Planning SCARF osteotomy with the consideration of first metatarsal bone mobility

Hallux valgus is a common orthopedic disorder that has a negative impact on the quality of life. The effectiveness of conservative methods is usually low. Surgical correction allows the elimination of the cosmetic defect, pain syndrome and problems with the selection of shoes in most of cases. Osteotomy of the first metatarsal bone is the basic surgical technique for correcting static deformation of the anterior part of the foot. Scarf osteotomy is preferred by many surgeons treating these patients. This is associated with the possibility of correcting the deformation of the first metatarsal bone in 3 planes. Approaches to geometric planning of such osteotomy are described in detail in many publications. However, in some cases, surgery leads to excessive extension in the first metatarsophalangeal joint. This side effect is probably caused by excessive displacement of the distal fragment of the first metatarsal bone in the plantar direction. In order to prevent excessive extension of the first toe, we have developed an algorithm for geometric planning of scarf osteotomy, considering the mobility of the first metatarsal bone and transverse displacement of the distal fragment. This algorithm was used in the treatment of 50 patients with hallux valgus. We managed to achieve significant reduction in the frequency and degree of excessive extension of the first toe after scarf osteotomy.