Introduction: Few studies have evaluated the concomitant effect of both total knee arthroplasty (TKA) limb alignment and ligament laxity. Therefore, the primary aim of this study is to evaluate the impact of lower extremity alignment on the short-term outcome (one year) following TKA, including pain relief, function, and patient satisfaction. The secondary aim of the study is to evaluate the impact of ligament laxity and balance on early outcomes following TKA.
Materials and methods: A prospective evaluation of mechanical alignment and ligament tension was performed for 110 consecutive TKAs using an identical surgical technique. Patients were evaluated with knee society score, visual analog pain score, and satisfaction one year following TKA. Linear regression analysis was then performed to determine the effect of lower extremity alignment and ligament laxity.
Results: There was no significant relationship between lower extremity alignment and outcome measures. A significant relationship was identified between medial collateral laxity in full extension and knee society scores for function, but not for pain. There was also a significant relationship identified between lateral knee laxity at 90 degrees of flexion and knee society score and pain at one-year follow up.
Conclusion: Our results demonstrated no correlation between mechanical alignment restoration and pain or function. However, more interestingly, this study found patients with medial laxity in extension and lateral laxity in knee flexion, similar to normal physiologic knee laxity, to have less pain and greater function and satisfaction at one-year short-term follow up.