Morphological Risk Factors for Posterior Cruciate Ligament Tear and Tibial Avulsion Injuries of the Tibial Plateau and Femoral Condyle

Abstract

Background: Identification of morphological risk factors associated with the knee that threaten ligaments is important for understanding injury mechanisms and prevention. However, the morphological risk factors for posterior cruciate ligament (PCL) lesions are not clearly understood. Purpose: To investigate whether the medial tibial depth (MTD), medial and lateral posterior tibial slope, asymmetry of the medial and lateral slopes, radius of the sagittal plane medial femoral condyle, coronal tibial slope, and notch width index (NWI) were risk factors for PCL intrasubstance tearing (PCLIT) and tibial avulsion fractures (PCLAF). Study Design: Cross-sectional study; Level of evidence, 3. Methods: Between January 2015 and March 2022, 82 patients with isolated PCLIT, 68 patients with isolated PCLAF, and 82 controls without any ligamentous or meniscal pathologic findings as determined via physical examination and magnetic resonance imaging were included. Values were compared among the 3 groups. Logistic regression analysis was performed to confirm the risk factors. Receiver operating characteristic curves were defined for the morphological indicators and combination of risk factors. Results: Logistic regression analysis revealed (1) MTD, lateral minus medial posterior tibial slope, radius of the posterior circle of the medial femoral condyle, and NWI as significant independent predictors for PCLIT and (2) MTD and NWI for PCLAF. The areas under the curve combining the 4 indicators for PCLIT and noncontact PCLIT were 0.79 (95% CI, 0.72-0.86) and 0.90 (95% CI, 0.85-0.96), respectively. The area under the curve for the combination of MTD and NWI for PCLAF was 0.78 (95% CI, 0.70-0.86). Conclusion: Decreased MTD and NWI were associated with an increased incidence of PCLIT and PCLAF. Increased asymmetry of the medial and lateral slopes and the radius of the posterior circle of the medial femoral condyle were associated with the presence of PCLIT. In addition, the model of a combination of risk factors showed good predictive ability for noncontact PCLIT. These findings may aid clinicians in identifying patients at risk for PCL lesions. Further studies are warranted for identifying the effect of these factors on biomechanical mechanisms.

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 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).…”

“…One study reported an AUC of 0.765 and an MTS cutoff of under 3.9° being predictive of PCL rupture, with a sensitivity and specificity of 76.1% and 73.9%, respectively [22]. Another study reported an AUC of 0.690 and an MTS cutoff of under 3.93° being predictive of PCL rupture in males, with a sensitivity and specificity of 68.4% and 81.4%, respectively ( p < 0.001) [17]. In one study, a simple logistic regression analysis of MTS was found to be predictive of PCL rupture with a significant OR of 1.19 (95% CI, 1.04–1.37, p = 0.011); however, this relationship did not remain significant after multivariate analysis with an adjusted OR of 1.20 (95% CI, 0.95–1.52, n.s.)…”

“…The mean notch width was 18.3 (range: 15.4–21.0) mm in the PCL rupture group and 18.6 (range: 15.8–22.0) mm in the control group. Three studies reported no significant difference in mean notch width between the PCL rupture and control group [15–17], while another study found that notch width is significantly larger in females with PCL ruptures compared to female controls ( p = 0.03) [23].…”

“…Three studies consisting of 469 patients reported on femoral condylar width (Table 4) [15,17,23]. The mean femoral condylar width was 75.7 (range: 66.3-78.00) mm in the PCL rupture group and 75.5 (range: 67.2-78.79) in the control group.…”

“…The medial tibial depth is defined as the distance between the medial tibial plateau and the lowest point of the medial concavity [17,18]. The parameter r m represents the radius of the inferior circle of the posteromedial femoral condyle [17].…”