KNEE INJURIES: MCL INJURIES
Description
●The primary function of the MCL is to resist valgus and external rotation forces of the tibia in relation to the femur. Adults are more susceptible than children or adolescents to MCL injury due to a decline in ligament elasticity. The MCL can also be injured in conjunction with the ACL, PCL, meniscus, bone and/or lateral complex. In knee injuries from cutting maneuvers, valgus forces placed on the knee usually tear the medial capsular ligament first, then the MCL, and finally the ACL. Because the meniscus is firmly attached to the deep MCL, meniscal tears are common alongside MCL tears.
●The MCL has a superficial and deep portion. The superficial MCL resides in the middle layer of the medial compartment of the knee and spans from the medial femoral condyle to its broad insertion at the metaphysis of the tibia, 4-5 cm below the joint line.
●The superficial layer is comprised of sartorius and the investing fascia which forms part of the patellar retinaculum.
●The middle layer includes semimembranosus, the superficial MCL, the medial patellofemoral ligament and the posterior oblique ligament.
●The deep layer includes the deep MCL, the posterior medial capsule, and the meniscotibial ligament.
●The superficial MCL is the principal restraint to valgus forces at the knee joint in all degrees of flexion. The deep MCL resides in the third layer of the medial compartment and is often separated from the superficial MCL by a bursa, which facilitates the two MCL components during flexion. The deep MCL attaches to the medial meniscus but does not aid in resisting valgus stress on the knee but helps resists anterior translation of the tibia. It can be thought of as a thickening of the medial joint capsule, and is divided into meniscofemoral (ligaments of Humphrey and Wrisberg) and meniscotibial (coronary ligament) components.
●The most common location for MCL injuries is the femoral insertion.
History
● Mechanism is typically a large valgus and/or external rotation force that is suddenly placed on the knee joint o Contact mechanisms commonly associated with a blow to lateral knee, involve large valgus stresses and often result in complete MCL tears o Noncontact valgus and external rotational stresses, observed in cutting, pivoting and deceleration motions of the leg, frequently cause partial tears of the MCL o Overuse mechanisms may be observed in sports such as swimming and gymnastics, which place repetitive valgus loads across the knee
● May describe a sensation of the knee “giving out” at the moment of injury
● Most common in sports such as football, skiing and rugby
● Higher grade injuries are usually associated with less pain, perhaps because there is little or no tension on the injured ligament.
● Experience a sense of valgus instability
● May have altered biomechanics leading to post-traumatic arthrosis
● Hearing a pop or a tear may indicate a more serious injury ● Pain and stiffness on the medial side of the knee
● Patients with less severe injuries can typically still move and do not have mechanical symptoms such as locking
● Low-grade injuries are not associated with knee swelling
● Chronic pain and tenderness over the medial tibiofemoral joint line in a patient with a history of falls or knee trauma, may consider Pelligrini-Stieda Syndrome
Physical Exam
● Site of injury along the superficial MCL usually correlates closely with the location of edema and tenderness
● Integrity of MCL is evaluated by assessing medial instability with the abduction stress test (valgus test at 30°) o Degree of laxity in mm should be noted o Quality of endpoint should be noted ▪ Firm end point: intact MCL ▪ Soft end point: torn ligament
● The examination is then repeated in full extension to recruit contributions of posteromedial structures o A positive abduction stress test in full leg extension is highly suspicious for an ACL or PCL injury
● Assess for concomitant injuries
● If assessing on-field, assessment should be done within 20-30 minutes to avoid complications relating to pain, swelling, and muscle spasm Classification
● O’Donoghue classification o Isolated grade 1 MCL injury (mild): few torn fibers but no loss of ligamentous integrity o Isolated grade 2 MCL injury (moderate): partially torn, however fibers are still opposed. There might be mild pathologic laxity, which may or may not be symptomatic. o Isolated grade 3 MCL injury (severe): integrity of the MCL is completely disrupted. There is significant pathologic laxity of the knee with valgus stress
