Incidence and Risk Factors of Allograft Bone Failure After Calcaneal Lengthening

Background Calcaneal lengthening with allograft is frequently used for the treatment of patients with symptomatic planovalgus deformity; however, the behavior of allograft bone after calcaneal lengthening and the risk factors for graft failure are not well documented. Questions/purposes (1) What proportion of the patients treated with allograft bone had radiographic evidence of graft failure and what further procedures were performed? (2) What are the risk factors for radiographic graft failure after calcaneal lengthening? (3) What patient factors are associated with the magnitude of correction achieved after calcaneal lengthening? Methods Between May 2003 and January 2014, we performed 341 calcaneal lengthenings on 202 patients for planovalgus deformity, the etiology of which included idiopathic, cerebral palsy, and other neuromuscular disease. Of these, 176 patients (87%) had adequate followup for graft evaluation, defined as lateral radiographs taken before and at least 6 months after the index procedure (mean, 18 months; range, 6–100 months) and 117 patients (58%) had adequate followup for the assessment of the extent of correction, defined as weightbearing anteroposterior and lateral radiographs taken before and at least 1 year after the index procedure (mean, 24 months; range, 12–96 months). These patients’ results were evaluated retrospectively. The Goldberg scoring system was chosen for demonstration of allograft behavior. A score lower than 6 at 6 months after surgery was defined as radiographic graft failure; the highest possible score was 7 points, and this represented graft incorporation with excellent reorganization of the graft and no loss of height. The patient age, sex, diagnosis, graft material, ambulatory status, and use of antiseizure medication were evaluated as possible risk factors, and we controlled for the interaction of potentially confounding variables using multivariate analysis. Additionally, six radiographic indices were analyzed for their effects on the extent of correction. Results The mean estimated Goldberg score was 6 (SD, 1.14) at 6 months after calcaneal lengthening with 11 feet (4%) classified as radiographic graft failure (Goldberg score