Anterior tibial curved cortex is a reliable landmark for tibial rotational alignment in total knee arthroplasty.
BACKGROUND
Rotational alignment of the tibial component is important for long-term success of total knee arthroplasty (TKA). This study aimed to compare five axes in normal and osteoarthritic (OA) knees to determine a reliable landmark for tibial rotational alignment in TKA.


METHODS
One hundred twenty patients with OA knees and 40 with normal knees were included. The angle between a line perpendicular to the surgical transepicondylar axis and each of five axes were measured on preoperative computed tomography. The five axes were as follows: a line from the center of the posterior cruciate ligament (PCL) to the medial border of the patellar tendon (PCL-PT), medial border of the tibial tuberosity (PCL-TT1), medial one-third of the tibial tuberosity (PCL-TT2), and apex of the tibial tuberosity (PCL-TT3), as well as the anteroposterior axis of the tibial prosthesis along the anterior tibial curved cortex (ATCC).


RESULTS
For all five axes tested, the mean angles were smaller in OA knees than in normal knees. In normal knees, the angle of the ATCC axis had the smallest mean value and narrowest range (1.6° ± 2.8°; range, -1.7°-7.7°). In OA knees, the mean angle of the ATCC axis (0.8° ± 2.7°; range, -7.9°-9.2°) was larger than that of the PCL-TT1 axis (0.3° ± 5.5°; range, -19.7°-10.6°) (P = 0.461), while the angle of the ATCC axis had the smallest SD and narrowest range.


CONCLUSION
The ATCC was found to be the most reliable and useful anatomical landmark for tibial rotational alignment in TKA.
['Kim|Joong Il|JI|', 'Jang|Jak|J|', 'Lee|Ki Woong|KW|', 'Han|Hyuk Soo|HS|', 'Lee|Sahnghoon|S|', 'Lee|Myung Chul|MC|http://orcid.org/0000-0002-8150-1573']
D000328:Adult D000368:Aged D059925:Anatomic Landmarks D019645:Arthroplasty, Replacement, Knee D005260:Female D006801:Humans D007719:Knee Joint D007720:Knee Prosthesis D008297:Male D008875:Middle Aged D020370:Osteoarthritis, Knee D017847:Patellar Ligament D016119:Posterior Cruciate Ligament D011300:Preoperative Care D016059:Range of Motion, Articular D012399:Rotation D013977:Tibia D014057:Tomography, X-Ray Computed
Anterior tibial curved cortex Rotational alignment Total knee arthroplasty Anatomical landmark Tibial component rotation