Stability of Locking and Non-Locking Plates in an Osteoporotic Calcaneal Fracture Model

Till Illert, MD; Stefan Rammelt, MD, PhD; Tim Drewes, MD; Rene Grass, MD

Foot & Ankle International: March 2011 (Vol.32 #3)

Background: The aim of this biomechanical cadaver study of calcaneal

fractures was to investigate whether a locking calcaneal plate provides

more stiffness in osteoporotic bone compared to a non-locking plate.

Materials and Methods: Sixteen fresh frozen bone mineral density

(BMD)-matched cadaver feet were tested in a four-part model of a

Sanders Type IIB calcaneal fracture. The fractures were fixed either

with a non-locking AO (Sanders) plate or an interlocking AO plate

(Synthes, Paoli, PA) to the lateral calcaneal wall with six screws.

Specimens were subjected to cyclic loading which was increased stepwise

to full body weight. Displacement of the posterior facet fragment was

measured with an optical tracking system in the sagittal and transverse

planes. Results: No statistically significant differences were observed

between the non-locking and the locking plates with respect to number

of cycles to failure or 1-mm displacement of the posterior facet. The

initial stiffness was significantly higher for non-locking plates.

Conclusion: In osteoporotic bone, the greater stiffness of the

screw-locking plate construct was offset by the smaller diameter of the

screw threads and the lower friction between the plate and bone when a

locking plate was used. In clinical practice, the plate should first be

compressed to osteoporotic bone with cancellous screws and at least two

screws should be placed in the anterior process and in the tuberosity

of the calcaneus.

Key Words: Calcaneus; Fracture; Locking Plate; Non-Locking Plate;

Biomechanical Properties

Outcomes of Suture Button Repair of the Distal Tibiofibular Syndesmosis

Henry DeGroot, MD, FAAOS; Ali A. Al-Omari, MD; Sherif Ahmed El Ghazaly, MD, FRCS, PhD

Foot & Ankle International: March 2011 (Vol.32 #3) March 1, 2011 

Background: Recently, a suture button device has been advocated as a simple and effective method of repairing the syndesmosis. Proponents of the device have cited earlier weightbearing and elimination of the need for device removal as potential advantages over metallic screws. However, the available reports generally have short followup. With longer followup, some concerns about the suture button device have surfaced. Materials and Methods: We reviewed the clinical and radiographic results of 24 patients with acute injuries to the distal tibiofibular syndesmosis who were treated with suture button fixation. Average followup was 20 months. The primary outcomes measure was the AOFAS ankle hindfoot score. Secondary outcomes measures included a calibrated measurement of the tibiofibular clear space and tibiofibular overlap. Results: The average AOFAS score was 94 points. Syndesmotic parameters returned to normal after surgery and remained normal throughout the followup period. One in four patients required removal of the suture endobutton device due to local irritation or lack of motion. Osteolysis of the bone and subsidence of the device into the bone was observed in four patients. Three patients developed heterotopic ossification within the syndesmotic ligament, one mild, one moderate, and one who had a nearly complete syndesmotic fusion. Conclusion: The suture button device is an effective way to repair the syndesmosis. In our series, the reduction of the syndesmosis was maintained throughout the followup period. However, reoperation for device removal was more common than anticipated. Osteolysis of the bone near the implant and subsidence of the device may occur. 

Level of Evidence: IV, Intervention Case Series

Key Words: Ankle; Syndesmosis; Surgical Treatment