Validation of a classification system for acetabular chondral lesions identified at hip arthroscopy in patients with femoroacetabular impingement

J Bone Joint Surg [Br] 2011;93-B:332-336.
Significant recent advances have been made in the understanding and management of femoroacetabular impingement and of the associated pathology of the articular cartilage and the labrum. We have developed a classification system for the chondral lesions of the acetabulum. In our system we use six zones of the acetabulum, which have been described previously by Ilizaliturri and colleagues. The cartilage is then graded on a scale of 0 to 4 as follows: grade 0, normal articular cartilage; grade 1, softening or the “wave sign”; grade 2, fissuring of the cartilage; grade 3, delamination of the cartilage flap from the subchondral bone; grade 4, exposure of the subchondral bone. The site of the lesion was further classified as A, B or C according to whether it lay less than one third of the distance from the acetabular rim to the acetabular fossa, between one third and two thirds of that same distance, or more than two thirds of the distance, respectively. In order to validate the classification system, six surgeons graded ten arthroscopy video recordings.
Our findings showed high intraobserver reliability for the classification system, with an intraclass correlation coefficient of the order of 0.81, and high interobserver reliability with an intraclass correlation coefficient of 0.88.
We have developed a simple, reproducible classification system for lesions of the articular cartilage of the acetabulum, and we hope it will allow standardisation in the recording of articular cartilage lesions, particularly when these are associated with femoroacetabular impingement.