What the two approaches actually involve

"Surgical approach" refers to the route a surgeon takes through muscle and soft tissue to reach the hip joint — not the implant fitted inside it. The hip joint is a ball-and-socket structure: the rounded head of the femur sits in the cup-shaped acetabulum of the pelvis. In a total hip replacement (arthroplasty), both surfaces are replaced with a prosthetic implant. Roughly 58% of those implants are estimated to last 25 years.

The posterior (posterolateral) approach enters from behind the hip. The surgeon splits the gluteus maximus and temporarily detaches a group of short external rotator muscles — including the piriformis and obturator internus — to expose the joint. These tendons are repaired at the end of the operation.

The direct lateral approach (also called the modified Hardinge approach) enters from the outer side of the hip, splitting or partially detaching the gluteus medius and minimus from the greater trochanter — the bony prominence at the top of the femur.

The prosthetic components are the same either way. The two corridors differ solely in which soft tissues are moved, cut, or repaired, and it is that difference in tissue handling which produces their distinct risk and recovery profiles. Both have decades of registry data behind them; neither is universally superior for every patient.

Dislocation risk: what modern technique has changed

'Didn't the posterior approach have a high dislocation risk?' is one of the most common questions patients bring to consultation — and the historical concern was real. Before routine soft-tissue repair became standard, dislocation rates of 4–8% were documented with the posterior approach. The lateral approach, whose posterior capsule remains undisturbed during surgery, offered a natural restraint against backward displacement and carried much lower dislocation figures as a result.

What changed that picture is technique, not the approach itself. When surgeons began repairing the posterior capsule and reattaching the short external rotator tendons at the close of the operation, dislocation rates fell sharply. A meta-analysis by Sioen et al. (2017) quantified that shift precisely: the dislocation rate with soft-tissue repair was 0.49%, against 4.46% without — a roughly nine-fold difference driven entirely by whether the posterior soft tissues were reconstructed or left unsecured.

Muscle-sparing posterior modifications extend this progress further. The SPAIRE technique preserves the piriformis and obturator internus tendons intact rather than detaching and repairing them, reconstituting the posterior soft-tissue envelope more completely. One clinical consequence of that preservation is the elimination of the traditional 90° hip-flexion restriction — a precaution that existed to protect an unrepaired or vulnerable posterior capsule, and whose rationale disappears when the soft-tissue restraint is kept physiologically intact.

The lateral approach is not dislocation-free: anterior displacement can occur, even if infrequently. That remains a brief caveat rather than a symmetrical concern.

Patients who research this online will encounter the 4–8% figure frequently. It is historically accurate but describes an era of surgical practice that no longer reflects current technique at centres performing soft-tissue repair or muscle-sparing posterior approaches.

Abductor muscle disruption and the lateral approach

The gluteus medius is the muscle that keeps the pelvis level when walking. Each time you lift one foot off the ground, the gluteus medius on the standing side contracts to stop the pelvis from dropping toward the unsupported side. When that muscle is weakened, the pelvis dips visibly — a pattern called Trendelenburg gait — and the resulting limp can persist well beyond the immediate post-operative period.

This matters because the direct lateral (Hardinge) approach to hip replacement gains access to the joint by partially splitting or detaching the gluteus medius and gluteus minimus from the greater trochanter. Dissection that extends more than 3–5 cm proximal to the tip of the greater trochanter enters a danger zone for the superior gluteal nerve, the branch that innervates both muscles. Damage there — from stretch, retraction, or inadvertent division — produces exactly the abductor weakness described above.

The clinical scale of that risk is well documented. A 3D motion-capture study of 89 hip replacement patients found Trendelenburg gait in approximately 27% of cases at a mean of 1.3 years post-operatively. At a population level, the NIHR's analysis of 723,904 UK operations performed between 2003 and 2016 found that self-reported limping occurred twice as often following the lateral approach compared with the posterior or anterior approaches — a signal that held across more than a decade of registry data.

The nerve injury picture is not uniformly grim: most electromyographic changes in the superior gluteal nerve resolve spontaneously, and persistent clinical limp is a distinct and smaller subset. The management priority for lateral-approach patients is accordingly not a list of positional restrictions but a targeted abductor rehabilitation programme — structured work to rebuild gluteal strength and restore pelvic control during walking.

For context, the nerve risk profiles of the two approaches differ in character rather than simply in magnitude. The posterior approach carries proximity risk to the sciatic nerve, with consequences that would be more globally disabling were injury to occur. The lateral approach's specific risk is to the superior gluteal nerve, producing the narrower — but functionally significant — pattern of abductor weakness and limp.

Recovery, hospital stay, and post-operative restrictions

The most practical question for many patients at the decision stage is not which approach has the better long-term survival data, but what the first six weeks actually look like.

Traditional versus modern posterior-approach recovery

For decades, the posterior approach came with a strict restriction list: no hip flexion beyond 90°, no crossing of the legs, no low chairs or car seats — enforced for up to twelve weeks, often with a foam wedge pillow between the knees in bed. Those instructions existed because the posterior capsule and external rotators were left unrepaired or inadequately reconstructed. When soft-tissue repair became routine, and muscle-sparing modifications such as SPAIRE preserved the piriformis and obturator internus intact, the biomechanical rationale for those restrictions largely disappeared. Patients managed under modern precaution-free posterior protocols can sit in a standard chair from day one, travel in a normal car seat, and return to daily activities on a timeline that reflects wound healing rather than capsular vulnerability.

