Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.
Total hip and knee replacement indications
Musculoskeletal medicine and orthopaedics · UK scope · Sources checked 27 Aug 2026 · Clinical review pending
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Elective replacement pauses when an active threat is present
Active joint or remote infection, uncontrolled medical instability, acute fracture, severe skin compromise or an undiagnosed rapidly destructive joint changes the timing and sometimes the operation.
Action: Identify and treat sepsis, fracture, vascular or medical instability first; investigate unexplained rapid destruction and optimise active infection, skin, diabetes, anaemia and medicines through a named pathway while maintaining proportionate access to arthroplasty assessment.
Purpose and principles
Make referral and operative decisions from quality-of-life impact, failed or unsuitable non-operative care, anatomy, goals and individual risk; explain implant choices and optimisation without inequitable numerical or demographic barriers.
Joint replacement is considered when symptoms and functional loss matter enough to justify operative risk and conservative treatment no longer provides an acceptable life. Document walking, stairs, sleep, work, self-care, caring responsibilities and valued activities, plus what the person expects surgery to restore. Establish duration, progression and whether hip, spine, vascular or neurological disease contributes. A radiograph is necessary for planning but cannot by itself prove that the target joint causes the disability.
NICE osteoarthritis guidance recommends referral when pain, stiffness or reduced function substantially affects quality of life and non-surgical management is ineffective or unsuitable. The decision uses clinical assessment rather than a scoring tool. Therapeutic exercise, weight support and appropriate analgesia should have been available, but repeated low-value treatment is not a prerequisite. Severe toxicity, contraindication or inability to access an option can make non-surgical management unsuitable and should not trap the person outside referral.
Indications, selection and cautions
Quality-of-life indication
Substantial restriction of sleep, mobility, self-care, work or valued activity despite ineffective or unsuitable non-operative treatment supports referral.
Target-joint confirmation
Symptoms, examination and radiographs should align sufficiently to avoid replacing a joint when spine, vascular or regional disease is dominant.
Hip replacement anatomy
End-stage painful hip disease with restricted movement and compatible radiographs supports total replacement after risk and goal discussion.
Knee replacement anatomy
Painful compartment disease, deformity and functional loss are assessed with alignment, stability and weight-bearing views to select total or partial options.
Temporary contraindication
Active infection, unstable medical disease, ulceration or untreated anaemia triggers a named optimisation plan rather than automatic permanent exclusion.
Uncertain benefit
Diffuse pain, minimal joint findings or expectations of complete normality need diagnostic and expectation work before listing.
Red flags requiring action
A hot joint, draining sinus, persistent wound or unexplained raised inflammatory markers requires infection investigation before primary implantation.
Rapid femoral-head or tibiofemoral collapse, night pain, mass or constitutional symptoms requires malignancy, infection and osteonecrosis assessment rather than routine listing.
Assessment before treatment
01Clinical indication assessmentFirst step
Why
Measure symptom impact, goals and response or unsuitability of non-operative care.
Interpretation and limitations
Use narrative function and shared judgement rather than a mandatory numerical threshold.
02Weight-bearing radiographs
Why
Confirm compartment anatomy, deformity and templating information.
Interpretation and limitations
Structural severity informs operation but should not be used alone to accept or reject a person.
03Targeted infection screen
Why
Exclude active joint or remote infection when suggested.
Interpretation and limitations
Use examination, CRP or ESR and aspiration through the appropriate pathway; do not screen every asymptomatic joint indiscriminately.
04Preoperative blood and cardiac assessment
Why
Identify anaemia, renal dysfunction, diabetes and anaesthetic risk.
Interpretation and limitations
Results should lead to proportionate optimisation and shared risk, not unexplained cancellation.
05Perfusion and skin review
Why
Treatment approach
01ReferBase referral on impactFirst stepSymptoms substantially affect quality of life and evidence-based non-operative care is ineffective or unsuitable.+
1Confirm the likely pain-generating joint and document function, goals and previous treatment.
2Discuss replacement and continued non-operative options and refer without a numerical-score or demographic barrier.
3AlternativeObtain planning radiographs through the surgical pathway and identify urgent alternative diagnoses.
4Continue active symptom and fitness management while assessment proceeds.
02OptimiseReduce modifiable risk with ownershipThe person may benefit, but anaemia, diabetes, smoking, nutrition, skin, medicines or fitness can be improved.+
1Quantify the individual risk and agree a realistic target rather than imposing an unexplained threshold.
