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Health condition · Clinically reviewed

Osteochondral defects, from stable lesions to surgical repair.

Damage to the cartilage and bone beneath it, most often in the knee, ankle or elbow. Getting the lesion staged properly shapes everything that follows.

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, orthopaedic sports medicine and peer-reviewed sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK practice including MRI staging, microfracture and osteochondral grafting techniques.

Key facts

Osteochondral defects at a glance.

The essentials, in plain English - what it is, where it happens, and how it’s treated in the UK today.

  • What it is

    Damage to both the articular cartilage and the underlying subchondral bone at a joint surface - not cartilage injury alone.

  • Common sites

    The knee (femoral condyle), ankle (talus) and elbow (capitellum) are affected most often.

  • Causes

    Acute impact trauma, repetitive microtrauma, or a sequela of osteochondritis dissecans in younger patients.

  • First-line imaging

    X-ray screens for obvious bony change - MRI is the definitive test for lesion size, stability and bone involvement.

  • Small stable lesions

    Often managed conservatively, particularly in younger patients with open growth plates.

  • Larger defects

    May need microfracture, osteochondral grafting or autologous chondrocyte implantation under a specialist MDT.

Why this guide matters

Staging the lesion decides the plan.

Osteochondral defects range from a small stable patch to a loose fragment causing locking. The three points below shape everything else on this page.

  • MRI is the deciding test

    Size, depth, and stability on MRI - not just symptoms - determine whether conservative care or surgery is right.

  • Bone is involved, not just cartilage

    The subchondral bone beneath the cartilage is damaged too, which is why simple cartilage-only treatments are not always enough.

  • Younger patients often heal without surgery

    Open growth plates give smaller, stable lesions a real chance of healing with activity modification and physiotherapy alone.

How the diagnosis is made

From first pain to a clear plan.

The steps a UK GP, orthopaedic surgeon or sports medicine specialist will normally follow, in order - so you know what to expect and why.

  1. 01

    Assessing

    History and mechanism

    A single impact injury, twisting trauma, or months of joint pain and swelling with no clear injury points the way.

  2. 02

    Assessing

    Joint examination

    Effusion, tenderness over the affected surface, reduced range of movement, and any locking or catching on movement.

  3. 03

    Assessing

    Plain X-ray

    A quick first screen - can show an obvious osteochondral fragment or subtle subchondral irregularity, but often looks normal.

  4. 04

    Confirming

    MRI of the joint

    The key investigation - characterises cartilage loss, subchondral bone oedema, and whether the fragment is stable or loose.

  5. 05

    Confirming

    Staging the lesion

    Size, depth and stability on MRI guide whether conservative care, surgery, or specialist referral is the right next step.

  6. 06

    Preparing

    Orthopaedic sports medicine referral

    Larger, unstable, or symptomatic lesions - especially with mechanical symptoms - warrant a specialist opinion.

  7. 07

    Preparing

    Arthroscopy if needed

    Direct visualisation and formal staging, often combined with treatment, when imaging alone leaves the picture unclear.

Typical timeline: a first visit to a settled plan in a few weeks, once MRI results are back.

Symptoms

What an osteochondral defect actually feels like.

Deep, activity-related joint pain, swelling and - if a fragment is loose - mechanical symptoms. The features below help make sense of what you’re feeling.

  • Deep joint pain

    Often described as coming from within the joint, worse with weight-bearing or activity that loads the affected surface.

  • Swelling

    Intermittent or persistent effusion, particularly after activity or a twisting movement.

  • Locking

    The joint suddenly catches and cannot move through its full range - suggests a loose fragment.

  • Catching sensation

    A grinding or catching feeling during movement, often intermittent rather than constant.

  • Giving way

    The joint feels unstable or buckles unexpectedly, particularly on uneven ground or stairs.

  • Reduced range of motion

    Stiffness or a mechanical block to full flexion or extension of the affected joint.

  • Site-specific patterns

    Knee lesions often affect the medial femoral condyle - ankle lesions the talar dome after an inversion injury.

  • Red flag - true locking episodes

    A joint that genuinely locks and needs manipulation to free suggests a loose osteochondral fragment needing urgent assessment.

Treatment

How osteochondral defects are treated in the UK.

Conservative care first for small stable lesions, then microfracture, grafting or chondrocyte implantation for larger or unresponsive defects - all under a specialist sports medicine MDT.

  • Activity modification

    Reducing load on the joint, offloading, and avoiding high-impact or pivoting activity while the lesion settles.

  • Physiotherapy

    Strengthening surrounding muscles, restoring range of motion, and correcting movement patterns that overload the joint.

  • Analgesia

    Simple pain relief and anti-inflammatories to manage symptoms during conservative management.

