Biomechanical evaluation of tension band placement for the repair of olecranon fractures.

Displaced transverse fractures of the olecranon commonly are treated by open reduction and internal fixation using the AO tension band wiring technique. Reports that the AO technique has a tendency to open the fracture site at the articular surface prompted Rowland and Burkhart to modify placement of the tension band. The present study tested the hypothesis that the modified wire placement provides static compression anteriorly, and hence better reduction at the articular surface of the fracture, than the AO technique under static conditions. Transverse olecranon fractures were created on 8 pairs of fresh cadaveric arms. One ulna of each pair was repaired using the modified wire placement, whereas the contralateral ulna was repaired using the AO technique. The humerus was driven into the trochlear fossa of each ulna using a servohydraulic testing machine while a force transducer and video system measured the applied force and gap formation at the articular surface of the fracture. Because the static behavior of the fixations was tested, no muscle forces were included. Results indicated no significant differences in yield loads or stiffness values between the 2 techniques. Based on the results of this static study, the modified wire placement does not provide increased stability of fracture fixation compared with the AO tension band wiring technique.

The miniarthrotomy technique of ankle arthrodesis: a cadaver study of operative vascular compromise and early clinical results.

We present a two-part study of the miniarthrotomy ankle fusion technique for minimally deformed joints: a laboratory investigation of ankle vascularity and a clinical review of the early results. In the laboratory portion, five pairs of cadaver legs were injected with radiographic dye, after which arthrodesis was performed via either the open technique (one leg of each pair) or the miniarthrotomy technique (the contralateral leg of each pair). Two legs in the open arthrodesis group had disruption of the peroneal arterial circulation, but no disruption was identified in the miniarthrotomy group. In the clinical portion of the study, we reviewed the results of 32 patients who had undergone ankle fusion via the miniarthrotomy technique. One patient had a nonunion and two patients had delayed union. The average time to union for the 31 patients was 8 weeks (range: 6 to 22). These results compare favorably to the arthroscopically assisted method of fusion and offers another choice for arthrodesis of minimally deformed ankles. We concluded that with minimal disruption, there is less likelihood of arterial injury and devascularization, which may indirectly have a positive effect on the rate of ankle arthrodesis.