New Surgery Technique May Correct Severe Bowed Legs in XLH Patients, Case Study Shows

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by Marta Figueiredo |

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A new technique of osteotomy — a surgery in which bone is cut to allow repositioning — may be an effective approach to correct severe bowed legs in people with X-linked hypophosphatemia (XLH), a case report suggests.

The report also highlighted the importance of early XLH diagnosis to prevent the progression of bone deformities and the need for multiple corrective surgeries.

The case study, “Rotational and translational osteotomy for treatment of severe deformity in hypophosphatemic rickets: A case report,” was published in the journal Medicine.

XLH is characterized by low blood levels of phosphorus (hypophosphatemia), an important bone component. Among other manifestations, people with this disorder may show delayed growth, short stature, rickets, osteomalacia — softer and weaker bones more prone to fracture —, and bone deformities such as bowing of the legs, bone-related pain, and dental problems.

Surgery is often necessary to correct severe bone defects in XLH patients, with osteotomy being frequently used to fix bowed legs.

In the study, researchers in China reported the successful use of a new osteotomy technique to correct severe outward bowed legs, or genu varum, in a 11-year-old boy with delayed XLH diagnosis.

The patient was admitted to the Wuhan Union Hospital due to persistent pain in his left thigh after a fall. A radiography revealed a small fracture in his left femur (the long bone in the upper leg).

He was short in stature (1.1 meters or 3.6 feet) for his age, with severe bowing of both femurs, which was associated with walking difficulties and previous multiple falls resulting in three femoral fractures. He had also undergone corrective surgery on his left femur, but it was ineffective.

The boy’s mother and sister had obvious genu varum and hyperextension of the knee joint. His mother was also short, at 1.2 meters (3.9 feet) tall.

Blood tests showed hypophosphatemia, high levels of the liver enzyme alkaline phosphatase (which can indicate liver or bone problems), and normal calcium levels.

Based on the boy’s clinical data and family history, he was diagnosed with left femoral fracture linked to XLH with genu varum.

After discussing the best method to correct the boy’s bone deformities, the team decided to use a new technique called rotational and translational osteotomy, followed by fixation with a proximal humerus internal locking system plate.

“This technique was derived from the procedures utilized in the correction of scoliosis [a sideways curve of the spine],” the researchers wrote.

The surgery was performed first on the left femur and six months later on the right femur, with additional procedures on both shinbones (the larger bone in the lower leg). At follow-up, the sites where the femur was broken had healed well, and the boy resumed daily activities and normal sports. At the latest visit (more than two years after the second surgery), the boy showed normal balance, and he was able to stand, walk, and sit almost normally.

Although he had a slight bone deviation to the lateral side of the left knee joint, the boy was quite satisfied with the result, the team said.

“In summary, rotational and translational osteotomy is an alternative technique” for patients with severe bowing deformity, the researchers wrote.

Raising awareness of XLH among the medical community is important to allow early diagnosis and prevent the progression of bone problems and multiple surgical interventions, the team added.