The medial collateral ligament (MCL) and lateral collateral ligament (LCL) serve as mediolateral stabilizers of the knee and provide some degree of rotational stability. Injury to the ligament(s) occurs when external forces applied to the knee overwhelm the integrity of the ligament(s), either in isolation or in combination with other structures (i.e., other ligaments, bone, or menisci).
MCL sprains occur as a result of an excessive valgus load and/or external tibial rotation. Isolated LCL sprains result from an excessive varus load to the knee. These injuries typically occur in contact and collision sports (football and soccer) or in sports where high torque forces can be generated about the knee (i.e., skiing and ice skating).
Epidemiology including risk factors and primary prevention
Ligament sprains are the most common type of knee injury.1 The MCL and ACL are the most commonly sprained knee ligaments. The MCL is injured in at least 42% of knee ligament injuries, with isolated MCL injuries accounting for 29% of ligamentous knee injuries alone.1 In the U.S. population, the incidence of MCL injury is 0.24/1000 people or 74,000 injuries annually.2 In young athletes, females were found to have a higher rate of MCL injury in high school, while the relationship reversed in college athletes.3 MCL sprain is the most common knee injury in high school athletes. Skiing (60% of skiing-related injuries) accounts for a large percentage of these injuries. MCL injuries are also commonly seen in contact sports such as American football, soccer, hockey and rugby. In a cohort study of athletes with isolated MCL sprains, the average amount of time lost per injury was 23.2 days.4
MCL injuries are more common than LCL injuries. Isolated LCL injuries are rare, accounting for only 2% of knee ligament injuries.1 LCL injuries are more commonly associated with a more profound injury to the knee involving the posterolateral corner structures.
Knee collateral ligament injury prevention has been studied in American football players. Hinged knee braces have been found to help reduce the rate of MCL injuries in American football linemen, linebackers, and tight ends.5
The MCL is composed of a superficial and a deep layer. The superficial layer runs from just posterior to the medial femoral epicondyle down 6 cm beyond the medial tibial plateau. The deep layer is a thickening of the joint capsule itself; it is composed of the meniscofemoral and meniscotibial components. Isolated MCL injuries typically involve the proximal fibers of the superficial layer. The MCL is extraarticular; thus, in isolated MCL injuries, medial knee swelling may occur, but intraarticular effusion will be absent.
The LCL starts proximally just posterior to the lateral femoral condyle and attaches distally to the proximal portion of the fibula in a conjoined fashion with the biceps femoris tendon. Isolated LCL sprains occur as a result of excessive varus loading of the knee. Avulsion of the LCL off the fibula usually signifies a concomitant posterolateral corner injury.
Collateral ligament sprains are graded:
- Grade 1: pain along ligament, no instability or gapping of joint with stress testing
- Grade 2: partial gapping (5-10 mm) of joint with stress testing at 30 degrees of knee flexion
- Grade 3: wide gapping (>10 mm) of joint at 30 degrees of knee flexion (no end feel).
Disease progression including natural history, disease phases or stages, disease trajectory (clinical features and presentation over time)
The natural history of an isolated medial or lateral collateral ligament injury is good and both can generally be treated non-operatively. Initially the knee may be swollen and painful, which may limit range of motion. The quadriceps muscle may become inhibited secondary to pain and swelling. During the sub-acute phase, pain and swelling resolve and ligamentous laxity improves. Progression through the rehabilitation process will parallel these improvements. Return to play can be estimated as follows: grade 1 (approx. 10 days), grade 2 (approx. 20 days), grade 3 (approx. 60 days).6
Specific secondary or associated conditions and complications
Collateral ligament injuries can be associated with cruciate ligament sprains, meniscal tears, capsular avulsion injuries, fractures or bony contusions, patellar dislocations and complex multi-structure injuries occurring along the corners of the knee. Combined injuries may require operative repair to stabilize the knee. Failure to recognize these more complex injuries can lead to chronic instability, repeated soft tissue injury and ultimately post-traumatic arthritis.
2. ESSENTIALS OF ASSESSMENT
- Mechanism of injury: Did the injury occur with twisting or cutting or with a blow? Location of impact?
- Ability to continue with participation in activity immediately after injury
- Location of swelling and/or bruising and time course of swelling.
