Prevalence and risk factors of medial meniscal ramp lesions in patients undergoing primary anterior cruciate ligament reconstruction at a tertiary center

Abstract

Background

Ramp lesions are injuries of the peripheral meniscocapsular attachment of the posterior horn of the medial meniscus and are commonly associated with anterior cruciate ligament (ACL) tears. Failure to identify these lesions may compromise knee stability and outcomes after ACL reconstruction (ACLR).

Purpose

The primary objective of this study was to determine the prevalence of ramp lesions among patients undergoing primary ACLR at a tertiary center in Saudi Arabia. The secondary objective was to identify patient- and injury-related risk factors associated with ramp lesions.

Study design

Retrospective cross-sectional study.

Methods

This retrospective cross-sectional study included adult patients who underwent primary ACL reconstruction between November 2022 and December 2025. Patients with prior surgery, multiligamentous injuries (except MCL injuries), fractures, or incomplete records were excluded. Ramp lesions were identified intraoperatively. Demographic and clinical variables were analyzed using univariate logistic regression.

Results

Among 155 patients, ramp lesion prevalence was 3.9% (6/155). Older age and longer time from injury to surgery were significant predictors (p < 0.05). On continuous analysis, both age (OR = 1.151, 95% CI 1.024–1.294; p = 0.018) and time from injury to surgery (OR = 1.028, 95% CI 1.005–1.052; p = 0.017) remained significant. Sex, BMI, MCL injury, and lateral meniscal injury were not significantly associated.

Conclusion

Our findings suggest that older age and longer time from injury to surgery are associated with the occurrence of ramp lesions. Future prospective studies should assess the prevalence of ramp lesions while minimizing information and observer bias and should investigate the interplay among knee morphometry, activity level, and biomechanical forces leading to ramp lesion development across diverse populations. The relatively low prevalence observed in this study may be related to diagnostic limitations, as ramp lesions are often missed when only standard anterior arthroscopic portals are used. Techniques such as posteromedial exploration or trans-notch visualization may improve detection. Differences in surgical technique and surgeon awareness may also influence identification, highlighting the need for systematic intraoperative evaluation.

Introduction

The anterior cruciate ligament (ACL) is crucial for maintaining knee kinematics, and its injury represents a common and debilitating orthopaedic condition, ranging from intrasubstance stretching to complete tearing [1]. It is well-documented that ACL tears are frequently accompanied by other intra-articular pathologies, with concomitant injuries to the medial meniscus, lateral meniscus, or posterolateral corner (PLC) occurring in up to 43% of cases [2]. Biomechanical and clinical studies consistently demonstrate that failure to address these concomitant injuries can compromise knee stability and significantly increase revision rates following ACL reconstruction (ACLR) [2, 3].

While the failure rate of primary ACLR is relatively low, with approximately 3% of patients requiring revision surgery within five years [4], understanding the underlying causes of failure is critical. Traumatic reinjury remains the most frequent cause, followed by technical errors during the index procedure. However, unrecognized concomitant intra-articular lesions are increasingly identified as a significant contributing factor to residual laxity and graft failure [5].

Among these associated injuries, medial meniscal ramp lesions (RLs) have garnered particular attention. First identified by Hamberg et al. in 1983 [6] and later characterized by Strobel in 1988 [7], RLs are defined as injuries to the peripheral attachment of the posterior horn of the medial meniscus at the meniscocapsular junction. This pathology has historically been under-recognized, as it is frequently located within a posteromedial "blind spot" when using standard arthroscopic portals, making diagnosis challenging [6, 7].

The reported prevalence of ramp lesions varies widely in the literature, ranging from 9 to 17% [2, 8], with one study describing a “hidden” variant and reporting a prevalence as high as 40%, noting that 42% of these lesions were concealed behind a membrane-like structure [9]. This variability is partly attributable to differences in diagnostic methods used across studies. Studies relying primarily on preoperative MRI often report lower detection rates because MRI sensitivity for ramp lesions is highly variable, ranging from 27.3% to 84.6% [8, 10]. In contrast, studies employing systematic arthroscopic exploration of the posteromedial compartment, including trans-notch visualization or posteromedial portals, have reported substantially higher prevalence rates due to improved lesion detection [9]. Furthermore, differences in patient populations may contribute to the wide range of reported prevalence. Highly active athletic populations and patients with chronic ACL deficiency are more likely to sustain associated meniscal injuries, including ramp lesions, compared with less active cohorts. Therefore, variations in diagnostic techniques, activity levels, and injury chronicity should be considered when comparing prevalence rates across studies.

