Outpatient / Day-care Joint Replacement — Safety & Protocols

Outpatient (same-day discharge) and day-care joint replacement — performing total hip arthroplasty (THA) or total knee arthroplasty (TKA) with discharge on the day of surgery or within 23 hours — has emerged as a safe and cost-effective alternative to traditional inpatient joint replacement for carefully selected patients. Driven by advances in multimodal analgesia, regional anaesthesia, surgical efficiency, and enhanced recovery protocols, outpatient joint replacement has grown substantially in the USA and increasingly in the UK and Europe. The key principles are appropriate patient selection, optimised perioperative pathways, robust social support, and clear criteria-based discharge rather than time-based discharge.

• Definitions: outpatient joint replacement (OJR) — discharge on the day of surgery (same-day discharge, SDD); day-care / 23-hour stay — discharge within 23 hours; short-stay — discharge within 1–2 days; these are distinct from the traditional 3–5 day inpatient admission; the term `ambulatory joint replacement` encompasses all same-day and next-day discharge pathways
• Rationale: cost reduction (reduced hospital bed utilisation — outpatient TKA costs approximately 30–50% less than inpatient); reduced hospital-acquired infection risk (nosocomial infection from prolonged inpatient stay); patient preference (many patients prefer to recover in a familiar home environment); equivalent or superior clinical outcomes in selected patients (lower VTE rates, equivalent revision rates, lower 90-day complication rates vs inpatient in registry data); earlier mobilisation and recovery when the enhanced recovery protocol is correctly applied
• Growth: in the USA, outpatient TKA and THA were removed from the Medicare `Inpatient Only` list (TKA in 2018, THA in 2020), enabling same-day discharge billing; this regulatory change accelerated adoption; by 2022, approximately 20–30% of primary TKA and THA in the USA were performed as outpatient or short-stay procedures

• The SAFE mnemonic for outpatient joint replacement selection: Social support (a responsible adult must be available at home for 24–48 hours post-discharge; patient must live within a reasonable distance of the hospital — typically <30–45 minutes — for emergency access); Age and medical status (ASA I–II preferred; ASA III acceptable if the comorbidity is well-controlled — e.g., well-controlled hypertension or diet-controlled diabetes; ASA IV is a contraindication); Functional status (must be sufficiently mobile and cognitively intact to participate in a home rehabilitation programme; BMI <40 generally); Expectations (patient must understand and agree to the outpatient pathway; patient engagement and compliance with the enhanced recovery protocol is essential)
• Absolute contraindications: ASA IV; uncontrolled cardiac disease (recent MI within 3 months, unstable angina, severe heart failure — NYHA III–IV, severe pulmonary hypertension); severe COPD (FEV1 <50%); morbid obesity (BMI >45–50 — higher anaesthetic and surgical risk; prolonged operative time); obstructive sleep apnoea requiring CPAP (if not compliant with CPAP at home — risk of nocturnal desaturation post-discharge); cognitive impairment or dementia (cannot manage home rehabilitation); living alone without support; known clotting disorder requiring inpatient anticoagulation management
• Relative contraindications: BMI 40–45; poorly controlled diabetes (HbA1c >8.5%); prior contralateral joint replacement within 3 months; chronic renal failure (eGFR <30); cirrhosis; major psychological comorbidity; complex primary or revision surgery anticipated; prior adverse anaesthetic events
• Pre-operative optimisation: HbA1c <8.5% (ideally <7.5%) for diabetics; haemoglobin optimisation (target Hb ≥120 g/L for women, ≥130 g/L for men — treat pre-operative anaemia with IV iron or erythropoietin if necessary; pre-operative anaemia is the strongest predictor of transfusion and extended hospital stay); BMI reduction if possible; smoking cessation ≥6 weeks pre-operatively; alcohol cessation ≥4 weeks; patient education programme (joint school — pre-operative group education about the pathway, expectations, analgesia, and rehabilitation); physiotherapy assessment of baseline function

• Regional anaesthesia as the cornerstone: spinal anaesthesia (intrathecal bupivacaine ± intrathecal opioid) is the preferred anaesthetic for outpatient joint replacement; spinal anaesthesia avoids the nausea, drowsiness, and prolonged recovery associated with general anaesthesia; low-dose spinal (hyperbaric bupivacaine 7.5–10 mg) allows earlier motor recovery (walk-ready within 3–4 hours of surgery) compared to standard-dose spinal (>15 mg); this `low-dose spinal` technique is essential for same-day discharge — standard-dose spinal blocks motor function for 6–8 hours, preventing discharge
• Multimodal analgesia — the `analgesic ladder` for outpatient joint replacement: (1) pre-operative: oral celecoxib 400 mg + oral gabapentin 300 mg + oral paracetamol 1 g (given 1–2 hours before surgery — `pre-emptive analgesia`); (2) intra-operative: periarticular injection (PAI) of a long-acting local anaesthetic cocktail (bupivacaine or ropivacaine + ketorolac + adrenaline ± morphine) injected into the periarticular tissues at the time of closure — provides 12–24 hours of surgical site analgesia; adductor canal block for TKA (blocks the saphenous nerve — provides thigh and medial knee analgesia without motor block of the quadriceps — allows early mobilisation); (3) post-operative: scheduled paracetamol 1 g QDS + oral NSAIDs (naproxen or celecoxib) + oral oxycodone or tramadol PRN; IV opioids minimised to reduce nausea and drowsiness
• Adductor canal block vs femoral nerve block for TKA: femoral nerve block (FNB) was previously the standard for TKA analgesia but causes quadriceps weakness (falls risk, delays ambulation, incompatible with outpatient discharge); the adductor canal block (ACB) blocks the saphenous nerve (sensory only) within the adductor canal — provides equivalent pain control for TKA with preservation of quadriceps strength; ACB is the standard regional technique for outpatient TKA; the IPACK block (infiltration between the popliteal artery and capsule of the knee) is added to address posterior knee pain not covered by the ACB