- Exacerbating and alleviating factors
- Mechanical symptoms, such as instability or a locked joint
- Neurovascular symptoms
- Observation and inspection of joint for obvious deformity
- Inspection and palpation of joint: assess effusion and tenderness
- Active and passive range of motion of hip, knee, and ankle
- Valgus and varus stress testing of the knee at 30 degrees to isolate stress to collateral ligaments
- grade 1 injury: firm end feel
- grade 2 injury: firm end feel with minor opening of joint
- grade 3 injury: soft/no end feel with significant opening of joint
- Valgus and varus stress testing at 0 degrees: lack of a firm end feel in this position indicates injury to the collateral ligament plus additional ligamentous structures such as cruciate ligament or corner injury.
- Neurologic and vascular examination of lower extremities
- Gait: ability to bear weight
Ambulation may be limited secondary to pain and swelling. The patient may also report knee instability with ambulation. As the condition improves, the range of motion and gait normalize.
Radiographs (A-P, lateral, and sunrise views) are generally ordered to assess for fractures. Stress radiographs are completed with valgus stress at 20 degrees of flexion and can elucidate more severe injury:7
- > 3.2mm gapping = grade 3 superficial MCL tear
- > 9.8mm gapping = complete tear of both MCL layers and the posterior oblique ligament
Others have suggested utilizing the Ottawa knee rules to guide the decision to obtain radiographs in a suspected MCL/LCL injury. According to these rules, a radiographic knee series is only indicated if one or more of the five criteria below are met.8
- Patient age ≥ 55 years
- Isolated tenderness of the patella
- Tenderness at the head of the fibula
- Inability to flex knee to 90o
- Inability to bear weight both immediately and in the emergency department for 4 steps.
MRI has an 86.4 % sensitivity and accuracy in identifying an MCL injury; however, MRI is generally not necessary unless there is concern for associated injuries or surgical repair is being considered.9
Ultrasonography is a quick and cost effective way to assess the collateral ligaments. Under direct visualization the ligaments can be stressed at 30 degrees of knee flexion. Medial joint line opening can be objectively measured to aid in grading the injury: 0-5mm of opening = grade 1; 5-10mm = grade 2; > 10mm = grade 3.10
Supplemental assessment tools
Utilizing functional measures of the knee can assist with deciding if the knee has fully recovered, but these functional measures are only validated for post-ACL rehabilitation.
Early predictions of outcomes
Isolated collateral ligament injuries generally have a good natural history with non-operative management, allowing for full return to participation in the majority of cases. Lower grade injuries are associated with quicker recovery periods. Multi-structure injuries may warrant additional investigative studies (i.e., MRI) and potential need for operative intervention.
Although most medial collateral ligament injuries are treated non-operatively, it is important to be aware of special situations involving compete disruption that may require operative intervention. Indications for operative treatment include:11
- A large bony avulsion
- A concomitant tibial plateau fracture
- Associated cruciate ligament injury
- Intra-articular entrapment of the end of ligament.
Collateral ligament injuries typically occur in contact and collision sports such as American football, soccer, and ice hockey where the participant is vulnerable to sudden unexpected blows to the knee. Sports such as skiing may expose the knee to excessive rotation forces, injuring portions of the MCL.
Social role and social support system
Isolated collateral ligament injuries rarely result in long-term disability. If chronic instability and pain result, the patient may not be able to resume prior level of sports/activity or employment. In these instances, referral to psychology for adjustment and/or vocational rehabilitation may be warranted.
Isolated knee collateral ligament injuries generally heal with non-operative management over a course of weeks to months. During the recovery period the patient will need to be removed from the offending activity to allow the ligament to adequately heal. Length of recovery is generally related to the severity of the ligament injury.
3. REHABILITATION MANAGEMENT AND TREATMENTS
Available or current treatment guidelines
Acute injuries are generally managed with weight bearing as tolerated. Bracing of the joint maybe performed initially, depending on degree of instability or presence of valgus/varus angulation of knee joint. P.R.I.C.E (Protect, Rest, Ice, Compression, Elevation) principles are employed initially along with early restoration of joint motion.
