Purpose
To investigate the correlation between surgical delay and the incidence of ramp lesions by performing meticulous arthroscopic evaluation of the posterior compartment in patients undergoing anterior cruciate ligament (ACL) reconstruction.
Methods
This retrospective cohort study included patients who underwent primary ACL reconstruction between July 2015 and January 2023. To minimize underdiagnosis of ramp lesions, all patients received comprehensive arthroscopic evaluation of the posterior compartment via intercondylar notch view and posteromedial or posterolateral portals. Meniscal tears were classified on the basis of Cooper’s system, and radial and longitudinal tear components were analyzed separately. Patients were categorized into 3 groups according to time from injury to surgery: group 1 (<6 weeks), group 2 (6 weeks–6 months), and group 3 (>6 months). Incidence and tear patterns were compared among groups.
Results
A total of 201 patients were included in the study. The overall incidence of meniscal tears was lowest in group 2 (50%) compared with group 1 (73%; P =.02) and increased again in group 3 (75%; P =.04 vs group 2). Ramp lesions were significantly more common in group 3 than in group 2 (52.8% vs 23.1%; P =.02). Medial bucket-handle tears also increased significantly in group 3 (22.2%) compared to group 1 (2.9%) and group 2 (0%) ( P <.01 and P =.02, respectively).
Conclusions
A surgical delay of more than 6 months was associated with a higher incidence of medial ramp lesions, which can progress to bucket-handle tears in ACL-deficient knees. Early surgical intervention should be considered in ACL ruptures accompanied by rotational instability to prevent progression of medial meniscal pathology.
Level of Evidence
Level III, retrospective cohort study.
Longitudinal tears at the menisco-capsular junction of the medial meniscus, commonly referred to as ramp lesions, are associated with anterior cruciate ligament (ACL) injuries. , Recent studies have underscored the critical role of ramp lesions in contributing to both anterior and rotatory instability of the knee, ,,,, thereby garnering increased clinical and research interest. The proposed pathomechanism of ramp lesions is a contrecoup mechanism, in which a subluxated femur reduces during pivoting movements, leading to excessive stress at the menisco-capsular junction. Although the incidence of ramp lesions varies across studies, recent literature reported that these injuries may occur in up to 42% of patients with ACL ruptures. ,,,,
Ramp lesions occur in the highly vascularized red-red zone of the meniscus, which theoretically confers a strong potential for self-healing. However, the altered biomechanics following an ACL rupture may result in repetitive pivoting movements, which can further hinder healing and lead to de novo ramp lesions or exacerbate pre-existing ones. , In addition, the loss of ACL function leads to repetitive pathological pivoting movements, potentially contributing to the occurrence of ramp lesions, even in cases in which they were absent at the initial ACL injury.
Previous studies have reported an increased incidence of medial meniscus tears in cases of delayed ACL reconstruction. , The effect of surgical delay on the incidence of ramp lesions remains controversial, with some studies reporting no clear correlation, whereas others have demonstrated a higher incidence of ramp lesions in patients undergoing delayed ACL reconstruction. ,, Moreover, the reported incidence of ramp lesions may vary depending on surgical timing and diagnostic methodologies. In particular, the sensitivity of MRI-based radiologic evaluation for detecting ramp lesions is estimated to be ∼71% , potentially leading to underdiagnosis. Therefore, meticulous arthroscopic assessment of the posterior joint space—utilizing a 70° arthroscope via the intercondylar notch or a posteromedial viewing portal—is regarded as the gold standard for accurate diagnosis ( Fig 1 ). ,,,
Arthroscopic finding of meniscal tear at posterior menisco-capsular junction. (A) Arthroscopic view of the right knee using a 30° scope passed through the intercondylar notch to visualize the posteromedial compartment. No evident tear is observed at the posterior menisco-capsular junction of the medial meniscus. (B) In the same patient, switching the viewing portal to a posteromedial (PM) portal reveals a ramp lesion at the posterior menisco-capsular junction that was not identified through the intercondylar notch with the 30° scope. This finding underscores the potential for missed lesions, especially when the capsular side of the ramp lesion is located posteroinferiorly. (C) Arthroscopic view of the left knee using a 30° scope passed through the intercondylar notch to assess the posterolateral compartment. A blood clot is noted at the posterior menisco-capsular junction of the lateral meniscus, but no definite tear is visualized. (D) Upon switching to a 70° arthroscope and probing the same region, a longitudinal tear at the posterior menisco-capsular junction of the lateral meniscus was clearly identified. The tear pattern was analogous to that of a medial ramp lesion. When the lesion is located closer to Zone 1 in Cooper’s classification, the limited visualization provided by a 30° scope may result in missed diagnoses. In such cases, the use of a 70° scope or conversion to a posteromedial or posterolateral viewing portal is recommended to improve detection, particularly in acute injuries. The presence of a blood clot at the menisco-capsular junction should raise suspicion for an occult tear and warrants thorough inspection. Ant, anterior; Inf, inferior; LFC, lateral femoral condyle; LM, lateral meniscus; MFC, medial femoral condyle; MM, medial meniscus; PMCJ, posterior menisco-capsular junction; Post, posterior; Sup, superior.
