Is Static Alignment a Good Predictor of Dynamic Alignment after Total Knee Arthroplasty?

Area of Science:

• Orthopedic Surgery
• Biomechanics
• Gait Analysis

Background:

• Total knee arthroplasty (TKA) is the primary treatment for end-stage knee osteoarthritis (OA).
• Traditionally, neutral lower limb alignment is believed to predict prosthesis longevity, but recent studies question this assumption.
• The role of dynamic mechanical alignment versus static alignment in prosthesis survival requires further investigation.

Purpose of the Study:

• To investigate the relationship between static lower limb alignment and postoperative gait parameters after TKA.
• To determine if static alignment predicts dynamic mechanical alignment and knee adduction moment (KAM) post-TKA.
• To explore the predictive value of dynamic alignment on KAM after TKA.

Main Methods:

• Eighty-seven patients with knee OA underwent 3D gait analysis before and six months after TKA.
• Patients were categorized into neutral, varus, or valgus static alignment groups based on postoperative X-rays.
• Statistical analyses included linear regression to assess alignment correlations and ANOVA to compare gait parameters.

Main Results:

• No significant differences in gait parameters were observed among the static alignment groups six months post-TKA.
• Post-TKA, static alignment did not correlate with dynamic alignment or KAM, unlike pre-TKA findings.
• A significant linear correlation was found between dynamic alignment and KAM both before and after TKA.

Conclusions:

• Postoperative static lower limb alignment does not significantly influence gait function after TKA.
• Static alignment is not a reliable predictor of dynamic alignment or KAM six months after TKA.
• Dynamic alignment is a better predictor of KAM, a potential factor influencing prosthesis lifespan.