While the global burden of ACL injuries is substantial, with an estimated incidence of 68.6 per 100,000 person-years [11], regional epidemiological data are crucial for targeted healthcare planning. In the Middle East, comprehensive national registries are lacking. However, local studies from Saudi Arabia, particularly in Jeddah, have reported alarmingly high ACL prevalence rates, ranging from 5.3 to 25% in both athletic and general populations [12, 13]. These figures are significantly elevated compared with global averages, suggesting a potentially distinct regional risk profile. Furthermore, the specific prevalence of concomitant injuries, such as ramp lesions, and the associated risk factors within this population remain entirely unexplored. Given the potential for variations in injury patterns due to differences in knee morphology, sports participation, and healthcare access, extrapolating data from Western cohorts may be inadequate. Therefore, establishing regional baseline data is essential for developing accurate diagnostic protocols and effective treatment strategies tailored to the Middle Eastern population.

The primary objective of this study was to determine the prevalence of medial meniscal ramp lesions in patients undergoing primary ACL reconstruction at a tertiary center in Saudi Arabia. The secondary objectives were to identify patient-specific and injury-related risk factors associated with the presence of ramp lesions within this cohort.

Methodology

This was a retrospective, single-center, cross-sectional study conducted at Security Forces Hospital (SFHP) in Riyadh, Saudi Arabia. The study adhered to the STROBE guidelines for the reporting of observational studies. Data were collected from all eligible patients who underwent primary arthroscopic anterior cruciate ligament reconstruction (ACLR) between November 2022 and December 2025.

All consecutive adult patients (≥ 18 years) with a confirmed diagnosis of an isolated ACL rupture who underwent primary arthroscopic ACLR during the study period were eligible for inclusion.

Inclusion criteria

• Age 18 years or older.

• Confirmed ACL rupture treated with primary arthroscopic ACLR between November 2022 and December 2025.

• Availability of complete intraoperative documentation, including detailed intraoperative findings.

Exclusion criteria

• Age under 18 years.

• History of prior surgery (ipsilateral knee).

• Multiligamentous knee injuries involving the posterior cruciate ligament (PCL) or posterolateral corner (PLC). (Note: Patients with medial collateral ligament [MCL] injuries were included.)

• Presence of bony lesions, such as tibial plateau fractures or ACL tibial avulsion fractures.

• Revision ACL reconstruction.

• Missing or incomplete operative records.

Data were extracted retrospectively from hospital operative records and postoperative notes and entered into Excel forms that included demographic and clinical data. The primary outcome variable was the presence or absence of a medial meniscal ramp lesion. A ramp lesion was defined as a longitudinal tear of the posterior horn of the medial meniscus, specifically at the meniscocapsular junction or within the red-red zone, measuring ≤ 2.5 cm. Tears extending anteriorly from the posterior horn to form a bucket-handle tear were excluded.

Potential risk factors and descriptive variables collected included:

Demographic data: Age (as a continuous variable and categorized), sex, and body mass index (BMI). Clinical data: Time from injury to surgery (in months), presence of medial collateral ligament (MCL) injury, and presence of lateral meniscal injury.

To minimize selection bias, all consecutive patients meeting the eligibility criteria during the study period were included. Information bias was addressed by applying consistent, predefined diagnostic definitions for ramp lesions and other variables throughout the data extraction process.

A formal a priori sample size calculation was not performed, as this was a retrospective study aimed at including all eligible cases during the defined timeframe to provide a representative estimate of prevalence within this cohort.

To identify factors associated with the presence of ramp lesions, univariate binary logistic regression models were employed. Each potential predictor variable, both continuous and categorical, was individually assessed for its association with the presence or absence of a ramp lesion. For continuous variables, odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated per unit increase. For categorical variables, reference categories were established, and ORs with 95% CIs were calculated for each level against its respective reference. A p-value of less than 0.05 was considered statistically significant. Odds ratios were calculated using Haldane correction in cases with zero cells, where applicable, to avoid infinite values and ensure robust estimation.

This study was conducted in accordance with the Declaration of Helsinki. Ethical approval was obtained from the Institutional Review Board (IRB) of Security Forces Hospital, Riyadh (approval number: #). Due to the retrospective nature of the study and the use of de-identified data, the requirement for informed consent was waived.

