An Articular-based Approach to Kienbock Avascular Necrosis of the Lunate

Abstract

There are 3 pathologic phases of Kienbock disease: early vascular, intermediate osseous, and late chondral. Most of the earlier investigators have used Lichtman osseous radiologic classification. We have used an articular based approach to assess and manage Kienbock disease. The Bain and Begg arthroscopic classification is based on the number of nonfunctional articular surfaces of the lunate and adjacent articulations. The spectrum of articular changes span from grade 0, all normal articular surfaces; grade 1, involvement of the proximal lunate which is often soft and indentable with a false floor; grade 2a, lunate changes and secondary changes on the lunate facet; grade 2b, coronal lunate fracture produces involvement of the midcarpal joint; and grade 3s and 4, involvement of 3 and subsequently 4 of the perilunate articular surfaces. Arthroscopic findings have shown that radiographs often underestimate articular changes and frequently changed the treatment recommendation. Eighty-two percent of cases had at least 1 nonfunctional articulation, whereas 61% had at least 2 nonfunctional articulations. The aim of surgical treatment is to maintain functional motion with normal articulations. The articular-based classification directs treatment based on sound surgical principles. If all articular surfaces are intact, then a procedure that does not violate the articular surfaces is indicated (eg, synovectomy, vascularized bone graft, forage or joint leveling procedure). With nonfunctioning articular surfaces, an articular reconstructive procedure is required to leave the carpus mobile with only functional articular surfaces. (eg, proximal row carpectomy, radioscapholunate fusion, lunate replacement, or hemiarthroplasty). More extensive joint involvement requires a salvage procedure. This articular-based approach was developed for Kienbock disease but is universally applicable to all forms of avascular necrosis and can be used with advanced imaging modalities.