title: Radiographic classification of the femoral intercondylar notch posterolateral rim.
abstract: OBJECTIVE
  The purpose of this study was to determine whether posterolateral rim morphology can be delineated on plain radiographic images.
  
  
  METHODS
  We obtained 20 femora from the Cleveland Museum of Natural History (10 each with distinct and indistinct posterolateral rims). Four blinded reviewers evaluated radiographic posterolateral rim morphology on lateral radiographs. The reviewers included a musculoskeletal radiologist, a fellowship-trained sports medicine surgeon, a pediatric orthopaedic surgeon, and a junior orthopaedic resident. Interobserver and intraobserver reliability was determined.
  
  
  RESULTS
  Radiographically, posterolateral rim morphology was classified into 2 types. Type 1 rims have a defined transition from Blumensaat's line to the posterior femoral cortex. Type 2 rims have an indistinct transition. Interobserver reliability showed substantial agreement during the first (kappa = 0.65) and second (kappa = 0.70) sessions. Intraobserver reliability was nearly perfect, with kappa values ranging from 0.8 to 1.0.
  
  
  CONCLUSIONS
  It has been shown anatomically that the posterolateral rim has variable morphology. We have shown that posterolateral rim morphology can be delineated on lateral plain film images. Radiographic type 1 rims correlate with distinct posterolateral rim morphology. Radiographic type 2 rims correlate with indistinct posterolateral rim morphology.
  
  
  CONCLUSIONS
  For surgeons who reference the posterolateral rim for femoral tunnel placement during anterior cruciate ligament reconstruction, indistinct posterolateral rim morphology may result in errant tunnel placement. Improved awareness of posterolateral rim morphology preoperatively may help avoid technical errors with placement of the femoral tunnel.
authors.affiliation: Department of Orthopaedic Surgery, The Cleveland Clinic, Cleveland, Ohio 44195, USA. lutulfarrowmd@yahoo.com
authors.forename: Lutul D
authors.initials: LD
authors.lastname: Farrow
authors.forename: Michael R
authors.initials: MR
authors.lastname: Chen
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Cooperman
authors.forename: Donald B
authors.initials: DB
authors.lastname: Goodfellow
authors.forename: Mark S
authors.initials: MS
authors.lastname: Robbin
mesh_terms: D016118:Anterior Cruciate Ligament / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000601:surgery; D001182:Arthroscopy / Q000379:methods; D005269:Femur / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D005270:Femur Head / Q000000981:diagnostic imaging; D005272:Femur Neck / Q000000981:diagnostic imaging; D006801:Humans; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging; D011859:Radiography; D019651:Plastic Surgery Procedures; D013977:Tibia / Q000033:anatomy & histology