Complex Primary Total Knee Replacement (TKR) Using Prophylactic Gastrocnemius Flap and Rotating-Hinge Knee in Post-traumatic, Infective Arthritis of the Knee – A Case Report

INTRODUCTION: Prophylactic gastrocnemius flap with primary rotating hinge knee is technically demanding in a case of neglected post-traumatic, infective arthritis of the knee, with challenges of compromised skin and soft tissues, articular bone defect, limb mal-alignment, gross instability, retained hardware and a contracted extensor mechanism with the patella fixed in the lateral gutter all in combination, is rarely reported. We report such a complex case in this study. CASE REPORT: We report a 48 year male patient with a history of fracture lateral femoral condyle of right knee due to road traffic accident 10 years back, for which he got operated with open reduction and internal fixation with cancellous screws, which subsequently got infected. Primary procedure undertaken was removal of implants, debridement, placement of antibiotic-cement spacer followed by prophylactic medial gastrocnemius flap and a temporary joint spanning external fixator. Definitive procedure undertaken, after clearance of infection in 12 weeks was conversion to a rotating hinge TKR using a lateral para-patellar arthrotomy & tibial tubercle osteotomy to address the challenges of fixed patella in the lateral gutter and contracted ligamentum patellae. At one year follow up, the knee was painless, stable, with satisfactory range of motion and improved function without any infection or aseptic lysis. CONCLUSION: Prophylactic Gastrocnemius flap cover along with rotating hinge knee arthroplasty using a lateral para-patellar approach and tibial tubercle osteotomy in a case of neglected post-traumatic, infective arthritis of knee with the complexities of limb mal-alignment, compromised skin and soft tissue, articular bone loss and ligamentous instability is a satisfactory bail out option in such a highly complex joint scenario.