Written by Dr Sean Leo, a consultant orthopaedic surgeon whose clinical focus is the knee, sports injuries and the lower limb.

Last updated: 9 October 2026.

An MCL tear (medial collateral ligament tear) is an injury to the ligament on the inner side of the knee. Most isolated MCL injuries (where only the MCL is hurt) can be managed without surgery with good results. Outcomes for complete (grade III) tears are less certain.

What is an MCL tear, and how is it treated?

An MCL tear (medial collateral ligament tear) is an injury to the ligament on the inner side of the knee. Most isolated MCL injuries (where only the MCL is hurt) can be managed without surgery with good results. Outcomes for complete (grade III) tears are less certain.
Recovery is guided by how the knee is performing rather than by a fixed date.
Surgery is for a knee that remains unstable despite proper non-operative care, a grade III tear with persistent instability, or an MCL injury combined with another ligament injury.

Primary action: Arrange a knee assessment Destination: Verified OrthoSports appointment/contact route

Secondary action: Read how MCL injuries are assessed and treated Destination: MCL reconstruction page

A netball player bends her knees while preparing to pass on an outdoor neighbourhood court.

Do most MCL tears need surgery?

No. Most isolated MCL injuries can be managed without surgery with good results. Outcomes for complete (grade III) tears are less certain. The MCL is one of the most common knee ligaments to be injured, and surgery is the exception rather than the default.

A 2021 systematic review (a structured summary of earlier studies) of eight randomised trials (trials in which people are assigned to a treatment by chance) found similar knee-function scores after non-operative and operative treatment of grade I to III injuries (Roberts et al., 2021). Quadriceps (thigh muscle) strength was better early on without surgery, at eight weeks, and similar later, and minor complications were less common, although the evidence was limited and the authors noted that the best management of severe injuries remains uncertain.

Non-operative care means protected early movement, progressive strengthening, and weight-bearing as tolerated. Prolonged immobilisation tends to be avoided, and controlled early movement is preferred. Some protocols use a hinged brace, but how braces are used varies between studies and is inconsistently reported, so there is no single standard brace prescription to point to.

A man sits on a park bench and gently straightens one knee in front of him.

How long does an MCL tear take to heal?

How long recovery takes varies from person to person. It is guided by how the knee is actually performing, meaning its stability, strength and movement quality, rather than by a date on a calendar.

You may come across week-by-week figures elsewhere. These are typical rehabilitation-protocol estimates, not guarantees, and they vary from person to person. Treat them as a general guide, not a promise.

What causes an MCL tear?

The MCL is a band of tissue on the inner side of the knee. It is the main restraint that stops the knee from opening inward when sideways force pushes on it.

The typical story is a blow to the outer side of the knee while the foot is planted, which forces the knee inward. This is common in sports such as football, ice hockey and skiing. A sudden twist or change of direction without any contact can cause the same injury.

How are MCL tears graded?

Doctors describe how much of the ligament is torn using the Hughston scale:

Grade I: a few fibres are torn. There is tenderness along the inner knee, but the knee is not unstable.
Grade II: more fibres are torn, tenderness is more widespread, and the knee is still not unstable.
Grade III: the ligament is completely torn, and the knee is unstable: it opens inward when stressed.

The grade tells you how much of the ligament is torn. It does not, by itself, tell you whether you will need an operation. If the knee opens inward even when it is held straight, that can point to a second ligament, usually the ACL, also being injured, and it prompts a check for that. The two injuries can happen together.

A man stands ready to return a ball on a sunny public tennis court.

What are the symptoms of an MCL tear?

The usual features are:

pain and tenderness on the inner side of the knee
swelling
stiffness or reduced movement
in a complete tear, a sense that the knee is unstable

Two swelling patterns are worth knowing. Swelling that appears within about two hours of the injury can suggest bleeding into the joint, which is also seen with an ACL injury. A torn joint capsule may mask swelling, so less swelling than expected does not rule out a significant tear. Neither pattern is a diagnosis on its own, because these symptoms overlap with other knee injuries, which is why a proper assessment matters.

The main diagnostic tool is a physical examination called the valgus stress test. The clinician gently stresses the inner knee — first with the knee bent to about 30°, then again with it straight — comparing how much it opens, and how firm the end-point feels, against your other knee.

When is MCL surgery considered?

Surgery is not the first-line option for an MCL tear. It is considered when:

the knee remains unstable after a proper course of non-operative care,
a grade III tear shows persistent instability, or
the injury is combined with another ligament injury, most often the ACL.

