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 k nee 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 f usion to a total joint replacement during fiscal year 1993 through 1996, as captured in the-Canadian Institute for Health Information and Ontario Heal th Insurance Plan databases. OUTCOME MEASURES: Inhospital complications and length of initial hospital s tay, 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 setting s. Forty hip and 18 knee replacements involved conversion of a previous fus ion. 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 wi thin 4 years of the conversion. Conversion of a knee fusion was associated with an 11% infection rate, and a more than 5% re vision rate at 4 years. O ver 16% of patients who underwent conversion of a knee fusion required remo val of the components (for various reasons) within the first 4 pears. CONCLUSIONS: There is a high rate of complications after conversion of a hi p or knee fusion to a total joint arthroplasty. These issues must be carefu lly considered and-discussed with the patient before any conversion procedu re.