Single Versus Double Pin Fixation of the Calcaneocuboid Joint During Calcaneal Lengthening Osteotomy for Pediatric Idiopathic Flatfoot.

BACKGROUND

Calcaneocuboid (CC) joint subluxation is a recognized complication after calcaneal lengthening osteotomy for pediatric idiopathic flexible flatfoot, and temporary pin fixation is often performed to prevent it. This study compared postoperative radiologic outcomes at 2 years of single- and double-pin fixation of the CC joint.

METHODS

We retrospectively reviewed 50 feet from 30 patients aged 9 to 15 years who underwent calcaneal lengthening osteotomy for idiopathic flexible flatfoot with a follow-up of at least 2 years. Fourteen feet (28%) underwent single-pin fixation, and 36 (72%) double-pin fixation. Five radiographic angles were measured, and the CC joint subluxation index was calculated preoperatively and at 3 months, 1 year, and 2 years postoperatively.

RESULTS

The mean age at surgery was 11.1±1.4 years, and there were no significant differences between the single-pin and double-pin groups. At postoperative 2 years, the calcaneal pitch angle was significantly higher in the double-pin group compared with the single-pin group (16.1±3.8 degrees vs. 19.3±4.4 degrees, P =0.019), whereas no significant differences were observed in the remaining radiographic angles or in the CC joint subluxation index ( P >0.05). Number of pins, preoperative anteroposterior and lateral talo-1 st metatarsal angles, and patient age were independently associated with calcaneal pitch angle after 2 years.

CONCLUSIONS

Although the number of pins did not affect the CC joint subluxation index, double-pin fixation was associated with better maintenance of the calcaneal pitch angle at 2 years after calcaneal lengthening osteotomy for pediatric idiopathic flexible flatfoot. Considering the 3-dimensional anatomy of the CC joint and the characteristics of the calcaneal pitch angle, double-pin fixation may better maintain midfoot-hindfoot alignment after calcaneal lengthening osteotomy.

LEVELS OF EVIDENCE: Level III-retrospective comparative study.