Treatment of myofascial pain syndrome with lidocaine injection and physical therapy, alone or in combination: a single blind, randomized, controlled clinical trial

Myofascial pain syndrome (MPS) is an important cause of chronic musculoskeletal pain, characterized by hypersensitive myofascial trigger points that, when palpated, can elicit characteristic referred pain. This condition affects between 21% of patients in orthopedic clinics and up to 95% in specialized pain centers. Despite its high prevalence, controversy persists about the best treatment methods, especially regarding the efficacy of combining different therapeutic modalities. This single-blind randomized controlled clinical trial was conducted at two hospitals in Medellín, Colombia, with the aim of determining whether lidocaine injection at trigger points combined with a physical therapy program would be more effective than either treatment alone in improving pain, function, and quality of life in patients with MPS of the shoulder girdle and cervical region.

The study included 127 patients with neck or shoulder pain for more than 6 weeks and a score above 40 mm on the visual analog scale for pain. Participants were randomized into three groups: physical therapy plus lidocaine injection (PT+LI, n=43), physical therapy alone (PT, n=41), and lidocaine injection alone (LI, n=43). The physical therapy intervention consisted of 12 one-hour sessions, three times per week, for four weeks. Each session included heat application and ultrasound, manual deactivation of trigger points by gradual compression, manual techniques such as deep stretching, and specific stretching and strengthening exercises for the cervical and shoulder girdle muscles.

Lidocaine 0.5% without epinephrine was administered once directly into the trigger points using a 25- or 26-gauge needle. The primary outcome was pain intensity measured by the visual analog scale 30 days after the start of treatment. Secondary outcomes included pain assessment at 3 months, function through specific hand-to-back and hand-to-mouth maneuvers, quality of life by the SF-36 questionnaire, and depressive symptoms by the PHQ-9, evaluated at 1 and 3 months post-treatment. The results showed no statistically significant differences in pain scores between groups at 30 days: PT+LI showed a mean of 40.8 (± 25.3), PT 37.8 (± 21.9), and LI 44.2 (± 24.9), with p > 0.05 for all comparisons.

Similarly, no significant differences were observed in depression scores or in the SF-36 quality-of-life dimensions at any of the follow-up time points. The only significant functional difference was that the PT and PT+LI groups showed better scores on the right upper limb hand-to-back maneuver compared with the LI group alone, both at 1 and 3 months. As for the use of supplemental analgesics, there were no significant differences between groups. Complications were minimal, limited to localized hematomas in 4 patients in the PT+LI group and 2 in the LI group, representing a complication rate of 2.66% for the total injections performed.

These findings suggest that both physical therapy and lidocaine injections are equally effective as individual treatments for MPS, and that the combination does not offer significant additional advantages. Physical therapy showed a slight advantage in improving right upper limb function, which may be clinically relevant for patients with specific functional limitations. From a clinical standpoint, these results are important because they show that different therapeutic approaches may be equally valid, allowing individualization of treatment based on patient preferences, resource availability, and cost-benefit considerations. Lidocaine injections represent a low-cost option that can be repeated when necessary, while physical therapy offers additional functional benefits that may be particularly valuable for long-term rehabilitation.