Lateral Ulnar Collateral Ligament Reconstruction: An Analysis of Ulnar Tunnel Locations.

We conducted a study to determine precise ulnar tunnel location during lateral ulnar collateral ligament reconstruction to maximize bony bridge and graft construct perpendicularity. Three-dimensional computer models of 15 adult elbows were constructed. These elbow models were manipulated for simulated 4-mm tunnel drilling. The proximal ulna tunnels were placed at the radial head-neck junction and sequentially 0, 5, and 10 mm posterior to the supinator crest. The bony bridges created by these tunnels were measured. Location of the humeral isometric point was determined and marked as the humeral tunnel location. Graft configuration was simulated. Using all the simulated ulna tunnels, we measured the proximal and distal limbs of the graft. In addition, we measured the degree of perpendicularity of the graft limbs. The ulnar tunnel bony bridge was significantly longer with more posterior placement of the proximal tunnel relative to the supinator crest. An increase in degree of perpendicularity of graft to ulnar tunnels was noted with posterior shifts in proximal tunnel location. Posterior placement of the proximal ulna tunnel allows for a larger bony bridge and a more geometrically favorable reconstruction.