Total Hip Arthroplasty Indications

Total hip arthroplasty (THA) is one of the most successful operations in modern medicine. Its primary indication is end-stage hip arthritis causing pain and disability that has failed conservative management.

Why it works. THA reliably eliminates the pain of an arthritic hip, restores function and mobility, and significantly improves quality of life, with predictable long-term outcomes from modern implants. The key is patient selection: matching the right patient to the right procedure at the right time.

History. Sir John Charnley pioneered modern THA in the 1960s with the low-friction arthroplasty, and cemented metal-on-polyethylene became the gold standard. Implants have since evolved towards modular designs, improved bearing surfaces and minimally invasive techniques. The Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR), a world-leading registry, was established in 1999.

Volume. AOANJRR 2023 data record over 50,000 primary THAs a year, an increasing trend driven by the ageing population. Bilateral THA is common: 10-15% of patients eventually need the contralateral hip replaced. The male-to-female ratio is approximately 1:1.2, osteoarthritis being slightly more common in women.

Diagnoses. The primary diagnoses behind a THA, by share:

• Osteoarthritis, primary or secondary - 85-90%
• Avascular necrosis - 5-10%
• Inflammatory arthritis (RA, AS, psoriatic arthritis) - 2-5%
• Fracture sequelae - 2-3%
• DDH and other - 1-2%

The contraindications table lists severe obesity (BMI over 40), active substance abuse and age under 50 among the relative contraindications. Are these access thresholds that disqualify a patient, or modifiable risk factors to be optimised? The modern, guideline-based answer is the latter.

Do not ration by BMI, age or smoking alone. NICE (NG226) explicitly states that access to joint replacement should not be restricted on the basis of age, sex, smoking or BMI alone; the patient should be referred when symptoms substantially affect quality of life and non-surgical care has been ineffective. Arbitrary BMI or age cut-offs are not supported by outcome evidence, deny a highly effective operation to patients who would benefit, and worsen health inequity. The absolute pain and function benefit of THA is largely preserved across BMI categories, even though the complication risk is higher.

Optimise, then share the decision. A modifiable risk factor is a target for prehabilitation, not a reason to refuse surgery. A higher BMI justifies risk optimisation, counselling and vigilant perioperative care, and the shared decision is documented rather than an arbitrary rule applied.

Selection decides the outcome. Patient selection is the single most important determinant of THA outcome. The ideal candidate:

• Is aged 50-80 years, the optimal risk-benefit balance
• Has severe symptomatic hip arthritis (pain, disability)
• Has failed an adequate conservative trial (6 months or more)
• Is motivated, with realistic expectations
• Is able to participate in rehabilitation
• Has optimised medical comorbidities
• Has social support for the postoperative period

Age at the extremes. Younger patients carry the higher lifetime revision risk set out under Contraindications. Older patients, over 80, have a higher perioperative risk but excellent implant survival if they survive surgery.

The workup runs over three visits:

Cardiac optimisation. Risk is scored with the Revised Cardiac Risk Index (RCRI), which has six predictors; recent MI, CHF, CVA, diabetes, renal insufficiency and high-risk surgery mark high risk. Refer to cardiology if the RCRI is 2 or more, and consider a stress test if the patient is symptomatic. Beta-blockers and statins are used perioperatively.

Pulmonary optimisation. In COPD, optimise bronchodilators and stop smoking. In OSA, confirm CPAP compliance and monitor perioperatively. Defer surgery until any respiratory infection has resolved, and obtain ABG and PFTs if disease is severe.

Metabolic optimisation. Poor diabetic control increases infection risk 3-fold; the HbA1c targets are below. Anaemia is investigated with iron studies, with EPO if Hb is under 110 g/L, and renal impairment calls for adjusted medications and a hydration protocol.

