Impact of Anterior Cruciate Ligament Status on Early Satisfaction and Clinical Outcomes Following Total Knee Arthroplasty

Background: While total knee arthroplasty (TKA) is a successful treatment for debilitating arthritis, up to 20% of patients may be dissatisfied with their outcome. One hypothesis for dissatisfaction is the distortion of native knee kinematics following sacrifice of the anterior cruciate ligament (ACL) during TKA. The purpose of this study was to determine the impact of ACL status at the time of surgery in patients undergoing Posterior Stabilized (PS) TKA for osteoarthritis (OA). Methods: A consecutive prospective series of patients undergoing TKA by a single surgeon underwent prospective intraoperative assessment of their ACL status divided into three different groups:1) intact, 2) attenuated, or 3) deficient. Demographic, preoperative, intraoperative, and postoperative data were collected for each patient by two blinded, independent observers. Outcomes included patient satisfaction and Knee Society Score for Pain (KSS) and Function (KSF), Kellgren and Lawrence (K&L), UCLA Activity Score (UCLA), Short Form-12 (SF12), EuroQol (EQ5D) and patient satisfaction. Results: Of 116 patients, 33 (28.4%) patients had an ACL deficient knee, 40 (34.5%) patients had an attenuated ACL, and 43 (37.1%) patients had an intact ACL. Those with absent ACL were significantly more likely to have a higher BMI (p=.007) and be male (p=.003). Patient with a deficient ACL had significantly lower preoperative KSF and higher K&L scores (p=.009, p=1.26 x 10-7). Attenuated and deficient groups had the greatest change in SF12PCS scores at their one-year follow-up with increases of 9.9 (±10.0) and 10.8 (±8.0), respectively (p=.037). No significant differences in overall postoperative KSS, KSF and satisfaction scores based on ACL status (p=.574 and p=.529, respectively) were found. Conclusion: In a relatively large series, patient with ACL deficiency were more likely to have worse pre-operative outcome scores and similar or better post-operative outcome scores. This suggests that those with ACL insufficiency may experience more subjective improvement from TKA. ACL status can be used as an additional surgical marker to help orthopaedic surgeons identify which patients would most benefit from TKA.