Orthopaedic Journal of Sports Medicine
Coronal Plane Alignment of the Knee Classification in the Brazilian Population: A Radiographic Analysis of Patients With Primary Knee Osteoarthritis Undergoing Total Knee Arthroplasty
By F.A.C. Menegassi, R.E. De Paula, D.P. Da Motta and 3 others.
Abstract
Objectives
To identify the incidence and distribution of lower limb deformities according to the Coronal Plane Alignment of the Knee (CPAK) classification in patients with primary knee osteoarthritis treated with total knee arthroplasty (TKA) at a national reference center.
Methods
This retrospective cohort study evaluated 476 knees of patients who underwent primary TKA between 2023 and 2025. Preoperative standing anteroposterior radiographs including the hip, knee, and ankle joints were analyzed. Angular parameters were measured according to Paley’s method using dedicated software (PeekMed), including mechanical lateral distal femoral angle, mechanical medial proximal tibial angle, hip–knee–ankle (HKA) angle, and joint line obliquity (JLO). Patients were classified according to the CPAK system. Only patients with nontraumatic primary osteoarthritis and adequate radiographs were included.