ObjectiveTo evaluate the effectiveness of the channel-assisted minimally invasive repair (CAMIR) technique combined with flexor hallucis longus (FHL) tendon transfer in the treatment of Achilles tendon sleeve avulsion.Methods A retrospective analysis was conducted on 17 patients with Achilles tendon sleeve avulsion who underwent CAMIR technique combined with FHL transfer between January 2019 and January 2023. The cohort comprised 13 males and 4 females, aged 32 to 65 years (mean, 49.7 years). Etiologies included sports-related injuries in 15 cases and blunt trauma in 2 cases. The interval from injury to surgery ranged from 4 to 368 days (median, 15 days). All patients exhibited calcification at the Achilles tendon insertion site, with 7 cases complicated by Haglund deformity. Postoperative complications were meticulously monitored, and tendon healing was assessed via MRI. Clinical outcome were evaluated using the visual analogue scale (VAS) score for pain, Tegner activity level rating scale, ankle activity score (AAS), American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score, Victorian Institute of Sport Assessment-Achilles (VISA-A) score, and subjective clinical scoring systems preoperatively and at last follow-up. Results The operation time was 50-62 minutes (mean, 56 minutes), and the intraoperative blood loss was 5-50 mL (mean, 19.7 mL). All patients were followed up 12-67 months (mean, 38 months). No postoperative complications, such as Achilles tendon re-rupture, incision infection, deep vein thrombosis, heel raise insufficiency, or sural nerve injury, were observed. At last follow-up, MRI examination confirmed satisfactory tendon healing in all cases. Significant improvements were noted in VAS scores, Tegner activity level rating scale, AAS scores, AOFAS ankle-hindfoot scores, and VISA-A scores compared to preoperative ones (P<0.05). At last follow-up, the subjective clinical score ranged from 6 to 10 (median, 9). ConclusionThe CAMIR technique combined with FHL transfer is a good treatment for repair of Achilles tendon sleeve avulsion, with good recovery of ankle function and few complications.