Correlation between risk factors and healing times in long bone nonunions treated with corticoperiosteal flap from the medial femoral condyle

Background:  The rate of fracture nonunion varies depending on the anatomical site. Numerous procedures have been proposed to treat recalcitrant nonunions. The vascularized medial femoral condyle corticoperiosteal free flap (MFCCFF) is increasingly used in nonunions with small bone loss.The percentage of success of the MFCCFF is high but the factors involved in delayed bone healing or failure of this technique or the contraindications are not described in the literature.This multicentric study aims to identify and report the different factors involved in determining the time of bone healing in the treatment of atrophic nonunion of long bones with the vascularized medial MFCCFF. Methods:  All patients who underwent vascularized medial MFCCFF from January 2011 to December 2020 for the treatment of recalcitrant atrophic nonunions of long bones. Patients were reviewed at 2 and 6 weeks, and 3, 6, and 12 months postoperatively and evaluated by physical and radiographic examinations and patient-reported outcome measures. Results:  The final study population comprised 59 patients with a mean follow-up of 26.2 ± 7.6 months, a rate of bone healing of 94.9% with a mean radiographic bone healing time of 4.1 ± 1.3 months, and low morbidity of the donor site. Diabetes mellitus, a body mass index (BMI) ≥30 kg/m2, and ≥2 previous surgeries on the fracture site were factors predicting timing for bone healing at the multivariate analysis. Conclusion:  This study demonstrates the MFCCFF as an effective and safe procedure for the treatment of the recalcitrant atrophic nonunion of long bones. An association was found between the lengthening of bone healing time and a high BMI, presence of ≥2 previous surgical interventions, and diabetes mellitus, indicating these comorbidities as risk factors (not absolute contraindications) for this microsurgical treatment. So, to our knowledge, the MFCCFF could be the first-choice treatment for atrophic nonunion of long bones.