A Child with a Limp
by Dr. Vinaya Kunjir

When a child limps, it is a major cause of worry and anxiety for the parents. A child's pain disturbs the child as well as the functioning of the whole family.

A limp is defined as any change in walking pattern or gait which is different from the expected normal pattern of walking for the Child's age.

A child begins to walk at the age of 12-14 months but gets the mature adult walking pattern at approximately 3 yrs of age. Limping can be due to different causes -

Some are mild temporary but some may be severe, causing permanent disability. Limping can be caused by three processes -

1.Pain: limp may be due to pain in bone, joint or soft tissues.
The child will try to bear minimum weight on the painful leg and will try to carry his weight on the healthy side.

2.Structural abnormalities: Limp can be caused due to abnormalities or deformities in the structure of the legs - for example leg-length discrepancies, muscle contractures or shortened tendons of the legs, angular deformities of the limbs. They may be congenital (since birth) or may be acquired later in life.

3.Neuromuscular problems: unsteady gait can be a result of any injury or lesion affecting the brain, causing loss of control over the muscles or movement of limbs.

In this article I will not be dealing with the structural or neuromuscular causes of limping.
The different causes of limp in children of all ages are

1.Trauma: Joint swelling associated with trauma is seen in school going children and adolescents. A minor trauma brings a swollen joint to parental attention. Trauma can cause bleeding into the joint leading to swelling of joints, Fracture or even joint derangement. Surgical treatment may be needed sometimes.

2.Septic Arthritis: It is the most concerning cause of limp as it causes joint destruction. The severe pain of septic arthritis results in the child's refusal to walk or even move the joint. The child appears very sick and the joint becomes swollen, warm and very painful. It is a surgical emergency and needs immediate treatment. Joint aspiration and immediate Antibiotics can lead to complete recovery of the child.

3.Osteomyelitis: it is an infection inside the bone with bacteria or sometimes fungi. May result from trauma such as fracture or puncture wound. If untreated it leads to necrosis and destruction of the bone.

The child refuses to bear weight on the affected side or even move the joint.

4.Stress Fracture or Overuse syndrome: they are secondary to repetitive microtrauma. Usually seen in children who begin activity after long periods of inactivity or after beginning of sporting activity. Stress fractures are seen in long bones of arms, forearms, thigh and shin. Sometimes injury or fractures are seen in soft tissues or muscle insertion like Osgood Schlatter's disease(injury to tibial tubercle, below the knee), Sever disease (Injury to insertion of tendoachilles muscle) or in the foot bones. These fractures/ injuries cannot be seen in plain Xrays but need bone scan or MRI scan for diagnosis.

5.Neuromuscular causes: limping caused by muscle weakness due to neurological damage/ injury.

6.Neoplasm/ bone tumours: Bone tumour is suspected if the child complains of persistent pain associated with weight loss, fatigue, waking from sleep with pain, night sweats.

Tumours can be benign (good prognosis) or malignant (spreading tumours with bad prognosis)
Benign tumours – bone cysts, aneurismal bone cysts, fibrous dysplasia, eosinophilic granuloma. Malignant bone tumours – Ewing's sarcoma, osteogenic sarcoma. Usually occur in long bones of thigh, arm and shin.

Leukemia – cause painful limp in children. Mostly seen in large joints like knees. Pain is severe in leukemia. Tumours are usually located near the shaft of long bones rather than on joint itself.

7.Juvenile Idiopathic Arthritis: (JIA) Also called as chronic arthritis in childhood and is one of the most common rheumatic diseases of childhood. JIA is defined as arthritis of unknown cause, occuring before the child's 16th birthday and lasting for more than 6 weeks. JIA is also important cause of short and long term disability in children.

JIA is also divided into several subcategories depending on the modes of presentation of arthritis – oligo arthritis (less than 4 joints involved), poly arthritis (more than 4 joints involved) and systemic JIA (arthritis associated with systemic features of fever, skin rash and organ involvement)

There are few causes of limp which are different for different age-groups.

They are –

A. Toddler - (1 - 3 years old)

1.Toddler's fracture – bones of young children are brittle. Minor trauma such as jumping or twisting can cause incomplete fracture usually in bones of legs and feet.

2.JIA – Knees, ankles, feet and hip joints can be involved in oligo arthritis or poly arthritis JIA. Localised destruction of the joints or growth abnormalities as seen in severe poly arthritis. JIA can cause permanent limp and disability in child. Longterm treatment with Disease-modifying antirheumatic Drugs and physical therapy is required.

3.Transient Synovitis of the hips – seen in very young children. The pain may be very severe but lasts no more than 1 to 2 weeks. Symptomatic treatment is needed. No specific treatment required.

4.Septic arthritis - it is a surgical emergency. The child refuses to walk or even move his leg. Usually seen in knees, hip joints.

5.Leg-length discrepancy - causes limp in a child. It is important to establish the cause of leg length discrepancy as some of the causes can be progressive. Generally less than 2 cm of inequality is acceptable in adult leg-length. If it exceeds this, then orthopaedic management is required.

B. Child - (4 - 10 years old)

1.Transient synovitis of hip- self limiting disease. No specific treatment is required.

2.Juvenile Idiopathic Arthritis

3.Leg-Calve-Perthe's Disease – usually seen in males of age 4 - 8 years old. Limp starts slowly and the child complains of pain in hip, groin or knee. There is decrease in the blood supply to the femoral head of the hip joint which causes slow destruction of the femoral head. In severe cases, surgical intervention is needed.

C. Adolescent – (11 - 16 years of age)

1.Slipped capital femoral epiphysis – (SCFE) usually seen in overweight adolescent children prior to growth spurt. Sometimes seen in hypothyroidism. Pain is in groin, hip, knee joint. The patient should take rest and should not bear weight as there is a risk of further slipping of epiphysis and decrease in blood supply to the femoral head. Severe cases need surgical intervention.

2.Chondromalacia – also known as patellofemoral pain syndrome. The child limps and has pain in knees, which is worse with activity of knee bending and stair climbing. It is caused due to weakness in thigh muscles as a result of repetitive micro-trauma in muscles. Child improves with rest and quadriceps strengthening exercises.

3.Avascular necrosis of femoral head- The limp begins slowly and the child has pain in groin and hip region. It is caused by decrease in blood supply to femoral head. Severe cases need surgical intervention.

4.JIA

5.Bone tumours / neoplasm.

Management of children with a limp requires a multi-disciplinary team of health professionals (paediatrician, paediatric rheumatologist, paediatric orthopedician, physiotherapist) for diagnosis and care. Improved application of old techniques and development of new approaches have been important contributors for improved prognosis.

References :-

1.Textbook of pediatric rheumatology by J.Cassidy et.al (Fifth edition)