Current Concepts With Revisional Bunion Surgery
Consider sagittal plane malunions in which the first ray is positioned dorsal or plantar to the plane of the lesser metatarsals. A plantarflexed metatarsal can cause sesamoiditis and/or a loss of hallux purchase. A dorsiflexed metatarsal (elevatus) can result in hallux limitus, loss of hallux purchase and/or lesser metatarsal overload. Dorsiflexed metatarsals are common with base wedge osteotomies (especially with monofilament wires) due to early walking and plastic deformation.
Elevatus is one of the easier conditions to correct, whether the index operation was an osteotomy bunionectomy or Lapidus bunionectomy. One can correct elevated distal metatarsal osteotomies with reverse wedge osteotomies (but these can create additional shortening) or opening wedge osteotomies. Surgeons need to evaluate each independently. I have found one can successfully revise elevated base osteotomies with an inferior translatory Lapidus arthrodesis. One can translate the first ray inferiorly by approximately 50 percent at the first tarsometatarsal joint. Nonetheless, the goal in each case is to get the first metatarsal head present on the ball of the foot. Sometimes concomitant lesser metatarsal osteotomies may be necessary to achieve this.
A patient had a distal metatarsal osteotomy bunionectomy (Reverdin), which resulted in a big toe that lifted off the ground (see left photo). Retrograde pressure caused sesamoiditis. The elevated toe was due to a malunion of the osteotomy where the first metatarsal head was elevated (dorsiflexed). The revision bunion surgery involved a dorsal opening wedge osteotomy to realign and plantarflex the first metatarsal head. I used a harvested autogenous bone graft for the wedge. The results of the surgery alleviated the patient’s pain and allowed the big toe to purchase the ground.
Pertinent Insights On Managing Hallux Varus
In simplest terms, hallux varus is an over-corrected bunion that results in the big toe pulling in the wrong direction, away from the foot. The cause is a muscle imbalance that may be from improper bone alignment and/or over-tightening the soft tissue, giving mechanical advantage to certain muscles.
Hallux varus, if we do not catch and treat it early, may progress to secondary problems with a contracted hallux metatarsophalangeal joint (MPJ) and/or hallux interphalangeal joint, a result that patients commonly consider a failed bunionectomy.
In regard to treatment for early postoperative hallux varus, consider capsulotomy with pinning. The presence of hallux varus early in the postoperative period justifies aggressive treatment in my opinion. If the root cause of the varus is from a bony malalignment, then revising those osteotomies or fusions may be indicated. When the bony alignment is good and the varus is possibly due to overtightening of medial structures, then a big toe joint capsulotomy (to release the abductor muscle pull) with pinning of the big toe joint in valgus or neutral position may be quite effective.