Prosthetic replacement of the arthritic knee after patellectomy.

The results of total knee replacement with a semiconstrained prosthesis after patellectomy are poor because the stabilizing effect of the patella is lost. A series of bicompartmental unicompartmental knee replacements (five patients) carried out for this condition was compared with a series of Insall-Burstein posterior stabilized knee prostheses (six patients). If both cruciate ligaments are present the results are not notably different, but those with an Insall-Burstein prosthesis generally fared better at stair-climbing using the replaced side as the lead leg. Since the Insall-Burstein knee is technically easier to implant there seems little to recommend the bicompartmental unicompartmental prosthesis in this condition.