This retrospective cohort study tries to determine if there is a correlation between the effectiveness of low-dose radiotherapy (LDRT) in treating painful inflammatory or degenerative musculoskeletal disorders (MSDs) and the applied radiotherapy energy.

Between September 2019 and January 2020, a total of 91 patients with either painful inflammatory or degenerative MSDs were treated with LDRT. The inclusion criteria were patients older than 40 years with either painful inflammatory disorders such as epicondylitis humeri, plantar fasciitis or degenerative osteoarticular disorders of the wrist or ankle joints. All patients were treated with a single dose of 0·5 Gy and a total dose of 6·0 Gy (2 to 3 fractions weekly). Patients were divided into two groups. Orthovolt group was treated with 200 Kv, 15 mA and 1 mm copper filtration with different tubes according to the site to treatment using direct fields. The second group included patients treated with Linac machines with opposing fields using energies between 6 and 18 MV. The pain was evaluated before and on the last day of treatment and 4–6 months later using the Numerical Rating Scale.

91 patients compatible with the inclusion criteria were identified with a median of 60 years. The median duration of symptoms was 6 months. 46% of patients were males, and 54% were females. The Orthovolt group included 49% of the patients and the Megavoltage group 51%. Most of the patients (98%) were previously treated with other methods such as local corticosteroid injection, painkillers or physiotherapy. At the end of the treatment, 60% of the patient’s showed subjective pain relief and only 6% had a complete response. The follow-up conducted 4 to 6 months after the treatment showed that 65% of patients had a complete response and 8% had an improvement. The comparison between both studied groups shows that the used energy does not affect the response either at the end of the treatment or at the second control. The relationship between the aetiology and the early and late responses shows no difference in the early response but a better late response in patients suffering from inflammatory diseases with a p-value of 0·015. The response according to the treated location shows that patients with osteoarthritis of the ankle joint have a worse response in comparison to other examined joints and plantar fasciitis.

LDRT is an effective analgesic treatment option for both inflammatory and degenerative MSDs. There is no difference in response according to the used energy, and most of the patients show late responses 4 to 6 months after the treatment.