Ki Hyuk Sung, MD Department of Orthopaedic Surgery Seoul National University Bundang Hospital

1. Talar morphologic changes after tendo-Achilles lengthening for long-standing equinus deformity in patients with residual poliomyelitis Ki Hyuk Sung, MD Department of Orthopaedic Surgery Seoul National University Bundang Hospital

2. Introduction • Coronal angular deformity of the lower limb is a common finding in growing children • Permanent (irreversible) hemiepiphysiodesis • Temporary (reversible) hemiepiphysiodesis using staples, percutaneous screws, or a tension band plate (eight-plate)

3. Introduction • Measuring the rate of correction is necessary to predict the time to end point • The rate of angular correction has been calculated simply by averaging. • Other factors (age, surgical method, direction of deformity, etiology, physis) must be considered while estimating the rate of correction

4. Introduction • A linear mixed model (LMM) is useful in settings where multiple correlated measurements are made on the same statistical units • LMM consists of fixed effects and random effects • Estimation of the correction rate by using a mixed model application may confer more practical information to clinicians

5. Purpose • To investigate the talar morphologic changes after TAL for long-standing equinus deformity in patients with RP • To investigate whether the severity of preoperative equinus deformity affect occurrence of symptomatic anterior impingement.

6. Material and methods

7. Inclusion criteria • Consecutive patients with residual poliomyelitis, who underwent tendo-Achilles lengthening for equinus foot deformity since 2003 • Patients who had preoperative and postoperative weight bearing lateral foot-ankle radiographs • Patients with a minimum follow-up of 6 months

8. Exclusion criteria • Patients with inadequate foot-ankle radiographs for measurement • Patients with history of previous foot surgery • Patients who had concomitant anterior bony spur excision with TAL

9. Radiographic measurement • Lateral foot weight bearing radiograph • Talocalcaneal angle • Plantigrade angle • McDermott grade • Presence of anterior blocking spur

10. Talocalcaneal angle

11. Plantigrade angle

12. McDermott grade • grade 1, anterior tibial spur measuring less than 3mm • grade 2, anterior tibial spur measuring more than 3mm • grade 3, anterior tibial spur with secondary talar spur (kissing lesion) • grade 4, panarthritis

13. McDermott grade

14. Anterior blocking spur

15. Statistical analysis • Comparison between preoperative and postoperative McDermott grade • Wilcoxon signed ranks test • Comparison of preoperative radiographic measurements between the patients with and without anterior ankle pain, and between the patients with and without anterior blocking spur • Independent t-test

16. Results

20. Conclusion • Most of patients with RP showed the anterior ankle impingement after TAL for long-standing equinus deformity • The presence of symptomatic anterior ankle impingement was significantly associated with the severity of the equinus deformity.

21. Conclusion • Therefore, for the RP patients with severe long-standing equinus deformity, surgeons should consider the possibility of subsequent anterior procedure for anterior impingement after TAL.

22. Thank you for your attention!