Evaluation of limb alignment, component positioning, and function in primary total knee arthroplasty using a pinless...

Area of Science:

• Orthopedic Surgery
• Medical Technology
• Biomechanical Engineering

Background:

• Total knee arthroplasty (TKA) aims to restore knee function and alignment.
• Conventional alignment methods can have limitations in achieving optimal limb positioning.
• Image-free navigation systems offer potential advantages in surgical accuracy.

Purpose of the Study:

• To evaluate the component positioning, limb alignment, and early functional range of motion using a pinless, image-free computer-assisted navigation system.
• To compare the outcomes of the pinless navigation system with conventional intramedullary alignment techniques in TKA.

Main Methods:

• A comparative study involving 72 patients undergoing cemented TKA.
• Patients were divided into two groups: pinless navigation (40 knees) and conventional intramedullary alignment (33 knees).
• Preoperative and postoperative radiographs assessed coronal and sagittal alignment; early range of motion was evaluated postoperatively.

Main Results:

• No significant differences were found in individual component alignment or early functional range of motion between the groups.
• The pinless navigation group achieved the target 4-7 degrees of valgus tibiofemoral alignment in 65% of cases, compared to 39% in the conventional group (p < 0.03).
• Tourniquet time was longer in the pinless navigation group (mean 71.9 min) versus the conventional group (mean 59.5 min) (p < 0.0001).

Conclusions:

• The pinless navigation technique demonstrated superior coronal anatomic alignment in TKA.
• This system offers an alternative to traditional methods, avoiding complications associated with reference pins or guides.
• Further research may explore optimizing operative time with navigation systems.