Volumetric Quantification of Articular Depression Adds Prognostic Value to Three-Dimensional Gap Area Assessment in...

Three-dimensional (3D) assessment of tibial plateau fractures has traditionally relied on surface-based parameters such as gap area, which may not fully reflect the severity of articular injury. This study investigated whether volumetric quantification of articular depression provides independent prognostic information beyond conventional surface-based 3D measurements in Schatzker type III tibial plateau fractures. A retrospective analysis was performed on 38 patients with isolated Schatzker type III lateral tibial plateau fractures treated operatively between 2017 and 2023. Preoperative computed tomography scans were used to generate 3D reconstructions. Three-dimensional gap area, depression surface area, and depression volume were quantified. Patients with a postoperative articular step-off ≥ 2 mm were excluded. Radiological outcomes were graded using the Kellgren-Lawrence (KL) classification, and functional outcomes were assessed using the KOOS. Mean depression volume was 5650 ± 2459 mm3. Depression volume showed only moderate correlation with depression surface area (r = 0.42, p = 0.01) and 3D gap area (r = 0.41, p = 0.01). Patients with depression volumes ≥ 6000 mm3 demonstrated significantly lower KOOS compared with those with volumes < 6000 mm3 (p = 0.01). In multivariable logistic regression analyses adjusted for demographic variables and surface-based fracture parameters, depression volume remained significantly associated with poor radiological outcome (KL ≥ 2; odds ratio 2.34 per 1000 mm3 increase, p = 0.02). Volumetric quantification of articular depression provides clinically relevant prognostic information beyond surface-based 3D measurements and may improve risk stratification in Schatzker type III tibial plateau fractures. LEVEL OF EVIDENCE: Prognostic Level III.