Surgical correction of valgus deformities of the knee in Polyostotic Fibrous Dysplasia

Coxa vara and shepherd’s crook deformity represent the most common femoral deformities in patients affected by polyostotic fibrous dysplasia (PFD) and McCune Albright syndrome (MAS). The tibia is also commonly affected, with antero-medial bowing and valgus deformity. Surgical treatment of these deformities are technically demanding and, in most cases, intramedullary nails are the preferred method to stabilize corrective osteotomies. Genu valgus may also be present, as a residual defect after the surgical correction of the aforementioned deformities. The aim of our study was to report the outcomes obtained in five patients with PFD or MAS operated on for complex deformities of the lower limbs with an associated residual genu valgum greater than 15°. It was surgically treated by distal femoral or proximal tibial osteotomy stabilized with a screw plate. The osteotomy was performed distal to the intramedullary nail in femurs, while it was performed after removing the intramedullary nail in the proximal metaphysis of the tibia. In latter cases, the intramedullary device was reinserted at least 6 months after surgery. At follow-up, the femoro-tibial angle was corrected in all cases and the patients were satisfied with the final result. Two patients showed mild limping, unrelated to the alignment of the knee. In our opinion, residual valgus deformities of the lower limb greater than 15 degrees should be corrected to improve function and cosmetic appearance of these patients. The osteotomy of the distal femur or of the proximal tibia stabilized by a screw-plate represent the treatment of choice for the correction of these deformities.