Reverse shoulder arthroplasty (RSA) is increasingly utilized to restore shoulder function in patients with osteoarthritis and rotator cuff deficiency. There is currently little known about shoulder function after RSA or if differences in surgical technique or implant design affect shoulder performance. The purpose of this study was to quantify scapulohumeral rhythm in patients with RSA during loaded and unloaded shoulder abduction.

Eleven patients with RSA performed shoulder abduction (elevation and lowering) with and without a handheld 3kg weight during fluoroscopic imaging. Three RSA designs were included. We used model-image registration techniques to determine the 3D position and orientation of the implants. Cubic curves were fit to the humeral elevation as a function of the scapular elevation over the entire motion. The slope of this curve was used to determine the scapulohumeral rhythm (SHR).

For abduction above 40°, shoulders with RSA exhibited an average SHR of 1.5:1.

There was no significant difference in SHR between shoulder abduction with and without 3kg handheld weights (1.6±0.2 unweighted vs. 1.4±0.1 weighted), nor was there a significant difference between elevation and lowering. SHR was highly variable for abduction less than 40°, with SHR ranging from a low of 1 to greater than 10. For these very small groups, there was no apparent pattern of differences between implant designs having differing degrees of lateral offset.

At arm elevation angles less than 40°, SHR in RSA shoulders is highly variable and the mean SHR (2–5) with RSA appears higher than SHR in normal shoulders (2–3).

At higher elevation angles, SHR in shoulders with RSA (1.5–1.8) is much more consistent and appears lower than SHR in normal shoulders (2–4). With the small subject cohort, it was not possible to demonstrate differences between subjects with different implant designs. Ongoing analysis of reverse shoulder function with larger cohort sizes will allow us to refine our observations and determine if there are differences in shoulder function due to implant design, preoperative condition and rehabilitation protocols.

This study asseses the biomechanical properties of the Locking Volar T-Plate. It compares the axial load to failure to more traditional plating methods including the T-Plate and Pi-Plate. All three plates were tested for axial load to failure in both a dorsally comminuted model and a highly comminuted model with disruption of both the volar and dorsal cortices. The data in this study indicates may support volar plating for dorsally comminuted distal radius fractures.

The pirpose of this study was to compare the biomechanical properties of three distal radius plates.

The Locking Volar T-Plate performs equally as well regardless of the presence of volar comminution while the other systems do not. It also outperforms both other systems when volar comminution is present.

This study provides biomechanical data of the Volar Locking T-Plate.

Three distal radius plating systems were used on left radii after having either a segmental or dorsal wedge osteotomy performed to simulate severely comminuted and dorsally comminuted distal radius fractures respectively. Group One was plated with an AO stainless steel Pi plate, Group Two with a stainless steel T-plate volarly and Group Three with a stainless steel Locking Volar T-Plate. Specimens in all six of these groups (three groups with each type of osteotomy) were tested in axial loading to determine their load to failure.

The load to failure was significantly higher with the Locking Volar T-Plate than the T-plate (p = 0.001) and Pi plate (p < 0.001) in the severely comminuted model. There was no significant difference between the groups in the dorsally comminuted model. There was no significant difference in the load to failure of the Locking Volar T-Plate between both models and between it’s the load to failure in the severely comminuted model and that of the Pi plate in the dorsally comminuted model.

There has been limited data to date on the Locking Volar T-Plate. Studies, such as this one will provide biomechanical evidence supporting its use.

This study prospectively evaluated the functional outcome and strength of patients after rotator cuff surgery. Thirty-three patients were evaluated pre-operatively and post-operatively for one year. Each patient underwent clinical evaluation of shoulder range of motion and machine strength testing. Additionally they completed the SF-36, DASH, Western Ontario Rotator Cuff, and Washington Simple Shoulder Test questionnaires. The study showed that patients with small and large tears showed improvement after surgery. Smaller tears had better outcomes. Workplace Safety and Insurance Board (WSIB) patients had lower functional outcomes despite strength and range of motion showing no difference with non- WSIB patients.

This study prospectively evaluated strength and functional outcome after rotator cuff surgery.

Thirty-three patients, mean age 55.6, were evaluated pre-operatively and post-operatively for one year. Twenty-eight patients were male and five were female. Seventeen patients involved the Workplace Safety and Insurance Board and sixteen patients had non-WSIB related tears. The patients were also divided based on tear size into two groups (< 3cm and > 3.1cm). Allpatients underwent an acromioplasty. Twenty-two also had an open or mini-open repair. Two underwent arthroscopic repair. Five patients had a debridement and four patients had Latissimus Dorsi Transfer. All had an evaluation of range of motion(ROM), machine isometric strength testing, and completion of the SF-36, DASH, Western Ontario Rotator Cuff (WORC) and Washington Simple Shoulder Test (WST) at each visit.

Based on tear size, there was a significant difference in functional outcome on the SF-36 (p< 0.05), DASH (p< 0. 005), WORC (p< 0.001) and WST (p< 0.01). Within each group there was significant improvement in strength (p< 0.01) over time. The smaller tear group showed significantly greater strength. The ROM was improved within each group over time (p< 0.01), though no statistical difference was determined between groups. In comparing the sample based on WSIB status, functional outcomes were better in Non-WSIB patients (p< 0.01). Although no statistical difference in strength and ROM was noted.

Patients with both small and large tears showed improved functional outcome, strength and ROM over time, with the smaller tear group having better outcomes. WSIB patients had lower functional outcomes despite strength and ROM showing no difference between the two groups.