Enhanced Recovery After Surgery (ERAS) Protocols

Preoperative phase - days to weeks before surgery

Patient education. An informed patient is less anxious and more compliant. Cover, in writing and in conversation:

• What to expect on the day of surgery
• Realistic pain goals - VAS 3-4, not 0
• The mobilisation timeline, walking on day 0
• Expected length of stay, 24-48 hours for TKA or THA
• The discharge criteria they will have to meet
• Red flags for complications
• The follow-up plan

Delivery can be by booklet, video, group class or one-to-one counselling.

Prehabilitation. A 4-6 week programme of exercise before surgery: quadriceps, hip abductor and core strengthening, with walking or cycling for cardiovascular reserve, alongside the same education and protein supplementation where it is needed. Meta-analyses show modest improvements in functional outcomes, particularly in frail and elderly patients, with a larger effect size in those whose baseline function is poor.

Optimisation before the list. Malnutrition is corrected with protein supplementation, with an albumin target of 35 g/L, and anaemia with intravenous iron where haemoglobin is under 130 g/L in men or 120 g/L in women. Smoking and alcohol stop 4-6 weeks beforehand where that is possible, and diabetes and cardiac risk are addressed before the patient reaches theatre. Bowel preparation is avoided unless there is a specific indication, since it brings dehydration and electrolyte disturbance.

Intraoperative phase

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The standard regimen for TKA or THA layers four groups of agents.

• Baseline, around the clock. Paracetamol 1g orally or intravenously before incision, then 1g QID, with celecoxib 200mg orally before incision then 200mg BD, or parecoxib 40mg IV BD if the patient is nil by mouth
• Local techniques. Local infiltration analgesia into the joint capsule and soft tissues by the surgeon, and a peripheral nerve block - the adductor canal block for TKA, which spares quadriceps strength where a femoral nerve block does not
• Adjuncts. Gabapentin 300-600mg or pregabalin 75-150mg before incision as a single dose, which reduces neuropathic pain, and dexamethasone 8mg IV, which is anti-inflammatory, anti-emetic and analgesic at once
• Opioids, rescue only. Immediate-release oxycodone as required for breakthrough pain, avoiding long-acting and extended-release preparations

Routes vary - intravenous, oral or topical - and the regional techniques, spinal and epidural anaesthesia, belong to the same opioid-sparing strategy.

Tranexamic acid. Intravenously, 1g before incision repeated at 3 hours, or 2g as a single dose; topically, 2-3g in 100mL of saline injected into the joint before closure with any drain clamped for 2 hours. Intravenous and topical together may have additive benefit. A Cochrane review shows blood loss reduced by 30-50% and transfusion rate by 40-50% in TKA and THA, with no increased VTE risk; active thromboembolic disease is a contraindication, and a seizure history a relative one.

Goal-directed fluid therapy. The target is euvolaemia, avoiding hypovolaemia with its organ hypoperfusion and hypervolaemia with its tissue oedema and delayed recovery. Heart rate, blood pressure and urine output are the clinical guide; pulse pressure and stroke volume variation add precision where an arterial line is in place, and oesophageal Doppler cardiac output monitoring is rarely used in routine arthroplasty. Aim for a mean arterial pressure over 65 mmHg, urine output over 0.5 mL/kg/h and lactate under 2 mmol/L, using balanced crystalloids - Hartmann's or Plasma-Lyte - which cause less hyperchloraemic acidosis than 0.9% saline.

Postoperative phase

The mobilisation timetable after TKA or THA. On the day of surgery the patient sits out of bed at 2 hours and walks at 4 hours with physiotherapy assistance. On day 1 they walk independently with aids, practise stairs and aim for 30m or more; on day 2 they meet the discharge criteria and are safe for home, with opioids weaned and thromboprophylaxis and discharge planning continuing throughout.

What actually stops a patient mobilising. Inadequate analgesia is the commonest barrier, followed by excessive sedation from opioids, orthostatic hypotension from hypovolaemia or from excessive fluids, fear and anxiety, and a shortage of physiotherapy. Each has its answer: optimise the multimodal regimen and minimise opioids, keep the patient euvolaemic with goal-directed fluids, educate before the operation, and staff a dedicated ERAS physiotherapy team.

Thromboprophylaxis. Chemical prophylaxis starts 6-12 hours after surgery and runs alongside mechanical measures.

• Enoxaparin 40mg SC daily - 10-14 days after TKA, 28-35 days after THA
• Rivaroxaban 10mg orally daily, or apixaban 2.5mg BD - same start and duration
• Aspirin 100mg daily - an alternative in low-risk patients, in some protocols
• Intermittent pneumatic compression until the patient is fully mobile, with thromboembolic stockings

LMWH and DOACs are the standard pharmacological prophylaxis after arthroplasty, and guidelines recommend extended prophylaxis of 28-35 days for THA. Refer to local protocols.

Early oral nutrition. Clear fluids resume immediately in the recovery room and a normal diet on the evening of surgery if there is no nausea; nasogastric tubes are not used routinely, since they delay oral intake and add discomfort. Aim for protein intake of 1.2-1.5 g/kg/day to support wound healing, calories sufficient to prevent catabolism, and correction of any deficiency, including vitamin D and calcium for bone health.

Nausea and vomiting. The risk factors are female sex, non-smoking status, a history of PONV or motion sickness, and postoperative opioid use. Prevention is multimodal in the same way analgesia is: dexamethasone 8mg IV intraoperatively, ondansetron 4mg IV at the end of surgery, minimal opioids and adequate hydration from goal-directed fluids, with metoclopramide 10mg IV or promethazine 25mg IV/IM as rescue.