● AMA nomenclature of athletic injuries o MCL injuries are classified based on the amount of medial joint opening when a valgus load is applied at 20-30° of knee flexion o Grade 1: 0-5 mm o Grade 2: 5-10 mm o Grade 3: >10 mm Further Investigations
● Diagnosis can be made reliably with history and physical exam
● Plain radiographs are ordered according to the Ottawa knee rules
● MRI provides excellent visualization of soft tissue anatomy and is indicated if injury to menisci, ACL or PCL is suspected o May also identify bone bruises or osteochondral fractures o Can also identify site of MCL tear, but is not accurate for determining grade of injury Prognosis
● Prognosis for return to preinjury level is excelling, time for returning to sport depends on the grade of the injury o Grade 1: 2-3 weeks o Grade 2: 3-4 weeks o Grade 3: 6-12 weeks
● Isolated partial MCL ruptures have been found to have only a 10% incidence of reinjury within 10 years
Treatment Options
● Healing of grade 1 and 2 MCL injuries usually follows a relatively predictable sequence o Hemorrhage o Inflammation o Proliferation o Remodeling
● Most MCL injuries are treated conservatively (RICE, protective ambulation and physical therapy)
● Acute treatment
o All suspected knee sprains should be treated with RICE protocol
o NSAIDs can be used to reduce swelling and provide pain relief
o If unstable or exceptionally painful, a hinged brace or immobilizing knee brace and/or crutches should be used
o Grade 1: do not usually require protective ambulation
o Grade 2 and 3: usually require protective ambulation
o Grade 3 injuries should be immobilized with a hinged brace set at 30° flexion to minimize the distance between the 2 ends of the torn ligament
▪ Should be worn for 4-6 weeks
● Physical therapy
o After swelling subsides and the patient can ambulate more easily, should seek out physical therapy o Aim to improve quad and hamstring strength
o Most MCL injuries, even grade 2 injuries, will heal non-operatively o Restore ROM and improve muscle strength, resulting in decreased pain and increased knee function o Start with low-impact exercises, gradually progressing to more sport/activity-specific exercises
o When sport-specific exercises, particularly those involving cutting and pivoting can be performed without discomfort, patients are allowed to return to competitive play
o It's always a great idea to see a chiropractor in Saanich to help guide you on your return to sport post knee injuries.
● Surgery
o Rarely require surgical reconstruction
o Exceptions are chronic MCL injuries (>3 months duration with high-grade laxity) that have failed non-operative treatment and certain multiple-ligament knee injuries
o Tibial-sided grade 3 MCL injuries are more prone to persistent laxity even after conservative management
▪ They often have valgus instability even with ADLs o Acute grade 3 MCL injuries may warrant operative intervention if there is also a large bony avulsion, tibial plateau fracture, intra-articular entrapment of the end of a ligament, or anteromedial instability
▪ If surgery occurs, it is usually within 7-10 days after the injury
● Operative Treatment Rehab
o The same staged, criteria-based progression model can be used, with the addition of healing time considerations and surgeon preferences
o ROM is typically progressed slower
o Full ROM as tolerated begins 4 weeks after surgery o Ideal to have full ROM at 6-8 weeks, but may take 6-10 weeks to achieve full, pain-free ROM
● Return to Sport
o There is lack of evidence as to whether or not bracing the injured lower extremity prevents further injury in the scenario of isolated MCL injuries
References
1. BMJ Best Practice 2. Andrews et al. Review: Medial Collateral ligament injuries. J Orthop. 2017 Aug 15;14(4):550-554. 3. Kim et al. Return to play after medial collateral ligament injury. Clin Sports Med. 2016 Oct;35(4):679-96.
---------------------------------------------------------
Dr. Mike Hadbavny
Victoria Sports Chiropractor FRCCSS(C)
If you are interested in learning more about how seeing a Saanich chiropractor can be effective for your particular condition or health goals, contact Dr. Mike Hadbavny at 250-881-7881 today to make an appointment and discover the many benefits of seeing a chiropractor in Victoria BC. Contact us today
コメント