RESUMEN
INTRODUCTION: The status of the lateral compartment of the knee is a determining factor in the long-term outcome of medial unicompartmental arthroplasty (UKA). Various methods of assessing the lateral compartment have been used including stress radiography, radioisotope bone scanning, magnetic resonance imaging and visualisation at the time of surgery. Arthroscopy is another means of directly assessing the integrity of the articular cartilage and the meniscus in the lateral compartment. PURPOSE: This study aims to show that per-operative arthroscopy is a safe and effective means of deciding whether to proceed with UKA or convert to total knee arthroplasty (TKA). METHOD: We have used arthroscopy of the lateral compartment to assess suitability for UKA in 151 knees over 8 years. RESULTS: At time of arthroscopy 34 knees underwent a change of surgical plan from UKA to TKA (22.5%). There has been one revision to TKA and 2 bearing exchanges for dislocation. CONCLUSION: Immediate per-operative arthroscopy is a reliable method for assessing the suitability of a knee for UKA, in particular the lateral compartment.