[Static stress of tibiofibular syndesmosis]

The tension-patterns of the tibiofibular syndesmosis during stance and push-off phases of gait are still unknown. Therefore a strain-gauge study was done, using an anatomically prepared human leg with the syndesmosis removed and the gauges fixed on the bone, avoiding bending influences. Syndesmotic tension forces measured under sequential axial loading up to 500 N in neutral ankle position were 6.5 N for anterior and 10 N for posterior ligaments under maximum load. With 10 degrees ankle dorsiflexion and no load applied about 5 N of tension were measured in each of the anterior and posterior ligaments. Application of axial load under same conditions resulted in a decrease to negligible tension in the anterior ligament and an increase of tension in the posterior ligament. In evaluating the load tests, which were done in 10 degrees dorsiflexion and the so-called neutral-zero-position of the ankle, we found that our data correlated well with the elasticity and tearing resistance, measured by Sauer. According to the pathomechanics of trauma exact measurements of these forces in the weightbearing ankle are of interest for postoperative treatment of ankle fractures.