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Age and chronic ACL injury are associated with reduced ramp-region vascularity during ACL reconstruction
⁎Corresponding author: Tsuneari Takahashi. tsuneari9@jichi.ac.jp
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Received: ,
Accepted: ,
This article was originally published by Reed Elsevier India Pvt. Ltd. and was migrated to Scientific Scholar after the change of Publisher.
Abstract
Abstract
To evaluate arthroscopic vascularity of the medial meniscus ramp region during anterior cruciate ligament (ACL) reconstruction and to identify factors associated with reduced ramp-region vascularity.
This retrospective cohort study reviewed consecutive patients who underwent primary ACL reconstruction between January 2020 and January 2026. Ramp-region vascularity was assessed arthroscopically using a transcondylar view from the anterolateral portal and dichotomized as adequate versus not adequate based on visible synovial vessels and hyperemia, without inducing iatrogenic bleeding. Chronic ACL injury was defined as surgery performed ≥12 months after injury. Univariate comparisons were performed, followed by Bayesian information criterion (BIC)-based multivariable logistic regression analysis to identify independent factors associated with reduced ramp-region vascularity.
A total of 192 patients were screened, and 126 patients were included for analysis. Ramp-region vascularity was adequate in 74 patients and not adequate in 52 patients. Patients with reduced vascularity were significantly older than those with adequate vascularity (47.0 ± 17.5 vs 30.6 ± 17.0 years, P < 0.001), and chronic injury was more common in the reduced vascularity group (29/52 vs 12/74, P < 0.001). In multivariable analysis, older age was independently associated with reduced vascularity (odds ratio [OR], 1.04 per year; 95% confidence interval [CI], 1.01–1.07; P = 0.004). Chronic injury (not chronic vs chronic: OR, 0.273; 95% CI, 0.094–0.790; P = 0.017), arthroscopically visible ramp lesions (OR, 0.170; 95% CI, 0.058–0.494; P = 0.001), and preoperative Lysholm score (OR, 1.03; 95% CI, 1.01–1.06; P = 0.010) were also retained in the final model.
Reduced ramp-region vascularity during ACL reconstruction was independently associated with older age and chronic ACL injury. Patient age and injury chronicity may help identify knees with a biologically unfavorable ramp environment.
Keywords
Anterior cruciate ligament
Medial meniscus ramp lesion
Arthroscopy
Vascularity
Chronic ACL injury
1 Introduction
Medial meniscus pathology is a key factor influencing knee stability and long-term joint preservation, particularly in the setting of anterior cruciate ligament (ACL) injury. Medial meniscus ramp lesions are frequently encountered in ACL-injured knees, emphasizing the importance of careful intraoperative assessment.1 Biomechanically, disruption of posteromedial meniscocapsular structures has been shown to increase anterior tibial translation and rotational laxity in ACL-deficient knees, and repair can partially restore stability.2 However, most clinical investigations have primarily focused on mechanical instability and arthroscopic detectability rather than the biological environment surrounding the posterior horn of the medial meniscus.
Meniscal healing potential is strongly dependent on vascular supply. Clinically, the importance of healing quality has been highlighted by reports demonstrating that the healing status of ramp lesions may influence postoperative anterior knee stability after ACL reconstruction3,4). Meniscal microvasculature originates from a perimeniscal capillary plexus arising from capsular and synovial tissues and supplies only the peripheral portion of the meniscus. Subsequent work has further shown that meniscal vascularity is heterogeneous and may be diminished in abnormal or pathologic menisci,5,6 suggesting that local vascular conditions may influence intrinsic healing capacity. Importantly, ramp pathology may involve both the meniscocapsular junction and the meniscotibial attachment,7 supporting the concept that the ramp region represents a unique complex rather than a single uniform lesion.8
In a porcine ACL reconstruction model, Saitsu et al. demonstrated that leaving a medial meniscal ramp lesion untreated resulted in histological deterioration of the medial meniscus despite the absence of marked differences in anterior knee laxity or graft structural properties after cyclic loading.9 Together with experimental data showing that ramp lesion repair concomitant with ACL reconstruction does not necessarily result in superior anterior stability after cyclic loading10), these findings suggest that the clinical significance of ramp pathology cannot be explained solely by mechanical factors and that biological vulnerability of the posterior horn environment may contribute to persistent or progressive meniscal degeneration.
Despite this biological perspective, little is known about how vascularity in the ramp region varies among patients undergoing ACL reconstruction. In particular, patient age and injury chronicity may influence synovial vascular networks and peri-meniscal tissue quality, potentially resulting in a biologically unfavorable environment at the ramp region. Accordingly, the purpose of this study was to evaluate arthroscopic ramp-region vascularity during ACL reconstruction and to identify clinical factors associated with reduced vascularity.
