Preoperative Optimization & Risk Stratification for Arthroplasty
A binary sign-off - "fit / not fit for anaesthesia." It is passive, treats risk as fixed, and misses the opportunity to actually lower the patient's risk before an elective operation.
Actively identify and improve modifiable risk factors (glycaemia, nutrition, anaemia, smoking, weight, Staph carriage) before surgery. Because arthroplasty is elective, surgery can be deferred until the patient is in the best achievable state - measurably reducing complications.
Overview
Hip and knee arthroplasty are highly successful but elective procedures, so the threshold for accepting preventable risk is low. Many of the strongest predictors of complications - particularly prosthetic joint infection (PJI) - are modifiable. Pre-operative optimization systematically identifies and improves these factors, shifting care from a one-off "clearance" sign-off to an active risk-reduction programme.
The case for optimization is strongest for PJI, the most feared complication, which is devastating and costly and whose risk is concentrated in patients with controllable comorbidities. The same factors also drive wound complications, transfusion, medical complications, readmission and mortality. The surgeon's role is to screen, to set evidence-based targets, to coordinate optimization with primary care and relevant specialists, and - crucially - to be willing to delay elective surgery until modifiable risk is improved.
The Modifiable Risk Factors
Obesity, Diabetes & Nutrition
- Obesity: A high BMI is associated with more wound and infection complications and technical difficulty. Where feasible, supported weight optimization before surgery is reasonable; very high BMI thresholds for proceeding remain debated and should be individualised rather than applied as rigid cut-offs.
- Diabetes / glycaemic control: Poor glycaemic control (elevated HbA1c and perioperative hyperglycaemia) is consistently linked to increased PJI. Aim to improve glycaemic control before elective surgery and to control perioperative glucose; fructosamine may add information when HbA1c is unreliable.
- Malnutrition / hypoalbuminaemia: Serum albumin less than 3.5 g/dL is the classic marker of malnutrition and independently predicts infection and complications. Screen and correct nutrition; malnutrition can coexist with obesity.
A widely-cited synthesis proposes the following thresholds to reach before elective arthroplasty, deferring surgery until they are met:
- BMI under 40 kg/m²
- Serum albumin at least 3.5 g/dL (nutrition)
- HbA1c at or below 7.5% (with good perioperative glucose control)
- Haemoglobin above 12.0 g/dL (women) / 13.0 g/dL (men)
- Smoking ceased, and opioid use reduced by at least 50%, by ~4 weeks before surgery
- Staph aureus carriers decolonised; active infection (dental/urinary/skin) treated
These are pragmatic targets, not absolute bars — individualise (especially BMI) within a shared decision.
Specific Optimization Protocols & Pitfalls
These are the high-yield, frequently-tested specifics that turn the general principles above into a defensible viva answer.
Perioperative antirheumatic medication
The patient with inflammatory arthritis (rheumatoid arthritis, spondyloarthritis, SLE) is a classic viva: how do you manage their immunosuppression around a hip or knee replacement? The framework is the ACR/AAHKS guideline (2017, updated 2022), and the principle is to balance disease flare against infection/wound risk.
- Perioperative action
- CONTINUE through surgery
- Detail
- Continuing does not increase infection/wound complications and avoids a disease flare
- Perioperative action
- WITHHOLD
- Detail
- Schedule surgery at the END of the dosing cycle (when the next dose would be due); resume ~14 days post-op once the wound is healing and there is no infection
- Perioperative action
- WITHHOLD
- Detail
- Stop before surgery (2017 guidance: ≥7 days prior)
- Perioperative action
- CONTINUE usual daily dose
- Detail
- Give the current daily dose rather than supraphysiologic 'stress-dose' steroids
- Perioperative action
- Depends on disease severity
- Detail
- CONTINUE in severe/active SLE; withhold ~1 week pre-op in non-severe SLE
Do NOT routinely screen urine or treat asymptomatic bacteriuria (ASB) before elective arthroplasty. ASB is associated with a higher PJI rate (meta-analysis OR ~3.6), but the urinary organism rarely matches the eventual PJI organism, and preoperative antibiotics for ASB do not reduce PJI risk (OR ~1.0) — so treating it adds antibiotic resistance without benefit. Treat only a symptomatic urinary tract infection; routine urinary screening before elective TJA is not recommended.
