Is the Medial Wall of the Intercondylar Notch Useful for Tibial Rotational Reference in Unicompartmental Knee Arthroplasty?

Abstract

Background It is difficult to implant components in the correct rotational position in the narrow operating field in a unicompartmental knee arthroplasty. Although no rotational reference has been confirmed for unicompartmental knee arthroplasty, the AP axis of the tibia may serve as a reference for unicompartmental knee arthroplasty and TKA. However, it is difficult to identify the AP axis during unicompartmental knee arthroplasty, especially with the tibia first-cut technique. Questions/purposes We explored whether the medial wall of the intercondylar notch could be useful for the tibial rotational reference as an alternative to the AP axis in unicompartmental knee arthroplasty. Methods We scanned the knees of 24 healthy Asian patients (45 knees) at a flexion angle of 908 using open MRI, then measured the angle between the AP axis and the medial wall of the notch. We determined whether the origins of the ACL and PCL were located lateral to the line on the medial wall of the notch and whether the mediolateral dimension of the bone cut surface of the medial tibial plateau was wide enough relative to the AP dimension to use the commercially available unicompartmental knee arthroplasty tibial components when the tibia was cut parallel to the medial wall of the notch.Results At 908 flexion the medial wall of the notch was externally rotated 0.18 ± 4.48 relative to the AP axis. In all knees, the ACL and PCL were located lateral to the line on the medial wall of the notch. The mediolateral dimension of the bone cut surface was wide enough to use the commercially available tibial components. Conclusions At 908 flexion the medial wall of the intercondylar notch is almost parallel to the AP axis of the tibia at and we believe a reasonable candidate for a rotational reference of tibial placement in unicompartmental knee arthroplasty. This landmark would need to be confirmed in other populations and in patients with osteoarthritis.

Correction of coronal alignment correlates with reconstruction of joint height in unicompartmental knee arthroplasty

“…The rotational alignment of the tibia was adjusted to be parallel to the medial wall of the intercondylar notch in 90° of flexion. 16 The depth of resection for the proximal tibia was determined according to an intra-operative joint laxity test in order that a 9 mm extension gap would be obtained after the resection of the proximal tibia. After the resection of the proximal tibia, the cutting alignment and the gaps in both of extension and flexion were assessed.…”

Feasibility of a Novel Tibial Sighting Device Combined with Intramedullary Femoral Localisation on the Rotational Alignment of the Tibial Component for Oxford Unicompartmental Knee Arthroplasty

“…Akagi et al suggested that the line between the mid-point of the posterior cruciate ligament (PCL) and the medial edge of the patellar tendon could be used as APL for total knee arthroplasty [8][9][10]. The rotational alignment of the tibial component during UKA may also refer to APL used by total knee arthroplasty [1]. However, it can be di cult to identify the tibial APL in a modern mini-incision UKA because the PCL is barely visible or accessible in the small operating eld.…”

“…Many scholars have proposed methods to ensure a perfect rotational alignment. Kawahara et al stated that at a 90° exion, the medial wall of the intercondylar notch is nearly parallel to the anteroposterior (AP) axis of the tibia in normal healthy knees, which is a reasonable candidate for a rotational reference of tibial placement in UKA [1]. However, that landmark should be con rmed in more populations and in patients with osteoarthritis.…”

“…However, these methods have evident shortcomings in the rotational alignment of the tibial component, mainly because of the noticeable displacement of the preoperative body surface markers after disinfection, towel laying, and anti-bacterial lm sticking [5]. Moreover, identifying the AP axis and implanting components in the correct rotational position in a narrow operating eld during UKA is di cult, especially when employing the tibia rst-cut technique [1]. Therefore, we invented a novel tibial sighting device and explored whether combining it with intramedullary femoral localisation could be feasible for the rotational alignment of the tibial component for the OUKA.…”

“…Rotational alignment of the tibial component is important in unicompartmental knee arthroplasty (UKA) [1]. The trans-epicondylar axis (TEA) is the line from the medial epicondylar sulcus and the highest point of the femoral external epicondyle, and is recognised as the rotational axis when the knee joint is extended and exed [2].…”