What same-day and next-day discharge actually involves

For many patients considering hip replacement, the first practical question is straightforward: can I go home the same day? For a growing number, the answer is yes — though eligibility depends on factors that go well beyond simply wanting to leave early.

Same-day discharge (SDD) means leaving hospital on the same calendar day as surgery, typically within four to eight hours of the procedure. Next-day discharge involves a single overnight stay only. Both pathways sit a long way from the three-to-five inpatient nights that traditional hip arthroplasty routinely required — a length of stay driven by surgical technique and the recovery demands it imposed, not by the operation itself being inherently hazardous.

Real-world data confirm this shift is now mainstream rather than experimental. A prospective Danish multicentre study of 2,756 primary hip and knee arthroplasties found that 37% of patients were eligible for same-day discharge under a formal protocol; of those eligible, 52% went home on the day of surgery — representing 21% of all patients and a 15% absolute increase on the 2019 baseline. Patient experience supports the pathway too: 92% of outpatient arthroplasty patients in a qualitative study reported they would choose day-case surgery again over inpatient care.

Eligibility is not universal. Age, comorbidities, surgical approach, anaesthesia, and home circumstances all play a part. What has changed is the underpinning — minimally invasive techniques, tranexamic acid for blood management, and multimodal analgesia have together made same-day discharge clinically supportable in appropriately selected patients, with adverse event rates comparable to inpatient protocols. The sections that follow explain the specific factors — starting with the surgical approach itself — that determine which pathway a patient is likely to qualify for.

Why soft-tissue damage is the central variable

The hip joint's stability after arthroplasty rests not on the prosthesis alone but on the soft-tissue envelope surrounding it — the tendons, capsule, and muscles that hold the ball against the socket during ordinary movement. When surgery disturbs that envelope substantially, the body requires time to heal before it can resume its stabilising role. That healing window is what has historically shaped recovery demands after hip replacement.

Traditional posterior hip arthroplasty reaches the joint by dividing the short external rotator tendons — principally the piriformis and obturator internus — that attach to the back of the femur. This creates a biological vulnerability period of roughly 90 days while those tendons reattach and the posterior soft-tissue barrier gradually reconstitutes. During that window, the hip is susceptible to dislocation: 57% of patients who dislocate once experience at least one further dislocation, and 45.6% of those who dislocate require revision surgery within two years.

Those figures explain why the standard clinical response has been a strict set of hip precautions — no bending the hip beyond 90°, no crossing the legs, restricted rotation — enforced throughout the healing period. Protecting compromised tissue is the physiological rationale, and it is not arbitrary. The practical consequence, however, is that early mobilisation becomes difficult: patients cannot safely perform the weight-bearing transfers and stair tests that discharge criteria require while those restrictions are in place.

Approaches that preserve the posterior tendons intact substantially reduce this constraint. By removing or diminishing the healing-window vulnerability, they change the physiological basis on which discharge decisions are made — which is why surgical technique, rather than the operation itself, is the primary determinant of how soon a patient can safely go home.

How SPAIRE changes the recovery timeline

SPAIRE — Saves Piriformis And (Obturator) Internus with Repair of (Obturator) Externus — modifies the standard posterior approach by working around the posterior tendons rather than dividing them. The piriformis and obturator internus are left structurally intact. Without division, there is no healing window to protect and, consequently, no physiological basis for the hip precautions that have historically extended inpatient stays after conventional posterior surgery.

Two distinct mechanisms explain how stability is maintained from the outset without requiring patient movement restrictions.

The strap effect. The intact obturator internus tendon courses over the posterior femoral head, creating a dynamic biological tether — a passive 'strap' that resists posterior subluxation during ordinary movement. This is not a repaired structure under load; it is an undisturbed anatomical structure performing its normal function. Patients do not need to restrict movement to protect it, because it was never disturbed in the first place.

Proprioceptive continuity. Embedded within those intact tendons are Golgi tendon organs and muscle spindles — mechanoreceptors that relay continuous position and load information to the central nervous system. Traditional posterior approaches sever these structures, leaving the hip neurologically dependent on compensatory pathways until tissue regeneration restores the feedback loop. In SPAIRE, that neural circuit remains unbroken from the first day of recovery. The proprioceptive rationale is mechanistically well-grounded; comparative trial data isolating this specific outcome remain limited.

Together, these properties mean patients can perform the weight-bearing transfers and functional mobility tests that discharge criteria require far sooner than conventional posterior surgery allows.

This is the clinical foundation underlying Prof Paul Lee's biological rapid recovery programme, which treats surgical technique as one component within an integrated pathway — combining approach, implant selection, mobilisation protocol, and post-discharge planning. Same-day or next-day discharge becomes a realistic outcome for selected patients rather than an exception. Patient suitability remains central to the decision, and individual assessment determines which recovery route is clinically appropriate.

The direct anterior approach: genuine advantages and honest trade-offs

Unlike the posterior approach, the direct anterior approach (DAA) reaches the hip joint by working between existing muscle planes rather than dividing them. Because no posterior tendons are cut, hip precautions are unnecessary — patients can flex, cross, and rotate without restriction from day one. Early Harris Hip Scores at six and twelve weeks have favoured DAA in some series, reflecting genuine short-term functional gains that a well-selected patient may notice.

The trade-offs, however, are specific and worth understanding plainly. The lateral femoral cutaneous nerve (LFCN) runs close to the anterior incision site; neurapraxia — numbness or tingling across the outer thigh — is a recognised risk that can persist long after the wound has healed. Intraoperative fracture of the femoral shaft is a further concern, occurring more frequently during the learning curve than with approaches that give the surgeon broader visualisation of the femur. The DAA also requires fluoroscopy or navigation equipment and a specialist operative table; not all surgical environments support this routinely.

