Giant Calcific Insertional Achilles Tendinopathy Associated With Diabetes Mellitus: A Clinical and Surgical Case Report

Abstract INTRODUCTION: Calcific Insertional Achilles Tendinopathy (CIAT) is a rare tendon pathology characterized by calcific deposition at the attachment site of the Achilles tendon to the calcaneus (enthesis). Diabetes Mellitus (DM), one of the common metabolic diseases, adversely affects tendon structure and biomechanics through various pathways, such as increased oxidative stress and the accumulation of advanced glycation end products. CASE: We report the case of a 47-year-old male patient with DM, treated with a DPP-4 inhibitor and metformin, who presented with a long-standing history of atraumatic heel pain and swelling. Clinical examination revealed that the pain and swelling were localized to the calcaneal enthesis of the Achilles tendon and increased with passive dorsiflexion. Radiological imaging demonstrated giant calcified mass measuring approximately 5 × 3 × 1.5 cm at the calcaneal enthesis of the Achilles tendon. During surgical intervention, the distal one-third of the Achilles tendon was incised using a posterior midline longitudinal approach, followed by excision of the calcified tissue. As approximately 75% of the Achilles tendon insertion was observed to be preserved, the preoperatively planned V-Y lengthening technique was abandoned. Repair was performed by re-fixating the tendon tissue, which had been incised and elevated from the calcaneus, to the calcaneus using a knotted metallic anchor. Histopathological examination revealed osteochondromatous and tendinoligamentous tissues; no findings suggestive of malignancy were detected. At a 7-month postoperative follow-up, the patient showed significant clinical improvement in pain, function, and range of motion. CONCLUSION: This case highlights a clinically rare giant-sized CIAT and its possible association with the adverse effects of DM on tendon biomechanics. Even in the presence of giant CIAT, in cases where the insertion is largely preserved, anchor-supported partial repair may be a feasible surgical option instead of extensive reconstruction.