Changes of osteocalcin and IGF-I during bone lengthening

Objective: To examine the changes of osteocalcin and insulin-like growth factor I (IGF-I) during bone lengthening, and to clarify the mechanism of bone healing. Methods: Thirty-two shepherd dogs were divided into five groups randomly. Their tibiae were lengthened by Ilvzarov’s external fixator at the rate of 1 mm/day. The lengthening area was the experimental side and the opposite side was the control. Samples were obtained on the 2nd, 4th, 6th, 8th, 12th weekend respectively. The samples were defatted, dried, powdered, centrifuged and measured by radioimmunoassay. Results: The osteocalcin concentration increased at the subsequent periods, but it was significantly lower in the experimental side than that of the control side, P<(0.05) and the IGF-I concentration was not significantly lowered. Conclusions: Different noncollagenous bone growth factors may be different at different stage.

International recognition of the Ilizarov bone reconstruction techniques: Current practice and research (dedicated to 100th birthday of G. A. Ilizarov)

The Ilizarov method is one of the current methods used in bone reconstruction.It originated in the middle of the past century and comprises a number of bone reconstruction techniques executed with a ring external fixator developed by Ilizarov GA.Its main merits are viable new bone formation through distraction osteogenesis,high union rates and functional use of the limb throughout the course of treatment.The study of the phenomenon of distraction osteogenesis induced by tension stress with the Ilizarov apparatus was the impetus for advancement in bone reconstruction surgery.Since then,the original method has been used along with a number of its modifications developed due to emergence of new fixation devices and techniques of their application such as hexapod external fixators and motorized intramedullary lengthening nails.They gave rise to a relatively new orthopedic subspecialty termed“limb lengthening and reconstruction surgery”.Based on a comprehensive literature search,we summarized the recent clinical practice and research in bone reconstruction by the Ilizarov method with a special focus on its modification and recognition by the world orthopedic community.The international influence of the Ilizarov method was reviewed in regard to the origin country of the authors and journal’s rating.The Ilizarov method and other techniques based on distraction osteogenesis have been used in many countries and on all populated continents.It proves its international significance and confirms the greatest contribution of Ilizarov GA to bone reconstruction surgery.

Treatment of tibial defect and bone nonunion with limb shortening with external fixator and reconstituted bone xenograft

Objective: To explore the effect of external fixator and reconstituted bone xenograft (RBX) in the treatment of tibial bone defect, tibial bone nonunion and congenital pseudarthrosis of the tibia with limb shortening. Methods: Twenty patients ( 13 males and 7 females) with tibial bone defect, tibial bone nonunion or congenital pseudarthrosis of the tibia with limb shortening were treated with external fixation. Two kinds of external fixators were used: a half ring sulcated external fixator used in 13 patients and a combined external fixator in 7 patients. Foot-drop was corrected at the same time with external fixation in 4 patients. The shortened length of the tibia was in the range of 2-9 cm, with an average of 4.8 cm. For bone grafting, RBX was used in 12 patients, autogenous ilium was used in 3 patients and autogenous fibula was implanted as a bone plug into the medullary canal in 1 case, and no bone graft was used in 4 patients. Results: All the 20 patients were followed-up for 8 months to 7 years, averaging 51 months. Satisfactory function of the affected extremities was obtained. All the shortened extremities were lengthened to the expected length. For all the lengthening area and the fracture sites, bone union was obtained at the last. The average healing time of 12 patients treated with RBX was 4.8 months. Conclusions: Both the half ring sulcated external fixator and the combined external fixator have the advantages of small trauma, simple operation, elastic fixation without stress shielding and non-limitation from local soft tissue conditions, and there is satisfactory functional recovery of affected extremities in the treatment of tibial bone defects, tibial bone nonunion and congenital pseudarthrosis of the tibia combined with limb shortening. RBX has good biocompatibility and does not cause immunological rejections. It can also be safely used in treatment of bone nonunion and has reliable effect to promote bone healing.

Component changes of calcium and phosphorus in osteogenesis by lengthening procedures in adult canines

Objective: To explore chemical component changes of dog bone at different lengthening time and in different bone regions of interest, and to evaluate the mineralization during Ilizarov lengthening process. Methods: The ash weight, the concentrations of calcium, phosphorus and the calcium/phosphorus ratio were measured at different intervals (2, 4, 6, 8, 12 weeks) since lengthening and the lengthened part was compared with a control area at each interval. Results: The ash weight, the concentrations of calcium and phosphorus in the lengthened area differed at all development time. The calcium/phosphorus (Ca/P) ratio in the lengthened region remained significantly lower than that in the control region up to 12 weeks after the lengthening. Conclusions: These results suggest that also other inorganic ions play an important role in the mineralization process and that they become relatively more important since 8 weeks after the lengthening.