We reviewed the initial post-operative radiographs of the Trident acetabulum and identified a problem with seating of the metal-backed ceramic liner. We identified 117 hips in 113 patients who had undergone primary total hip replacement using the Trident shell with a metal-backed alumina liner. Of these, 19 (16.4%) were noted to have incomplete seating of the liner, as judged by plain anteroposterior and lateral radiographs. One case of complete liner dissociation necessitating early revision was not included in the prevalence figures. One mis-seated liner was revised in the early post-operative period and two that were initially incompletely seated were found on follow-up radiographs to have become correctly seated. There may be technical issues with regard to the implanting of this prosthesis of which surgeons should be aware. However, there is the distinct possibility that the Trident shell deforms upon implantation, thereby preventing complete seating of the liner.

Background: The fluoroscopic detection of dorsal screw protrusion following volar locking plate fixation of distal radius fractures remains difficult. The carpal shoot through view has recently been reported to result in a 17% intraoperative screw exchange rate. The aim of the current study was to assess the sensitivity of the carpal shoot through view in comparison to conventional fluoroscopic views for detecting dorsal cortical and distal radio-ulnar joint screw penetration. Methods: A volar locking plate was applied to a saw bone model and fluoroscopic views taken with the distal screws inserted flush or protruding by two full screw threads. Images were then shown to 10 orthopaedic surgeons who were asked to identify excessively long screws. Results: The CST view demonstrated the greatest sensitivity for detection of dorsal screw penetration (78%). Its interobserver reliability was 0.66 (substantial agreement) and intra-observer reliability 0.86 (near perfect agreement). The dorsal skyline had a sensitivity of 51%; the elevated lateral view had a sensitivity of only 16%. Conclusions: The current study confirms that the elevated lateral view cannot be relied upon alone for the detection of dorsal screw penetration. The CST view is a valid technique demonstrating the greatest sensitivity in comparison to established intra-operative views.

Using the hand and carpus to minimise the contrast in X-ray penetration, the dorsal cortex of the distal radius may be imaged intra-operatively and dorsal compartment screw penetration detected in cases with significant multifragmentation when screw measurement is difficult. This view potentially reduces the risk of post-operative pain and extensor tendon injury and also provides excellent visualisation of the DRUJ.