- Anaemia pathway: investigate with iron studies (ferritin, transferrin saturation); treat iron deficiency with oral iron if there is time, or IV iron when surgery is near or oral iron is not tolerated. Do not transfuse a stable, asymptomatic patient simply to "clear" them — allogeneic transfusion is itself associated with infection and is not a preoperative optimization tool.
- Staph decolonisation protocol: screen carriers (nasal swab) and decolonise with intranasal mupirocin (typically 5 days) plus chlorhexidine body washes in the days before surgery — cheap and high-yield for reducing surgical-site infection / PJI.
A distinct preoperative task (separate from post-op VTE prophylaxis) is safely stopping chronic anticoagulants/antiplatelets and deciding who needs bridging:
- Warfarin: stop about 5 days before surgery and check the INR on the day (aim near normal, ~under 1.5). Bridge with LMWH only for high thrombotic risk (a mechanical mitral valve, recent VTE within ~3 months, high-risk AF) — routine bridging of low-risk AF adds bleeding without benefit.
- DOACs: stop ~2-3 days pre-op (the interval depends on the agent, the bleeding risk and renal function — e.g. dabigatran needs longer with a low creatinine clearance); no bridging is needed because of their short half-life.
- Antiplatelets: continue or stop aspirin according to its indication; clopidogrel/P2Y12 inhibitors are usually held ~5-7 days.
- The coronary-stent trap: a patient on dual antiplatelet therapy after a drug-eluting stent should generally have elective surgery deferred (commonly ~6 months) and DAPT must not be stopped prematurely — early cessation risks catastrophic stent thrombosis; coordinate with cardiology.
Always weigh the thrombotic risk of stopping against the bleeding/transfusion (and thus infection) risk of continuing, and document the plan.
Risk Stratification & Pathway
Optimization sits within a structured elective pathway:
- Screen at listing: history and examination for comorbidities, plus targeted investigations (glycaemic markers, albumin/nutrition screen, full blood count for anaemia, and Staph screening per local protocol).
- Stratify risk: combine comorbidity burden with the modifiable-factor profile to estimate complication and PJI risk; validated risk calculators can support shared decision-making.
- Optimise: set targets and refer/coordinate (primary care, endocrinology, dietetics, anaemia/iron service, smoking cessation, pain service) and defer elective surgery until improved where the risk-benefit balance favours waiting.
- Consent: document the individualised risk and the optimization undertaken.
The single most important principle is that this is elective surgery: time is on your side. A short delay to correct anaemia, improve glycaemic control, achieve smoking cessation, decolonise Staph carriage and address nutrition can meaningfully reduce the risk of a catastrophic complication.
"Validated risk calculators" should be named in a viva. The examinable tools:
- ASA physical status (I-V) — the simplest global descriptor of perioperative fitness.
- ACS-NSQIP Surgical Risk Calculator — a procedure-specific, multi-variable estimate of complication/mortality risk for shared decision-making.
- Comorbidity indices — the Charlson (and Elixhauser) comorbidity index for cumulative comorbidity burden.
- Cardiac risk — the Revised Cardiac Risk Index (RCRI / Lee index) plus functional capacity: a patient who can achieve roughly 4 METs (e.g. climb two flights of stairs) without symptoms rarely needs further cardiac testing before intermediate-risk surgery.
Beyond comorbidity counts, frailty independently predicts complications and mortality more than chronological age: assess it with the modified frailty index (mFI-5), gait speed or grip strength, and use a positive screen to trigger prehabilitation (exercise, nutrition, anaemia and glycaemic optimisation) rather than to deny surgery — frailty is partly modifiable and is the bridge between risk stratification and the optimisation pathway.
SMOKED INModifiable Risk Factors to Optimise
Hook:A patient who SMOKED IN their risk factors is optimised by reversing each one.
