PubMed2006
OBJECTIVES: Concerning the tension-band principle of internal fixation, this study aims to establish whether any difference in interfragmentary gap exists after bone-reducing forceps are released, when a recommended suture-knot technique and a new technique are tested in vitro on a purpose built machine that features a model of a transverse fracture of the patella. In addition, a standard tension-band wiring technique has also been tested as one form of control. BACKGROUND: Satisfactory compression at a fracture site reduces the risk of failure of fixation, loss of reduction (interfragmentary gap >2mm) and subsequent risks of malunion, delayed union, and ultimately non-union from excessive movement. Stainless-steel wire can provide a stable rigid construct but is associated with complications. Tension-band fixation employing a braided polyester non-absorbable suture provides a less rigid construct. However, satisfactory clinical results and fewer complications are reported. The method by which a suture is tied has an effect on initial compression provided the fracture is reduced. However, it also has an effect on the degree of fracture gap once it is subject to biomechanical distraction. METHODS: By measuring the output of a strain gauge Wheatstone bridge of a purpose built rig that had been calibrated against fracture gap and compression force, the various tension-band fixation techniques as discussed above were evaluated. RESULTS: The tension-band suture technique examined in this work (the modified Wagoner's Hitch) has been evaluated. It has quantitatively shown less fracture gap than other recognised tension-band suture and wire techniques. The results exhibit statistical significance (p<0.001). CONCLUSIONS: This evaluation study has produced quantitative and comparable data of fracture gap as observed with the model of a transverse patella fracture, for both new and established surgical techniques. The contribution this study has made to the knowledge of the subject is that a testing device similar to the one in this study may be useful in the future for conducting preliminary studies of new or established tension-band techniques. The proposed tension-band suture method tested in this dissertation provided statistically significant quantitative data, which may after further work, support its use as an alternative method in the clinical setting.