Precision freehand sculpting for unicondylar knee replacement: design and experimental validation

Area of Science:

• Orthopedic Surgery
• Robotic Surgery
• Biomedical Engineering

Background:

• Precision freehand sculpting (PFS) is a semi-active robotic technology for bone shaping.
• It operates within a surgical navigation framework and offers dual control modes: cutting bur exposure and cutting bur speed.
• Evaluating PFS for femoral bone preparation in unicondylar knee replacement (UKR) is crucial for advancing orthopedic procedures.

Purpose of the Study:

• To assess the performance of PFS in preparing the femoral bone surface for unicondylar knee replacement (UKR).
• To evaluate the accuracy of implant fit and the efficiency of the surgical procedure using PFS technology.

Main Methods:

• The study involved preparing a synthetic bone for UKR using PFS with a modified commercial implant for precise measurement.
• Distal and anterior-distal facets were prepared using a 5 mm cylindrical bur with exposure control.
• Posterior facet and post holes were prepared using a 6-mm spherical bur with speed control by three users on five specimens each.

Main Results:

• The average combined time for the first two cuts was 4 minutes and 35 seconds.
• The average time for the posterior cut was 3 minutes and 26 seconds.
• The mean distance from the planned implant position was 0.54 mm (SD 0.23 mm), with an average angular difference of 1.08° (SD 0.53°).

Conclusions:

• Precision freehand sculpting (PFS) demonstrates high accuracy in preparing the femoral bone for unicondylar knee replacement.
• The robotic technology shows promising results for achieving excellent implant fit, with minimal deviation from the planned position.
• PFS offers an efficient and accurate method for bone preparation in knee replacement surgeries.