Lateral-approach recovery: no positional list, but abductor work

The lateral (Hardinge) approach imposes no comparable positional precautions. The recovery challenge here — as section three described in relation to gait — is rebuilding abductor strength. Physiotherapy is front-loaded with exercises targeting the gluteus medius; the functional goal is pelvic stability during walking rather than avoidance of specific movement planes.

Operative factors around the time of surgery

The posterior approach is generally faster and associated with lower intraoperative blood loss than the lateral. A fellowship-year comparison of direct lateral and direct anterior techniques found no statistically significant difference in hospital length of stay or opioid use between approaches, and both converged on equivalent HOOS scores at two-year follow-up — suggesting that, beyond the restriction profile, the practical recovery timeline differs less between approaches than patients might expect.

In a crossover cohort study of 69 patients who had staged bilateral hip replacement under different approaches, patients preferred the direct anterior technique over the lateral approach (72.5%) and over the posterolateral approach (60.7%), citing shorter hospital stay, earlier mobilisation, and shorter crutch dependence. That study does not directly compare posterior against lateral, but the pattern — that the lateral approach is consistently the least preferred on early-recovery grounds — is notable, and is consistent with the abductor-rehabilitation demands described above.

Which recovery profile suits a given patient depends on baseline muscle strength, body habitus, activity goals, and the surgeon's chosen technique — factors that a pre-operative clinical assessment is better placed to weigh than any single study.

Long-term outcomes and implant survival

However the first weeks unfold, the evidence consistently shows that the two approaches converge at one year. Comparative studies report no statistically significant difference in HOOS scores, leg-length discrepancy, or pain between posterior and lateral approach patients at twelve months and beyond, and all-cause revision rates are equivalently low across large registry datasets.

The NIHR's analysis of 723,904 UK operations does carry a persistent signal: the lateral approach was associated with significantly greater risk of re-operation and with self-reported limping at a population level. That finding is real, but the registry design cannot exclude case-selection confounding — surgeons may systematically choose the lateral approach for anatomically more complex hips, and it may be those complexities, rather than the surgical corridor itself, that drive the worse figures. It is a signal to weigh, not a verdict.

Long-term implant survival is shaped principally by implant design, fixation method, and patient-related factors such as age and activity level — not by which approach was used to place the prosthesis. Patients who develop lateral hip pain in the months or years following posterior-approach surgery should also be aware that greater trochanteric pain syndrome (GTPS) — bursal irritation over the greater trochanter — can be mistaken for implant-related failure. It remains underdiagnosed, and early discussion with the treating surgeon generally leads to straightforward management.

Across the published evidence, surgeon experience and case volume appear at least as influential on outcomes as the choice of approach — a point that reinforces the importance of specialist-led assessment before any surgical decision is made.

Which approach suits you — and who should decide

Three factors shape approach suitability more than any comparative trial can resolve: individual anatomy (acetabular orientation, BMI, and soft-tissue depth), the surgeon's trained volume in each technique, and the patient's activity goals and baseline muscle function. These variables require clinical assessment to weigh — no dataset substitutes for them.

The muscle-sparing posterior option

For patients being considered for a posterior approach, modern modifications have substantially changed what that corridor involves. The SPAIRE technique, originally described by Kim et al. (2008), preserves the piriformis and obturator internus tendons rather than detaching and repairing them at closure. Retaining these structures maintains natural posterior soft-tissue tension throughout surgery, supporting more accurate intraoperative assessment of leg length and femoral offset. The technique requires sufficient surgeon experience to be performed consistently, and not every anatomy is suited to it: significant deformity, acetabular retroversion, or cases where posterior exposure is technically limited may be better served by a different approach.

Distilling the evidence

The comparison reviewed across this article resolves into a directional pattern. Dislocation risk in the posterior approach is now principally determined by whether meticulous soft-tissue repair is performed: Sioen's meta-analysis found rates of 0.49% with repair versus 4.46% without. Abductor weakness and persistent limp remain the defining medium-term risk on the lateral side — Berstock et al. confirmed a significantly higher Trendelenburg gait rate versus the posterior approach, and the NIHR's analysis of 723,904 UK operations found self-reported limping at twice the frequency after lateral procedures. Those are signals worth knowing before any consultation, not verdicts — surgeon volume, case complexity, and individual anatomy continue to matter.

Objective gait measurement, through tools such as MAI Motion®, can establish a functional baseline ahead of surgery and inform both approach selection and rehabilitation planning. Professor Paul Lee's consultant-led assessments at Hip Replacement Lincolnshire — part of the MSK Doctors group — address precisely this kind of individual evaluation. Appointments are available without NHS-style referral at Sleaford (NG34) and Grantham (NG31); further information is at hipreplacementlincolnshire.co.uk.

1. [1] Direct anterior versus direct lateral hip approach in THA with the same perioperative protocols one year post fellowship training. (2023). https://doi.org/10.1186/s13018-023-03716-6 https://doi.org/10.1186/s13018-023-03716-6
2. [2] Post hip arthroplasty greater trochanteric pain syndrome following the posterior approach. (2026). https://doi.org/10.4103/ijhka.ijhka_28_25 https://doi.org/10.4103/ijhka.ijhka_28_25