Improvement of hindfoot alignment after isolated lateral column lengthening for flat foot deformity.

BACKGROUND

Lateral column lengthening (LCL) is reported as an effective operative treatment for flat foot deformity and can alter hindfoot alignment (HA). However, there are few reports studying changes in HA after LCL compared to other radiographic parameters.

PURPOSE: To investigate changes in HA and other radiographic parameters following isolated LCL in pediatric flatfoot deformity.

STUDY

DESIGN

Retrospective case series.

METHODS

A total of 46 surgical corrections in 28 patients who underwent isolated LCL between 2008 and 2013 were reviewed. The mean patient age was 9.7 years (range, 8 to 13), and the mean follow-up was 41 months (range, 24 to 171). Radiographic parameters-including HA angle, HA ratio, and moment arm-were compared pre- and postoperatively. Calcaneocuboid (CC) joint subluxation was also measured and correlated with bone graft (BG) size.

RESULTS

HA angle and the moment arm improved significantly following the LCL. Immediate BG size on plain radiographs had significant moderate positive relationships with the moment arm (p=0.001). The minimal BG sizes to make a postoperative change of the moment arm on immediate postoperative non-weight bearing dorsoplantar and lateral plain radiographs were 8.09 mm and 8.41 mm, respectively.

CONCLUSION

In flat foot deformity, hindfoot alignment significantly improves after LCL, except for the hindfoot alignment ratio. However, a residual hindfoot valgus deformity persists despite these improvements. The moment arm between the weightbearing axis of the leg and the contact point of the heel improved significantly showing positive correlation with a BG size regardless of CC joint subluxation.