A Cadaver Investigation of Screw Purchase with 2 Retrograde Techniques for Capitolunate Arthrodesis

Purpose To examine the hypothesis that the amount of bone purchase within the lunate is greater when using a technique for intermetacarpal retrograde screw placement across the capitolunate joint than when using a dorsal capitate technique. Methods Seven fresh cadaver limbs were dissected. We exposed the carpus and scaphoidectomy and performed selective capitolunate decortication. We compared the technique of dorsal capitate placement of headless compression screws with intermetacarpal placement by measuring the depth of purchase in the lunate. Results Drill hole depths in the lunate were greater using the intermetacarpal technique versus the dorsal capitate technique; the average depth was 9.0 and 6.4 mm, respectively. The calculated number of threads was also greater with the intermetacarpal technique than with the dorsal capitate technique (15 vs 9 threads, respectively). Conclusions The intermetacarpal technique for retrograde headless compression screw placement in a capitolunate arthrodesis provided a greater depth of purchase in the lunate portion of the construct. It also afforded more ease of placement than previously described antegrade techniques without the risk of hardware migration into the radiocarpal joint. Clinical relevance The knowledge gained from this study may help guide surgeons to choose a technique for retrograde placement of headless compression screws in capitolunate arthrodesis to gain better purchase within the lunate.