The Lapidus procedure is used to correct a moderate to severe hallux valgus deformity. It is also indicated for hallux valgus associated with a hypermobility of the first ray.
The procedure involves an incision over the dorsomedial (top and inside) part of the midfoot. The first tarsometatarsal joint is exposed. This joint is then prepared for fusion. In the context of fusing this joint, the angle between the first and second metatarsal is decreased. This joint is typically then fused with two screws. It may also be fused with a plate if it is applied appropriately. In addition, the bunion is corrected through a medial incision over the great toe. which allows the joint capsule to be tightened as well as the prominent medial bone associated with the bunion to be removed. As well, it is often necessary to perform a release of the tightened structures on the lateral (outside) part of the great toe joint.
This procedure requires a period of 6 weeks of non weight-bearing or limited weight-bearing through the heel. The joint that is fused needs to heal and therefore load through the mid part of the foot has to be quite limited during this time. Once this joint has started to heal at about the 6-week mark, patients can be mobilized in a stiff-soled shoe or a walking boot. Usually, they are able to return to a regular shoe by 9-12 weeks post surgery. It is not uncommon to need to splint the great toe in its corrected position either with a toe spacer between the first and second toe or sometimes even with a bunion splint.
The general surgical complications can occur with a Lapidus procedure. This would include:
Complications that are specific to a Lapidus procedure include:
- Nonunion of the first TMT joint. This occurs in 5-10% of patients and may require either prolonged non weight-bearing or perhaps even re-operation.
- Local nerve Injury. The medial branch of the superficial peroneal nerve can be irritated creating either loss of sensation over the inside of the great toe or an irritating sensation in the inside part of the foot. This occurs in approximately 3-5% of patients.
- Recurrence of the bunion deformity