Plaster cast and splinting
Putting a hard cast or a supportive splint on an injured limb to hold a broken bone or bad sprain still so it can heal.
✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review
In short
- A cast or splint holds a broken bone or bad injury still so it can heal — it doesn't 'fix' the bone, your body does that over weeks.
- A splint is often used first to allow for swelling; a full cast may follow once swelling settles.
- Keep the limb raised early on, keep the cast dry, and move the joints that aren't covered — but never push anything down inside the cast.
- Severe pain, numbness, tingling or pale/blue/cold fingers or toes can mean the cast is too tight — this is urgent, go back to the cast clinic or A&E.
A plain-English summary. The detail — including risks and recovery — is below.
At a glance
A general guide. Your specialist will give you advice for your situation.
Holds a broken bone still so it can heal in a good position.
A cast alone is not enough for unstable or badly displaced fractures, which may need surgery.
Swelling is at its worst. Keep the limb raised above heart level as much as possible, rest, and use prescribed pain relief. Move the fingers or toes and...
Written warning-sign advice and a 24-hour contact route for a too-tight cast.
Swelling is at its worst. Keep the limb raised above heart level as much as possible, rest, and use prescribed...
Pain settles. Keep the cast dry and clean, keep moving the free joints, and attend any fracture clinic checks. A...
Many casts stay on for around 4–8 weeks depending on the injury. The skin underneath is often dry, flaky and the...
It takes time to regain full movement and strength. Physiotherapy or gentle exercises are often advised, and full...
What is a plaster cast or splint?
A cast or splint holds an injured part of the body still so it can heal. It is used for broken bones (fractures), some bad sprains, and after certain operations.
A cast goes all the way around the limb and sets hard (made of plaster of Paris or, more often now, lightweight fibreglass). A splint, or 'backslab', is a hard support along only part of the limb, held with a bandage. A splint is often used first, straight after an injury, because it leaves room for swelling; a full cast may be applied once the swelling has settled.
Before a cast goes on, a broken bone sometimes needs to be put back into a better position (this is called reduction), which may be done with strong pain relief or sedation.
Most fractures held in a cast heal well over a number of weeks. The exact time depends on which bone is broken and on you — wrist and hand breaks often heal faster than leg breaks. The most important safety point is that a cast must never become too tight: severe pain, numbness, tingling, or fingers or toes that turn pale, blue or cold need urgent attention.
Types, options & approaches
There may be different ways to do this. The right approach depends on the clinical question and your circumstances.
Splint (backslab) vs full cast
| Splint / backslab | Full cast | |
|---|---|---|
| Covers | One side of the limb | All the way around |
| Allows swelling? | Yes | Less room — risk if too tight |
| When used | Soon after injury | Once swelling settles |
| Support | Good, temporary | Firmer, longer-term |
| Adjustable | Easier to loosen | Needs splitting if too tight |
Early after an injury, a splint is often safer because swelling can make a full cast too tight. Your clinician decides the right one for your injury and stage.
Preparing for your procedure
- Have the injury assessed and, usually, X-rayed first to confirm the break and its position.
- Tell the team about diabetes, poor circulation, nerve problems or skin conditions, as these affect cast safety and healing.
- Remove rings, bracelets or a watch from an injured arm before it swells.
- Arrange a lift home — you won't be able to drive with a cast on a driving limb, and shouldn't drive after sedation.
- Ask whether you'll have a splint first and a cast later, and when you'll be reviewed.
- Plan for practical help at home, especially with a leg cast or a dominant-hand injury.
What happens
The team checks the injury and usually arranges an X-ray. If a broken bone is out of position, it may be gently put back (reduced), often with strong pain relief, gas-and-air or sedation; you'll be told what to expect.
A soft layer is wrapped around the limb to protect the skin, then the plaster or fibreglass is applied and moulded into shape. Plaster of Paris is left to dry naturally. For a fresh injury, a backslab splint is often used first so the limb can swell safely.
Before you leave, the team checks that your fingers or toes are warm, pink and have normal feeling and movement, and gives you advice on raising the limb, keeping the cast dry, and the warning signs of a cast that is too tight. You'll be told when to come back to the fracture clinic, and a follow-up X-ray is often arranged to check the bone is healing in a good position.
