Can Good Infection Control Be Obtained in One-stage Exchange of the Infected TKA to a Rotating Hinge Design? 10-year Results.

BACKGROUND: Prosthetic joint infection (PJI) occurs in 1% to 2% of total knee arthroplasties (TKAs). Although two-stage exchange is the preferred management method of patients with chronic PJI in TKA in North America, one-stage exchange is an alternative treatment method, but long-term studies of this approach have not been conducted.

QUESTIONS/PURPOSES: We reviewed our minimum 9-year results of 70 patients who underwent one-stage exchange arthroplasty with a rotating hinge design to determine: (1) What was the proportion of patients free of infection? (2) What was the patient rate of survival free of any reoperation? (3) What were the clinical outcomes as measured by Hospital for Special Surgery scores? (4) What proportion of patients developed radiographic evidence of loosening?

METHODS: All one-stage revision TKAs for infection between January 1 and December 31, 2002, with a minimum 9-year followup (mean, 10 years; range, 9-11 years), in which patients had been seen within the last 1 year, were included in this retrospective review. During that period, 11 patients with infected TKAs were treated with other approaches (including two-stage approaches in eight); the general indication for one-stage revision was the diagnosis of PJI with a known causative organism. Exclusion criteria were culture-negative preoperative aspiration, known allergy to local antibiotics or bone cement, or cases in which radical débridement was impossible as a result of the involvement of important anatomical structures. Eighty-one patients with PJI were seen during this period; 70 underwent one-stage exchange using our strict protocol and were reimplanted with a rotating hinge TKA. Eleven patients (15.7%) were lost to followup. Hospital for Special Surgery scores were recorded and all radiographs were evaluated for prosthetic loosening. Failure was defined as revision surgery for infection or any other cause.

RESULTS: Our 10-year infection-free survival was 93% (mean, 4.1; 95% confidence interval [CI], 89%-96%; p < 0.007); and the patient 10-year survival rate free of revision for other causes was 91% (mean, 5.2; 95% CI, 86%-95%; p < 0.002). Mean Hospital for Special Surgery knee score at last followup was 69.6 (± 22.5 SD; range, 22-100) and the mean improvement in Hospital for Special Surgery knee score from preoperative to most recent followup was 35 (± 24.2 SD; range, 13-99). Evidence of radiographic loosening was seen in 11 patients at last followup, whereby in six patients, there was need for revision surgery.

CONCLUSIONS: Our study results showed an overall infection control rate of 93% and good clinical results using our one-stage approach, which combines aggressive débridement of the collateral ligaments and posterior capsule with a rotating hinge implant. These results are comparable with two-stage techniques at a followup of 10 years; further research into one-stage exchange techniques for PJI in TKA appears warranted.

LEVEL OF EVIDENCE: Level IV, therapeutic study.