Addition of a Medial Locking Plate to an In Situ Lateral Locking Plate Results in Healing of Distal Femoral Nonunions.

Abstract

Nonunion of the distal femur after lateral plating is associated with axial malalignment, chronic pain, loss of ambulatory function, and decreased knee ROM. The addition of a medial locking plate with autogenous bone grafting can provide greater stability to allow bone healing and may be used to achieve union in these challenging cases. We wished to determine (1) the proportion of patients who achieve radiographic signs of osseous union for distal femoral nonunions with an in situ lateral plate after treatment with addition of a medial locking plate and autogenous bone grafting, and (2) the frequency and types of complications associated with this treatment. Between 2007 and 2013, we treated 22 patients for 23 distal femoral nonunions, defined as an unhealed fracture with no radiographic signs of osseous union at a mean of 16 months (SD, 13 months) after injury. During that time, we used a treatment algorithm consisting of treatment in one or two stages. The single-stage procedure performed in 16 aseptic nonunions with a stable lateral plate involved addition of a medial locking plate and autogenous bone graft. A two-stage treatment performed in seven nonunions with lateral plate failure involved placement of a new lateral locking plate followed by addition of a medial locking plate with autogenous bone graft at least 2 months after the first procedure. Of the 22 patients treated, 20 had a median followup of 18 months (SD, 6-94 months). We defined osseous union by bridging bone on three of four cortices with absence of a radiolucent line or more than 25% cross-sectional area of bridging bone via CT. Twenty of the 21 nonunions attained radiographic signs of osseous union by 12 months. Six of the 20 patients experienced complications: one patient had a persistent nonunion; four patients underwent removal of symptomatic hardware; and one patient experienced skin breakdown at the bone graft harvest site. A very high proportion of patients achieve union when using medial locking plates to treat distal femoral nonunions after lateral plating of the original injury. Addition of bone graft, staged reconstruction, and revision of the initial lateral plate is indicated when the nonunion is associated with fatigue failure of the initial lateral plate. Level IV, therapeutic study.