Medial Collateral Ligament Injury of the Knee

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Definition/Description

A medial collateral ligament (MCL) injury is a torn, partial tear, or complete tear of the ligament on the inside of the knee. The MCL is one of the most frequently injured knee structure. The anatomy and biomechanical role of this
ligament and the associated posteromedial structures of the knee
continue to be explored. It is usually injured because of valgus forces applied to the knee.

Clinically Relevant Anatomy 

The medial collateral ligament, also called the tibial collateral ligament, is a ligament made of tough fibrous material, functions to control excessive motion by limiting the joint mobility. The medial collateral ligament (MCL) is one of the four ligaments that are critical to maintain the stability of the knee joint. The four major ligaments of the knee-area are the cruciate ligaments (anterior and posterior), and the collateral ligaments (medial and lateral). Proximally the MCL attaches to the medial femoral condyle and distally it attaches to the metaphyseal area of the tibia. The MCL is the main medial stabilizer. , it guides intra-articular movement (for example: roll, spin, slip and translation).

Epidemiology /Etiology

MCL injuries mostly occur after an impact on the outside of the knee. The causes of this injury are often a valgus trauma (contact/noncontact) or external tibial rotation.   The MCL on the inside of the knee becomes stretched. When the force of the impact is big enough, some or all the fibers will tear. Mostly the deep part of the ligament gets damaged first and this may lead to medial meniscal damage or anterior cruciate ligament damage. A major MCL injury may be caused by a lateral push to the lower thigh or upper leg. For example The MCL injury can appear in football from a tackle or block against the lateral aspect of the knee, a skier can also get injured to his MCL. The pathology of an MCL injury is limited to the proximal or the distal ends of the ligament. 

Characteristics/Clinical Presentation

As with all the ligament injuries, the MCL injury is graded 1, 2 or 3 (this grade is given depending on the degree of sustained) . A grade 1 tear consists of less than 10% of the collagen fibres being torn. Grade 2 tears vary in symptoms and therefore they are broken down further to grades 2- (closer to grade 1) and 2+ closer to grade 3). Obviously, this means that a grade 3 tear is a complete rupture of the MCL.
The symptoms for a grade 1 tear of the MCL are minimal. Patients complain about a mild tenderness on the inside of the knee. Usually we can’t detect a swelling over the ligament or joint laxity. Most of the patients feel pain when we apply force on the outside of a slightly bent knee.

Grade 2 injuries are also considered as incomplete tears of the MCL. Patients with a grade 2 tear mostly complain about instability when attempting to cut or pivot. The pain and swelling are more significant than with grade 1 injuries. When the knee is stressed (as for grade 1), patients complain about pain, moderate laxity in the joint and a significant tenderness on the inside of the knee.
When we speak of a grade 3 tear of the MCL, it is considered as a complete rupture of the ligament. Patients have significant pain and swelling over the MCL. Most of the time they have difficulty bending the knee. Another common finding of a grade 3 tear is instability. When we stress the knee (as described above) there is joint laxity.

Differential Diagnosis

Differential diagnosis is necessary to exclude injuries that may cause the same symptoms as MCL injury of the knee. These injuries are:

• Medial meniscal tear/injury
  
• Anterior cruciate ligament (ACL) tear
  
• Tibial plateau fracture
  
• Femur injury or fracture
  
• Patellar subluxation/dislocation
  
• Medial knee contusion
  
• Pediatric distal femoral fracture
  
• Damage to the posteromedial corner structures
  
  

A physical examination will help to ensure a correct diagnosis. A medial meniscal tear can be mistaken for an MCL sprain, because the tear causes joint tenderness like the sprain. With a valgus laxity examination a medial meniscal tear can be differentiated from a grade 2 or 3 MCL sprain. The presence of an opening on the joint line means the medial meniscus is torn. A grade 1 MCL is more difficult to differentiate from a medial meniscal tear. The differentiation can be made through an MRI or by observing the patient during several weeks. In case of an MCL sprain tenderness usually resolves, with a meniscal injury it persists.

When there is tenderness, but no abnormal valgus laxity, it could be a case of medial knee contusion. If the tenderness is situated near the adductor tubercle or medial retinaculum adjacent to the patella, the cause is more likely to be patellar dislocation or subluxation. Patellar instability can be differentiated from an MCL sprain with the patellar apprehension test. A positive result means there is patellar instability.  

If the patient is a child, a gentle stress-testing radiograph can determine if they have a distal femoral fracture instead of an MCL sprain. 

Diagnostic Procedures

MCL valgus stress test

Outcome Measures

A committee of international knee experts created the International Knee Documentation Committee Subjective Knee Form (IKDC-SKF), which is a knee-specific, rather than a disease-specific, measure of symptoms, function, and sports activity. IKDC-SKF is a reliable and valid knee-specific measure of symptoms, function, and sports activity that is appropriate for patients with a wide variety of knee problems. Outcome is related to the severity of the injury and the functional rehabilitation possible.

