Methods of alignment in total knee arthroplasty, systematic review

Area of Science:

• Orthopedic Surgery
• Biomechanical Engineering
• Clinical Outcomes Research

Background:

• Total knee arthroplasty (TKA) is a common procedure, yet patient satisfaction remains suboptimal in approximately 20% of cases.
• Mechanical alignment (MA) is the predominant surgical technique, but emerging methods aim to replicate the knee's native alignment for potentially better results.

Purpose of the Study:

• To systematically review clinical trials and observational studies comparing alignment techniques in TKA.
• To evaluate clinical and radiological outcomes of kinematic, anatomic, and functional alignment against MA.

Main Methods:

• Systematic review of studies assessing patient-reported outcome measures (PROMs) including WOMAC, OKS, KSS, KOOS, and FJS.
• Radiological assessment of angles like HKA, mLDFA, MPTA, JLOA, femoral rotation, and tibial slope.
• Evaluation of range of motion (ROM) and complication rates across different alignment groups.

Main Results:

• Kinematic and functional alignment demonstrated a trend towards improved PROMs compared to MA.
• No significant differences in complication rates were observed between the alignment groups.
• Anatomic alignment showed no significant differences in outcomes compared to MA, with some inconsistencies noted across studies.

Conclusions:

• Kinematic alignment presents a viable alternative to MA in TKA, potentially offering equivalent or slightly superior outcomes.
• The observed differences in outcomes between alignment methods may not fully account for the high rate of patient dissatisfaction.
• Future research should consider broader patient inclusion criteria and investigate patient knee phenotypes to identify optimal alignment strategies for specific patient groups.