Comparative Study of Pinless Navigation System versus Conventional Instrumentation in Total Knee Arthroplasty

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Medical Technology Evaluation

Background:

• Total knee arthroplasty (TKA) aims for optimal component placement and neutral mechanical axis alignment.
• Computerized navigation systems are employed to achieve these goals in TKA.
• This study compares pinless navigation (PNA) TKA with conventional instrumented (CIN) TKA.

Purpose of the Study:

• To compare functional and radiological outcomes of PNA-TKA using iAssist versus CIN-TKA.
• To evaluate component positioning and mechanical axis alignment in both TKA techniques.
• To assess short-term functional outcomes and complication rates.

Main Methods:

• Retrospective study of 100 TKAs performed by a single surgeon over 2 years.
• Analysis of postoperative weight-bearing radiographs and scanograms for alignment and positioning.
• Functional assessment using Oxford knee scoring.

Main Results:

• No significant difference in mean mechanical axis alignment or component positioning between PNA-TKA and CIN-TKA groups.
• PNA-TKA group showed a trend towards fewer mechanical axis outliers, but not statistically significant.
• Surgical time was significantly longer for PNA-TKA (11 minutes increase).
• No complications were reported in the PNA-TKA group, versus 6.89% in the CIN-TKA group.

Conclusions:

• Conventional instrumentation achieves accurate TKA alignment and positioning, questioning the added cost of PNA systems.
• Short-term functional outcomes are comparable between PNA-TKA and CIN-TKA.
• Increased surgical time with PNA-TKA may be due to surgeon unfamiliarity with the system.