Antegrade Insertion Allows for Superior Screw Positioning During Fixation of Scaphoid Waist Fractures
Ludovico Lucenti, MD1; Kevin F Lutsky, MD2; Christopher Jones, MD3; Kazarian Erick, MD4; Lauren Banner, MS5; Daniel Fletcher, MD5; Pedro K Beredjiklian, MD6
1Vittorio Emanuele Hospital, Catania, Italy, 2The Rothman Institute, Philadelphia, PA, 3Orthopaedics, Rothman Institute at Thomas Jefferson University Hospital, Philadelphia, PA, 4Harvard University, Boston, MA, 5Rothman Institute, Philadelphia, PA, 6Rothman Institute, Philadelphia, PA
Scaphoid waist fractures are often treated with open reduction and internal fixation using headless compression screws. Both volar and dorsal approaches have been described, with pros and cons of each surgical approach, including mechanical stability and ease of anatomic visualization, among others. Regardless of surgical approach, several biomechanical studies have demonstrated that optimal mechanical fixation is achieved when the screw is positioned along the central aspect of the bone both in the PA and lateral planes. The purpose of this study is to compare differences in screw position using antegrade or retrograde screw fixation of scaphoid waist fractures as it relates to central screw placement.
MATERIALS AND METHODS
We conducted a retrospective evaluation of all patients who had surgery for acute scaphoid waist fractures with headless screw fixation at our institution during an eight year span. A total of 365 patients were identified, and 88 patients, 44 treated with a volar (retrograde screw placement) and 44 with a dorsal (antegrade screw placement) approach, were selected using a random number generator. The surgeon group consists of fourteen fellowship trained hand surgeons, and the choice of surgical approach was at the surgeons' discretion.
Postoperative radiographs were then reviewed by four observers (two fellowship trained Hand surgeons, one fellow, and one orthopaedic resident). Each observer rated screw location in the proximal pole, waist, and distal pole as follows: In the PA view as central (c), radial (r), or ulnar (u); In the lateral view as central (c), volar (v), or dorsal (d). (Figure 1) Each observer performed a total of 528 measurements. Intra- and interobserver reliability were calculated.
Twenty-two patients (50%) in the antegrade group had central screw placement in all three scaphoid regions in both PA and lateral planes compared to four (9.1%) in the retrograde group, a difference which was statistically significant (p>0.0001). For the antegrade group, the screw was central in 227 of 264 zones (85.6%) compared to 121 of 264 (45.8%) in the retrograde group (p>0.0001). Intra- and interobserver agreement was substantial or excellent for all observers.
The dorsal antegrade approach appears to allow the surgeon to achieve central screw placement along all three scaphoid regions during fixation of scaphoid waist fractures.
Figure 1 – (A) Antegrade screw position centrally along all three scaphoid regions; (b) retrograde screw positioned non-centrally (radial/volar in the distal pole, ulnar location in the proximal pole).
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