Quadriceps and hamstring strengthening exercises are progressed from isometric to open chain isotonic exercises as tolerated, aerobic exercise is resumed as soon as tolerated. Once pain is reduced and strength is 80% of the contralateral side, closed chain strengthening exercises are initiated. As joint stability normalizes, neuromuscular/agility training is initiated in preparation for return to play/activity.6
At different disease stages
Isolated collateral ligament injuries regardless of grade generally heal and patients can expect to resume prior level of activity. Questions still remain regarding the need for bracing upon return to sports/activity. Studies reveal that off-the-shelf knee braces can reduce loading of the MCL and rate of injury among certain positions in football.4 Patients with ongoing pain, swelling or mechanical symptoms may have associated injuries such as meniscal tear(s) or other ligamentous injuries. These cases may warrant further evaluation to identify the source(s) of their ongoing impairment. In the case of an acute multi-ligament injured knee or a chronically unstable knee with persistent medial laxity, surgical repair of the collateral ligament(s) may be indicated. For multi-ligament injuries involving both the ACL and MCL, early ACL reconstruction and MCL repair are recommended when there is increased medial joint space opening with valgus stress in extension, a significant meniscotibial deep MCL injury, or a displaced tibial-sided superficial MCL avulsion.12
Coordination of care
A detailed rehabilitation protocol should be developed and effectively communicated to the treating physical therapist or athletic trainer. Follow-up visits with the patient should occur during transition periods within the protocol to ensure that the patient is progressing as expected.
Patient & family education
The patient and family should be advised that the natural history of isolated collateral ligament(s) injury is good. However, premature resumption of sports/activity may stress the healing ligament too soon and lead to chronic instability and pain. The patient should return to sports when laxity has resolved and they can perform sport/activity specific maneuvers without pain or instability.
Patient outcomes can be measured with the Tegner Lysholm Knee Scoring Scale. This scoring system assesses pain, instability symptoms, and functional limitations.13 This measurement outcome can be used clinically or for research purposes. Return to play/activity is empirically driven and based on reduction in pain, resolution of ligamentous laxity, and presence of full joint range of motion and strength. Functional assessment prior to returning an athlete to play should be performed by a physical therapist and/or athletic trainer to ensure sport/activity-related maneuvers can be performed without pain and instability.
Translation into practice: practice “pearls”/performance improvement in practice (PIPs)/changes in clinical practice behaviors and skills
Early initiation of a rehabilitation protocol focusing on restoration of motion, weight bearing as tolerated, and a graduated strength and condition program lead to more efficient recovery and return to sport/activity. Newer animal studies show evidence that NSAIDs may impair the healing of ligamentous tissue; as a result, one should consider limited use of these medications.14
4. CUTTING EDGE/EMERGING AND UNIQUE CONCEPTS AND PRACTICE
Cutting edge concepts and practice
Prolotherapy or proliferative therapy has been used to enhance healing of ligamentous structures through the direct injection of substances into an injured ligament. Substances used include dextrose, sarapin, procaine, and lidocaine as well as protein-rich plasma (PRP) and autologous stem cells. PRP studies in animal models have shown mixed results with regards to early MCL injury healing over the first three to six weeks post-injury.15,16Clinical studies using PRP for ligament injuries have shown some positive outcomes including improved pain and function.17 In one case report, a football player with an isolated Grade III MCL injury received three injections of L-PRP with 1-week intervals and was followed for 16 months. The football player resumed sports activities at day 18, and full competition at day 25.18Another case study using prolotherapy treatment showed improvement in a rugby player’s grade 2 MCL sprain in just 3 weeks, at which time he was pain free and with full range of motion. Injections of 15% dextrose and 0.2% lidocaine were used. This three-week recovery was compared to a typical four to eight week recovery for MCL sprain.19 The quality of available evidence is insufficient to guide clinical decisions about PRP administration in MCL/LCL injuries of the knee due to the paucity of controlled clinical studies.
As diagnostic ultrasound become more accessible in the clinic and training room setting, a more precise evaluation of the ligamentous injury can take place.
5.GAPS IN THE EVIDENCE-BASED KNOWLEDGE
Gaps in the evidence-based knowledge
- Can braces be developed that protect against knee injuries?
- Can exercise interventions and educational programs reduce the rate of knee injuries?
- Is there a role for regenerative therapies in the treatment of ligament injuries?
- Is reconstruction of the MCL necessary in the treatment of a multiligament knee injury?
- Bollen S. Epidemiology of knee injuries: diagnosis and triage. Br J Sports Med. 2000;34(3):227-228. doi:10.1136/bjsm.34.3.227-a.
- Daniel DM, Pedowitz RA, OConnor JJ, and Akeson WH. Daniel’s Knee Injuries: Ligament and Cartilage Structure, Function, Injury, and Repair. 2nd ed. Lippincott WIlliams & Wilkins; 2003.
