Knee MRI following a sports injury
Magnetic resonance imaging (MRI) of the knee following a sports injury is the diagnostic standard. It detects damage to the menisci, ligaments, cartilage and bone with greater accuracy than any other examination. In this article, I will explain what a radiologist sees on an MRI scan of the knee following typical injuries (sprains, falls, football injuries), when surgery is necessary, and when physiotherapy is sufficient.
In this article
The most common knee injuries detected on MRI
1. Medial meniscus injuries (the most common, ~70% of all meniscus injuries). 2. Anterior cruciate ligament (ACL) injuries – the classic ‘pivot shift’ injury in football and skiing. 3. Medial collateral ligament (MCL) injuries. 4. Articular cartilage damage – early degenerative changes. 5. Occult fractures not visible on X-ray.
Classification of meniscal injuries on MRI
Scale 0–3: 0 = normal meniscus; 1 = signal within the meniscus, not extending to the surface (degeneration, usually asymptomatic); 2 = linear signal, not reaching the surface (clinically insignificant degeneration); 3 = tear reaching the articular surface (clinically significant, possible indication for arthroscopy). Only grade 3 is a ‘true tear’ often requiring surgical treatment.
ACL – complete or partial tear?
MRI distinguishes between a complete ACL injury (rupture, joint instability – an indication for reconstruction in athletes) and a partial injury (continuity preserved, physiotherapy possible). In young athletes, a complete ACL injury almost always requires reconstructive surgery – otherwise there is a risk of early degenerative joint disease and recurrent injuries.
Bone bruise – a sign that something serious has happened
Bone bruise = subchondral oedema visible on MRI as a bright T2 signal. This indicates that bone-on-bone impact has occurred. The classic pattern of “bone bruise in the lateral aspect of the femur + posterior aspect of the tibia” is pathognomonic for a recent ACL injury – even if the ACL itself looks fine at that moment. Bone bruises resolve within 6–12 months.
What to do after the MRI results – clinical decision
Every MRI result must be interpreted in the context of: the patient’s age, level of sporting activity, mechanism of injury, and clinical examination (Lachman test, McMurray test, etc.). A 30-year-old footballer with a complete ACL tear → arthroscopic reconstruction; A 60-year-old recreational runner with the same injury → often physiotherapy, braces, modification of activity. APERTA provides the radiological report – the treatment plan is determined by an orthopaedic surgeon or physiotherapist.
Frequently asked questions
How long after the injury should an MRI be performed?
Ideally after 2–3 days (once the acute swelling has subsided).
Will an MRI show how long it will take to return to sport?
Indirectly – consult a sports physiotherapist.
I have knee pain without an injury – do I need an MRI?
Not always. Start with an X-ray and a consultation with an orthopaedic surgeon.
Is an MRI better than arthroscopy?
An MRI is diagnostic. Arthroscopy is a treatment.
Can I have an MRI whilst in a cast?
Yes, plaster casts do not interfere.
How much does a knee MRI cost?
Get in touch – packages for athletes are available.
This content is for information purposes only and does not replace a medical consultation.