Studies of MCL reconstruction in people who also had an ACL injury most often report lasting looseness despite non-operative care, or a grade III injury, as the reasons for operating (Touhey et al., 2025).

In an older series of complete (grade III) tears that were treated without surgery, a high proportion went on to have persistent looseness of the inner knee and, later, arthritis after injury (post-traumatic arthritis), as summarised by Phisitkul and colleagues (2006). That is why surgeons look carefully at how stable the knee is.

What should I do next?

An inner-knee injury with pain, swelling, stiffness or a knee that feels unstable is a reason to have it assessed. Being assessed does not commit you to surgery, because most MCL injuries can be managed without surgery with good results. For how MCL injuries are assessed and treated, including when surgery is considered, see the MCL reconstruction page. If an ACL injury is also a concern, read about ACL reconstruction surgery. You can also explore the OrthoKinetics Knee Hub.

Related reading

Some signs need help sooner than a routine appointment, and each one says where to go.

Signs that need urgent help

Some symptoms should not wait for a routine appointment. Each item below says where to go.

After an injury

The leg looks twisted or bent, a bone is showing, there is a deep cut, or the foot or leg turns cold, pale, numb, blue or white. Go to an emergency department or call 995.
You cannot lift your leg up with the knee kept straight, and you may feel a gap just above or just below the kneecap. Arrange an urgent same-day assessment.

At any time

The knee is stuck and will not straighten, or it is very painful and you cannot move it or put weight on it. Arrange an urgent same-day assessment.
The knee is suddenly very painful, hot, red and swollen, especially with a fever or feeling generally unwell. Go to an emergency department or call 995.
One calf or thigh is newly painful and swollen. Arrange an urgent same-day assessment. If you also feel short of breath or have chest pain, go to an emergency department or call 995.

After knee surgery

The operated knee becomes more painful, swollen or red, a wound is leaking, or you develop a fever. Go to an emergency department or call 995, or contact your surgical team straight away.

If you are admitted by the doctor at the urgent care centre of one of these private hospitals, the Parkway Pantai hospitals (Mount Elizabeth Orchard, Mount Elizabeth Novena, Gleneagles and Parkway East), Farrer Park Hospital and Thomson Medical Centre, you may ask for Dr Sean Leo to be your attending orthopaedic surgeon. If you are instead discharged and referred for orthopaedic follow-up, you may contact the clinic to arrange an appointment. Both are subject to the hospital’s admission processes and to Dr Leo’s availability.

Arrange an MCL or knee assessment

Read how MCL injuries are assessed and treated

OrthoKinetics does not provide emergency or urgent care through this webpage or its WhatsApp contact.

This article gives general information and cannot diagnose an individual knee injury. Website or messaging contact is not an emergency-response service. For a medical emergency, use your local emergency service.

References

Phisitkul P, James SL, Wolf BR, Amendola A. MCL injuries of the knee: current concepts review. Iowa Orthop J. 2006;26:77-90. PMID 16789454. PMC1888587. Open access.
Svantesson J, Piussi R, Weissglas E, Svantesson E, Horvath A, Börjesson E, Williams A, Prill R, Samuelsson K, Hamrin Senorski E. Shedding light on the non-operative treatment of the forgotten side of the knee: rehabilitation of medial collateral ligament injuries — a systematic review. BMJ Open Sport Exerc Med. 2024;10(2):e001750. doi:10.1136/bmjsem-2023-001750. PMID 38933372. PMC11202733. Open access.
Roberts SB, Brown OS, Beattie N, Brown GS, Maempel JF, White T. Systematic review of randomised controlled trials for interventions to treat injuries to the medial ligaments of the knee. Surgeon. 2021;19(2):111-118. doi:10.1016/j.surge.2020.03.003. PMID 32349920.
Touhey DC, Garcia FN, Tartibi S, Brophy RH, Matava MJ, Smith MV, Knapik DM. Concomitant Anterior Cruciate Ligament and Medial Collateral Ligament Reconstruction: A Systematic Review. Orthop J Sports Med. 2025;13(9):23259671251369019. doi:10.1177/23259671251369019. PMID 40980559. PMC12444044. Open access.
Ade-Conde AM, Cruickshank M, Bouchard MD, Vivekanantha P, Alomari M, Sa D, Kay J. Combined medial collateral ligament and posterior oblique ligament reconstruction demonstrates favourable patient-reported outcomes and medial knee stability in Grade III injuries: A systematic review. Knee Surg Sports Traumatol Arthrosc. 2026;34(4):1292-1309. doi:10.1002/ksa.70344. PMID:41711578. PMCID:PMC13037351.

MCL tear: symptoms, causes and treatment