2 Methods
2.1 Study design and study population
This retrospective cohort study included all consecutive patients who underwent primary anterior cruciate ligament (ACL) reconstruction between January 2020 and January 2026 at our institution. ACL injury was diagnosed based on clinical examination and magnetic resonance imaging (MRI). Patients who underwent revision ACL reconstruction, concomitant reconstruction of other major knee ligaments, or had insufficient arthroscopic assessment were excluded. A total of 192 patients were initially screened, and 126 patients remained for the final analysis after applying exclusion criteria.
2.2 Arthroscopic evaluation of the ramp region
After routine diagnostic arthroscopy through standard anterolateral and anteromedial portals, the posterior horn of the medial meniscus was assessed. The ramp region was evaluated through the intercondylar notch using a transcondylar view from the anterolateral portal. The posterior meniscocapsular junction and the meniscotibial attachment were inspected under direct visualization. The presence of an arthroscopically visible medial meniscus ramp lesion was recorded intraoperatively.
2.3 Arthroscopic assessment of ramp-region vascularity
Ramp-region vascularity was assessed arthroscopically under transcondylar visualization from the anterolateral portal. The peripheral portion of the posterior horn of the medial meniscus and the adjacent synovium were examined for visible synovial vessels and hyperemic changes around the ramp region. The rationale for vascular assessment is based on classical anatomical studies demonstrating that meniscal blood supply is limited to the peripheral portion and is supplied by a perimeniscal capillary plexus.5,6 To preserve the native biological environment, no intentional rasping, abrasion, or provocative maneuver was performed to induce bleeding during vascular evaluation.
Based on arthroscopic appearance alone, vascularity was categorized qualitatively as:•Adequate: clearly visible synovial vessels and/or marked hyperemia adjacent to the ramp region•Not adequate: sparse or poorly visualized vessels with minimal hyperemia, or absence of visible vessels and hyperemia (Fig. 1
For statistical analyses, vascularity was dichotomized as adequate vs not adequate.
2.3.1 Definition of injury chronicity
Time from injury to surgery was obtained from medical records. Chronic injury was defined as surgery performed ≥12 months after injury, whereas cases treated within 12 months were classified as not chronic.11
2.4 Data collection
Patient demographics (age at surgery, sex, height, weight, BMI, and affected side) and preoperative clinical variables were obtained from medical records. Preoperative anterior tibial translation was measured using instrumented laxity testing, and the side-to-side difference (SSD) was recorded. Preoperative pivot-shift grade and patient-reported outcome measures, including the Lysholm score and Tegner activity scale, were collected when available.
2.5 Statistical analysis
The primary outcome was reduced ramp-region vascularity, defined as vascularity categorized as not adequate. Continuous variables were compared using the independent-samples t-test or Mann–Whitney U test, as appropriate. Categorical variables were compared using Fisher's exact test.
To identify factors associated with reduced ramp-region vascularity, univariate analyses were first performed. Subsequently, multivariable logistic regression analysis was conducted. A Bayesian information criterion (BIC)-based variable selection approach was used to obtain a parsimonious final model.12 Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Statistical significance was set at P < 0.05. All analyses were performed using EZR software (Saitama Medical Center, Jichi Medical University, Saitama, Japan).13
3 Results
3.1 Patient characteristics
A total of 126 patients were included in the final analysis. Ramp-region vascularity was classified as adequate in 74 patients and not adequate in 52 patients. Patient demographics were shown on Table 1.
| Variable | Value |
| Age (years) | 37.4 ± 19.0 |
| Sex (female), n (%) | 46 (36.5%) |
| Side (Right), n (%) | 76 (60.3%) |
| Height (m) | 1.66 ± 0.10 |
| Weight (kg) | 65.0 ± 16.4 |
| BMI (kg/m2) | 23.5 ± 4.4 |
| Chronic injury, n (%) | 41 (32.5%) |
| Complete rupture, n (%) | 15 (11.9%) |
| Preoperative Tegner activity scale, median (IQR) | 5 (3–7) |
| Preoperative IKDC grade, n (%) | |
| Grade B | 2 (1.6%) |
| Grade C | 45 (35.7%) |
| Grade D | 78 (61.9%) |
| Missing | 1 (0.8%) |
| Preoperative SSD (mm) | 5.3 ± 2.2 |
| Preoperative pivot-shift grade, n (%) | |
| Negative | 9 (7.1%) |
| Glide | 47 (37.3%) |
| Clunk | 50 (39.7%) |
| Gross | 20 (15.9%) |
| Ramp vascularity (adequate), n (%) | 74 (58.7%) |
| Ramp vascularity (reduced/poor), n (%) | 52 (41.3%) |
3.2 Univariate analysis
Patients with reduced ramp-region vascularity were significantly older than those with adequate vascularity (47.0 ± 17.5 vs 30.6 ± 17.0 years, P < 0.001). There were no significant differences in BMI (22.9 ± 4.4 vs 23.8 ± 4.3 kg/m2, P = 0.242) or SSD in anterior tibial translation (4.88 ± 1.99 vs 5.58 ± 2.25 mm, P = 0.074) between groups.
