A Useful Radiologic Method for Preoperative Joint-line Determination in Revision Total Knee Arthroplasty

Abstract

Intraoperative joint-line determination during revision TKA is difficult and no method exists to plan the position preoperatively. Two questions need to be answered: to which extent does the joint line differ from its anatomic position after revision TKA if it has only been determined intraoperatively, and can the joint line be calculated preoperatively based on the transepicondylar width. Of 22 consecutive patients with complete preoperative (before and after primary TKA) and postoperative (after revision TKA) radiograph documentation, the joint-line position was measured on plane radiographs using the medial epicondyle as a reference. On another set of 45 consecutive patients with no knee disorders other than meniscal lesions, the transepicondylar axis width (TEAW) and the perpendicular distance from the medial and lateral epicondyles to the joint line were measured twice by two independent observers on plane AP radiographs of the knee. Significant joint-line alterations were observed after primary and revision TKA, implicating that a method for preoperative planning is needed. Because a linear correlation between the TEAW and the perpendicular distance from the epicondyles to the joint-line tangent was found, the ratio is useful to calculate the true joint-line position from the TEAW before revision TKA.

Revision knee surgery techniques

“…4). 24 In cases of scarring over the medial epicondylar sulcus, a metal ruler may be passed under the medial collateral ligament until it reaches the ligamentous origin to help establish the joint line. 2 …”

The intercondylar notch ceiling: an accurate reference for distal femoral resection in total knee arthroplasty for severely degenerated varus knees

“…A previous study by Servien et al [25] showed that the average distance from the femoral epicondyles to the joint line was 23 mm on the lateral side and 28 mm on the medial side. In another study, Figgie et al [6] reported that the joint line was 3.1 cm below the medial femoral epicondyle and 2.5 cm below the lateral femoral epicondyle, which was further corroborated by Romero et al [23]. Nevertheless, other studies have also demonstrated that selection of the epicondyles as a reference could produce results with great variance [3,28,30].…”

“Meniscal” scar as a landmark for the joint line in revision total knee replacement

“…Mid-flexion instability is caused by tight posterior structures that provide stability in extension and at 90 degrees of flexion[6]. A recent review of studies demonstrated elevation of the joint line in 79% of revision TKAs by 3-13 mm[2,5,7]. Singerman et al[11] demonstrated that raising or lowering the joint line in revision TKA by more than 8 mm resulted in a decreased range of motion and lower modified Mayo Clinic knee scores.…”