Limping: Causes and When to Worry

What causes a limp

A limp has three basic causes:

1. Pain (antalgic gait): you spend less time on the painful leg, so steps are short and uneven. This is the most common type.
2. Weakness or nerve problems: for example a foot that slaps or drags (foot drop), or a hip that dips on each step.
3. Structural problems: unequal leg length, a stiff joint or a deformity.

Pinpointing where the problem is (foot, ankle, knee, hip, back) is the first step. Hip problems, especially in children, often cause pain felt in the thigh or knee instead of the hip.

Common causes in adults

Injuries

Ankle sprains, muscle strains, bruises, fractures and stress fractures of the foot or shin are common reasons for a sudden limp.

Arthritis

Osteoarthritis of the hip or knee causes a gradually worsening limp, stiffness after rest, and pain on walking. Gout causes a sudden, hot, swollen joint, often the big toe.

Foot and heel problems

Plantar fasciitis, corns, ingrown toenails, bunions, Achilles tendon problems and Morton's neuroma all cause pain with each step.

Back and nerve problems

Sciatica causes leg pain and sometimes weakness. A trapped nerve in the lower back can cause foot drop. Spinal stenosis causes leg pain on walking that eases with sitting.

Circulation

Peripheral artery disease causes cramping calf pain after walking a set distance, which eases with rest.

Neurological conditions

Stroke, multiple sclerosis, Parkinson's disease and peripheral neuropathy change gait through weakness, stiffness or poor balance.

Causes of limping in children

By age

Transient synovitis

The most common cause of a hip limp in children aged 3 to 10. Temporary inflammation of the hip joint, often after a cold, causes hip or knee pain and a limp. The child is usually well, with no or low fever. It settles within 1 to 2 weeks with rest and pain relief.

Septic arthritis and osteomyelitis

Bacterial infection in a joint (septic arthritis) or bone (osteomyelitis) causes fever, severe pain and refusing to bear weight. Septic arthritis can destroy a joint within days and needs emergency treatment. Doctors distinguish it from transient synovitis using fever, blood tests and ultrasound.

Toddler's fracture

A twisting fall can cause a hairline fracture of the shin bone. The toddler refuses to walk or limps, sometimes after a fall nobody saw. The first X-ray may look normal.

Perthes disease

Interruption of blood supply to the ball of the hip, usually in boys aged 4 to 8, causing a limp and mild hip or knee pain over weeks.

Slipped capital femoral epiphysis (SCFE)

The ball of the hip slips off the thigh bone at the growth plate, usually in overweight children aged 10 to 16. It causes hip, thigh or knee pain and a limp with the foot turned outward. It needs urgent surgery to prevent further slipping.

Developmental dysplasia of the hip

A shallow hip socket present from birth. A painless limp when a child starts walking can be the first sign. See hip dysplasia.

Other causes in children

Juvenile arthritis (morning stiffness and swollen joints), leukemia (bone pain, bruising, pallor, fevers), and bone tumors (night pain, a lump) are less common.

Limping without pain

A painless limp can come from leg length difference, a hip problem present from birth, muscle weakness, nerve conditions, cerebral palsy, muscular dystrophy, or a previous injury that changed how you walk. It still deserves assessment, especially in a child.

How a limp is assessed

A clinician will ask when it started, about injuries, fever, pain location, night pain, morning stiffness and weight loss. They watch you walk, examine the spine, hips, knees, ankles and feet, check joint movement, strength, reflexes, leg length and pulses. Tests may include:

• X-rays: including both hips in children with knee pain, since hip problems can refer pain to the knee
• Ultrasound of the hip to look for fluid
• Blood tests: white cell count, CRP and ESR for infection or inflammation; blood count for leukemia
• Joint aspiration if infection is suspected
• MRI for early stress fractures, Perthes disease, infection or nerve compression

Treatment

Treatment depends on the cause:

• Minor injuries: rest, ice, compression, elevation, then gradual return to activity.
• Pain relief: acetaminophen (paracetamol) or ibuprofen at the label dose. Do not give aspirin to children or teenagers.
• Infection: antibiotics, often IV, and surgical washout of an infected joint.
• Fractures: casts, boots or surgery.
• SCFE: surgery to fix the hip with a screw.
• Arthritis: exercise, physical therapy, weight management, anti-inflammatories and joint injections or replacement for severe osteoarthritis.
• Gait problems: physical therapy, orthotics, shoe lifts for leg length difference, braces for foot drop, and walking aids.

Frequently asked questions

What causes a sudden limp in a child with no injury?

The most common cause is transient synovitis, a short-lived hip inflammation that often follows a cold. A toddler's fracture can also happen without an injury anyone noticed. Because infection must be ruled out, a child who has a fever, looks unwell or will not bear weight needs same-day assessment.

When should I worry about a limp?

Worry if the limp comes with fever, severe pain, refusal to walk, a hot or swollen joint, night pain, weight loss, numbness or weakness, or if it follows a fall in an older adult. Any limp that is not improving after a week should be checked.

Can back problems cause a limp?

Yes. A trapped nerve in the lower back can cause leg pain (sciatica) or weakness, such as foot drop, that changes how you walk. Spinal stenosis can cause leg pain and heaviness on walking that make you limp. Weakness or numbness needs prompt assessment.

Why does my child limp but has no pain?

A painless limp can be due to a hip problem present from birth, a leg length difference, muscle weakness or a nerve or muscle condition. Some children have mild pain they cannot describe. A doctor should examine any persistent limp, even without pain.

How long does a limp from transient synovitis last?

Most children improve within a few days and recover fully within 1 to 2 weeks. Rest and pain relief are usually enough. If the limp lasts longer, comes back, or fever develops, the child should be re-examined to rule out infection or Perthes disease.