Lateral collateral ligament injuries
A) Orthopedic surgery referral
B) Place in knee immobilizer for 2 weeks and reassess
C) Early mobilization and physical therapy prescription
D) Order MRI of her knee
Image 1: Lateral knee anatomic image. Adopted from .
history and physical
Due to the uncommon nature of the injury, the provider must examine the knee fully and rule out other concomitant conditions, such as an ACL or PLC injury. Swelling about the lateral soft-tissue envelope of the knee is often present and can correlate with the degree of injury to the ligamentous complex . There will likely be tenderness over the LCL region of the knee and at the fibular head. The LCL can be more easily evaluated for tenderness by having the patient cross their affected leg and resting the foot on the opposite knee (Img. 2). Thirty degrees is the angle at which the maximum amount of varus laxity is observed with application of 10 Nm of force and is of particular importance for clinicians during examination of the integrity of the LCL after injury. Conversely, varus laxity in full extension frequently denotes injury to one or both of the cruciate ligaments. Historically, a varus opening of less than 5 mm has signified a low-grade LCL injury, an opening of 6 to 10 mm has signified a moderate grade injury and an opening of more than 10 mm represented a high-grade injury .
Image 2. Palpation of the lateral collateral ligament positioning. Adopted form .
Imaging normally begins with plain radiographs and these should include weight-bearing radiographs if possible. This is done to rule out any bony lesions of fractures. Stress views (discussed in a previous post) may also be performed. MRI is considered the gold standard for imaging of LCL injuries. Typically, MRI can demonstrate an LCL failure at its fibular attachment or at the midsubstance of the ligament. A poor correlation was found in a small study with roughly 30 patients between examination under anesthesia and MRI results for diagnosis of LCL injuries (58 % sensitivity). This was low compared to ACL injuries (100%) and PLC injuries (87%) . Because these lesions are often found in conjunction with other injuries, it is difficult to determine on physical examination which PLC structure is damaged and the degree of injury to that structure. When available, ultrasound can be a useful tool in the rapid diagnosis of LCL injuries. Imaging will show a thickened and hypoechoic LCL. A complete tear may show edema, dynamic laxity, or lack of LCL fiber continuity.
Treatment involves both nonoperative and operative management and depends on staging and laxity. Involvement or suspected involvement of additional structures may also alter management. Isolated LCL grade I and II tears are normally managed nonsurgically. Early mobilization has been shown to be helpful [9,10]. Recovery time usually ranges from three to eight weeks and a hinged knee sleeve and early physical therapy are benchmarks of nonoperative treatment.
Primary repair is indicated for acute bony avulsions of the femoral or fibular FCL attachment. However, a repair is not recommended for midsubstance tears . Indications for reconstruction include all grade III midsubstance LCL tears and chronic lateral knee instability secondary to FCL injury. More recent evidence has been geared more towards an anatomic technique utilizing a semitendinosus allograft or autograft and has been shown to restore objective knee stability [13,14]. Two separate studies have shown improved subjective and objective outcomes when treating LCL midsubstance tears (Image 3), chronic lateral knee instability and varus stress radiographic gapping of 2.4 to 4.0 mm at 20 degrees flexion [14,15].
Image 3. LCL reconstruction described (anatomic approach). Adopted from .
In summary, lateral collateral ligament injuries in isolation are fairly rare and account for less than 10 percent of knee injuries. The LCL provides stability of the knee when undergoing varus stress and is stressed and isolated best at 30 degrees. Injuries to the LCL typically occur with a direct blow to the anteromedial knee and patients normally present with pain laterally and lateral instability. MRI is the gold standard for imaging but providers should also consider varus stress radiographs. Treatment depends on grading/staging, which is done by physical examination and MRI. Grade I and II injuries are normally treated nonoperatively, while grade III injuries have limited studies but are likely best treated with a more anatomic reconstruction.
- 1. LaPrade RF, Hamilton CD. The fibular collateral ligament- biceps femoris bursa. An anatomic study. Am J Sports Med. 1997;25(4):439–43
2. Grawe, Brian, et al. “Lateral collateral ligament injury about the knee: anatomy, evaluation, and management.” JAAOS-Journal of the American Academy of Orthopaedic Surgeons 26.6 (2018): e120-e127.=6l
3. LaPrade RF, Ly TV, Wentorf FA, Engebretsen L. The posterolateral attachments of the knee: a qualitative and quantitative morphologic analysis of the fibular collateral ligament, popliteus tendon, popliteofibular ligament, and lateral gastrocnemius tendon. Am J Sports Med. 2003 Nov-Dec;31(6):854-60.
4. Swenson DM, Collins CL, Best TM, Flanigan DC, Fields SK, Comstock RD. Epidemiology of knee injuries among U.S. high school athletes, 2005/2006-2010/2011. Med Sci Sports Exerc. 2013 Mar;45(3):462-9.
5. Bushnell BD, Bitting SS, Crain JM, Boublik M, Schlegel TF: Treatment of magnetic resonance imaging-documented isolated grade III lateral collateral ligament injuries in National Football League athletes. Am J Sports Med 2010;38(1):86-91.
6. Veltri DM, Deng XH, Torzilli PA, Warren RF, Maynard MJ. The role of the cruciate and posterolateral ligaments in stability of the knee. A biomechanical study. Am J Sports Med. 1995 Jul-Aug;23(4):436-43.
7. Devitt BM, Whelan DB: Physical examination and imaging of the lateral collateral ligament and posterolateral corner of the knee. Sports Med Arthrosc 2015;23(1):10-16.
8. Bonadio MB, Helito CP, Gury LA, Demange MK, Pécora JR, Angelini FJ. Correlation between magnetic resonance imaging and physical exam in assessment of injuries to posterolateral corner of the knee. Acta Ortop Bras. 2014;22(3):124–126. doi: 10.1590/1413-78522014220300928.
9. Krukhaug Y, Mølster A, Rodt A, Strand T: Lateral ligament injuries of the knee. Knee Surg Sports Traumatol Arthrosc 1998;6(1): 21-25.
10. Kannus P: Nonoperative treatment of grade II and III sprains of the lateral ligament compartment of the knee. Am J Sports Med 1989;17(1):83-88.
11. Bushnell, Brandon D., et al. “Treatment of magnetic resonance imaging-documented isolated grade III lateral collateral ligament injuries in National Football League athletes.” The American journal of sports medicine 38.1 (2010): 86-91.
12. Geeslin AG, LaPrade RF (2011) Outcomes of treatment of acute grade-III isolated and combined posterolateral knee injuries: a prospective case series and surgical technique. J Bone Joint Surg Am 93:1672–1683
13. Coobs BR, LaPrade RF, Griffith CJ, Nelson BJ (2007) Biomechanical analysis of an isolated fibular (lateral) collateral ligament reconstruction using an autogenous semitendinosus graft. Am J Sports Med 35(9):1521–1527
14. LaPrade RF, Spiridonov SI, Coobs BR, Ruckert PR, Griffith CJ (2010) Fibular collateral ligament anatomical reconstructions: a prospective outcomes study. Am J Sports Med 38(10):2005–2011
15. Moulton SG, Matheny LM, James EW, LaPrade RF. Outcomes following anatomic fibular (lateral) collateral ligament reconstruction. Knee Surg Sports Traumatol Arthrosc. 2015 Oct;23(10):2960-6