Diagnosis and operation results for chronic lateral ankle instability with subtle cavovarus deformity and a peek-a-boo heel sign

Cavovarus deformity is considered an anatomical risk factor for chronic lateral ankle instability (CLAI). However, subtle deformity can be difficult to detect, and its correction is controversial. The current study aimed to evaluate clinical and radiographic outcomes of a modified Broström procedure (MBP) with additional procedures for CLAI with subtle cavovarus deformity and a positive peek-a-boo heel sign. We reviewed the records of 15 patients who underwent MBP with additional procedures for CLAI with a positive peek-a-boo heel sign between August 2009 and April 2015. Consecutive physical and radiographic examinations were performed. The visual analog scale (VAS) for pain, the American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, and the Karlsson-Peterson (KP) ankle score were applied to assess clinical outcomes. Weight bearing radiographs, hindfoot alignment view, and ankle stress radiographs were also examined. The mean follow-up period was 58.5 months. Calcaneal lateral closing wedge osteotomy was performed in seven patients to correct fixed hindfoot varus, and first metatarsal dorsiflexion osteotomy was performed in 11 patients to correct plantarflexion of the first ray. Three patients underwent both procedures. Mean VAS, AOFAS, and KP ankle scores improved significantly (p=0.001), and instability did not recur. Radiographically, all stress parameters improved significantly (p=0.007). Simultaneous correction of a positive peek-a-boo heel sign and cavovarus deformity with MBP for CLAI improves clinical outcomes and prevents recurrent instability. A comprehensive evaluation and cautious approach for subtle cavovarus deformity should be followed when treating patients with CLAI. This trial is registered on Clinical Research Information Service (CRiS, KCT0003287).