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Which ligaments are involved?
The medial collateral ligament, or inner side ligament, connects the thigh bone to the shin bone on the inside of the knee. The lateral collateral ligament, or outer side ligament, connects to the fibula, the smaller bone alongside the shin bone. They help control sideways movement.
A sprain can range from stretching to a complete tear or an attachment being pulled away. Professionals sometimes use grades to describe severity. However, an isolated injury and an injury involving the ACL, a meniscus or other structures are not managed in the same way.
Chapter sources [1]
Understand the picture
The side ligaments
Inner ligament
It connects thigh bone to shin bone.
Outer ligament
It connects thigh bone to fibula.
Overall stability
Other structures also need examination.
Chapter sources [1]
How can a sprain happen?
A blow to one side of the knee, a change of direction or a twist can load a ligament beyond its capacity. Contact or pivoting sports are possible settings, but a fall or everyday accident can also be responsible.
The direction of the blow helps the doctor understand the mechanism without proving which structure is injured. An outer-side injury can accompany more complex damage. Do not conclude that it is a simple sprain because pain seems limited to one spot or you can still walk.
Chapter sources [1]
Which symptoms should you report?
Pain is often on the injured side, with tenderness, swelling and stiffness. Bruising may appear. You may feel giving way or be afraid to bear weight. The amount of pain cannot tell you the grade of the sprain on its own.
Explain when swelling appeared, whether there was a noise during the accident and which movements became impossible. Also mention numbness or difficulty moving the foot. Do not ask a relative to push the knee sideways to check its stability.
Chapter sources [1]
When should you seek urgent help?
Deformity, inability to bear weight, very severe pain or a cold, pale or numb foot needs urgent assessment. An injury involving several ligaments may require checking blood vessels or nerves. Do not walk to test a deformed leg.
A red, hot knee with fever also needs prompt advice the same day. If a calf suddenly becomes swollen and painful during recovery, seek prompt assessment. With associated breathlessness or chest pain, call 112 in Luxembourg. These signs are not part of normal training.
What does the medical assessment look for?
Examination assesses ligaments, movement, menisci and, depending on the injury, circulation and sensation. A review may be necessary when early swelling limits examination. Comparing with the other knee helps but does not replace the whole assessment.
An X-ray may look for a fracture or a piece of bone pulled away at an attachment. MRI can clarify ligaments and associated injuries when this affects treatment. Ask which structures are involved, which loads to avoid and when to see the doctor again. “Sprain” alone does not answer these practical questions.
Brace, crutches or surgery: why do plans differ?
Many isolated inner collateral ligament sprains are treated without surgery. Depending on stability and severity, a hinged brace or crutches may protect the knee while allowing permitted movement. Some outer-side injuries, pulled-off attachments or associated injuries require specialist discussion.
Do not choose a brace simply because it looks more rigid. Its settings, duration and weight-bearing limits need clarification. Surgery is not decided from a grade number alone. Goals, instability and other injured structures form part of the decision.
What is physiotherapy’s role?
Rehabilitation supports recovery of movement, walking and strength within prescribed protection limits. Work then develops balance, control and useful movements. Persistent stiffness and lost strength can limit return even when pain decreases.
Your physiotherapist checks the knee’s response and adapts exercises. Movements that push the knee sideways or involve pivots are not tests to add yourself. The Exercises page is general support; after a recent sprain, have selected movements and their dose approved.
Chapter sources [1]
In everyday life
Prepare a return to work
List the demands
Journeys, stairs, pivots and lifting.
Adapt temporarily
Choose tasks compatible with protection.
Reassess abilities
Increase after checking stability and the knee’s response.
Chapter sources [1]
What can you do at home in the first days?
Organise journeys to respect permitted weight-bearing. Keep useful items accessible, use prescribed aids and ask how to manage stairs. Wrapped cold may provide comfort if sensation and circulation allow; protect the skin and stop if it reacts badly.
For medicines, seek advice based on your history and other treatments. Less pain while taking medicine does not mean stability has returned. For sleep, choose comfortable support and follow instructions for wearing the brace without changing its settings yourself.
How can you return to work and sport?
Desk work differs from a job involving pivots, stairs or carrying loads. Temporary adaptations can avoid moving directly from rest to a difficult full day. Driving requires control of the vehicle and the ability to react in an emergency; a brace or some medicines may prevent this.
For sport, pain-free walking is only an early marker. Your team checks mobility, strength, stability and activity-specific movements. Adapted training may come before competition. Extra protection may be discussed, without guaranteeing freedom from another injury.
What progress can you expect, and when should you review?
A minor isolated sprain may improve over a few weeks; a major tear or associated injury often needs longer. These estimates do not authorise return to activity. Stability and function should progress with the planned stages.
A knee that still gives way, remains markedly swollen or does not regain movement needs reassessment. Also seek advice if the brace injures the skin or instructions are unclear. A new twist during recovery warrants another assessment even if it resembles the original accident.
Your questions
Is a sprain always less serious than a tear?
No. Sprain includes different degrees of ligament injury, including tears. The ligament involved, stability and associated injuries must be specified to understand the situation.
Chapter sources [1]
Can I remove the brace as soon as pain improves?
Not without checking the instructions. It may protect a ligament during a period when pain has already decreased. Ask when to remove it for personal care, sleep and exercise.
Chapter sources [5]
Should I remain completely still?
This depends on the injury. Protection may be combined with permitted movement to limit stiffness. An individual programme specifies what is allowed, rather than giving everyone complete rest or unrestricted exercise.
Chapter sources [1]
Why examine the other ligaments?
One twist can injure several structures. Associated damage may change protection, the value of MRI and treatment options, even when pain seems mainly on one side.
Chapter sources [1]
Sources and references
- [1] AAOS OrthoInfo — Collateral Ligament Injuries
- [2] Assurance Maladie — Douleurs du genou : que faire et quand consulter ?
- [3] NHS — Baker’s cyst
- [4] HAS — Pertinence de l’imagerie en cas de gonalgie chez l’adulte
- [5] Assurance Maladie — Traitement de l’entorse du genou
- [6] NHS BNSSG — Patellar tendinopathy : symptoms, load and exercises
- [7] CGDIS — 112 Luxembourg
Text updated on
Medical review: awaiting Hasib Selimovic.