Chronic ACL injury (≥12 months from injury) was significantly more frequent in the reduced vascularity group (29/52) compared with the adequate vascularity group (12/74) (P < 0.001). Arthroscopically visible medial meniscus ramp lesions were significantly less frequent in the reduced vascularity group (9/52) than in the adequate vascularity group (36/74) (P < 0.001). There were no significant group differences in sex, side, pivot-shift grade distribution, or ACL rupture type (complete vs partial).
Preoperative Tegner activity scale and Lysholm score differed significantly between groups. The reduced vascularity group had a lower Tegner activity scale (median 3 [IQR 3–5.25] vs 7 [IQR 4–7], P < 0.001) and a higher Lysholm score (median 69.5 [IQR 55.75–81] vs 55.0 [IQR 35.5–70], P < 0.001) (Table 2).
| Variable | Adequate vascularity (n = 74) | Not adequate (n = 52) | P value |
| Age, years | 30.6 ± 17.0 | 47.0 ± 17.5 | <0.001 |
| BMI, kg/m2 | 23.8 ± 4.3 | 22.9 ± 4.4 | 0.242 |
| Preoperative SSD, mm | 5.6 ± 2.2 | 4.9 ± 2.0 | 0.074 |
| Chronic injury (≥12 months), n/N | 12/74 | 29/52 | <0.001 |
| Visible ramp lesion, n/N | 36/74 | 9/52 | <0.001 |
| Female sex, n/N | 25/74 | 21/52 | 0.459 |
| Right knee, n/N | 42/74 | 34/52 | 0.36 |
| Preoperative pivot-shift grade, n | negative:5, glide:22, clunk:32, gross:15 | negative:4, glide:25, clunk:18, gross:5 | 0.134 |
| Complete ACL rupture, n/N | 12/74 | 3/52 | 0.096 |
| Preoperative Tegner, median (IQR) | 7.0 (4.0–7.0) | 3.0 (3.0–5.2) | <0.001 |
| Preoperative Lysholm, median (IQR) | 55.0 (35.5–70.0) | 69.5 (55.8–81.0) | <0.001 |
3.3 Multivariable logistic regression analysis
BIC-based multivariable logistic regression analysis demonstrated that older age was independently associated with reduced ramp-region vascularity (OR, 1.04 per year; 95% CI, 1.01–1.07; P = 0.0045). In addition, chronic injury (not chronic vs chronic: OR, 0.273; 95% CI, 0.094–0.790; P = 0.017) and arthroscopically visible ramp lesions (visible vs not visible: OR, 0.170; 95% CI, 0.058–0.494; P = 0.0012) were significant factors in the final model. Preoperative Lysholm score was also retained as an independent factor (OR, 1.03; 95% CI, 1.01–1.06; P = 0.010).
4 Discussion
The principal finding of the present study was that arthroscopically assessed ramp-region vascularity during ACL reconstruction was strongly associated with patient age and injury chronicity. Patients with reduced vascularity were significantly older than those with adequate vascularity, and chronic ACL injury (≥12 months from injury to surgery) was markedly more frequent among patients with reduced vascularity. Furthermore, BIC-based multivariable logistic regression analysis confirmed that older age and chronic injury remained independently associated with reduced ramp-region vascularity. These findings suggest that the biological environment surrounding the posterior horn of the medial meniscus is not uniform across ACL-injured knees and may be substantially influenced by patient-related and time-dependent factors.
From a biological standpoint, these results are consistent with the fundamental concept that meniscal healing potential depends on vascular supply. Meniscal microvasculature originates from a perimeniscal capillary plexus arising from capsular and synovial tissues and supplies only the peripheral portion of the meniscus.5 In addition, meniscal blood supply has been reported to differ between normal and abnormal menisci, supporting the notion that pathological conditions may compromise vascular support.6 Therefore, the observed reduction in vascularity in older and chronic cases may reflect a biologically disadvantaged ramp environment with diminished intrinsic healing potential. Clinically, this biological perspective is further supported by evidence showing that the healing status of ramp lesions may influence postoperative anterior stability after ACL reconstruction,4 indicating that biological conditions around the posterior horn should not be overlooked.
