title: Biomechanical in vitro assessment of fixed angle plating using a new concept of locking for the treatment of osteoporotic proximal humerus fractures.
abstract: Locked plating attempts to improve mechanical stability via better anchorage of the screws in the bone. In 22 paired osteoporotic humeri an AO/ASIF 11-B 1 fracture was created. Locked and conventional plating using the same device of the latest generation was performed. Torsional loading around three axes (x = varus/valgus, y = flexion/extension, z = axial rotation) with an increasing moment (2, 3.5, 5 and 7.5 N·m) was applied. Interfragmentary motion within the locked group was lower for all three axes with higher cumulative survival rates (p < 0.05). The typical mode of failure was loss of fixation in the humeral head occurring earlier in the conventional group. The locking mechanism investigated provides more ultimate strength in an osteoporotic proximal humerus fracture model. Correlation with BMD suggests that this device may especially be suitable for use in osteoporotic bone.
authors.affiliation: Department of Orthopaedic Trauma, Ulm University, Ulm, Germany. goetz.roederer@uniklinik-ulm.de
authors.forename: Götz
authors.initials: G
authors.lastname: Röderer
authors.forename: Florian
authors.initials: F
authors.lastname: Gebhard
authors.forename: Gert
authors.initials: G
authors.lastname: Krischak
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Wilke
authors.forename: Lutz
authors.initials: L
authors.lastname: Claes
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D001860:Bone Plates; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis; D058866:Osteoporotic Fractures / Q000503:physiopathology / Q000601:surgery*; D010027:Osteotomy; D011475:Prosthesis Failure; D012784:Shoulder Fractures / Q000503:physiopathology / Q000601:surgery*; D013314:Stress, Mechanical; D016474:Weight-Bearing