Shortening of the First Metatarsal During the Correction of Hallux Valgus: Never Be Allowed?

Category: Bunion; Midfoot/Forefoot Introduction/Purpose: Transfer metatarsalgia is one of the potential complications after hallux valgus correction, of which shortening of the first metatarsal is thought to be an important cause. Thus many surgeons believe that shortening of the first metatarsal should be avoided or kept to a limited extent. However, we found that many patients with first metatarsal shortening did not really develop postoprative transfer metatarsalgia, but instead had easier correction of the hallux valgus in operation and better outcomes and even more benefit in walking due to reduced tension around the metatarsophalangeal joints and improved joint mobility. Up to now, few investigations have truly conducted large-scale long-term follow-up on this issue, and little is known about the appropriate level of first metatarsal shortening. Methods: This retrospective study included 835 feet in 712 patients who were treated with first metatarsal osteotomies without Weill osteotomies for hallux valgus during the period of January 2013 to January 2023. Standard weight-bearing dorsoplantar and lateral radiographs were collected before and at different time more than six months after surgery. The hallux valgus angle (HVA), intermetatarsal 1-2 angle (IMA) were evaluated. The absolute length of the first metatarsal as well as its relative length to the second metatarsal was both measured. Clinical evaluation included preoperative and postoperative symptom assessment, the range of motion (ROM) at metatarsophalangeal joint and AOFAS Scale. The incidence of postoperative complications was also specifically recorded, as well as information on where the metatarsalgia occurred, the nature of the pain, and how the pain occurred and relieved. Patients were divided into different subgroups according to the level of shortening of the first metatarsal. Results: The level of shortening of the first metatarsal was positively correlated with the reduction of the HVA, and inversely correlated with the recurrence rate. Those with shortening of 3 mm or more had significantly better first metatarsophalangeal joint mobility compared with those without shortening. Patients with a shortening of 6 mm or more were significantly more likely to have a metatarsalgia under the central metatarsal heads postoperatively (5.88% vs 3.01%). 5 feet (2.67%) developed recurrence of the hallux valgus in patients with a shortening of 6 mm or more, compared with 23 feet (4.07%) in patients with a shortening of 6 mm or less, and 6 feet (7.23%) in patients without shortening. Conclusion: Taking into account the correction of HVA, joint mobility, postoperative recurrence and the risk of metatarsalgia, it is recommended that the relative length of the shortening in the first metatarsal osteotomy can be extended up to 6 mm, especially in patients with severe hallux valgus, in order to obtain the easier correction of the HVA in the operation and best therapeutic results and function.