The purpose of this study was to investigate the correlation between surgical delay and the incidence of ramp lesions by performing meticulous arthroscopic evaluation of the posterior compartment in patients undergoing ACL reconstruction. The hypothesis of this study was that surgical delay exceeding 6 months may increase the incidence of ramp lesions due to prolonged exposure to abnormal knee biomechanics.
Methods
Patient Selection
The inclusion criteria comprised patients who underwent primary ACL reconstruction performed by 2 experienced, fellowship-trained sports medicine surgeons (D.H.K. and D.K.L.) at 2 tertiary care institutions between July 2015 and January 2023. ACL reconstruction was indicated for patients diagnosed with ACL rupture on preoperative MRI who exhibited rotational instability—defined as a grade 1 or higher pivot-shift test—during physical examination under anesthesia prior to surgery. A total of 249 patients met these criteria and were initially included in the study. This study was approved by the Institutional Review Board (IRB number: SCMC 2024-06-012).
The exclusion criteria for the study were as follows: (1) patients without arthroscopic images (n = 2), making retrospective analysis of meniscus injuries impossible; (2) patients with multiligament injuries or a fracture, in which the injury mechanism is different from the primary ACL ruptures (n = 37); and (3) patients with radiographic osteoarthritis classified as Kellgren–Lawrence grade II or higher (n = 4) or a history of ipsilateral knee joint surgery (n = 5), making it difficult to determine whether a meniscal tear occurred concomitantly with the ACL rupture.
After applying the exclusion criteria, 201 patients were enrolled in this retrospective cohort study ( Fig 2 ). The demographic characteristics of the study population are presented in Table 1 . Patients were divided into 3 groups based on surgical delay, which was defined as the time from initial trauma to ACL reconstruction. Patients were divided into 3 groups based on time from injury to ACL reconstruction: group 1 (<6 weeks), group 2 (6 weeks to 6 months), and group 3 (>6 months). The cut-offs were selected to reflect the acute postinjury period (<6 weeks), a subacute-to-intermediate phase (6 weeks–6 months), and a chronic phase (>6 months), consistent with clinical observations and previously published literature regarding the progression of secondary meniscal injury in ACL-deficient knees. , In patients of group 2 and group 3 who underwent surgical treatment more than 6 weeks after injury, all cases exhibited grade I or higher rotational instability on pivot-shift testing at the initial outpatient visit. Surgical treatment was performed on the basis of rotational instability and was not intentionally delayed for study purposes. The reasons for surgical delay included (1) patient-related factors, such as scheduling conflicts or personal circumstances that prevented timely consultation or surgery; (2) cases in which initial symptoms improved after injury, but patients later presented to the hospital due to recurrent instability or knee pain during the follow-up period, resulting in delayed diagnosis and subsequent treatment; and (3) delayed referral from local clinics where the initial ACL injury was not accurately diagnosed.
Flowchart.
