Abstract: Objective: To report the combined orthodontic and joint treatment of a patient with skeletal mandibular deviation caused by active unilateral condylar hyperplasia(UCH). Diagnosis and Treatment: A 20-year-old female presented with right UCH and mandibular deviation; her right mandibular ramus was approximately 11 mm longer than the left. A ‘joint surgery-preceded’ approach was implemented, starting with a right proportional condylectomy to block excessive growth and correct vertical skeletal asymmetry. This was immediately followed by fixed orthodontics and temporary anchorage devices (TADs) for occlusal and midline adjustments. Results: After a 29-month treatment duration, facial asymmetry was significantly improved, midlines were aligned, and a Class I relationship with normal overbite and overjet was established. The temporomandibular joint functioned well without clicking or pain. Conclusions: Proportional condylectomy combined with a ‘surgery-first’ orthodontic strategy effectively halts deformity progression, avoids the presurgical decompensation process, and simultaneously restores facial aesthetics, occlusal function, and joint health.

Key words: unilateral condylar hyperplasia, combined orthodontic-orthognathic treatment, unilateral proportional condylectomy, joint surgery-preceded approach, mandibular deviation