Sagittal plane balancing in the total knee arthroplasty

Area of Science:

• Orthopedic Surgery
• Biomechanical Engineering
• Medical Device Technology

Background:

• Sagittal plane imbalance in total knee arthroplasty (TKA) can lead to postoperative stiffness or instability.
• Various instrumentation systems exist for TKA, employing different strategies to achieve sagittal plane balance.

Purpose of the Study:

• To review the strengths and weaknesses of different TKA instrumentation systems regarding sagittal plane balance.
• To provide clinicians with system-specific troubleshooting guidelines for intraoperative sagittal plane imbalance.

Main Methods:

• Comparative review of anterior referencing, posterior referencing, and flexion/extension gap systems for TKA.
• Analysis of how femoral size selection impacts sagittal balance in different systems.
• Evaluation of the role of spacer blocks in gap balancing and potential complications.

Main Results:

• Anterior referencing systems: Femoral size impacts flexion gap; size selection is critical for balance.
• Posterior referencing systems: Femoral size affects patellofemoral articulation, not flexion gap.
• Flexion/extension gap systems: Rely on spacers, may not ensure midrange stability, risk malposition or joint line elevation if misused.

Conclusions:

• Understanding system-specific characteristics is essential for achieving optimal sagittal plane balance during TKA.
• Clinicians should be aware of the potential pitfalls associated with each TKA instrumentation system to avoid intraoperative imbalance and subsequent complications.