Is this procedure right for me?
A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.
May not be suitable if…
- A cast alone is not enough for unstable or badly displaced fractures, which may need surgery.
- A circumferential cast applied too early on a very swollen limb can become dangerously tight — a splint is safer first.
- Open fractures (bone through the skin) and suspected back, neck or pelvis injuries need emergency hospital care, not a routine cast.
- People with poor circulation, diabetes or fragile skin need extra caution and close monitoring.
Delay or rearrange if…
- If the limb is very swollen, a full cast may be delayed and a splint used until swelling settles.
- An open wound or skin infection over the fracture needs treating and assessing first.
- Signs of serious injury — severe deformity, loss of pulse or sensation — need urgent assessment before casting.
- Suspected compartment syndrome must be dealt with as an emergency, not splinted and sent home.
Alternatives to discuss
- A removable brace or functional splint for some injuries.
- Surgery (pins, plates or screws) for unstable or displaced fractures.
- Supportive strapping or no immobilisation for some minor injuries, on advice.
- Physiotherapy-led management for certain stable injuries.
- NHS fracture clinic review rather than private care for the urgent injury.
Before you decide
Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.
What matters most to me?
Think about symptoms, daily life, work, caring responsibilities, sport, fertility, travel, appearance and anxiety — the right choice depends on your priorities, not just the medical facts.
What are all my options?
Ask about waiting, monitoring, medicines, rehabilitation, a smaller or larger procedure, a different test, NHS referral, or a second opinion where that would help.
What would make me pause?
Active infection, pregnancy, unstable medical problems, smoking, medicines that increase bleeding, poor support at home, or feeling pressured are all reasons to slow down and get tailored advice.
What happens if I do nothing today?
For some problems, waiting is safe; for others, delay can make treatment harder. A good consultation should explain the trade-off in plain English.
Comfort, sedation or contrast choices
If local anaesthetic, sedation, contrast or pain relief is used, ask what is planned, why, and what it means afterwards.
Benefits
- Holds a broken bone still so it can heal in a good position.
- Reduces pain by stopping the injured part moving.
- Protects the injury from further damage and from knocks.
- Supports a repair after some operations.
- Allows many fractures to heal without an operation.
Risks & complications
- Aching, stiffness and muscle weakness in the limb that's held still.
- Itchy or dry skin under the cast.
- Swelling early on, which is why raising the limb matters.
- Joints above and below the cast feeling stiff.
- The cast becoming too loose as swelling goes down, or too tight if swelling increases, needing it changed or split.
- Pressure sores or rubbing where the cast presses on the skin.
- A skin infection, especially if the cast gets wet or something is pushed inside it.
- A delayed or poorly aligned bone healing, sometimes needing further treatment.
- Compartment syndrome — a dangerous build-up of pressure causing severe, worsening pain, numbness and tightness, which is an emergency.
- A blood clot in the leg (DVT) or, rarely, the lung, more of a concern with leg injuries and reduced movement.
- Lasting stiffness or nerve problems.
The most important risk is a cast that becomes too tight, which can cut off blood supply or press on nerves — and, rarely, compartment syndrome. This is why the warning signs matter and must never be ignored. Ask the team exactly what to watch for, how to raise the limb, and who to contact day or night.
Published figures to discuss
Most casts and splints are uncomplicated, but rates of problems such as poor healing, stiffness or skin issues vary widely depending on the fracture, the bone involved, the patient's health and how the cast is cared for. Serious complications like compartment syndrome are rare. We avoid quoting invented percentages and describe risks qualitatively.
| Figure | Reported range | How to interpret it | Source / confidence |
|---|---|---|---|
| Cast too tight or swelling causing pressure problems | Uncommon but urgent | Increasing pain, numbness, blue fingers/toes, inability to move digits or pain not helped by elevation needs same-day review. | Guide sourcesClinical context |
| Skin pressure sore under a cast | Uncommon, higher with frail skin, neuropathy or poorly fitting casts | Burning pain, smell, wetness or rubbing should not be ignored. | Guide sourcesClinical context |
| Venous thromboembolism with lower-limb immobilisation | Uncommon but clinically important | Risk assessment should consider age, previous clot, cancer, hormones, pregnancy, obesity and weight-bearing status. | NHS — Broken arm or wristnhs.ukSource-linked context |
| Joint stiffness and muscle loss | Common after immobilisation | Splints should immobilise what needs protecting while encouraging safe movement of free joints. | Guide sourcesClinical context |
These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.