International Knee Documentation Committee Subjective Knee Form

Examination

add text here related to physical examination and assessment

Medical Management

Some surgeons describe a grade four injury to the MCL. This is called a medial column injury. It involves a more complex injury with different ligaments than just the MCL.

Some doctors prefer that all MCL injuries are healed without surgery, and others prefer to repair these most significant injuries. No difference has been demonstrated between both treatments.

Physical Therapy Management

The treatment of a medial collateral ligament injury rarely requires a surgical intervention. Some simple treatment steps, together with rehabilitation, will allow patients to return to their previous level of activity. The main goals of the rehabilitation are : reducing pain and swelling, restoring full mobility, improving strength and stability of the joint and returning to full activity. 

Grade 1

A grade 1 injury-treatment can be divided into three phases.

Phase one (first week after injuring) consists of reducing the swelling by applying cold therapy (1) and a compression. The first day after injuring the patient needs to apply ice for 15 minutes every two hours. This frequency can gradually be reduced to three times a day (remember that ice burns, so do not apply ice directly to the skin). As soon as pain allows, the patient can start with some stretching exercises for hamstring- and quadriceps-muscles and light static strengthening exercises (After each stretch/strengthening session, make sure the patient applies cold therapy).

After a week we can start with phase two of the rehabilitation. At this phase we will try to eliminate any swelling completely and regain full range of motion. The patient still needs to train itself with the strength- and stretch exercises from phase one (after each session, apply cold therapy). He can return to jog or cycle slowly, to maintain aerobic fitness (as long as it is not painful). We can introduce dynamic strengthening exercises to each strengthening-session ( knee extension/flexion, half squats, step ups, … ). Deep friction massage can be added ( on alternate days ).

The third phase (after two weeks) consists of maintaining full range of motion, equaling strength of both legs and returning to running. The patient continues the stretch- and strengthening-sessions (after each session, apply cold therapy). Building on the dynamic strengthening exercises is one of the major goals of this phase. The intensity and number of repetitions ( between 10 and 20 reps) need to be increased until the strength of both legs is equal.

Grade 2/3

For a grade 2/3 injury-treatment it is important that the ends of the ligament are protected and left to heal without continually being disrupted. The rehabilitation can be split into 3 phases.

Phase one consists of controlling the swelling of the knee by applying ice for 15 minutes every two hours (first two days). The rest of the week the frequency can be reduced to three times a day. Another aim of this phase is trying to maintain the ability to straighten and bend the knee more than 90°. Pain free stretches for the hamstrings, quads, groin and calf muscles (in particular) are suggested. The patient may begin with static strengthening exercises (as soon as pain allows it), such as quads and double leg calf raises. It’s important that the patient rests from all painful activities (use crutches if necessary), and that the MCL is well protected (by wearing a stabilized knee brace). After four weeks we can start phase two. Major goal for this phase : full weight-bearing on the injured knee. Dynamic strengthening exercises as knee flexion/extension, half squats and hip raises may benefit progression. We continue with cold therapy and compression to eliminate swelling. To maintain aerobic fitness the patient can use the stepper or (if possible) may begin to swim. Six weeks after injuring the knee, phase three can begin. Cold therapy still needs to be applied. The intensity of the strengthening exercises need to be increased and instead of double leg exercises we change to single leg exercises. The patient may start running again at a comfortable pace (make sure the patient doesn’t make sudden changes of direction).

(1) Applying cold therapy reduces swelling immediately after injuring and doesn’t help the healing process of the ligament.

Key Research

1. Irrgang JJ, Fitzgerald GK ( 2000 ),Rehabilitation of the multiple-ligament-injured knee
2. Yastrebov O., Lobenhoffer P. ( 2009 ), Treatment of isolated and multiple ligament injuries of the knee: anatomy, biomechanics, diagnosis, indications for repair, surgery
3. Swenson TM (2000), Physical diagnosis of the multiple-ligament-injured knee
4. Scheidt DK (2003), Treatment of the multiple ligament injured knee and dislocations : a trauma perspective
   

Resources

1. Roald Bahr – Sverre Maehlum- Tommy Bolic (2002), Clinical guide to sports injuries : an illustrated guide to the management of injuries in physical activity, p. 321-324 + p.328-329
2. Paul K. Canavan (1998), Rehabilitation in sports medecine : a comprehensive guide, p. 293-295 + p. 301-304
3. Patrick J. – Macmahon MD (2007), Current diagnosis and treatment in sports medecine, p. 77-82
4. Francis A. Burgener (2006), Differential diagnosis in magnetic resonance imaging, p.396
5. David E. Brown – Randall D. Neumann (2004), Orthopedic secrets, p. 328-332
6.  
   
   

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