Surgery Prior to Subspecialty Referral for Periprosthetic Knee Infection Reduces the Likelihood of Eradication

Introduction: Failure to eradicate a periprosthetic joint infection (PJI) often leads to patient referral to a tertiary care institution (TCI). We sought to determine whether surgery for PJI prior to referral to a TCI for definitive management of PJI influences infection free implant survival.

Methods: We reviewed 163 TKAs surgically treated for PJI between 2004 and 2014. Eighty-eight (54%) TKAs had no surgical treatment prior to referral to our institution for management of PJI, and 75 (46%) TKAs had surgery prior to referral. Follow-up averaged 2.4±1.2 years for patients with surgery prior to referral and 2.8±1.3 years for patients with no prior surgery (p = 0.065). Infection free survival was defined as prosthesis retention without further surgical intervention in the absence of antibiotic suppression. Relative and absolute risk reductions with 95% confidence intervals, and Kaplan-Meier survival curve with Cox proportional hazard model adjusting for significant covariates were used to evaluate survival.

Results: The cumulative survival rate of TKAs with no surgery prior to referral at 2 years was 94% (95%CI:87-98%) compared to 80% (95%CI:69-87%) among TKAs with surgery prior to referral (p=0.006). The hazard ratio was 3.63 (95%CI:1.31-10.08, p=0.013) and a 14% increase in absolute risk for patients with prior surgery, compared to patients with no prior surgery. A causative microorganism was identified in 52 (69%) of TKAs with prior surgery, and in 77 (88%) of TKAs with no surgery prior to referral (p=0.006). Staphylococcal species were identified in 46 (61%) of TKAs with prior surgery versus 59 (67%) of TKAs that did not (p=0.064).

Conclusion: Surgical treatment of a PJI prior to referral for subspecialty surgical management increases the risk of failure of subsequent surgical management. As in orthopaedic oncology, surgical treatment of PJI prior to referral to a TCI with specialized expertise in PJI compromises infection free survival.