Sciatic Nerve Palsy After Hip Replacement

What Works

Worth saying plainly before the list: no treatment for this condition has ever been tested against a comparator. Nothing below reaches strong evidence, and the gradings describe how well supported it is that the action is appropriate, not proof that it beats an alternative.

Tier 1 · The strongest tier this condition has

Imaging, to rule out something pressing on the nerve.Moderate
A pelvic CT scan checks the position of the new joint and looks for a blood collection. An MRI with a metal-suppression setting looks at the nerve itself. This is the step that changes what happens next, and it is described as mandatory once a palsy is diagnosed.

An ankle-foot orthosis (brace).Moderate
The single most useful thing available. It holds the foot up so you can walk without catching your toes, from the day it is fitted. Universal practice across every published series, though never actually trialled against an alternative. In the landmark study, 15 of 47 patients needed one permanently.

Nerve testing at 3 to 6 weeks, if nothing is improving.Moderate
EMG and nerve conduction studies establish the level and severity. The recommendation is specifically against testing earlier, or in someone who is already improving.

Protecting ankle movement.Moderate, extrapolated
Keeping full passive ankle movement stops the ankle stiffening into a fixed pointed-down position while you wait. Borrowed from general foot drop care rather than from this condition's own literature, and flagged as such, but the reasoning holds: with recovery running for months to years, a preventable stiffness would outlast the nerve injury itself.

Exercise Prescription

Read this first. These are borrowed from general foot drop and nerve injury rehabilitation. No research has tested any exercise programme for this specific problem, so treat them as sensible protection rather than proven treatment. The well-supported parts of your plan are the brace, the ankle range, falls safety, and knowing the warning signs.

Calf and Achilles stretch with a towel

3 × 30 second holds · 3× daily

Sit with the leg straight, loop a towel around the ball of the foot and pull the toes gently toward you. The most important one on the list, because it is what stops the ankle stiffening while you wait.

Assisted ankle movement

2 × 15 · twice daily

Use your hand or the towel to move the foot up and down through its full range, even if the muscles cannot do it yet. You are keeping the joint free, not building strength.

Active lift attempts

2 × 10 · twice daily

Try to lift the foot and toes yourself. If nothing moves, still try. A flicker of movement is the thing to report to your therapist.

Supported standing balance

3 × 30 seconds · daily · always hold on

Stand at a kitchen counter, hold on, and shift weight gently side to side. This is falls prevention rather than strength work, which is why the hand stays on the counter.

Tier 2 and 3 · weaker and consensus-only

Structured physical therapy (ankle strengthening as the nerve recovers, gait retraining, falls prevention). Consensus only
Named as a mainstay of care in a 2026 review, with no controlled trial of any kind behind it. The only paper naming rehabilitation intensity as an outcome factor studied 6 patients.

Neuropathic pain treatment. Consensus only
Burning or shooting pain is treated separately from the weakness. 5 of 47 patients in the landmark series needed daily medication for it long term.

Falls risk assessment. Weak
Inferred from how often it was needed rather than measured: 21 of 47 patients required walking aids.

Surgical exploration or decompression where a compressive lesion is found. Emerging
The pooled reoperation rate is 33.1%, with a confidence interval running from 4.2% to 62.0%. An interval spanning almost the entire possible range means the field has no shared practice at all.

What doesn't work

Waiting to scan. A delayed compressive palsy looks identical to a stretch palsy on examination, and it is the one with a closing window.
Running the hip replacement's clock. That protocol runs in weeks. This runs in months to years. A programme built on the wrong clock declares failure long before a nerve could have recovered.
Examining only the outside of the knee. Nerve testing often localises the damage near the knee while the cause sits up at the hip. A normal examination there rules nothing out.
Hammering a denervated muscle with strengthening work. Nothing supports it, and it displaces the two things that do matter: protecting movement and preventing falls.
Promising recovery. Depending on the study and how recovery is defined, somewhere between 20% and two-thirds of people recover fully.

Dark cinematic study of an ankle and foot in low light

Red Flags

Most of these need your surgical team the same day, not your next scheduled appointment.

