Enhanced Recovery After Surgery (ERAS)

Part of The Joint Replacement Guide — Phase 5: Recovery and Rehabilitation · Article 30 of 44 · Hip & Knee

Key Points

  • Enhanced Recovery After Surgery, or ERAS, is a coordinated pathway covering preparation, the operation, recovery and discharge.
  • It combines several evidence-based measures rather than relying on one particular anaesthetic, surgical approach or rehabilitation technique.
  • The clearest demonstrated benefit after hip and knee replacement is a shorter hospital stay without a consistent increase in readmission.
  • Some studies report fewer complications, but this finding is less consistent and cannot always be attributed to ERAS alone.
  • ERAS encourages early eating, drinking and movement when clinically safe; it does not mean rushing patients home or applying the same timetable to everyone.
  • Your participation is valuable, but delays caused by pain, dizziness or medical problems are not personal failures.

What Is ERAS?

Enhanced Recovery After Surgery is not a single treatment. It is a structured way of organising care so that the different parts of the surgical pathway support one another.

Instead of treating preoperative preparation, anaesthesia, pain relief, mobilisation and discharge as unrelated stages, ERAS brings them together into one multidisciplinary programme.

The pathway usually involves:

  • surgeons;
  • anaesthetists;
  • nurses;
  • physiotherapists;
  • occupational therapists;
  • pharmacists;
  • pre-assessment staff; and
  • the patient and their support network.

The aim is to reduce the physical stress of surgery, maintain normal function where possible and help patients achieve a safe recovery without unnecessary delays.

What ERAS Is Not

ERAS does not mean:

  • sending every patient home on the day of surgery;
  • forcing someone to walk before it is safe;
  • withholding appropriate pain relief;
  • using one compulsory type of anaesthetic;
  • performing a smaller or less complete operation;
  • replacing clinical judgement with a fixed protocol; or
  • expecting every patient to recover at the same speed.

A good enhanced-recovery pathway remains individualised. Elements may need to be changed for patients with frailty, significant medical conditions, complex surgery or limited support at home.

Before Surgery

An ERAS pathway begins before admission.

Common elements include:

  • clear information about what to expect;
  • shared goal-setting and discharge planning;
  • review and optimisation of relevant health conditions;
  • treatment of anaemia where appropriate;
  • support with smoking cessation and alcohol reduction;
  • diabetes management;
  • nutrition assessment where indicated;
  • instructions about medicines and fasting;
  • planning blood-clot prevention; and
  • preparing the home and support arrangements.

Formal prehabilitation exercise may be offered by some hospitals. It can improve confidence and early strength in selected patients, but it is not an essential component of every ERAS pathway. Evidence does not show that preoperative physiotherapy in isolation reliably shortens hospital stay after routine joint replacement.[1]

Fasting and Nutrition

Traditional surgical care often involved fasting from midnight and delaying food after surgery. Modern pathways aim to avoid fasting for longer than necessary.

Your hospital will provide exact instructions about:

  • when to stop eating;
  • which fluids may be taken;
  • which medicines to take; and
  • whether any carbohydrate drink is appropriate.

These instructions must be followed even if they differ from general ERAS information found elsewhere.

After surgery, patients are usually encouraged to drink and return to normal food as soon as they feel able and it is clinically safe. Intravenous fluids are used where necessary but are generally reduced once adequate drinking resumes.[1]

Anaesthesia

ERAS is sometimes closely associated with spinal anaesthesia, and many hospitals have developed pathways in which a spinal anaesthetic is the usual technique for hip or knee replacement.

However, ERAS does not require a spinal anaesthetic in every patient. The ERAS Society guidance states that modern general anaesthesia and neuraxial techniques such as spinal anaesthesia can both form part of an enhanced-recovery pathway.[1]

The most appropriate option depends on:

  • the operation;
  • your health;
  • medication and bleeding risks;
  • previous spinal surgery or anatomical considerations;
  • local practice;
  • your preferences; and
  • the anaesthetist’s assessment.

The anaesthetic plan should therefore be discussed with your anaesthetist rather than presented as a compulsory feature of ERAS.

Pain Relief

Effective pain relief is central to enhanced recovery because excessive pain can prevent breathing exercises, sleep, eating and movement.

ERAS pathways generally use multimodal analgesia—combining treatments that work in different ways. These may include:

  • paracetamol;
  • anti-inflammatory medication where suitable;
  • local anaesthetic infiltration;
  • selected nerve blocks;
  • ice or elevation; and
  • opioid medication when needed.

The aim is to provide adequate pain relief while reducing avoidable opioid side effects such as nausea, drowsiness, constipation and confusion.

Opioid-sparing does not mean opioid-free at all costs. Stronger medication remains appropriate when required, particularly during the early period after knee replacement.

During the Operation

Elements commonly incorporated into an ERAS pathway include:

  • timely preventive antibiotics;
  • tranexamic acid to reduce blood loss where appropriate;
  • maintaining normal body temperature;
  • careful fluid management;
  • evidence-based blood-clot prevention;
  • minimising unnecessary tissue damage; and
  • avoiding routine drains or tubes where they provide no clear benefit.

ERAS does not prescribe one surgical approach, implant, fixation method or robotic technology. The operation should still be selected and performed according to the patient’s needs and the surgeon’s established technique.

Catheters, Drains and Drips

Traditional pathways sometimes used urinary catheters, surgical drains and prolonged intravenous fluids routinely.

Enhanced-recovery guidance recommends avoiding unnecessary tubes and removing them early where they are required. Routine urinary catheterisation and routine surgical drains are not recommended for uncomplicated hip and knee replacement.[1]

This does not mean they are never appropriate. A catheter, drain or continued intravenous infusion may be needed because of the operation, urinary retention, blood pressure, fluid balance or another clinical concern.

