[Scarf osteotomy for the treatment of forefoot deformity].

PURPOSE OF THE STUDY

The outcome of surgical treatment in hallux valgus is sometimes unsatisfactory for both the patient and the surgeon. The valgus position of the big toe in the metatarsophalangeal joint is associated with a deviation to varus of the first metatarsal, resulting in the space between the first and second metatarsals called the intermetatarsal (IMT) angle. In most patients the angle is between 10 and 20 degrees. These patients were indicated for scarf osteotomy as this method has been reported to achieve good outcomes. The results are compared with the relevant literature data on foot osteotomy.

MATERIAL

Our group involved 62 scarf osteotomies carried out on 49 patients who were followed up for an average of 18 months (range, 6-36 months). Three patients underwent surgery on both feet in one stage, five had bilateral surgery in two stages. The average pre-operative IMT angle was 16 degrees (range, 9-21 degrees) and the average hallux valgus angle was 37 degrees.

METHODS

The patients were indicated for surgery on the basis of subjective complains and weight-bearing radiographs. Scarf osteotomy was performed by the Barouk technique. From a signle incision in the first intermetatarsal space, the lateral articular capsule was released, adductor tendon was dissected and sesamoid bones were reduced. The first metatarsal was exposed from an incision along its medial axis, the bunion was excised and Z-osteotomy of the metatarsal was performed. The distal fragment was shifted laterally, fixed with two 3.5 mm Poldi screws, and the capsule was closed under tension with transosseal suture. If necessary, an additional procedure on the big toe phalanges or osteotomy of the other metatarsals are carried out. From the second post-operative day the patients were allowed to walk on the heel, after removal of sutures they walked wearing a special sandal and, from the third week onwards, full weight-bearing was allowed. The average hospital stay lasted 4 days. The evaluation of post-operative results was based on radiograms, subjective feelings of the patients and clinical assessment of the range of big toe motion.

RESULTS

Out of 62 operations carried out on 49 patients (average age, 41.5 years), 23 were performed on the right and 23 on the left foot; bilateral surgery was carried out in three patients in one stage and in five patients in two stages. Simultaneously, the Weil osteotomy was performed on six feet, Akin osteotomy of the big toe phalanges on five feet, Braggard surgery of the second toe on three feet, and scarf osteotomy of the fifth metatarsal on three feet. All feet were indicated for scarf osteotomy because of pain and, in 56 feet, also esthetic reasons were involved. The patients' subjective post-operative assessments were as follows: satisfaction with the outcome in 58 feet, pain associated with tight shoes in two feet, pain while walking in six feet, and dissatisfaction with the big toe shape in one patient.The average IMT angle of 16 degrees and hallux valgus angle of 37 degrees on the pre-operative radiograms showed improvements to 9 degrees and 18 degrees, respectively, on the post-operative X-ray. The sesamoid bones were reduced in all cases. After surgery the average range of motion was restricted as follows: plantar flexion by 7 degrees (to 23 degrees) and dorsal flexion by 6 degrees (to 54 degrees). The complications included one fracture of the head requiring osteosynthesis, one failure of fixation with repeat valgus osteotomy, three cases of insufficient correction of a valgus position that had to be treated by additional osteotomy of the first toe phalanges.

DISCUSSION

Out of other types of osteotomy (Funk, Dega, spike osteotomy), outcomes similar to scarf osteotomy have been achieved only by the Austin procedure. However, in this, shifting of the distal fragment is limited and the results show that the Austin method should be preferred in deformities with an IMT angle of about 10 degrees. Scarf osteotomy in addition allows for early weight-bearing, does not produce shortening of the first metatarsal but permits its elongation and elevation by oblique osteotomy, if necessary. It can also be used for the fifth metatarsal. The drawbacks include a more complicated surgical technique and higher risk of complications; shifting of the distal fragment is also limited and, for this reason, scarf osteotomy is not effective in deformities with an IMT angle higher than 20 degrees.

CONCLUSIONS

Scarf osteotomy is an effective procedure for a moderate valgus deformity of the big toe with an IMT angle between 10 and 20 degrees. It permits early weight-bearing of the treated extremity. It requires exact pre-operative planning and strict adherence to the operative technique.