There is a significant prevalence of temporomandibular joint (TMJ) disorders, estimated at 34% according to various sources. Given that this condition often leads to a reduced quality of life and disability, there is a pressing need to develop and implement effective treatment methods. Arthrocentesis, along with the injection of pharmacological agents—particularly platelet-rich plasma—into the joint cavity, is a recognized treatment for TMJ osteoarthritis. Recently, a third generation of platelet concentrates has been developed, which is an evolutionary advancement of the platelet-rich plasma technique. This study involved 60 patients, equally divided into control and experimental groups. The control group was treated with arthrocentesis for TMJ osteoarthritis, while the experimental group received arthrocentesis combined with intra-articular injections of concentrated growth factor. The effectiveness of the treatments was evaluated using the visual analogue scale (VAS) for pain and measuring maximum mouth opening. The study results showed a 74.22% reduction in VAS scores in the control group and a 79.87% reduction in the experimental group (p < 0.001). Maximum mouth opening increased by 17.84% in the control group and by 20.53% in the experimental group (p < 0.001). Both treatment methods demonstrated significant clinical efficacy (p < 0.001). In our opinion, the use of arthrocentesis with concentrated growth factor injections for the treatment of TMJ osteoarthritis is clinically justified and more effective than arthrocentesis alone.