ObjectiveTo investigate the effectiveness of the Evans lateral lengthening calcaneal osteotomy (E-LLCOT) in treatment of talocalcaneal coalition (TCC) with hindfoot valgus deformity.MethodsBetween January 2014 and October 2017, 10 patients (13 feet) of TCC with hindfoot valgus deformities underwent E-LLCOTs. There were 6 males (8 feet) and 4 females (5 feet) with an age of 13-18 years (mean, 15.8 years). The disease duration was 10-14 months (mean, 11.5 months). The foot deformity was characterized by hindfoot valgus, forefoot abduction, and collapse of the medial arch. Pain site was the tarsal sinus in 4 feet, TCC in 5 feet, and ankle joint in 4 feet. There were tightness of the gastrocnemius in 3 cases (4 feet) and Achilles tendon in 7 cases (9 feet) on Silverskiold test. The preoperative American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score was 46.54±9.08 and visual analogue scale (VAS) score was 6.54±0.88 after walking 1 kilometer. The AOFAS ankle-hindfoot score and VAS score were adopted to evaluate the postoperative function of the foot. The talar-first metatarsal angle (T1MT), talonavicular coverage angle (TCA), talar-horizontal angle (TH), calcaneal pitch angle (CP), and heel valgus angle (HV) were measured after operation.ResultsAll incisions healed by first intention. All patients were followed up 12-30 months (mean, 18 months). At last follow-up, the AOFAS ankle-hindfoot score and VAS score were 90.70±6.75 and 1.85±0.90, respectively, showing significant differences when compared with preoperative scores (t=−23.380, P=0.000; t=35.218, P=0.000). X-ray films showed that the osteotomy healed at 2-4 months (mean, 3 months) after operation. At last follow-up, the T1MT, TCA, TH, and HV were significantly lower than preoperative ones (P<0.05), and the CP was significantly higher than preoperative one (P<0.05). During the follow-up, the pain did not relieve obviously in 1 patient (1 foot), and the cutaneous branch of the sural nerve injured in 1 patient (1 foot).ConclusionFor TCC with severe hindfoot valgus deformity, E-LLCOT can effectively correct deformity and relieve pain.