What happens afterwards
Recovery is really about the injury healing underneath the cast over weeks, then regaining movement and strength once the cast comes off. The cast itself just holds things still while your body does the healing.
- Stiffness and muscle wasting in the limb that was held still.
- Dry, flaky, pale skin when the cast comes off — wash gently and moisturise.
- Aching as you start using the limb again.
- The limb feeling weaker and thinner than the other side for a while.
Aftercare
- Keep the limb raised, especially in the first few days, to reduce swelling.
- Keep a plaster cast dry; use a proper waterproof cover for washing unless told it's a waterproof cast.
- Move the joints that aren't covered (such as fingers or toes) regularly to reduce stiffness and swelling.
- Never push anything (knitting needles, pens) inside the cast to scratch — it can damage the skin and cause infection.
- Do not cut, alter or remove the cast yourself.
- Take pain relief as advised and watch for the warning signs of a too-tight cast.
- Attend all fracture clinic appointments and any physiotherapy.
- Sling or way to keep the limb raised
- Waterproof cover for washing
- Pain relief at home
- Lift home and help with daily tasks arranged
- Fracture clinic appointment date noted
- Cast clinic / A&E number saved for warning signs
⚠ Get urgent help if…
- Severe or worsening pain not eased by your usual pain relief — this can be compartment syndrome, an emergency.
- Numbness, pins and needles, or loss of feeling in the fingers or toes.
- Fingers or toes that turn pale, blue, white or cold, or that you can't move.
- The cast feeling far too tight, or much too loose so the bone isn't supported.
- A bad smell, discharge or new wetness from inside the cast (possible infection).
- A burning, rubbing or sore spot under the cast.
- Calf pain, swelling or breathlessness — possible blood clot — seek urgent help.
Who to contact: your clinician, clinic or test provider first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.
General guidance — it doesn't replace the specific advice your specialist gives you.
Results & realistic expectations
A good result is the bone or injury healing in a good position with the limb working well afterwards. The cast supports the injury while your body heals it, and a follow-up X-ray often confirms the bone is mending as expected.
A cast cannot guarantee a bone heals perfectly. Some fractures heal slowly, in a slightly off position, or occasionally not at all, and may then need surgery or further treatment. Stiffness and weakness after the cast comes off are common and usually improve with time and exercises, but full recovery can take longer than the cast was on.
Once a fracture has fully healed it is usually as strong as before, though it can take months for movement, strength and confidence to return completely. A few people have lasting stiffness, aching or, with joint injuries, a higher chance of arthritis later. Following the rehabilitation advice gives the best long-term result.
Related tests, treatments or support
Casting is often combined with an X-ray to confirm the diagnosis and check alignment, with pain relief or sedation if the bone needs setting, and with physiotherapy afterwards to restore movement. Some fractures are first fixed with surgery (pins, plates or screws) and then protected in a cast or splint.
Follow-up & long-term care
You will usually be seen in a fracture clinic, often within a week or so, to check the cast and review X-rays. Further appointments monitor healing, and the cast is removed when the bone is strong enough. You should be told who to contact urgently if you have any warning signs in the meantime.
- Keep the cast clean and dry throughout.
- Continue moving uncovered joints to limit stiffness.
- Attend follow-up X-rays and clinic checks.
- Do the exercises advised once the cast is off to rebuild strength.
- Report any new pain, rubbing or looseness promptly.
Repeat, follow-on and what comes next
- A cast often needs changing — for example a splint swapped for a full cast, or a cast re-applied if it loosens.
- Some fractures heal in a poor position or slowly and need surgery or further treatment.
