title: Arthroscopic Measurement of Cartilage Lesions of the Knee Condyle: Principles and Experimental Validation of a New Method.
abstract: OBJECTIVE
  To present a new method of arthroscopic measurement of the surface and location of condylar lesions.
  
  
  METHODS
  We propose measuring the height of the condylar lesion by using the lesion's arc (Δ°) obtained from the difference between the angle of flexion at the beginning of the lesion and the angle of flexion at the end of the lesion. The first goal of the study was to determine the intra and inter reliability of the lesion's arc. Experiment 1: 20 deep lesions were evaluated using the lesional arc by two arthroscopists. Experiment 2: In a second series of 20 lesions, the flexion angles of the knees were recorded using a goniometer. All 10 knees (5 in each series) were then disarticulated and the true lesion arc was checked with a goniometer to assess the validity of the scopic measurements. The second goal was to obtain the height of the lesion from the lesion's arc. The lesion arc Δ° of the condylar is converted into height (millimeters) on the basis of a table obtained from 5 standard profiles of the lateral X-ray of the knee.
  
  
  RESULTS
  Experiment 1: The intra observer reliability was good but the inter observer reliability was poor. Experiment 2: The intra and inter observers' reliability were good. On the anatomic control after disarticulating the knee, the confidence interval was narrower when using the goniometer.
  
  
  CONCLUSIONS
  We propose a simple, reliable method to measure the height of a condylar lesion with the lesion's arc during arthroscopy.
authors.affiliation: North Mayenne Hospital, Department of Orthopaedic Surgery, Mayenne, France.
authors.forename: Henri
authors.initials: H
authors.lastname: Robert
authors.affiliation: Hospital Sud, Department of Orthopaedic Surgery, Rennes, France.
authors.forename: Jean Christophe
authors.initials: JC
authors.lastname: Lambotte
authors.affiliation: DBIM, Hopital St Louis, 1 avenue Claude Velfaux, 75010, Paris, France.
authors.forename: Rémi
authors.initials: R
authors.lastname: Flicoteaux
keywords: arthroscopy; cartilage defects; cartilage measurement; osteoarthritis