Tibial component rotation in total knee arthroplasty

Area of Science:

• Orthopedic Surgery
• Biomechanical Engineering
• Medical Device Technology

Background:

• Total knee arthroplasty (TKA) commonly utilizes range of motion (ROM) and tibial tubercle landmark (TTL) techniques for tibial component rotational alignment.
• Understanding intra-operative rotational differences between these techniques is crucial for surgical accuracy.

Purpose of the Study:

• To assess intra-operative differences in tibial rotation positioning during computer-navigated primary TKA using ROM versus TTL techniques.
• To evaluate the repeatability of the ROM technique in tibial component alignment.

Main Methods:

• A prospective, observational study involving 20 patients undergoing primary TKA.
• Computer navigation was employed to measure tibial rotation differences between ROM and TTL techniques.
• Antero-posterior axis of the cut proximal tibia was evaluated without postoperative clinical assessment.

Main Results:

• The ROM technique demonstrated high repeatability, with an interclass correlation coefficient (ICC2) of 0.84.
• A statistically significant average difference of 4.56 degrees external rotation was observed with the ROM technique compared to the TTL technique.
• Greater intra-operative flexion and pre-operative mechanical axis deviations correlated positively with the magnitude of rotational difference.

Conclusions:

• A significant rotational positioning difference exists between the ROM and TTL techniques in TKA.
• Surgeons must recognize this discrepancy, as it is influenced by factors like maximum flexion and mechanical axis alignment.
• Awareness of these differences can optimize tibial component placement and potentially improve TKA outcomes.