The zona conoidea comprises the area of the lateral
trochlear ridge of the humerus. The purpose of this study is to reintroduce
this term ‘zona conoidea’ to the discussion of the human elbow and
to investigate its significance in the development of osteoarthritis
of the elbow. The upper extremities of 12 cadavers were prepared. With the
forearm in neutral, pronation and supination, the distance between
the bevel of the radial head and zona conoidea was inspected. A
total of 12 healthy volunteers had a CT scan. The distance between
the zona conoidea and the bevelled rim of the radial head was measured
in these positions. In the anatomical specimens, early osteo-arthritic changes were
identified in the posteromedial bevelled rim of the radial head,
and the corresponding zona conoidea in supination. Measurement in
the CT study showed that in full supination, the distance between
the bevel of the radial head and the zona conoidea was at a minimum. This study suggests that the significant contact between the
bevel of the radial head and the zona conoidea in supination is
associated with the initiation of osteoarthritis of the elbow in
this area.
We report the effectiveness of revision of total
elbow replacement by re-cementing. Between 1982 and 2004, 53 elbows
in 52 patients were treated with re-cementing of a total elbow replacement
into part or all of the existing cement mantle or into the debrided
host-bone interface, without the use of structural bone augmentation
or a custom prosthesis. The original implant revision was still
This study reports our experience with total elbow replacement for fused elbows. Between 1982 and 2004, 13 patients with spontaneously ankylosed elbows were treated with a linked semi-constrained non-custom total elbow implant. The mean age at operation was 54 years (24 to 80). The stiffness was a result of trauma in ten elbows, juvenile rheumatoid arthritis in one, and rheumatoid arthritis in two. The patients were followed for a mean of 12 years (2 to 26) and were evaluated clinically using the Mayo Elbow Performance Score, as well as radiologically. A mean arc from 37° of extension to 118° of flexion was achieved. Outcomes were good or excellent for seven elbows at final review. Ten patients felt better or much better after total elbow replacement. However, there was a high complication rate and re-operation was required in over half of patients. Two developed peri-operative soft-tissue breakdown requiring debridement. A muscle flap with skin grafting was used for soft-tissue cover in one. Revision was undertaken in one elbow following fracture of the ulnar component. Three patients developed a deep infection. Three elbows were manipulated under anaesthesia for post-operative stiffness. Prophylactic measures for heterotopic ossification were unsuccessful. Total elbow replacement for the ankylosed elbow should be performed with caution. However, the outcome can be reliable in the long term and have a markedly positive impact on patient function and satisfaction. The high potential for complications must be considered. We consider total elbow replacement to be an acceptable procedure in selected patients with reasonable expectations.