Why the surgical approach changes your recovery

The approach your surgeon uses does matter — but perhaps not in the way most patients expect. The implant itself (the artificial ball and socket that replaces the worn joint) is largely the same regardless of which direction the surgeon enters. What differs is the path taken to reach it, and specifically which muscles and tendons are disturbed along the way.

The hip is a ball-and-socket joint: the rounded head of the thigh bone (femur) sits inside a cup-shaped socket (acetabulum) on the pelvis. Wrapped around the back of this joint is a group of small but functionally important muscles — the short external rotators, which include the piriformis and obturator internus. Think of them as a protective cuff at the rear of the hip, similar in role to the rotator cuff of the shoulder. These tendons help stabilise the joint, guide movement, and feed the brain continuous positional information about where the leg is in space.

Different surgical approaches disturb this cuff to different degrees. Some techniques detach tendons to gain access, then repair them at the end of the operation. Others work between muscle planes without cutting them at all. That distinction drives real differences in the post-operative experience: how soon a patient can walk without restrictions, whether strict movement precautions are needed for several weeks, and how the joint is stabilised against dislocation in the early weeks.

Approach choice also affects the surgeon's view of the joint during the operation, the risk of temporary nerve symptoms, and — particularly for some techniques — the requirements on operating equipment and the surgeon's own training.

None of this makes one approach universally better than another. Surgeon familiarity and experience carry at least as much weight as the technique's theoretical merits, and individual factors such as patient build, BMI, bone quality, and previous surgery all shape which approach is appropriate. Over the longer term, approximately 58% of hip implants survive 25 years, and that figure reflects implant design and fixation far more than which direction the surgeon entered. Where the approach has its clearest influence is on the weeks immediately after surgery — and that is what the comparisons below set out to explain.

Posterior approach — the most widely used technique

Roughly half of all hip replacements performed in the UK use the posterior approach, and its longevity at the top of that table is not arbitrary. The technique gives the surgeon a wide, unobstructed view of the acetabulum and femoral head — an advantage that translates into reliable implant positioning and decades of registry-backed long-term data.

Access is gained through a curved incision along the back of the hip. To reach the joint, the surgeon divides the short external rotator tendons — the piriformis and obturator internus — and opens the posterior capsule. This gives excellent exposure but temporarily weakens the very structures that hold the prosthetic head in position. It is this weakening, not any fault in the operation itself, that drives the traditional requirement for hip precautions: no bending the hip beyond 90°, no crossing the legs, no low chairs for approximately six weeks while the tendons heal and the capsule regains strength. The precautions are a sensible biological guard, not a sign that something went wrong.

Modern posterior variants address this directly. Techniques such as STAR (short external rotator repair) formally repair the capsule and tendons at the end of the procedure, restoring tension more quickly and, in many cases, removing the need for strict restrictions altogether. Long-term implant survival with the posterior approach remains well-established in large registry datasets, and it continues to be the benchmark against which newer techniques are measured.

The logical next step for surgeons has been to ask whether the external rotators need to be divided at all — and several newer approaches have been built around that question.

Lateral approach — lower dislocation risk, higher revision rate

Reaching the hip from the side — the Hardinge or direct lateral approach — means splitting the gluteus medius and gluteus minimus muscles rather than the posterior rotator tendons. Because the back of the joint is left untouched, the prosthetic head is less likely to slip backwards, and the lateral approach has long been associated with one of the lowest dislocation rates of any technique.

The trade-off is the gluteus medius itself. Splitting this muscle can produce a temporary weakness that throws the pelvis off-level when walking — a pattern clinicians call Trendelenburg gait. For most patients this resolves over weeks to months, but it is a recognised feature of the recovery that the posterior and anterior routes largely avoid.

More significantly, a UK registry analysis of 723,904 hip replacement operations carried out between 2003 and 2016, summarised by the NIHR, found that lateral procedures were associated with more post-operative deaths and a greater risk of revision surgery than either the posterior or anterior approaches. The researchers concluded that new surgeons should be trained in other techniques. That is a specific, registry-scale finding from an unusually large dataset, and it sits poorly against the approach's principal selling point. A low dislocation rate is a meaningful benefit; the evidence suggests it does not offset the broader outcome picture.

Direct anterior approach — no muscle division, steeper learning curve

At the front of the hip, a natural anatomical gap runs between the tensor fasciae latae and sartorius muscles — a plane that also sits between two separate nerve territories. The direct anterior approach (DAA) works entirely within this interval. Because no muscle fibres are cut or detached from the bone, the surgical trauma is substantially reduced and the joint's supporting structures remain intact from the outset.

