ABSTRACT
Objective To evalute the effect of Ilizarov technique in the treatment of hypertrophic nonunion.Methods Form June 2008 to December 2010,12 patients with hypertrophic nonunion were treated with Ilizarov technique,including 10 males and 2 females with an average age of 46.5 years.The pathology sites of nonunion were kept as closed as possible without any bone graft during operation.As to patients who had ever been treated with plate or intramedullary nail,the hardware should be removed by minimal invasive approach.These procedures aimed to keep the vascularity of nonunion site intact.Ilizarov apparatus were preoperatively constructed.Distal segment and proximal segment of nonunion were mounted respectively with two external circle using the smooth wires and half pins.The two-circle stabilizing one segment was nominated with transosseous modules.Distal module and proximal one was connected with a pair of axial hinges.The pathology sites were gradually distracted from the seventh day postoperatively,0.25 mm/d.Accompanying with deformity correction,limb length discrepancy (LLD) also were restored simultaneously.Then,all the screws and nuts in the apparatus should be tightened,which was favourable to the callus consolidation.Results All 12 cases of nonunion healed without any bone graft.The fixator wearing time lasted 6-12 months,with an average of 8 months.Correction of deformity and LLD were achieved.The average lengthening was 3.0 cm (range,2.0-5.5 cm),the average correction angle was 23° (range,10°-30°).After 6-18 months follow-up,all the patients restored satisfactory function.Conclusion Hypertrophic nonunion can be treated successfully with Ilizarov technique.The key of successful callus distraction is strictly identifying the indications.
ABSTRACT
Objective To investigate the influence of low frequency micromovement induced by an external fixator with controlled micromovement device on callus formation and fracture healing. Methods 39 sheep were involved in the study. After transverse osteotomy with a gap of 2 mm was done at the mid-shaft of both tibias, the hind limbs were fixed with unilateral external fixators with controlled micromovement device. 10 days after osteotomy, one hind limb of the sheep was randomly selected to have micromovement. According to different micromovement frequencies, the sheep were randomly divided into 3 groups: Group A, 0.5 Hertz; Group B, 1 Hertz; Group C, 5 Hertz. The micromovement had an amplitude of 0.25mm and stopped by the end of the fourth postoperative week (30 min/d). The other hind limb of each sheep did not have micromovement and served as the control. Macrostructural and histological observations, radiographic examinations, and biomechanical tests were done respectively at 4, 6, 9 weeks after osteotomy. Results Macrostructural observations and X-ray examinations revealed a large amount of callus formation with a peak at the end of the fourth postoperative week in the 3 experimental groups. Histological analysis showed faster endochondral ossification and osteoid formation in the experimental groups than in the control by the sixth postoperative week, with the highest rate in Group B (1Hz). Biomechanical tests proved that the bending stiffness in the experimental groups was superior to that in the control, with the strongest in Group B (1 Hz). Conclusions Low frequency-micromovement at the fracture sites can promote callus formation and accelerate mineralization at the early stage of fracture healing. A frequency of 1 Hz can produce the best results.