Summary

Similar functional outcome but impaired health related quality of life with bilateral ACL surgery.

Abstract

Introduction

A patient with an ACL-reconstructed knee (ACLR), has a great risk of sustaining a new ACL injury in either knee. Paterno et al. reported that in an active, young population who returned to pivoting activities that 25.4% sustained a new ACL injury. 75% of these injuries were to the contralateral knee. Data from the Swedish Knee Ligament Registry report a contralateral ACLR rate of close to 5% at a 5-year follow-up after primary ACLR.

The purpose of this study was to 1, identify pre-, intra- and postoperative risk factors associated with contralateral ACLR 2, compare knee laxity and functional knee outcome between primary and contralateral ACLR and 3, compare activity level, patient-reported knee function at a minimum of 5 years follow-up.

Methods

1, Primary ACLR, 2005–2014 (n= 5393) and occurrence of a contralateral ACLR within 5 years. Regression analysis [age, gender, body mass index, time from injury to surgery, pre-injury Tegner], intraoperative [graft type, meniscus injury, cartilage injury] and postoperative [limb symmetry index (LSI) for quadriceps and hamstring strength and single-leg-hop test performance] as risk factors for a contralateral ACLR.
2, Same patients who underwent primary and contralateral ACLR (n= 326). The KT-1000 for knee laxity and KOOS for subjective outcome.
3, Bilateral ACLR, = 40 years. KOOS, EQ-5D and EQ-VAS and study-specific questions regarding activity level and knee function at a minimum 5-year follow-up. For every patient with a bilateral ACLR, a control matched for age ± 2 years, gender, year of ACLR and pre-injury activity level or sport at the time of injury was identified.

Results

1, The overall incidence of a contralateral ACLR within 5 years was 4.7%. Multivariable analysis revealed that the risk of contralateral ACLR was significantly affected by age (OR 0.40; 95% CI 0.28 – 0.58; P < 0.001), time from injury to surgery (OR 0.48; 95% CI 0.30 – 0.75; P = 0.001) and single-leg-hop test (OR 1.56; 95% CI 1.04 – 2.34; P = 0.03).
2, The mean preoperative and postoperative anterior tibial translation (ATT) and ATT reduction were not different between primary and contralateral ACLR. No significant differences were found for any of the five KOOS subscales at 2 years.
3, A total of 98 patients (mean age ? SD, 33.3 ? 7.3) with a bilateral ACLR and 98 patients with unilateral ACLR (mean age ? SD, 33.1 ? 7.7) were included. The mean postoperative follow-up was 7.6 ± 1.8 years. Patients with a bilateral ACLR reported lower scores on all KOOS subscales, the EQ-5D and the EQ-VAS at follow-up (P < .05). There was no difference in activity level between the groups at the follow-up, but patients with a bilateral ACLR were less satisfied with their activity level and knee function (P < .05).

Conclusion

The 5-year incidence of contralateral ACLR was 4,7%. Most important risk factors were good functional outcome at 6 months follow-up. Knee laxity and functional knee outcome after contralateral ACLR are comparable to those after primary ACLR but long term patient-reported knee function and health-related quality of life were inferior in patients with a bilateral ACLR compared to patients with a unilateral ACLR.