Long-Term Radiographic Changes in Stemless Press-Fit Total Shoulder Arthroplasty.

INTRODUCTION: Stemmed humeral implants have represented the gold standard in total shoulder arthroplasty (TSA) for decades. Like many other joints, the latest trends in TSA designs aim at bone preservation. Current studies have demonstrated that native proximal humeral bone stresses are most closely mimicked by stemless implants. Nevertheless, there are concerns about the long-term performance of stemless designs. The aim of the present study was to evaluate the long-term radiographic changes at the proximal humerus in anatomical stemless press-fit TSA. MATERIALS AND METHODS: Between 2008 and 2010, 48 shoulders in 43 patients were resurfaced using an anatomic stemless shoulder prosthesis (TESS, Biomet). Thirty shoulders in twenty-five patients who were aged 65.7 ± 9.9 (34 to 82) years were available for clinical and radiographic review at a mean follow-up of 94.0 ± 8.9 (78 to 110) months. RESULTS: Radiographic changes of the proximal humerus due to stress shielding were found in 38.4% of the stemless TESS implants. Mild stress shielding accounted for 80% of the observed radiographic changes. Radiographs exhibited stable fixation of the stemless humeral press-fit implant at early and late follow-up. In contrast, radiolucent lines at the glenoid implant were found in 96.1% of the cases. Irrespective of the degree of radiographic changes, clinical scores (VAS, Quick-DASH, Constant score) significantly improved at follow-up. CONCLUSIONS: The anatomic stemless press-fit implant seems to be favorable in terms of implant-related stress shielding. Clinical outcome was not affected by radiographic changes, demonstrating an 8-year clinical performance that seems to be comparable to conventional stemmed TSA.

Long-term results of the reverse Total Evolutive Shoulder System (TESS).

INTRODUCTION: Latest trends in shoulder replacement aim at bone stock preservation. Long-term results of stemless anatomical total shoulder implants compare favourably with stemmed designs in terms of function and survivorship. The Total Evolutive Shoulder System (TESS) has been one of the first designs offering a stemless implant not only for anatomical but also for reverse total shoulder arthroplasty with optional short stem attachment in cases with poor bone quality. The aim of the present study was to evaluate long-term results of the reverse Total Evolutive Shoulder System (TESS). MATERIALS AND METHODS: Between 2006 and 2009, 49 shoulders in 47 patients were replaced using the Biomet reverse Total Evolutive Shoulder System (TESS). 29 shoulders in 27 patients who were aged 72.4 ± 6.7 (53-88) years were available for review at a mean follow-up of 101.6 ± 24.6 (75-142) months. RESULTS: The implant survival rate was 93.1% at 101 months (8.4 years). The overall revision rate of the TESS implant was 17.2%. No implant associated complications to the reverse corolla implant could be observed. All reverse corolla implants showed solid fixation at follow-up. Scapular notching was found in 72.3% of the shoulders. Clinical scores significantly improved at long-term follow-up (VAS from 7.5 ± 1.2 to 1.4 ± 1.5, p < 0.001; quick-DASH from 70.9 ± 12.0 to 28.9 ± 22.9, p < 0.001 and Constant score from 13.0 ± 3.7 to 60.5 ± 16.8, p < 0.001). CONCLUSIONS: In terms of clinical scores, radiographic loosening, complication rates and implant survivorship the reverse Total Evolutive Shoulder System provides results comparable to those of conventional stemmed reverse shoulder arthroplasty.

Determination of humeral inclination in stemless shoulder arthroplasty using plain radiographs.

Plain radiographs of the shoulder are routinely used to assess implant orientation after shoulder arthroplasty. Recently, humeral inclination has come into focus especially in reverse stemless shoulder arthroplasty. But, in X-ray projections not exactly parallel to the base of the humeral component, the humeral inclination angle cannot be determined precisely. Therefore, we established a mathematical algorithm to calculate the humeral neck shaft angle and counterchecked the formula using plain radiographs of a sawbone model containing a humeral head prosthesis. With increasing angles of retroversion, the base of the humeral component forms an ellipse in plain radiographs. Knowing the width and length of the ellipse as well as the inclination angle in a plain radiograph, the exact inclination angle can be determined using the equation reported below. Thus, independent from the viewing angle or angle of retroversion, the inclination angle of a stemless humeral head implant can be estimated with an accuracy of ±1.5-degree deviation. The algorithm proposed may be the basis for further research on the impact of humeral inclination in stemless shoulder arthroplasty.

Long-term survivorship of stemless anatomical shoulder replacement.

PURPOSE: Like in many other joints, current shoulder replacement designs aim at bone preservation. According to the literature available, stemless total shoulder arthroplasty (TSA) compares favourably with stemmed designs in terms of function and survivorship of the implant. However, long-term results of stemless shoulder arthroplasty are still missing. Therefore, the aim of the present study was to evaluate long-term results of stemless anatomical TSA. METHODS: Between 2006 and 2009, 51 shoulders in 46 patients were resurfaced using the Biomet Total Evolutive Shoulder System (TESS). Thirty-one shoulders in 26 patients who were aged 66.7 ± 10.0 (range 34-82) years were available for review at a mean follow-up of 94.7 ± 11.3 (76-124) months. RESULTS: The implant survival rate was 93.5% at eight years. The overall revision rate of the TESS implant was 9.7%. Radiolucent lines were found on the glenoid side of the TESS arthroplasty in 90.9% of the cases. All stemless humeral corolla implants showed solid fixation at follow-up. Clinical scores significantly improved at long-term follow-up (VAS from 8.1 ± 0.9 to 1.0 ± 1.2, p < 0.001; Quick-DASH from 67.9 ± 13.5 to 18.7 ± 16.5, p < 0.001 and Constant score from 14.7 ± 6.1 to 68.8 ± 13.2, p < 0.001). CONCLUSIONS: Stemless TSA has stood the test of time at eight years in terms of clinical scores, radiographic loosening, complication rates and implant survivorship.