The aim of this study was to evaluate the kinematics of the elbow following increasing length of the radius with implantation of radial head arthroplasties (RHAs) using dynamic radiostereometry (dRSA). Eight human donor arms were examined by dRSA during motor-controlled flexion and extension of the elbow with the forearm in an unloaded neutral position, and in pronation and supination with and without a 10 N valgus or varus load, respectively. The elbows were examined before and after RHA with stem lengths of anatomical size, + 2 mm, and + 4 mm. The ligaments were maintained intact by using a step-cut lateral humeral epicondylar osteotomy, allowing the RHAs to be repeatedly exchanged. Bone models were obtained from CT scans, and specialized software was used to match these models with the dRSA recordings. The flexion kinematics of the elbow were described using anatomical coordinate systems to define translations and rotations with six degrees of freedom.Aims
Methods
Conservative treatment of moderately displaced proximal humeral head fractures yields good clinical results, but secondary fragment displacement may occur. Identification of those fractures at risk of displacement may influence initial decision-making. A total of 163 shoulders in 162 patients with conservatively treated isolated proximal humeral fractures were included. The fractures occurred between January 2015 and May 2018. The mean age of the patients was 69 years (26 to 100) and the mean follow-up was 144 days (42 to 779). The fractures were classified according to Neer. Scores for osteoporosis (Tingart, Deltoid Tuberosity Index (DTI)) and osteoarthritis (OA) of the glenohumeral joint were assessed. Translation of the head on follow-up radiographs of more than 10 mm was defined as displacement. Eccentric head index (EHI) describes the offset of the humeral head centre in relation to the diaphyseal axis. The ratio was estimated on anteroposterior (AP) and Neer views. Medial hinge was considered intact if the medial cortex proximal and distal to the fracture was in line on AP view.Aims
Methods
Osteoarthritis results in changes in the dimensions
of the glenoid. This study aimed to assess the size and radius of curvature
of arthritic glenoids. A total of 145 CT scans were analysed, performed
as part of routine pre-operative assessment before total shoulder
replacement in 91 women and 54 men. Only patients with primary osteoarthritis and
a concentric glenoid were included in the study. The CT scans underwent
three-dimensional (3D) reconstruction and were analysed using dedicated
computer software. The measurements consisted of maximum superoinferior height,
anteroposterior width and a best-fit sphere radius of curvature
of the glenoid. The mean height was 40.2 mm ( With current shoulder replacement systems using a unique backside
radius of curvature for the glenoid component, there is a risk of
undertaking excessive reaming to adapt the bone to the component
resulting in sacrifice of subchondral bone or under-reaming and
instability of the component due to a ’rocking horse‘ phenomenon. Cite this article:
