Unilateral condylar hyperplasia (UCH), marked by progressive condylar growth, occurs between ages 11–30 with unclear etiology. This retrospective study aims to clarify the clinical, radiographic, and demographic features of UCH to improve its diagnosis and treatment.

Data for all patients included in this study were retrieved from the archive. Inclusion criteria were the diagnosis of UCH supported by a positive bone scan above 10% of condylar uptake in SPECT/CT, the patient's history of progressive facial asymmetry, symptoms confirmed by the orthodontist during follow-up, and clinical and radiological evaluation. Demographic characteristics, along with volumetric and linear measurements, were statistically evaluated.

Forty-one patients were included in this study with 70.73% female predominance. Patients were classified as transverse and vertical type condylar hyperplasia (CH) according to their prominent asymmetry characteristics. Eighteen patients were classified as vertical type CH and 23 patients were classified as transverse type CH. Twenty had left-side condylar overgrowth, and 21 had right-side overgrowth. Condylar volume difference was significantly higher in vertical type CH patients compared to transverse type CH (p = 0.004). No correlation was found between growth rate (bone scan uptake ratio) and condylar volume difference in patients with vertical type and transverse type CH patients (p = 0.205).

Particularly in cases that exhibit a pronounced vertical growth tendency, volumetric and linear measurements can guide the timing and treatment planning process.