- Repeat X-rays may show the bone has shifted, requiring re-setting.
Ask what happens if the result is unclear or needs repeating, and what is included if further tests or follow-up are needed.
What good aftercare looks like
- Written warning-sign advice and a 24-hour contact route for a too-tight cast.
- Clear instructions on raising the limb, keeping the cast dry and moving free joints.
- Booked fracture clinic follow-up with repeat X-rays as needed.
- A rehabilitation or physiotherapy plan for after cast removal.
- Specific guidance for higher-risk patients (diabetes, poor circulation).
What affects the cost
Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:
- Whether care is NHS urgent care or a private orthopaedic clinic, which charges consultation and procedure fees.
- X-rays and any other imaging needed to assess the fracture.
- The type of cast or splint and materials used.
- Whether the bone needs setting (reduction), and whether sedation or anaesthetic is involved.
- Whether surgery is needed to fix the fracture before casting.
- Follow-up fracture clinic appointments and repeat X-rays.
- Physiotherapy or rehabilitation after the cast comes off.
- The consultation and cast/splint fee and what it includes.
- Cost of X-rays and follow-up imaging.
- Whether reduction, sedation or surgery would be extra.
- How many follow-up appointments are included.
- Whether physiotherapy after cast removal is covered.
- What happens, and what it costs, if the bone doesn't heal well and needs further treatment.
On the NHS? Casts and splints for fractures are routinely provided free by the NHS through A&E, minor injuries units and fracture clinics. Private orthopaedic care may be used for faster specialist review or choice of surgeon, but the urgent injury itself is an NHS service.
You're entitled to your total cost in writing — including reports, follow-up and what happens if the result is inconclusive — before you decide.
Consent traps and marketing red flags
These are not small details. They are often where patients lose choice, time to reflect, or realistic expectations.
Consent traps
- No clear, written warning about the signs of a too-tight cast and who to contact.
- Not explaining that a splint may be needed first because of swelling.
- No advice that stiffness, weakness and a long rehabilitation are normal after the cast.
- Not mentioning the small risk of blood clots with leg injuries and reduced movement.
Marketing red flags
- Promising a 'quick fix' or guaranteed healing time regardless of the injury.
- Waterproof-cast claims without confirming it's suitable for your specific cast and injury.
- Downplaying the need for follow-up X-rays and rehabilitation.
- Suggesting a private cast avoids any risk of complications.
Choosing a specialist safely
- Check the specialist is on the GMC Specialist Register for this area.
- Make sure they work at a CQC-registered service, and look for membership of the relevant Royal College or professional body.
- You're entitled to time to consider and to have your questions answered before you agree — the specialist who looks after you should explain it, not a salesperson.
- Be wary of pressure: time-limited offers or deposits taken before you've had time to think are red flags, not bargains.
- You're entitled to your total cost in writing — including any follow-up — before you decide.
Questions to ask your medical professional
Take this to your consultation. A good specialist will welcome every one of these.
- Which bone is broken, and does it need setting or surgery, or just a cast?
- Am I getting a splint now and a cast later, and when?
- Exactly what warning signs mean my cast is too tight, and who do I call?
- How long should the cast stay on, and when are my X-ray checks?
- Will I need physiotherapy, and how long until I can drive or work?
- Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
- Will you be the specialist who carries out my procedure, and who looks after me afterwards?
- What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
- What does a realistic result look like — and what can this procedure not achieve?
- What are my options, including waiting, doing nothing for now, or choosing a different approach?
- Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
- What is the total cost in writing, including any follow-ups, and how much time do I have to decide?
Frequently asked questions
How long will I have the cast on?
Why did I get a splint first instead of a full cast?
Can I get my cast wet?
It's really itchy — can I poke something down to scratch?
What if my cast feels too tight?
Will I need physiotherapy after it comes off?
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How we made this page
Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →
Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.
Sources & standards: NHS — Broken arm or wrist NHS — Broken leg St John Ambulance — Broken bones and fractures Royal College of Emergency Medicine — Patient information NICE NG38 — Fractures (non-complex): assessment and management
Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.
Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.
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