We report the histological findings in post-mortem specimens obtained ten days, 17 days and seven weeks after implantation of hydroxyapatite-coated femoral components of hip arthroplasties. There was early deposition of woven bone on the hydroxyapatite ceramic, identical to that deposited on surviving cancellous trabeculae. The space between these deposits became bridged from both sides by new trabeculae, and there was no evidence of an inflammatory reaction or of fibrous tissue formation. The use of an hydroxyapatite coating seems to allow early, sound, secondary fixation of implants.

Spinal osteochondrosis, previously known as Scheuermann's disease and spinal osteochondritis, is common and is probably becoming increasingly prevalent. Its incidence in patients whose primary complaint was of backache was shown to be twice as great as that in the general population. There was also a significantly higher incidence of lower lumbar spondylosis in patients with previous osteochondrosis compared with those without. Osteochondrosis is thereby shown to be an important aetiological factor in spondylosis.