One of the most common sports-related knee injuries is medial collateral ligament (MCL), which occurs in almost every contact sport, such as football, hockey, wrestling, and martial arts. Those more at risk are intercollegiate male athletes, who can experience mild MCL sprain that could keep them away from exercising sports for an average of three weeks (DeBerardino, 2014). However, the severity of the injury has a broad spectrum, it is impossible to determine the incidence of MCL injuries, especially since minor MCL injuries are never evaluated by a physician.
Anatomy of the Injury (structures involved)
One of the most commonly injured knee-joint ligamentous structures is the medial collateral ligament. The medial knee has structures regarded as static stabilizers, which are the superficial medial collateral ligament, the deep medial collateral ligament, and the posterior oblique ligament (Phisitkul et. al., 2006). The fundamental static stabilizer of the knee is the superficial medial collateral ligament, and is the second of the knee’s three distinct layers, positioned between the deep medial collateral ligament and the superficial sartorial fascia. From the center of knee motion, there originate three parallel fibers “on the medial femoral epicondyle and insert on the medial aspect of the proximal tibia five to seven centimeters (cm) below the joint line, with an average length of 11 cm and an average width of 1.5 cm” (Phisitkul et. al., 2006). The ligament is positioned superficially to the deep medial collateral ligament and deep into the sartorial fascia and the crural. Between the confluence of the first two layers and the superficial medial collateral ligament, lies a split that is vertical and varies in shape and size (Phisitkul et. al., 2006).
Figure 1: Cadaver Dissection- The two white triangles show the slit in the superficial MCL. The posterior oblique ligament is in continuity with the superficial MLC posteriorly’s parallel fibers. The ligament inserts about 7cm below the joint line.
Taken from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1888587/#!po=9.61538
The ligament’s posterior aspect has oblique fibers that are called posterior oblique ligament and form a structure that has come from the conjoined second and third layers, shaping the posteromedial capsule (Phisitkul et. al., 2006). The posterior oblique ligament has three attachments; (1) the inferior arm, (2) the prominent tribial, and (3) the capsular arm. The third part of the middle capsular ligament, or also known as the medial capsule, is a thick and deep medial collateral ligament, and lies in the deepest (third) layer, inserting below the tibial articular margin. Although study have failed to demonstrate that both the posterior oblique ligament and the deep medial collateral ligament had any significant contribution to stability, it is believed that the posterior oblique ligament is an exceptional assistant to the semimembranosus tendon’s dynamic function (Phisitkul et. al., 2006). The medial side of the knee has three dynamic stabilizers, (1) the semimembranosus complex, (2) the pes anserinus, and (3) the quadriceps. The semimembranosus tendon plays an essential role in the dynamic stability of the medial part of the knee, as it helps prevent impingement during knee flexion, by displacing the medial meniscus’ posterior horn while tightening the lax posterior oblique ligament (Phisitkul et. al., 2006). The pes anserinus and the quadriceps are believed to enhance the knee medial collateral ligament’s stiffness by 108 percent and 164 percent respectively. Nevertheless, these muscles have a very low reaction time, which is not enough to provide protection against most sports-related injuries (Phisitkul et. al., 2006).
Mechanism of Injury
Generally, there are two ways to obtain the mechanism of injury: (1) by taking a thorough history, or (2) from direct observation of the injury. The most common mechanism of injury is valgus stress; but, because of the position of the force vectors and the knee, it usually is a combined injury that includes valgus, flexion, and rotation injury that leads to medial collateral ligament strain (Phisitkul et al, 2006).
Usually, medial collateral ligament sprain may occur from a contact injury (e.g. playing football and clipping from the lateral side), or from a noncontact involvement, such as in skiing. In the later situation, the inside of the knee may force valgus to an external rotation (Hammer, 2007 p.363). In other words, the most common MCL injuries in skiing include valgus external rotation of a noncontact nature. However, the devastating majority of MCL injuries are the outcome of a direct blow to the upper leg’s or lower thigh’s outer aspect (Phisitkul et al, 2006). That being said; the most common injury of a noncontact nature is a combination of valgus, deceleration, and external rotation of the leg. Other mechanisms of the injury include straight medial opening of the valgus, straight lateral opening of the valgus, varus internal and/or external rotation, hyperextension, and direct blow that drives the tibia backwards or forward (Hammer, 2007 p.363). Usually, the menisci do not tear due to a valgus force, because it takes shear forces and compression to accomplish that. A detached meniscus can occur when the meniscotibial ligament tears. The medial knee may take hours before it causes annoyance, and a clip to the external of the knee may cause pain only on the lateral knee (Hammer, 2007 p.363). When ligament tears, the patient’s age plays a significant role to the type of injury. For example, an individual between 10 and 16 years old, may experience a separation of the distal femoral epiphysis, because the growth plate is weaker than the ligament, in a clipping type of trauma, either to the posterolateral or lateral part of a flexed knee (Hammer, 2007 p.363). On the other hand, an individual between 16 and 40 years of age, is more likely to experience an anterior cruciate ligament or medial collateral tear.