A 2025 randomised controlled trial, recognised with the John Charnley Award, compared anterior and lateral approaches in hemiarthroplasty for femoral neck fracture. On Barthel score, EQ-5D, pain, length of stay, and 90-day readmission and mortality, the groups were indistinguishable. The finding matters for how discharge-timing claims are assessed: the approach alone, without the surrounding Enhanced Recovery After Surgery infrastructure — anaesthesia type, multimodal analgesia, mobilisation protocol, and post-discharge planning — does not independently accelerate recovery or discharge.

DAA and soft-tissue-preserving posterior techniques such as SPAIRE occupy different risk profiles rather than a hierarchy. Which is appropriate depends on individual anatomy, surgeon experience, available equipment, and the full pathway a centre can reliably deliver around the procedure. Patient assessment and consultant-led planning remain the deciding factors.

Patient suitability: what determines eligibility for early discharge

Eligibility for same-day discharge is assessed, not assumed — and a structured assessment considers more variables than many patients anticipate.

The Outpatient Arthroplasty Risk Assessment (OARA) score is the most established tool: scores between 0 and 79 carry a 99.3% specificity for predicting successful discharge on the day of surgery, outperforming the broader ASA classification. A 2022 study of 1,332 arthroplasty cases found the tool may nonetheless be conservative — 97% of patients formally categorised as 'unacceptable' under OARA criteria still achieved same-day discharge, suggesting simpler selection methods may be equally practical in experienced settings.

Standard exclusion criteria centre on recovery capacity at home rather than surgical risk itself. Age over 80, clinically significant cardiac disease, end-stage renal disease, and active bleeding disorders are the principal contraindications — these affect how safely a patient can manage the early post-operative hours independently, not whether the procedure itself can be carried out safely.

Body weight is not the barrier many patients expect. A retrospective series of 15,133 arthroplasties found that patients with a BMI of 40 kg/m² or above achieved same-day discharge without significantly higher early complication rates than non-obese same-day patients. Within the obese cohort, those who went home on the day of surgery averaged four years younger than obese patients who stayed overnight — suggesting age carries more weight than BMI alone when determining suitability.

Preoperative education and post-discharge support are structural requirements of any same-day pathway, not optional additions. Patients who understand what to expect, can recognise red-flag symptoms, and have a clear route to clinical contact in the first 24 hours are more confident going home early and demonstrably safer. A thorough assessment evaluates whether those conditions are in place for each individual, not only their clinical parameters.

Getting an assessment and deciding on an approach

Taken together, the variables described in this article — soft-tissue preservation, approach selection, physiological eligibility, and post-discharge infrastructure — converge in a single pre-operative assessment. That consultation is where the discharge trajectory is effectively set, not on the ward the morning after surgery.

A thorough assessment considers how anatomy, functional goals, comorbidities, and implant choice interact for each individual. Whether a soft-tissue-sparing posterior technique such as SPAIRE, the direct anterior approach, or a different method is appropriate depends on that specific combination — not on a blanket preference for one technique over another. This is a clinical judgement that no questionnaire or GP summary letter can substitute for.

Hip Replacement Lincolnshire, part of the MSK Doctors group, offers consultant-led assessment at Sleaford (NG34) and Grantham (NG31) without the need for a GP referral and without NHS-style waiting lists. Prof Paul Lee, whose clinical approach to soft-tissue-preserving hip arthroplasty underpins the SPAIRE-based pathway described throughout this article, leads assessment and surgical planning for selected patients.

Patients can book a direct assessment — without a referral — at hipreplacementlincolnshire.co.uk.

1. [1] Implementation of outpatient hip and knee arthroplasty in a multicenter public healthcare setting. (2024). https://doi.org/10.2340/17453674.2024.40185 https://doi.org/10.2340/17453674.2024.40185
2. [2] Outpatient Joint Arthroplasty — Patient Selection: Update on the Outpatient Arthroplasty Risk Assessment Score. (2019). https://doi.org/10.1016/j.arth.2019.01.007 https://doi.org/10.1016/j.arth.2019.01.007
3. [3] Is an 'Outpatient Arthroplasty Risk Assessment Score' needed for predicting safe selection of outpatient arthroplasty candidates?. (2022). https://doi.org/10.1016/j.arth.2022.08.024 https://doi.org/10.1016/j.arth.2022.08.024
4. [4] Effect of anterior approach compared to posterolateral approach on readiness for discharge and thrombogenic markers in patients undergoing unilateral THA: a prospective cohort study. (2022). https://doi.org/10.1007/s00402-022-04484-4 https://doi.org/10.1007/s00402-022-04484-4
5. [5] Patients' Perceptions and Experiences With Outpatient Hip and Knee Arthroplasty: A Qualitative Study. (2025). https://doi.org/10.7759/cureus.78781 https://doi.org/10.7759/cureus.78781
6. [6] Outpatient Hip and Knee Arthroplasty in Obese Patients With BMI Above 40 kg/m² is Not Associated With Increased Early Complication Rates. (2025). https://doi.org/10.1016/j.artd.2025.101785 https://doi.org/10.1016/j.artd.2025.101785
7. [7] The John Charnley Award: The Anterior Approach Does Not Improve Recovery after Hemiarthroplasty for Femoral Neck Fracture. A Randomized Controlled Trial.. (2025). https://doi.org/10.1016/j.arth.2025.04.030 https://doi.org/10.1016/j.arth.2025.04.030