Tape suture for stabilization of incomplete posterior pelvic ring fractures-biomechanical analysis of a new minimally invasive treatment for incomplete lateral compression pelvic ring fractures.

BACKGROUND: Incomplete lateral compression fractures (including AO Type B2.1) are among the most common pelvic ring injuries. Although the treatment of choice remains controversial, sacroiliac (SI) screws are commonly used for the operative treatment of incomplete lateral compression fractures of the pelvic ring. However, the disadvantages of SI screws include the risk of nerve root or blood vessel injury. Recently, tape sutures have been found useful as stabilizing material for the treatment of injuries of the syndesmosis, the rotator cuff and knee ligaments. In this current study, we aimed to test the biomechanical feasibility of tape sutures to stabilize the pelvis in the setting of AO Type B2.1 injury. METHODS: Six human cadaveric pelvises underwent cyclic loading to compare the biomechanical stability of different osteosynthesis methods in a B2.1 fracture model. The methods tested in this experiment were a FiberTape® suture and the currently established SI screw. A 3D ultrasound tracking system was used to measure fracture fragment motion. Linear regression was used to model displacement and stiffness at the posterior and anterior pelvic ring. RESULTS: At the posterior fracture site, the FiberTape® demonstrated similar displacement (2.2 ± 0.8 mm) and stiffness (52.2 ± 18.0 N/mm) compared to the sacroiliac screw (displacement 2.1 ± 0.6 mm, P >  0.999; stiffness 50.8 ± 13.0 N/mm, P > 0.999). Considering the anterior fracture site, the FiberTape® again demonstrated similar displacement (3.8 ± 1.3 mm) and stiffness (29.5 ± 9.0 N/mm) compared to the sacroiliac screw (displacement 2.9 ± 0.8 mm, P = 0.2196; stiffness 37.5 ± 11.5 N/mm, P = 0.0711). CONCLUSION: The newly presented osteosynthesis, the FiberTape®, shows promising results for the stabilization of the posterior pelvic ring in AO Type B2.1 lateral compression fractures compared to a sacroiliac screw osteosynthesis based on its minimal-invasiveness and the statistically similar biomechanical properties.

Clinical tips: retrograde drilling of talar osteochondral defects.

Contemporary methods of bone grafting osteochondral defects, in which the remaining overlying cartilage is relatively well preserved, have inherent problems. The bony defects are often saucer-shaped and the cylindrical graft may not fill the void, leaving areas of cartilage with no underlying scaffold and obviating early weight bearing. Furthermore, to obtain a proper fill of the defect, tamping of the graft can cause excessive pressure and disruption of the overlying cartilage. In an effort to address these concerns, the authors propose the use of a biological viscous paste of calcium sulfate that hardens within 5 minutes when injected in a retrograde fashion into the talus. This confers a mechanical advantage of complete cystic fill of the cyst which allows early weight bearing. Calcium sulfate acts as an osteoconductive material that incorporates into host bone within 8 weeks. Donor site morbidity is eliminated using this system.