Gap balancing versus measured resection technique using a mobile-bearing prosthesis in computer-assisted surgery.

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Surgical Navigation

Background:

• Surgical navigation systems enhance implant accuracy and record intra-operative joint data.
• Two primary strategies exist for femoral component alignment: measured gap resection and gap balancing.
• Mobile-bearing (MB) knee arthroplasty is a common procedure where alignment techniques are critical.

Purpose of the Study:

• To compare navigated gap-balancing technique (GG) versus computer-assisted measured resection technique (MG) in knee arthroplasty.
• To analyze the impact of these techniques on joint line maintenance, axial limb restoration, and component positioning.
• To evaluate the effect on post-operative outcomes and identify outliers.

Main Methods:

• A comparative study of 67 patients undergoing knee arthroplasty with mobile-bearing prostheses.
• Group 1 (GG, 31 patients): Navigated gap-balancing technique.
• Group 2 (MG, 36 patients): Computer-assisted measured resection technique.

Main Results:

• No statistically significant difference in mechanical axis or prosthetic positioning outliers between GG and MG (P=0.56).
• The gap-balancing technique (GG) demonstrated a statistically significant alteration in post-operative joint line position compared to the measured resection technique (MG) (P=0.036).
• Mean joint line elevation was 4.09 mm for GG and 3.50 mm for MG.

Conclusions:

• While both navigated techniques achieve comparable limb alignment and component positioning, the gap-balancing method significantly alters joint line elevation.
• Measured resection technique may offer more predictable joint line restoration in navigated knee arthroplasty.
• Further research is warranted to optimize navigated techniques for precise joint line management.