Regimens, contraindications and interactions
Reduces surgical-site and prosthetic-joint infection risk when combined with theatre, skin, glycaemic and wound measures.
Perioperative antimicrobial prophylaxis
Give the hospital's current primary hip or knee replacement prophylactic antibiotic at the full weight-, allergy- and renal-adjusted dose within the protocol time before incision, record administration, and repeat intra-operatively only when the specific protocol duration or blood-loss criterion is met.
Use the exact local formulary because MRSA status and immediate beta-lactam allergy change selection; therapeutic postoperative antibiotics are not routine prophylaxis and unexplained extension increases adverse effects and resistance.
Reduces postoperative deep-vein thrombosis and pulmonary embolism during the period of increased coagulation and reduced mobility.
Venous-thromboembolism prophylaxis
Prescribe the exact mechanical and pharmacological regimen from the current hospital elective-arthroplasty and NICE pathway, starting and continuing at the procedure-specific times after balancing thrombosis, neuraxial and bleeding risk.
Agent, dose and duration depend on hip versus knee surgery, renal function, body weight, bleeding, anaesthetic technique and long-term anticoagulation; document interruption and restart rather than duplicating anticoagulants.
Complications, monitoring and follow-up
Before surgery, revisit pain source, goals, consent and any change in benefit-risk balance.
Track anaemia, glucose, renal function, nutrition, smoking support, skin and infection issues through optimisation.
Document perioperative antimicrobial and thromboprophylaxis timing and reconcile anticoagulant restart.
After surgery, monitor wound, fever, neurovascular status, haemoglobin, pain, mobility and dislocation or instability signs.
Measure recovery against the person's walking, sleep, work and self-care goals and address persistent pain early.
Follow implant and revision concerns through the appropriate arthroplasty and registry pathway.
Special situations
Referral is not a radiographic prize
Quality-of-life impact and failed or unsuitable care drive referral; imaging supports anatomy and planning.
Optimisation needs a clock
A modifiable risk plan without support, ownership and a review date can become indefinite denial of treatment.
No operation is a valid choice
Shared decisions include continued non-operative care when expected benefit does not outweigh recovery and risk.
Partial knee replacement is not lesser
For suitable isolated medial disease, partial and total replacement have different advantages and both require balanced consent.
Persistent pain belongs in consent
A technically successful implant may not abolish pain, especially when pain sources and expectations were poorly aligned.
Prehabilitation starts discharge
Strength, aids, home support and medicine plans prepared before surgery shorten avoidable postoperative barriers.
Common pitfalls
01
Using a numerical score or X-ray grade as the sole gate to referral.
02
Refusing assessment solely because of BMI, age, smoking or comorbidity.
03
Listing before confirming that the target joint is the dominant pain source.
04
Describing only infection and thrombosis while omitting persistent pain, stiffness, instability and revision from consent.
05
Calling risk optimisation without providing support or a time for reassessment.
06
Stopping exercise and safe symptom control while the person waits for surgery.
Practice
Two practice questions
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Question 1 of 2
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Musculoskeletal medicine and orthopaedicsOriginal SBA
Referral threshold principle
Which clinical finding best supports referral of an adult for primary hip or knee replacement assessment under current NICE osteoarthritis guidance?
Sources and review status4 sources · checked 27 Aug 2026 · clinical review pending+
Sources
Sources and review status
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.
Do not exclude referral solely because of age, sex, smoking, comorbidity or overweight or obesity. These factors influence absolute risk and optimisation, and some may alter anaesthetic or implant choices, but blanket thresholds create inequity. Explain individual risks honestly and agree achievable optimisation: smoking cessation support, diabetes control, anaemia treatment, nutrition, weight management, skin and ulcer care, dental infection management and physical conditioning. State who provides support and when readiness is reviewed.
Confirm diagnosis and anatomy with examination and weight-bearing radiographs. For hip replacement assess hip-spine interaction, leg length, abductor function, prior surgery and deformity. For knee replacement assess alignment, range, flexion contracture, ligament stability, patellofemoral symptoms and compartment distribution. Investigate unexplained inflammatory, infective, rapidly destructive or neuropathic patterns before implantation. MRI is not routine for established end-stage osteoarthritis unless a specific alternative question persists.
