Limb Length Discrepancy: Causes, Symptoms,
Complications, and Treatment Options
What is Limb Length Alignment/ Discrepancies?
This condition can be congenital and is characterized by a noticeable difference in the length of one arm or leg. Differences in arm length are less likely to disrupt daily functioning compared to leg length discrepancies, which can significantly affect a child’s quality of life. Variations in limb length can range from less than an inch to several inches, impacting a person’s ability to walk, stand, or maintain balance.
Types of Limb Length Alignment/Discrepancies
Limb length discrepancy (LLD) can be further categorised as static or progressive deformity:
1. Static
This type of LLD refers to a discrepancy that remains constant, often due to a malunion of a fracture in the lower limbs. Malunion occurs when a fractured bone heals in an abnormal position.
2. Progressive
This type of LLD refers to a discrepancy that worsens over time as the child grows. It could be due to an injury to the growth plate or a condition present at birth.
Causes of Limb Length Alignment/Discrepancies
Discrepancies in limb length can result from congenital problems or conditions that affect hip alignment, such as developmental dysplasia of the hip (DDH). Other causes include:
- Bone injuries
- Bone infections
- Bone tumours
- Neuromuscular conditions
Signs and Symptoms of Limb Length Alignment/Discrepancies
The signs and symptoms of limb length discrepancy vary based on the extent of leg length differences. Some common signs and symptoms include:
- Walking difficulties, such as limping or tiptoeing on the shorter leg
- Abnormal posture, such as shoulder tilting
- Pain in the ankles, knees, hip, or back
- Difference in bone size
- Fatigue due to increased effort in movement
What Are Some Complications?
If left untreated, leg length discrepancy can lead to:
- Back pain
- Pain from osteoarthritis
- Functional scoliosis
- Joint problems
Treatment Options
The treatment for limb length discrepancy varies based on the cause, severity, and the child’s age. For minor discrepancies, correction can often be achieved with a shoe lift or insert. However, if there are significant differences in leg length, surgery may be recommended to prevent further complications. Some surgical procedures include:
1. Epiphysiodesis
This procedure aims to slow or stop the growth in the longer leg by making small incisions around the knee, allowing the shorter limb to catch up. It is typically recommended for children who are still growing.
2. Limb shortening
This procedure is recommended for patients with smaller leg discrepancies. During the procedure, a segment of bone from the middle of the longer limb is removed, and a metal rod or plate is placed to hold the bone while it heals.
3. Limb lengthening
This procedure is usually recommended for patients with larger leg discrepancies and can be performed either externally or internally.
4. External lengthening
This involves cutting the bone in the shorter leg and inserting a frame to hold the bone in place with pins or wires as it heals.
5. Internal lengthening
Similar to external lengthening, this involves cutting the bone in the shorter leg. However, instead of using a frame, a metal rod is surgically implanted and gradually lengthened to pull the bones apart, allowing new bone to grow in its place.