Guidelines, Registries & Global Practice
Global Consensus Direction
Internationally, preoperative care for arthroplasty has shifted from anaesthetic "clearance" toward structured optimization of modifiable risk factors, reflected in society guidance and enhanced-recovery pathways across North America, the UK/Europe and Australasia. The consistent themes are glycaemic control, nutrition, anaemia management (patient blood management), smoking cessation, weight optimization, and Staph decolonisation, all directed at reducing PJI and complications.
Side-by-Side Synthesis
- Optimization goal
- Improve glycaemic control pre-op
- Why it matters
- Hyperglycaemia raises PJI risk
- Optimization goal
- Correct albumin less than 3.5 g/dL
- Why it matters
- Malnutrition predicts infection/complications
- Optimization goal
- Treat (iron) before surgery
- Why it matters
- Reduces transfusion and complications
- Optimization goal
- Cessation before surgery
- Why it matters
- Fewer wound/infection complications
- Optimization goal
- Screen + decolonise
- Why it matters
- Cheap, high-yield SSI/PJI reduction
- Optimization goal
- Wean pre-op
- Why it matters
- Better pain, function, satisfaction
Practice Variation
Resource-rich systems run dedicated optimization or "joint school" clinics with multidisciplinary input; lower-resource settings achieve much of the benefit with simple, low-cost measures - smoking cessation advice, glycaemic and nutritional screening, treatment of active infection, and Staph decolonisation. The common, universally applicable lever is that arthroplasty is elective: there is time to optimise.
Evidence Base
All five citations were verified against PubMed. The conceptual anchor is the MacMahon narrative review (69 studies), which both reframes care as optimization and gives the concrete, exam-quotable thresholds (BMI under 40, albumin at least 3.5, HbA1c at or below 7.5%, Hb over 12/13, smoking cessation + 50% opioid reduction by 4 weeks). The Johns systematic review supplies the hard outcome justifying the effort — protocolised optimization roughly quartered surgical-site infection (0.56% vs 2.60%, RR 0.21) and cut length of stay, cost and readmissions. Chan ties it to the purpose: preventing PJI. The ACR/AAHKS guideline gives the antirheumatic-drug specifics (continue traditional DMARDs, withhold biologics around the dosing cycle), and the Sousa meta-analysis underpins the asymptomatic-bacteriuria rule (don't screen/treat — antibiotics don't lower PJI). All are review/guideline/observational (no RCT of a whole optimization pathway exists), so the honest framing is "strongly supported by consistent observational and consensus evidence," and the targets are pragmatic, individualised goals — not absolute bars.
Preoperative Patient Optimization in Total Joint Arthroplasty—The Paradigm Shift from Preoperative Clearance: A Narrative Review
- Narrative review reframing preoperative care as optimization of modifiable risk factors rather than a binary 'clearance'
- Focuses on seven modifiable factors: obesity, malnutrition, hypoalbuminaemia, diabetes, anaemia, smoking, and opioid use
- Each factor is independently associated with worse outcomes after total joint arthroplasty
- Develops recommendations for optimising each before elective surgery
Preoperative Risk Factor Screening Protocols in Total Joint Arthroplasty: A Systematic Review
- Systematic review of 8 cohort studies (9,915 patients) of preoperative optimization protocols targeting modifiable risk factors in lower-extremity total joint arthroplasty
- Protocols target factors such as glycaemic control, nutrition, obesity, smoking and Staph carriage
- Protocol implementation was associated with a markedly lower surgical site infection rate (0.56% vs 2.60%; RR 0.21, 95% CI 0.12-0.37) plus shorter length of stay, lower cost and fewer readmissions
- Supports formalised, protocolised preoperative optimization pathways over ad hoc assessment
Preoperative optimization to prevent periprosthetic joint infection in at-risk patients
- Review focused on preoperative assessment and optimization of risk factors to prevent prosthetic joint infection
- The preoperative phase is a unique opportunity to screen, diagnose and optimise modifiable comorbidities
- Addresses glycaemic control, nutrition, Staph decolonisation, and treatment of active infection
- Optimising modifiable risk is central to PJI prevention given its devastating consequences