Sports-Related Posterior Ankle Pain: Diagnosis and Management of Lateral Calcaneal Branch Neuropathy of the Sural Nerve (A Case Series).

Abstract

Posterior ankle pain has varied etiologies, with sural nerve (SN) entrapment contributing to posterolateral ankle discomfort. The SN is a pure sensory nerve that innervates the lateral ankle and foot up to the fifth metatarsal. Although SN pathologies are known, specific clinical features and management of neuropathy affecting the lateral calcaneal branch of the sural nerve (LCBSN), which supplies the lateral heel, are less defined. This condition is often exacerbated by repetitive ankle dorsiflexion in sports or external compression from tight footwear. We hypothesized that LCBSN lesions cause a distinct pattern of heel pain that is uniquely aggravated by ankle dorsiflexion or shoe contact, thereby distinguishing this entity from other causes of posterior ankle pain. This retrospective case series included 23 patients. We reviewed records of 23 patients presenting with posterolateral ankle pain and localized LCBSN tenderness. Key diagnostic features included pain aggravation with ankle dorsiflexion or shoe contact, lacking motor deficits. Diagnosis was primarily confirmed by immediate, significant pain relief after local anesthetic injection around the LCBSN. Symptom severity (0-4 scale) and American Orthopaedic Foot & Ankle Society (AOFAS)-hindfoot scores were assessed at 1 month and 1 year post-treatment. Surgical intervention was performed for recurrent pain after 6 months of conservative management. Improvement (<i>P</i> < .05) in both symptoms and AOFAS-hindfoot scores was observed at 1-month and 1-year follow-ups. Six patients required surgical treatment for recurrent symptoms. Pathologic findings included arterial wall thickening with dense perineural adhesions and scarring (3 cases), neuroma formation (2 cases), and nerve entrapment due to adhesions (1 case). Conservative treatment was effective for the remaining patients. Accurate and timely diagnosis of LCBSN lesions is crucial for effective treatment and enabling prompt return to sports activities. A diagnostic, small volume local anesthetic injection may serve as a practical diagnostic adjunct and an initial therapeutic measure for this clinically significant condition.