title: Clinical implications of impingement of the anterior femoral cortex after cephalomedullary nailing.
abstract: BACKGROUND
  Cortical impingement is a common complication after cephalomedullary nailing, but the evidence about its consequences is very limited. The aim of this study was to assess the clinical implications of cortical impingement on patients treated with cephalomedullary nails.
  
  
  METHODS
  A cohort study was carried out at a Level I academic Institution with consecutive patients treated with cephalomedullary nails during 2010 and 2013. Demographic and nail variables were recorded as well as cortical impingement was determined on the radiographs. Clinical outcomes such as pain, femoral fractures, and delayed or nonunion of the fracture were detected during the follow-up. The follow-up was divided into short- (6-12 months), medium- (12.1-36 months), and long-term follow-up (≥36.1months). Descriptive statistics were used, and Chi-square or Fisher's exact tests measured the association between categorical variables. The Mann-Whitney U test was performed to evaluate differences between cortical impingement in terms of pain, and pain and the follow-up categories.
  
  
  RESULTS
  A total of 119 patients were analyzed with a mean age of 74.8 years±17.1, and a mean follow-up of 23.5 months±12.1. Overall the pain was present in 61 (51.2%) cases, and it was observed in 28/59 (47.4%) and 33/60 (55%) of the patients with presence or absence of cortical impingement respectively. There was not a statistically significant association between cortical impingement and pain (p=0.20), neither differences were detected between pain and the follow-up groups (p=0.48). Out of 59 cases with cortical impingement, femoral fractures were observed in two patients (3.3%), and delayed union of the fractures was seen in two patients who did not present impingement. Since patients with delayed union received treatment as soon as it was diagnosed, no cases of nonunion of fractures were identified.
  
  
  CONCLUSIONS
  Cortical impingement of the anterior cortex of the femur was not associated with the presence of pain, so that other causes should be assessed to explain the pain after 6 months of being treated with a cephalomedullary nail. Femoral fractures, and delayed union or nonunion of the fracture may occur theoretically in patients with cortical impingement.
authors.affiliation: Department of Orthopaedics & Traumatology, Hospital Universitario de La Samaritana, Bogotá, Colombia.
authors.forename: Omar R
authors.initials: OR
authors.lastname: Peña
authors.affiliation: Department of Orthopaedics & Traumatology, Hospital Universitario de La Samaritana, Bogotá, Colombia.
authors.forename: Amparo
authors.initials: A
authors.lastname: Gómez Gélvez
authors.affiliation: Department of Orthopaedics & Traumatology, Hospital Universitario de La Samaritana, Bogotá, Colombia. Electronic address: kristianesga@yahoo.com.
authors.forename: Kristian A
authors.initials: KA
authors.lastname: Espinosa
mesh_terms: D000368:Aged; D001858:Bone Nails; D005260:Female; D057925:Femoracetabular Impingement / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology; D005264:Femoral Fractures / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D005594:Fracture Fixation, Intramedullary / Q000009:adverse effects / Q000379:methods*; D006801:Humans; D008297:Male; D010146:Pain / Q000209:etiology* / Q000503:physiopathology; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000209:etiology* / Q000517:prevention & control; D011859:Radiography; D012189:Retrospective Studies
keywords: Cephalomedullary nails; Clinical implications; Impingement; Pain