Dental clearance. Recent dental infection or poor dentition can lead to bacteraemia and haematogenous seeding of the prosthetic joint. The protocol:

• All patients - dental examination within 6 months of THA
• Active dental infection - treat first, then wait 6 weeks minimum
• Poor dentition, multiple caries - consider extraction and healing before THA
• Routine dental prophylaxis - per ADA guidelines, not routinely recommended for most patients; consider in the high-risk

MRSA screening and decolonisation. Carriers are identified and decolonised before surgery:

The indication. End-stage hip arthritis causing pain and functional disability that has failed adequate conservative management. It rests on three pillars:

1. Pain and disability. Pain that affects quality of life (sleep, ADLs, recreation) and limits function (walking distance, stairs, getting out of a chair), with its severity documented by PROMs (HOOS, WOMAC, Oxford Hip Score).
2. Radiographic evidence. Joint space loss, osteophytes, sclerosis and cysts confirm the diagnosis but do NOT alone indicate the need for surgery; severity on the X-ray does not correlate perfectly with symptoms.
3. Failed conservative treatment. At least 6 months of appropriate non-operative management - physiotherapy, weight loss, activity modification, analgesia (NSAIDs, paracetamol) and intra-articular injection - with the patient's compliance documented.

Absolute indications

• Severe OA with pain, disability and failed conservative treatment (the most common)
• AVN Stage III-IV, with collapse and secondary OA
• Failed previous surgery (ORIF for fracture, osteotomy) with persistent pain
• Acute femoral neck fracture in the elderly, where the decision is hemiarthroplasty versus THA (see the next section)

Relative indications

• Young patient (under 50) with severe symptoms - weigh the alternatives
• Inflammatory arthritis (RA, AS) with hip involvement
• Post-traumatic arthritis after acetabular fracture or dislocation
• DDH with secondary arthritis
• Failed hip preservation (PAO, femoral osteotomy)

By diagnosis. The underlying diagnosis changes who is offered THA, when, and how the operation is planned.

OsteoarthritisAvascular NecrosisInflammatory ArthritisPost-TraumaticDDH

Primary Osteoarthritis

Presentation. Insidious groin pain that may radiate to the thigh or knee, mechanical in character (worse with activity, better with rest), with progressive stiffness and a change in gait: antalgic, or Trendelenburg if the abductors are weak.

When to offer THA. When the patient meets these criteria:

• Pain affecting sleep or ADLs
• Walking distance limited, typically under 500m
• Oxford Hip Score under 30/48
• Failed 6 months of conservative treatment
• Motivated for surgery and rehabilitation, and understands the risks and benefits
• Medical comorbidities optimised

Primary vs Secondary OA

Primary OA = idiopathic, typically over 50 years, no clear cause. Secondary OA = identifiable cause such as DDH, AVN, SCFE, Perthes, post-traumatic. Important to distinguish because secondary OA may require specialised surgical planning (e.g., DDH needs high hip centre restoration).

Avascular Necrosis (AVN)

The patients. A younger population, average age 40-50, and often bilateral, so stage the contralateral hip. The aetiology (steroid-induced, alcohol, SCD, idiopathic) affects prognosis.

Collapse decides. Staging is under Classification; the treatment follows it:

• Stage I-II (MRI positive, X-ray normal or early changes): consider hip preservation - core decompression, free vascularised fibular grafting or bisphosphonates, avoidance of risk factors, or observation. The outcome is variable: progression may halt or continue to collapse.
• Stage III (subchondral collapse visible on X-ray, crescent sign): THA. Core decompression is no longer effective, and THA gives excellent pain relief.
• Stage IV (acetabular involvement, advanced arthritis): standard THA.

The young AVN hip. Consider the younger patient's needs: a dual-mobility bearing to reduce dislocation risk, and hard-on-hard bearings.

View larger

Inflammatory Arthritis

Rheumatoid arthritis. Bilateral hip involvement is common, and so is protrusio acetabuli (medial wall migration), which may need a structural graft. Bone quality is poor from both the disease and its medications, so cemented fixation is often preferred.

Ankylosing spondylitis. The hip is involved in 25-30% of AS patients, with severe stiffness or ankylosis. The fused spine affects positioning and increases dislocation risk, and a severe flexion contracture may need osteotomy. The risk of heterotopic ossification (HO) is very high, and prophylaxis is mandatory.

Around the operation. Management is multidisciplinary with rheumatology. Medical management with DMARDs comes first, and THA is offered if the joint is destroyed despite it. DMARD use may affect wound healing and infection risk, so perioperative immunosuppressant management is discussed (stop methotrexate, continue biologics per guidelines). Bilateral surgery is often staged.

HO Prophylaxis in AS

Ankylosing spondylitis patients have up to 70% risk of heterotopic ossification after THA. Mandatory prophylaxis: Indomethacin 75mg daily for 6 weeks OR single-dose radiation (7-8 Gy within 24 hours of surgery). Without prophylaxis, severe HO can cause ankylosis and loss of motion.

