Bunion Surgery: Check These Radiographic Parameters Intraoperatively to Avoid Recurrence
Performing the surgery and assessing intraoperative radiographs might aid in our struggle to obtain a good result. But what should we look for? Which radiographic parameters should we focus on?
As noted by Park and Lee, certain predictors of recurrence have been identified: a large preoperative hallux valgus angle (HVA)2; insufficient correction of the HVA3, the intermetatarsal angle (IMA)4, sesamoid position5, and the distal metatarsal articular angle (DMAA)6; severe metatarsus adductus7; and a round-shaped metatarsal head8. However, previous studies mainly involved the evaluation of weight-bearing radiographs, which, in fact, are difficult to imitate in the operating room.
In this Level-III study, Park and Lee performed a comprehensive retrospective analysis to identify risk factors of recurrence and to clarify whether recurrence after surgery can be predicted using radiographic parameters assessed on immediate postoperative non-weight-bearing radiographs. They reviewed 105 consecutive patients (131 feet) with symptomatic, moderate to severe hallux valgus deformity (an HVA of ≥20° or an IMA of ≥12°) in whom a proximal chevron osteotomy of the first metatarsal combined with a distal soft-tissue procedure was performed by a single surgeon between January 2008 and December 2009. A closing-wedge osteotomy of the proximal phalanx was performed in 70 patients (80 feet) in whom residual hallux valgus deformity was apparent after the metatarsal osteotomy.
Recurrence of hallux valgus was defined as an HVA of ≥20°. Feet were allocated to a nonrecurrence or recurrence group. Changes in the HVA, IMA, and sesamoid position over time were analyzed by comparing values measured preoperatively; immediate postoperatively; at 6 weeks and 3 and 6 months postoperatively; and at the last follow-up in both groups. The preoperative and immediate postoperative HVA, IMA, and sesamoid position, the preoperative metatarsus adductus angle, and the immediate postoperative DMAA were compared between the 2 groups. Cutoff values for recurrence were identified for each radiographic parameter, and the relative risks of recurrence posed by preoperative and postoperative radiographic parameters were determined. Additional analyses were conducted to assess the intraobserver and interobserver reliabilities of the radiographic measurements and to determine the effect of proximal phalangeal osteotomy.
All radiographs were made at a single facility, using the same radiographic protocol. Weight-bearing dorsoplantar radiographs were made preoperatively, at 3 and 6 months after surgery, and at the last follow-up. Non-weight-bearing dorsoplantar radiographs were made immediately postoperatively and at 6 weeks after surgery.
This study shows that recurrence after proximal chevron osteotomy for hallux valgus can be predicted from immediate postoperative non-weight-bearing radiographs, which can be closely related to intraoperative radiographs, so we can modify correction as needed in the operating room.
The risk factors for hallux valgus recurrence were severe preoperative metatarsus adductus and severe preoperative hallux valgus deformity as assessed by preoperative HVA as well as insufficient correction of the HVA and sesamoid position as assessed immediately postoperatively. Using an immediate postoperative HVA cutoff value of 8°, feet with an HVA of ≥8° had an odds ratio of recurrence of 28 times that of feet with a HVA of <8°. These findings indicate that correcting risk factors such as the IMA and DMAA in the operating room is not enough to avoid recurrence; the HVA is also important!
All surgeons treating hallux valgus should be aware of these measurements on perioperative radiographs for all bunion procedures.