MCL sprain: symptoms, grades, recovery time and rehabilitation

The MCL is a band of tissue on the inner side of the knee, connecting the thigh bone to the shin bone. Royal Cornwall Hospitals describes it as one of the ligaments in your knee that keeps your knee joint stable. A sprain means the ligament has been overstretched or torn, and the NHS defines a sprain as a torn or twisted ligament, whereas a strain involves a muscle.

The usual mechanism is a force that pushes the knee inwards, for example a tackle to the outside of the knee in football or rugby, a fall while skiing, or twisting with the foot planted. The NHS Greater Glasgow and Clyde musculoskeletal guidance adds that injuries are more common in high demand sports and usually follow non-contact trauma such as landing incorrectly from a jump, pivoting or decelerating suddenly, but can occur after a direct blow or collision, and often more than one structure is involved with damage to the menisci and articular cartilage seen on MRI.

People typically describe pain and tenderness along the inner side of the knee, which is worse when the knee is stressed sideways, with swelling and stiffness. The NHS lists the general features of a sprain as pain, tenderness or weakness, swelling or bruising, difficulty putting weight on the injury or using it normally, and sometimes muscle spasm.

• Pain along the inside of the knee, especially on twisting or going downstairs.

• Swelling and bruising that may be worse at the end of the day.

• A feeling of looseness or the knee giving way sideways in more severe injuries.

• Difficulty straightening or fully bending the knee.

• Pain on walking, particularly pivoting or changing direction.

Royal Cornwall describes soft tissue knee injuries as graded by severity, and the NHS Greater Glasgow and Clyde guidance links the grades to the amount of sideways opening of the knee joint on testing.

Royal Cornwall advises that in the first 72 hours you rest your leg, elevate it above hip level, apply a cold pack regularly and use crutches for walking or a support bandage. It uses the term PRICER: protect, rest, ice, compression, elevate and rehabilitation. It cautions that ice should not be placed in direct contact with the skin and should not be left on for more than 20 minutes at a time.

The NHS sprains and strains advice is similar: for the first 2 to 3 days follow PRICE, use paracetamol and ibuprofen gel if needed, avoid heat, alcohol and massage in the first couple of days, and start gently moving the joint when you can move it without pain stopping you so that it does not become stiff. The NHS adds that most sprains feel better after 2 weeks, that you should avoid strenuous exercise such as running for up to 8 weeks, and that severe sprains can take months to get back to normal.

A clinician will examine the knee, testing stability by applying sideways stress. Royal Cornwall explains that more severe injuries may need further imaging such as an MRI scan, and that an orthopaedic consultant or a team member supervised by one makes the diagnosis in its fracture clinic. An X-ray can exclude a fracture, particularly after a significant twist or direct blow.

The Glasgow guidance advises that an acute grade 3 or suspected grade 3 tear warrants further evaluation, with clinical assessment and sometimes MRI, to look for other coexisting injuries such as a cruciate ligament or meniscal tear.

Royal Cornwall says physiotherapy is an integral part of managing knee injuries whether or not an operation is needed, and that for some injuries a brace such as a hinged T-scope brace is fitted by the emergency department or minor injuries unit, set to a limited range of movement, worn day and night and removed only to wash or use a cold pack. It says the brace is worn for 6 to 12 weeks depending on severity, with exercises done in the brace three times daily.

The exercises described include static quadriceps contractions, inner range quadriceps work with a towel under the knee, knee flexion and extension within the brace range, straight leg raises, and mini squats once out of the brace. The Glasgow guidance notes that grade I and II injuries are best managed with early functional rehabilitation without the need for bracing, that bracing is recommended for the first 4 to 6 weeks for grade III until the knee is stable, and that evidence is lacking for therapeutic ultrasound.

Estimates differ by grade, by source and by the demands of your sport. Royal Cornwall says the injury will take approximately 3 to 9 months to heal and that the scar matures over 6 weeks to up to a year. The Glasgow guidance states that return to sport can be expected in 6 to 8 weeks, and quotes 2 to 4 weeks for grade I to II lesions in one section. The two are consistent in that mild sprains settle within weeks while full ligament healing and confidence can take months.

Return to sport should be guided by being able to straighten and bend the knee fully without pain, walking, jogging and then change-of-direction work without swelling or giving way, and strength matching the other leg. Pivoting and cutting movements take longest to rehabilitate.

Royal Cornwall says your individual circumstances will guide whether an operation to reconstruct the MCL is recommended and notes that the MCL heals better when the torn ends are in contact. Royal Cornwall describes grade 3 injuries as leaving the knee joint unstable so that you may need an operation, and surgery is also discussed when other major ligament injuries are present or the knee stays unstable despite rehabilitation.

A knee surgeon would discuss risks and benefits so that you can make an informed decision, and prehabilitation exercises are advised to prepare for and recover from surgery.

The NHS says to call 999 or go to A&E if you heard a crack when you had your injury, the injured part has changed shape or is pointing at an odd angle, it is numb, tingling or has pins and needles, or the skin has changed colour or is cold, because you may have broken a bone. It advises getting help from NHS 111 if the injury is very painful or getting worse, there is a large amount of swelling or bruising, you cannot put weight on it or walk more than a few steps, it feels very stiff, or you have a very high temperature or feel hot, cold or shivery.

See a GP or use a self-referral physiotherapy service if the knee is not improving, keeps giving way, or locks or catches, which can suggest an associated meniscal injury.

On the NHS, initial assessment is in an emergency department, minor injuries unit, urgent treatment centre or GP surgery, with fracture clinic, physiotherapy and orthopaedic follow-up where needed. In many areas you can refer yourself to NHS community musculoskeletal services without a GP referral, although the NHS notes that waiting times can be long and that physiotherapy can also be obtained privately.

Private physiotherapy and sports medicine clinics offer quicker access, which is useful for athletes. Check that physiotherapists are registered and ask for a structured, progressive plan that includes strength testing before return to sport.