Paralympian swimmer Jessica Long was born with bilateral fibular hemimelia, a congenital shortening or absence of the fibula.
If you watched any of the Tokyo Olympics, you were no doubt moved by a commercial from Toyota that featured Long, depicting a phone call to her parents about a baby they are going to adopt from a Siberian orphanage.
Despite the fact that they are told she has a rare condition that will require she have both legs amputated, her mother is delighted to have her. “It might not be easy, it’ll be amazing … and I can’t wait to meet her,” she says. Long joined her American family in Baltimore at the age of 13 months.
At 18 months, she underwent bilateral lower leg amputations and learned to walk with prostheses. Unfortunately, as she grew, she needed to undergo 25 additional surgical procedures. However, this didn’t slow her down, and she was active in many sports, including gymnastics, cheerleading, ice skating, and rock climbing.
She began swimming in her grandparents’ pool as a small child. Removing her heavy prostheses, she would crawl on her knees to the pool edge and jump in. In a “Today” show interview with Kathy Park, Long said, “I just instantly loved it. For me, water has always been a place of freedom, safety, but also of feeling really strong and capable.”
She made her Paralympics debut at the age of 12 in the 2004 Athens, Greece games. As the youngest competitor on the U.S. Paralympic team, she won three gold medals. At the age of 29, Long is competing in her fifth Paralympic games in Tokyo, where so far she has won one gold medal, two silver, and one bronze. “I’m so grateful that my body still works the way I want it to, and I’m doing a sport I love,” she said.
What Is Fibular Hemimelia?
Fibular hemimelia is a congenital longitudinal limb deficiency characterized by complete or partial absence of the fibula bone, with an estimated incidence between 7.4 and 20 per 1 million live births. A slight male preponderance has been reported in some studies, whereas other reports describe an equal sex distribution.
Two-thirds of cases involve only one limb, with the right fibula being affected more often than the left. Agenesis (complete absence) of both fibulae is rare. Fibular hemimelia may vary from partial absence of the fibula (10% of cases) with relatively normal-appearing limbs, to absence of the fibula with marked shortening of the femur, curved tibia, bowing of the leg, knee joint and ankle instability, and significant soft tissue deficiency.
The etiology is unclear. The deformity is probably due to disruptions during the critical period of embryonic limb development, between the fourth and seventh week of gestation. Vascular dysgenesis, viral infections, trauma, and environmental influences have been suggested as possible causes.
Most cases are sporadic. A family history has been reported in a small percentage of cases, with an autosomal dominant pattern of inheritance and incomplete penetrance.
The major functional deficiency results from leg length discrepancy in unilateral cases or asymmetrical dwarfism in bilateral cases. Other lower limb abnormalities are often present. For example, the foot is often in an equinovalgus position (“equino” means plantarflexed, as in standing on one’s toes, and “valgus” means that the base of the heel is rotated away from the midline of the foot). Other abnormalities include femoral hypoplasia with external rotation, hypoplastic lateral femoral condyle, knock knees, absent tarsal bones, tarsal coalitions, absent foot rays, and ankle valgus (pronation of the foot and medial malleolar prominence). This complex of abnormalities has led some to suggest that the term “proximal hypoplasia of the lower extremity” is a more accurate term for the disorder.
Aside from the original leg length discrepancy, the growing potential within the affected bone is limited. In addition, the extent of the deformity tends to increase with growth. Other skeletal anomalies (craniosynostosis, syndactyly, brachydactyly, oligodactyly, and ectrodactyly) may also be present. Fibular hemimelia is also found in several generalized skeletal dysplasias and dysostoses. Rarely, fibular hemimelia is associated with non-skeletal malformations (eye abnormalities such as anterior chamber anomalies or anophthalmia, cardiac anomalies, renal dysplasia, thrombocytopenia, thoracoabdominal schisis, spina bifida, and, rarely, intellectual deficit). Fibular hemimelia can be present in some chromosome anomalies.
Treatment of Fibular Hemimelia
The ultimate goal of treatment is to enable a child to gain maximum function by achieving lower leg alignment, length, and stability. The choice of treatment is based on several different factors:
- The amount of bone missing
- The difference in leg lengths
- How growth may affect the problem
- Whether there are other foot, ankle, or leg problems
Treatment is primarily surgical, although those with very mild disease (difference <2 cm) may not require any treatment or may be helped with a heel lift. Even these individuals need to be followed until skeletal maturity, as growth may increase leg length discrepancies.
Epiphysiodesis is a surgery that is performed on the physis, or growth plate, of the longer leg. The surgery can involve drilling the growth plate, placing screws across it, or tethering it on either side with plates to prevent the bone from growing.
Another option is limb-lengthening surgery. “Limb lengthening is achieved using the body’s own capacity to regenerate new bone as well as the soft tissues, ligaments, blood vessels, and nerves that surround and support it. The process begins with an operation called an osteotomy, in which the orthopedic surgeon cuts the bone to be lengthened. The limb is then stabilized using one of several different external and/or internal fixation devices or frames,” explained S. Robert Rozbruch, MD, of the Hospital for Special Surgery in New York City.
There are two phases of recovery from limb-lengthening surgery. In the first, called the distraction phase, the cut bone is very gradually pulled apart, typically one-quarter of a mm 4 times a day. The body grows new bone and tissue in the increasing space until the desired amount of bone is attained. The maximum amount of length that can be added with this method is about 8 inches (20 cm). Patients walk with crutches during this phase.
In the second phase, the patient gradually puts more weight on the affected limb, as the bone consolidates and heals.
It is generally agreed that patients with a discrepancy of less than 10% can benefit from lengthening procedures with epiphysiodesis on the contralateral leg.
Other surgical procedures may be required to repair other bones, muscles, tendons, and joints that did not form correctly.
For those with severe deformities, amputation followed by the use of prostheses may be the preferred method of treatment. Patients in this category include those with a nonfunctional foot and those with a leg length discrepancy greater than 30%. A variety of new prosthetics allow children to participate in many activities, including running, jumping, and climbing. These patients will need to see an orthotist once a year to adjust their prostheses as they grow.
Michele R. Berman, MD, is a pediatrician-turned-medical journalist. She trained at Johns Hopkins, Washington University in St. Louis, and St. Louis Children’s Hospital. Her mission is both journalistic and educational: to report on common diseases affecting uncommon people and summarize the evidence-based medicine behind the headlines.
Source: MedicalNewsToday.com
