the joint geometry and the clinical outcome of stemless, anatomical shoulder arthroplasty with the TESS system. METHODS: Twenty-one shoulders with a mean follow-up 18 of months were included. On scaled digital radiographs the premorbid center of rotation (CoR) was assessed and compared to the CoR of the prosthesis by using the MediCAD® software. Additionally, the pre- and post-operative geometry of the CoR was assessed in relation to the glenoid, the acromion as well as to the proximal humerus. Radiological changes, such as radiolucencies, were also assessed. Clinical outcome was assessed with the Constant and DASH score. RESULTS: Both, the Constant and DASH scores improved significantly from 11% to 75% and from 70 to 30 points, P < 0.01 respectively. There were no significant differences regarding age, etiology, cemented or metal-backed glenoids, etc. (P > 0.05). The pre- and postoperative humeral offset, the lateral glenohumeral offset, the height of the CoR, the acromiohumeral distance as well as neck-shaft angle showed no significant changes (P > 0.05). The mean deviation of the CoR of the prosthesis from the anatomic center was 1.0 ± 2.8 mm. Three cases showed a medial deviation of more than 3 mm. These deviations of 5.1, 5.7 and 7.6 mm and were caused by an inaccurate humeral neck cut. These 3 patients showed a relatively poor outcome scoring. CONCLUSION: TESS arthroplasty allows an anatomical joint reconstruction with a very good outcome. Outliers described in this study sensitize the surgeon for an accurate humeral neck cut.
RESUMO
INTRODUCTION: The aim of this study was to evaluate the clinical and radiological outcome of the Total Evolutive Shoulder System (TESS) in patients with cuff tear arthropathy and patients in need of a revision arthroplasty. METHODS: In this sequential study, 67 patients (56 non-stemmed, 11 stemmed) were evaluated after a mean follow-up of 17.5 months. The relative Constant and DASH scores, radiological joint geometry changes, complications and postoperative problems, which are not likely to affect the outcome, were evaluated. RESULTS: A significant increase was noticed for the relative Constant (11.3 vs. 78.8 %) and DASH scores (73.7 vs. 31.8) without significant differences between both etiology groups. Complication rates were similar to previous studies. An aseptic loosening of the non-stemmed humeral component was not noticed in the cuff tear arthropathy group, whereas one case with a loosening was noticed in the revision arthroplasty group. With nine cases (13.4 %), scapular notching rates were very low. On average, the acromiohumeral distance increased by 17 mm and the humeral offset by 13.9 mm; the height of the center of rotation decreased by 4.6 mm and the lateral glenohumeral offset by 6.1 mm, p < 0.05, respectively. CONCLUSION: Regarding the joint geometry, surgery with the TESS system provided adequate distalization and medialization of the humerus and the center of rotation. This corresponds to a good clinical outcome. The use of the surgical opportunity to implant the prosthesis with a relatively low neck-shaft angle might explain the low rates of scapular notching in our series. Regarding the case with a loosening of the humeral component, the surgeon should carefully indicate a stemless version for metaphyseal press-fit fixation in patients with revision arthroplasty.
