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Knee pain and sprains, a stepped plan from PRICE to reconstruction.

A twisted knee, a sudden pop, or a joint that will not settle - a clear pathway of assessment, imaging and physiotherapy-led rehab beats guesswork. For the wider hub see our knee pain guide and our knee ligament injury guide.

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

    Editorial team

    Written by our editorial team from the UK sources listed on each page.

  • 02

    Sourced from guidance

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

  • 03

    Current for 2026

    Reflects current UK practice on PRICE, physiotherapy, bracing and ligament reconstruction.

Key facts

Knee sprains at a glance.

The essentials, in plain English - what a knee sprain is, which ligaments are involved, and how it is treated in the UK today.

  • What it is

    Knee pain and sprains cover ligament and soft-tissue injuries plus general mechanical knee pain from twisting, hyperextension or overuse.

  • Ligaments involved

    MCL, LCL, ACL and PCL - graded I to III depending on how many fibres are torn and whether the joint is stable.

  • Mechanism

    Valgus force to the outer knee, varus force to the inner knee, twisting on a planted foot, or hyperextension in sport or a fall.

  • First-line care

    PRICE - protection, rest, ice, compression, elevation - plus simple analgesia and short-term NSAIDs where appropriate.

  • Foundation therapy

    Structured physiotherapy is the backbone of recovery for almost every grade of sprain and most general knee pain.

  • When surgery helps

    ACL and multi-ligament injuries with instability may need reconstruction - selective, specialist-led and always alongside rehab.

Why this guide matters

A stepped plan, not a scan-and-hope.

Knee injuries are common and mostly treatable - with a clear pathway that respects both PRICE and BASK standards. The three points below shape everything else on this page.

  • PRICE and physiotherapy first

    For most sprains, protection, rest, ice, compression and elevation - then structured physiotherapy - do the heavy lifting.

  • Image when it changes the plan

    X-ray only when the Ottawa knee rules are met. MRI when a ligament, meniscal or cartilage question needs answering.

  • Surgery is selective, not default

    ACL and multi-ligament injuries with instability may need reconstruction - specialist-led, always alongside rehab.

How the diagnosis is made

From the moment of injury to a clear plan.

The steps a UK GP, sports physician or knee surgeon will normally follow, in order - so you know what to expect and why. See the private MRI scan page for how imaging fits in.

  1. 01

    Assessing

    History and mechanism

    How the knee was hurt - twisting, valgus contact, hyperextension - plus any pop, swelling within hours and giving way.

  2. 02

    Assessing

    Red-flag screen

    Locked knee, inability to weight-bear, fever, night pain or a knee that gives way under load - each changes the plan.

  3. 03

    Assessing

    Structured examination

    Effusion, range of motion and stress tests - valgus and varus at 0 and 30 degrees, Lachman, anterior drawer and posterior sag.

  4. 04

    Confirming

    X-ray by Ottawa knee rules

    Plain films only when the rules are met - age, tenderness, inability to flex or weight-bear - to exclude a fracture.

  5. 05

    Confirming

    MRI when it will change the plan

    A private MRI scan defines ligament, meniscus and cartilage injury in detail when surgery or targeted rehab depends on it.

  6. 06

    Planning

    Musculoskeletal MDT review

    A specialist MSK team reviews complex or multi-ligament injuries and shapes a rehab and surgical pathway.

  7. 07

    Planning

    Rehab and return-to-sport plan

    Physiotherapy-led criteria, not calendar dates - strength, hop tests and confidence guide the return to activity.

Typical timeline: first assessment to a settled rehab plan in days to a few weeks.

Symptoms

What a knee sprain actually feels like.

Pain, swelling and often a sense of instability - with clues that point to which ligament is involved and how urgent things are.

  • Pain over the injured ligament

    Medial pain suggests MCL, lateral pain LCL, deep pain with a pop suggests ACL and posterior pain a PCL.

  • Swelling within hours

    A tense effusion within a few hours of injury raises concern for ACL rupture or an intra-articular fracture.

  • Instability or giving way

    A sense the knee will buckle under load points to ligament insufficiency and needs specialist assessment.

  • Locking or catching

    A true mechanical block suggests a meniscal tear or loose body and often needs MRI and orthopaedic review.

  • Bruising and tenderness

    Bruising over the joint line, condyles or ligament footprints helps localise the injury on examination.

  • Loss of full extension

    A knee that will not straighten fully may be locked by a bucket-handle meniscal tear or a large effusion.

  • Weakness and quadriceps shutdown

    Pain-driven inhibition of the quadriceps is common early and is a specific target for early physiotherapy.

  • Red flag - unable to weight-bear

    Four steps of weight-bearing is a key Ottawa knee rule threshold - failure triggers imaging and same-day review.

Treatment

How knee pain and sprains are treated in the UK.

PRICE, physiotherapy and selective bracing for most - reconstruction and MDT input for the rest. See expert physiotherapy, ACL reconstruction and steroid injection.

  • PRICE in the first 48 to 72 hours

    Protection, rest, ice, compression and elevation reduce swelling and pain and set the scene for early rehab.

  • Simple analgesia and short NSAIDs

    Paracetamol with a short course of an oral or topical NSAID where safe - reviewed rather than left open-ended.

  • Physiotherapy-led rehabilitation

    The backbone of recovery - see our spinal physiotherapy guide for how expert-led rehab is structured across regions.