All statistical analyses were performed using SPSS version 26.0 (IBM Corp., Armonk, NY, USA). Descriptive statistics were calculated for all demographic and clinical variables. Continuous variables were presented as means and standard deviations or medians and interquartile ranges, as appropriate. Categorical variables were presented as frequencies and percentages.

Results

Of the 175 patients initially enrolled, 20 were excluded due to incomplete data, leaving 155 patients for the final analysis. The mean age of patients without a ramp lesion was 31.4 years (95% CI 30.3–32.5), compared with 38.5 years (95% CI 31.4–45.5) in those with a ramp lesion. Among the 155 patients who underwent arthroscopic ACL reconstruction, 6 (3.9%) were found to have ramp lesions.

Demographic and categorical data are presented in Table 1. Age showed a significant association with ramp lesions (p = 0.047), with patients aged > 30 years having higher odds of ramp lesions (OR = 12.16, 95% CI 0.67–220.1) compared with those aged < 30 years (Table 2). Time from injury to surgery also demonstrated a significant association (p = 0.046). Patients with a delay > 24 months had increased odds of ramp lesions (OR = 5.26, 95% CI 0.92–30.0) compared with those with a delay ≤ 24 months. Sex, BMI category, MCL injury, and lateral meniscal injury did not show statistically significant associations with the presence of ramp lesions.

Table 1.

Demographic and baseline characteristics

Item	Total n (%)	No ramp lesion, n (%)	Ramp lesion, n (%)
Age in years, n (%)
< 20	6 (3.9)	6 (100)	0 (0.0)
20–30	66 (42.6)	66 (100)	0 (0.0)
30–40	64 (41.3)	60 (93.8)	4 (6.3)
> 40	19 (12.3)	17 (89.5)	2 (10.5)
Sex, n (%)
Male	149 (96.1)	144 (96.6)	5 (83.3)
Female	6 (3.9)	5 (3.4)	1 (16.7)
BMI, n (%)
Underweight < 18.5	4 (2.6)	4 (100)	0 (0.0)
Normal 18.5–24.9	38 (24.5)	36 (94.7)	2 (5.3)
Overweight 25–29.9	57 (36.8)	55 (96.5)	2 (3.5)
Obese ≥ 30	56 (36.1)	54 (96.4)	2 (3.6)

Table 2.

Collapsed categorical data

No ramp lesion n = 149	Ramp lesion n = 6	OR (95% CI)	p-value
72 (48.3)	77 (51.7)	Reference	0.047
0 (0.0)	6 (100)	12.16 (0.67–220.1)
144 (96.0)	5 (100)	Reference	1
6 (4.0)	0 (0.0)	2.02 (0.09–43.8)
92 (97.9)	2 (2.1)	Reference	0.046
35 (89.7)	4 (10.3)	5.26 (0.92–30.0)
40 (27.2)	107 (72.8)	Reference	0.176
0 (0.0)	6 (100)	4.90 (0.27–88.9)
147 (96.1)	6 (3.9)	Reference	1.00
2 (100)	0 (0.00)	*
73 (96.1)	3 (3.9)	Reference	1.00
76 (96.2)	3 (3.8)	0.96 (0.19–4.91)

OR = odds ratio; CI = confidence interval. Values were obtained from univariate binary logistic regression. Notes: Odds ratios were calculated using Haldane correction. *OR was not calculated because of a zero cell and the extremely small sample in the MCL injury group (n = 2)

When analyzed as continuous variables (Table 3), age (OR = 1.151, 95% CI 1.024–1.294; p = 0.018) and time from injury to surgery (OR = 1.028, 95% C: 1.005–1.052; p = 0.017) were significantly associated with the presence of ramp lesions. BMI did not show a statistically significant association (OR = 1.037, p = 0.229).

Table 3.

Continuous variables

Item	OR (95% CI)	p-value
Age (per 1-year increase)	1.151	0.018
BMI (per 1 kg/m2 increase)	1.037	0.229
Time from injury to surgery (per 1-month increase)	1.028	0.017

OR = odds ratio; CI = confidence interval. Values were obtained from univariate binary logistic regression

Discussion

The present study investigated the prevalence of and factors associated with ramp lesions in patients undergoing ACL reconstruction. Older age and longer time from injury to surgery were associated with the presence of ramp lesions. These findings are consistent with previous studies suggesting that both patient-related and injury-related factors may contribute to ramp lesion development in ACL-deficient knees [2, 14, 15].

The prevalence of ramp lesions in our cohort was 3.9%. Increasing age and longer time from injury to surgery were associated with higher odds of detecting a ramp lesion. Patients older than 30 years and those with a delay to surgery exceeding 24 months demonstrated a higher likelihood of having a ramp lesion. Given the limited number of events, these findings should be interpreted cautiously and considered exploratory.