This is what surgeons mean by an intermuscular, internervous approach, and it is the basis for the DAA's principal clinical benefit. Without muscle damage to recover from, patients typically mobilise on the day of surgery and are not subject to the movement restrictions — no bending beyond 90°, no leg-crossing — that characterise the conventional posterior route. In the early weeks, functional improvement often proceeds faster than after a standard posterior approach.

Surgeon experience and equipment are real constraints. The posterior approach is technically forgiving across a wide range of body types; the DAA is not. Most surgeons using this technique require a specialist traction table to position the femur during implantation, and the exposure becomes significantly more demanding in patients with a high BMI, particularly muscular thighs, or previous surgery on the same hip. Patients can reasonably ask how many anterior procedures their surgeon performs each year.

A smaller but worth-noting issue is temporary numbness or tingling at the front of the thigh, caused by stretch on the lateral cutaneous nerve of the thigh during retraction. This usually resolves within weeks to a few months.

By three to six months, outcome data broadly converge with the posterior approach. The DAA's edge is front-loaded in the recovery window — significant for many patients, but not a lasting difference in joint function over years.

SPAIRE hip replacement — keeping all key tendons intact

SPAIRE — Saves Piriformis And Internus, Repairs Externus — is a modified posterolateral approach in which none of the major rotator tendons at the back of the hip are divided. Where the standard posterior technique detaches the piriformis and obturator internus to gain access, SPAIRE works around these structures entirely, leaving them attached and under their natural tension throughout the procedure.

The clinical perspective behind this site comes from Professor Paul Lee, whose routine practice in hip replacement centres on the SPAIRE technique — an approach refined through specialist training under Professor Timperley at the Exeter Hip Unit.

The key mechanical consequence of preserving these tendons is what the literature describes as the 'strap effect'. The obturator internus tendon, left undisturbed, passes directly across the back of the prosthetic femoral head — functioning rather like a natural seatbelt across the ball of the joint. This biological tether resists posterior dislocation of the implant, which is why patients treated with SPAIRE are not given the six-week movement restrictions that follow the conventional posterior approach. Stability is provided by anatomy rather than by instruction.

Beyond the mechanical, the preserved short external rotators retain their Golgi tendon organs and muscle spindles — the sensors that tell the brain where the hip is positioned. Conventional posterior approaches sever these receptors; SPAIRE leaves them intact, which may provide an additional layer of stability through continuous proprioceptive feedback.

Keeping the posterior soft tissues under natural tension also gives the surgeon a reliable tactile guide to leg length and femoral offset during implantation. The technique integrates with Mako robotic-arm assistance where this is used, adding sub-millimetre precision to bone resection and component positioning.

For suitable patients, these features translate into clear practical outcomes: no post-operative movement precautions, mobilisation with crutches on the day of surgery, and — where anatomy and overall health allow — same-day or next-morning discharge. Individual anatomy and health still determine whether SPAIRE is the right fit, and a consultant assessment is the starting point for that decision.

SuperPATH, patient suitability, and how approach choice is made

Unlike every other approach described here, SuperPATH removes the femoral head without the hip joint ever being fully dislocated. Working entirely above the capsule through an incision of roughly 2–3 cm, the surgeon achieves access without cutting any muscles or tendons and without the joint moving out of position at any point — which is why the technique is classified as supracapsular. Post-operative movement restrictions are not required.

The comparison with SPAIRE is not a ranking of one technique over another. Both preserve soft tissues; both support early mobilisation and eliminate the six-week precaution period that follows conventional posterior surgery. The structural difference lies in how access is gained: SPAIRE still dislocates the hip to achieve the exposure its approach requires, whereas SuperPATH does not. For a given patient, the choice turns on which method gives the safest, most accurate view for implant placement — anatomy first, preference second.

Several individual factors inform that clinical judgement: soft-tissue bulk, bone quality, the geometry of the patient's hip anatomy, and whether previous surgery has altered the joint's normal architecture. The surgeon's depth of experience with each technique carries as much weight as any of these considerations.

Direct head-to-head trial evidence comparing SPAIRE, SuperPATH, and the anterior approach in the same populations remains limited; most data come from registry analyses or observational series. No published league table currently resolves the choice between the newer soft-tissue-preserving techniques. What the evidence does consistently indicate is that preserving posterior soft tissues — by whatever route suits the individual — is associated with faster early recovery and lower dislocation risk than approaches that divide the key tendons.

The practical takeaway for a patient reaching this stage of the decision is not which approach wins a comparison article, but which approach suits their anatomy and is available from a surgeon who performs it regularly and in volume. That question requires individual clinical assessment — a review of imaging, body composition, joint geometry, and functional goals — rather than a universal recommendation.