Get checked urgently

Weakness that appeared later, after your foot had been working normally. That pattern points to bleeding, a prominent screw or swelling pressing on the nerve, not a stretch injury.
Weakness that is deepening rather than staying the same.
Severe or disproportionate pain, or a tense, swollen limb.
Any new foot drop that has not been scanned. Imaging is described as mandatory once a palsy is diagnosed, because the treatable causes are only visible on a scan.
No improvement at all by 3 to 6 weeks. This is the point at which nerve testing is recommended.
Numbness around the back passage or genitals, or any change in bladder or bowel control. Emergency.
A pale, pulseless or tensely swollen leg. Emergency.

Refer to: the operating orthopaedic surgeon urgently for anything delayed, worsening or painful, because the window for fixing a compressive cause is time-limited. Neurology or clinical neurophysiology for nerve testing at 3 to 6 weeks. A&E for bladder, bowel or circulation signs.

Dark cinematic anatomical study of the posterior hip and sciatic nerve

Return to Training

The organising principle here is unusual and worth stating plainly: the restriction is falls risk from a foot that will not clear the ground, not fragile tissue. Exercise does not damage the nerve further. Upper-body and supported lower-body work can usually continue at full load, with the standard hip replacement precautions still applying in full.

Compressive cause ruled out by imaging, documented
Brace fitted, tolerated, and skin checked underneath
Full passive ankle movement maintained, with no fixed stiffness
Ankle lift strength at grade 4 of 5 or better, or a reliably braced foot with demonstrated clearance
Can walk 500 m over uneven ground with no trip or stumble
Single-leg stance held 10 seconds unsupported, before any unsupported single-leg loading
No loss of strength grade over 4 consecutive weeks
Standard hip replacement return criteria independently met
Falls risk assessed and home hazards dealt with

What to stop now: anything needing foot clearance or unsupported single-leg balance. Walking lunges, step-ups, box work, jumping, running, and heavy standing barbell work where a stumble is dangerous. What to keep: upper-body work at full load, machine and seated lower-body work at full load, and the hip's own prescribed rehabilitation. Bring clearance-dependent movements back last.

Answer one question right now: was your foot weak the moment you woke up from surgery, or did it show up later? If it showed up later, or it is getting worse, call your surgical team today and ask about a scan. Do not wait for your next appointment.

This single question separates the kind that time treats from the kind that needs fixing quickly.

Takes 10 seconds

The Verdict

A hip replacement can stretch the nerve that lifts your foot. When it started tells you what to do.

Think of the nerve as a phone cable pinned at both ends, once behind your hip and again beside your knee. Lengthening the leg pulls the slack out of it, and the thinnest strand inside, the one running to the muscle that lifts your foot, is the first to stop carrying a signal. It has to regrow along its whole length rather than simply heal over, which is why recovery here is counted in months and sometimes years instead of weeks.

What this actually is: a nerve behind your new hip was stretched or pressed during the operation, and the strand that lifts your foot is the one that fails first.
What most people get wrong: resting does not speed this up, and the real daily danger is tripping over a foot that will not lift, so a brace and a trip-proofed house matter more than exercises.
What to watch for: if the weakness appeared days after surgery rather than immediately, or is getting worse, something may be pressing on the nerve and that needs a scan the same day.

Best for

Anyone recovering from a hip replacement whose foot or ankle feels weak, and anyone waiting on one who wants to know what to watch for.

Skip if

Your weakness came on late, is getting worse, or comes with severe pain and swelling. That needs your surgeon today, not a web page.

Want the full evidence? Keep scrolling

Conviction

Moderate Stratified, because the evidence is genuinely uneven across this page. How common it is, which part of the nerve fails, and the fact that recovery is often incomplete are all well established. The exact recovery percentage is not, and there is no evidence at all behind any specific exercise programme, which is a different statement from weak evidence.

Claim	Confidence
How common it is (roughly 0.3% to 0.4%)	High
The foot-lifting division fails first	High
Recovery is frequently incomplete	High
Recovery runs months to years	Moderate
Back trouble as a risk factor	Moderate
Late or worsening weakness means compression	Moderate
Any specific recovery percentage	Low
A safe limit for how much the leg is lengthened	Low, and negative
Any exercise programme	No evidence

What would change my mind on the lengthening question

A prospective multicentre study of at least 2,000 hip replacements measuring how far the nerve actually moves during surgery, rather than how much the leg lengthened on an X-ray, set against a difficulty score recorded before the operation. If nerve movement predicts palsy once operative difficulty is held constant, a 40-year stalemate breaks. If it does not, lengthening should be retired as a cause and named what it probably is: a marker for the difficult hip.

