Anterior cruciate ligament tear in Hong Kong Chinese patients

A Definition of Significant Instability and a Scoring System for Predicting Meniscal Tears in ACL-Deficient Knees

Background:

Patients with anterior cruciate ligament (ACL)–deficient knees risk recurrent instability of the affected knee, which may predispose to meniscal injuries. Various studies have correlated the incidence of meniscal tear with elapsed time from ACL tear and number of instability events. However, it is not clear how significant an instability event needs to be to contribute to a meniscal tear.

Purpose/Hypothesis:

The purpose of this study was to (1) define a significant instability episode and (2) develop a checklist and scoring system for predicting meniscal tears based on significant instability episode. We hypothesized that patients with ACL-deficient knees who met the scoring threshold for a significant instability episode would have a higher incidence of meniscal tears compared with those who did not meet the threshold.

Study Design:

Cohort study (prognosis); Level of evidence, 2.

Methods:

This retrospective study included patients with magnetic resonance imaging (MRI)–confirmed isolated ACL tear for longer than 3 months. We determined parameters for assessing instability episodes and defined any instability events between the MRI and ACL reconstruction as significant or insignificant. Patients were then grouped into a significant instability group (≥1 significant episode) and an insignificant instability group, and the incidence and types of meniscal tears found during surgery were compared between groups.

Results:

There were 108 study patients: 62 in the significant instability group and 46 in the insignificant instability group. During surgery, 58 meniscal tears (46 medial, 12 lateral) were recorded, for an overall meniscal injury rate of 53.70%. In the significant instability group, 47 patients (75.81%) had a meniscal tear and 15 (24.19%) had intact menisci (P < .001). In the insignificant instability group, 11 patients (23.91%) had a meniscal tear and 35 (76.08%) had intact menisci (P < .001). Regarding the 58 patients with a meniscal tear, 47 (81.03%) had ≥1 significant episode of instability before surgery, as compared with 11 (18.97%) who had insignificant or no instability. The odds of having a medial meniscal tear at ACL reconstruction was 10 times higher in the significant instability group versus the insignificant instability group.

Conclusion:

The incidence of a medial meniscal tear was 10 times greater in patients with a significant episode of instability versus those with insignificant instability, as defined using a predictive scoring system. The incidence of lateral meniscal tear did not change with instability episodes.

Chinese Ethnicity Is Associated With Concomitant Cartilage Injuries in Anterior Cruciate Ligament Tears

Background

Chinese ethnicity is associated with the presence of knee osteoarthritis. This raises the possibility that it may similarly be associated with concomitant meniscus and cartilage injuries in patients with anterior cruciate ligament (ACL) tears. There are currently no published data on the effect of Chinese ethnicity in this regard.

Purpose

The primary aim was to determine whether Chinese ethnicity is associated with concomitant intra-articular injuries in patients with ACL tears and to verify the correlation of age, sex, body mass index, mechanism of injury, cause of injury, and presence of bone contusions on magnetic resonance imaging with such injuries. A secondary purpose was to determine the optimal time frame for surgical reconstruction in patients with identified risk factors for concomitant injuries.

Study Design

Cohort study; Level of evidence, 3.

Methods

The medical records of 696 patients from a multiethnic population who underwent ACL reconstruction from January 2013 to August 2016 were retrospectively analyzed. Univariate and multivariate logistic regression analyses were performed to identify patient factors that were associated with medial meniscus tears, lateral meniscus tears, and cartilage injuries. Further univariate analysis was conducted to determine the earliest time point for surgery, after which the rate of concomitant injuries was significantly higher.

Results

Over half (69.1%, n = 481) of our study population sustained at least 1 other concomitant knee injury. Meniscus tears were most frequently associated with ACL tears (24.1% medial, 25.6% lateral, and 15.5% medial and lateral meniscus tears). Cartilage injuries were present in 18.4% of our cohort. Chinese ethnicity was associated with concomitant cartilage injuries. Increased age (≥30 years) was significantly associated with cartilage injuries and male sex with medial and lateral meniscus tears. Among patients with these factors, significantly fewer medial meniscus tears and cartilage injuries were noted when surgery was carried out within 12 months of the index trauma.

Conclusion

This is one of the first studies to have identified an association between Chinese ethnicity and concomitant cartilage injuries in ACL tears. This study also found an association between increased age and an increased prevalence of cartilage injuries. Male sex was associated with both medial and lateral meniscus tears. Definitive surgery should be performed within 12 months of the index injury to minimize further intra-articular injuries.