Table 1
Demographic Characteristics
|
Group 1
(n = 139) |
Group 2
(n = 26) |
Group 3
(n = 36) |
P Value | ||
|---|---|---|---|---|---|
| Age (year) |
30.5 ± 14.7
(14-59 year) |
32.6 ± 16.1
(15-57 year) |
30.4 ± 13.7
(16-55 year) |
.403 | |
| Gender | Male | 104 (74.8%) | 20 (76.9%) | 28 (77.8%) | .922 |
| Female | 35 (25.2%) | 6 (23.1%) | 8 (22.2%) | ||
| Side of injured knee | Right | 76 (54.7%) | 15 (57.8%) | 20 (55.6%) | .960 |
| Left | 63 (45.3%) | 11 (42.2%) | 16 (44.4%) | ||
| Duration from trauma to ACL reconstruction (days) |
16.4 ± 10
(1-42 days) |
90.7 ± 35
(49-171 days) |
863.5 ± 663.9
(192-2540 days) |
<.001 , | |
| Injury Mechanism | Noncontact injury | 119 (85.6%) | 22 (84.6%) | 30 (83.3%) | .941 |
| Contact injury or direct trauma | 20 (14.4%) | 4 (15.4%) | 6 (16.9%) | ||
| Cause of injury | Twisting | 90 (64.7%) | 18 (69.2%) | 21 (58.3%) | .064 |
| Slip down | 14 (10.1%) | 2 (7.7%) | 5 (13.9%) | ||
| Jump and landing | 23 (16.6%) | 4 (15.4%) | 1 (2.8%) | ||
| Miscellaneous | 12 (8.6%) | 2 (7.7%) | 9 (25%) |
‡ Statistically significant ( P <.05).
All surgical records and arthroscopic images were retrospectively reviewed by one of the authors (D.K.L.), who performed the procedures. The reviewer is a board-certified knee surgeon with more than 10 years of experience in arthroscopic surgery.
Diagnostic and Surgical Procedure
Prior to primary ACL reconstruction, the Lachman test and pivot shift test were performed on patients with suspected ACL tears based on MRI findings. Patients who exhibited grade I or higher on the anterior drawer test, Lachman test, or pivot shift test were diagnosed with ACL rupture or insufficiency and subsequently underwent primary ACL reconstruction.
In all patients undergoing ACL reconstruction, two surgeons performed a diagnostic arthroscopic examination via the anterolateral or anteromedial portal to assess for meniscal tears. One surgeon (D.H.K.) evaluated the posterior compartments using a 70° arthroscope passed through the intercondylar notch. The other surgeon (D.K.L.) used the same technique and additionally confirmed findings using a posteromedial or posterolateral portal as a secondary viewing portal. Because of the retrospective nature of the study, the specific portal used for the final diagnosis of each meniscal tear was not consistently recorded. If a meniscal tear was deemed unstable, meniscal repair was performed concurrently with ACL reconstruction.
Data Collection
A single surgeon (D.K.L.) retrospectively reviewed the surgical records of all patients. The type and location of meniscal tears were reconfirmed through arthroscopic image analysis. The meniscal tear locations were documented using Cooper’s classification system ( Fig 3 ). Additionally, meniscus tears were further categorized into radial and longitudinal tear components for detailed analysis. Radial or oblique tears occurring within ∼1 cm of the meniscal root bony insertion were defined as root tears. The incidence of root tear was recorded as a subgroup of the radial tear component. Ramp lesions were defined as meniscocapsular injuries involving the posterior horn of the medial meniscus. Bucket-handle tear was defined as a longitudinal tear that continuously involves 2 adjacent zones, according to Cooper’s classification, and is considered unstable upon arthroscopic probing if the tear showed displacement into intercondylar notch or around the femoral condyle. The incidence of bucket-handle tears was recorded as a subgroup of the longitudinal tear component.
Cooper’s classification. The meniscal tear locations were documented using Cooper’s classification system.
Statistical Analysis
The χ 2-test was performed to compare the incidence of meniscal tears among the groups. Statistical significance was defined as P <.05. All statistical analyses were conducted using SPSS version 20 (IBM). Significance was set at P <.05.
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