Interobserver variance in diagnostic arthroscopy of the knee

The diagnostic interindividual variance of 91 German and Dutch arthroscopists has been assessed by the Kappa Cohen interobserver variation analysis using a videotape with three complete knee arthroscopies with different pathologies. Non-pathological conditions show a moderate to excellent interobserver correlation, whereas pathological changes often show very little correlation, especially the synovial membrane of the suprapatellar recess, the cartilage of the femuropatellar groove, and the posterior cruciate ligament. The patella alignment also shows a high interobserver variability. There are no apparent differences between German and Dutch arthroscopists. When comparing arthroscopic findings with other imaging techniques the above results should be taken into account because the use of arthroscopy as golden standard is challenged. Furthermore, these results will influence the meaningfulness of medical expert witness based only on pictures. Also the medical cost balance based on arthroscopic findings has to take into account that a wrong diagnosis is possible and therefore charged wrong.