A population study in the Province of Ontario of the complications after conversion of hip or knee arthrodesis to total joint replacement

Objective — To evaluate the complication rates after conversion of hip and knee fusions to total joint replacements in the Province of Ontario.

Design — A retrospective cohort study.

Patients — Those who had undergone an elective conversion of a hip or knee fusion to a total joint replacement during fiscal year 1993 through 1996, as captured in the Canadian Institute for Health Information and Ontario Health Insurance Plan databases.

Outcome Measures — In hospital complications and length of initial hospital stay, revision, infection, amputation and repeat fusion rates within 4 years.

Results — Conversion of hip and knee fusion to total joint arthroplasty was generally performed by high-volume surgeons in high-volume hospital settings. Forty hip and 18 knee replacements involved conversion of a previous fusion. Conversion of a hip fusion was associated with a 10% infection rate, a 10% revision rate and a 5% resection arthroplasty rate due to infection within 4 years of the conversion. Conversion of a knee fusion was associated with an 11% infection rate, and a more than 5% revision rate at 4 years. Over 16% of patients who underwent conversion of a knee fusion required removal of the components (for various reasons) within the first 4 years.

Conclusions — There is a high rate of complications after conversion of a hip or knee fusion to a total joint arthroplasty. These issues must be carefully considered and discussed with the patient before any conversion procedure.