View larger

View larger

Post-Traumatic Arthritis

Indications. THA is offered when the sequelae are symptomatic:

• Failed ORIF of a femoral neck fracture (malunion, AVN, nonunion)
• Arthritis after acetabular fracture
• Arthritis after hip dislocation
• Late sequelae of SCFE or Perthes disease

Challenges. The anatomy is altered by previous hardware and malunion, and retained hardware may need removal. Bone may have been lost to the trauma or earlier surgery, the soft tissues are scarred and contracted, and the patients are young.

Planning. CT assesses bone stock and deformity. Plan the hardware removal, which may need a separate incision, consider structural grafting for bone defects, and anticipate a difficult dissection through scar. Counsel the patient about these potential challenges.

Developmental Dysplasia of Hip (DDH)

The aims. THA in DDH is a complex reconstructive procedure with two goals: restore the hip centre to its anatomic position, and achieve stable fixation. Bone deficiency, femoral anteversion and leg length inequality stand in the way. Crowe grading is under Classification.

Timing. The young patient with symptoms and no OA is treated with PAO; established OA is treated with THA and specialised planning.

Surgical considerations. Each shapes the plan:

• Acetabulum - high hip centre versus anatomic centre with structural graft
• Femur - shortening osteotomy in Crowe III-IV to avoid nerve stretch
• Specialised implants - small cups, dysplasia stems
• Templating is essential - anticipate cup size and medialisation needs

Nerve Injury Risk in DDH

In Crowe III-IV DDH with high dislocation, attempting to restore anatomic hip centre can stretch the sciatic nerve more than 4cm, causing palsy. Solution: Femoral shortening osteotomy (remove 2-4cm of proximal femur) to allow hip centre restoration without nerve stretch.

The absolute indications above and the AO Foundation guideline row (Guidelines section) both name the displaced intracapsular femoral neck fracture as a setting where arthroplasty is indicated and where the examiner expects a structured THA-versus-hemiarthroplasty decision. (Undisplaced fractures, younger patients suitable for fixation, and the internal-fixation construct itself are managed on the fracture pathway and are covered in the hip-fracture topics.)

Why arthroplasty rather than fixation in this group. A displaced (Garden III-IV) subcapital fracture in an older patient disrupts the retinacular blood supply to the femoral head, so internal fixation carries a high rate of avascular necrosis and nonunion with a heavy re-operation burden. Replacing the head at the index operation avoids that failure pathway, which is why displaced intracapsular fractures in the older patient are treated by arthroplasty rather than fixation.

View larger

View larger

Choosing between hemiarthroplasty and THA. The head must be replaced either way; the real question is whether to resurface the acetabulum as well.

In short, the fit, independent, cognitively intact older patient - especially one who already has acetabular arthritis - is the candidate for THA, which gives modestly better function and avoids the later groin pain of acetabular erosion seen when a hemiarthroplasty head articulates against native cartilage. The frail, low-demand or cognitively impaired patient is better served by hemiarthroplasty, which is quicker, carries a lower dislocation risk and is adequate for limited demand. (Unipolar versus bipolar hemiarthroplasty shows no clear functional difference - that detail belongs with the hip-fracture topics.)

View larger

Uncontrolled comorbidity. The table classes a recent MI (under 6 months) and severe uncontrolled comorbidity - CHF, COPD exacerbation, uncontrolled diabetes - as absolute, and its management column is to defer and optimise. They are absolute bars to operating while they remain uncontrolled, and the next section explains why modifiable factors such as diabetes are treated rather than used to refuse.

Bone stock and vascular supply. Inadequate bone stock covers severe osteoporosis and Paprosky Type III defects without a reconstruction plan. Peripheral vascular disease matters where healing potential is poor or there are active ulcers.

Young patients (under 50). Youth is not an absolute contraindication, but it needs careful discussion. Lifetime revision risk is high - a 50-year-old may need 2-3 revisions in a lifetime - and AOANJRR data show a higher revision burden in patients under 55. Activity levels are typically higher, increasing wear and loosening risk.

