Introduction: Planovalgus is a clinical deformity on weightbearing. Extra-articular calcaneal lengthening osteotomy, is a recognised surgical treatment for symptomatic flat feet. The aim of this study was to assess the difference in pedal pressures and radiographic parameters in the assessment of patients undergoing lateral column lengthening for planovalgus deformity.

Methods: Operative records of one surgeon were reviewed over a 5 year period to identify those who had undergone a lateral column lengthening procedure. 10 patients, 14 feet were identified. Patients were recalled for post-operative pedobarography and pre- and post-operative X-rays were identified. Peak plantar pressures were measured at 8 sites and a line plotted to show maximum deviation of pressure progression from the anatomical axis of the foot. 5 angles on X-rays were measured by 2 observers on 2 occasions.

Results: Difference in pressure under the 3^rd metatarsal head (p=0.0004), hallux (p=0.02) and medial midfoot (0.001) suggested a highly significant change. Results for the first (p=0.41) and second (p=0.91) metatarsal heads showed no change. The centre of pressure maximum deviation, plotted using a line drawn between the second toe and the rear of the heel was found to be highly significant postoperatively (p=0.00051) indicating that load bearing shifted from medial to lateral. Changes in X-ray angles of the lateral talo-1^st metatarsal angle(p=0.006), calcaneal pitch(p=0.002), AP talocalcaneal angle(0.0001) and talonavicular coverage(p=0.003) were all highly significant.

Discussion: Lateral lengthening in adolescent feet changes the pedal pressures in an advantageous way.