Types of limb-length discrepancies
- Structural limb-length discrepancy
This occurs when one bone in an arm or leg is shorter than its corresponding bone in the other limb.
- Functional limb-length discrepancy
In this case, the bones in both arms or legs are of equal length, but a joint contracture, such as limited mobility in a knee, hip, elbow, or other joints, causes asymmetry.
Symptoms of limb-length discrepancies
Leg-length discrepancies have a more significant impact on children and may require treatment. The symptoms of this condition can vary from child to child and may include the following:
- Uneven lengths of the thigh bone (femur) and shin bone (tibia), with the possibility of the smaller lower leg bone (fibula) being affected as well.
- Difficulty walking, such as limping, waddling, or walking on the toes of the shorter leg.
- Increased fatigue due to the extra effort required to move.
- An increased risk of other related conditions, including low-back pain, osteoarthritis, and scoliosis.
When limb-length discrepancies affect legs, the symptoms are more noticeable, and treatment is often needed.
Causes of limb-length discrepancies
A variety of factors can cause limb-length discrepancies, including:
- Bone diseases or dysplasias include Ollier disease, neurofibromatosis, and multiple hereditary exostoses.
- Bone infections disrupt growth plate development.
- Neurological conditions, such as cerebral palsy, spasticity, and paralytic disorders.
- Inflammatory joint conditions, such as juvenile idiopathic arthritis.
- Trauma or injury to a bone that leads to healing in a shortened position or faster growth on one side, particularly in the case of compound fractures near or in the growth plates.
- Congenital conditions, such as clubfoot, developmental dysplasia of the hip, hemihyperplasia, and proximal femoral focal deficiency, impact growth on one side of the body or in a specific bone.
- Tumors or tumor removal surgery can temporarily or permanently affect nearby growth.
In many cases, these causes are present at birth, but the limb-length discrepancy may not be noticeable until later in childhood. In some cases, the cause remains unknown.