What would change my mind on rehabilitation

A multicentre randomised trial of at least 120 patients with confirmed palsy after hip replacement, comparing a structured programme (brace, progressive loading, gait retraining) against usual care, measuring ankle strength and independent walking at 12 months. At this condition's rate you would need roughly 33,000 hip replacements to recruit from, which is exactly why it has never been done, and why building it into a national joint registry is the only realistic route.

Next step

Most people only find out a complication like this exists after it has happened to them. The Verdict sends one evidence-checked protocol a week, written the same way as this page: what the research actually supports, and where it runs out.

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The Full Picture — Anatomy, Diagnosis & Evidence

What's Actually Going On

The sciatic nerve leaves the pelvis at the sciatic notch, passes behind the hip joint, and runs down the back of the thigh before splitting into two divisions. It is anchored at the top and again around the outside of the knee. Anything that increases the distance between those anchor points, or presses on the nerve along the way, produces the same weak foot.

Four mechanisms produce that picture, and telling them apart is the whole clinical task, because two are emergencies and two are not.

Traction from lengthening the limb. Restoring length to a hip that has been short for years stretches a tethered nerve. This has dominated the literature since 1987, and the evidence for it as an actual causal dose is far weaker than its prominence suggests.
Direct surgical trauma and retractor pressure. Posterior retractors sit close to the nerve. Together with traction, this produces the deficit that is present immediately on waking.
Delayed compression: a blood collection, a prominent screw, or a pseudotumour. This produces the deficit that appears later, and it is the group where acting quickly changes the outcome.
A nerve already under pressure elsewhere. Pre-existing lumbar spine disease carried an odds ratio of 21.3 (95% CI 2.8 to 163.1) in the best modern study, a double-crush effect where a nerve root already compromised in the back tolerates a second insult badly.

Why the foot, and not the hamstring. The peroneal division was affected in 68% of palsies, against 18% for the whole nerve. It has fewer, larger bundles inside it, less protective packing, and it is tethered at the knee, so it is the part that fails whenever the sciatic nerve is stressed anywhere along its length. The knee replacement literature reaches the same conclusion by a completely separate route, which is what makes it trustworthy: the vulnerability belongs to that division of the nerve, not to either operation.

Dark cinematic anatomical rendering of the sciatic nerve pathway behind the hip

How to Identify It

There is no validated special test for this condition, and that is a finding rather than a gap in this write-up. No test with published sensitivity or specificity exists. The diagnosis is made from the history, the pattern of weakness and numbness, and imaging. Any table of test accuracy figures offered for this condition elsewhere should be treated as invented.

The pivotal question: was the foot working when you first woke up after the operation? This separates a stretch injury from a compressive one.
Manual muscle testing graded 0 to 5: ankle lift, big toe lift, turning the foot outward, pushing down, turning inward. The pattern, not any single grade, gives the diagnosis.
Sensory mapping separating the deep division (first web space), the superficial division (outer shin and top of foot), the tibial division (sole), and an L5 nerve root pattern.
Signs the whole nerve is involved rather than just the foot-lifting division: weak push-off, absent ankle reflex, numbness in the sole. This carries a worse outlook.
Nerve conduction studies and EMG at 3 to 6 weeks, and only if nothing is improving. Timing is the recommendation here, not the test itself.

The differential that matters most is a compressive cause: delayed or progressive onset, often with severe pain and swelling. That one is answered by a scan, not by an examination. Also worth separating: a femoral nerve palsy from the same operation (weak knee straightening, reduced knee reflex, better outlook), an L5 nerve root problem, and a pre-existing neuropathy affecting both legs.

Dark cinematic clinical study of a lower limb examination

The Debate

No clinical practice guideline exists for this condition as of August 2026. The most authoritative statement available is a 2026 current-concepts review, which is expert consensus rather than a graded guideline. So these are conflicts between older and newer evidence, not between a guideline and a trial.

