Marginal contribution of UKS- versus TKA in varus arthritis of the knee.

BACKGROUND: In recent years, decisions regarding the treatment of individual patients have increasingly been affected by economic considerations. The G-DRG system reimburses sledge endoprosthetic implantations at a much lower rate than surface replacements and at significantly different cost weights (CW). Therefore, when only G-DRG payments are considered, TKA produces higher gains. Taking only these revenues alone into consideration, however, does not provide the basis of an economically sound decision-making process. The target of this research was to present a comparison between variable costs of the two procedures. METHODS: The mean cost and performance data of 28 Endo-Modell (Link company) sledge implantations (UKS) and of 85 NexGen CR surface replacement total knee arthroplasties (TKA; Zimmer company) were compared in 2007. RESULTS: From the perspective of the hospital, UKS treatment is of greater economic advantage when the medical indication is given. In preferring UKS marginal contribution can be improved, and although the relative weighting is comparatively low, the costs are significantly lower than in a comparative analysis of TKA. Based on the length of stay required for each procedure the average daily CW for UKS can be calculated as 0.1728, while being 0.1955 for TKA. The earlier release of the first patient results in another patient being admitted 1.5 days earlier and thus an increase in case mix. Meanwhile, the case-mix index and the costs of care per case decrease ceteris paribus. CONCLUSION: Assuming the correct medical indication, the hospital seeking to maximize its marginal contribution would be wise to select sledge endoprosthesis implantation. Considering the economic perspective of gains and costs, the assumption that TKA is advantageous could not be confirmed in the present study.

Comparative Analysis of Direct Hospital Care Costs between Aseptic and Two-Stage Septic Knee Revision.

BACKGROUND: The most common intermediate and long-term complications of total knee arthroplasty (TKA) include aseptic and septic failure of prosthetic joints. These complications cause suffering, and their management is expensive. In the future the number of revision TKA will increase, which involves a greater financial burden. Little concrete data about direct costs for aseptic and two-stage septic knee revisions with an in depth-analysis of septic explantation and implantation is available. QUESTIONS/PURPOSES: A retrospective consecutive analysis of the major partial costs involved in revision TKA for aseptic and septic failure was undertaken to compare 1) demographic and clinical characteristics, and 2) variable direct costs (from a hospital department's perspective) between patients who underwent single-stage aseptic and two-stage septic revision of TKA in a hospital providing maximum care. We separately analyze the explantation and implantation procedures in septic revision cases and identify the major cost drivers of knee revision operations. METHODS: A total of 106 consecutive patients (71 aseptic and 35 septic) was included. All direct costs of diagnosis, surgery, and treatment from the hospital department's perspective were calculated as real purchase prices. Personnel involvement was calculated in units of minutes. RESULTS: Aseptic versus septic revisions differed significantly in terms of length of hospital stay (15.2 vs. 39.9 days), number of reported secondary diagnoses (6.3 vs. 9.8) and incision-suture time (108.3 min vs. 193.2 min). The management of septic revision TKA was significantly more expensive than that of aseptic failure ($12,223.79 vs. $6,749.43) (p <.001). On the level of the separate hospitalizations the mean direct costs of explantation stage ($4,540.46) were lower than aseptic revision TKA ($6,749.43) which were again lower than those of the septic implantation stage ($7,683.33). All mean costs of stays were not comparable as they differ significantly (p <.001). Major cost drivers were the cost of the implant and general staff. The septic implantation part was on average $3,142.87 more expensive than septic explantations (p <.001). CONCLUSIONS: Our study for the first time provides a detailed analysis of the major direct case costs of aseptic and septic revision TKA from the hospital-department's perspective which is the basis for long-term orientated decision making. In the future, our cost analysis has to be interpreted in relation to reimbursement estimates. This is important to check whether revision TKA lead to a financial loss for the operating department.