Skip to main content

Health condition · Clinically reviewed

Knee injuries, ligament, meniscal, cartilage - a hub guide.

From a twisted knee on the pitch to a stubborn effusion after a fall - a plain-English map of the injuries, tests and treatments that matter.

Jump to treatment
A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against NICE, BOA/BASK and peer-reviewed orthopaedic sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK practice including MRI-first pathways, ACL reconstruction and cartilage repair.

Key facts

Knee injuries at a glance.

The essentials, in plain English - the main types, the clues that separate them and the pathway that follows.

  • What it is

    A hub guide to the full range of knee injuries - ligament, meniscal, cartilage, patellar, fracture, tendon and paediatric.

  • Mechanism matters

    Twist on a planted foot, direct blow, awkward landing or overuse - each mechanism points to specific structures.

  • Swelling timing

    Immediate haemarthrosis suggests ligament rupture or fracture. Delayed effusion suggests meniscal or cartilage injury.

  • Mechanical symptoms

    Locking, catching and giving way are structural signals - meniscal, cartilage or patellar instability until proven otherwise.

  • First-line imaging

    MRI is the workhorse for soft-tissue knee injuries. X-ray first if fracture is possible.

  • Recovery

    Physiotherapy is central. Surgery is reserved for high-grade, unstable or unresolving injuries under specialist care.

Types of injury

Ten families of knee injury.

Knee injuries are best understood by the structure damaged. Each family below links to a dedicated guide with symptoms, tests and treatment.

Iliotibial band pain in runners and cyclists has its own guide - see iliotibial band (ITB) syndrome.

How the diagnosis is made

From injury to a clear plan.

The steps a UK GP, sports physician or knee surgeon will normally follow - so you know what to expect and why.

  1. 01

    Assessing

    History and mechanism

    A structured account - what you were doing, the direction of force, a pop or crack, and how quickly the knee swelled.

  2. 02

    Assessing

    Structured examination

    Effusion, range of motion, joint-line tenderness and gait - the groundwork before any special tests.

  3. 03

    Assessing

    Ligament stress tests

    Lachman and pivot shift for the ACL, posterior drawer for the PCL, valgus and varus stress for the MCL and LCL.

  4. 04

    Confirming

    Meniscal and cartilage tests

    McMurray, Thessaly and Apley grind tests point to meniscal or chondral injury and guide imaging.

  5. 05

    Confirming

    X-ray if fracture possible

    Direct blow, inability to weight-bear or bony tenderness triggers plain films - to exclude tibial plateau, patellar or condylar fracture.

  6. 06

    Planning

    MRI scan

    MRI is the definitive test for ligament, meniscal and cartilage injury. Often requested at the first specialist review.

  7. 07

    Planning

    Specialist MDT review

    A knee surgeon, sports physician and specialist physiotherapist plan surgery, rehabilitation or watchful waiting together.

Typical timeline: first review to MRI and settled plan in one to three weeks. See our private MRI scan guide.

Symptoms

What knee injuries actually look like.

The patterns that separate ligament, meniscal, cartilage and bony injuries - and the features that mean urgent care.

  • Immediate haemarthrosis

    A hot, tense swelling within an hour of injury - suspect ACL rupture, patellar dislocation or intra-articular fracture.

  • Delayed effusion

    Swelling appearing overnight or over 24 hours - more typical of meniscal, chondral or overuse injury.

  • Locking or catching

    The knee jams or clicks painfully - a mechanical block, often a bucket-handle meniscal tear or loose chondral fragment.

  • Giving way

    The knee buckles under load - ligament instability, patellar maltracking or quadriceps inhibition.

  • Joint-line pain

    Sharp, well-localised pain along the medial or lateral joint line - classic for meniscal or chondral injury.

  • Anterior knee pain

    Pain around the patella with stairs, squats or sitting - patellofemoral, patellar tendon or Osgood-Schlatter in adolescents.

  • Posterolateral pain

    Lateral knee pain with running or cycling - iliotibial band syndrome, LCL or posterolateral corner injury.

  • Red flag - deformity or dislocation

    A visibly deformed knee, inability to weight-bear or a cold foot - a surgical emergency needing immediate hospital care.

Treatment

How knee injuries are treated in the UK.

PRICE and progressive load first, then physiotherapy for most - with surgery reserved for high-grade, unstable or unresolving injuries.

  • PRICE and early load

    Protection, relative rest, ice, compression and elevation in the first days - then progressive weight-bearing as pain allows.

  • Physiotherapy-led rehabilitation

    The foundation for almost every knee injury - restoring range, quadriceps and hamstring strength, balance and sport-specific control.

  • Bracing and offloading

    Hinged braces for ligament sprains, patellar stabilising braces for maltracking, offloader braces for chondral injury.

  • Injection therapy

    Corticosteroid, hyaluronic acid or PRP - selected cases of bursitis, tendinopathy or early chondral disease under specialist review.

  • Meniscal surgery

    Arthroscopic repair for peripheral tears, partial meniscectomy for irreparable ones, root repair for meniscal root tears.

  • Ligament reconstruction

    ACL reconstruction for unstable knees, PCL and multi-ligament reconstruction under specialist knee surgeons.

  • Cartilage repair

    Microfracture, ACI/MACI or osteochondral grafting for full-thickness chondral defects in appropriate patients.

  • Fracture fixation

    Open reduction and internal fixation for displaced tibial plateau, patellar or condylar fractures - specialist commissioned care.

