Medial Collateral Knee Ligament Injury
- Author: Thomas M DeBerardino, MD; Chief Editor: Craig C Young, MD more...
Background
Medial collateral ligament (MCL) injuries of the knee are very common sports-related injuries. The MCL is the most commonly injured knee ligament. Injuries to the MCL occur in almost all sports and in all age groups.
Epidemiology
Frequency
United States
The incidence of MCL injuries is impossible to determine because of the wide spectrum of injury severity. Many MCL injuries are minor and may never be evaluated by a physician.[1]
Functional Anatomy
The medial aspect of the knee has been divided into 3 distinct layers based on cadaver dissection. The first layer is the deep fascia, which consists of the sartorius fascia anteriorly and a thin fascial layer posteriorly. The thin posterior fascia covers the popliteal fossa and the heads of the gastrocnemius muscle. The second layer includes the superficial MCL, also known as the tibial collateral ligament. This ligament attaches proximally to the medial femoral epicondyle and to the tibia distally, approximately 4-5 cm distal to the joint line. The parapatellar retinaculum and patellofemoral ligament are within this layer.
The third layer is the knee joint capsule, which attaches proximally and distally at the articular margins. The capsule is divided into thirds from anterior to posterior. The anterior third of the capsule is the thinnest portion. It is attached to the anterior horn of the medial meniscus and is reinforced by the medial retinaculum. The middle third of the capsule consists of the deep medial collateral ligament. It is firmly attached to the mid body of the medial meniscus. Proximal to the meniscal attachment, it is termed the meniscofemoral ligament. Distal to its meniscal attachment, it is termed the meniscotibial ligament. The posterior third of the capsule includes the posterior oblique ligament (POL) and the oblique popliteal ligament. The POL has 3 arms, the superficial, tibial, and capsular.
Sport Specific Biomechanics
The superficial MCL has been shown through serial cutting studies to provide the primary restraint to valgus loads at all degrees of flexion. It is also an important restraint to anterior tibial translation when the anterior cruciate ligament is injured. The superficial MCL acts as a primary restraint to external rotation of the tibia.
Stability of the medial side of the knee is provided by dynamic and static restraints. The static restraints are the superficial MCL and the joint capsule, including the deep MCL and the POL. The semimembranosus muscle, the pes anserine muscles, and the vastus medialis muscle provide dynamic stability. The muscles of the pes include the sartorius, gracilis, and semitendinosus. These muscles flex and internally rotate the tibia. The semimembranosus has 4 attachments: direct, tibial, inferior, and capsular.[2, 3]
Chahal J, Al-Taki M, Pearce D, et al. Injury patterns to the posteromedial corner of the knee in high-grade multiligament knee injuries: a MRI study. Knee Surg Sports Traumatol Arthrosc. Dec 15 2009;[Medline].
Griffith CJ, LaPrade RF, Johansen S, et al. Medial knee injury: part 1, static function of the individual components of the main medial knee structures. Am J Sports Med. Sep 2009;37(9):1762-70. [Medline].
Wijdicks CA, Griffith CJ, LaPrade RF, et al. Medial knee injury: part 2, load sharing between the posterior oblique ligament and superficial medial collateral ligament. Am J Sports Med. Sep 2009;37(9):1771-6. [Medline].
Laprade RF, Bernhardson AS, Griffith CJ, et al. Correlation of valgus stress radiographs with medial knee ligament injuries: an in vitro biomechanical study. Am J Sports Med. Dec 4 2009;[Medline].
Laprade RF, Bernhardson AS, Griffith CJ, Macalena JA, Wijdicks CA. Correlation of valgus stress radiographs with medial knee ligament injuries: an in vitro biomechanical study. Am J Sports Med. Feb 2010;38(2):330-8. [Medline].
Lind M, Jakobsen BW, Lund B, et al. Anatomical reconstruction of the medial collateral ligament and posteromedial corner of the knee in patients with chronic medial collateral ligament instability. Am J Sports Med. Jun 2009;37(6):1116-22. [Medline].
Albright JP, Powell JW, Smith W, et al. Medial collateral ligament knee sprains in college football. Effectiveness of preventive braces. Am J Sports Med. Jan-Feb 1994;22(1):12-8. [Medline].
Fanelli GC, Edson CJ, Orcutt DR, et al. Treatment of combined anterior cruciate-posterior cruciate ligament-medial-lateral side knee injuries. J Knee Surg. Jul 2005;18(3):240-8. [Medline].
Halinen J, Lindahl J, Hirvensalo E, Santavirta S. Operative and Nonoperative Treatments of Medial Collateral Ligament Rupture With Early Anterior Cruciate Ligament Reconstruction: A Prospective Randomized Study. Am J Sports Med. Feb 1 2006.
Lundberg M, Messner K. Long-term prognosis of isolated partial medial collateral ligament ruptures. A ten-year clinical and radiographic evaluation of a prospectively observed group of patients. Am J Sports Med. Mar-Apr 1996;24(2):160-3. [Medline].
Lundberg M, Messner K. Ten-year prognosis of isolated and combined medial collateral ligament ruptures. A matched comparison in 40 patients using clinical and radiographic evaluations. Am J Sports Med. Jan-Feb 1997;25(1):2-6. [Medline].
Reider B. Medial collateral ligament injuries in athletes. Sports Med. Feb 1996;21(2):147-56. [Medline].
Reider B, Sathy MR, Talkington J, et al. Treatment of isolated medial collateral ligament injuries in athletes with early functional rehabilitation. A five-year follow-up study. Am J Sports Med. Jul-Aug 1994;22(4):470-7. [Medline].
Warren LF, Marshall JL. The supporting structures and layers on the medial side of the knee: an anatomical analysis. J Bone Joint Surg Am. Jan 1979;61(1):56-62. [Medline].
Print
