The effectiveness of guided botulinum toxin “A” injection to the masticatory muscles in the management of condylar and sub condylar fractures: a randomized controlled clinical trial

Objective To evaluate the effectiveness of ultrasound guided injection of botulinum toxin A into the muscles of mastication; the masseter, temporalis and the lateral pterygoid, in a closed reduction approach of condylar and sub-condylar fractures, to optimize fracture reduction, reduce the length of intermaxillary fixation (IMF) and to facilitate postoperative functional recovery. Materials and methods Sixteen medically healthy patients aged 18–35 years, presenting with unilateral subcondylar fracture were randomly assigned into two groups. The randomized controlled clinical trial was completed after recruitment, intervention, and follow up of all participants. The Study group (A) underwent an intervention involving ultrasound-guided Botulinum Toxin (BTX) injection into the Lateral Pterygoid Muscle (LPM), the Temporalis and the Masseter muscles, followed by the closed reduction treatment of the fracture, compared to the control group (B) that underwent conventional treatment method; the closed reduction approach without any BTX injections. Results Pain scores were significantly lower in the study group (A), especially after the botulinum toxin injection ( p < 0.001*) which subsequently led to a significantly shorter operation time ( p < 0.001*) in the study group compared with the control group (B). Following surgery, mouth opening improved significantly over time in both groups ( p < 0.001*); however, the study group showed significantly greater improvement at 14 days (31.44 ± 2.72 mm versus 14.46 ± 3.24 mm, in the control group; p < 0.001*) and at 6 weeks postoperatively, (38.02 ± 3.26 mm versus 17.88 ± 4.49 mm; p < 0.001*) respectively. Regarding structural outcomes, patients in the study group demonstrated significantly better postoperative reduction accuracy, with lower angulation values ( p < 0.02*) immediately postoperative and at 6 months compared with the control group. Finally, bone density at the fracture line increased significantly over time in both groups ( p < 0.001*), however no significant difference was noted comparing both groups together ( p = 0.37). Conclusions The addition of guided botulinum toxin A to the closed reduction protocols for subcondylar fractures significantly reduces postoperative pain and operative duration while optimizing alignment accuracy and functional mobility recovery. Given that bone healing remains uncompromised, this approach serves as an efficient, reliable alternative that directly improves patient outcomes. Trial status Completed. Trial registration The study was initially designed and ethically approved as an institutional clinical investigation. Trial registration was subsequently undertaken upon recognition of the importance of public trial registration in promoting transparency and facilitating dissemination of the study findings. The study protocol, eligibility criteria, outcome measures, and statistical analysis plan were defined prior to patient enrollment and remained unchanged following registration. The study was retrospectively registered with ClinicalTrials.gov on January 28, 2026 (NCT07374341).