The three criteria that decide candidacy

Your surgeon is looking for three things to converge before recommending hip replacement — and all three need to be present, not just one.

A confirmed structural diagnosis. The first requirement is a condition causing genuine joint damage. Osteoarthritis accounts for roughly 90% of hip replacements, making it by far the most common indication. Rheumatoid arthritis, post-traumatic arthritis (damage following a fracture or injury), avascular necrosis, and hip fractures are also accepted indications when they reach a comparable level of joint destruction.

Measurable functional loss. A diagnosis alone is not enough. Surgeons look for pain that persists at rest or disrupts sleep, alongside difficulties with everyday tasks — walking any meaningful distance, climbing stairs, getting in and out of a chair, or putting on shoes and socks. These functional markers establish that the condition is genuinely limiting quality of life, not merely visible on a scan.

Documented failure of conservative treatment. NHS clinical policy is clear that patients should not be considered for joint replacement until non-surgical options have been tried and have failed to provide adequate, sustained relief. This typically means NSAIDs, physiotherapy, walking aids, and corticosteroid injections have all been pursued without sufficient benefit.

X-ray imaging sits alongside these three criteria rather than above them. Evidence of bone-on-bone wear or advanced arthritic change is a required part of the assessment — it confirms the structural picture and supports the clinical decision — but imaging alone does not determine candidacy. A scan showing significant degeneration in a patient whose symptoms are well controlled, for example, would not automatically lead to surgery. The imaging must correlate with what the patient is actually experiencing.

Age and weight in hip arthroplasty decisions

Two questions come up repeatedly among patients weighing a hip replacement decision: am I too young? and am I too heavy? The short answer to both is that no fixed threshold exists — but the reasoning behind each is worth understanding.

Most people who have a hip replaced are aged between 60 and 80, largely because osteoarthritis is an age-related condition. Younger adults are not excluded, however. Modern implants achieve around 58% survival at 25 years, and with optimised patient selection and technique, longevity beyond 30 years is achievable. The honest caveat for younger patients is that a longer life ahead means a greater chance of eventually needing a revision procedure — so surgeons weigh timing carefully against quality-of-life impact rather than applying a blanket age rule.

On weight, higher BMI is treated as a relative risk factor, not an automatic barrier. It is associated with wound-healing difficulties, increased DVT risk, and earlier prosthetic loosening. Depending on the degree of risk, this may prompt a pre-surgical optimisation programme — weight management, cardiovascular review, or smoking cessation — before a date is set. NHS guidance uses BMI thresholds as risk guides; no single number is universally confirmed as an absolute cut-off, and clinical context always applies.

In both cases, the central question returns to functional limitation: how severely is the hip affecting daily life, and do the benefits of surgery outweigh the individual risks?

Conditions that can delay or rule out surgery

Not every contraindication means a permanent refusal. Surgeons draw a firm line between one absolute barrier and a wider set of relative ones that typically call for preparation rather than exclusion.

The single absolute contraindication is an active local or systemic infection anywhere in the body. Implanting a prosthesis while infection is present creates an unacceptable risk of seeding the new joint, so surgery cannot proceed until it is fully resolved.

Relative contraindications are conditions that raise operative risk to a level where delay or optimisation is warranted:

• Severe uncontrolled cardiovascular or pulmonary disease — heart or lung function must be stable enough to tolerate anaesthesia and the demands of early rehabilitation.
• Severe osteoporosis — if bone density is insufficient to anchor an implant reliably, surgery may be deferred until bone health is addressed.
• Morbid obesity — this is listed as a relative contraindication for comparable reasons to those already outlined; the degree of risk guides whether optimisation is needed first.
• Active nicotine use — smoking is linked to higher infection rates and an increased likelihood of requiring revision surgery.
• Cognitive or neuromuscular impairment — where a patient is unlikely to complete the post-operative rehabilitation programme, dislocation risk rises and outcomes are less predictable.

For most of these, the clinical response is a pre-operative optimisation plan — smoking cessation support, cardiac review, or weight-management input — not a closed door. Whether any of these factors apply, and how much weight they carry in an individual case, is assessed during the orthopaedic consultation.

What the candidacy assessment actually involves

The assessment process unfolds in two stages, and understanding what happens at each makes preparation straightforward.

Stage one: orthopaedic consultant assessment

The first appointment covers four connected elements: a structured review of symptoms and how pain affects daily life; a physical examination of hip range of motion and strength; X-ray review to confirm visible joint damage; and a frank discussion of any non-surgical options that remain realistic given the current picture. Where objective baseline data is useful, gait and biomechanical assessment using MAI Motion® can supplement clinical examination, capturing how the hip is functioning before any intervention.

Stage two: pre-operative fitness clinic

If surgery is the agreed direction, a nurse-led pre-operative assessment confirms that the patient is fit to proceed. This typically covers an ECG, blood and urine tests, MRSA screening, blood pressure measurement, and an anaesthesia review. An occupational therapist may also assess the home environment as part of discharge planning.

Expectation-setting as a clinical step

The first consultation is equally where patient expectations are examined directly — what activities the patient most wants to recover, and what residual limitations surgery cannot resolve. A shared, realistic understanding of likely outcomes is treated as part of determining suitability, not as a formality at the end of the appointment. Patients who have that clarity early are better placed to make a genuinely informed decision.

Hip Replacement Lincolnshire assessments are consultant-led and available without a GP referral, with clinics in Sleaford and Grantham.

How surgical approach factors into your suitability picture

Surgical approach is not a detail finalised after candidacy is confirmed — for an experienced hip surgeon, it is part of the suitability conversation from the outset, because different approaches carry meaningfully different risk profiles for different patient groups.

The standard posterior approach is technically versatile and remains the most widely used method. Its relative limitation for certain patient profiles is a higher dislocation rate than muscle-sparing alternatives: data indicate that younger age, female sex, and low BMI each independently amplify that risk after traditional posterior total hip arthroplasty.

The anterior (DAA) approach reaches the joint from the front, preserving the posterior soft tissue. Trade-offs include lateral femoral cutaneous nerve symptoms in a proportion of patients, more restricted access to the femoral canal in some anatomies, and theatre equipment requirements that are not universally available.

SPAIRE — Saves Piriformis And Obturator Internus with Repair of Obturator Externus — is a muscle-sparing posterior variant that keeps the posterior tendon complex intact rather than dividing it. The intended benefit is a reduced post-operative dislocation risk and a shorter period of movement restriction. SuperPATH and other mini-posterior variants pursue a comparable soft-tissue preservation aim but differ in femoral canal preparation technique and surgical visualisation, which influences which patients are suitable candidates for each.

Because approach choice interacts with anatomy, comorbidities, and implant requirements, these considerations belong inside the candidacy assessment rather than after it. Prof Paul Lee, whose clinical work includes the SPAIRE technique alongside the full range of alternatives, incorporates approach evaluation as a standard element of the first consultation.

Getting a suitability assessment

Deciding whether hip replacement is the right step requires weighing diagnosis, symptom load, treatment history, and overall fitness together — a combination that no online checklist or self-assessment tool can reliably evaluate.

Hip Replacement Lincolnshire accepts patients without a GP referral, with consultant assessment available at Sleaford (NG34) and Grantham (NG31). The first appointment reaches a clear recommendation in both directions: for patients who meet the surgical threshold, the pathway forward is laid out; for those who do not yet qualify, the assessment maps the conservative steps that remain and identifies the point at which surgery becomes appropriate. That second outcome is clinically as useful as the first — it replaces open-ended uncertainty with a structured plan.

Book an assessment at hipreplacementlincolnshire.co.uk.