Time Required for Planned and Unplanned Episodes of Care in Septic and Aseptic Hip and Knee Revision Surgery

Background: Surgical reimbursement rates are established by the Centers for Medicare and Medicaid Services (CMS). Studies have indicated that revision hip (rTHA) and knee (rTKA) arthroplasties require significantly more work effort, but are reimbursed less than primary procedures. This study quantified planned and unplanned work performed for revision surgeries by the surgeon and/or the surgeon’s team during the episode of care “reimbursement window.” Quantification of time was performed separately for aseptic and septic (two-stage) revisions and compared to allowed reimbursement amounts. Methods: All unilateral rTHA and rTKA procedures performed over a 10-year period by a single surgeon at a single institution were retrospectively reviewed. Time dedicated to planned work was calculated over each episode of care, from surgery scheduling to 90 days postoperatively. Impromptu patient inquiries and treatments after discharge, but within the episode of care, involving the surgeon/surgeon team constituted unplanned work. Planned and unplanned work minutes were summed and divided by the number of patients reviewed to obtain average minutes of work per patient. Results: Calculations demonstrated average per patient work for aseptic rTKA exceeded the reimbursable amount by 31 minutes. Calculated average minutes of work per patient required for aseptic rTHA fell within the number of minutes approved for reimbursement. Average per patient work for septic rTKA and rTHA exceeded the reimbursable amounts by 331 and 166 minutes, respectively, equating to 2.8 to 5.5 hours of uncompensated time. Conclusion: Revision hip and knee procedures are substantially more complex than primary procedures, with many surgeons referring patients to out-of-network care. Financially dis-incentivizing surgeons to care for these patients reduces patient access to care when high quality care is needed the most, especially infection cases susceptible to high sepsis and mortality rates. Study findings will be applied to advocacy efforts for appropriate legislative reform.

Intraoperative Fractures of the Tibia and Femur in Knee Revision Surgery

Intra-operative fractures in knee revision surgery are relatively rare and have not been well studied. They may occur during joint exposition, removal of the prosthesis or cement, or implantation of trial or original components. The fractures affect both the metaphyseal area and diaphysis of the tibia and femur. Tibial fractures are slightly more common than femur fractures. On the femur, the medial condyle is most frequently affected, followed by the femur diaphysis. The use of non-cemented stems is associated with a greater risk of intra-operative diaphyseal fractures than that of cemented stems. Overall, women and patients with an osteopenic bone structure have a higher risk of fractures. It is common that fractures are diagnosed post-operatively. In these cases, conservative therapy may be successful, depending on the stability of the prosthesis and bones. The most common surgical fixation options are cerclages and screws, followed by stem extensions for bridging the fracture. Plate fixation or use of strut grafts are also sensible therapy options. Overall, intraoperative fractures have a high healing potential with stable and good joint function. The revision rate is still 15%, which is most often caused by peri-prosthetic infection.

Elevated ESR and CRP Prior to Second-Stage Reimplantation Knee Revision Surgery for Periprosthetic Joint Infection Are Associated with Increased Reinfection Rates

Purpose Although two-stage revision surgery is considered as the most effective treatment for managing chronic periprosthetic joint infection (PJI), there is no current consensus on the predictors of optimal timing to second-stage reimplantation. This study aimed to compare clinical outcomes between patients with elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) prior to second-stage reimplantation and those with normalized ESR and CRP prior to second-stage reimplantation. Methods We retrospectively reviewed 198 patients treated with two-stage revision total knee arthroplasty for chronic PJI. Cohorts included patients with: (1) normal level of serum ESR and CRP (n = 96) and (2) elevated level of serum ESR and CRP prior to second-stage reimplantation (n = 102). Outcomes including reinfection rates and readmission rates were compared between both cohorts. Result At a mean follow-up of 4.4 years (2.8–6.5 years), the elevated ESR and CRP cohort demonstrated significantly higher reinfection rates compared with patients with normalized ESR and CRP prior to second-stage reimplantation (33.3% vs. 14.5%, p < 0.01). Patients with both elevated ESR and CRP demonstrated significantly higher reinfection rates, when compared with patients with elevated ESR and normalized CRP (33.3% vs. 27.6%, p = 0.02) as well as normalized ESR and elevated CRP (33.3% vs. 26.3%, p < 0.01). Conclusion This study demonstrates that elevated serum ESR and/or CRP levels prior to reimplantation in two-stage knee revision surgery for chronic PJI are associated with increased reinfection rate after surgery. Elevation of both ESR and CRP were associated with a higher risk of reinfection compared with elevation of either ESR or CRP, suggesting the potential benefits of normalizing ESR and CRP prior to reimplantation in treatment of chronic PJI.

Adherence to a reliable PJI diagnostic protocol minimizes unsuspected positive cultures rate

Background The aim of the present study was to evaluate the incidence of unsuspected PJI when prosthetic revisions are thoroughly evaluated by PJI dedicated orthopedic surgeon before surgery. The hypothesis is that the incidence of unsuspected PJI is reduced by applying this protocol. Methods This is a historical cohort study carried out in one university hospital. The prosthetic revision assessment was carried out in January 2019. From that date on, all patients that were programmed for hip or knee revision (either by an orthopedic surgeon specialized or not in septic revisions) were scheduled for a preoperative visit with the same orthopedic surgeon specialized in septic revisions. The diagnostic algorithm applied was based on the Pro-Implant Foundation diagnostic criteria. Prior to the revision assessment, the indication for joint aspiration was done at the surgeons’ discretion (non-specialized in septic revisions) and the preoperative identification of PJI was also done by a hip or knee surgeon (not specialized in septic surgery). Results Based on the PIF criteria, there were 15 infections among the revisions in group 1 and 18 PJI in group 2 (p > 0.05). The most interesting finding was that there were 7 patients with unsuspected positive cultures in group 1. That represents 11% of all revisions. No patient in group 2 was found with unsuspected positive cultures (p < 0.001). Conclusion A thorough PJI diagnostic algorithm should be implemented before prosthetic revision to avoid unsuspected positive cultures.

Revision of total knee replacement (TKR) secondary to raised cobalt levels: should this be considered in the painful TKR patient?

A 63-year-old woman was referred to the specialised knee revision clinic with ongoing knee pain after total knee replacement. She incidentally had cobalt and chromium levels measured. These were seen to be elevated. Comprehensive assessment and investigation did not identify any other source of cobalt or chromium. Aseptic loosening of the knee was diagnosed, and the knee was revised. At the time of surgery, the tissue was seen to be darkened consistent with metallosis. Multiple samples excluded infection on extended cultures. Aspirated fluid showed that periprosthetic fluid had elevated cobalt levels. The knee was successfully revised with good symptomatic outcome and significantly, over the course of several months post-revision, the cobalt and chromium levels returned to normal.