High Yield Topics

Knee Supracondylar 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 > Knee Supracondylar Fracture

Knee Supracondylar Fracture
Carl Wierks MD
David Solacoff MD
Basics
Description
  • These fractures involve the supracondylar (metaphyseal) area of the distal femur.
  • Classification AO/ASIF (1):
    • Type A: Extra-articular:
      • A1: Simple fracture
      • A2: Metaphyseal wedge
      • A3: Comminuted metaphyseal fracture
    • Type B: Unicondylar:
      • B1: Lateral condyle
      • B2: Medial condyle
      • B3: Fracture in the frontal plane
    • Type C: No part of the joint is attached to the shaft.
      • C1: Simple articular fracture with simple metaphyseal fracture
      • C2: Simple articular fracture with comminuted metaphyseal fracture
      • C3: Fractures with articular comminution
  • Synonym: Distal femur fracture
Epidemiology
Incidence
  • Up to 30% of all femur fractures (2)
  • Less common than femoral shaft fractures
  • Most pediatric supracondylar femur fractures occur in adolescents.
  • 2 peaks (3):
    • Young (<35 years old): High-energy fractures
    • Older (>50 years old): Low-energy fractures
  • In the young, high-energy group, males are affected more commonly than females.
  • In the older, low-energy group, females are affected more often than males.
  • Osteopenia is prevalent in the older, low-energy group.
Risk Factors
Risk factors in the older group are osteopenia and previous age-related fractures.
Etiology
  • Young group: High-energy trauma (e.g., motor vehicle collision, falls from heights)
  • Older group: Low-energy trauma (e.g., falls on flexed knee)
  • Rarely, a complication of total knee arthroplasty
  • In pediatric patients, injuries usually
    are traumatic, with the fracture exiting at the metaphysis on the
    compression side, resulting in a Salter-Harris type II fracture (4).
Associated Conditions
  • Acetabular fractures
  • Hip dislocations
  • Femoral neck and shaft fractures
  • Knee ligamentous injuries
  • Tibial plateau and shaft fractures
  • Femoral artery disruptions
Diagnosis
Signs and Symptoms
  • Pain
  • Tenderness to palpation
  • Edema
  • Deformity
  • Inability to walk
  • Ecchymosis
Physical Exam
  • Complete musculoskeletal and neurovascular examination is essential.
  • Full examination of the knee is difficult until after fracture fixation.
Pathological Findings
  • Muscle spasm often leads to shortening of the femur and limb.
  • The femoral shaft often overrides
    anteriorly as the gastrocnemius pulls the distal fragment posteriorly
    into an apex-anterior deformity.
  • The adductors often cause a varus deformity.
Tests
Imaging
  • Radiography:
    • Knee:
      • AP and lateral radiographs of the knee and supracondylar region
      • 45° oblique radiographs if intercondylar involvement is present
    • Pelvis:
      • AP radiograph (to rule out other fractures) in trauma settings
    • Hip and femur:
      • AP and lateral radiographs of the hip and the whole femur (to rule out other fractures) in trauma settings
  • Angiogram if distal vascular status is questionable
  • CT may be beneficial for operative planning for complex fractures.
  • Pediatric patients:
    • Standard trauma radiographs should be obtained.
    • Stress views may be taken when occult injury to the epiphysis is suspected.
    • The physeal line should be 3–5 mm thick until adolescence.
Differential Diagnosis
  • Bruise
  • Knee ligamentous injury
  • Fracture of the patella or proximal tibia
Treatment
General Measures
  • Anatomic articular alignment is paramount.
  • For nondisplaced and impacted fractures, a splint, cast, or fracture brace is used.
  • For extra-articular fractures and medically unstable patients, skeletal traction is an option.
  • For severe open fractures, external fixation is used.
    • May be applied across the knee to provide initial fracture stabilization
    • May be converted to internal fixation when soft-tissue injuries are controlled
  • Open reduction and internal fixation are used for most closed fractures.
  • In pediatric patients with epiphyseal injury, closed reduction with casting can be done if the fracture is stable.
Activity
  • Initial activity should be nonweightbearing on the affected extremity until fracture callus forms.
  • Then, weightbearing is advanced gradually.
Special Therapy
Physical Therapy
  • ROM and quadriceps and hamstring strengthening may begin early postoperatively.
  • The patient can advance to gait training as tolerated.
    • Some advocate toe-touch weightbearing.
  • Progressive weightbearing and resistance
    exercises when clinical and radiographic evidence of healing occurs
    (usually 2–3 months)
  • Complete union usually takes 4–6 months.
Medication
  • Analgesics such as narcotics or acetaminophen are given.
  • NSAIDs are avoided because they may inhibit bone healing.
Surgery
  • Goals are anatomic alignment and stable fixation of the fracture to allow early motion of the limb.
  • Indications include:
    • Open or displaced fractures
    • Fractures with vascular compromise
    • Irreducible fractures
    • Fractures in the patient with multiple injuries or ipsilateral lower-extremity fractures
  • Relative contraindications to surgery include:
    • Infection of the fracture area
    • A medically unstable patient
    • Very osteopenic bone
  • Surgical implant options include:
    • Metal plates angled blade plate
    • Condylar buttress plates
    • Locked plates
    • External fixation
    • Intramedullary nails
    • Total knee replacement

