Abstract
This novel modification of the posterior approach allows a low hazard exposure and easier surgery to the radial head.
Methods and Materials: The most commonly used approaches are from the lateral aspect. The limitations of this approach in particular for radial head replacement is that it is a tight exposure, there is a risk of damage to the posterior interosseous nerve and there is always a difficulty in dislocation due to the presence of the interosseous membrane. The posterolateral approach to the proximal radius and ulna was described by Boyd, Gordon and Thompson. This approach avoids damage to the posterior interosseous nerve but the annular ligament requires incision and repair.
Approach: Position the forearm in pronation aligning the ulnar styloid with lateral epicondyle of the humerus. A tencentimetre long incision is then made on the lateral border of the ulna exposing deep fascia. Following this a 1cm flap of fascia is left on the ulna and anconeus is lifted off the bone. This exposes underlying radial head, annular ligament and interosseous membrane. After identifying the ulnar insertion of annular ligament a 0.5 cm bone is osteotomised with annular ligament attached from the supinator tuberosity. The radial head osteotomy is performed with the radial head in pronation to align it with shaft of radius using specially designed jig. Osteotomy of the radial head has to be at right angles to the axis of the forearm. This is a line between centre of the radial neck to the ulnar styloid process. Radial head can now be subluxed out of the wound and preparing for a replacement. The trial prosthetic radial head is then inserted and reduced. The bone fragment with annular ligament attachment is then reduced back into the original slot. This allows one to judge the size of prosthetic radial head if ligament is too tight a small diameter implant is required. The bone fragment is reattached using especially devised washer with, wire holes and a 2mm AO screw.
Results: This approach is easier, safer and reproducible. When compared to lateral approach it provides an easier access and excellent stability in radial head replacement. We recommend this approach for radial head replacements and difficult trauma cases.
The abstracts were prepared by David Stanley. Correspondence should be addressed to him c/o British Orthopaedic Association, Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London WC2A 3PN.
