Simultaneous knock knees correction and thigh lengthening in a 9-year-old girl with Ollier’s disease (enchondromatosis)

With a prevalence of 1/100000 cases, enchondromatosis is a rare bone disease which can cause severe deformities due to partially pronounced tumorous lesions, especially of the long tubular bones. If the affected bone is limited to one side of the body only, the condition is called Ollier’s disease.

This case study is of a 9-year-old girl with Ollier’s disease. In the following text, we describe a surgical correction of a 30-degree bow-leg malposition and leg length difference of 5 cm. In the course of the disease in this patient, these deformities developed due to the asymmetrical involvement of the right lower femoral growth plate as a result of Ollier’s disease. 

Intervention was required, as the necessary height of her orthotic inserts had become very high and restricted function. In addition, the severe and continually worsening malposition carried the risk of fracture (Figure 1).

From the various procedures available to correct this, we opted for the gentlest and most effective method for this patient, which involves using the Precice (Nuvasive) intramedullary lengthening nail for simultaneous correction of the malposition. To do this, we first attached an external fixator during the operation. We used this to acutely correct the malposition and were then able to insert the retrograde lengthening nail via an approach in the knee joint, with the bone already in the corrected position. The patient recovered quickly from the operation. Fortunately, the entire post-operative development of the patient was so smooth that we actually had to ask the patient, who has excellent mobility with her walking aids, to slow down in her everyday life. In the end, we were able to lengthen the leg by 1 mm a day via the external control device without pain, resulting in an overall increase of 5 cm (Figure 2).