Inner knee ligament sprain

Also called: MCL sprain; medial collateral ligament injury; knee that got hit from the outside

Exercise is the main treatment Strength Stretch Massage Balance

A blow to the outside of the knee, or a ski or football twist, stretches the ligament on the inside. Almost all heal without surgery because the blood supply is good - but the quadriceps switch off, the knee stiffens, and the weak hips that let it happen are still weak.

How common: The commonest knee ligament injury - at least 42% of them, about 74,000 a year in the US, and the number one knee injury in high school sport

Open the Knee Injury Prevention (ACL & Landing) routine All problems

What it is

The medial collateral ligament runs along the inside of the knee and resists the knee being pushed inward. It is injured by a valgus force - a tackle from the outside, a ski catching an edge, a football challenge - and it is the most commonly injured knee ligament.

It also has one of the best healing capacities in the knee, because unlike the ACL it sits outside the joint with a good blood supply. Most sprains, including many complete tears, heal without surgery. The problems that persist are usually not the ligament: quadriceps inhibition from swelling, lost range from stiffening, and the hip weakness that allowed the knee to collapse in the first place.

What it feels like

Pain along the inside of the knee, tender to press on a line rather than a point
Pain when the knee is pushed inward or when twisting outward
Swelling on the inside of the knee, often less dramatic than an ACL injury
A feeling of instability on uneven ground or when changing direction
Stiffness developing over the following days

What causes it

Most people have more than one of these at once, and they feed each other. Read the list looking for the two or three that sound like your week rather than for the one true answer — the ones that describe you are the ones worth acting on.

A valgus force to the knee: A blow to the outside of the knee, or a twist with the foot planted and the knee driven inward. Skiing, football, rugby and wrestling account for most of them.
Hip abductor weakness: Weak glutes let the knee fall inward during landing and cutting. The knee arrives at the challenge already in the position that stresses the ligament, which is why it is a prevention target as well as a rehabilitation one.
Quadriceps inhibition from swelling: Joint swelling reflexively switches off the quadriceps. That happens within days and does not reverse by itself, which is why quadriceps weakness so often outlasts the ligament healing.
Stiffening from reduced movement: Pain and swelling reduce movement, the joint stiffens, and lost extension in particular changes how the whole leg loads. Early controlled range work prevents this.
Returning to sport too early: The ligament heals over weeks, but strength and control take longer. Returning before the leg is equal to the other side risks re-injury and other knee injuries.
Associated injuries: A significant valgus force can also injure the ACL and the medial meniscus. Persistent instability, locking or a knee that gave way at the time needs assessment for these.
Poor landing and cutting mechanics: The same patterns that cause ACL injuries - stiff landings, knee valgus, quadriceps dominance - raise the risk here too and respond to the same training.
Playing surface and equipment: High-friction surfaces and, in skiing, bindings that do not release increase the forces reaching the knee.
A previous MCL injury: A previously injured ligament is slightly more lax and the surrounding control is often incompletely restored, both of which raise the risk of it happening again.

Who tends to get it

Skiers, footballers, rugby players and anyone in a contact or pivoting sport
Anyone with weak hip abductors, which is most people who do not train them
People who have had a previous knee injury
Athletes returning to sport before objective strength testing
Anyone whose knee visibly collapses inward on landing or squatting

What makes it worse, and what settles it

Makes it worse

Prolonged immobilisation, which stiffens the joint and weakens the leg
Returning to cutting sports before the strength and control are back
Ignoring quadriceps inhibition, which persists silently
Losing full knee extension, which changes the whole leg's loading
Never addressing the hip weakness that allowed it

Settles it

Early controlled movement and range work, which produces better outcomes than immobilisation
Quadriceps activation work early, to counter the swelling-driven inhibition
Hip abductor and glute strengthening, which is both rehabilitation and prevention
Progressive loading and then landing and cutting practice before return to sport
A hinged brace where advised, which allows movement while protecting against valgus

What actually helps

The short version: A blow to the outside of the knee or a ski, football or soccer valgus twist stretches or tears the ligament on the inside. Almost all heal without surgery because the ligament has a good blood supply, but the quadriceps switch off from the swelling, the knee stiffens, and the hip muscles that should have stopped the knee collapsing inward were weak before the injury

Strength work: Legs: Quads - quad sets and straight-leg raises from day one, then squats and step-ups; Legs: Quads: Vastus Medialis; Legs: Hamstrings; Glutes: Med and Hips: Abductors - the valgus control; Glutes: Max; Hips: Adductors later; Legs: Calves: Soleus

Stretching: Legs: Quads; Legs: Hamstrings; Legs: Calves; Hips: Flexors - restore full straightening first, then bending

Massage: Legs: Quads; Legs: Hamstrings; Hips: Iliotibial (IT) Band - around the knee, never over a fresh ligament

Also worth doing: A hinged brace for a grade 2 or 3 tear as the clinician advises; ice and elevation in the first days; weight-bear as tolerated with crutches only while limping; landing and cutting drills before returning to sport - about 10 days for grade 1, three weeks for grade 2, two months for grade 3

What the evidence says: Isolated MCL injuries have good outcomes with non-operative rehabilitation focused on knee strength, mobility, stability and functional movement; grade 1 and 2 tears return to sport in 10-20 days on average and grade 3 in about two months. Quadriceps inhibition from pain and swelling is the first thing to reverse.

The names above are the Targets qFIT tracks — the Muscle Guide explains what each one does, and Quick Add switches on the Exercises you already have.

The qFIT routine for this

Ready-made routineKnee Injury Prevention (ACL & Landing)

qFIT already has this one built. It runs massage first, then stretching, then strength — the order that works on a body that is already sore — and every activity in it carries the reason it is there.

The button below opens your Checklist with this routine already selected, so instead of your whole list you land on just its Categories, Targets and Exercises, each with its checkbox, ready to tick as you work through them.

Open this routine in my Checklist

Have more than one problem? Tick yours under My Problems on My Profile and your Checklist's Routine list gains Recommended for my problems — every routine for the problems you picked, merged into one. Your picks stay private; that filter is the only thing they feed.

Get it checked if…

A knee that gives way, locks, or swelled up within an hour of the injury - possible ACL or meniscus tear, needs assessment; inability to bear weight; numbness or a cold foot below the knee - urgent

And whatever the body part: chest pain or unusual breathlessness on exertion; a fever alongside the pain; unexplained weight loss; pain that is constant and unrelated to how you move; new numbness, weakness or loss of bladder or bowel control; or one calf that is swollen, warm and painful. Any of those, stop and get assessed.

How it usually goes

Low-grade sprains settle in two to four weeks and higher grades in six to twelve, and the great majority heal without surgery. What determines the outcome is what happens afterwards: quadriceps strength and hip control need restoring to match the other side before returning to sport. A knee that gave way at the time of injury, that locks, or that remains unstable after the ligament has healed needs assessment for an associated ACL or meniscal injury.

Prevalence basis: StatPearls medial collateral ligament injury; sports injury surveillance

Others the same routine covers

These share the Knee Injury Prevention (ACL & Landing) routine, so the work is the same. If one of them also sounds like you, that is a reason to expect more from it, not less.

This is general information, not a diagnosis, and it cannot examine you. If it matches you, use it to ask better questions of a clinician rather than to replace one.

← All 267 problems 🪯 Muscle Guide