The Ghost in the Machine

​SPECT CT combines nuclear medical imaging (such as bone scans) with CT and gives a colourful image representing tissue metabolism. Problem areas are identified as anatomically precise ‘hot spots’.

At the hand surgery meeting, an Auckland radiologist gave an eloquent presentation on the benefits of SPECT – CT, a helpful attribute in the diagnosis of Kienbocks disease in patients with wrist pain. In 1920 Robert Kienbock, a Viennese radiologist first described a ‘malacia of the lunate’. Other investigators since then have described Kienbock’s disease as ‘a disorder that displays a slow progression with eventual collapse of the lunate and alteration of the surrounding architecture of the carpus (Lichtman et al 2010) Investigators have studied shear forces on the lunate caused by ulna variance, patterns of arterial supply causing avascular necrosis or compromise to venous outflow. It appears evident that the development of Kienbock’s disease is multifactorial.

This poses challenges for management, which attempts to enhance spontaneous revascularisation. This can include immobilisation, surgical revascularisation, indirect joint levelling procedures (radial lengthening or ulna shortening), carpal surgeries to shorten the capitate or intercarpal fusions. The key is in understanding the stage of the disease and anatomy at the time of diagnosis.

Begg & Bain (2006) describe arthroscopic examination as a method of assisting with treatment planning and proposed a classification system, which has been expanded upon in recent literature (Maclean et al 2017).  Chondral, vascular and osseous components are assessed. If the articular surfaces are intact, a synovectomy, radial shortening or capitate shortening is indicated, if the lunate is involved but the lunate facet on the radius is intact, lunate reconstruction or graft or a proximal row carpectomy is indicated. If there is involvement of both the lunate facet and the proximal lunate, wrist fusion could be considered. Concurrent wrist instability problems may also need to be addressed.