Session VIII - Pelvis

Superior Pubic Ramus Fractures Fixed with Percutaneous Screws: What Predicts Fixation Failure?

Tetsuya Nakatani, MD¹; Adam J. Starr, MD²; Kevin B. Cederberg, MD³; Charles M. Reinert, MD; Alan L. Jones, MD²; (n-all authors)

¹Kobe University Graduate School of Medicine, Kobe, Japan;

²Department of Orthopaedic Surgery, University of Texas Southwestern Medical Center, Dallas, Texas, USA;

³Department of Radiology, University of Texas Southwestern Medical Center,

Dallas, Texas, USA

Purpose: This study was conducted to present early complications of percutaneous screw fixation of superior pubic ramus fractures and a new classification scheme for superior pubic ramus fractures.

Methods: 112 patients underwent percutaneous screw fixation of 145 superior ramus fractures. Their average age was 36 years. A classification of superior ramus fractures was devised: 22 fractures were classified as type 1, fracture extending medial to the obturator foramen; 100 were type 2, fracture within the medial and lateral borders of the obturator foramen; and 23 were type 3, fracture extending lateral to the obturator foramen. Ramus fracture displacement averaged 7.3 mm. Closed reduction succeeded in 113 cases; percutaneous reduction was employed in 32 cases. 56 fractures were repaired using antegrade screws; 89 retrograde. 106 underwent simultaneous posterior ring stabilization. Average blood loss, fluoroscopy and operating room time for the procedures were 33 ml, 8 minutes, and 71 minutes, respectively. Post-operative fracture displacement average 3.7mm.

Results: Overall follow-up averaged 7 months. 11 of 112 patients (10%) lost reduction prior to fracture union; their average age was 54 years. 10 patients were women. 10 had lateral compression fracture patterns, one with a vertical shear fracture. In 9 cases, reduction loss involved recurrence of the internal rotation deformity noted on injury radiographs. Reduction loss at the ramus always coincided with reduction loss posteriorly. 10 patients with reduction loss had retrograde screws. 9 fractures that lost reduction were type 2; 2 were type 1. Two patients had screw back out without reduction loss. Another patient developed delayed union. One patient with reduction loss developed nonunion. One patient underwent
repeat percutaneous fixation after loss reduction loss. Another patient whose screw backed out underwent elective hardware removal.

Significance/Conclusions: Percutaneous fixation of superior ramus fractures did not result in damage to surrounding neurologic, urologic, or vascular structures. Reduction was maintained in 90% of cases. Reduction loss was most common in elderly women, and was noted only in type 1 and 2 fractures. These patients' osteopenia, coupled with the sparse bone available in type 1 and 2 fractures, combined to create conditions for failure. When treating an elderly patient with a type 1 or 2 pubic ramus fracture, surgeons should consider other fixation methods.