A different reason for subtalar joint pain: Calcaneal sulcus cysts and treatment

PURPOSE: Interosseous cysts located in calcaneal sulcus are radiologically diagnosed as ganglion cysts. However there is not enough evidence in the literature about their treatment and how they occur. We think that these cysts may cause hind foot pain by causing peripheral bone edema of the calcaneus or mucoid fluid production which further increases subtalar intra articular pressure. METHODS: We performed surgical treatment for calcaneal sulcus cyst to 6 patients in 2015. All patients were evaluated with AP and lateral ankle X-ray and MRI preoperatively. RESULTS: We found that all cysts were arisen from insertion of the interosseous talocalcaneal ligament in calcaneal sulcus by MRI (figure 1). There were accompanying bone edema in 3 patients whose cysts were larger. We performed subtalar arthroscopy with drilling to 2 of the patients whose cysts were small. 3 patients were operated with curettage and grafting (autograft) by lateral approach. Last patient were treated with drilling by lateral approach. We detected the mucoid fluid stretching joint capsule when we reach subtalar joint during open surgery (figure 2). Interosseous talocalcaneal ligament were intact in all patients treated even treated with open surgery or arthroscopy. Therefore cystic changes were not seen. In order to avoid ligament damage, cysts were curated and grafted with spongious bone through a small bone window. In a short follow-up period, complete pain relief without recurrence was observed. CONCLUSIONS: During subtalar arthroscopy we saw that anterior of the posterior talar facet was impinged to talocalcaneal ligament insertion on the calcaneal sulcus. We suggest that cysts might occur as a result of recurrent oscillating trauma as Van der Vis et al. were postulated.