The higher odds of ramp lesions in patients with a delay to surgery exceeding 24 months support the concept that ramp lesions may develop as secondary injuries following prolonged ACL deficiency [2, 16, 17]. Persistent rotatory and translational instability may progressively increase stress on the posterior horn of the medial meniscus, predisposing it to meniscocapsular injury [16, 17].

Although younger patients in our cohort had a lower prevalence of ramp lesions, this finding differs from some previous reports [16, 17]. One possible explanation is that patients in Saudi Arabia may reduce their activity level after injury, potentially limiting repetitive instability episodes before reconstruction. However, activity level was not assessed in the present study, and this hypothesis requires further investigation. Consistent with previous literature, delayed ACL reconstruction remains associated with an increased risk of secondary meniscal injury due to persistent instability and altered knee biomechanics [2, 14].

Several anatomical factors, including steeper medial tibial and meniscal slopes and variations in medial tibial plateau morphology, have also been associated with an increased risk of ramp lesions [14, 15]. Although these parameters were not evaluated in our study, previous reports have shown that Saudi individuals tend to have smaller knee dimensions than Western populations [18–20]. Whether these anatomical differences influence susceptibility to ramp lesions remains unknown and warrants further investigation.

The relatively low prevalence of ramp lesions observed in our cohort may also reflect differences in diagnostic techniques. Ramp lesions are frequently missed when only standard anterior arthroscopic portals are used because the posteromedial compartment is not directly visualized. Studies employing systematic posteromedial exploration or trans-notch visualization have consistently reported higher detection rates. For example, Thaunat et al. identified ramp lesions in 15.5% of 2156 ACL reconstructions, while Sonnery-Cottet et al. reported a prevalence of 23.9% using systematic trans-notch evaluation during ACL reconstruction [9, 21]. These findings suggest that variations in arthroscopic evaluation techniques, together with differences in patient populations, may substantially influence the reported prevalence of ramp lesions.

Limitations

This study is limited by its retrospective, single-center design and the small number of ramp lesion cases (n = 6), which reduces statistical power and the precision of the estimated associations. Consequently, the findings should be interpreted as exploratory and hypothesis-generating. Owing to the limited number of events, only univariate analyses were performed, precluding adjustment for potential confounding variables. Additionally, the diagnostic complexity of “hidden” ramp lesions and the lack of systematic posteromedial arthroscopic exploration may have resulted in underdiagnosis. Furthermore, detailed patient-level data, including activity level, injury mechanism, and anatomical knee morphology, were not available, limiting our ability to evaluate their influence on ramp lesion development. These limitations should be considered when interpreting the results and underscore the need for larger prospective, multicenter studies with sufficient numbers of events to permit robust multivariable analyses.

Conclusion

In conclusion, our findings emphasize the roles of age and time from injury to surgery in the occurrence of ramp lesions. Future research should explore the prevalence of ramp lesions prospectively to minimize information and observer bias and to investigate the interplay among specific knee morphometry, activity levels, and biomechanical forces leading to ramp lesions, particularly within diverse patient populations.

The relatively low prevalence observed may be due to diagnostic limitations, as ramp lesions are often missed when only standard anterior arthroscopic portals are used. Techniques such as posteromedial exploration or trans-notch visualization have been shown to improve detection. Differences in surgical technique and surgeon awareness may also influence identification, highlighting the need for systematic intraoperative evaluation.

Author contributions

Ahmad A., Eyad A., and Abdulaziz A. contributed to study conception and design. Ahmad A., Eyad A., Abdulaziz A., Mohammed A., and Faisal F.A. contributed to data collection. Faisal F.A. and Abdullah A.A. contributed to data analysis and interpretation. Faisal F.A. drafted the main manuscript text. Ahmad A., Eyad A., Abdulaziz A., Mohammed A., and Abdullah A.A. critically reviewed and revised the manuscript. All authors reviewed and approved the final manuscript.

Funding

The authors received no specific funding for this work.

Data availability

The datasets used and analyzed during the current study are available from the corresponding author upon reasonable request.

Declarations

Ethics approval and consent to participate

This study was approved by the Institutional Review Board (IRB) of Security Forces Hospital, Riyadh, Saudi Arabia. Due to the retrospective nature of the study and the use of de-identified data, the requirement for informed consent to participate was waived by the IRB.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.