Prior unilateral total hip arthroplasty does not influence the outcome of ipsilateral total knee arthroplasty.

PURPOSE: To assess the influence of a prior well-functioning unilateral primary total hip arthroplasty (THA) on the functional outcome of a subsequent ipsilateral primary total knee arthroplasty (TKA). METHODS: A retrospective case-control study of 92 patients older than 60 years underwent unilateral primary TKA after a prior ipsilateral THA (THA-TKA group) and 92 matched patients underwent only TKA (TKA group). Clinical assessments were performed using the Knee Society Scores (KSS) and Harris Hip Score (HSS), quality of life by the Reduced Western Ontario and MacMaster Universities (WOMAC) and Short-Form 12 (SF-12) questionnaires. Radiological evaluation was also performed. RESULTS: Median follow-up after TKA was 7.2 (range 5-9) years. There were no significant differences between groups in baseline data at the TKA time. The mean gains in KSS were similar in both groups. At the last follow-up, there were no significant differences in WOMAC-pain or SF12-physical scores, but the WOMAC-function (p = 0.003) and SF12-mental (p = 0.018) scores were significantly better in the isolated TKA group. At the last follow-up, there were no significant differences in the radiological knee alignment or component positions. For aseptic reasons, the TKA survival at 8 years in the TKA group was 95.8 (95% CI 87.8-100%), and 96.6% (95% CI 91.8-100%) in the THA-TKA group (ns). CONCLUSION: A well-functioning unilateral THA does not influence on the functional outcome of a subsequent ipsilateral TKA. This finding can help clinicians when counseling patients with hip and knee osteoarthritis. LEVEL OF EVIDENCE: III.

Negative impact of prior debridement on functional outcome of subsequent two-stage revision for early knee periprosthetic infection.

PURPOSE: To compare the functional outcome of two-stage revision (2SR) in patients without a prior debridement, antibiotics and implant retention with those patients who underwent 2SR after a failed debridement, antibiotics and implant retention for early periprosthetic joint infection following total knee arthroplasty (TKA). Negative impact of prior failed debridement, antibiotics and implant retention on the functional outcome of subsequent 2SR was hypothesized. METHODS: Case-control study of 49 patients initially treated with 2SR (group A) and 43 treated with 2SR after a prior failed debridement, antibiotics and implant retention (group B). Functional outcome was assessed by the Knee Society Scores (KSS) and Western Ontario and McMaster Universities (WOMAC) questionnaire. Range of motion (ROM) of the knee was also measured. RESULTS: The median follow-up was 4.1 (range 3-7) years. At final follow-up, KSS-knee (p = 0.001), KSS-function (p = 0.002), WOMAC-function (p = 0.022) and ROM (p = 0.002) were significantly better in the group A as compared to the group B. There was no significant difference between groups in the WOMAC-pain score (p = 0.597). In multivariate analysis, BMI < 30 (OR 3.1, 95% CI 1.7-4.9, p = 0.026), non- Staphylococcus causative microorganism (OR 2.7, 95% CI 1.6-5.9, p = 0.037), and 2SR procedure (OR 2.4, 95% CI 1.7-5.2, p = 0.018) were significant predictors of successful functional outcome. CONCLUSIONS: A prior debridement, antibiotics and implant retention has been shown to have a negative impact on the functional outcome of a subsequent 2SR. These findings suggest that treatment with debridement, antibiotics and implant retention for early periprosthetic infection should only be used in selected patients, and the first option in those patients with Staphylococcus organisms should be 2SR. LEVEL OF EVIDENCE: IV.