• Alternatives - hip arthroscopy, PAO, femoral osteotomy, resurfacing
• If THA is necessary - hard-on-hard bearings (ceramic-on-ceramic), dual mobility
• Counsel - revision is likely; activity restrictions; the long-term implications

Neuromuscular disease. Parkinson's disease (rigidity, bradykinesia, falls), CVA with spasticity or weakness, cerebral palsy and muscular dystrophy all carry a high dislocation risk. Mitigate it with a dual-mobility bearing, a constrained liner or a large-diameter head, and educate the patient and family about dislocation precautions. Consider whether the benefits outweigh the risks (severe pain, immobility).

The normal hip. A ball-and-socket joint with excellent stability and range of motion. The femoral head, two-thirds of a sphere, articulates with the horseshoe-shaped lunate surface of the acetabulum, and articular cartilage 2-4mm thick distributes load and allows low-friction movement. The labrum deepens the socket and creates a suction seal; the capsule is reinforced by the iliofemoral, pubofemoral and ischiofemoral ligaments.

An active disease. Osteoarthritis is more than "wear and tear". It is a disease process involving:

• Cartilage degradation by matrix metalloproteinases
• Subchondral bone change: sclerosis and cysts
• Synovial inflammation
• Osteophyte formation

The rate of progression is highly variable: some patients plateau, others progress rapidly.

Severity and symptoms. Mild disease, with joint space narrowing and early osteophytes, gives mild pain with activity and is managed with weight loss, physiotherapy and analgesia. Moderate disease, with definite narrowing, osteophytes and sclerosis, brings pain that limits activity and stiffness; injection is considered while conservative care continues. Severe disease is bone-on-bone with large osteophytes and cysts, and brings constant pain, night pain and major disability; THA is offered if conservative care has failed for 6 months or more.

History. Establish how much the hip limits the patient and what has already been tried:

• Pain - location (groin versus lateral), severity, progression
• Function - walking distance, stairs, ADLs, sleep disturbance
• Previous treatment - physiotherapy, injections, medication; duration and response
• Comorbidities - cardiac, pulmonary, diabetes, immunosuppression
• Goals - expectations for pain relief, function and activity level

Examination. Look for the signs of an arthritic hip and for anything else that could be causing the pain:

• Gait - antalgic, Trendelenburg (abductor weakness), leg length discrepancy
• Range of motion - flexion, extension, abduction, adduction, internal and external rotation; internal rotation is lost first in OA
• Leg length - true versus apparent discrepancy (ASIS to medial malleolus)
• Neurovascular - femoral and dorsalis pedis pulses, sensation, motor function
• Associated pathology - spine (flexion deformity), knee (referred pain pattern)

Scoring severity. The Oxford Hip Score runs from 0 to 48, and a score under 30 indicates severe impairment. The other patient-reported measures are WOMAC (Western Ontario and McMaster Universities Arthritis Index), HOOS (Hip disability and Osteoarthritis Outcome Score) and the SF-36 quality-of-life measure.

Is it the hip? Before attributing pain to arthritis and offering THA, confirm that the pain is genuinely intra-articular and exclude the mimics. Examiners probe this because operating on the wrong source of pain is a classic cause of a dissatisfied "failed" THA.

View larger

Plain radiographs are essential. Two views:

• Standing AP pelvis, weight-bearing, with both hips visible
• Lateral hip, cross-table or frog-leg

They show the joint space narrowing, osteophytes, sclerosis and cysts (geodes) of osteoarthritis, and allow the hip centre, leg length and offset to be measured.

View larger

Advanced imaging is selective.

• MRI - early AVN (Stage I), soft-tissue pathology, occult fracture
• CT - DDH planning, post-traumatic deformity, bone stock assessment
• Nuclear medicine - bone scan to differentiate infection from loosening, rarely used before a primary operation

Blood tests. Look for what would delay or complicate the operation:

• FBC - anaemia, which may need preoperative iron or EPO
• UEC - renal function for NSAID use and perioperative hydration
• HbA1c - if diabetic (targets under Patient Selection)
• ESR/CRP - a raised value suggests infection and is investigated before elective THA
• Coagulation studies - if anticoagulated

Special investigations are ordered by indication:

• ECG - all patients over 50 or with a cardiac history
• Echocardiogram - cardiac symptoms or a murmur
• Pulmonary function tests - severe COPD
• Urinalysis - to rule out UTI before elective surgery

Why template. Templating is essential for:

1. Component size prediction, which reduces operative time and inventory needs
2. Leg length restoration planning
3. Offset restoration (the abductor moment arm)
4. Identifying anatomical challenges (DDH, previous surgery, deformity)

The AP pelvis. Taken standing and weight-bearing, with both hips visible, the coccyx centred and the pelvis level (obturator foramina symmetric). It carries a magnification marker, a ball bearing of known size (typically 25mm or 30mm) at the level of the greater trochanter, and is used to template acetabular component size and position.

