A 63-year-old man presented at our institution with 3 years of right knee pain after primary total knee arthroplasty (TKA) performed in 2010 at another institution. The TKA had been complicated 2 years postoperatively by a periprosthetic joint infection (PJI) caused by methicillin-sensitive Staphylococcus aureus (MSSA) and treated with 6 revision surgeries (including placement of a static antibiotic spacer for 2-stage revision) and 6 courses of IV antibiotics. On presentation to HSS, the patient had draining sinuses at both ends of the incision for several months after his most recent revision. This drainage had been treated with serial vacuum dressings and then daily wet-to-dry dressings. The patient sought evaluation at the Stavros Niarchos Foundation Complex Joint Reconstruction Center for the recurrent PJI with a chronically draining sinus.
On examination, the patient had a moderate effusion, range of motion (ROM) of 15° to 90°, and good stability on varus and valgus stress. A 2-cm chronic wound at the distal aspect of the previous incision had active drainage, communication with the joint, and granulation tissue at its base. The incision was inflamed, and the surrounding skin was of poor quality due to maceration from chronic drainage and multiple surgeries. Right knee radiographs revealed a cemented stemmed femoral component and an all-polyethylene tibial component with significant femoral and tibial bone loss (Fig. 1). Laboratory results included a white blood cell (WBC) count of 5.9/nL, erythrocyte sedimentation rate of 37 mm/hr, and C-reactive protein of 6.4 mg/dL. Preoperative aspiration of synovial fluid showed a WBC count of 16,000 cells/mm3, and synovial fluid cultures grew MSSA, thus confirming a chronic infection of the multiply revised TKA.
Figure 1: Anteroposterior (A) and lateral (B) radiographs of the right knee of a patient who had undergone TKA and 6 revision procedures for PJI.
Our initial surgical procedure consisted of implant removal and thorough canal and bony surface debridement. Due to the poor quality of the soft-tissue envelope, the draining sinus tract was excised and a static antibiotic spacer with high doses of antibiotic cement was inserted. The spacer consisted of 2 fully cement-coated rush rods using 5 bags of Simplex® P cement (Stryker, Mahwah, NJ), with vancomycin 2 g and tobramycin 1.2 g added to each 40-g bag of cement (Fig. 2). The skin was closed primarily and treated with an incisional wound vacuum dressing postoperatively. The postoperative course was complicated by prolonged wound healing and a deep vein thrombosis at 2 weeks postoperatively, which was treated with rivaroxaban. The patient also received IV cefazolin for 6 weeks from the infectious disease team. Three weeks after completion of antibiotic therapy, aspiration of the knee revealed no bacterial growth or indication of infection.
Figure 2: Anteroposterior (A) and lateral (B) radiographs of the right knee after explantation and insertion of a static antibiotic cement spacer.
At 3 months after explantation, the patient underwent reimplantation TKA using a distal femoral replacement with tibial metaphyseal sleeve and stems. Tobramycin-and-gentamicin-impregnated cement was used for this procedure (Fig. 3). The incision was closed primarily with the use of an incisional vacuum dressing.
Figure 3: Anteroposterior (A) and lateral (B) radiographs of the right knee after reimplantation using distal femoral replacement and tibial metaphyseal sleeve with stems.
At 2 weeks postoperatively the patient developed wound drainage and medial skin breakdown that required open irrigation and debridement and exchange of bearing and hinge components with placement of Stimulan® (Biocomposites, Inc., Wilmington, NC) dissolvable vancomycin antibiotic beads (Fig. 4). Intraoperative cultures grew Enterococcus faecalis, and the patient is now on long-term amoxicillin–clavulanate oral suppression.
At most recent follow-up (11 months after reimplantation), the patient walks without a limp; uses a cane only for long distances; and has a healed incision with no effusion, ROM of 0° to 90°, no extensor lag, and no instability on examination (Fig. 5).
Figure 4: Anteroposterior radiograph of the right knee after irrigation and debridement and placement of dissolvable antibiotic beads.
Figure 5: Standing anteroposterior radiograph of both knees at final follow-up.
Revision TKA in the setting of recurrent PJI presents a challenge for infection eradication and joint reconstruction, requiring aggressive debridement of bone, including intramedullary canals, and soft tissues. It is critical to optimize the soft-tissue envelope for adequate coverage. In this case, the skin was in poor condition due to chronic drainage from PJI and 7 surgeries. Rotational flap coverage should be considered when the skin cannot be closed primarily. A static antibiotic cement spacer was used in our patient to treat infection and allow the tissues to recover after debridement and excision of the draining sinus tract . A systematic review by Pivec et al. found that static spacers were associated with decreased ROM compared to articulating spacers (92° versus 100°) , but both types of 2-stage revisions had similar improvements in Knee Society Score and no difference in re-infection, complication, or revision rate .
A failed 2-stage revision for recalcitrant PJI poses significant risk for another failure if the host is not optimized and there is a resistant organism . Vadiee et al. reported success in eradicating infection in 74% of 148 cases after repeat 2-stage revision at a mean of 4 years . Our patient had extensive bone loss requiring the use of a distal femoral replacement and tibial metaphyseal sleeve for fixation. The use of a tumor type of prosthesis reconstruction in non-oncologic revision TKA is associated with a 28% PJI rate and up to 37% complication rate [1, 3]. It is important to counsel patients on the risk of complications in repeat 2-stage revision, including refractory infection and bone loss requiring prosthesis reconstruction. Nonetheless, acceptable outcomes can be achieved with optimization of host-related risk factors, careful soft-tissue management, and identification of a susceptible organism.