Is lengthening the leg what causes it?

Edwards 1987 · Farrell 2005 · Seward 2026

Lengthening is significantly associated with palsy across 27,004 hip replacements. 39 of 40 affected patients had been lengthened, a median of 10 mm against 3 mm in matched controls. Average lengthening was graded by severity: 2.7 cm for a foot-lifting palsy, 4.4 cm for a full sciatic palsy.

Eggli 1999 · De Fine 2017

In 508 dysplastic hips, the population where lengthening is greatest, there was no correlation at all between the amount of lengthening and nerve palsy (p=0.47). What did correlate was how difficult the surgeon rated the operation (p=0.041), present in 7 of 8 cases. A systematic review of 14 studies concluded no hazardous threshold can be identified.

Lengthening is strongly associated with palsy and is also a marker for the difficult hip. It is not a dose with a safe ceiling, and forty years of research have not produced a number of millimetres above which a surgeon should stop. Nobody should be told their palsy was caused by a specific measurement.

How many people actually recover?

De Fine 2017 · Alturki 2026 · Slaven 2023

Roughly two-thirds achieve full restoration, independent of how bad the initial damage was. Pooled complete recovery across 17 studies was 48.6% (95% CI 33.9 to 63.3). Full motor recovery 58% to 60%.

Seward 2026 · Farrell 2005 · Coden 2024

Only 20% had complete motor recovery, over a mean of 28 weeks. Among complete palsies, 36% fully recovered, taking an average of 21.1 months. Almost complete recovery in just 4 of 17 patients.

A three-fold spread, and it is not measurement noise. The pessimistic series demand objective weakness, follow people for years, and include complete palsies; the optimistic figures pool studies with mixed severity and shorter follow-up. Recovery rate is mostly a statement about who got counted, which is why quoting a bare percentage transmits false precision.

Does the surgical approach protect you?

Slaven 2023

The direct anterior approach had a lower overall palsy rate than posterior, 0.24% against 0.52% (p=.02), across 10,047 hip replacements.

Coden 2024 · Seward 2026

For sciatic palsy specifically there was no difference: 0.17% anterior against 0.11% posterior (p=0.5). Approach was not significant on multivariable analysis.

These do not actually conflict, they measure different things. Approach changes which nerve gets injured more than whether one does. Anterior produces 4.3 times more femoral than foot-lifting palsies; posterior produces 8 times more foot-lifting than femoral.

Honest Limitations

There is no rehabilitation literature to translate

The research: physical therapy is named as a mainstay of non-surgical management in a 2026 review in a major journal.

The gap: it is supported by zero controlled trials. The only paper naming rehabilitation intensity as an outcome factor has six patients. This is an absence of evidence, which is a different claim from weak evidence and should not be dressed up as a low grade.

The adjustment: deliver rehabilitation as standard care and say out loud that it is consensus-based. Put the confident claims where the evidence actually is: recognition, triage, protection and timeline.

Every recovery percentage is an artefact of who was counted

The research: complete recovery is reported anywhere from 20% to two-thirds.

The gap: that spread comes from case definition and follow-up length, not from different treatments or different populations responding differently.

The adjustment: never quote a bare percentage. Say which population and which follow-up produced it, and give the honest range.

The surgical literature answers surgical questions

The research: nearly every study here was designed to inform operative decisions. Which approach, how much lengthening, which implant.

The gap: what to load, when, how to progress and what the milestones are were never study endpoints. Their absence reflects what researchers chose to study, not a failure of rehabilitation.

The adjustment: borrow from general nerve injury and foot drop care, and label the borrowing every time it appears.

The Nuance

This is not really a surgery-versus-conservative decision, and framing it as one misleads people. The decision is compressive versus non-compressive, and it is answered by a scan rather than by preference. Where something is pressing on the nerve, decompression is the pathway and the window is time-limited. Where nothing is, there is nothing to operate on, and the supportive pathway is the default by absence rather than by evidence. No study has ever compared surgical against conservative management here.

