Condylar Neck Fractures: Lag Screw Plates

16 Condylar Neck Fractures: Lag Screw Plates

Juergen Reuther

Introduction

Reliable fixation and sufficient fragment stability cannot always be achieved with lag screws and plates (Petzel, 1982; Hidding, Wolf and Pingel, 1992; Krenkel, 1994; Ziccardi, Schneider, and Kummer, 1997), due to the aforementioned variations in bone thickness in the ascending ramus. To address this problem a combination of lag screws and miniplate rigid fixation using special instruments has been developed. The advantages of the technique are highlighted here.

The gliding hole in the lag screw plate allows the screw to be moved to ensure better interfragmentary compression. The plate is secured at a distance of 5–8mm from the fracture line, at the posterior border of the ramus. The guide sleeve at the upper end of the lag screw plate has an angle of inclination of 10° to the bone surface. The lag screw is inserted through this guide sleeve into the small fragment, thus securing it to the larger fragment.

Technique

In slightly displaced condylar neck fractures the large fragment is exposed by an extraoral approach. It is slightly contoured from a buccal direction with a bone burr and then milled with a diamond-coated grooved cutter, with the groove pointing to the center of the small fragment and parallel to the posterior border of the ramus (Fig. 16.1). The plate is pre-fixed in the milled recess with a fixation screw in the middle portion of the gliding hole. The distance of the plate from the fracture gap is determined by the thickness of the condylar neck and by the 10° angle of inclination of the guide sleeve. As a rule, this distance is 5–8 mm, which presupposes a condylar neck thickness of approximately 5 mm in the area of the fracture. Then the condylar neck fracture is reduced. The medulla of the small fragment is pre-drilled with a twist drill through the guide sleeve in the plate (Fig. 16.2

Only gold members can continue reading. Log In or Register to continue