Knee phenotypes distribution according to CPAK classification in Turkish population

Area of Science:

• Orthopedics
• Radiology
• Biomedical Engineering

Background:

• Knee phenotypes influence osteoarthritis development and treatment.
• The Crane-King Classification (CPAK) categorizes knee morphology.
• Understanding CPAK distribution in diverse populations is crucial for personalized medicine.

Purpose of the Study:

• To determine the distribution of CPAK knee phenotypes in a Turkish population.
• To compare CPAK classification in healthy knees versus osteoarthritic knees.
• To assess the prevalence of CPAK type V, a target for mechanical alignment strategies.

Main Methods:

• Radiological EOS analysis of 1172 nonarthritic and 571 osteoarthritic knees.
• Knees categorized into 9 CPAK subgroups based on arithmetic hip-knee-ankle (aHKA) angle and joint-line obliquity (JLO).
• Measurements derived from medial proximal tibial angle (MPTA) and lateral distal femoral angle (LDFA) using Sectra workstation.

Main Results:

• CPAK type IV was most common in nonarthritic knees (46.67%) and CPAK type I in osteoarthritic knees (20.7%).
• Prevalence of CPAK type V was 7.7% in nonarthritic and 8.4% in osteoarthritic groups.
• Significant differences in aHKA and JLO means observed between nonarthritic and osteoarthritic groups.

Conclusions:

• CPAK type IV and I are the predominant knee phenotypes in the Turkish population.
• CPAK type V, relevant for mechanical alignment, shows low prevalence in both healthy and osteoarthritic knees.
• Findings highlight population-specific variations in knee morphology and CPAK distribution.