Temporary arthrodesis of the knee joint using coupled AO rods

Background: Two-stage revision remains the standard of care for periprosthetic joint infection (PJI) of the knee, typically utilizing either static or articulating antibiotic-impregnated polymethylmethacrylate (PMMA) spacers. While articulating spacers may preserve range of motion, they are often contraindicated in cases involving significant ligamentous instability or extensive metaphyseal bone loss. Conventional static spacers may lead to capsular contracture and limited weight-bearing capacity, necessitating alternative stabilization methods for complex revisions.

Objective: This article describes a surgical technique for temporary knee arthrodesis using intramedullary steel rods and an antibiotic-loaded cement spacer to provide stable fixation and allow early mobilization during the interim phase of a two-stage septic revision.

Key Points: The procedure involves radical debridement followed by the insertion of 12 mm diameter hollow AO steel rods into the femoral and tibial medullary cavities. These rods are joined by a tube-to-tube clamp, fixed in 5 degrees of flexion and 5–10 degrees of internal tibial rotation to optimize patellar tracking. Antibiotic-impregnated PMMA is applied to fill the dead space and distend the joint capsule, preventing soft tissue shrinkage. This construct facilitates immediate weight-bearing as tolerated and reduces the risk of secondary immobilization-related comorbidities. Potential complications include peri-implant fractures, cement extrusion into the posterior compartment, and persistent infection.

Conclusion: Intramedullary stabilization with steel rods and PMMA spacers provides a reliable, cost-effective method for managing complex septic knee revisions. By maintaining limb length and capsular volume, this technique facilitates subsequent reimplantation while allowing functional mobilization during the infection eradication interval.