The uncomfortable part of the numbers is the disability tail. Of 47 patients in the landmark series, 21 needed walking aids, 15 needed a permanent ankle brace, and 5 needed daily medication for chronic nerve pain. Pooled permanent impairment across 17 studies was 39.8% (95% CI 25.1 to 54.4). Someone told this is "usually temporary" has been told something the two most recent large series do not support.

The most under-appreciated risk factor is one you can see before the operation. Lumbar spine disease carried an odds ratio of 21.3, the largest effect anyone has measured here, corroborated independently across 39,056 hip replacements. The confidence interval runs from 2.8 to 163.1, so the direction is solid and the exact magnitude is not, but it is checkable in advance and it is not routinely checked.

And a note on how this field got here. Limb lengthening is named as the cause in most reviews of this complication. It was never shown to have a hazardous threshold, and it lost its correlation entirely in the one population where it is largest, where operative difficulty predicted instead. The measurable proxy, millimetres on a radiograph, displaced the harder-to-measure real variable, how difficult the operation actually was, because one is a number and the other is a judgement.

Dark cinematic anatomical study of the lower limb and nerve pathway

Sources

Alturki A, et al. (2026). Nerve Injuries After Total Hip Arthroplasty: A Systematic Review and Meta-Analysis. Orthopedic Reviews. PMID 42040246. 17 studies pooled. Incidence 0.36% (95% CI 0.35 to 0.37), complete recovery 48.6%, permanent impairment 39.8%.
Farrell CM, et al. (2005). Motor nerve palsy following primary total hip arthroplasty. J Bone Joint Surg Am. PMID 16322610. The landmark series. 47 palsies in 27,004 hip replacements. Complete-palsy recovery 36% over a mean 21.1 months; 15 permanent braces.
Seward MW, et al. (2026). Motor Nerve Palsy After Primary Total Hip Arthroplasty: A Case-Control Analysis With Radiographic Review. J Arthroplasty. PMID 40935346. 40 palsies in 10,604 hip replacements. Lumbar spine disease OR 21.3 (95% CI 2.8 to 163.1). Complete recovery 20%.
De Fine M, et al. (2017). Sciatic Nerve Palsy following Total Hip Replacement. BioMed Research International. PMID 29270435. Systematic review, 14 studies. No hazardous lengthening threshold identifiable. Sciatic palsies are over 90% of neurologic injuries after hip replacement.
Eggli S, et al. (1999). Nerve palsy after leg lengthening in total replacement arthroplasty for developmental dysplasia of the hip. J Bone Joint Surg Br. PMID 10530847. 508 dysplastic hips. Lengthening amount not correlated (p=0.47); operative difficulty correlated (p=0.041).
Kayani B, et al. (2026). The Management of Neurological Injuries Following Total Hip Arthroplasty. J Bone Joint Surg Am. PMID 41452940. Current-concepts review. Nerve testing at 3 to 6 weeks; physical therapy, brace and neuropathic pain treatment as the non-surgical mainstay.
Slaven SE, et al. (2023). Motor Nerve Palsy After Direct Anterior Versus Posterior Total Hip Arthroplasty. J Arthroplasty. PMID 37019317. 10,047 hip replacements. Approach shifts which nerve is injured.
Coden GS, et al. (2024). Similar incidence of postoperative sciatic nerve palsy in direct anterior and posterior approach total hip arthroplasty. Hip International. PMID 38654687. 17 sciatic palsies across 12,899 hip replacements. No approach difference (p=0.5).
Su EP (2017). Post-operative neuropathy after total hip arthroplasty. Bone Joint J. PMID 28042118. 39,056 hip replacements, incidence 0.3%. Imaging mandatory on diagnosis.
Edwards BN, et al. (1987). Contributory factors and etiology of sciatic nerve palsy in total hip arthroplasty. Clin Orthop Relat Res. PMID 3568473. The origin of the lengthening-dose idea. Nerve testing localised stretch palsies to the outside of the knee.
Georgeanu VA, et al. (2022). Common peroneal nerve palsy after primary total hip arthroplasty. International Orthopaedics. PMID 35711003. 6 palsies in 1,240 hip replacements. Authors report no consensus regarding treatment.

Educational information, not personalized medical advice. If you have new weakness after hip replacement surgery, contact your surgical team.

A hip replacement can stretch the nerve that lifts your foot.