Abstract
Objectives:
In anterior cruciate ligament (ACL) reconstruction, meniscal and cartilage injuries are critical factors that can significantly influence postoperative outcomes. Several factors have been reported as risk factors for increasing intra-articular injuries prior to surgery, one of which is the waiting period. Prolonged waiting periods before ACL reconstruction surgery have been reported to increase the incidence of cartilage and meniscus injuries. However, the impact of giving way episodes (GWEs) that occur during the waiting period on intra-articular knee injuries remains unclear, and it is not well understood how cartilage and meniscus injuries progress during this period. We hypothesized that GWEs during the waiting period could increase the incidence of intra-articular knee injuries. Therefore, the purpose of this study was to elucidate the effect of preoperative GWEs on intra-articular injuries in patients undergoing ACL reconstruction.
Methods:
We included 257 cases that underwent ACL reconstruction between 2022 and June 2024 and were enrolled in our multi-center study, the Chiba LEAF study. All procedures received IRB approval, and informed consent was obtained from all participants. All patients had a clearly defined onset of knee injury, underwent preoperative MRI, and had the presence of an ACL injury confirmed during arthroscopy. Only patients with a primary ACL rupture were included, while those with a history of either ipsilateral or contralateral ACL injuries were excluded. Multiple ligament injuries, age below 10 or above 60 years, radiographic evidence of osteoarthritic changes classified as grade 2 or higher by the Kellgren-Lawrence scale, previous knee trauma, and missing documentation of giving-way episodes were excluded. These exclusions were implemented to minimize the influence of degenerative changes and pre-existing conditions on the study outcomes. A total of 197 cases were analyzed statistically (female 60.4%; mean age 28.4 ±13.4 years; body mass index (BMI) 23.9 ± 4.2 kg/m2 ). A standardized preoperative questionnaire was used in all facilities, and cartilage and meniscus injuries were assessed at each center using standardized protocols and documented on uniform forms. Patients were categorized into three groups based on the number of preoperative GWEs: Group A (0-1 episode), Group B (2-5 episodes), and Group C (6 or more episodes). The presence of meniscus injury requiring intervention for tears exceeding 1.5 cm and cartilage damage of ICRS Grade 2 or higher were compared among the three groups. Meniscus injuries were classified as medial (MM) or lateral (LM), and cartilage injuries were categorized into medial (MC), lateral (LC), and patellofemoral (PFC) compartments. The presence of meniscus and cartilage injury were conducted using Fisher’s exact test. Furthermore, logistic regression analysis was performed with the presence of MM and LM injuries and cartilage injuries of MC, LC, and PFC as dependent variables and age, body mass index, GWEs, injury mechanism, Lachman test, sex, pivot shift test, Tegner activity scale, and waiting period were used as independent variables. All statistical analyses were conducted using R version 4.3.2, with statistical significance set at p < .05.
Results:
The overall incidence of associated injuries in all patients was 33.0% for MM tears, 48.7% for LM tears, 14.2% for MC injuries, 15.2% for LC injuries, and 7.6% for PFC injuries. Group A had a lower frequency of MM tears compared to Group C (21.8% vs. 52.4%, p<0.001 ) and Group C had a higher frequency of cartilage injury of LC (4.5% vs. 2.0% vs. 13.5%, p<0.01 ) [Table 1]. Logistic regression analysis identified high pivot shift test grade (OR 2.79, 95% CI 1.32-5.87, p=0.007) and GWEs (Group B: OR 3.72, 95% CI 1.57-8.77, p=0.002; Group C: OR 3.29, 95% CI 1.18-9.17, p=0.022) as risk factors for MM tears. High BMI, a high-grade Lachman test, and a higher Tegner activity scale were identified as risk factors for LM tears [Table 2]. Age was identified as a risk factor for cartilage injuries in the lateral and patellofemoral compartments [Table 3]
Conclusions:
A prolonged waiting period has been reported as a risk factor for MM injury in knees with ACL tear. However, this study introduced a factor, "Giving Way Episodes" to examine not only the length of the waiting period but also how patients spent their time during that period. The finding revealed that experiencing two or more GWEs independently increased the risk of MM injuries threefold, regardless of the waiting period.
