Tsukiyama H, et al. - This study assessed the impact of joint laxity on clinical outcome after total knee arthroplasty (TKA), presuming that medial joint laxity correlates with inferior patient satisfaction and knee function, although lateral joint laxity is allowed to a certain degree in TKA. An inferior postoperative outcome resulted from knees with medial joint laxity during flexion and, there was no impact of lateral joint laxity on patient satisfaction or function. Notably, care should be taken to maintain medial joint stability during the TKA procedure.