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Effect of varus and valgus alignment on implant loading after proximal femur fracture fixation

  • Meir Marmor
  • Kate Liddle
  • Jenni Buckley
  • Amir MatityahuEmail author
Original Article • HIP - FRACTURES

Abstract

Introduction

More than 10 % of proximal femur fractures repaired with either a sliding hip screw and side plate (SHS-P) or a sliding hip screw and intramedullary nail (SHS-IMN) demonstrate varus malreduction. The purpose of this study was to compare the effect of varus or valgus loading on comminuted intertrochanteric fractures repaired with SHS-P or SHS-IMN constructs.

Methods

Unstable intertrochanteric fractures with segmental comminution were generated in 12 cadaver proximal femurs, six of which were fixed with an SHS-P and six with an SHS-IMN. Both implants had a strain gauge at the lag screw-nail–plate interface to assess implant load bearing. The load on the implants was measured with the specimens in neutral position and at 5°, 10°, and 15° of varus and valgus.

Results

Loads on both SHS-IMN and SHS-P constructs were significantly increased when loading the implants in varus and significantly decreased when loading the implants in valgus. Unlike the SHS-IMN, the SHS-P trended toward increased load bearing at 15° varus (159.1 vs. 118.5 %, P = .065) and trended toward less load bearing at 15° valgus (42.3 vs. 59.8 %, P = .06). Conclusions: Regardless of implant choice, avoiding varus loading on the fixation construct reduces the load on the implant. SHS-P constructs may be more affected by varus or valgus malalignment than SHS-IMN constructs.

Keywords

Proximal femur fracture Varus Malreduction Fracture fixation Intramedullary nailing Hip fracture Intertrochanteric fracture Pertrochanteric fracture Biomechanical testing 

Notes

Funding

This study was partially funded by a RAP grant for young investigators from UCSF. No grant number is associated with this study.

Compliance with ethical standards

Conflict of interest

This study was funded by a grant from the UCSF Resource Allocation Program (RAP). None of the authors have conflicts of interest relevant to this study.

Ethical approval

This article does not contain any studies with human participants or animals performed by any of the authors.

