Proximal tibial replacement in revision knee arthroplasty.
A 59-year-old female with morbid obesity , fibromyalgia, obstructive sleep apnea, and lymphedema presented for treatment of her right knee after 4 prior arthroplasty procedures. She underwent bilateral primary TKA 10 years before. After 3 years, she presented with knee pain and instability. Radiographs demonstrated tibial loosening and laboratory tests and aspiration were inconsistent with periprosthetic joint infection (PJI). She underwent revision to a constrained prosthesis. Five years later, the patient underwent another full revision for loosening of the femoral and tibial components . Inflammatory markers were normal. After 2 years, she presented with increasing activity-related pain, swelling, and instability. Examination revealed a draining wound distal to her incision overlying the proximal tibia.

Radiographs demonstrated evidence of tibial component loosening . The patient initially underwent resection arthroplasty with placement of a static antibiotic cement spacer . The surgeon noted a 10-cm uncontained segmental defect of the proximal medial tibia with an intact tibial tubercle. After 2 months and intravenous antibiotics, the patient had a persistent draining despite the spacer

Surgical intervention
The patient underwent spacer exchange and simultaneous wound coverage, with a medial gastrocnemius flap incorporated into the distal arthrotomy closure by plastic surgery. Infectious disease consultation recommended 6 weeks of intravenous antibiotics. The knee incision healed completely.

Four months later, the patient underwent revision TKA . The flap was elevated as part of a medial parapatellar arthrotomy. The smallest available Biomet OSS PTR prosthesis in the anteroposterior plane was chosen to accommodate retention of the intact tibial tubercle and anterolateral tibial cortex. The tibial canal was reamed, and a burr was used to prepare the proximal diaphysis rather than a facing reamer to avoid disrupting the tubercle. An 11 × 225-mm cemented stem was selected to bypass a distal third diaphyseal lateral cortical defect. The tubercle was secured to the prosthesis using two 18-gauge wires. On the femoral side, the Biomet OSS 3-cm standard DFR prosthesis was used with a small OsteoTi metaphyseal sleeve augment and a cemented 90-mm stem.

Postoperative course
The patient was toe touch weight bearing in a knee immobilizer for 2 weeks. The immobilizer was discontinued, Her incision healed without complication. Infectious disease recommended long-term prophylactic oral antibiotic therapy (doxycycline). Her lymphedema was treated with compression wrapping techniques. At the latest follow-up visit (1.5 year after operation), she is pain-free and ambulating unassisted . Active range of motion is 0 to 90 degrees without extensor lag.