title: Biomechanical comparison of different pin configurations during percutaneous pinning for the treatment of proximal humeral fractures.
abstract: We investigate the influence on fracture stability of different pin configurations during percutaneous pinning for the treatment of proximal humeral fractures. We performed a matched-paired study of 18 pairs of adult fresh-frozen humeri (36 humeri), which were divided into 4 groups. A 2-part surgical neck fracture model was used in all humeri, and 4 terminal threaded pins (2.5 mm in diameter) were used for fixation. Parallel-type pinning (box type) was carried out in 2 groups, and convergent-type pinning (fan-shaped type) was used in the other 2 groups. For each specimen, both anti-shear ultimate load and anti-torsion ultimate load were measured. There was no statistical difference between the parallel pin construct and convergent construct with regard to anti-shear resistance (P = .73). However, the parallel pin construct had a significant advantage over the convergent construct regarding anti-torsion resistance. The parallel pin construct has better torsional stability when 1 cm is used for the pin-to-pin distance. We suggest that parallel pin fixation should be applied whenever possible.
authors.affiliation: School of Medicine, Peking University, Beijing, China. chunyanj@hotmail.com
authors.forename: Chunyan
authors.initials: C
authors.lastname: Jiang
authors.forename: Yiming
authors.initials: Y
authors.lastname: Zhu
authors.forename: Manyi
authors.initials: M
authors.lastname: Wang
authors.forename: Guowei
authors.initials: G
authors.lastname: Rong
mesh_terms: D001696:Biomechanical Phenomena; D001858:Bone Nails; D002102:Cadaver; D005592:Fracture Fixation; D006801:Humans; D011474:Prosthesis Design; D012784:Shoulder Fractures / Q000601:surgery*