The lateral hip. Cross-table or frog-leg lateral. It shows femoral offset and canal shape, identifies deformity (previous fracture, Paget's), and templates femoral component size and the neck-cut level.

The steps. Digital templating proceeds in order:

Special situations need their own plan:

• DDH - high hip centre, small canal, increased anteversion; may need structural graft and specialised implants
• AVN in a young patient - consider resurfacing versus THA, and template for both
• Previous surgery - retained hardware and altered anatomy; plan the hardware-removal approach
• Leg length discrepancy - a preoperative LLD may be longstanding and the patient adapted to it; discuss postoperative expectations

View larger

View larger

View larger

View larger

Before THA in a younger patient, consider the alternatives:

Hip resurfacing. Once popular in young males, now declining in use. Metal-on-metal bearings raise concerns (pseudotumour, metallosis, ARMD), and AOANJRR data show a higher revision rate than THA, especially in women. It requires a large femoral head (over 50mm) and good bone quality, and is contraindicated by renal impairment, metal allergy, osteoporosis and cysts. It is still considered in the young male athlete with a very large femoral head and strong bone who has been counselled about the risks.

View larger

View larger

View larger

These are the complications a patient must understand before consenting to THA.

View larger

View larger

Recovery follows a staged protocol from the day of surgery to the 12-month review.

Hip precautions depend on the approach:

• Posterior - no flexion over 90°, no adduction past midline, no internal rotation (6-12 weeks)
• Anterior - no extension, external rotation or adduction (6 weeks)
• Lateral - minimal restrictions; avoid extreme abduction initially

Pain. 90-95% of patients report significant pain improvement, and most are pain-free or have minimal pain at rest and with activity; night pain typically resolves completely. Groin pain may persist in 5-10%, unexplained, and may come from the spine or soft tissues.

Function. Walking distance increases dramatically and is unlimited in most patients. Stair climbing normalises, and ADLs (dressing, bathing, tying shoes) become significantly easier. 80-90% return to their previous level of work.

Satisfaction. 85-90% are "very satisfied" with the outcome, 5-10% "satisfied with reservations" (ongoing pain, stiffness, LLD), and fewer than 5% "dissatisfied" (persistent pain, complications, unmet expectations).

Implant survival. AOANJRR data:

• 5 years - 97% survival
• 10 years - 95% survival
• 15 years - 93-95% survival (modern implants)
• 25 years - 85-90% survival (projected)

What changes the result. These factors affect the outcome, each with its mitigation:

Long-term surveillance. Review clinically every year for the first 5 years, then as needed, with X-rays at 1 year and then every 2-3 years. Watch for pain (loosening, infection), wear and osteolysis. The AOANJRR tracks THA outcomes to build the long-term evidence.

Global epidemiology. Osteoarthritis is the commonest indication for THA worldwide. The GBD 2021 study estimated 595 million people had osteoarthritis globally in 2020 (7.6% of the population), a 132% rise in cases since 1990, with hip OA cases projected to increase 78.6% by 2050; high BMI accounts for roughly 20% of the burden. This rising, ageing, increasingly obese population is driving worldwide growth in THA demand.

Major guidelines, side by side. Recommendations are broadly concordant: a structured trial of non-operative care first, then THA for symptomatic end-stage disease refractory to that care. The threshold and emphasis differ.

Registry evidence. National joint registries are the highest-volume source of revision data and consistently agree on the major messages below.

Global practice variation. Fixation philosophy differs by region: cemented and hybrid THA predominate in Scandinavia, the UK and other registry-driven systems (registry-driven), whereas cementless fixation predominates in the USA and much of Asia. In high-resource settings the debate is bearing surface and approach; in limited-resource settings access, implant availability and cost dominate, and conventional rather than cross-linked polyethylene or cemented implants may be used for economic reasons. Across all systems the indication itself - disabling symptomatic end-stage hip disease that has failed appropriate conservative care - is universal.