Limb Length Discrepancy
Many people have arms or legs of different lengths, but the discrepancy is often so slight that it presents no problems. The greater the difference, however, the more likely that it will cause pain or interfere with activities.
Yale Medicine Orthopaedics & Rehabilitation offers a range of treatment options for limb length discrepancy for both pediatric and adult patients.
“It’s very common for people to have small differences in length that they never notice,” says David Frumberg, MD, a Yale Medicine specialist in treating orthopaedic conditions that include limb length differences. “Treatment can be considered if the difference becomes significant enough.”
What is limb length discrepancy?
Limb length discrepancies are simply differences in size between the length of both arms or both legs—and it can occur in the upper and lower portions of each. The difference in length can range from a fraction of an inch to several inches.
What causes limb length discrepancy?
Causes of limb length discrepancy usually fall into one of three categories:
- Congenital. A person may be born with an underlying skeletal condition that affects the development of bones, so the difference is present at birth and often becomes more apparent as a child grows. Some types of bone dysplasia (abnormal bone tissue) can also lead to length differences.
- Fracture. An injury to a growing bone can result in a limb length difference. Fractures that involve a growth center can cause abnormal growth. Some types of fractures can otherwise lead a bone to grow too long—most commonly seen in fractures of the femur (thigh bone).
- Infection or tumor. The presence of a bone infection or a bone tumor in a child’s growing skeleton can interfere with the growth of a limb. It may stop or slow down relative to the other arm or leg.
How is limb length discrepancy diagnosed and treated?
Medical history, physical examination, and imaging studies are used to evaluate the cause and extent of a patient’s limb length discrepancy.
There are several treatment options, each of which depends on age, remaining growth (for children), the extent of the discrepancy, the associated bone deformity, as well as the goals and preferences of the patient and their family.
One option—the easiest, least-invasive, and sometimes sufficient for a small leg discrepancy—is to wear a lift in the shoe for the shorter leg.
For a more permanent solution, surgical procedures are available:
- Epiphysiodesis, which closes the growth plate of the longer leg, so the shorter leg can match it. Typically done a few years before a child is finished growing, this is considered an easy procedure that is effective for mild differences in length. The procedure halts growth by fusing the growth plate.
- Lengthening bone in the shorter leg or arm, so it will match the longer one. This surgery involves cutting the bone in a special way and slowly lengthening it. This may be done with an external device that connects to the bone through the skin—or, a motorized rod that goes inside the bone can be used. This technology uses a control device outside the skin to gradually extend the length of the bone, typically 0.75 to 1 millimeters per day.
How can limb-lengthening be achieved using internal lengthening nails?
An internal motorized lengthening nail consists of a telescopic rod (containing a motor or gears) that is surgically implanted in the short bone. In some cases, this can be done as an outpatient surgery, but it typically involves a single overnight stay in the hospital. A remote control device is then held up to the skin several times a day and used to expand the implanted rod. This lengthening is usually painless. It's important to note that ongoing physical therapy is required to help the muscles and tendons adapt to the changes.
This technology is primarily used to lengthen long bones—the tibia and femur in the leg, and the humerus bone in the upper arm. The nail can also be used in patients with limb loss, in an effort to improve the patient’s ability to use a prosthesis. Other uses include filling bone defects after tumors or trauma.
What makes Yale Medicine's approach to treating limb length discrepancy unique?
The Yale Limb Restoration and Lengthening Program takes a multidisciplinary approach to both simple and complex limb problems. The combination of orthopaedic surgery, plastic reconstructive surgery, vascular surgery, physical therapy, and other specialists ensures each person gets the best treatment for their limb differences. In many cases, patient-specific customized treatments are designed through Yale’s 3D surgical innovations program.
Known for innovation and excellence in musculoskeletal care, Yale was among the first Connecticut hospitals to offer limb-lengthening using internal lengthening nail technology. This also includes individuals seeking height surgery—limb-lengthening for cosmetic purposes.
“My patients get innovative care with the most advanced techniques at Yale Medicine,” Dr. Frumberg says. “An entire team of specialists is needed for successful limb-lengthening surgeries. This includes physical therapists, nurses, and pain management experts. We also have world-class specialists in physiatry, psychology, and bone endocrinology, all of whom work diligently to ensure someone opting for limb-lengthening surgery has the best result.”