Summary

Positive genu recurvatum was associated with a statistically significantly lower risk of ACL re-injury, and higher ACL-QoL scores were associated with younger age, positive GJH, and positive GR.

Abstract

Purpose

The primary purpose of this study was to assess whether generalised joint hypermobility or genu recurvatum influenced the objective clinical, functional performance, or quality of life outcomes of patients following isolated primary hamstring autograft anterior cruciate ligament reconstruction (ACLR).

Methods

Patients (n=1449) were included following an isolated primary ACLR with hamstring autograft. Data was prospectively collected between 2010-2015 from a single center. Demographic and clinical information were collected, including age, sex, body mass index (BMI), generalized joint hypermobility (GJH), and genu recurvatum (GR). Lachman and Pivot-shift tests, and Functional tests, including single-leg balance and the 4 single-leg hop tests were used to assess limb symmetry indices (LSI) at 2-years post-operative. Patients completed the ACL-QoL questionnaire pre- and 1- and 2-years post-operative. Descriptive statistics were used to assess patient demographics, surgical details, ACL graft injury rate, LSI, and ACL-QoL scores. Differences in ACL-QoL scores from pre- to post-operative were evaluated using a one-way ANOVA. Multiple regression analyses were utilized to assess the influence of demographic and anatomic variables on clinical and QoL outcomes.

Results

The study cohort included 776 males (53.6%) and 673 females (46.4%), with a mean age of 30 years (SD ±10.5), and mean BMI of 24.8 (SD ±3.8). Positive GJH (Beighton score ≥ 4) was assessed for 546 (37.7%) patients, and GR measured ≥10 in 728 (45.9%) knees. Mean graft diameter was 7.6mm, and intra-operative assessment revealed 949 (65.5%) knees had meniscal injuries and 452 (31.2%) had chondral injuries.

At 2-years post-operative, 1179 (81.4%) patients completed clinical follow-up and 1335 (92.1%) completed the ACL-QoL. ACL graft re-injuries were confirmed in 70 knees (4.8%). The 4 single-leg hop tests demonstrated an LSI of 98.9% at 2-years. Mean ACL-QoL scores before surgery were 28.8/100 (SD ±13.7), with evidence of statistically significant increases to 71.0 (SD ±19.5) at 1-year, and 77.2 (SD ±19.4) at 2-years post-operative (p<0.001).

Multiple regression analysis revealed ACL graft reinjuries were associated with younger age, with each additional year of age reducing the odds of ACL re-injury by 7.1%, p-value = 0.043. Positive GR was associated with approximately 80% lower chance of ACL re-injury, p-value = 0.019. Gender, GJH, and meniscal injury did not significantly affect the likelihood of ACL re-injury.

The regression model for the ACL-QoL score revealed an r2 = 0.993, demonstrating that the model provided a robust explanation of the variance in the QOL score with a high significance level and strong predictive power. Younger age at surgery (t-value 2.53, p = 0.012 ), positive GJH (t-value 7.17, p = 0.000) and presence of GR (t-value 8.21, p = 0.000) were all statistically significantly associated with higher ACL-QoL scores. Intra-operative chondral pathology (t-value 2.02, p = 0.043) and lower graft diameter (t-value 6.27, p = 0.000) were statistically significantly associated with lower ACL-QoL scores. Regarding functional performance, for each unit increase in LSI, the ACL-QoL increased by approximately 0.31 points, indicating a positive linear relationship between functional performance and patient-reported QOL score.

Conclusion

In this 1449 primary hamstring ACLR study the follow-up rate was 81.4%, and 70 ACL re-injuries (4.8%) were assessed at 2-years post-operative. ACL re-injuries were statistically significantly associated with younger age. Positive genu recurvatum was associated with a statistically significantly lower risk of ACL re-injury. Higher ACL-QoL scores were associated with younger age, positive GJH, positive GR and higher LSI.