Is limb overcorrection following total knee arthroplasty compromising functional outcome?

Area of Science:

• Orthopedic surgery
• Biomedical engineering

Background:

• Patient dissatisfaction and suboptimal function persist after total knee arthroplasty (TKA).
• Personalized alignment strategies are increasingly explored to enhance TKA outcomes.
• The impact of coronal plane limb alignment on patient satisfaction requires further investigation.

Purpose of the Study:

• To evaluate the effect of unintended limb overcorrection in the coronal plane on patient satisfaction and functional outcomes after TKA.
• To determine if changes in knee phenotype following TKA influence clinical results.

Main Methods:

• A retrospective case-control study compared 37 patients with limb overcorrection (≥2° mechanical HKA opposite to preoperative alignment) to 104 controls (neutral or slight undercorrection).
• Follow-up averaged 68 months, with outcomes assessed using the 2011 Knee Society Score (KSS) and Knee Injury and Osteoarthritis Outcome Score (KOOS).
• Radiographic analysis included component alignment (LDFA, MPTA) and Coronal Plane Alignment of the knee (CPAK) phenotypes.

Main Results:

• The overcorrection group demonstrated superior outcomes in KSS satisfaction and function, total KSS, and all KOOS subcategories and total score compared to the control group.
• Subgroup analyses of mild/severe overcorrection and neutral/undercorrection controls showed consistent findings.
• Alterations in knee phenotype (aHKA, JLO, CPAK) did not correlate with poorer clinical outcomes.

Conclusions:

• Limb overcorrection following TKA does not lead to inferior clinical outcomes or patient satisfaction at midterm follow-up.
• This study did not identify a specific optimal coronal alignment target.
• Coronal alignment may be a less significant predictor of patient satisfaction and function after TKA than previously assumed.