AUTHOR AND EDITOR INFORMATION

Section 1 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

INTRODUCTION

Section 2 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Background

Fractures of the knee include fractures of the patella, femoral condyles, tibial eminence, tibial tuberosity, and tibial plateau. Direct and indirect forces can cause these fractures.

Frequency

United States

Patellar and tibial plateau fractures each account for 1% of all skeletal fractures. Distal femoral condyle fractures account for 4% of all femur fractures.

Mortality/Morbidity

• Fractures of the knee can result in neurovascular compromise or compartment syndrome, with resultant risk of limb loss. Soft-tissue infection or osteomyelitis can occur with open fractures.
• Other complications include nonunion, delayed union, osteoarthritis, avascular necrosis, fat embolism, and thrombophlebitis.

CLINICAL

Section 3 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

History

Patients with knee fractures may have a history of the following:

• Direct or indirect trauma with resultant pain and edema
• Patella fracture
• • Caused by a direct blow, such as a dashboard injury in a motor vehicle accident or a fall on a flexed knee
  • Also caused by forceful quadriceps contraction while the knee is in the semiflexed position (eg, in a stumble or fall)
• Femoral condyle fractures due to axial loading with valgus or varus stress
• Tibial eminence fracture
• • Due to a direct blow to the proximal tibia with the knee flexed such as falling off a bicycle
  • Also due to hyperextension with varus or valgus stress, such as in motor vehicle collisions or athletic accidents
  • Tibial eminence avulsion fractures occur most often in children aged 8-14 years but can also occur in the skeletally mature patient.
• Tibial tubercle fracture
• • Usually occur with jumping activities such as basketball, diving, gymnastics, and football 
  • More common in males than in females
  • More common in adolescents; infrequent in adults
• Tibial plateau fracture
• • Caused by axial loading with valgus or varus forces, such as in a fall from a height or collision with the bumper of a car
  • Due to the impaction of the femoral condyle into the tibial plateau
  • In elderly persons and those with osteoporosis, tibial plateau fracture can occur with minor trauma.
  • Patient is generally unable to bear weight.
  • The lateral tibial plateau is fractured more frequently than the medial plateau.

Physical

When examining a patient for a knee fracture, one should first examine the patient for edema, ecchymosis, and point tenderness. A careful neurovascular examination should be performed. Ask the patient to perform a straight-leg raise against gravity to check the integrity of the extensor mechanism, which commonly is disrupted with transverse patellar fractures caused by indirect forces. 

• Patella fractures
• • Patients present with pain directly over the patella.
  • The patient may have pain with leg extension or be unable to extend the knee with a severe fracture.
• Femoral condyle fractures
• • Patient will present with pain over the distal femur and often will have a hemarthrosis.
  • Patients are often unable to bear weight.
• Tibial eminence fractures
• • Patients may present with a knee effusion and pain.
  • Patients may represent with an avulsion of the tibial attachment of the anterior cruciate ligament.
• Tibial tubercle fractures
• • Patients present with pain over the anterior tibia about 3 cm distal to the articular surface.
  • In severe fractures, the patient may be unable to extend the knee.
• Tibial plateau fractures
• • Often, patients present with a knee effusion, and tenderness will be present over the medial or lateral plateau.
  • Up to 30% of tibial plateau fractures are associated with knee ligamentous injuries (medial collateral or anterior cruciate ligaments with lateral plateau fractures, lateral collateral or posterior cruciate ligaments with medial plateau fractures).

Causes

Knee fractures may be caused by the following:

• Trauma (direct or indirect)
• Chronic stress
• Pathologic conditions

DIFFERENTIALS

Section 4 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Other Problems to be Considered

• Bipartite patella
• • A congential fragmentation of the patella 
  • Has smooth cortical margins
  • Most common location is superolateral pole of patella; however, it can occur in the inferior pole or the lateral margin. 
• Stress fractures
• Ligamentous injuries