• Enhanced recovery after surgery (ERAS) principles applied to outpatient joint replacement: pre-operative carbohydrate loading (clear carbohydrate drink 2 hours pre-operatively — reduces insulin resistance and post-operative nausea); nil by mouth minimisation (clear fluids until 2 hours, solids until 6 hours before surgery); intra-operative warming (forced air warming blanket — prevents hypothermia, reduces bleeding and infection risk); tranexamic acid (TXA — IV or topical/intra-articular; reduces blood loss by 30–50%; reduces transfusion rate; standard in outpatient joint replacement); minimal intraoperative fluid (avoid fluid overload — associated with nausea, delayed ambulation); minimally invasive surgical approach (muscle-sparing approach where possible)
• Discharge criteria (criteria-based discharge): the patient must meet ALL of the following before discharge — (1) pain controlled on oral analgesia (VAS ≤4/10); (2) able to mobilise independently with frame or crutches (assessed by physiotherapist — must demonstrate safe stair climbing for home discharge); (3) tolerating oral fluids and light diet; (4) voiding urine (urinary retention is a common cause of unplanned admission — treat with tamsulosin if not voiding within 6 hours); (5) vital signs stable; (6) wound dry (no excessive bleeding); (7) responsible adult escort at home confirmed; discharge is criteria-based, NOT time-based — if the patient does not meet criteria, they are admitted
• Unplanned admission: the rate of same-day unplanned admission in outpatient joint replacement programmes is approximately 5–15%; common causes — inadequate pain control, urinary retention, nausea/vomiting, hypotension, excessive wound bleeding, patient or carer anxiety; the ability to admit unplanned patients must always be available — outpatient joint replacement must not be performed without an inpatient safety net

• Equity and access concerns: outpatient joint replacement disproportionately benefits patients with strong social support, good health literacy, and high socioeconomic status; patients who are elderly, live alone, have language barriers, or have lower health literacy are less likely to be offered or to succeed with outpatient discharge; healthcare systems implementing outpatient joint replacement must actively address these equity concerns — enhanced pre-operative support, patient navigators, and community nursing visits post-discharge; failure to address equity risks widening health inequalities in access to joint replacement
• VTE prophylaxis in outpatient joint replacement: standard pharmacological VTE prophylaxis (aspirin 150 mg BD or LMWH or rivaroxaban) commences on the day of surgery and continues for 14 days (TKA) or 28–35 days (THA) as per NICE CG92 and BSSH guidelines; outpatient discharge does not modify the VTE prophylaxis duration; the patient must understand the importance of adherence to the VTE prophylaxis protocol post-discharge; early mobilisation is itself an important VTE prevention strategy
• Monitoring outcomes — the 90-day complication window: outpatient joint replacement programmes should track all 90-day outcomes (readmission rate, emergency department attendance, wound complications, DVT/PE, periprosthetic fracture, revision, and mortality) to ensure safety is maintained; registry data (NJR in the UK, AJRR in the USA) are being used to monitor the safety of outpatient joint replacement at a national level; surgeons and hospitals embarking on outpatient joint replacement programmes should benchmark their outcomes against published national standards

• Outpatient joint replacement: same-day or 23-hour discharge THA/TKA; requires careful patient selection (ASA I–II, good social support, BMI <40–45, motivated, cognitively intact); NOT for ASA IV, severe cardiorespiratory disease, morbid obesity, living alone
• SAFE criteria: Social support; Age/ASA; Functional status; Expectations (patient engagement); all four must be satisfied
• Low-dose spinal anaesthesia: hyperbaric bupivacaine 7.5–10 mg; motor recovery within 3–4 hours; essential for same-day discharge; standard dose (>15 mg) blocks motor function 6–8 hours — incompatible with SDD
• Adductor canal block (ACB): sensory block only (saphenous nerve); preserves quadriceps strength; replaces femoral nerve block for TKA; combined with IPACK block for posterior knee pain; enables early mobilisation
• Periarticular injection (PAI): long-acting LA + ketorolac + adrenaline ± morphine; injected at closure; 12–24 hours surgical site analgesia; cornerstone of multimodal outpatient analgesia
• Pre-operative optimisation: Hb ≥120 (F) / ≥130 (M); HbA1c <8.5%; BMI <40–45; smoking cessation ≥6 weeks; patient education (joint school); IV iron for pre-operative anaemia
• Tranexamic acid (TXA): reduces blood loss 30–50%; reduces transfusion rate; IV or topical/intra-articular; standard in outpatient joint replacement
• Discharge criteria (NOT time-based): pain VAS ≤4; independent mobilisation + stairs; tolerating diet; voiding urine; stable obs; dry wound; escort confirmed; urinary retention = most common cause of unplanned admission (treat with tamsulosin)
• Unplanned admission rate: 5–15%; pain, urinary retention, nausea, hypotension; inpatient safety net must always be available
• Equity: outpatient pathway must not widen health inequalities; actively support elderly, socially isolated, and lower health literacy patients