  • Microfracture surgery

    Small perforations in the subchondral bone stimulate a fibrocartilage repair response - suited to small-to-moderate defects.

  • Osteochondral autograft

    Transplanting a plug of healthy cartilage and bone from a lesser-loaded area of the same joint into the defect.

  • Osteochondral allograft

    Donor cartilage and bone used for larger defects where autograft tissue is insufficient.

  • Autologous chondrocyte implantation

    Cartilage cells are grown from a biopsy and reimplanted - reserved for select, larger, or previously treated defects.

  • Addressing underlying instability

    For example, ankle ligament reconstruction where chronic instability is driving repeated talar dome injury.

What this guide is based on

The sources behind every claim on this page.

UK national guidance and specialist orthopaedic 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 or orthopaedic specialist knows your joint and history and can tell you which parts apply to you. If in doubt, get seen.

  • NICE. Guidance on joint pain assessment and referral pathways.

  • British Orthopaedic Sports Trauma and Arthroscopy Association (BOSTAA). Cartilage and osteochondral lesion guidance.

  • International Cartilage Repair Society (ICRS). Classification and management of osteochondral lesions.

  • British Journal of Sports Medicine. Evidence reviews on cartilage repair techniques.

Red flags

When an osteochondral defect needs urgent attention.

Most lesions can be assessed and managed in a structured way through primary and secondary care. These are the situations that need faster review.

  • True mechanical locking

    A joint stuck and unable to move suggests a loose osteochondral fragment - needs prompt orthopaedic assessment.

  • Large or unstable lesion on MRI

    Bigger, detached, or fluid-lined fragments carry a higher risk of progression and usually need surgical opinion.

  • Progressive joint effusion

    Worsening swelling despite rest points to ongoing joint surface damage rather than a settling injury.

  • Skeletally immature patients with instability

    Open growth plates change management and prognosis - these cases need paediatric or young-adult orthopaedic input.

  • Failure of conservative management

    No improvement after an adequate trial of activity modification and physiotherapy warrants specialist reassessment.

  • Recurrent instability after ankle sprain

    Repeated ankle sprains with ongoing symptoms should prompt imaging for an associated talar dome lesion.

  • Signs of early osteoarthritis

    Progressive joint space narrowing on imaging suggests the defect is driving secondary degenerative change.

  • Post-traumatic acute severe pain

    Sudden, severe pain after a significant impact injury needs urgent imaging to exclude a large osteochondral fracture.

Living with it

A treatable joint condition, with a clear pathway.

Four things that make the biggest difference day to day - respecting load, keeping the muscles strong, watching for mechanical symptoms and staying on top of follow-up.

A quiet reminder

Progress is measured in weeks, not days.

Cartilage and bone heal slowly - steady, guided progress protects the joint far better than rushing back too soon.

  1. 01 Load

    Respect load limits

    Build activity back up gradually and avoid returning to high-impact sport before the joint is ready.

  2. 02 Strength

    Keep the muscles working

    Physiotherapy-guided strengthening protects the joint surface and supports recovery, whatever the treatment path.

  3. 03 Monitor

    Watch for mechanical symptoms

    New locking, catching or giving way after a period of improvement is worth reporting promptly.

  4. 04 Follow-up

    Keep review appointments

    Repeat imaging and clinical review track healing and catch lesions that are not responding as expected.

Frequently asked

Everything we get asked about osteochondral defects.

Quick answers on diagnosis, imaging, microfracture and when a graft is needed.

  • What is an osteochondral defect?

    It is damage to both the articular cartilage and the underlying subchondral bone at a joint surface, most often in the knee, ankle or elbow. It differs from a cartilage-only injury because the bone beneath the cartilage is also affected.

  • Is this the same as osteochondritis dissecans?

    They are related but not identical. Osteochondritis dissecans is a specific condition, often in younger patients, where a piece of bone and cartilage can separate from the joint surface - it can lead to an osteochondral defect if the fragment becomes unstable or detaches.

  • Why is MRI used rather than just an X-ray?

    X-ray gives a quick initial screen but often misses cartilage detail. MRI is far better at showing the size and stability of the lesion, subchondral bone involvement, and whether a fragment is loose - all of which guide treatment.

  • Can a small osteochondral defect heal without surgery?

    Yes - smaller, stable lesions, particularly in younger patients with open growth plates, often respond well to activity modification, physiotherapy and analgesia without surgery.

  • What does microfracture surgery involve?

    Small perforations are made in the exposed subchondral bone to trigger bleeding and a healing response, forming fibrocartilage that fills the defect. It suits small-to-moderate lesions and is usually done arthroscopically.

  • When would I need a graft rather than microfracture?

    Larger defects, or those that have failed microfracture, may need osteochondral autograft or allograft transplantation, or in select cases autologous chondrocyte implantation, to restore a durable joint surface.

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