Correction Amount After Calcaneal Lengthening for Planovalgus Foot Deformity in Cerebral Palsy

1. Amount of correction after calcaneal lengthening for planovalgus foot deformity in patients with cerebral palsy Ki Hyuk Sung, MD Seoul National University Bundang Hospital

2. Introduction • Planovalgus foot deformity is common in patients with cerebral palsy • A complex 3-D malalignment • hindfoot valgus, plantar flexed talus • midfoot planus and pronation • relatively short lateral column • forefoot abduction and supination

3. Introduction • Medial callosities • Hallux valgus • Shoe wear • Pain • Gait disturbance due to lever arm dysfunction

4. Introduction • Surgical options • medial displacement osteotomy of calcaneus • subtalar extra-articular arthrodesis • lengthening of the lateral column • triple arthrodesis • Calcaneal lengthening osteotomy • most commonly used to correct the deformity and not sacrifice joint motion in patients with CP

5. Introduction • Additional procedures, such as, medial soft tissue procedure, medial bony procedure, or triple arthrodesis could be performed concomitantly with calcaneal lengthening depending on severity of deformity. • However, there has been no guideline to determine the necessity of these procedures

6. Purpose of the study • To investigate the amount of correction after calcaneal lengthening for the treatment of planovalgus foot deformity in patients with CP • To guide a surgical indication in terms of the severity of the foot deformity

7. Materials and Methods • Retrospective design • Inclusion • patients with cerebral palsy who underwent calcaneal lengthening for planovalgus deformity between 2003 and 2011 • patients who had preop and postop weight bearing AP and lateral foot radiographs

8. Materials and Methods • Exclusion • patients who had concomitant medial column procedures with calcaneal lengthening • patients with a history of previous foot surgery • patients with inadequate foot radiographs for measurement

9. Radiographic measurement • Lateral foot weight bearing radiograph • Calcaneal pitch angle • Lateral talocalcaneal angle • Lateral talus-first metatarsal angle • Naviculocuboid overlap • Relative calcaneal length • Calcaneocuboid subluxation • Anteroposterior foot weight bearing radiograph • Anteroposterior talus-first metatarsal angle

10. Calcaneal pitch angle

11. Lateral talocalcaneal angle

12. Lateral talus-first metatarsal angle

13. Naviculocuboid overlap (B/A)

14. Relative calcaneal length (a/b)

15. Calcaneocuboid subluxation

16. AP talus-first metatarsal angle

17. Operative procedure

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19. Corrected group • a group of patients whose radiographic indices improved beyond the value of normal alignment after calcaneal lengthening • Under-corrected group • a group of patients whose radiographic indices did not reach the value of normal alignment

20. Reliability of radiographic measurement • Inter-observer reliability (3 observer) • 36 radiographs • ICC (intraclass correlation coefficient) & 95% confidence interval

21. Statistical analysis • Comparison between preop radiographic measurement and postoperative measurement • Paired t-test • Define the cut-off values of the preop radiographic measurements between the corrected and the under-corrected group • ROC curve

22. Results

27. Conclusions • Calcaneal lengthening with concomitant peroneus brevis lengthening is the effective procedure for correcting planovalgus foot deformity while preserving subtalar joint motion in patients with cerebral palsy.

28. Conclusions • For the patients with more than 23˚of AP talus-first MT angle, more than 36˚of Lat. talus-first MT angle, and more than 72% of NC overlap, the additional procedures should be considered due to the possibilities of insufficient correction with calcaneal lengthening alone.

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