WORKUP

Section 5 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Imaging Studies

• Radiographs
• • Obtain anteroposterior, lateral, and oblique radiographs of the knee. Four views have been shown to be superior to two views in detecting fractures.
  • Oblique views are particularly useful in detecting subtle tibial plateau fractures (internal oblique profiles lateral plateau, external oblique profiles medial plateau). Oblique views also better identify obliquely oriented femoral condyle fractures.
  • An axial (or sunrise) view of the patella is useful for detecting vertical patellar fractures, which frequently are missed and nondisplaced. Transverse fractures are most common, followed by comminuted and avulsion-fractures. Adding a sunrise view increases the negative predictive value of radiographs for ruling out patellar fracture.
  • A fat-fluid level (lipohemarthrosis) may be identified on a lateral view of the knee; this finding indicates an intra-articular fracture.
  • Radiographic evidence of ligamentous injury may be present:
  • • An avulsion fracture at the site of attachment of the lateral capsular ligament on the lateral tibial condyle (Segond fracture) is a marker for anterior cruciate ligament rupture.
    • Cortical avulsion fracture of medial tibial plateau (uncommon) is associated with tears of the posterior cruciate ligament and medial meniscus.
  • A patellar spur at the superior portion of the patella is associated with a ruptured quadriceps tendon.
  • Use of the Ottawa rules for obtaining knee radiographs have proven sensitive for fracture and have reduced ED waiting times and costs. The rules include the following patient findings:
    • Age 55 years or older
    • Tenderness at head of fibula
    • Isolated tenderness of patella
    • Inability to flex knee to 90 degrees 
    • Inability to bear weight (4 steps) immediately after injury and in ED
• CT scans and MRIs
• • CT scans may be necessary to fully delineate the extent of tibial plateau fractures and other complex knee fractures.
  • Compared to CT scans, plain radiography underestimates the amount of articular depression of tibial plateau fractures in most tibial regions. This is significant as the amount of tibial plateau depression is an indicator for operative repair.
  • CT scans are also useful in severely injured patients when obtaining radiographs in all angles is difficult.
  • MRIs also are useful and have the added benefit of depicting associated soft-tissue (eg, ligamentous, meniscal) injury.

Procedures

• Arthrocentesis may be of diagnostic and therapeutic benefit for tense effusions. Presence of blood and glistening fat globules indicates lipohemarthrosis, which is pathognomonic for intraarticular knee fracture.

TREATMENT

Section 6 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Prehospital Care

• Document the neurovascular status.
• Apply a sterile dressing to open wounds.
• Splint the injury.
• Administer parenteral analgesics for isolated extremity injury.

Emergency Department Care

Care for various fractures is as follows:

• Patellar fracture
• • Nondisplaced transverse fractures with an intact extensor mechanism are treated with a knee immobilizer, crutches, restriction to only partial weight bearing, and 6 weeks of immobilization.
  • Displaced fractures, or fractures associated with a disrupted extensor mechanism, are referred to orthopedics for possible open reduction and internal fixation. A partial or total patellectomy may be required for severe comminution.
  • Patients with open fractures should receive antibiotics and orthopedics should be consulted for emergency irrigation and debridement.
• Femoral condyle fracture
  • These may be supracondylar, intercondylar, or condylar.
  • Due to the proximity of the neurovascular structures, a thorough neurovascular examination must be obtained.
  • Obtain an orthopedic consult. Nonoperative management may be used for nondisplaced or incomplete fractures. Open fractures, displaced fractures, and those with neurovascular injury will need operative fixation.
• Tibial spine fracture
• • For a nondisplaced fracture (and stable knee joint), immobilize the knee.
  • Obtain an orthopedic consultation for an unstable knee, a complete avulsion of the tibial spine, or a displaced fracture for possible surgical fixation.
• Tibial tubercle fracture
• • For nondisplaced fractures, immobilize the knee.
  • Obtain an orthopedic consultation for displaced fracture to consider open reduction and internal fixation.
• Tibial plateau fracture
• • Immobilize nondisplaced fractures and have patient remain nonweightbearing.
  • Obtain an orthopedic consultation for displaced (depressed) fractures, which require open reduction and internal fixation. Articular depression of greater than 3 mm may be considered for surgery.
  • The goal of treatment is a stable, aligned, mobile, and painless knee joint to minimize risk of posttraumatic osteoarthritis.

Consultations

• Orthopedic referral is recommended for all knee fractures.
• Nondisplaced fractures may be splinted, with orthopedic follow-up care within a few days.
• Displaced or open fractures require prompt orthopedic consultation.

MEDICATION

Section 7 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Opioid analgesics and nonsteroidal anti-inflammatory agents are the DOCs for pain associated with fractures.

Drug Category: Nonsteroidal anti-inflammatory drugs (NSAIDs)

Most commonly used for relief of mild to moderate pain. Effects of NSAIDs in the treatment of pain tend to be patient specific, yet ibuprofen usually is the DOC for initial therapy. Other options include flurbiprofen, ketoprofen, and naproxen.

Drug Category: Analgesics

Pain control is essential to quality patient care. It ensures patient comfort, promotes pulmonary toilet, and aids physical therapy regimens. Many analgesics have sedating properties that benefit patients who have sustained fractures.

FOLLOW-UP

Section 8 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Transfer

• Transfer is appropriate if inpatient beds or operating rooms are unavailable or if an orthopedic specialist's services are indicated.

Complications

• Neurovascular injury
• • Popliteal artery injury due to displaced distal femur or tibial plateau fractures
  • Peroneal nerve injury due to proximal fibula fractures
• Compartment syndrome of the lower leg
• • Signs of compartment syndrome include pain with passive movement of the involved muscles, paresthesias, pallor, and a very late finding of pulselessness.
  • Compartment syndrome by definition has increased compartment pressures; therefore, palpation of the affected area frequently aids in the diagnosis.  However, a soft extremity does not rule out compartment syndrome.
  • If compartment syndrome is suspected, obtain an emergent orthopedic consultation and measure the compartment pressures. If untreated, increased compartment syndrome can cause permanent disability.
• Soft-tissue infection
• Osteomyelitis secondary to an open fracture
• Delayed union or nonunion
• Fat embolism
• Thrombophlebitis
• Posttraumatic arthritis or knee stiffness
• Chondromalacia patella

Prognosis

• A good prognosis is expected with patellar and tibial spine or tubercle fractures.
• A fair prognosis is expected with tibial plateau and femoral condyle fractures. A recent prospective study in patients with tibial plateau fractures showed that only 14% of patients recover full quadriceps muscle strength 1 year after injury. Also, 20% will have residual knee stiffness after 1 year.

