Notching is less, if femoral component sagittal positioning is planned perpendicular to distal femur anterior cortex axis, in navigated TKA

• Published in: Knee Surgery and Related Research, 33(0) Vol. 33; no. 1; p. 46
• Main Authors: Kanna, Raj, Ravichandran, Chandramohan, Shetty, Gautam M
• Format: Journal Article
• Language: English
• Published: England BioMed Central 24-12-2021; BMC; 대한슬관절학회
• Subjects: Anterior femoral bowing; Anterior femoral notching; Computer-assisted knee replacement; Femoral component positioning; Sagittal alignment in TKA; 정형외과학; Computer-assisted knee replacement; Femoral component positioning; Anterior femoral notching; Anterior femoral bowing; Sagittal alignment in TKA
• ISSN: 2234-0726; 2234-2451; 1225-1623; 2234-2451
• DOI: 10.1186/s43019-021-00129-9

In navigated TKA, the risk of notching is high if femoral component sagittal positioning is planned perpendicular to the sagittal mechanical axis of femur (SMX). We intended to determine if, by opting to place the femoral component perpendicular to distal femur anterior cortex axis (DCX), notching can be reduced in navigated TKA.
We studied 171 patients who underwent simultaneous bilateral computer-assisted TKA. Femoral component sagittal positioning was planned perpendicular to SMX in one knee (Femur Anterior Bowing Registration Disabled, i.e. FBRD group) and perpendicular to DCX in the opposite knee (Femur Anterior Bowing Registration Enabled, i.e. FBRE group). Incidence and depth of notching were recorded in both groups. For FBRE knees, distal anterior cortex angle (DCA), which is the angle between SMX and DCX, was calculated by the computer.
Incidence and mean depth of notching was less (p = 0.0007 and 0.009) in FBRE versus FBRD group, i.e. 7% versus 19.9% and 0.98 mm versus 1.53 mm, respectively. Notching was very high (61.8%) in FBRD limbs when the anterior bowing was severe (DCA > 3°) in the contralateral (FBRE) limbs.
Notching was less when femoral component sagittal positioning was planned perpendicular to DCX, in navigated TKA.
Therapeutic level II.