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Background: There is still debate regarding the association between arthrometric knee laxity measurements and subjective knee outcome and revision surgery after primary anterior cruciate ligament reconstruction (ACLR). Purpose: To assess whether arthrometric knee laxity (measured with the KT-1000 arthrometer) 6 months after primary ACLR was associated with the 1-, 2-, and 5-year subjective knee outcomes or revision ACLR at a 5-year follow-up. Study Design: Cohort study, Level of evidence 3. Methods: Patients who underwent primary ACLR with a hamstring tendon autograft at the authors’ institution between January 1, 2005, and December 31, 2017, with no concomitant ligamentous injuries, were identified. Anterior knee laxity (KT-1000 arthrometer, 134 N) was assessed 6 months postoperatively. The Knee injury and Osteoarthritis Outcome Score (KOOS) was collected preoperatively and 1, 2, and 5 years postoperatively. Patients who underwent revision ACLR at any institution in the country within 5 years of primary surgery were identified through the Swedish National Knee Ligament Registry. Results: A total of 4697 patients (54.3% male) with available KT-1000 arthrometer measurements were included (normal: side-to-side STS ≤2 mm, 3015 64.2%; nearly normal: STS 3-5 mm, 1446 30.8%; abnormal: STS >5 mm, 236 5.0%). The only significant difference in subjective knee outcome between the groups was for the KOOS Symptoms subscale at the 1-year follow-up (STS ≤2 mm, 79.9 ± 16.2; STS 3-5 mm, 82.5 ± 14.8; STS >5 mm, 85.1 ± 14.2; P 5 mm (11.4%; 27/236) (HR, 2.61; 95% CI, 1.69-4.03; P 5 mm) 6 months after primary ACLR was associated with an increased hazard of revision ACLR within 5 years, but it was not associated with an inferior subjective knee outcome.
Cristiani et al. (Fri,) studied this question.