ISAKOS Congress 2021

2021 ISAKOS Biennial Congress Paper


Greater Postoperative Valgus Loose Gap At 90° Of Flexion Improves Patient Reported Outcome Measurement In Anatomical Bi-Cruciate Retaining Total Knee Arthroplasty

Takao Kaneko, MD,PhD, Tokyo JAPAN
Yuta Mochizuki, MD, Tokyo JAPAN
Masaru Hada, MD, Tokyo JAPAN
Shinya Toyoda, MD, Tokyo JAPAN
Kazutaka Takada, MD, Tokyo JAPAN
Hiroyasu Ikegami, MD, PhD, Prof., Tokyo JAPAN

Department of Orthopedic Surgery, Toho University School of Medicine , Tokyo, JAPAN

FDA Status Cleared


Anatomical bi-cruciate retaining total knee arthroplasty



The purpose of the present study is to measure the intraoperative joint gap using tensor device and pre- and, postoperative variation of coronal stability at 0, 30 and 90° of flexion using stress radiograph and identify whether these factors influence patient reported outcome measurement (PROM).


53 knees with preoperative varus osteoarthritis of the knee were treated with anatomical BCR TKA with oblique 3°angle femorotibial joint line (Journey II XR; Smith& Nephew. Inc. Memphis, TN, USA). The intraoperative joint gap (medial, lateral and varus-valgus) using a tensor device and varus-valgus gap angle were measured using stress radiographs. PROM was also evaluated at 1.5 years postoperatively.


There was no significant difference between pre- and postoperative flexion angle. Intraoperative medial laxity rather than medial tightness from full extension to 140° of flexion angle played an important role in influencing postoperative function of patellofemoral joint. Intraoperative varus laxity at full extension improved postoperative symptom in 2011 Knee Society Score (2011 KSS), while greater postoperative lateral stability at 30 and 90° of flexion with the varus stress test was found to contribute to the patient expectation in 2011 KSS. Greater postoperative valgus laxity at 90° of flexion with the valgus stress test improved the patient expectation and satisfaction in 2011 KSS, stiffness in WOMAC score and FJS-12.


The findings in the present study suggest that the intraoperative joint gap after implantation is not rectangular but trapezoidal gap and greater postoperative varus stability and valgus laxity at 90° of flexion improved patient reported outcome measurement in anatomical BCR TKA.

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