High Yield Topics

Subtrochanteric Fracture

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Ovid: 5-Minute Orthopaedic Consult

Editors: Frassica, Frank J.; Sponseller, Paul D.; Wilckens, John H.
Title: 5-Minute Orthopaedic Consult, 2nd Edition
> Table of Contents > Subtrochanteric Fracture

Subtrochanteric Fracture
Carl Wierks MD
Emmanuel Hostin MD
Basics
Description
  • By definition, subtrochanteric hip
    fractures (or, simply, subtrochanteric fractures) extend into the
    region between the lesser trochanter and a point 5 cm distally.
  • Classification:
    • Multiple systems exist, but
      prognostically the most critical factor is fracture stability, which is
      based on the degrees of comminution of the medial and posteromedial
      cortex.
    • The Russell and Taylor classification (1):
      • Useful for guiding treatment because it differentiates fractures that extend into the piriformis fossa from those that do not.
      • This distinction is important because a
        cephalomedullary nail enters the femur at the piriformis fossa and
        therefore should not be used if the fossa is fractured (2).
  • The medial and posteromedial cortices sustain the great compressive forces.
    • Comminution in this area renders the fracture unstable.
General Prevention
  • Fall precautions in the elderly
  • Wearing safety belts in automobiles
Epidemiology
  • A bimodal age distribution:
    • 1/3 of these fractures occur in patients ≤50 years old (3).
  • Young patients typically present after
    undergoing high-energy trauma, whereas low-energy trauma is the typical
    cause in the geriatric population (3).
Incidence
Subtrochanteric fractures account for ~10–34% of all hip fractures (3).
Risk Factors
Any condition that generally (such as osteoporosis) or
focally (such as metastatic disease) weakens the bone may predispose to
such an injury with low-energy trauma or even without trauma.
Etiology
  • In young patients with normal bone, the
    mechanism of injury is high-energy trauma, as occurs in motor vehicle
    collisions, falls from substantial heights, or gunshot wounds.
  • In the geriatric population with weakened bone, low-energy trauma (such as a minor fall) is a more common cause.
  • Less commonly, the pathologic fracture
    occurs in which weakened bone stock (e.g., secondary to neoplasm or
    metabolic bone disease) is unable to withstand the mechanical stresses
    of normal ambulation or other low-impact activity.
  • The mechanical stresses on the femur are highest in the subtrochanteric region.
Associated Conditions
  • When the fracture is associated with
    high-energy trauma, a high index of suspicion should exist for other
    injuries in the ipsilateral extremity or pelvis and elsewhere (e.g.,
    cranial and vertebral injuries).
  • These injuries can be associated with substantial hemorrhage; therefore, the patient should be monitored for hypovolemic shock.
  • In addition, compartment syndrome of the thigh is possible, although rare.
  • With any such fracture associated with
    previous symptoms of pain, a limp, or with minimal trauma, neoplasm
    should be ruled out by appropriate methods, including bone biopsy at
    the time of treatment.
Diagnosis
Signs and Symptoms
  • The clinical picture often is not subtle
    and resembles that in any patient with an intertrochanteric or a
    femoral shaft fracture.
  • Pain and deformity are common, although nondisplaced fractures also are seen.
History
Trauma or fall
Physical Exam
  • Generally, a shortened extremity with a swollen thigh is most evident on examination.
  • A complete neurovascular examination of the extremity should be performed.
  • An open injury should be ruled out.
Tests
Lab
  • A complete blood count to evaluate the hematocrit is advisable in patients with any trauma.
    • Preoperative laboratory tests should be obtained in case operative treatment is necessary.
  • Urine and serum electrophoresis may be obtained if pathologic fracture is suspected.
Imaging
  • Radiography:
    • AP radiographs of the pelvis and AP and
      lateral films of the hip and femur should be obtained with particular
      attention being paid to including the femoral neck to rule out
      concurrent, ipsilateral injury and to help dictate treatment options.
    • The “cross-table lateral” hip view is advised rather than the “frog-leg” view.
Pathophysiology
  • The proximal portion of the femur is
    pulled into abduction, external rotation, and flexion by the gluteus,
    external rotator, and iliopsoas muscles, respectively.
  • The distal fragment is pulled proximally and into varus by the iliopsoas, producing a shortened femur with varus deformation.
  • Recognition of these deformities is important and aids the surgeon in reducing the fracture.
Differential Diagnosis
  • Traumatic injury
  • Pathologic fracture
Treatment
General Measures
  • Initial assessment after the trauma includes the ATLS (4) protocol when appropriate.
    • Treatment of any urgent concomitant injuries should be done while traction splinting is in place.
  • Skeletal traction should be initiated if
    the patient is going to be treated nonoperatively or if surgical
    fixation will be delayed.
  • Nonoperative treatment may be indicated for elderly patients who are poor operative candidates.
    • Skeletal traction or cast bracing may be
      used, although these treatments commonly result in shortening,
      rotational or varus deformity, malunion, or nonunion.
  • After the immediate posttraumatic
    stabilization and workup, medical issues include intravascular volume,
    antithromboembolic prophylaxis (keeping in mind the timing of
    definitive surgical management), and treatment of pre-existing medical
    problems.
Pediatric Considerations
  • Unless the bone is weakened by an
    inherent process such as a simple bone cyst, fibrous dysplasia, or
    osteoporosis, subtrochanteric femur fractures in children are secondary
    to high-energy trauma and much less common than more proximal femoral
    fractures.
  • The vascular supply to the femoral head is not at risk as it is in femoral neck fractures.
  • The potential for leg-length discrepancy is present even if no obvious damage to the physis is present.
    • Attention to leg length and rotational orientation should be a priority during treatment (5).
  • Treatment can involve closed reduction and spica cast, external fixation, or internal fixation.

