Giant calcific insertional Achilles tendinopathy with Haglund’s deformity following childhood tendon lengthening: a rare case report

BACKGROUND: Calcific insertional Achilles tendinopathy (CIAT) is a rare and challenging condition characterized by calcium hydroxyapatite deposition at the Achilles tendon's calcaneal insertion. While typically affecting older individuals, its occurrence in younger patients is uncommon, particularly with large calcific lesions. CASE PRESENTATION: We report a rare case of a 36-year-old male presenting with progressive left Achilles tendon insertional pain and swelling. The patient had a history of Achilles tendon lengthening surgery in childhood. Imaging revealed large, multifocal calcific deposits within the tendon. Surgical intervention involved a posterior midline longitudinal approach with complete debridement of calcified lesions, Haglund deformity resection, and flexor hallucis longus (FHL) tendon transfer. Histopathology showed myxoid degeneration, neovascularization, and mature ossified tissue. At 3-month follow-up, the patient exhibited significant improvement in pain, function, and range of motion. CONCLUSION: This case highlights a rare presentation of delayed, extensive CIAT in a young adult likely related to previous surgical trauma and poor intraoperative hemostasis. It underscores the importance of recognizing the long-term sequelae of childhood tendon surgery and demonstrates the efficacy of a combined surgical strategy incorporating calcific debridement, Haglund resection, and FHL transfer for restoring function.