See our dedicated guides on ACI/MACI cartilage repair and microfracture.

What this guide is based on

The sources behind every claim on this page.

UK national guidance and specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP, sports physician or knee surgeon knows your history and can tell you which parts apply to you. If in doubt, get seen.

  • NICE. Knee pain - assessment (Clinical Knowledge Summary).

  • British Orthopaedic Association (BOA) and BASK. Standards for knee injury care.

  • ESSKA. European guidelines on ACL, meniscal and cartilage injury.

  • BJSM. British Journal of Sports Medicine consensus on ACL and meniscal management.

Red flags

When a knee injury needs urgent attention.

Most knee injuries are manageable in primary and community care. These are the patterns that are not - and where hospital review is essential.

  • Knee dislocation

    A dislocated knee is a limb-threatening emergency - carries a high risk of vascular injury and needs immediate hospital review. See our knee-dislocation guide.

  • Cold, pale or pulseless foot

    Any circulatory change after knee trauma is a vascular emergency until proven otherwise - call 999.

  • Locked knee

    A knee that cannot be straightened suggests a bucket-handle meniscal tear or loose body - needs urgent orthopaedic review to prevent chondral damage.

  • Suspected fracture

    Inability to weight-bear, bony tenderness or visible deformity after trauma warrants immediate X-ray in an urgent care setting.

  • Extensor mechanism rupture

    Inability to straight-leg raise after a fall suggests patellar tendon, quadriceps tendon or patellar fracture - needs surgical repair within weeks.

  • Septic joint

    A hot, exquisitely painful knee with fever - especially after an injection or wound - is septic arthritis until proven otherwise.

  • Deep vein thrombosis

    Calf swelling, tenderness or breathlessness after a knee injury or surgery needs same-day medical assessment.

  • Compartment syndrome

    Disproportionate pain, tense swelling and pain on passive stretch after high-energy trauma - a surgical emergency.

  • Paediatric physeal injury

    Any significant knee injury in a growing child needs prompt orthopaedic review - growth plates can be involved and mimic sprains.

Living with it

A treatable injury, with a clear ladder.

Four principles that make the biggest difference through recovery - loading early, building strength, using criteria to return to sport and escalating when needed.

A quiet reminder

Consistency beats intensity, every time.

Small, steady rehabilitation - kept up for months - does more than a heroic week that does not last.

  1. 01 Load

    Move early, load progressively

    Prolonged rest weakens the quadriceps quickly. Guided progressive loading, not immobility, drives recovery.

  2. 02 Strength

    Quads are the engine

    Quadriceps strength predicts outcome after almost every knee injury - from meniscal tears to ACL reconstruction.

  3. 03 Return

    Return to sport is a criteria decision

    Weeks on a calendar do not decide return to pivoting sport - strength, hop tests and confidence do.

  4. 04 Escalate

    Do not accept instability

    A knee that keeps giving way, locking or swelling needs a specialist opinion - untreated instability damages cartilage.

Frequently asked

Everything we get asked about knee injuries.

Quick answers on the main types, MRI, surgery and return to sport.

  • What are the main types of knee injuries?

    Knee injuries fall into ligament (ACL, PCL, MCL, LCL, posterolateral corner), meniscal (medial, lateral, root and bucket-handle tears), cartilage (chondral and osteochondral), patellar (dislocation, tendon rupture, fracture), bony fractures (tibial plateau, femoral condyle, tibial spine), tendon (patellar, quadriceps, iliotibial band) and paediatric (Osgood-Schlatter, Sinding-Larsen-Johansson). Each has its own presentation and pathway.

  • What does the timing of swelling tell you?

    Immediate swelling within an hour usually means bleeding inside the joint - suspect an ACL rupture, patellar dislocation or intra-articular fracture. Swelling that develops overnight or over a day suggests a meniscal tear, cartilage injury or overuse condition. It is one of the most useful clues in the history.

  • When is an MRI needed?

    MRI is the definitive test for soft-tissue knee injuries and is often requested at first specialist review. It shows ligament tears, meniscal injury and cartilage damage in detail. See our private MRI scan and MRI arthrogram guides. X-ray comes first if a fracture is suspected.

  • Do all knee injuries need surgery?

    No - most do not. Grade I and II ligament sprains, small stable meniscal tears, patellar tendinopathy and iliotibial band syndrome respond to structured physiotherapy. Surgery is reserved for complete ligament ruptures with instability, mechanically symptomatic meniscal tears, full-thickness cartilage defects, displaced fractures and extensor mechanism ruptures.

  • What does the specialist team look like?

    A modern knee MDT typically includes a knee surgeon, a sports and exercise medicine physician, a specialist musculoskeletal physiotherapist and, where relevant, a radiologist. Complex multi-ligament, cartilage and paediatric injuries are increasingly managed in dedicated regional units.

  • When can I get back to sport?

    Return to sport is a criteria-based decision, not a calendar one. Benchmarks include full pain-free range, quadriceps strength within 10 percent of the other side, symmetrical hop tests and completion of a graded return-to-run and return-to-pivot programme. Rushing back is the commonest cause of re-injury and second ACL rupture.

Related content

Keep reading.

Pulse Healthcare concierge

Send us your enquiry

A concierge service for UK private healthcare. We match you with the best vetted clinics and consultants in our network - they then contact you directly.

So we can match you to the right clinician close to you.

We reply to every enquiry within 24 hours (Mon–Fri). Confidential - your details are never shared outside our vetted consultant network.