Appropriate flexion gap evaluation for fine-tuning of medial stabilizing technique in JOURNEY II bicruciate stabilized total knee arthroplasty

Successful total knee arthroplasty (TKA) relies on proper ligament balancing with a focus on medial stability. Intra-operative evaluation of the medial flexion gap must account for the relative femur–tibia positioning after implant placement. This study investigated whether intra-operative fine-tuning of the medial gap, enabled by a simple, reproducible spacer block for precise flexion gap measurement, could achieve consistent medial gap matching in both extension and flexion. Forty-seven patients (9 men, 38 women) with knee osteoarthritis underwent JOURNEY II bicruciate stabilized TKA. A spacer block simulating post-cam engagement was designed to accurately assess the medial flexion gap. Intra-operative fine-tuning of the medial flexion gap was performed using spacer blocks and a stepless femoral cutting guide. Gaps were measured during the component trial using a tension device and at 1 year post-operatively via stress radiographs. Initially, 29% of knees exhibited a flexion–extension gap difference ≥2 ​mm after posterior cruciate ligament resection and tibial osteotomy. Spacer block fine-tuning reduced this to 8% and this improvement persisted at 1 year. At 4 years follow-up, Knee Society Scores were favorable, with significant gains in extension and flexion angles. The developed spacer block technique, which replicates the post-cam engaging position, provided consistent and accurate flexion gap measurements and reduced flexion–extension discrepancies. This approach enhanced knee stability and patient outcome post-TKA. • Novel spacer block simulates post-cam engagement for accurate flexion gap measurement. • Method enhances medial stability in JOURNEY II bicruciate stabilized total knee arthroplasty. • Technique achieved ≤2 ​mm medial flexion–extension gap matching in 92% of knees at 1 year.