Recurrence of ectopic ossification after excision in Charnley Low Friction Arthroplasty

In 23 hips with a Charnley Low Friction Arthroplasty (L.F.A.), revised for mechanical reasons, a planimeter was used to study areas of ectopic ossification and their recurrence after excision. In two cases some bone resorption had taken place. In the remaining 21 hips the average area of recurrence was greater than the average area excised. There was no correlation between the time elapsed and the extent of ossification; once established, the ossification did not seem to progress. Revision of L.F.A. for excision of ectopic bone is not indicated.