Low-Dose Radiotherapy for Benign Achillodynia: A Single Center Experience With Prospective Follow-Up.

Purpose To evaluate the effectiveness and safety of low-dose radiotherapy (LDRT) for refractory achillodynia and to examine whether pain response differs by pretreatment pain duration or common dose and fractionation schedules. Methods Consecutive patients treated for Achilles tendinopathy at a single institution between 2020 and January 2026 were identified and contacted in early 2026 for updated outcome and toxicity assessment. Pain was assessed using a 0 to 10 visual analog scale (VAS) before radiotherapy and during follow-up. Treatments were delivered two to three times weekly according to German Society for Radiation Oncology (DEGRO)-consistent schedules. Response, paired VAS change, toxicity, and subgroup differences were analyzed. Results Seventy-one patients received radiotherapy for 81 treated feet, including 10 bilaterally treated patients. Median baseline VAS was 7, and most patients had undergone prior conservative therapies. The most common schedule was 6 × 1 Gy. At a median follow-up of 3 months after the last radiotherapy course, 79% (n = 64) of feet responded, 13.6% (n = 11) did not respond, and 7.4% (n = 6) were lost to follow-up. Among 61 feet with paired VAS data, the median pain improvement was 4 points. No increased pain or treatment-related toxicity was reported. Pain improvement did not significantly differ by pain duration of ≤12 versus >12 months or by 6 × 1 Gy versus 8 × 0.5 Gy. Conclusion LDRT provided meaningful pain relief without observed toxicity in this real-world cohort. These findings support LDRT as a potential option after failed, contraindicated, or poorly tolerated conservative treatment with an effect size similar to what has been reported for fasciopathies in randomized controlled trials.