Traumatic Knee Pain
Article Outline
[Ann Emerg Med. 2009;53:403.]
A 19-year-old man presented after riding a 125-cc dirt bike. While accelerating, the bike slipped out from underneath him, and he fell onto his left side. He presented with pain in his left knee after his flexed knee went into extreme varus alignment. His physical examination result was notable for diffuse left knee swelling, ecchymosis of medial knee, and a large intraarticular knee effusion. Patellar apprehension test result was negative, and the Lachman's test result was positive. Knee motion was limited from –8 to 60 degrees of flexion. There was a firm endpoint with posterior drawer testing at the above mentioned flexion angle. The remainder of the ligamentous knee examination was limited as a result of pain and guarding. Radiographs were obtained (Figure 1).
Figure 1.
Radiograph of the knee demonstrating a small vertical avulsion injury of the lateral aspect of the proximal tibia immediately distal to the tibial plateau.
Diagnosis
Segond fracture
The Segond fracture is a small vertical avulsion injury of the lateral aspect of the proximal tibia immediately distal to the tibial plateau. The mechanism of injury is an axial load on a semiflexed knee, with internal rotation and varus stress.1, 2 The fracture has a strong association with an anterior cruciate ligament tear (75% to 100%), as well as meniscal injury (67% to 75%)3, 4, 5, 6 (Figure 2). A hemarthrosis is commonly present.3 Clinically, signs of anterior instability such as a positive pivot-shift test result, Lachman's test, and anterior draw sign may be present.5 The most specific clinical test is the pivot-shift test, but false-negative results may occur from a locked knee or guarding.4 Furthermore, physical examination (Lachman's and anterior draw test) to evaluate the function of the anterior cruciate ligament may be unreliable as result of pain, hamstring resistance, or effusion.7 Radiographically, the bone fragment is located on the lateral edge of the tibial condyle and is best visualized on the anterior-posterior view. The Segond fragment, seen on plain radiograph, is identified by magnetic resonance imaging only in one third of cases.6 Although magnetic resonance imaging is not sensitive in the detection of the Segond fracture fragment, it is useful in demonstrating associated ligamentous and meniscal injuries.6
Figure 2.
Illustration demonstrating the anterior cruciate ligament tear, meniscal injury, and a small vertical avulsion fracture of the lateral aspect of the proximal tibia immediately distal to the tibial plateau. Used with permission of James E. Colletti, MD, Department of Emergency Medicine, Mayo Clinic, Rochester, MN.
Management entails elevation, ice application, crutches, knee immobilization, and prompt orthopedic referral.7 Consideration should be given to drainage of tense effusions for pain relief.
References
- . Segond fracture: lateral capsular ligament avulsion. J Orthop Sports Phys Ther. 1997;25:103–106
- . Segond fractures of the lateral tibial condyle: brief report. J Bone Joint Surg. 1987;69-B:613–614
- . Segond tibial condyle fracture: lateral capsular ligament avulsion. Radiology. 1986;159:467–469
- . The Segond fracture of the proximal tibia: a small avulsion that reflects major ligamentous damage. AJR Am J Roentgenol. 1988;151:1163–1167
- Radiologic case study (Segond fracture). Orthopedics. 2007;30:689;688
- Lateral tibial rim (Segond) fractures: MR imaging characteristics. Radiology. 1991;180:731–734
- . Segond fracture, hemarthrosis, and anterior cruciate ligament disruption. J Emerg Med. 1990;8:29–33
For the diagnosis and teaching points, see page 409.
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PII: S0196-0644(08)01395-4
doi:10.1016/j.annemergmed.2008.06.462
© 2008 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.
