Decreased medial posterior tibial slope is associated with an increased risk of posterior cruciate ligament rupture

Abstract

Purpose It remains unclear whether there is an association between posterior cruciate ligament (PCL) rupture and the medial posterior tibial slope (MTS) or lateral posterior tibial slope (LTS). The present case-control study aimed to investigate a possible association between primary PCL rupture and MTS or LTS measured by magnetic resonance imaging (MRI). Methods A retrospective case-control study was conducted. Patients with primary PCL ruptures but not with anterior cruciate ligament injuries, were 1:1 matched by age and sex to a control group with no evidence of knee ligament injuries. Knee MRI was used to measure the MTS and LTS. In addition, the receiver operating characteristic (ROC) analysis was performed to identify an optimal cut-of value of the MTS and/or LTS. Results In total, 46 patients with PCL ruptures (32 males, 14 females) and 46 controls (32 males, 14 females) were included in this study. The MTS was signiicantly lower in the patients with PCL ruptures (3.0° ± 2.2°) than in the control group (5.1° ± 2.3°, p < 0.001). The mean LTS/MTS ratio was signiicantly higher in patients with PCL ruptures (2.6 ± 2.5) than in the control group (1.3 ± 1.3, p = 0.001). However, the LTS was not signiicantly diferent between patients with PCL ruptures and the controls (4.4° ± 2.3° vs. 5.3° ± 2.6°, n.s.). After the MTS was determined to be a signiicant predictor, the ROC analysis was performed. The ROC analysis revealed the most accurate MTS cut-of of < 3.9°, with a sensitivity of 76.1% and a speciicity of 73.9%. Conclusion A decreased MTS and an increased LTS/MTS ratio are associated with an increased risk of primary PCL rupture. People with MTS < 3.9° are particularly at risk for PCL ruptures, and prevention and intervention programs for PCL ruptures should be developed and targeted towards them. Levels of evidence Level III.

Decreased posterior tibial slope is a risk factor for primary posterior cruciate ligament rupture and posterior cruciate ligament reconstruction failure: A systematic review

“…One study found that the 10‐year graft survival rates were 50% for those with an LTS of ≤3.8 versus 91.7% for an LTS of >3.8 ( p = 0.001) [26]. Three studies reported a mean LTS of 5.0 (range: 4.4–5.5) degrees in the PCL rupture group and 5.7 (range: 5.3–6.4) degrees in the control group [17, 18, 22]. Two studies found no significant difference in LTS between the PCL rupture and control groups [17, 22], while one study found that patients with PCL ruptures had significantly flatter LTS compared to controls ( p = 0.009) [18].…”

“…One study found that the 10‐year graft survival rates were 68.4% for patients with an MTS of ≤5.6° versus 92.6% for patients with an MTS of >5.6° ( p = 0.029) [26]. Four studies reported a mean MTS of 4.3 (range: 3.0–7.0) degrees in the PCL rupture or graft failure group and 6.5 (range: 5.0–9.2) degrees in the control group [17, 18, 22, 25]. All four studies found that patients with PCL injury had significantly flatter MTS than controls ( p < 0.001, p = 0.014, p = 0.023, p < 0.05).…”

“…The opposite is true for PCL injuries, as decreased PTS places increased tension and stress on the PCL rather than the ACL [26]. Specifically decreased MTS as opposed to LTS has an association with primary or secondary PCL injuries, with two studies in this review reporting near identical ROC cutoff values of below 3.9° and 3.93° being predictive for index PCL rupture and PCL graft failure, respectively [17, 22]. While various authors have suggested that a PTS of ≥12° should be considered pathologic given its role in ACL ruptures, these MTS cutoff values represent our most compelling evidence for characterising the lower extent of a pathological tibial slope [34–36].…”

“…Six studies [17,18,22,[24][25][26] comprising 689 patients reported on the association between PTS and primary PCL rupture or PCL graft failure (Table 2). Specifically, four studies examined LTS [17,18,22,26].…”

“…Six studies [17,18,22,[24][25][26] comprising 689 patients reported on the association between PTS and primary PCL rupture or PCL graft failure (Table 2). Specifically, four studies examined LTS [17,18,22,26]. One study found that the 10-year graft survival rates were 50% for those with an LTS of ≤3.8 versus 91.7% for an LTS of >3.8 (p = 0.001) [26].…”