Patient Education

• For excellent patient education resources, visit eMedicine's Breaks, Fractures, and Dislocations Center. Also, see eMedicine's patient education articles, Knee Dislocation and Knee Injury.

MISCELLANEOUS

Section 9 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical/Legal Pitfalls

• Failure to identify neurovascular injury
• Failure to identify open fractures and obtain urgent orthopedic consultation
• Failure to check the integrity of and to identify injuries to extensor mechanism of the knee
• Failure to identify patients at risk of developing a compartment syndrome

REFERENCES

Section 10 of 10

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

• Accousti WK, Willis RB. Tibial eminence fractures. Orthop Clin North Am. Jul 2003;34(3):365-75. [Medline].
• Bharam S, Vrahas MS, Fu FH. Knee fractures in the athlete. Orthop Clin North Am. Jul 2002;33(3):565-74. [Medline].
• Davis DS, Post WR. Segond fracture: lateral capsular ligament avulsion. J Orthop Sports Phys Ther. Feb 1997;25(2):103-6. [Medline].
• Gaston P, Will EM, Keating JF. Recovery of knee function following fracture of the tibial plateau. J Bone Joint Surg Br. Sep 2005;87(9):1233-6. [Medline].
• Gray SD, Kaplan PA, Dussault RG. Acute knee trauma: how many plain film views are necessary for the initial examination?. Skeletal Radiol. May 1997;26(5):298-302. [Medline].
• Hall FM, Hochman MG. Medial Segond-type fracture: cortical avulsion off the medial tibial plateau associated with tears of the posterior cruciate ligament and medial meniscus. Skeletal Radiol. Sep 1997;26(9):553-5. [Medline].
• Hardy JR, Chimutengwende-Gordon M, Bakar I. Rupture of the quadriceps tendon: an association with a patellar spur. J Bone Joint Surg Br. Oct 2005;87(10):1361-3. [Medline].
• Kilgore KP. The knee. In: Emergency Management of Skeletal Injuries. St Louis, Mo: Mosby-Year Book; 1995:439-99.
• Konstantakos EK, Dalstrom DJ, Nelles ME, Laughlin RT, Prayson MJ. Diagnosis and management of extremity compartment syndromes: an orthopaedic perspective. Am Surg. Dec 2007;73(12):1199-209. [Medline].
• Koval KJ, Zuckerman JD. Lower extremity fractures and dislocations. In: Handbook of Fractures. 2002:210-234.
• Mustonen AO, Koskinen SK, Kiuru MJ. Acute knee trauma: analysis of multidetector computed tomography findings and comparison with conventional radiography. Acta Radiol. Dec 2005;46(8):866-74. [Medline].
• Mustonen AO, Koskinen SK, Kiuru MJ. Acute knee trauma: analysis of multidetector computed tomography findings and comparison with conventional radiography. Acta Radiol. Dec 2005;46(8):866-74. [Medline].
• Newton EJ, Love J. Emergency department management of selected orthopedic injuries. Emerg Med Clin North Am. Aug 2007;25(3):763-93, ix-x. [Medline].
• Nichol G, Stiell IG, Wells GA. An economic analysis of the Ottawa knee rule. Ann Emerg Med. Oct 1999;34(4 Pt 1):438-47. [Medline].
• Roberts DM, Stallard TC. Emergency department evaluation and treatment of knee and leg injuries. Emerg Med Clin North Am. Feb 2000;18(1):67-84, v-vi. [Medline].
• Sanders AK, Boggess BR, Koenig SJ. Medicolegal issues in sports medicine. Clin Orthop Relat Res. Apr 2005;38-49. [Medline].
• Stiell IG, Wells GA, Hoag RH. Implementation of the Ottawa Knee Rule for the use of radiography in acute knee injuries. JAMA. Dec 17 1997;278(23):2075-9. [Medline].
• Thomas AL, Wilson RH, Thompson TL. Quadriceps avulsion through a bipartite patella. Orthopedics. Jun 2007;30(6):491-2. [Medline].
• Walker CW, Moore TE. Imaging of skeletal and soft tissue injuries in and around the knee. Radiol Clin North Am. May 1997;35(3):631-53. [Medline].
• Wiss DA, Watson JT, Johnson EE. Fractures of the knee. In: Fractures in Adults. 4^th ed. Philadelphia, Pa: Lippincott-Raven; 1996:1919-2001.

Article Last Updated: Mar 31, 2008