Adequate joint line restoration and good preliminary clinical outcomes after total knee arthroplasty using the Flexion First Balancer technique

Introduction: Up to 20% of patients are dissatisfied after total knee arthroplasty (TKA). Factors which could possibly contribute to this dissatisfaction are a decreased posterior condylar offset (PCO) and subsequent joint line elevation which leads to mid-flexion instability. The Flexion First Balancer (FFB) technique aims to adequately restore the medial PCO and thereby reconstruct the medial native joint line to its pre-disease height. Methods: A retrospective cohort of 59 patients operated using the FFB technique was analyzed and matched with a historic measured resection (MR) cohort of 59 patients. Groups were matched for age, gender, BMI and ASA classification. Joint line and PCO changes as well as patient reported outcome measurement scores (PROMs) were evaluated at one year [1.0 – 1.6] postoperatively. Results: Radiographic evaluation revealed no changes in joint line height in the FFB group, whereas an elevation in joint line was seen in the MR group (p = 0.002). The PCO increased after surgery in both group without any statistically significant differences. Evaluation of PROMs found no differences between the two groups for total OKS and KOOS scores, nor in re-operation or complication rates. Conclusion: The FFB technique seems to be a safe technique to use in TKA and reconstructs the pre-disease joint line in contrast to the MR technique. The clinical outcomes were comparable between both groups