    • P.223


  • Metal plates (5,6):
    • Come in a variety of shapes
    • Can be used with simple and comminuted fractures
    • Can be applied through small incisions and placed on the bone submuscularly
  • External fixation most frequently is used
    to temporize fractures with extensive soft-tissue damage or in the
    unstable, polytrauma patient.
  • Intramedullary nails work well to stabilize comminuted fractures and can be placed antegrade or retrograde.
  • Total knee replacement with distal
    femoral replacement can be used in patients with severe osteopenia or
    pre-existing arthrosis (7).
  • When fractures occur near a knee prosthesis:
    • Fixation can be achieved through a retrograde intramedullary nail, fixed-angle device, or revision arthroplasty.
    • In general, the best treatment choices are (8):
      • Intramedullary nails for proximal fractures
      • Fixed-angle devices for fractures at the level of the implant
      • Revision arthroplasty for distal fractures or those with implant loosening
Pediatric Considerations
  • Closed reduction with percutaneous pinning has been shown to give satisfactory results for displaced pediatric fractures (9).
  • If the fracture is unstable, open reduction with internal fixation can be performed.
  • Postoperatively, the knee is immobilized in 10° of flexion until radiographic evidence of healing is present (~4 weeks).
Follow-up
Disposition
Patients should be monitored closely after initial trauma to rule out the development of compartment syndrome of the thigh.
Prognosis
  • The prognosis depends on the type and severity of the fracture; more complex fractures generally have poorer prognoses.
  • In general, patients have a good to excellent result with appropriate treatment (10).
  • Midterm results of treatment of periprosthetic fractures with intramedullary nails are excellent (11).
Complications
  • Knee stiffness
  • Infection
  • Nonunion
  • Malunion
  • Loss of fixation
  • Traumatic arthritis
  • Compartment syndrome
  • Physeal injury can result in an angular deformity or leg-length inequality.
    • Discrepancies >2.5 cm can be managed by contralateral epiphysiodesis, femoral shortening, or ipsilateral femoral lengthening.
Patient Monitoring
  • Patients are seen initially a few weeks
    after definitive fixation and then approximately monthly until the
    fracture heals and ROM is acceptable.
  • Clinical (pain to palpation) and radiographic (callus) monitoring is done until the fracture is healed.
  • Limited weightbearing may be started when good callus is evident and the patient is not tender to palpation around the fracture.
References
1. Muller
ME, Nazarian S, Koch P, et al. The Comprehensive Classification of
Fractures of Long Bones. Berlin: Springer-Verlag, 1990.
2. Arneson
TJ, Melton LJ, III, Lewallen DG, et al. Epidemiology of diaphyseal and
distal femoral fractures in Rochester, Minnesota, 1965–1984. Clin Orthop Relat Res 1988;234:188–194.
3. Martinet O, Cordey J, Harder Y, et al. The epidemiology of fractures of the distal femur. Injury 2000;31:C62–C63.
4. Salter RB, Harris WR. Injuries involving the epiphyseal plate. J Bone Joint Surg 1963;45A: 587–622.
5. Kregor
PJ, Stannard JA, Zlowodzki M, et al. Treatment of distal femur
fractures using the less invasive stabilization system: surgical
experience and early clinical results in 103 fractures. J Orthop Trauma 2004;18:509–520.
6. Schutz
M, Muller M, Regazzoni P, et al. Use of the less invasive stabilization
system (LISS) in patients with distal femoral (AO33) fractures: a
prospective multicenter study. Arch Orthop Trauma Surg 2005;125:102–108.
7. Rosen AL, Strauss E. Primary total knee arthroplasty for complex distal femur fractures in elderly patients. Clin Orthop Relat Res 2004;425: 101–105.
8. Su ET, DeWal H, Di Cesare PE. Periprosthetic femoral fractures above total knee replacements. J Am Acad Orthop Surg 2004;12:12–20.
9. Butcher
CC, Hoffman EB. Supracondylar fractures of the femur in children:
closed reduction and percutaneous pinning of displaced fractures. J Pediatr Orthop 2005;25:145–148.
10. Weight
M, Collinge C. Early results of the less invasive stabilization system
for mechanically unstable fractures of the distal femur (AO/OTA types
A2, A3, C2, and C3). J Orthop Trauma 2004;18:503–508.
11. Gliatis
J, Megas P, Panagiotopoulos E, et al. Midterm results of treatment with
a retrograde nail for supracondylar periprosthetic fractures of the
femur following total knee arthroplasty. J Orthop Trauma 2005;19:164–170.
Additional Reading
Forster MC, Komarsamy B, Davison JN. Distal femoral fractures: a review of fixation methods. Injury 2006;37:97–108.
Papadokostakis
G, Papakostidis C, Dimitriou R, et al. The role and efficacy of
retrograding nailing for the treatment of diaphyseal and distal femoral
fractures: a systematic review of the literature. Injury 2005;36:813–822.
Miscellaneous
Codes
ICD9-CM
821.23 Femur supracondylar fracture
FAQ
Q: How should a distal femur fracture be treated?
A:
Most fractures are treated with surgery using an intramedullary
retrograde nail or a percutaneous locking plate. Rigid fixation allows
for early motion of the knee to prevent knee stiffness.

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