Optimizing Drill Guide Positioning for Foveal Targeting in Arthroscopic One-Bone Tunnel Triangular Fibrocartilage...

To determine optimal drill guide positioning over the articular disc of the triangular fibrocartilage complex (TFCC) for accurately targeting the foveal insertion of the TFCC during arthroscopic one-bone tunnel transosseous repair using radiographic and magnetic resonance imaging (MRI)-based analysis.

A retrospective review was conducted on 60 patients who underwent arthroscopic one-bone tunnel TFCC repair for Palmer type 1B foveal tears. Postoperative radiographs were analyzed to measure the bone tunnel's starting point, angle relative to the ulnar shaft, and tunnel length. These parameters were then used to set the expected position of the drill guide tip over the articular disc of the TFCC on preoperative MRI scans.

The mean starting point of the bone tunnel was 12.0 mm proximal to the ulnar styloid tip, with an average tunnel angle of 37.0° and length of 10.0 mm. MRI analysis localized the drill guide tip approximately 4.0 mm radial to the medial aspect of the ulnar styloid over the articular disc of the TFCC. This location corresponded to the lateral one-third of a line connecting the center of the sigmoid notch to the center of the ulnar styloid process under the radiocarpal arthroscopic view.

These radiologic and anatomic parameters provide a guide for positioning the TFCC drill guide during arthroscopic one-bone tunnel repair. Targeting the lateral one-third of a line between the center of the sigmoid notch and ulnar styloid under the radiocarpal arthroscopic view offers a practical landmark to optimize bone tunnel placement for targeting the foveal insertion of the TFCC.