Abstract
Gavril Ilizarov advocated a fine wire tension of between 900N and 1200N for circular frame construction. Wire tension can be achieved via a tensioning device or ‘Russian tensioning’ (a fixed wire lengthening around a bolt). There is limited information on the latter technique. This study explored the tensions achieved via Russian tensioning and reports the impact of a second wire on construct tension.
A single 160mm stainless-steel ring was constructed, then 1.8mm stainless steel wires were secured using a Russian fixation bolt and Russian tensioned with a 2nd bolt. The angle subtended by tensioning using the 2nd bolt was measured using a goniometer. Angles of 45°, 70° and 90° were repeated in triplicates, with wire tension measured using a calibrated tensiometer. A second, orthogonal wire was added and tensioned to the same angle. Tensions of both wires were remeasured and recorded. Unpaired t-tests were used to compare mean tensions. A value of p<0.05 was considered significant.
Tensioning at all angles was insufficient to achieve the target range of 900–1200N (range 99–110N). A second, orthogonal wire changed frame dynamics such that a 90° angle resulted in both wires achieving adequate tension (mean 1143N, SD 307N). Increases were significant across all tensioning angles (p=<0.002) however only biomechanically relevant for 90°.
Russian tensioning is insufficient with a single wire, however the addition of an orthogonal wire increases tension in both wires, reaching the target range at 90° deflection. Further study using wire tensioners is warranted, and also the impact of non-orthogonal wire constructs.
