LOWER LIMBThe radiographic classification of the bone–screw interface in paediatric tibial lengtheningMcAndrew, Andrew R.a; Saleh, Michaelb c; Rigby, Alan S.d; Donnan, Leo T.eAuthor Information aPortsmouth Hospitals NHS Trust bUniversity of Sheffield cNorfolk and Norwich University Hospital dStatistics and Cardiovascular Epidemiology, Department of Academic Cardiology, University of Hull, UK eRoyal Children's Hospital, Melbourne, Victoria, Australia Correspondence to Mr. Andrew R. McAndrew, 9, Eyre Close, Totton, Southampton, SO40 8TN, UK Tel: +44 2380868994; e-mail: email@example.com Journal of Pediatric Orthopaedics B: September 2007 - Volume 16 - Issue 5 - p 305-311 doi: 10.1097/BPB.0b013e3282ef4e4a Buy Metrics Abstract Bone–screw loosening in monolateral external fixators is a significant problem. This study classifies the radiographic appearance of the bone–screw interface and predicts which screws will become loose and those that will remain solidly fixed to bone. Five radiographic features were identified at the bone–screw interface. The classification of these features was validated using interobserver and intraobserver studies. The reliability of the classification was improved by image enhancement with simple filters. Some radiographic features predicted which screws would eventually become loose, allowing the clinician to make earlier management decisions regarding the adjustment of screws. © 2007 Lippincott Williams & Wilkins, Inc.