title: The role of lesser trochanter fragment in unstable pertrochanteric A2 proximal femur fractures - is refixation of the lesser trochanter worth the effort?
abstract: BACKGROUND
  Instability of osteoporotic pertrochanteric fractures is defined by loss of medial/lateral cortical integrity with the posteromedial fragment including the lesser trochanter being pivotal for load distribution. Literature addressing the importance of lesser trochanter refixation is scarce. To clarify the effect of lesser trochanter refixation on primary stability in these fractures, following study was performed.
  
  
  METHODS
  21 femora were match-paired in 3 groups and osteotomized, creating pertrochanteric fractures (AO-31A2). Group 1 was stabilized with a proximal femoral nail, group 2 with a dynamic hip screw and group 3 with an augmented proximal femoral nail. Each femur was tested non-destructively at 200 and 400N with and without refixation of the lesser trochanter (configuration A/B). The overall stiffness and movement of the femoral neck was recorded.
  
  
  RESULTS
  At 200N, refixation reduced movement of the femoral neck and increased overall stiffness significantly in group 1 and 3. At 400N, refixation decreased movement of the femoral neck not significantly in all groups (1=38%, 2=36%, 3=43%). The augmented proximal femoral nail after refixation showed the highest stability of all constructs.
  
  
  CONCLUSIONS
  Refixation of the lesser trochanter may increase the primary stability of pertrochanteric fracture osteosynthesis as all groups showed a higher primary stability. Therefore, refixation should be considered in unstable, osteoporotic fractures. If additional trauma through refixation appears inappropriate, cement augmentation should be performed as it showed only 9% less stability than a non-augmented proximal femoral nail with refixation of the lesser trochanter.
authors.affiliation: Department of Traumatology, Hand, Plastic, and Reconstructive Surgery, Center of Surgery, Ulm University, Albert-Einstein-Allee 23, 89081 Ulm, Germany. Electronic address: ehrnthaller@gmx.net.
authors.forename: Christian
authors.initials: C
authors.lastname: Ehrnthaller
authors.affiliation: Department of Traumatology, Hand, Plastic, and Reconstructive Surgery, Center of Surgery, Ulm University, Albert-Einstein-Allee 23, 89081 Ulm, Germany.
authors.forename: Alain Christoph
authors.initials: AC
authors.lastname: Olivier
authors.affiliation: Department of Traumatology, Hand, Plastic, and Reconstructive Surgery, Center of Surgery, Ulm University, Albert-Einstein-Allee 23, 89081 Ulm, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Gebhard
authors.affiliation: Institute of Orthopaedic Research and Biomechanics, Center for Trauma Research Ulm, Ulm University, Helmholtzstraße 14, 89081 Ulm, Germany.
authors.forename: Lutz
authors.initials: L
authors.lastname: Dürselen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D001858:Bone Nails; D001863:Bone Screws; D005260:Female; D005264:Femoral Fractures / Q000503:physiopathology / Q000601:surgery*; D005269:Femur / Q000502:physiology*; D005272:Femur Neck / Q000503:physiopathology; D005593:Fracture Fixation, Internal / Q000379:methods*; D006621:Hip Joint / Q000503:physiopathology; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D058866:Osteoporotic Fractures / Q000503:physiopathology / Q000601:surgery*; D012086:Reoperation
keywords: Cement augmentation; DHS; PFNA; Refixation lesser trochanter; Stability