Free Vascularized Medial Femoral Condyle Structural Flaps for Septic Terminal Digital Bone Loss

A unique clinical problem exists when the majority of distal bone stock in a digit is destroyed by osteomyelitis, leaving a residual soft tissue envelope with tenuous, random perfusion surrounding a nidus of scar tissue. Pulp pinch is lost in the absence of bony support, and limited options exist. Apart from toe transfer or revision amputation with shortening, non-vascularized bone grafting inside the residual soft tissue envelope risks graft resorption and reactivation of infection. The purpose of this investigation was to evaluate the clinical outcomes of free vascularized medial femoral condyle structural bone flaps to restore lost pulp pinch in such cases. Nine patients (8 males, 1 female) with a mean age of 43 years sustained extensive terminal bone loss near digital tips following osteomyelitis. The mean length of bone defect was 28 mm (± 8.4). The patients were reconstructed at a mean of 12 weeks from initial trauma/infection, having undergone a mean of two prior surgeries. A structural block of vascularized bone from the medial femoral condyle replaced the missing bone at the digital tip defect, temporarily fixed with K-wires. The bone flap was encased by the residual soft tissue envelope after removing scar tissue from the prior trauma and infection. All bone flaps incorporated fully, restoring pulp pinch function to the respective digits with a mean time to union of 8.6 (± 2.1) weeks; range 6-11 weeks. With few alternative solutions able to address this unique and difficult problem, the structural block of vascularized bone proved able to resist resorption, nonunion, and reactivation of infection; the problems normally encountered under this scenario.