Effects of graded reaming on fracture healing. Blood flow and healing studied in rat femurs.
In 30 rats, closed bilateral fractures of the femur were produced. On the left side intramedullary reaming was performed to 1.6 mm, and the fracture fixed-with a steel pin with a diameter of 1.6 mm. On the right side the femoral canal was reamed to 2.0 mm and a hollow steel tube with a diameter of 2.0 mm was used for fixation. An additional 8 rats were used to obtain mechanical, dimensional and flow data on intact femurs, and another 10 rats were used to study the acute flow changes caused by fracture and different degrees of reaming and fracture. Fracture and reaming reduced total bone and cortical bone blood flows to about one third of normal flow, with no differences between the 1.6-mm and the 2.0-mm reamed bones. At 4 weeks, total bone flow was about double and cortical bone flow about 4 times increased in the 1.6-mm group. In the 2.0-mm reamed bones increases of approximately 5 times in total bone flow and of about 7 times in cortical flow were found. Callus flow was about twice the size of the respective cortical flow in both groups. Both total and cortical flows gradually subsided, without differences between the 2 groups. At 12 weeks, the callus area in the 2.0-mm group was greater than in the 1.6-mm group, while bone dimensions were greater in the 2.0-mm group at 4 and 12 weeks. Bending moment and rigidity were greater in the 1.6-mm group than in the 2.0-mm one at every time interval; no differences were found in fracture energy.(ABSTRACT TRUNCATED AT 250 WORDS)
Grundnes
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Department of Orthopedics, University Hospital, Tromsø, Norway.
Utvåg
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SE
Reikerås
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O
D000818:Animals; D001696:Biomechanical Phenomena; D001858:Bone Nails; D002146:Bony Callus / Q000098:blood supply / Q000502:physiology*; D005264:Femoral Fractures / Q000503:physiopathology* / Q000601:surgery; D005269:Femur / Q000098:blood supply; D005594:Fracture Fixation, Intramedullary; D017102:Fracture Healing / Q000502:physiology*; D005596:Fractures, Closed / Q000503:physiopathology* / Q000601:surgery; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012039:Regional Blood Flow / Q000502:physiology*; D013997:Time Factors