[Experimental studies of segmental bone defects treated by skeletal external fixation].
Bony tissue of an average of 13.6% of the original length (OL) was resected from the tibia shaft in 26 mature goats. The fracture ends were compressively fixed with skeletal external fixation (SEF). Simultaneously, upper metaphysiotomy was performed to lengthen the tibia with a lengthening rate of 1.0 mm/d and a total lengthening 20.14% of OL. The restoration of blood circulation and the hemodynamic changes during the repair process of the compressively fixed bone ends and the metaphysiotomy site were studied with angiography, microvascular cast, Chinese ink permeated transparent thick slide, and radioactive microsphere measurement of regional blood flow (RBF). It was found that there were abundant vascular networks in the lengthened zone. The blood vessels not only could keep up with the same lengthening rate of growing, but also were gradually converted into the Haversian system in the newly formed cortex of the lengthened area. In the 2nd week after the cessation of bone lengthening, the RBF of the lengthened zone reached the maximum (54.56 +/- 8.53 ml/mm/100 g). It was also found that in the 7th postoperative week, the vessels of the cortex of the osteotomy shortening ends could grow across the space between them and anastomose with each other. The RBF at this time was 31.82 +/- 2.85 ml/mm/100 g. In the 12th week after operation, the RBF was still 2 times higher than that of the normal cortex (3.02 +/- 0.13 ml/mm/100 g). The primary healing could be observed under the wellreduction and stable compressive external fixation. These findings provide a theoretical basis for the clinical application of SEF for the treatment of tibial shaft defects or nonunion associated with limb shortening.
Yang
L
L
Department of Orthopaedics, Southwest Hospital, Third Military Medical College, Chongqing.
Li
Q
Q
Zhou
Z
Z
D000818:Animals; D001852:Bone Lengthening; D005260:Female; D005592:Fracture Fixation; D017102:Fracture Healing; D006041:Goats; D008297:Male; D008833:Microcirculation; D008855:Microscopy, Electron, Scanning; D013977:Tibia / Q000098:blood supply / Q000648:ultrastructure; D013978:Tibial Fractures / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*