Metal-on-metal bearings for total hip replacement (THR) are becoming increasingly popular. Improved wear characteristics mean that these articulations are being inserted into younger patients in the form of THR and resurfacing procedures. This has led to concerns regarding potential carcinogenicity because of the increased exposure to metal ions that the procedure brings.

We have studied the serum cobalt and chromium concentrations in patients who had primary, well-fixed Ring metal-on-metal THRs for more than 30 years. The levels of cobalt and chromium were elevated by five and three times, respectively compared with those in our reference groups. Metal-on-metal articulations appear to be the source of metal ions throughout the life of the prosthesis. In three patients who had undergone revision of a previous metal-on-metal THR to a metal-on-polyethylene replacement the levels of metal ions were within the normal range. The elevations of cobalt and chromium ions seen in our study were comparable with those in patients with modern metal-on-metal THRs.

Immunosuppression following intra-articular injections of steroid into the hip may interfere with asepsis in a subsequent total hip arthroplasty (THA). We have undertaken a retrospective, matched, cohort study of infective complications after THA, in 40 patients who had received such an injection and 40 who had not.

In the injection group there were five revisions, four of which were for deep infection. There were none in the matched group. The overall rate of revision in our database of 979 primary THAs was 1.02%. Six additional patients who had received injections underwent investigation for infection because of persistent problems in the hip as compared with one in the control group.

Traumatic atlanto-axial subluxation is a rare injury which may not be revealed on routine radiographs, especially when there is muscle spasm. We report on seven patients with atlanto-axial subluxation as a result of neck injury; only two of them had significant head injuries. Three patients presented with a neurological deficit attributable to the injury, one immediate and two with delayed onset. Traumatic atlanto-axial instability, occurring in an otherwise healthy patient, has a potential for neurological disaster; early consideration of operative treatment is indicated.

Isolated traumatic dislocation of the radial head in children is not as rare as sometimes supposed. Attention to detail in radiographic interpretation is the key to diagnosis. Early closed reduction and immobilisation in an above-elbow plaster in 90 degrees of flexion and full supination for three to six weeks is recommended. Seven cases are presented, two of which were treated operatively and had unsatisfactory results. The applied anatomy, management and complications are discussed.