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An assessment of postnatal growth after in utero long bone osteotomy with fixation
J A Goldstein1, J C Posnick, M D Wells
1Department of Surgery, Hospital for Sick Children, Toronto, Ontario, Canada.
Insights
Rigid fixation of fetal bone fractures using miniplates did not impede postnatal growth in sheep. Post-mortem analysis showed normal bone development and no significant differences in limb measurements between operated and control limbs.
Area of Science:
- Orthopedic surgery
- Developmental biology
- Animal models
Background:
- Rigid fixation of immature bones may hinder skeletal development.
- Understanding the impact of in utero interventions is crucial for pediatric orthopedics.
Purpose of the Study:
- To evaluate the effect of in utero tibial osteotomy with miniplate fixation on postnatal growth in fetal sheep.
- To assess bone morphology, radiography, and histology after fetal bone surgery.
Main Methods:
- Midshaft tibial osteotomy performed on fetal sheep (n=5) at 95 days' gestation.
- Fixation with a titanium miniplate and screws; contralateral limb as control.
- Postnatal assessment at 2 months, including gross morphology, radiography, and histology.
Main Results:
- No gross morphologic differences or visible osteotomy sites radiographically.
- No statistically significant differences in tibia, femur, or metatarsal bone measurements.
- Histology confirmed bone incorporation, appositional growth, and normal lamellar bone structure.
Conclusions:
- In utero tibial osteotomy with rigid miniplate fixation does not adversely affect postnatal skeletal growth in sheep.
- The immature ovine skeleton demonstrates robust healing and growth potential following surgical intervention.
Abstract:
Researchers have recently suggested that rigid fixation of the immature bony skeleton may restrict growth and development. This study assesses the effect on postnatal growth of an in utero tibial osteotomy fixed with a miniplate in fetal sheep. A midshaft osteotomy was performed on fetal sheep tibia (n = 5) at 95 days' gestation (term 145 days). One tibia was reduced and fixed with a titanium miniplate and screws, while the contralateral hindlimb served as a control. The newborns were vaginally delivered and sacrificed at 2 months of age. The hindlimbs, control and fractured, were harvested, stripped of soft tissue, and the tibia, femur, and distal metatarsal were each measured and weighed. Each tibia also underwent radiographic analysis and histologic examination (after decalcification) using hematoxylin and eosin, Sirius red, and Alcian blue stains. No prenatal, postnatal, or perioperative medical complications occurred. Apart from a slight angulation in one operated tibia, no gross morphologic differences, either visible or palpable, were found between the operated and control limbs. This was confirmed radiographically where no remnant of the osteotomy site was visible. Measurements of the operated and control tibias, femurs, and metatarsal bones were not statistically different. Histologic analysis showed a total incorporation of bone at the osteotomy site with appositional growth present. All bone was lamellar with longitudinal orientation. In the area of the screw sites, the surrounding bone shaft was the same width as its neighboring bone.(ABSTRACT TRUNCATED AT 250 WORDS)