Red Flags After Surgery — When to Act Fast

Part of The Joint Replacement Guide — Phase 5: Recovery and Rehabilitation · Article 34 of 44 · Hip & Knee

Key Points

Most patients recover without a serious complication, but recognising important warning signs helps you obtain treatment promptly.
Call 999 for severe breathlessness, chest pain, collapse, suspected severe infection, or a serious injury or joint deformity that makes it unsafe to move.
Contact your surgical team, an urgent GP service or NHS 111 promptly about possible wound infection, persistent wound leakage or symptoms of a blood clot in the leg.
Normal postoperative pain, warmth and swelling should generally improve over time; symptoms that are new, increasing, disproportionate or accompanied by feeling unwell need assessment.
Do not wait for a routine follow-up appointment if you are concerned about a possible complication.

Call 999 Now If You Have

Call 999 for any of the following:

severe or sudden difficulty breathing
chest or upper-back pain, particularly if it is worse when breathing in
collapse, fainting or being difficult to wake
a very fast heartbeat accompanied by breathlessness, chest pain or feeling faint
sudden confusion, slurred speech or not making sense
blue, grey, very pale or blotchy skin
sudden severe hip or knee pain with an obvious deformity or inability to move safely
severe uncontrolled bleeding
a serious fall followed by deformity, severe pain or inability to get up safely.

These symptoms may indicate a pulmonary embolism, sepsis, fracture, dislocation or another medical emergency.[1–6]

Do not drive yourself to hospital. The 999 call handler will assess the situation and advise whether an ambulance or another form of emergency care is appropriate.

Possible Wound or Joint Infection

Some pain, swelling, warmth and bruising are expected after joint replacement. The concern is when these features are worsening rather than improving, appear after an initial period of recovery, or occur alongside wound changes or feeling unwell.

Contact your surgical team, an urgent GP service or NHS 111 promptly if you develop:

increasing or spreading redness around the wound
increasing warmth, swelling or pain
new or increasing wound discharge
pus or an unpleasant smell
a wound that continues to leak or begins leaking again
opening of the wound edges
fever, chills or feeling hot, cold or shivery
increasing joint pain after a period of improvement
feeling generally unwell without another clear explanation.[1,2]

Persistent wound leakage deserves prompt surgical advice even if you do not have a fever or severe pain. A temperature is not present in every infection, and infection cannot be ruled out simply because one particular symptom is absent.

Tell any clinician assessing you that you have recently had a joint replacement. Do not take leftover antibiotics or someone else’s medication; treatment should be selected after appropriate clinical assessment.

Possible Blood Clot in the Leg — DVT

Pain and swelling can be part of normal recovery, so it is not always possible to distinguish a deep vein thrombosis (DVT) by appearance alone.

Seek urgent same-day advice from your surgical team, urgent GP service or NHS 111 if you develop:

new or noticeably increasing swelling in one leg
throbbing, cramping or otherwise unexplained pain in the calf or thigh
skin that is unusually warm or becomes red, blue or darker
swollen or tender surface veins
calf pain or swelling that appears disproportionate to the rest of your recovery.[3]

A DVT does not always cause every one of these symptoms. Taking aspirin or another blood-thinning medicine reduces risk but does not completely rule out a clot. Continue prescribed medication unless a clinician tells you otherwise.

Possible Blood Clot in the Lung — Pulmonary Embolism

A pulmonary embolism occurs when a clot blocks a blood vessel in the lungs. It can be life-threatening and requires urgent assessment.

Call 999 if you have:

severe or sudden breathlessness
chest or upper-back pain
a very rapid heartbeat
collapse or fainting
symptoms of DVT together with breathlessness or chest pain.[3,4]

Sudden breathing difficulty or coughing up blood also requires urgent medical assessment. If symptoms are severe, worsening or accompanied by chest pain, faintness or a rapid heartbeat, call 999 rather than attempting to travel independently.[4]

Possible Hip Dislocation

A dislocated hip replacement usually causes sudden, severe pain and loss of normal function. The leg may appear shortened, turned or held in an unusual position, although an obvious deformity is not always present.

Seek emergency assessment if you develop:

sudden severe hip or groin pain
inability to stand or bear weight
inability to move the hip normally
a new obvious change in the position, rotation or apparent length of the leg.

