title: [The AO/ASIF Flexnail : A flexible intramedullary nail for the treatment of humeral shaft fractures].
abstract: BACKGROUND
  The use of conventional implants for intramedullary nailing of humeral shaft fractures is associated with specific difficulties. During antegrade implantation structures of the rotator cuff can be affected leading to a reduced functional result of the shoulder. If the nail is implanted in a retrograde manner problems arise due to a relatively large hole close to or within the olecranon fossa, which is necessary for insertion of the nail. Supracondylar fractures as well as persistent elbow pain and loss of function are reported in the literature. To overcome these disadvantages a flexible nail has been developed that can be stiffened and locked after implantation.
  
  
  METHODS
  Between October 2000 and February 2002, 34 patients were treated with the flexible nail at our institution; 29 were available for follow-up. Fracture healing was documented on radiographs and clinical outcome was evaluated with use of the Constant as well as the Kwasny score.
  
  
  RESULTS
  Median duration until fracture consolidation was 10 weeks. In two patients fracture union was not achieved within the follow-up period. The median outcome measured with the Constant score was 93 points and 2.5 with the Kwasny score. Both values correspond to a very good functional outcome.
  
  
  CONCLUSIONS
  We conclude that the flexible humeral nail is an excellent treatment option for humeral shaft fractures. Damage to the rotator cuff and the distal humerus can be avoided due to its unique flexible construction, improving the functional outcome of intramedullary nailing for the treatment of humeral shaft fractures.
authors.affiliation: Klinik für Unfall-, Hand- und orthopädische Chirurgie, Klinikum Karlsruhe, Moltkestrasse 90, 76133 Karlsruhe, Germany. christof.mueller@Klinikum-Karlsruhe.com
authors.forename: C A
authors.initials: CA
authors.lastname: Müller
authors.forename: P
authors.initials: P
authors.lastname: Henle
authors.forename: G
authors.initials: G
authors.lastname: Konrad
authors.forename: M
authors.initials: M
authors.lastname: Szarzynski
authors.forename: P C
authors.initials: PC
authors.lastname: Strohm
authors.forename: N P
authors.initials: NP
authors.lastname: Südkamp
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001858:Bone Nails; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D005594:Fracture Fixation, Intramedullary / Q000295:instrumentation*; D017102:Fracture Healing / Q000502:physiology; D006801:Humans; D006810:Humeral Fractures / Q000145:classification / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D018583:Pliability; D011183:Postoperative Complications / Q000000981:diagnostic imaging; D011859:Radiography