Early Mobilisation

Patients are encouraged to sit, stand and begin walking as early as they are safely able.

For many people, this occurs on the day of surgery. For others, mobilisation begins the following morning because:

  • surgery finishes later;
  • spinal anaesthesia has not fully worn off;
  • pain or nausea needs further treatment;
  • blood pressure is low;
  • muscle control has not returned; or
  • medical supervision is required.

Early mobilisation helps patients regain function and is associated with a shorter hospital stay.[1] It also limits the adverse effects of prolonged bed rest.

Movement works alongside—not instead of—blood-thinning medication and other clot-prevention measures.

Criteria-Based Discharge

ERAS aims for discharge when agreed safety and functional criteria have been met, rather than after an arbitrary number of nights in hospital.

Before going home, the team will usually need to be satisfied that you:

  • are medically stable;
  • have manageable pain and nausea;
  • can eat and drink;
  • can pass urine where required;
  • can mobilise safely with the recommended aid;
  • can manage any necessary steps or stairs;
  • understand your medicines and wound care;
  • have an appropriate blood-clot prevention plan; and
  • have adequate support and follow-up arrangements.

Some patients meet these criteria on the day of surgery. Many go home the following day or after another short stay. Others appropriately remain longer.

A shorter stay is beneficial only when discharge is safe and properly supported.

What Does the Evidence Show?

The most consistent finding is that ERAS pathways reduce average hospital length of stay after primary hip and knee replacement.[2]

The evidence concerning complications is less straightforward. Some systematic reviews and randomised-trial analyses report fewer postoperative complications or transfusions.[3] Other reviews find little or no effect on overall perioperative morbidity.[2]

This variation occurs partly because:

  • ERAS programmes contain different combinations of interventions;
  • conventional care has itself adopted many ERAS principles;
  • healthier patients may be selected for the fastest pathways;
  • studies define complications differently; and
  • improvements occurring over time may reflect several changes in care.

It is therefore reasonable to say that ERAS supports efficient recovery without an apparent increase in readmission. It is too strong to claim that ERAS alone has definitively prevented every category of complication, including blood clots or chest infections.

Your Role in ERAS

ERAS works best as a partnership.

Your contribution may include:

  • providing accurate information about your health and medicines;
  • following fasting and medication instructions;
  • preparing your home and support arrangements;
  • participating in appropriate preparation or exercise;
  • reporting pain, nausea or dizziness honestly;
  • taking medicines as agreed;
  • attempting supervised mobilisation;
  • practising the recommended exercises; and
  • asking questions when anything is unclear.

Participation does not mean pushing through severe pain, hiding symptoms or attempting to walk without help.

If medical issues delay your progress, the pathway should adapt to you. ERAS is intended to support recovery, not to judge patients against a rigid schedule.

The Role of Family and Support

Family members or friends can support enhanced recovery by:

  • helping prepare the home;
  • arranging transport;
  • listening to medication and discharge instructions;
  • encouraging safe activity;
  • helping with food and practical tasks; and
  • watching for the warning signs explained by the clinical team.

They should not pressure you to achieve a particular milestone or change your exercises or medication without professional advice.

Why Pathways Differ Between Hospitals

Hospitals may use different:

  • fasting instructions;
  • anaesthetic techniques;
  • pain-relief combinations;
  • mobilisation schedules;
  • blood-clot prevention;
  • physiotherapy arrangements; and
  • discharge pathways.

A hospital can follow enhanced-recovery principles without using an identical protocol to another centre.

The quality of ERAS depends not only on which elements appear in a written pathway, but also on reliable delivery, communication, staff training and ongoing review of outcomes.

In More Depth

The principles behind ERAS were pioneered by Danish surgeon Professor Henrik Kehlet and colleagues during the 1990s. Their work challenged traditional practices such as prolonged fasting, extended bed rest and delayed return to normal activity.[4]

Formal ERAS programmes were initially developed particularly in colorectal surgery before spreading to other specialties. Hip- and knee-specific recommendations now cover the whole perioperative pathway, including education, anaesthesia, pain relief, blood management, nutrition, mobilisation and discharge.[1]

ERAS should be understood as coordinated evidence-based care rather than a race towards discharge. Its success is measured by safe recovery, function and patient experience—not simply by the number of hours spent in hospital.

This article provides general information and does not replace individual clinical advice. Your hospital’s medication, fasting, mobilisation and discharge instructions take priority over this general description.

References

  1. Wainwright TW, Gill M, McDonald DA, et al. Consensus statement for perioperative care in total hip replacement and total knee replacement surgery: Enhanced Recovery After Surgery Society recommendations. Acta Orthop. 2020;91(1):3–19. doi: 10.1080/17453674.2019.1683790.
  2. Morrell AT, Layon DR, Scott MJ, Kates SL, Golladay GJ, Patel NK. Enhanced recovery after primary total hip and knee arthroplasty: a systematic review. J Bone Joint Surg Am. 2021;103(20):1938–1947. doi: 10.2106/JBJS.20.02169.
  3. Zhou W, Chu S, Zhou Y, Huang Y. Enhanced recovery after surgery for hip and knee arthroplasty: a systematic review and meta-analysis of randomized controlled trials. Geriatr Nurs. 2024;59:237–245. doi: 10.1016/j.gerinurse.2024.08.002.
  4. Kehlet H. Multimodal approach to control postoperative pathophysiology and rehabilitation. Br J Anaesth. 1997;78(5):606–617. doi: 10.1093/bja/78.5.606.
  5. ERAS Society. Orthopaedic enhanced-recovery guidelines and resources. ERAS Society orthopaedics.

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