What is Adult Leg Length Discrepancy?
Adult leg length discrepancy is a condition in which an individual’s legs are of unequal length with one leg shorter than the other. This can occur as a result of fractures or bone diseases.
The difference in leg length may range from a fraction of an inch to multiple inches. If the difference in leg length is visibly greater, it can result in an abnormal body posture and walking pattern. This can trigger a variety of symptoms, including functional scoliosis, as well as problems with the knees, hips, and ankles. The femur (thighbone) and tibia (shinbone) are the 2 bones most commonly affected with adult leg length discrepancy.
Causes of Adult Leg Length Discrepancy
Fractures are the most common causes of adult leg length discrepancy. A broken leg bone can lead to limb length discrepancy if it fails to heal properly (nonunion) or heals in a shortened or overlapped position (malunion). Normally, these cases occur in adult patients if the bone has sustained multiple fractures or has shattered into several fragments as in a comminuted fracture. It is also more likely to occur if the muscle and skin tissue around the bone is acutely damaged and exposed as in an open fracture.
- Comminuted fracture: A severe type of fracture where the leg bone breaks into 3 or more pieces as in a high-energy motor vehicle accident
- Open fracture: This is also known as a compound fracture and causes serious damage to the surrounding soft tissue structures as the bone fragments to protrude out through the skin to the external air exposing the fracture site.
Bone diseases such as multiple hereditary exostoses and neurofibromatosis can also cause adult leg length discrepancy.
Signs and Symptoms of Adult Leg Length Discrepancy
Some of the common signs and symptoms of adult leg length discrepancy include:
- Problems walking, such as toe-walking, limping, or a waddling gait.
- Postural problems, such as an uneven or tilting shoulder.
- Pain in the knees, hips, back, or ankles.
- One leg is visibly shorter than the other leg.
Diagnosis of Adult Leg Length Discrepancy
In order to diagnose adult leg length discrepancy, your physician may perform the following:
- Examination to analyze your gait pattern and measure the leg length discrepancy.
- X-rays to obtain a precise measurement of the bone length discrepancy.
- A special type of X-ray called a scanogram may be ordered for more precise measurements of the discrepancy than normal x-rays can provide.
- Computerized tomography (CT) scans for detailed images of the bones and soft tissue structures of the legs not visible on X-rays.
Treatment for Adult Leg Length Discrepancy
The mode of treatment depends upon the severity of the discrepancy and the general health and age of the patient.
If the leg length discrepancy is less than 2 cm, your physician may recommend the placement of a shoe lift inside or outside of the shoe to correct the discrepancy and help improve your ability to walk and run.
Surgical intervention is recommended for a leg length discrepancy of more than 2 cm and is designed to achieve either shortening of the longer leg or lengthening of the shorter leg.
- Limb shortening surgery: During this surgery, your surgeon removes a section of the bone from the middle of the longer leg and then places a rod or metal plates and screws to reattach and hold the bone ends in position while it heals.
- Limb lengthening surgery: This is the most commonly employed method of treatment in which the shorter leg is lengthened using either an external fixator device such as a Hexapod frame on the outside of the leg or a device such as a PRECICE nail that is placed inside of the leg.
- The PRECICE nail implant is the most recent and state-of-the-art limb lengthening device that is inserted into the intramedullary canal or center of the affected leg bone. It utilizes a magnetically controlled intramedullary lengthening nail that enables controlled lengthening of the long bones without the need for external wires or pins.
Adult leg length discrepancies are quite common. In fact, most adults have some minor degree of leg length discrepancy. However, larger differences of more than 2 cm can adversely affect your general well-being and quality of life. With proper treatment, adults with leg length differences can look forward to a normal and active lifestyle without any cosmetic or functional deficiencies.