Vascularized Bone Grafting for the Treatment of Capitate Avascular Necrosis

Avascular necrosis (AVN) of the capitate bone is a rare condition and it can be related to major trauma or idiopathy. Different treatments are available including soft tissue interposition and intercarpal arthrodesis including lunocapitate, scaphocapitate, four corner, and carpometacarpal fusions. Other surgical options are resection of the proximal pole and revascularization procedures. The main purpose of this article is to present two cases of AVN of the capitate treated with a revascularization procedure using the 4th-5th extensor compartment artery (4th-5th ECA). Two female patients with capitate AVN are reported with an average age of 30.5 years. Both cases were classified as type-I according to Milliez classification. The major complaint in each case was wrist pain that increased during activity. In both cases there was no history of trauma, smoking, diabetes, or hematologic diseases. Both patients had a diminished range of motion, grip, and strength. The definitive diagnosis was made with magnetic resonance imaging. Both patients underwent treatment revascularization of the capitate using a vascularized bone graft based on the 4th-5th ECA. At average follow-up of 12 months, each patient had improved with regards to pain and had increased grip strength. The literature does not describe a specific algorithm treatment for capitate AVN. We recommend revascularization of the capitate using the 4th-5th ECA in type-I Milliez classification in young patients without signs of carpal collapse.

Intra- and Inter-observer Variability in Different Methods of Measuring Carpal Collapse

Introduction: Carpal collapse of wrist occurs in disorders like rheumatoid arthritis and Kienbock's disease. Three techniques have been described to measure carpal collapse. First, the carpal height ratio (CHR), measured by dividing carpal height by 3rd metacarpal length. Second, the revised carpal height ratio (RCH ratio), measured by dividing carpal height by length of capitate. Third, capitate radius distance (CR index), measured by shortest distance between distal edge of radius and the proximal edge of capitate. The index publications describe good reliability of all these but which method out of the three is best in terms of intra- and inter-observer variability is not known. The purpose of this study was to find out which method had the least inter- and intra-observer variability for determining carpal collapse.

Materials and Methods: Fifty normal wrist postero-anterior radiographs were studied by three assessors who measured CHR, RCH ratio and CR index separately. The measurements were repeated after one month by all the three observers. The results were then statistically analysed.

Results: The p-value was <0.001 in all the three assessors in CR index meaning that the intra-observer variability was least in CR index. For the inter-observer variability intra class coefficient of 0.9 indicated that the CR index has the least variability.

Conclusion: CR index is the most reproducible method to measure carpal collapse. The method which provides accurate measurement of carpal collapse will allow better staging of carpal disorders.