Shared decision-making covers no operation, continued non-operative care and the available replacement designs. Explain likely improvement rather than promising a normal joint. Discuss pain persistence, stiffness and dissatisfaction as well as infection, bleeding, thrombosis, fracture, nerve or vessel injury, dislocation after hip replacement, instability after knee replacement, wear, loosening and revision. Explore transfusion, rehabilitation, driving, work and home support. Give accessible written information and time to reconsider.
Total hip replacement replaces both femoral head and acetabular surface. Implant fixation, bearing and surgical approach depend on bone, anatomy, age, activity, evidence and surgeon practice; marketing claims should not replace registry and guidance. Total knee replacement resurfaces all compartments selected by the implant while unicompartmental replacement treats suitable isolated compartment disease with intact relevant stabilisers. NICE asks surgeons to offer a choice of partial or total knee replacement when isolated medial disease makes both appropriate.
Preoperative assessment addresses cardiopulmonary fitness, frailty, renal function, anaemia, diabetes, nutrition, venous-thrombosis risk, anticoagulants, infection and home circumstances. Medication plans specify which anticoagulants, antiplatelets and diabetes drugs change and when they restart. Prehabilitation builds strength and prepares aids and discharge. Enhanced recovery combines multimodal analgesia, early oral intake and mobilisation, thromboprophylaxis and early recognition of bleeding, infection, dislocation, neurovascular injury and urinary or cognitive complications.
Referral does not guarantee operation, and deferral should be a shared, revisable decision. If benefit is uncertain because pain source is mixed, use targeted assessment rather than exploratory arthroplasty. If risk currently outweighs benefit, write the exact remediable factors, support and review date. Continue exercise, walking aids and safe analgesia during optimisation or waiting. Deterioration, falls, new rest pain or acute swelling requires reassessment. Outcome review includes pain, function, complications and whether the person's stated goals were achieved.
Key points
Refer when joint pain, stiffness, deformity or reduced function substantially affects quality of life and non-surgical management is ineffective or unsuitable.
Use clinical assessment and shared decision-making; do not require a numerical severity score and do not exclude referral solely because of age, sex, smoking, comorbidity, overweight or obesity.
Confirm that symptoms arise from the target joint and that reasonable education, exercise, weight support and safe medication have been offered or are unsuitable; this is not a rigid checklist that prolongs avoidable disability.
Discuss expected pain and function benefit, persistent symptoms, recovery demands, implant survival, infection, thrombosis, dislocation or instability, fracture, nerve injury, loosening and revision.
Use standard radiographs for anatomy and templating; radiographic severity supports planning but does not override the person's symptoms and goals.
For isolated medial-compartment knee osteoarthritis suitable for either operation, NICE recommends giving people a choice of partial or total knee replacement after discussing both outcomes and risks.
Optimise anaemia, diabetes, smoking, nutrition, weight, skin, dental and medication risks collaboratively and make the required target, support and review date explicit.
Critical cardiac, respiratory or metabolic instability requires coordinated optimisation, but should produce a documented plan rather than indefinite removal from care.
Poor pulses, active ulceration or major skin disease near the operative limb requires vascular or dermatological treatment to protect wound healing and infection risk.
Assess wound-healing capacity and infection route.
Interpretation and limitations
Active ulceration, severe arterial disease or skin infection needs treatment and coordinated timing.
06Additional imaging selectively
Why
Resolve occult pathology, severe deformity or mixed pain source.
Interpretation and limitations
CT, MRI or diagnostic injection answers a defined question and is not routine simply because surgery is discussed.
2
Provide the service, named clinician and review date needed to achieve it.
3Plan anticoagulant, diabetes and analgesic changes and home and rehabilitation support.
4Revisit the benefit-risk decision promptly instead of allowing indefinite optimisation limbo.
03ChooseMatch operation to anatomy and valuesDiagnosis, risk and expected benefit are sufficiently clear for consent and implant selection.+
1Discuss total hip or knee replacement benefits, persistent symptoms, complications, implant survival and revision.
2For suitable isolated medial knee disease, offer balanced choice between partial and total replacement.
3Record the person's priorities, approach and implant reasoning and perioperative prophylaxis plans.
4Deliver enhanced recovery, early mobilisation and structured surveillance for early complications.
Prehabilitation, discharge planning and expectation alignment begin before surgery; an informed decision can also be to defer replacement while maintaining active non-operative care.