TAIPEI (Taiwan News) — Chang Gung Memorial Hospital Linkou successfully performed Taiwan's first total temporomandibular joint replacement surgery, restoring a patient's facial symmetry and enabling normal chewing, the hospital announced Tuesday.

The temporomandibular joints (TMJs) connect the lower jaw to the skull and are among the body’s most complex joints. They enable a range of jaw movements, including up and down, side to side, and forward and back, according to Johns Hopkins Medicine.

Proper alignment of these structures is essential for smooth actions like chewing, talking, yawning, and swallowing. Misalignment or lack of synchronized movement within these structures can lead to various TMJ disorders.

The 34-year-old patient surnamed Yeh (葉) suffered comminuted fractures in both TMJs during a car accident five years ago. This caused facial deformity, misaligned teeth, and a receding jaw.

Yeh struggled to eat properly, resulting in significant weight loss, and had difficulty speaking, affecting his daily social interactions. Changes in his appearance also caused severe self-esteem issues, per CNA.

Liao Han-Tsung (廖漢聰), who treated Yeh, said the hospital obtained special approval from the health ministry to import the device needed for his treatment. Using 3D printing technology, cutting guides, orthognathic surgery guides, occlusal plates, and placement guides were created for the artificial joint.

A small incision was made in front of the patient's ear to remove the damaged TMJ portions. A suitable artificial joint was then implanted, completing the repair.

Three months after the surgery, Liao said, the patient’s face regained symmetry, and his mouth-opening function reached 4.5 to 5 cm, enabling him to chew hard foods. A five-year follow-up revealed no signs of infection or joint rejection, with the wound healing well.

Liao noted that while TMJ replacement surgery has a 20 to 30-year history internationally, Taiwan previously lacked imported products from distributors. Common joint replacement surgeries typically involve the knee or hip.

In the past, reconstruction often relied on autologous rib grafts, which use a patient's own rib cartilage for facial reconstruction or support. The surgery has drawbacks such as potential absorption of the grafted rib and unpredictable post-operative function.

The new artificial TMJ implant, approved by Taiwan's Health Ministry, is designed for patients with trauma, degenerative diseases, fibrosis, joint stiffness, or congenital defects, Liao said. He added that it offers more treatment options for temporomandibular joint disorder (TMD).

TMJ issues often arise from trauma, degeneration, infections, or mechanical problems, causing pain, restricted movement, joint noises, headaches, and ear pain. About 20% to 25% of Taiwan's population has TMD, according to the National Health Insurance Administration.