Neutral mechanical alignment: a requirement for successful TKA: opposes.

Area of Science:

• Orthopedics
• Biomechanics
• Human Anatomy

Background:

• Neutral knee alignment is often considered normal, but evidence suggests it may not be for all patients.
• Constitutional varus, a long-standing varus alignment since skeletal maturity, presents a challenge to traditional treatment goals.
• Restoring neutral alignment may be unnatural and detrimental for individuals with constitutional varus.

Purpose of the Study:

• To investigate the development and prevalence of constitutional varus.
• To identify factors influencing the development of constitutional varus, including activity levels during growth.
• To determine the incidence of constitutional varus in young adults.

Main Methods:

• Observational studies analyzing a cohort of 800 young patients to assess the impact of activity on lower-leg alignment during growth.
• Cross-sectional analysis of 250 asymptomatic adults (aged 20-27) to determine the incidence of constitutional varus.
• Measurement of natural mechanical alignment in degrees of varus or valgus.

Main Results:

• Constitutional varus, defined as natural mechanical alignment of >=3° varus, was found in 32% of adult men and 17% of adult women.
• Increased sports activity during growth was associated with the development of constitutional varus.
• Constitutional varus became apparent during the growth spurt, suggesting a developmental etiology possibly related to Hueter-Volkmann's law.

Conclusions:

• A significant portion of the population exhibits constitutional varus, representing a natural lower-leg alignment.
• Restoring neutral alignment in patients with constitutional varus may not be the optimal or natural treatment approach.
• Understanding constitutional varus is crucial for personalized orthopedic treatment strategies.