P.429


Activity
  • Patients should be nonweightbearing until definitive stabilization of the fracture.
  • Postoperative weightbearing:
    • Toe-touch weightbearing with crutches or a walker should be initiated within the first 2–3 days.
    • Full weightbearing should be achieved gradually over a 3-month period, guided by radiographic healing.
  • Elderly patients are allowed to bear weight as tolerated.
Special Therapy
Physical Therapy
Patients may begin ROM and hip strengthening in the early postoperative period.
Medication
Narcotic pain medicines are necessary after subtrochanteric fractures.
Surgery
  • Open reduction and internal fixation
    comprise the treatment of choice for most fractures because this
    approach allows for early mobilization and better achieves near-normal
    anatomy than do nonoperative procedures.
  • The goals of treatment are to restore
    femoral length and rotational alignment and to maintain the abductor
    muscle lever arm by preventing varus deformity.
  • Because this area of the femur undergoes
    substantial compressive and tensile stresses with normal gait, implant
    failure is of concern, particularly with unstable fractures.
  • The main operative treatment options
    include static interlocking nails, cephalomedullary reconstruction
    nails with locking screws placed into the femoral head, a sliding hip
    screw, and a 95° angled blade plate (6).
    • Static interlocking nails can be used if both trochanters are intact.
    • Cephalomedullary nails are indicated if loss of the posteromedial cortex is present.
    • A sliding hip screw can be used only for
      proximal fractures because the compression screw must cross the
      fracture and, for compression to occur, the plate cannot be fixed to
      the proximal fragment.
    • A device called the Medoff plate allows sliding along the head–neck axis and the shaft.
      • Results in a blinded study comparing the Medoff plate to an intramedullary nail favored the use of the nail (7).
      • A 95° angled blade plate has been shown
        to provide good results when a sliding hip screw cannot be used because
        of comminution in the trochanteric area and fracture extension into the
        lateral cortex (8).
      • Dynamic condylar screw plate fixation is not as reliable as intramedullary nail fixation (9).
Follow-up
  • Patients should be seen within 1–2 weeks after surgical fixation to confirm fracture and implant stability.
  • Subsequently, they should be seen monthly to assess healing radiographically and clinically.
Prognosis
  • Most patients can return to near-prefracture activity level, given appropriate treatment (10).
  • A recent review (11) of 302 patients with low-energy subtrochanteric fractures treated with a cephalomedullary nails found that:
    • At 1 year, 34.5% of the patients had died.
    • Survivors had an increased level of social dependence, an increased use of walking aids, and reduced mobility.
    • Of the 211 patients who were evaluated at
      1 year after the injury, 42% had some degree of hip discomfort but only
      2 described the pain as severe and disabling.
    • Reoperation was required in 8.9% of the patients, with a 1-year nail revision rate of 7.1%.
    • 2% of the patients had nonunion.
Complications
  • The most common complications of treatment of subtrochanteric fractures are nonunion, malunion, shortening, and implant failure.
  • Stable, near-anatomic reduction and
    internal fixation of these injuries with attention paid to avoiding
    premature weightbearing help decrease the incidence of such
    complications.
  • Loss of fixation in plate and screw
