Aim: To analyse retrospectively patients after subtalar extra-articular arthrodesis in CP patients.

Material and methods: The operation was designed to correct pronated valgus foot. Followed cohort involved 43 patients with 72 affected and operated feet. Subtalar arthrodesis was based on insertion of bicortical graft obtained from iliac wing in the corrected position of the foot. Immobilisation in POP cast continued for 6 weeks postoperatively. Patients were followed clinically and radiographically in standing position before the operation, and after that at regular intervals. Clinical examination involved estimation of heel valgus, foot-prints, videodocumentation. Lateral talo-calcaneal angle (TC) and calcaneal-bottom angle (CB) were measured on radiographs. Moreover qualitative-descriptive classification was used (good, fair, poor).

Results: The median of preoperative TC angle was 44,5° at right foot and 48,0° at left foot. The median of postoperative angle changed to 29,5° at right foot and 29,0° at left foot. The difference in TC angles before and after operation was statistically significant. The median of preoperative CB angle was 7,5° at right foot and 7,0° at left foot. The median of postoperative CB angle was 10,5° at right foot and 7,5° at left foot. The difference in CB angles before and after operation was not statistically significant. Operation failed in two cases due to collapse or migration of the graft. Significant improvement in this study was found in 59 (82%) of cases.

Discussion: Plenty of reports concerning the use of classical Grice-Green operation in different modifications were reported. This study is based on the use of bicortical cortico-cancellous graft, which provided good stability as well as a smooth incorporation to the neighbouring bones. The correction in TC angle dominated over change in CB angle.

Conclusion: Subtalar extra-articular arthrodesis showed in mid-term follow up very good results.