Do not try to stand repeatedly, force the leg into a different position or manipulate the hip back into place. If you cannot move safely or the pain or deformity is severe, call 999.

Possible Fracture Around the Implant

A fracture can occur around a hip or knee replacement, most often following a fall or other significant injury. Occasionally, weakened bone can fracture with less obvious trauma.

Warning signs include:

sudden severe pain after a fall, twist or impact
inability to bear weight
a new deformity or shortening of the limb
rapidly increasing swelling or bruising
pain that is markedly different from your usual postoperative discomfort.

Do not continue trying to walk on the limb. Call 999 if there is deformity, severe pain, loss of feeling or circulation, or if you cannot get up or travel safely. Otherwise, obtain urgent assessment through your local emergency service.

New Numbness, Weakness or Circulation Changes

A small patch of altered sensation around the scar can be expected, particularly after knee replacement. This is different from new or worsening weakness or loss of sensation affecting the leg or foot.

Seek urgent advice if you develop:

new difficulty lifting or moving the foot
increasing numbness or weakness
a foot that becomes unusually cold, pale, blue or severely swollen
severe pain accompanied by increasing tightness or altered sensation.

Sudden weakness affecting one side of the body, facial drooping, speech difficulty or confusion may indicate a stroke and requires an immediate 999 call.

Uncontrolled Pain, Bleeding or Medication Problems

Contact your team urgently if pain is severe, continues to worsen or remains uncontrolled despite taking the prescribed medication correctly.

Obtain urgent advice for:

bleeding that repeatedly soaks through the dressing
vomiting that prevents you taking essential medication or fluids
black stools, vomiting blood or other significant bleeding while taking blood-thinning medication
a widespread rash or swelling after taking medication.

Call 999 for severe bleeding, difficulty breathing, swelling of the lips, mouth, tongue or throat, collapse, or another suspected severe allergic reaction.

Signs of Severe Infection or Sepsis

An infection can occasionally trigger a dangerous whole-body response called sepsis. Call 999 if someone with a possible infection becomes severely unwell, particularly with:

new confusion or slurred speech
very fast or difficult breathing
blue, pale or blotchy skin
extreme shivering or severe muscle pain
collapse, marked drowsiness or difficulty waking
a sense that something is seriously wrong.[5]

Do not wait for every symptom to appear.

Who to Contact

For concerns that are urgent but not immediately life-threatening, use the surgical contact number provided at discharge. Depending on your local arrangements, you can also contact your GP’s urgent service or NHS 111.

When seeking help, explain:

which joint was replaced
the date of surgery
when the new symptoms began
whether they are improving or worsening
any medicines you are taking, particularly blood-thinning medication
whether you have a temperature, wound leakage, breathlessness or calf swelling.

If you are uncertain whether a situation is an emergency, NHS 111 can assess your symptoms. Call 999 if the person is severely unwell, has serious breathing difficulty, chest pain, has collapsed or cannot be moved safely.[6]

In More Depth

No individual symptom confirms or excludes a postoperative complication. For example, warmth and swelling can be normal after surgery but can also occur with infection or DVT. Conversely, a serious infection does not always cause a high temperature, and a blood clot may not produce every classic symptom.

The purpose of this guidance is therefore not to ask you to diagnose yourself. It is to help you recognise when a change falls outside the expected direction of recovery and requires professional assessment. Prompt contact is appropriate when symptoms are new, worsening, disproportionate or accompanied by feeling systemically unwell.

This article provides general safety information and does not replace individual clinical advice. Follow the emergency and discharge instructions provided by your own hospital. If you are currently experiencing a potentially life-threatening symptom, call 999 now.

References

NHS. Complications of a hip replacement. Available at: https://www.nhs.uk/tests-and-treatments/hip-replacement/complications-of-a-hip-replacement/
NHS. Complications of a knee replacement. Available at: https://www.nhs.uk/tests-and-treatments/knee-replacement/complications/
NHS. DVT (deep vein thrombosis). Available at: https://www.nhs.uk/conditions/deep-vein-thrombosis-dvt/
NHS. Pulmonary embolism. Available at: https://www.nhs.uk/conditions/pulmonary-embolism/
NHS. Sepsis. Available at: https://www.nhs.uk/conditions/sepsis/
NHS. When to call 999. Available at: https://www.nhs.uk/nhs-services/urgent-and-emergency-care-services/when-to-call-999/

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