Fresh Distal Tibial Allograft: An Updated Graft Preparation Technique for Anterior Shoulder Instability

Figures

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  Fig 1. The distal tibia graft should be positioned over the post so that the deepest portion of the sulcus is in line with the center of the post. This will ensure that the graft is cut congruently and allow for best match with the anterior glenoid.

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  Fig 2. When the graft is positioned, it should be rotated so that the surgeon is facing the lateral aspect of the graft. Prior to placing the cutting blocks and performing graft cuts, the cartilage margins should be marked to ensure the prepared graft has a stable cartilage margin.

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  Fig 3. With the graft positioned, a parallel drill guide with extension is placed so that the extension is flush with the cartilaginous surface and at the deepest portion of the sulcus. This will prevent the screws from being placed too close to the articular surface, which may result in screw penetration.

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  Fig 4. The fourth cutting block will have four total cutting slots; two “outer” slots closest to the edge of the block and two “inner” slots closer to the center of the block. The cutting slots will set the superior to inferior length of the graft. With this block fixed, there are three different sized grafts, which can be cut: A 23-mm graft can be cut using both the outer cutting slots (red line); an 18-mm graft can be cut using both of the inner cutting slots (blue line); and a 21.5-mm graft can be cut by using the outer slot on one side of the block and the inner slot on the other side of the block.

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  Fig 5. The completed distal tibia allograft will have two 4.0 mm drill holes through the center in an anterior to posterior direction. The graft surface which will be placed against the native glenoid will be angled, based on cutting block used. The new anterior glenoid rim will correspond to the lateral surface of the distal tibia. (A-C) Multiple views of the prepared distal tibia allograft can be seen.