Nonunion and secondary reduction loss complicate open
distal femur fractures with bone loss. The authors hypothesized that locking plates decrease subsequent
bone grafting yet maintain alignment and immediate postfixation radiographic features predict primary union. A retrospective chart/radiographic review was performed at a Level 1 university trauma center. Thirty-four adults with 36 open AO/Orthopaedic
Trauma Association (AO/OTA) C-type
distal femur fractures were studied. All fractures were treated with open reduction, internal fixation with a lateral locked implant with or without
antibiotic beads, and subsequent
bone grafting. Union required radiographic bridging callus on at least 2 of 4 cortices. Alignment was assessed on initial and united radiographs.
Antibiotic beads within a metaphyseal defect defined clinically important bone loss. Eleven (55%) of 20 fractures with bone loss underwent staged
bone grafting to achieve union vs 2 (13%) of 16 fractures without bone loss.
Antibiotic bead presence was associated with staged
bone grafting (P<.01). Of those with bone loss and grafting, 3 had posterior cortical bone loss only, 3 had medial and posterior cortical bone loss, and 5 had segmental defects. Of 9 fractures with bone loss not requiring grafting, all had radiographic posterior cortical contact and 7 had radiographic medial cortical contact. Posterior cortical continuity was associated with
injuries not requiring bone graft (P<.001). Thirty-four had accurate frontal plane reductions and 35 had accurate sagittal plane reductions. Despite metaphyseal bone loss, locking plates obviate the need for routine
bone grafting of some open
distal femur fractures. Those with radiographic posterior cortical contact are strongly correlated with primary union.