- Stanley LE, Kerr ZY, Dompier TP, and Padua DA. Sex differences in the incidence of anterior cruciate ligament, medial collateral ligament, and meniscal injuries in collegiate and high school sports: 2009-2010 through 2013-2014. Am J Sports Med. March 2016:0363546516630927. doi:10.1177/0363546516630927.
- Roach CJ, Haley CA, Cameron KL, Pallis M, Svoboda SJ, and Owens BD. The epidemiology of medial collateral ligament sprains in young athletes. American Journal of Sports Medicine. 2014; 42(5): 1103-1109. doi:10.1177/0363546514524524.
- Najibi S. The use of knee braces, Part 1: prophylactic knee braces in contact sports. American Journal of Sports Medicine. 2005; 33(4): 602-611. doi:10.1177/0363546505275128.
- Delee J, Drez D, and Miller M. Orthopedic Sports Medicine: Principles and Practice. Philadelphia, PA: Saunders; 2010:1624-1637.
- LaPrade RF, Bernhardson AS, Griffith CJ, Macalena JA, and Wijdicks CA. Correlation of valgus stress radiographs with medial knee ligament injuries: An in vitro biomechanical study. American Journal of Sports Medicine. 2010; 38(2): 330-338. doi:10.1177/0363546509349347.
- Stiell IG. Prospective validation of a decision rule for the use of radiography in acute knee injuries. JAMA: The Journal of the American Medical Association. 1996; 275(8): 611-615. doi:10.1001/jama.1996.03530320035031.
- Halinen J, Koivikko M, Lindahl J, and Hirvensalo E. The efficacy of magnetic resonance imaging in acute multi-ligament injuries. International Orthopedics. 2009; 33: 1733-1738.
- Jacobson JA. Fundamentals of Musculoskeletal Ultrasound. Philadelphia: Saunders; 2007.
- Wilson TC, Satterfield WH, and Johnson DL. Medial collateral ligament “tibial” injuries: indication for acute repair. Orthopedics. 2004; 27(4): 389-393.
- Bollier M and Smith P. Anterior cruciate ligament and medial collateral ligament injuries. J Knee Surg. 2014; 27(05): 359-368. doi:10.1055/s-0034-1381961.
- Tegner Y and Lysholm J. Rating systems in the evaluation of knee ligament injuries. Clin. Orthop. Relat. Res. 1985; (198): 43-49.
- Hauser R and Dolan E. Ligament injury and healing: An overview of current clinical concepts. J Prolotherapy. 2011; 3(4): 836-846.
- Amar E, Snir N, Sher O, et al. Platelet-rich plasma did not improve early healing of medial collateral ligament in rats. Arch Orthop Trauma Surg. 2015; 135(11): 1571-1577. doi:10.1007/s00402-015-2306-7.
- Yoshioka T, Kanamori A, Washio T, et al. The effects of plasma rich in growth factors (PRGF-Endoret) on healing of medial collateral ligament of the knee. Knee Surg Sports Traumatol Arthrosc. 2013; 21(8): 1763-1769. doi:10.1007/s00167-012-2002-x.
- Taylor DW, Petrera M, Hendry M, and Theodoropoulos JS. A systematic review of the use of platelet-rich plasma in sports medicine as a new treatment for tendon and ligament injuries. Clinical Journal of Sport Medicine. 2011; 21(4): 344-352. doi:10.1097/JSM.0b013e31821d0f65.
- Eirale C, Mauri E, and Hamilton B. Use of platelet rich plasma in an isolated complete medial collateral ligament lesion in a professional football (soccer) player: A case report. Asian J Sports Med. 2012; 4(2): 158-162. doi:10.5812/asjsm.34517.
- Ada AM, Yavuz F. Treatment of a medial collateral ligament sprain using prolotherapy: a case study. Altern Ther Health Med. 2015; 21(4): 68-71.
Original Version of the Topic:
Robert Irwin, MD, Michelle D. Francavilla, MD. Medial and lateral collateral ligament injuries. Publication Date: 2012/12/28
Danial Herman, MD:
|Affiliation/Company||What Was Received||For What Role|
|HSS||Cash Honorarium||Grand Rounds|
|World Health Organization||Cash Honorarium||Consulting|
|NIH||Grant Support||Research Grant|
|AMSSM, ACSM||Grant Support||Research Grant|
Justin Weppner, DO
Nothing to Disclose
Sara Raiser, MD
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