References

  1. 1.
    Lindskog DM, Baumgaertner MR (2004) Unstable intertrochanteric hip fractures in the elderly. J Am Acad Orthop Surg 12:179–190CrossRefPubMedGoogle Scholar
  2. 2.
    Bucholz RW, Heckman JD, Court-Brown CM, Tornetta P (2010) Intertrochanteric fractures of the hip. In: Court-Brown C, Heckman JD, McKee M, McQueen MM, Ricci W, Tornetta III P (eds) Rockwood and green’s fractures in adults, 7th Edn. Lippincott Williams & Wilkins, pp 1597–1640Google Scholar
  3. 3.
    Madsen JE, Nass L, Aune AK, Alho A, Ekeland A, Stromsoe K (1998) Dynamic hip screw with trochanteric stabilizing plate in the treatment of unstable proximal femoral fractures: a comparative study with the gamma nail and compression hip screw. J Orthop Trauma 12:241–248CrossRefPubMedGoogle Scholar
  4. 4.
    Simmermacher RKJ, Ljungqvist J, Bail H et al (2008) The new proximal femoral nail antirotation (PFNA) in daily practice: results of a multicentre clinical study. Injury 39:932–993CrossRefPubMedGoogle Scholar
  5. 5.
    Laros GS, Moore JF (1974) Complications of fixation in intertrochanteric fractures. Clin Orthop Relat Res 101:110–119PubMedGoogle Scholar
  6. 6.
    Schipper IB, Marti RK, Van Der Werken C (2004) Unstable trochanteric femoral fractures: extramedullary or intramedullary fixation: review of literature. Injury 35:142–151CrossRefPubMedGoogle Scholar
  7. 7.
    Baumgaertner MR, Curtin SL, Lindskog DM, Keggi JM (1995) The value of the tip-apex distance in predicting failure of fixation of peritrochanteric fractures of the hip. J Bone Jt Surg Am 77:1058–1064Google Scholar
  8. 8.
    Ruecker AH, Rupprecht M, Gruber M, Gebauer M, Barvencik F, Briem D, Rueger JM (2009) The treatment of intertrochanteric fractures: results using an intramedullary nail with integrated cephalocervical screws and linear compression. J Orthop Trauma 23(1):22–30CrossRefPubMedGoogle Scholar
  9. 9.
    Utrilla AL, Reig JS, Muñoz FM, Tufanisco CB (2005) Trochanteric gamma nail and compression hip screw for trochanteric fractures: a randomized, prospective, comparative study in 210 elderly patients with a new design of the gamma nail. J Orthop Trauma 19:229–233CrossRefPubMedGoogle Scholar
  10. 10.
    Barton TM, Gleeson R, Topliss C, Greenwood R, Harries WJ, Chesser TJS (2010) A comparison of the long gamma nail with the sliding hip screw for the treatment of AO/OTA 31-A2 fractures of the proximal part of the femur: a prospective randomized trial. J Bone Jt Surg Am 92(4):792–798CrossRefGoogle Scholar
  11. 11.
    Jin WJ, Dai LY, Cui YM, Zhou Q, Jiang LS, Lu H (2005) Reliability of classification systems for intertrochanteric fractures of the proximal femur in experienced orthopaedic surgeons. Injury 36(7):858–861CrossRefPubMedGoogle Scholar
  12. 12.
    Saudan M, Lübbeke A, Sadowski C, Riand N, Stern R, Hoffmeyer P (2002) Petrochanteric fractures: Is there an advantage to an intramedullary nail? A randomized, prospective study of 206 patients comparing the dynamic hip screw and proximal femoral nail. J Orthop Trauma 16(6):386–393CrossRefPubMedGoogle Scholar
  13. 13.
    Stern R (2007) Are there advances in the treatment of extracapsular hip fractures in the elderly? Injury 38(3):S77–S87CrossRefPubMedGoogle Scholar
  14. 14.
    Baumgaertner MR, Oetgen ME (2009) Chapter 9: Intertrochanteric hip fractures. Skeletal trauma: basic science, management and reconstruction, 4th edn. Elsevier, Philadelphia, pp 1913–1956CrossRefGoogle Scholar
  15. 15.
    Cummings SR, Rubin SM, Black D (1990) The future of hip fractures in the United States: numbers, costs, and potential effects of postmenopausal estrogen. Clin Orthop 252:163–166PubMedGoogle Scholar
  16. 16.
    Koval KJ, Aharonoff GB, Rokito AS, Lyon T, Zuckerman JD (1996) Patients with femoral neck and intertrochanteric fractures. Are they the same? Clin Orthop Relat Res 330:166–172CrossRefPubMedGoogle Scholar
  17. 17.
    Tia et al (2008) A novel technique for measuring pedicle screw forces in situ. Presented at ASME summer Bioengineering conference, Marco Islands, FloridaGoogle Scholar
  18. 18.
    Eberle S, Bauer C, Gerber C et al (2010) The stability of a hip fracture determines the fatigue of an intramedullary nail. Proc Inst Mech Eng H 224:577–584CrossRefPubMedGoogle Scholar
  19. 19.
    Bay BK, Hamel AJ, Olson SA et al (1997) Statically equivalent load and support conditions produce different hip joint contact pressures and periacetabular strains. J Biomech 30:193–196CrossRefPubMedGoogle Scholar
  20. 20.
    Haidukewych GJ, Israel TA, Berry DJ (2001) Reverse obliquity fractures of the intertrochanteric region of the femur. J Bone Joint Surg Am 83:643–650PubMedGoogle Scholar
  21. 21.
    Marmor M, Liddle K, Pekmezci M, Buckley J, Matityahu A (2013) The effect of fracture pattern stability and post-reduction alignment on implant loading in OTA type 31-A2 proximal femur fractures. J Orthop Trauma 27(12):683–689CrossRefPubMedGoogle Scholar
  22. 22.
    Parker MJ, Handoll HH (2008) Gamma and other cephalocondylic intramedullary nails versus extramedullary implants for extracapsular hip fractures in adults. Cochrane Database Syst Rev 16(3):CD000093Google Scholar
  23. 23.
    Leung KS, So WS, Shen WY, Hui PW (1992) Gamma nails and dynamic hip screws for peritrochanteric fractures. A randomised prospective study in elderly patients. J Bone Jt Surg Br 74(3):345–351Google Scholar
  24. 24.
    O’Brien PJ, Meek RN, Blachut PA, Broekhuyse HM, Sabharwal S (1995) Fixation of intertrochanteric hip fractures: gamma nail versus dynamic hip screw. A randomised, prospective study. Can J Surg 38(6):516–520PubMedGoogle Scholar
  25. 25.
    Park SR, Kang JS, Kim HS, Lee WH (1998) Treatment of intertrochanteric fracture with the gamma AP locking nail or by a compression hip screw—a randomised prospective trial. Int Orthop 22(3):157–160CrossRefPubMedPubMedCentralGoogle Scholar
  26. 26.
    Ahrengart L, Tornkvist H, Fornander P, Thorngren KG, Pasanen L, Wahlstrom P et al (2002) A randomized study of the compression hip screw and gamma nail in 426 fractures. Clin Orthop Relat Res 401:209–222CrossRefPubMedGoogle Scholar
  27. 27.
    Rosenblum SF, Zuckerman JD, Kummer FJ, Tam BS (1992) A biomechanical evaluation of the gamma nail. J Bone Jt Surg Br 74(3):352–357Google Scholar

Copyright information

© Springer-Verlag France 2016

Authors and Affiliations

  1. 1.Orthopaedic Trauma Institute, San Francisco General HospitalUniversity of California, San FranciscoSan FranciscoUSA
  2. 2.UCSF School of MedicineSan FranciscoUSA
  3. 3.Department of Mechanical EngineeringUniversity of DelawareNewarkUSA

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