Kinematic TKA using navigation: Surgical technique and initial results.

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Reconstructive Surgery

Background:

• Kinematic alignment in total knee arthroplasty (TKA) aims to improve patient outcomes.
• Previous methods like patient-specific instrumentation are costly, while standard instrumentation lacks intraoperative feedback on resection alignment.

Purpose of the Study:

• To evaluate computer navigation's ability to replicate native knee anatomy during TKA.
• To assess if computer navigation simplifies ligament balancing and improves functional scores post-surgery.

Main Methods:

• Computer navigation was employed for kinematic distal femoral and proximal tibial cuts in 100 TKAs.
• Resections were adjusted if angles fell outside pre-defined safe ranges.
• Pre- and postoperative radiographic measurements (HKA, LDFA, MPTA) and clinical scores (WOMAC, KOOS) were analyzed.

Main Results:

• Postoperative alignment showed no significant change in LDFA (P=0.41) but a significant change in MPTA (P=0.03).
• Significant improvements were observed in WOMAC (P<0.001) and KOOS (P<0.001) scores.
• 5% of knees required additional ligament release, and 2% needed lateral retinacular release for patellar tracking.

Conclusions:

• Computer navigation offers surgeons precise control and feedback during kinematic TKA.
• This technique allows for partial correction of challenging anatomy while preserving ligament isometry.
• Satisfactory improvements in functional outcomes were achieved in the early postoperative period.