Having said that; the clinical history can provide valuable information, such as the time and onset of swelling, the location of the pain, the sensation of a tear or pop, the ability to walk after the injury, whether a deformity is present, and the exact tender site (Phisitkul et al, 2006). If there is no obvious swelling, this could indicate a much more serious condition with a possible tear that allows fluid to run in the tissue surrounding the joint. If there is severe effusion in the two first hours after the injury, then hemarthrosis occurs, while if swelling is obvious 12-24 hours after the injury, the patient might be experiencing synovial effusion (Phisitkul et al, 2006). Three quarters of patients with complete medial collateral ligament tears were able to walk without any help or support. As for pain, it is reported to be worse when the patient experiences incomplete, rather than complete, tears.
Levels of Injury
When diagnosed with a Grade II and III medial collateral ligament sprain, the injury is either incomplete or complete rupture of the collagen fibers that connect the end of the thigh bone (femur) and the shin bone (tibia) respectively (Figure 2) (Rosenberg Cooley Metcalf, n.d). Grade II and III MCL sprains usually occur due to a fall, or excessive strain applied to the knee’s stabilized ligament during sports. Symptomatology includes pain and tenderness, as well as weakness and swelling in the area around the knee’s medial aspect ((Rosenberg Cooley Metcalf, n.d).
Figure 2: Knee’s Side View that shows Grade II or II medial collateral ligament sprain.
Taken from: http://www.rcmclinic.com/patient-info/knee/diagnosis/59-knee-diagnosis/85-grade-ii-or-iii-mcl-sprain
Treatment options of applicable and return to play
Two of the most widely used treatment options, after diagnosis has been made through either radiography or magnetic resonance imaging, are physical therapy and surgery. Sprains falling under the Grade I and II category are usually treated without the need to surgery. Sprains are initially treated by following the RICE protocol, according to which, rest, ice, compression, and elevation is the suggested process (DeBerardino, 2014). Until normal gait is acquired, weight bearing is established with the use of crutches for a few days. However, the severity of the injuries will be the only indicator as to whether further treatment is required. Incomplete tears have a speedy recovery and individuals get back to their activities in a timely manner.
Almost all Grade III tears need an operative treatment; however, in recent times, they can also be treated with others means, nonoperative, most often with a long leg cast (DeBerardino, 2014). That being said; some authors also recommend bracing with a hinged knee orthosis, a waiting period of up to 6 weeks with the knee flexed at 30°, or immediate braced rise in range of motion, and crutches necessary for up to half a month (DeBerardino, 2014).
The target of the therapy is to help reduce the pain, regain strength, and restore range of motion, and crutches are used until the individual can bear their own weight without experiencing discomfort. Additionally, range of motion exercises, quad sets, running up to the point of pivoting, and sport-specific exercises are performed gradually. It normally takes up to three weeks for Individuals with Grade I and II injuries to return to play, while those with Grade III injuries require up to six weeks, or even more (DeBerardino, 2014).
Then, the therapist concentrates on controlled strengthening, after range in motion is restored, and sufficient ligament healing has occurred. Afterwards the athlete must go through a function-based or sport-based training, and, when pain is significantly reduced, and full strength is achieved, the athlete can return to their sport, without any external support or brace (DeBerardino, 2014).
Reconstruction is required with ruptures of the PLC, ACL, and MCL, while surgery is also necessary when the individual has persistent instability and needs tissue repair. However, studies have found that both operative and nonoperative treatments of medial collateral ligament injuries have satisfactory results (DeBerardino, 2014).
Conclusion
Medial collateral ligament sprain is a common injury among athletes of both contact and noncontact sports. There are three levels of injury, from Grade I to Grade III, depending on the severity of the injury, which require a healing/rehabilitation period of a few weeks to almost two months. An athlete could either experience a complete rupture of the connective collagen fibers, or an incomplete rupture and would need surgery to heal or physical therapy with a series of carefully structured workouts that would eventually lead the individual to comfortable weight bearing and pain relief.
References:
DeBerardino, Thomas (2014), Medial Collateral Knee Ligament Injury Clinical Presentation. Medscape. Retrieved June 13, 2014 from: http://emedicine.medscape.com/article/89890-clinical#a0218
Hammer, Warren (2007), Functional Soft-tissue Examination and Treatment by Manual Methods. Jones & Bartlett Learning. ISBN 0763733105.
Phisitkul, Phinit (2006), MCL Injuries of the Knee: Current Concepts Review. Iowa Orthopaedic Journal 2006; 26: 77-90. Retrieved June 13, 2014 from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1888587/#!po=9.61538
Rosenberg Cooley Metcalf (n.d), Grade II or Grade III Sprain of the Medial Collateral Ligament (MCL). The Orthopaedic Clinic at Park City. Retrieved June 13, 2014 from: http://www.rcmclinic.com/patient-info/knee/diagnosis/59-knee-diagnosis/85-grade-ii-or-iii-mcl-sprain
