title: Femur flap for tibial reconstruction: percent circumference required to convey a mechanical advantage over the fibula.
abstract: The fibula flap is commonly used to reconstruct the tibia. This has risk of postoperative fracture despite long-term non-weight bearing. A flap using noncircumferential distal femur is proposed. This study is to determine the circumference of femur required to produce greater strength than the fibular flap. Femurs and fibulas were harvested from eight cadavers. The structural strength of fibula and femur flaps was assessed using three-point bend. Compression testing was performed on osteotomized and whole femurs to assess donor site morbidity. The 35% flap (mean maximum force at fracture 869 N) was not significantly stronger than the fibula flap (626 N; P > 0.05). The 40% flap (1225 N) was significantly stronger than the fibula flap ( P < 0.01). There was no significant difference between forces at fracture for whole femurs (3978 N), femurs with 35% osteotomies (3604 N), and femurs with 40% osteotomies (3493 N; P = 0.87). Change occurred in the fracture pattern of femurs following osteotomies. Whole femurs consistently fractured at the femoral neck, and osteotomized femurs consistently fractured obliquely from the osteotomy. A flap consisting of 40% of the circumference of the distal femur exceeds the structural strength of the fibular flap. Taking such a flap changes the femur's structural integrity; fixation may be prudent following harvest.
authors.affiliation: Department of Surgery, Division of Plastic and Reconstructive Surgery, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA. broderick@umassmemorial.org
authors.forename: Genevieve
authors.initials: G
authors.lastname: Broderick
authors.forename: Janice
authors.initials: J
authors.lastname: Lalikos
authors.forename: Matthew
authors.initials: M
authors.lastname: Chowaniec
authors.forename: Meghan
authors.initials: M
authors.lastname: Collins
authors.forename: Elias
authors.initials: E
authors.lastname: Wilson
authors.forename: Russell
authors.initials: R
authors.lastname: Babbitt
authors.forename: Julie
authors.initials: J
authors.lastname: O'Brien
authors.forename: Kristen
authors.initials: K
authors.lastname: Billiar
authors.forename: Raymond M
authors.initials: RM
authors.lastname: Dunn
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D002102:Cadaver; D005269:Femur / Q000637:transplantation*; D005360:Fibula / Q000637:transplantation*; D006801:Humans; D010027:Osteotomy / Q000379:methods; D013314:Stress, Mechanical; D013524:Surgical Flaps; D013977:Tibia / Q000601:surgery*