  • Bracing where selective

    Hinged braces have a role in MCL injuries and post-operative ACL rehab - not routine for every sprain.

  • Steroid injection in selected cases

    A targeted steroid injection can settle a stubborn inflammatory flare and unlock rehabilitation.

  • Ligament reconstruction

    ACL and multi-ligament injuries with instability are considered for reconstruction - specialist commissioned and always paired with rehab.

  • MDT specialist input

    A BASK-aligned musculoskeletal MDT coordinates imaging, injections, surgery and return-to-sport criteria.

  • Return-to-activity criteria

    Strength, single-leg hop symmetry and confidence tests - not the calendar - decide when to return to sport.

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 examination and can tell you which parts apply to you. If in doubt, get seen.

  • NICE. Sprains and strains: guidance and clinical knowledge summaries.

  • British Association for Surgery of the Knee (BASK). Standards for knee ligament and meniscal care.

  • Royal College of Emergency Medicine. Ottawa knee rules for imaging.

  • Chartered Society of Physiotherapy. Guidance on musculoskeletal rehabilitation.

Red flags

When a knee injury needs urgent attention.

Most knee sprains settle with PRICE and rehab. These are the situations that will not - and where imaging or a specialist review should not wait.

  • Unable to weight-bear

    Four steps of weight-bearing is the Ottawa threshold - failure or a locked knee needs same-day assessment.

  • Locked knee

    A true mechanical block to full extension suggests a bucket-handle meniscal tear or loose body - urgent orthopaedics.

  • Tense effusion within hours

    A rapid, tense swelling raises concern for ACL rupture or an intra-articular fracture and warrants imaging.

  • Multi-ligament instability

    More than one ligament involved - especially with vascular concern - is an emergency and needs specialist knee input.

  • Suspected knee dislocation

    A dislocated or spontaneously reduced knee needs urgent vascular and neurological review in hospital.

  • Fever, warmth or systemic upset

    A hot, swollen, painful knee with fever is septic arthritis until proven otherwise - urgent aspiration.

  • Night pain or unexplained weight loss

    Pain that wakes from sleep, or systemic features, deserves a broader workup rather than a purely musculoskeletal one.

  • Neurovascular deficit

    Any change in pulses, sensation or foot movement after a knee injury needs immediate hospital assessment.

  • Failure to progress with rehab

    A knee that plateaus despite good physiotherapy deserves a specialist opinion and often an MRI.

Living with it

A treatable injury, with a clear ladder.

Four things that make the biggest difference day to day - early loading, trust in the plan, sensible bracing and objective return-to-sport criteria.

A quiet reminder

Rehab is a habit, not an event.

Steady, guided work over weeks and months builds a stronger knee than a heroic fortnight ever will.

  1. 01 Load

    Move early, within tolerance

    Prolonged rest weakens the quadriceps. Early, guided loading protects tendons, cartilage and confidence.

  2. 02 Rehab

    Trust the physiotherapy plan

    Progress is measured in strength and control, not weeks. A structured plan beats scattered exercises.

  3. 03 Bracing

    Use braces with intent

    Braces are helpful for MCL healing and post-operative ACL rehab - not a long-term substitute for strength.

  4. 04 Return

    Meet the criteria before sport

    Symmetrical strength, hop tests and confidence - not the calendar - decide when to return to pivoting sport.

Frequently asked

Everything we get asked about knee sprains.

Quick answers on imaging, healing times, physiotherapy and when reconstruction is needed.

  • What is a knee sprain?

    A knee sprain is a stretch or tear of one of the four main ligaments - MCL, LCL, ACL or PCL - graded I to III by how many fibres are torn and whether the joint is unstable. Mechanisms include valgus or varus force, twisting on a planted foot and hyperextension. See our knee ligament injury guide for detail on each ligament.

  • How is a knee sprain different from other knee pain?

    A sprain is a specific ligament injury with a mechanism, tenderness over the ligament and, in higher grades, instability. General knee pain covers cartilage, meniscal, tendon and arthritic causes - many overlap. Our knee pain hub is the starting point when the picture is not clearly ligamentous.

  • Do I need an X-ray or MRI?

    Not always. UK practice uses the Ottawa knee rules to decide when a plain X-ray is needed to exclude fracture. MRI is reserved for injuries where the result will change management - suspected ligament, meniscal or cartilage injury - and is where a private MRI scan is genuinely useful.

  • How long does a knee sprain take to heal?

    Grade I MCL and LCL sprains often settle within two to four weeks with PRICE and physiotherapy. Higher-grade injuries take longer. ACL and multi-ligament injuries that need reconstruction usually take nine to twelve months of structured rehabilitation before returning to pivoting sport.

  • When is surgery needed?

    Isolated MCL sprains almost always heal without surgery. ACL rupture with instability, multi-ligament injury and some PCL and posterolateral corner injuries are considered for reconstruction - specialist commissioned and always paired with rehab. See our knee ligament injury guide and the ACL reconstruction treatment page.

  • Which specialists look after knee injuries?

    A musculoskeletal team - GP or sports and exercise medicine doctor, physiotherapist and, where needed, a knee-fellowship-trained orthopaedic surgeon aligned to BASK standards. Imaging, injections and surgery are coordinated so that rehab and return-to-sport criteria stay central.

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