Fungal prosthetic joint infection after total knee arthroplasty
A 62 year old hypertensive non diabetic female presented with pain, swelling in the left knee and difficulty in walking in the left knee for the last 6 weeks. A TKA of the left knee was done 2 years ago. She had an uneventful period after the TKA.\nOn examination, a 15 cm vertical midline surgical scar healed by primary intention of the initial TKA was present on anterior aspect of knee. The local temperature was raised. The range of motion was terminally restricted in flexion and was associated with pain. No deformity was noted, however, mediolatera instability was present. Patient was neurologically intact and distal pulsations were well felt.\nRadiologically, there was osteolysis over the anterior femoral cortex, posterior femoral condyles and under the tibial base plate []. Complete hematological study and urine microscopy revealed no significant abnormality besides elevated erythrocyte sedimentation rate (ESR) (75 mm at 1 hour) and C-reactive protein (CRP) (84 mg/l).\nKnee joint aspiration was carried out under sterile conditions. The fluid obtained was sent for analysis. Characteristics of the aspirate were 5 ml fluid, cloudy with low viscosity, white blood cell count was 15,000/cubic mm, with 68% polymorphonuclear leucocytes. Gram staining was negative, but 10% KOH mount, done to rule out fungal infection as a standard hospital protocol, was positive suggesting a fungal infection.\nA decision to perform 1st stage of revision TKA was taken after consultation with the patient and her family. In consultation with infectious disease specialist, it was decided to culture and identify the organism on intraoperative samples. The previous vertical incision was used to approach the joint. Per-operatively there was turbid synovial fluid, granulation tissue, implant loosening and adherent cement Synovial fluid and tissue was sent for culture and sensitivity studies.\nImplant removal, debridement and antibiotic (vancomycin) plus antifungal (amphotericin B) impregnated cement spacer insertion was done []. Post-operative period was uneventful []. Medical therapy included intravenous fluconazole 400 mg OD for 6 weeks followed by oral fluconazole 400 mg BD for 12 weeks. Bacterial culture was negative. Fungal culture was positive for Candida tropicalis. Sabouraud dextrose agar and the rapid API 20 microtube system were used for identification of species. Antifungal sensitivity was performed on the isolate.\nPatient was followed up at weekly intervals and after 20 weeks, the ESR (23 mm at 1 hour) and CRP (6.3 mg/l) were within normal limits. Repeat aspiration was sterile. During the 2nd stage of revision, TKA quadriceps snip technique was used. Spacer was removed; the defect was non contained involving cortical and metaphyseal bone. TC3 Depuy system and fluted stems were implanted (Depuy, India). Posterior femoral augmentation and reconstruction with allograft was done. Femoral head allograft was used as bone graft to fill up the defect. There was no maltracking of patella []. Tissue was sent for microbial analysis, which turned negative. Postoperative period was uneventful and patient was discharged on oral fluconazole 400 mg BD for 10 weeks.\nThe surgical wound healed adequately and after physiotherapy, a painless range of motion of 10-90° with a stable knee was obtained. We did not use any scoring system pre or postoperatively. Patient maintained status quo until last followup 24 months after 2nd stage of revision surgery [].