Sliding Hip Screw / Dynamic Hip Screw

Paul Duffy, M.D., FRCSC
Calgary, AB

Intertrochanteric fractures in the elderly are very common and result in significant morbidity and mortality. Operative management has become the standard of care for these fractures since the late 1940s and controversy over the choice of implant for the management of intertrochanteric hip fractures continues. Across Canada and, indeed, the world we debate the use of the sliding hip screw versus intramedullary fixation for the treatment of intertrochanteric hip fractures.

 

History
The fixation of extracapsular hip fractures was first introduced in the 1950s using a variety of implants. Static implants such as the Jewett and McLaughlin nail plates gave way to a variety of sliding hip screws such as the Dynamic, Richards and Ambi Hip screws. For over 30 years hundreds of thousands of intertrochanteric hip fractures worldwide were treated using these techniques and implants. In the late 1980s we saw the introduction of intramedullary nails for the treatment of extracapsular fractures. The Gamma nail was introduced in the late 1980s and has undergone numerous design changes. Since the introduction of the Gamma nail, there have been the intramedullary hip screw (IMHS), the proximal femoral nail (PFN) and other variations of intramedullary devices based on the same theme.

Trends
Despite no concrete evidence of improvement in patient care or functional outcomes, there has been a dramatic increase in the use of intramedullary fixation for the treatment of intertrochanteric hip fractures. Anglen reviewed the American Board of Orthopedic Surgery database where candidates submit a six-month surgical case list and patient data in preparation for their national certification exam1. That data demonstrated a drastic change in practice patterns among young surgeons with intramedullary nail fixation increasing from 3% in 1999 to 67% in 2006 for the treatment of intertrochanteric hip fractures. Anglen states "this change has occurred despite a lack of evidence in the literature supporting the change and in the face of the potential for more complication."

duffy1
Figure 1: Early postoperative fracture associated with the short Gamma Nail.

Evidence
There is no shortage of literature comparing these two fixation techniques1,2,3,4,5,6. Proponents of intramedullary fixation suggest numerous advantages of nailing including minimally invasive surgical technique, shorter operative time, decreased blood loss, improved biomechanics, earlier patient immobilization and shorter length of stay. There is no published evidence to support any of these claims. In fact, the only consistent difference found in the literature between the two fixation techniques is an increased rate of complications particularly intraoperative and postoperative fractures and a higher rate of reoperation in association with the intramedullary nail1,2,3.

Verattas in 2009 prospectively randomized 120 consecutive intertrochanteric hip fractures to either extramedullary or intramedullary fixation to examine the systemic effects of surgical treatment4. Bleeding, postoperative pain, postoperative morbidity and recovery of function were not significantly different between either group.

A large Cochrane Collaboration was published in September of 2010 reviewing 43 trials comparing the Gamma and other intramedullary nails versus extramedullary implants for extracapsular hip fractures in adults1. This meta-analysis involved a total of 4766 patients and concluded, "with its lower complication rate in comparison with intramedullary nails, and the absence of functional outcome data to the contrary, the sliding hip screw appears superior for trochanteric fractures". The work also points out that intramedullary fixation has been associated with a significantly increased risk of adverse events particularly intraoperative and late fracture around or below the implant. While it is plausible that more recent changes in nail design could reduce the frequency of these complications, there is no published evidence so far demonstrating superiority over the sliding screw in respect to these complications or of any functional advantage for patients.

Cost is also an important issue in this debate. In Alberta the surgical fee code for intramedullary fixation of intertrochanteric hip fractures is 25% greater than the code for a dynamic hip screw. As well, the costs of the implants are not equal. Although there are regional variations, the intramedullary nail is consistently significantly more expensive than a dynamic hip screw. Furthermore there is no objective evidence to corroborate claimed cost savings through shorter operative times, decreased hospital stays, improved functional outcome, or decrease morbidity with intramedullary nails.

Bottom Line...
For AO type 3 fractures, reverse obliquity and subtrochanteric fractures, the intramedullary nail does have clear and documented advantages over the sliding hip screw5,6.

duffy2
Figure 2: Late non union and failure of fixation . Progressive varus deformity will ensue if not revised.

For AO type A1 and A2 intertrochanteric fractures, however; the sliding hip screw has had a long track record dating back to the 1950s. The significant increase in the use of intramedullary fixation over the past number of years is not justified based on the orthopaedic literature. Intramedullary fixation is more costly both in terms of implant cost and surgeon fees. There is clearly no improvement in functional outcome or patient well-being. There is a documented increased risk of adverse events: particularly fractures around the implant.

For AO A1, A2 intertrochanteric hip fractures, be confident in the use of a sliding hip screw as an appropriate proven, cost-effective choice.

References

  1. Anglen J.O., Weinstein J.N.; American Board of Orthopaedic Surgery Research Committee. Nail or plate fixation of intertrochanteric hip fractures: changing pattern of practice. A review of the American Board of Orthopaedic Surgery Database. J Bone Joint Surg Am. 2008 Apr;90(4):700-7.
  2. Parker M.J., Handoll H.H. Gamma and other cephalocondylic intramedullary nails versus extramedullary implants for extracapsular hip fractures in adults. Cochrane Database Syst Rev. 2010 Sep 8;(9):CD000093. Review.
  3. Barton T.M., Gleeson R., Topliss C., Greenwood R., Harries W.J., Chesser T.J. 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 Joint Surg Am. 2010 Apr;92(4):792-8.
  4. Verettas D.A., Ifantidis P., Chatzipapas C.N., Drosos G.I., Xarchas K.C., Chloropoulou P., Kazakos K.I., Trypsianis G., Ververidis A. Systematic effects of surgical treatment of hip fractures: gliding screw-plating vs intramedullary nailing. Injury. 2010 Mar;41(3):279-84.
  5. Kuzyk P.R., Bhandari M., McKee M.D., Russell T.A., Schemitsch E.H. Intramedullary versus extramedullary fixation for subtrochanteric femur fractures. J Orthop Trauma. 2009 Jul;23(6):465-70.
  6. Kuzyk P.R., Lobo J., Whelan D., Zdero R., McKee M.D., Schemitsch E.H. Biomechanical evaluation of extramedullary versus intramedullary fixation for reverse obliquity intertrochanteric fractures. J Orthop Trauma. 2009 Jan;23(1):31-8.

 

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