23.3 LIMPING CHILD
TABLE 23.6: Causes of leg-length discrepancy
Human gait is cyclic, with two dynamic phases: (a) stance phase, when one of the two feet is on ground; and (b) swing phase, when legs are advancing forward but with no ground contact.
Development of gait is a function of orthopedic stability and neuromuscular maturation. Early childhood gait is physiologically wide-based, which matures gradually with achievement of normal adult gait by seven years.
Limping is a common gait abnormality in children due to orthopedic or neuromuscular causes (Table 23.5), which may be broadly divided into 3 groups:
a. Painful Antalgic gait with 'shorter stance' phase on affected side to avoid ground contact with painful limb, usually due to acute inflammatory orthopedic disorders.
b. Painless Trendelenburg gait with 'normal stance' phase but a tilt towards the affected site, usually due to neuromuscular disorders (hemiplegic gait) or developmental orthopaedic disorders.
c. Waddling gait, due to bilateral disorders, which may be painful or painless.
Evaluation of limp depends on the suspected pathology after physical and neuromuscular examination, although MRI (to visualize unossified joints) and muscle enzymes studies (for myopathies) are useful in cases without obvious etiology.
Some important orthopedic causes of limping or gait abnormalities are as follows:
Leg-length discrepancy may be congenital or acquired, due to orthopedic or neuromuscular disorders in growing child (Table 23.6). Clinically, leg length should be measured from anterior superior iliac spine to medial malleolus, though roentogenographic measurements
TABLE 23.5: Common causes of limping child
Painful limp (Antalgic gait)
• Infections: Osteomyelitis, septic arthritis
• Rheumatic: Rheumatoid arthritis, transient hip synovitis
• Trauma: local sprains, dislocations and fractures
• Neoplastic: Bone cysts/tumors, leukemia
• Congenital: Tarsal coalition
• Osteochondroses: *LCPD, SCFE
• Painful foot: skin problems, un-fit shoes
Painless limp (Trendelenburg gait)
• Neuromuscular disorders
- Central : Cerebral palsy
- Spinal : Poliomyelitis
- Myopathies : Duchenne muscular dystrophy
• Developmental orthopedic disorders
- Developmental dysplasia of hip
- Leg-length discrepancy
*See Ch. 23.6
Congenital
• Developmental dysplasia of hip (DDH/CDH)
• HerneatrophyAhypertrophy of limbs
Acquired
• Post-infective: Osteomyelitis, arthritis
• Post-traumatic malunion or overgrowth
• Osteochondrosis: Legg-Calve-Perthes disease
• Neuromuscular: Cerebral palsy, poliomyelitis
• Others: Limb tumors, surgery, etc.
are more reliable. While mild limb-length discrepancy is common and asymptomatic, severe cases with gt;2 cm difference or associated limp (Trendelenburg gait) require intervention with orthotic/prosthetic support and/or surgical correction (if gt;5 cm) with limb shortening or lengthening procedures.
Equinus gait (Persistent toe-walking) is uncommon but important indicator of underlying neuromuscular disorders, e.g. cerebral palsy or tendo-Achilles contractures. Toe-walking is normal till 3 years of age and some children toe-walk habitually.
In-toe/out-toe walking is a common cause of parental concern, though most of these abnormalities improve with age and no treatment is needed except parental assurance.
• In-toe walking is usually caused by developmental torsion defects, e.g. internal femoral torsion (gt;2 years), internal tibial torsion (lt;2 years), or congenital talipes equinovarus.
• Out-toe walking is usually caused by external tibial version, external femoral version, or congenital talipes equinovalgus.
23.4