ERAS for total knee and hip arthroplasty

Arthroplasty has the most mature ERAS protocols in orthopaedics, with Level I evidence behind multiple elements.

A knee hurts more than a hip. TKA is typically more painful than THA in the first 24-48 hours, which is why multimodal analgesia is essential rather than optional here: local infiltration analgesia with ropivacaine and ketorolac, an adductor canal block, paracetamol and a COX-2 inhibitor around the clock, and opioids for breakthrough alone.

Targets after TKA. Straight leg raise by 4 hours, walking with a walker by 6 hours, stairs by day 1, and discharge on day 1-2 if the criteria are met. Those criteria are walking 30m or more with a walker, managing stairs if there are stairs at home, pain controlled on oral analgesia with a VAS under 4, no wound or neurovascular complication, and adequate support at home.

THA is the easier pathway. A hip replacement is generally less painful than a knee, returns to mobilisation faster and carries a lower DVT risk. The patient stands and walks by 4 hours, mobilises independently with aids by the evening of surgery, and can go home on day 1 if the criteria are met.

Hip precautions. Traditional practice restricted flexion beyond 90 degrees, adduction past the midline and internal rotation for 6-12 weeks. An ERAS pathway applies no routine precautions where the implant is stable and the soft tissues have been adequately repaired, and randomised trials show no difference in dislocation rate with or without precautions in primary THA with modern techniques.

What the pooled data show. Meta-analyses and systematic reviews report length of stay a mean 1.5-2.5 days shorter (typically 1-2 days against 3-4 days traditionally), 30-40% fewer medical and 20-30% fewer surgical complications, no increase in readmission - some studies show a reduction - and significant per-patient cost savings from the shorter stay and the avoided complications.

What the registry can and cannot say. ERAS protocols are increasingly adopted by high-volume centres, with no adverse effect on revision rates or patient-reported outcomes in AOANJRR data. The registry does not capture length of stay, so the trend towards shorter stays comes from hospital data rather than from registry reporting.

ERAS for spine surgery

Spine adopted ERAS later than arthroplasty, on a growing evidence base, and the ERAS Society published its spine surgery guidelines in 2019.

Selection and preparation. ERAS is most effective for elective one- and two-level fusions and decompressions. Prehabilitation concentrates on core strengthening, and smoking cessation is critical because of its effect on fusion rates; fasting is minimised with carbohydrate loading as in any ERAS pathway.

In theatre. Minimally invasive techniques - tubular retractors, endoscopic approaches - reduce muscle trauma. Analgesia is intravenous paracetamol with ketorolac intraoperatively and local anaesthetic infiltration of the wound and paraspinal muscles; intrathecal morphine is a consideration, but is controversial and can delay discharge. TXA 1-2g IV reduces blood loss in fusion surgery, and goal-directed fluid therapy is critical for prone positioning.

Afterwards. Mobilise on the evening of surgery after microdiscectomy and on day 1 after fusion. Bracing is minimised, since modern instrumentation is usually stable without a brace; drains are avoided, since meta-analyses show no benefit from routine drainage in spine surgery; and thromboprophylaxis combines LMWH with mechanical measures, the risk being higher than in arthroplasty because of prone positioning.

The evidence, and its limits. Systematic reviews report length of stay shorter by 1-2 days, opioid use down 30-40% with multimodal analgesia, a modest 10-20% reduction in complications, and improved patient satisfaction. The evidence is strongest for elective one- and two-level procedures; complex deformity surgery has a less robust ERAS evidence base, and neurologic complications are not reduced, with no harm from ERAS either.

ERAS for hip fracture surgery

The population is elderly and frail with multiple comorbidities, so ERAS principles are adapted to the fragility fracture context.

The first 24 hours. An orthogeriatrician is involved from admission as part of a multidisciplinary team. Dehydration is treated, electrolytes corrected and cardiac status optimised; a fascia iliaca block reduces pain and makes assessment easier; and clear fluids continue until 2 hours before surgery instead of blanket fasting. Early surgery follows NICE and national guidelines.

Anaesthesia. Spinal is a reasonable default within an ERAS bundle - short-acting agents, no airway instrumentation, and it fits day-of-surgery mobilisation - but it is not superior to general anaesthesia for hip fracture. REGAIN randomised 1,600 patients: death or inability to walk at 60 days 18.5% vs 18.0%, and delirium 20.5% vs 19.7%. Choose on patient and logistic grounds, not on a delirium claim.

The rest of the theatre bundle. Multimodal analgesia with local infiltration analgesia and paracetamol, avoiding excessive opioids; TXA to reduce transfusion need; and goal-directed fluid therapy, which matters here because many elderly patients arrive hypovolaemic.

After surgery. Walk with physiotherapy assistance on day 1, even if weight-bearing is restricted. Delirium prevention means avoiding sedatives, minimising opioids and reorienting the patient. Thromboprophylaxis with LMWH or a DOAC runs for 28-35 days, bone protection means vitamin D and calcium with consideration of a bisphosphonate through a fracture liaison service, and the ward round is daily and joint - orthopaedics, geriatrics, physiotherapy, occupational therapy and social work.

What the evidence supports. National registries such as the UK NHFD associate surgery within 36 hours and orthogeriatric co-management with lower mortality and length of stay, observationally. The HIP ATTACK randomised trial (Lancet 2020) showed that ultra-early surgery at a median of 6 hours against 24 hours did not significantly reduce 90-day mortality or major complications, so the guideline target of 36-48 hours is about avoiding harmful delay rather than racing to theatre. Early mobilisation on day 1 and orthogeriatric input remain associated with fewer complications, and the ANZHFR (Australian and New Zealand Hip Fracture Registry) shows similar trends, with surgery within 36-48 hours the standard of care and guidelines recommending multidisciplinary hip fracture units.