    devices usually is secondary to screw pullout from the femoral head in
    osteoporotic bone and should be managed with revision to an
    intramedullary nail (12).
  • Failure of interlocking nails can be
    secondary to failure to lock the device statically, fracture at the
    entry site, or an undersized nail.
    • These complications can be treated with nail replacement using a larger-diameter nail.
  • Penetration of the distal anterior femoral cortex also is a potential complication with an intramedullary nail (13).
  • Nonunion is defined by pain or tenderness at the fracture site after 3–6 months.
  • Symptoms of malunion include limp, rotational deformity, and leg-length discrepancy.
    • Treatment involves valgus osteotomy, revision internal fixation, and bone grafting.
  • AVN of the femoral head may occur in
    children with open physes, if standard intramedullary nailing is
    performed through the piriformis fossa.
References
1. Russell
TA, Taylor JC. Subtrochanteric fractures of the femur. In: Browner BD,
Jupiter JB, Levine AM, et al., eds. Skeletal Trauma. Fractures,
Dislocations, Ligamentous Injuries. Philadelphia: WB Saunders,
1992:1485–1524.
2. Sims SH. Subtrochanteric femur fractures. Orthop Clin North Am 2002;33:113–126.
3. Bedi A, Le TT. Subtrochanteric femur fractures. Orthop Clin North Am 2004;35:473–483.
4. American
College of Surgeons Committee on Trauma. Advanced Trauma Life Support
Program for Doctors, 6th ed. Chicago: American College of Surgeons,
1997.
5. Jarvis J, Davidson D, Letts M. Management of subtrochanteric fractures in skeletally immature adolescents. J Trauma 2006;60:613–619.
6. Kregor PJ, Obremskey WT, Kreder HJ, et al. Unstable pertrochanteric femoral fractures. J Orthop Trauma 2005;19:63–66.
7. Miedel
R, Ponzer S, Tornkvist H, et al. The standard Gamma nail or the Medoff
sliding plate for unstable trochanteric and subtrochanteric fractures.
A randomised, controlled trial. J Bone Joint Surg 2005;87B:68–75.
8. Yoo MC, Cho YJ, Kim KI, et al. Treatment of unstable peritrochanteric femoral fractures using a 95 degrees angled blade plate. J Orthop Trauma 2005;19:687–692.
9. Kulkarni SS, Moran CG. Results of dynamic condylar screw for subtrochanteric fractures. Injury 2003;34:117–122.
10. Cheng
MT, Chiu FY, Chuang TY, et al. Treatment of complex subtrochanteric
fracture with the long gamma anteroposterior locking nail: A
prospective evaluation of 64 cases. J Trauma 2005;58:304–311.
11. Robinson
CM, Houshian S, Khan LA. Trochanteric-entry long cephalomedullary
nailing of subtrochanteric fractures caused by low-energy trauma. J Bone Joint Surg 2005;87A:2217–2226.
12. Barquet
A, Mayora G, Fregeiro J, et al. The treatment of subtrochanteric
nonunions with the long gamma nail: Twenty-six patients with a minimum
2-year follow-up. J Orthop Trauma 2004;18:346–353.
13. Ostrum
RF, Levy MS. Penetration of the distal femoral anterior cortex during
intramedullary nailing for subtrochanteric fractures: A report of three
cases. J Orthop Trauma 2005;19:656–660.
Miscellaneous
Codes
ICD9-CM
820.32 Subtrochanteric fracture
Patient Teaching
  • Patients should be advised of the risk of malunion, nonunion, or implant failure, especially if they have osteoporotic bone.
  • Protected weightbearing in the early
    postoperative period is essential to allow adequate reconstitution of
    this mechanically stressed area.
FAQ
Q: What is the best treatment for a subtrochanteric femur fracture?
A:
Intramedullary nailing using a cephalomedullary device allows for
stable fixation of subtrochanteric fractures. Reduction and anatomic
fixation is paramount. The fracture must be reduced before nail
insertion.

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