Injury chronicity may represent an important determinant of this biological environment. Chronic ACL deficiency is accompanied by prolonged abnormal tibiofemoral kinematics and repetitive microtrauma, which may lead to progressive meniscal damage and deterioration of peri-meniscal tissue quality. Although the present study cannot establish causality, the strong association between chronic injury and reduced vascularity suggests that delayed surgical timing may be associated with a biologically less favorable ramp environment at the time of ACL reconstruction.
Interestingly, arthroscopically visible ramp lesions were less frequently observed in the reduced vascularity group and remained a significant factor in the final multivariable model. This finding should not be interpreted as visible ramp lesions being biologically “protective.” Rather, it may reflect heterogeneity in the biological phase and timing of injury. Because meniscal vascular supply is derived primarily from perimeniscal capsular and synovial tissues and is limited to the peripheral zone,5 arthroscopic vascularity grading based on synovial vessels and hyperemia may be influenced by the presence of an active synovial response. In acute or subacute ACL injury, hyperemia adjacent to the posterior horn may be more prominent and a meniscocapsular separation may also be more readily apparent, resulting in a higher likelihood of classifying vascularity as adequate. Conversely, in chronic ACL-deficient knees, the ramp region may demonstrate a relatively “quiet” biological appearance with diminished hyperemia and fewer visible synovial vessels, leading to classification as reduced vascularity, even when overt meniscocapsular separation is not clearly visualized.
This interpretation is also compatible with previous experimental findings demonstrating that leaving a medial meniscus ramp lesion untreated resulted in histological deterioration of the medial meniscus in a porcine ACL reconstruction model.9 In addition, experimental findings have suggested that ramp lesion repair concomitant with ACL reconstruction does not always translate into improved anterior stability after cyclic loading.10 Taken together, these data support the concept that ramp pathology may involve biological consequences that are not fully captured by laxity measurements alone, and the local biological condition of the ramp region may influence vulnerability to degeneration or impaired recovery over time.
From a clinical perspective, surgeons should recognize that the arthroscopic biological appearance of the ramp region may vary substantially according to patient age and injury chronicity. In older or chronic ACL-deficient knees, reduced vascularity and limited hyperemic response may mask biologically vulnerable ramp tissue even when gross meniscocapsular separation is not evident. Therefore, careful and systematic evaluation of the ramp region remains important, and intraoperative assessment may benefit from considering both mechanical findings and biological appearance rather than relying solely on visual detectability. The association between reduced vascularity and higher preoperative Lysholm scores may reflect selection bias or differing activity demands, and should be interpreted cautiously.
4.1 Limitations
This study has several limitations. First, its retrospective design may introduce selection bias, and causal relationships between age, injury chronicity, and ramp-region vascularity cannot be established. Second, ramp-region vascularity was graded qualitatively based on arthroscopic appearance of synovial vessels and hyperemia. Although this method is practical and feasible intraoperatively, it is inherently subjective and may be affected by visualization conditions and surgeon interpretation. Interobserver or intraobserver reliability was not assessed in the present study. Third, vascularity was evaluated without inducing iatrogenic bleeding to preserve the native biological environment; therefore, direct confirmation of perfusion was not performed. Fourth, injury chronicity was determined from medical records and may be influenced by recall bias or incomplete documentation of the injury date. Finally, the present study did not include postoperative clinical outcomes or meniscal healing assessment, and further prospective studies are required to determine whether reduced ramp-region vascularity translates into inferior clinical results or altered healing potential after meniscal treatment.
5 Conclusion
Reduced ramp-region vascularity during ACL reconstruction was significantly associated with older age and chronic ACL injury. These findings suggest that patient age and injury chronicity may help identify knees with a biologically unfavorable ramp environment.
Guardian/patient's consent
Individual patient's consent was waived due to retrospective nature of this study.
Ethics approval
This study was conducted in accordance with the principles of the Declaration of Helsinki. Our Institute's Bioethics Committee for Ishibashi General Hospital Medical Research approved the study (Approval ID:2025-20) and waived the requirement for informed consent from individual participants given the retrospective study design. All patients received standard treatment.
Credit author statement
Tsuneari Takahashi; Conceptualization; Data curation; Formal analysis; Investigation; Methodology; Project administration; Supervision; Validation; Visualization; Roles/Writing – original draft; Writing – review & editing.
Katsushi Takeshita; Conceptualization; Project administration; Writing – review & editing.
Funding statement
Not applicable.
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