Arthrodesis should be strongly considered after failed two-stage reimplantation TKA

Abstract

Background: A two-stage reimplantation procedure is a well-accepted procedure for management of first-time infected total knee arthroplasty (TKA). However, there is a lack of consensus on the treatment of subsequent reinfections.

Questions/purposes: The purpose of this study was to perform a decision analysis to determine the treatment method likely to yield the highest quality of life for a patient after a failed two-stage reimplantation.

Methods: We performed a systematic review to estimate the expected success rates of a two-stage reimplantation procedure, chronic suppression, arthrodesis, and amputation for treatment of infected TKA. To determine utility values of the various possible health states that could arise after two-stage revision, we used previously published values and methods to determine the utility and disutility tolls for each treatment option and performed a decision tree analysis using the TreeAgePro 2012 software suite (Williamstown, MA, USA). These values were subsequently varied to perform sensitivity analyses, determining thresholds at which different treatment options prevailed.

Results: Overall, the composite success rate for two-stage reimplantation was 79.1% (range, 33.3%-100%). The utility (successful outcome) and disutility toll (cost for treatment) for two-stage reimplantation were determined to be 0.473 and 0.20, respectively; the toll for undergoing chronic suppression was set at 0.05; the utility for arthrodesis was 0.740 and for amputation 0.423. We set the utilities for subsequent two-stage revision and other surgical procedures by subtracting the disutility toll from the utility each time another procedure was performed. The two-way sensitivity analysis varied the utility status after an additional two-stage reimplantation (0.47-0.99) and chance of a successful two-stage reimplantation (45%-95%). The model was then extended to a three-way sensitivity analysis twice: once by setting the variable arthrodesis utility at a value of 0.47 and once more by setting utility of two-stage reimplantation at 0.05 over the same range of values on both axes. Knee arthrodesis emerged as the treatment most likely to yield the highest expected utility (quality of life) after initially failing a two-stage revision. For a repeat two-stage revision to be favored, the utility of that second two-stage revision had to substantially exceed the published utility of primary TKA of 0.84 and the probability of achieving infection control had to exceed 90%.

Conclusions: Based on best available evidence, knee arthrodesis should be strongly considered as the treatment of choice for patients who have persistent infected TKA after a failed two-stage reimplantation procedure. We recognize that particular circumstances such as severe bone loss can preclude or limit the applicability of fusion as an option and that individual clinical circumstances must always dictate the best treatment, but where arthrodesis is practical, our model supports it as the best approach.

Fig. 1

Systematic review of the literature on the two-stage reimplantation procedure for management of infected TKA. The search strategy including search criteria and subsequent exclusions is depicted in this flow diagram.

Fig. 2

Systematic review of the literature on knee arthrodesis after failed TKA. The search strategy including search criteria and subsequent exclusions is depicted in this flow diagram.

Fig. 3

Systematic review of the literature on AKA after infected TKA. The search strategy including search criteria and subsequent exclusions is depicted in this flow diagram.

Fig. 4

Systematic review of the literature on chronic suppression in the setting of infected TKA. The search strategy including search criteria and subsequent exclusions is depicted in this flow diagram.

Fig. 5

Graphic representation of care decision-making in a simulated patient status after failed two-stage revision. The boxed values represent starting values and their assigned respective variable names. The blue square node is the decision node. The green circle node is the probability node, where literature values on the probability of future outcomes are computed. The red node is the terminal node, where infection is resolved. Texts above each line represent the status of the patient at that specific stage. The numbers and texts below each line represent the formula used to calculate the probability of entering that branch of the tree. The formula to the right of the terminal node calculates the utility gained from having traversed down that specific branch.

Fig. 6A–B

(A) Two-way sensitivity analysis. Color represents the preferred treatment choice for the patient to maximize utility. Fusion is the dominant strategy, except in regions where success rate of two-stage reimplantation is expected to be >90% and revision utility >0.95. (B) Three-way sensitivity analysis. Color represents the preferred treatment choice for the patient to maximize utility. Fusion is the dominant strategy unless revision utility is at least greater than 0.80. Above revision utility of 0.80, >65% chance of revision success rate will favor two-stage reimplantation, whereas a >0.90 revision utility but <65% chance of revision success rate will favor chronic suppression as the treatment choice for maximizing utility. Rv = revision; 2SR (2) = two-stage reimplantation.