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How should you use these signs?
Start with what has changed: an accident, loss of the ability to bear weight, rapid swelling, fever or a new leg symptom. The speed of onset and your general health matter. An existing diagnosis, such as osteoarthritis or a Baker’s cyst, does not explain every new change.
The groups below describe actions, not diagnoses. A situation can become more urgent if it worsens. You do not need to have every sign on a list before seeking help. If you cannot travel safely or your condition is deteriorating, seek urgent assistance.
Chapter sources [1]
Understand the picture
Choose an action according to the signs
Emergency
Serious accident, major deformity, poor circulation or chest symptoms: immediate help.
Prompt assessment
A hot, swollen knee, a truly locked knee or sudden calf swelling: do not wait for physiotherapy.
Consultation and follow-up
Persistent or recurring symptoms: assessment and review, even without an obvious emergency.
When should you call 112 in Luxembourg?
Call 112 for an emergency, including a serious accident with a major deformity, a severe wound, heavy bleeding, or a foot that becomes cold, pale or numb. Loss of consciousness or feeling seriously unwell increases the urgency. Do not try to put a joint or bone back into place.
Chest pain or breathlessness with a recently painful, swollen leg can indicate a serious complication and also warrants a call to 112. Do not drive yourself. Give your location, explain what happened and describe the symptoms. Follow the operator’s instructions.
After a twist, fall or blow
Seek prompt assessment if you cannot bear weight, have severe pain, marked swelling or a lasting loss of movement after an injury. The examination may look for a fracture, ligament or meniscus damage, or another injury. Being able to take a few steps does not rule out every significant injury.
Stop the activity that caused the accident. Support the leg without forcing it and avoid trying jumps, pivots or deep knee bends. A kneecap that appeared to move out of place and then moved back still needs assessment. If the knee remains deformed or you cannot move safely, seek urgent help.
A hot, red and swollen knee: assessment the same day
A very swollen, hot or red knee, especially with fever, chills or feeling unwell, needs prompt medical assessment that day. An infection in the joint or surrounding tissues may need to be investigated. No fever does not rule out infection, particularly if your general health is affected or your immune system is weakened.
Do not start strenuous exercises or massage a suspicious area to reduce the swelling. Mention any wound, recent operation, diabetes or medicine that suppresses your immune system. If your condition deteriorates markedly or you feel very unwell, the situation becomes more urgent.
A locked knee or sudden loss of movement
A knee that remains unable to straighten or bend normally needs prompt assessment, especially after a twist. Pain limiting a movement and a physical obstruction can feel similar. Do not force the knee to work out the difference yourself.
Suddenly being unable to straighten the knee using your muscles after an effort or accident also needs urgent medical advice. A simple click without loss of movement or other signs is different, but repeated painful catching deserves a consultation. Explain which movement is impossible and exactly when this started.
A painful or swollen calf: do not jump to conclusions
Sudden swelling of one leg, calf pain, warmth or a change in skin colour needs prompt assessment that day. A blood clot in a vein and a ruptured Baker’s cyst can cause similar signs. A test you perform at home cannot reliably tell them apart.
This matters particularly after an operation or a period of immobilisation, but these are not the only circumstances. Do not massage the calf to try to release the swelling. If breathlessness, chest pain or feeling seriously unwell develops, call 112 immediately instead of waiting for an appointment.
Chapter sources [3]
After surgery or while taking certain medicines
Contact your surgical team promptly if a wound is leaking, redness is spreading, you have a fever or pain is worsening in an unusual way. New difficulty walking or loss of function after a knee replacement must also be reported. Your discharge instructions should explain who to contact.
Marked swelling while taking anticoagulants needs medical advice that day. Do not change the medicine yourself to try to reduce the swelling. Bring a list of medicines and say when you last took them. Preventive treatment does not allow every complication to be ruled out remotely.
In everyday life
Share the useful information
Explain what is new
An accident, swelling, fever or an impossible movement.
Give the context
Surgery, a joint replacement, illnesses and medicines.
Follow the advice
Arrange care and transport according to the instructions you receive.
Chapter sources [9]
Which symptoms should not be left for months?
Arrange a consultation if giving way, swelling or locking keeps returning, stiffness is marked or pain is worsening despite adjustments. Persistent pain at rest or at night, unexplained weight loss or a change in your general health should be discussed with a doctor.
In a child or teenager, a lasting limp or unusual pain deserves assessment and should not simply be called growing pains. These signs do not identify one particular illness. They mean the assessment needs to be reconsidered and the urgency of any tests decided from the whole situation.
What should you prepare for the call or consultation?
Explain the onset, any accident, how quickly swelling developed and what you can no longer do. Mention fever, a wound, breathlessness or chest pain. Tell the professional about recent surgery, a joint replacement, known illnesses and medicines, especially anticoagulants.
Have any available medical reports ready, but do not delay help while looking for them. A photograph may help describe a change but cannot replace an examination. Say if you need help communicating or travelling. Practical information helps the service arrange appropriate care.
Chapter sources [9]
What if none of these signs is present?
You can discuss a routine assessment and cautious adjustments when your condition is stable and activity remains possible. However, the absence of a warning sign on this page does not prove that everything is harmless. Pain that persists, changes or limits your life deserves a consultation.
KinéCheck can help you prepare questions, but it does not confirm a diagnosis or replace emergency services. A contact form or appointment request must never delay necessary care. If the situation changes, reconsider what help you need rather than relying on an answer received earlier.
Your questions
Should I wait for a fever before seeking help for a hot, red knee?
No. An infection can be present without fever. Spreading redness, severe pain, marked swelling or worsening general health needs prompt medical advice.
I can walk: does that rule out a serious injury?
No. Being able to bear weight provides information but does not rule out every injury. Rapid swelling, instability or a loss of movement after an accident needs assessment in context.
Chapter sources [1]
Does a known cyst always explain a swollen calf?
No. A ruptured cyst and a blood clot can look similar. Have a sudden change assessed promptly and call 112 if breathing or chest symptoms occur as well.
Chapter sources [3]
Can I send the practice a form in an emergency?
An online request is not an emergency service and does not guarantee an immediate response. Use the appropriate medical services. In Luxembourg, call 112 in an emergency.
Chapter sources [2]
Sources and references
- [1] Assurance Maladie — Douleurs du genou : que faire et quand consulter ?
- [2] CGDIS — 112 Luxembourg
- [3] NHS — Baker’s cyst
- [4] NHS — Dislocated kneecap
- [5] AAOS — Prepatellar bursitis
- [6] AAOS — Acute Isolated Meniscal Pathology (2024)
- [7] NICE NG157 — Joint replacement
- [8] AAOS OrthoInfo — Osgood-Schlatter Disease
- [9] Assurance Maladie — Gonalgie : consultation médicale et traitement
- [10] Royal Children’s Hospital — The limping or non-weight bearing child
- [11] AAOS — Patellar tendon tear
Text updated on
Medical review: awaiting Hasib Selimovic.