Plating displaced proximal humeral fractures is associated with a high rate of screw perforation. Dynamization of the proximal screws might prevent these complications. The aim of this study was to develop and evaluate a new gliding screw concept for plating proximal humeral fractures biomechanically. Eight pairs of three-part humeral fractures were randomly assigned for pairwise instrumentation using either a prototype gliding plate or a standard PHILOS plate, and four pairs were fixed using the gliding plate with bone cement augmentation of its proximal screws. The specimens were cyclically tested under progressively increasing loading until perforation of a screw. Telescoping of a screw, varus tilting and screw migration were recorded using optical motion tracking.Aims
Methods
Scapulothoracic fusion (STF) for painful winging
of the scapula in neuromuscular disorders can provide effective pain
relief and functional improvement, but there is little information
comparing outcomes between patients with dystrophic and non-dystrophic
conditions. We performed a retrospective review of 42 STFs in 34
patients with dystrophic and non-dystrophic conditions using a multifilament
trans-scapular, subcostal cable technique supported by a dorsal
one-third semi-tubular plate. There were 16 males and 18 females
with a mean age of 30 years (15 to 75) and a mean follow-up of 5.0
years (2.0 to 10.6). The mean Oxford shoulder score improved from
20 (4 to 39) to 31 (4 to 48). Patients with non-dystrophic conditions
had lower overall functional scores but achieved greater improvements
following STF. The mean active forward elevation increased from
59° (20° to 90°) to 97° (30° to 150°), and abduction from 51° (10°
to 90°) to 83° (30° to 130°) with a greater range of movement achieved
in the dystrophic group. Revision fusion for nonunion was undertaken
in five patients at a mean time of 17 months (7 to 31) and two required
revision for fracture. There were three pneumothoraces, two rib
fractures, three pleural effusions and six nonunions. The main risk
factors for nonunion were smoking, age and previous shoulder girdle surgery. STF is a salvage procedure that can provide good patient satisfaction
in 82% of patients with both dystrophic and non-dystrophic pathologies,
but there was a relatively high failure rate (26%) when poor outcomes
were analysed. Overall function was better in patients with dystrophic
conditions which correlated with better range of movement; however,
patients with non-dystrophic conditions achieved greater functional
improvement.
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 aim of this study was to define the microcirculation of the normal rotator cuff during arthroscopic surgery and investigate whether it is altered in diseased cuff tissue. Blood flow was measured intra-operatively by laser Doppler flowmetry. We investigated six different zones of each rotator cuff during the arthroscopic examination of 56 consecutive patients undergoing investigation for impingement, cuff tears or instability; there were 336 measurements overall. The mean laser Doppler flowmetry flux was significantly higher at the edges of the tear in torn cuffs (43.1, 95% confidence interval (CI) 37.8 to 48.4) compared with normal cuffs (32.8, 95% CI 27.4 to 38.1; p = 0.0089). It was significantly lower across all anatomical locations in cuffs with impingement (25.4, 95% CI 22.4 to 28.5) compared with normal cuffs (p = 0.0196), and significantly lower in cuffs with impingement compared with torn cuffs (p <
0.0001). Laser Doppler flowmetry analysis of the rotator cuff blood supply indicated a significant difference between the vascularity of the normal and the pathological rotator cuff. We were unable to demonstrate a functional hypoperfusion area or so-called ‘critical zone’ in the normal cuff. The measured flux decreases with advancing impingement, but there is a substantial increase at the edges of rotator cuff tears. This might reflect an attempt at repair.