title: Biomechanical testing of a concept of posterior pelvic reconstruction in rotationally and vertically unstable fractures.
abstract: The purpose of this study was to assess the stability of a developmental pelvic reconstruction system which extends the concept of triangular osteosynthesis with fixation anterior to the lumbosacral pivot point. An unstable Tile type-C fracture, associated with a sacral transforaminal fracture, was created in synthetic pelves. The new concept was compared with three other constructs, including bilateral iliosacral screws, a tension band plate and a combined plate with screws. The pubic symphysis was plated in all cases. The pelvic ring was loaded to simulate single-stance posture in a cyclical manner until failure, defined as a displacement of 2 mm or 2°. The screws were the weakest construct, failing with a load of 50 N after 400 cycles, with maximal translation in the craniocaudal axis of 12 mm. A tension band plate resisted greater load but failure occurred at 100 N, with maximal rotational displacement around the mediolateral axis of 2.3°. The combination of a plate and screws led to an improvement in stability at the 100 N load level, but rotational failure still occurred around the mediolateral axis. The pelvic reconstruction system was the most stable construct, with a maximal displacement of 2.1° of rotation around the mediolateral axis at a load of 500 N.
authors.affiliation: St George's Hospital, Blackshaw Road, Tooting, London SW17 0QT, UK. onurberber@yahoo.co.uk
authors.forename: O
authors.initials: O
authors.lastname: Berber
authors.forename: A A
authors.initials: AA
authors.lastname: Amis
authors.forename: A C
authors.initials: AC
authors.lastname: Day
mesh_terms: D001860:Bone Plates; D001863:Bone Screws; D005593:Fracture Fixation, Internal / Q000295:instrumentation / Q000379:methods*; D050723:Fractures, Bone / Q000601:surgery*; D006801:Humans; D007085:Ilium / Q000503:physiopathology; D008422:Materials Testing / Q000379:methods; D008953:Models, Anatomic; D010384:Pelvic Bones / Q000293:injuries* / Q000601:surgery*; D012399:Rotation; D012447:Sacrum / Q000503:physiopathology; D013314:Stress, Mechanical