In an interdisciplinary project involving electronic
engineers and clinicians, a telemetric system was developed to measure
the bending load in a titanium internal femoral fixator. As this
was a new device, the main question posed was: what clinically relevant
information could be drawn from its application? As a first clinical
investigation, 27 patients (24 men, three women) with a mean age
of 38.4 years (19 to 66) with femoral nonunions were treated using the
system. The mean duration of the nonunion was 15.4 months (5 to
69). The elasticity of the plate-callus system was measured telemetrically
until union. Conventional radiographs and a CT scan at 12 weeks
were performed routinely, and healing was staged according to the
CT scans. All nonunions healed at a mean of 21.5 weeks (13 to 37).
Well before any radiological signs of healing could be detected,
a substantial decrease in elasticity was recorded. The relative
elasticity decreased to 50% at a mean of 7.8 weeks (3.5 to 13) and
to 10% at a mean of 19.3 weeks (4.5 to 37). At 12 weeks the mean
relative elasticity was 28.1% (0% to 56%). The relative elasticity
was significantly different between the different healing stages
as determined by the CT scans. Incorporating load measuring electronics into implants is a promising
option for the assessment of bone healing. Future application might
lead to a reduction in the need for exposure to ionising radiation
to monitor fracture healing.
Sacroiliac screw fixation is the method of choice for the definitive treatment of unstable posterior pelvic ring injuries; however this technique is demanding and associated with a high risk of iatrogenic neurovascular damage. We therefore evaluated the outcome, complications, surgical and fluoroscopy time for unstable posterior pelvic ring injuries managed with a transiliac locked compression plate. 23 patients were managed with a transiliac locked compression plate for unstable posterior pelvic injuries at a Level I Trauma Center. 21 patients were available for follow up after an average of 30 months and outcome evaluation was performed with the Pelvic Outcome Score, which is composed of a clinical, radiological, and social integration part. The overall outcome for the pelvic outcome score was excellent in 47.6% (10 patients), good in 19% (4 patients), fair in 28.6% (6 patients) and poor in 4.8% (1 patient). 15 out of 21 patients (71.4%) returned to their normal life, 3 patients (14.3%) were limited at work, and 3 patients (14.3%) were not able to return to work due to their disabilities. The social status was unchanged to the preinjury status in 19 patients (90.5%). 13 patients (62%) stated no changes in spare time and sports activities; 4 patients (19%) had minor and another 4 patients (19%) had major restrictions. The average operation time was 101 min and intraoperative fluoroscopic time averaged 74.2 sec. No iatrogenic neurovascular injuries were observed. Posterior percutaneous plate osteosynthesis may be a good alternative to sacral screw fixation because it is quick, safe, and associated with a good functional outcome.