We hypothesised that a large acromial cover with
an upwardly tilted glenoid fossa would be associated with degenerative
rotator cuff tears (RCTs), and conversely, that a short acromion
with an inferiorly inclined glenoid would be associated with glenohumeral
osteoarthritis (OA). This hypothesis was tested using a new radiological parameter,
the critical shoulder angle (CSA), which combines the measurements
of inclination of the glenoid and the lateral extension of the acromion
(the acromion index). The CSA was measured on standardised radiographs of three groups:
1) a control group of 94 asymptomatic shoulders with normal rotator
cuffs and no OA; 2) a group of 102 shoulders with MRI-documented
full-thickness RCTs without OA; and 3) a group of 102 shoulders
with primary OA and no RCTs noted during total shoulder replacement.
The mean CSA was 33.1° (26.8° to 38.6°) in the control group, 38.0°
(29.5° to 43.5°) in the RCT group and 28.1° (18.6° to 35.8°) in
the OA group. Of patients with a CSA >
35°, 84% were in the RCT
group and of those with a CSA <
30°, 93% were in the OA group. We therefore concluded that primary glenohumeral OA is associated
with significantly smaller degenerative RCTs with significantly
larger CSAs than asymptomatic shoulders without these pathologies.
These findings suggest that individual quantitative anatomy may
imply biomechanics that are likely to induce specific types of degenerative
joint disorders. Cite this article:
Cadaveric models of the shoulder evaluate discrete motion segments
using the glenohumeral joint in isolation over a defined trajectory.
The aim of this study was to design, manufacture and validate a
robotic system to accurately create three-dimensional movement of
the upper body and capture it using high-speed motion cameras. In particular, we intended to use the robotic system to simulate
the normal throwing motion in an intact cadaver. The robotic system
consists of a lower frame (to move the torso) and an upper frame
(to move an arm) using seven actuators. The actuators accurately
reproduced planned trajectories. The marker setup used for motion
capture was able to determine the six degrees of freedom of all
involved joints during the planned motion of the end effector.Objectives
Methods
The results of proximal humeral replacement following trauma are substantially worse than for osteoarthritis or rheumatoid arthritis. The stable reattachment of the lesser and greater tuberosity fragments to the rotator cuff and the restoration of