Mid-sulcus line predictive guide for tibial mechanical axis during TKA

The study was conducted at Department of Orthopaedics, Arogyam Superspeciality Hospital, Nagpur, India. The article has been published in ‘The Knee’ journal. A total of 322 patients undergoing primary TKA (excluding previously operated limbs and limbs with extra-articular deformities of tibia or femur) using CANS were included in the study. After resecting ACL, the mid-sulcus line was drawn with a cautery tip. The authors hypothesized that if tibial cut was made perpendicular to the mid-sulcus line, coronal alignment of the tibial component would be along the neutral mechanical axis. This was evaluated intra-operatively with the help of CANS.

Key findings of the study were:

• A total of 279 patients were found to have pre-operative varus alignment with mean deformity of 5.60 (range, 0.5–260). Forty-three patients were found to have pre-operative valgus alignment with mean deformity of 5.20 (range, 0.5–180).

• Of 322 knees, identification of the ‘mid-sulcus line’ was possible in 312 knees.

• The mean angle between the tibial alignment defined by mid-sulcus line and the neutral mechanical axis was found to be 0.450 (range, 0–1.50) (P < 0.05).

• In all of the 312 knees, the tibial alignment defined by mid-sulcus line was found to be within 30 of the neutral mechanical axis (confidence interval: 0.4100, 0.4910).

Further reading:

Is mid-sulcus line a predictive guide for tibial mechanical axis during total knee arthroplasty? A. Umre, O. Wakde and R. Meghare The Knee 41 (2023) 373–379 https://doi.org/10.1016/j.knee.2023.02.003