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Background The re-tear rate after supraspinatus tendon (SSP) repair is high despite optimization of surgical techniques. The critical shoulder angle (CSA) > 35° has been identified as a risk for re-tear. Surgical reduction of the CSA performing additional lateral acromioplasty (ALAP) is intended to reduce the risk. Objective We aimed to evaluate the effect of ALAP on the re-tear rate in patients with a CSA > 35° after SSP repair. Patients and methods The study included 49 shoulders fulfilling predefined inclusion criteria. The patients were assigned to two groups; group I (25 SSP) was additionally treated with an ALAP. In group II (24 SSP) standard acromioplasty was performed during reconstruction. Magnetic resonance imaging and a clinical examination (Constant Score; CS) were performed 12 months after surgery. Results After 15 months group I showed a re-tear rate of 20%, a decreased CSA (mean 38.0° preoperatively vs. 34.5° postoperatively) and an increase in CS (mean 53.9 vs. 84.6). After 16 months group II showed a re-tear rate of 16.7%, no difference between pre- and postoperative CSA (37.8° vs. 37.6°), and an increase in CS (48.9 vs. 84.5). There was no difference between the groups in terms of re-tears and postoperative CS (p = 0.4557), but there was a significant difference in postoperative CSA (p 35° did not have a worse clinical outcome and no increased rate of re-tears compared with patients with a mechanically reduced CSA. Conclusion Additive lateral acromioplasty does not decrease the re-tear rate after arthroscopic SSP repair. However, ALAP significantly decreases the CSA to normal values.

Background The clinical and radiographic results of an all-polyethylene glenoid with variable backside curvature adapted to the individual anatomy were compared with a standard all-polyethylene glenoid. Methods This retrospective study included 87 patients with primary glenohumeral osteoarthritis and anatomic shoulder replacement with a short-stem prosthesis and cemented all-polyethylene glenoid. In all, 42 patients with a mean age of 67 ± 8 years were treated with an all-polyethylene glenoid without variable curvature (group 1) and 45 patients with a mean age of 68 ± 10 years were treated with an all-polyethylene glenoid with individualized curvature (group 2). Clinical outcome was determined by range of motion, Constant Score (CS) age- and sex-adjusted Constant Score (CS%), and Subjective Shoulder Value (SSV). Radiographs were analyzed for the occurrence of radiolucent lines according to the method of Mole. Results After a mean follow-up of 31 months (range, 24–50) a significant improvement was achieved in all clinical parameters in both groups (p p = 0.713). At the final follow-up, the radiolucent line scores were 1.2 ± 2.0 in group 1 and 0.9 ± 1.1 in group 2 (p = 0.410). In five patients (12%) from group 1 and four patients from group 2 (9%), the radiolucent line score increased over time. One patient in group 1 (2%) exhibited radiographic glenoid loosening. Conclusion The all-polyethylene glenoid with individualized curvature showed promising short-term clinical and radiographic results. Further studies with a longer follow-up are necessary to evaluate whether the new all-polyethylene glenoid is superior to the standard all-polyethylene glenoid.

Partial circulatory support is a promising concept for the treatment of heart failure patients. A better understanding of induced hemodynamic changes is essential for optimizing treatment efficacy. Computational fluid dynamics (CFD) is an alternative method to gain insight into flow phenomena difficult to obtain in vivo. In 10 patients implanted with a Circulite Synergy Micro-pump (HeartWare, Framingham, Massachusetts) (a continuous flow partial circulatory assist device connecting the left atrium to the right subclavian artery), transient CFD simulations were performed. Patients were divided into two groups depending on their cardiac output (CO; high CO group: 5.5 ± 1.1 L/min, low CO group: 1.7 ± 0.7 L/min). The partial assist device provided a supporting flow of 1.5 ± 0.8 L/min. Support was highest at diastole and decreased during systole because of a collision of the blood flows from the partial assist device and the CO. Reversed flow counteracting the flow of the device was significantly higher for the high CO group (mean flow in peak systole: -2.18 ± 1.08 vs. 0.23 ± 0.59 L/min; p = 0.002) showing an inverse correlation between CO and amount of reversed flow during peak systole (R = -0.7; p < 0.02). The flow collision lead to higher total pressures at the point of collision and consequently in the Circulite outflow graft. The CFD simulations allow quantifying hemodynamic alterations in patients with partial support consisting of a flow collision, thereby reducing effectiveness of the circulatory support. Partial support in heart failure patients alternates their hemodynamics not only in providing support for the circulation but also inducing unfavorable changes in flow patterns.