Correlation of medial tibial slope and lateral tibial slope measured on radiographs and magnetic resonance imaging in patients with anterior cruciate ligament injury.

OBJECTIVES: The study aimed to investigate the correlation between medial tibial slope (MTS) and lateral tibial slope (LTS) on magnetic resonance imaging (MRI), MTS measured by different imaging, and the intra- and interobserver reliability of measurements between reviewers with gaps of experience over 10 years. PATIENTS AND METHODS: This retrospective study included 97 patients (93 males, 4 females; mean age: 30.8±8.3 years; range, 17 to 49 years) with anterior cruciate ligament (ACL) injuries who subsequently underwent double-bundle ACL reconstruction by a single surgeon between January 2005 and December 2014. The MTS was measured on lateral knee radiographs, and MTS and LTS were measured on MRIs. Three different reviewers, including a postgraduate year doctor, an orthopedic resident, and an attending orthopedic surgeon, performed the measurements. Each reviewer measured the slope of the same image three times. The correlations of MTS on radiographs and MTS/LTS on MRIs were calculated. Intra- and interobserver reliability were evaluated. RESULTS: The average MTS and LTS measured on MRI were not significantly different (6.4° and 6.9°, respectively; p=0.268) and exhibited a moderate positive correlation (r=0.544, p<0.001). The average MTS on radiographs was significantly greater than that on MRI (10.5° and 6.4°, respectively; p<0.001) with a low positive correlation (r=0.480, p<0.001). The intraobserver reliability of the postgraduate year doctor, the orthopedic resident, and the attending orthopedic surgeon were moderate to excellent. The interobserver reliability of MTS on radiographs was excellent (intraclass correlation coefficient [ICC]=0.925; p<0.001). The interobserver reliability of MTS on MRI as well as LTS on MRI was good (ICC=0.755 and 820, respectively; all p values <0.001). CONCLUSION: Average MTS and LTS measured on MRI in patients with ACL injury exhibited a moderate positive correlation. The average MTS measured on radiographs was significantly greater than that on MRI with a low positive correlation.

Enhanced reliability and time efficiency of deep learning-based posterior tibial slope measurement over manual techniques.

PURPOSE: Multifaceted factors contribute to inferior outcomes following anterior cruciate ligament (ACL) reconstruction surgery. A particular focus is placed on the posterior tibial slope (PTS). This study introduces the integration of machine learning and artificial intelligence (AI) for efficient measurements of tibial slopes on magnetic resonance imaging images as a promising solution. This advancement aims to enhance risk stratification, diagnostic insights, intervention prognosis and surgical planning for ACL injuries. METHODS: Images and demographic information from 120 patients who underwent ACL reconstruction surgery were used for this study. An AI-driven model was developed to measure the posterior lateral tibial slope using the YOLOv8 algorithm. The accuracy of the lateral tibial slope, medial tibial slope and tibial longitudinal axis measurements was assessed, and the results reached high levels of reliability. This study employed machine learning and AI techniques to provide objective, consistent and efficient measurements of tibial slopes on MR images. RESULTS: Three distinct models were developed to derive AI-based measurements. The study results revealed a substantial correlation between the measurements obtained from the AI models and those obtained by the orthopaedic surgeon across three parameters: lateral tibial slope, medial tibial slope and tibial longitudinal axis. Specifically, the Pearson correlation coefficients were 0.673, 0.850 and 0.839, respectively. The Spearman rank correlation coefficients were 0.736, 0.861 and 0.738, respectively. Additionally, the interclass correlation coefficients were 0.63, 0.84 and 0.84, respectively. CONCLUSION: This study establishes that the deep learning-based method for measuring posterior tibial slopes strongly correlates with the evaluations of expert orthopaedic surgeons. The time efficiency and consistency of this technique suggest its utility in clinical practice, promising to enhance workflow, risk assessment and the customization of patient treatment plans. LEVEL OF EVIDENCE: Level III, cross-sectional diagnostic study.

Correlation between higher lateral tibial slope and inferior long term subjective outcomes following single bundle anterior cruciate ligament reconstruction.

BACKGROUND: The impact of anatomical factors, such as the lateral tibial slope (LTS), on outcomes following anterior cruciate ligament (ACL) reconstruction is an area of growing interest. This study was led by the observation that patients with a higher LTS may have different recovery trajectories. HYPOTHESIS/PURPOSE: The purpose of this study was to investigate the correlation between a higher LTS and long term subjective outcomes following single-bundle ACL reconstruction. STUDY DESIGN: This study was designed as a retrospective cohort study. METHODS: The study comprised 138 patients who underwent single-bundle ACL reconstruction. The LTS was measured on preoperative radiographs. Patient-reported outcome measures (PROMs) were collected, which included the Lysholm Knee Score, UCLA Activity Score, IKDC Score, and Tegner Activity Score, over a mean follow-up duration of 137 months. RESULTS: A significant negative correlation was found between LTS and all measured PROMs (p < 0.001). The established cut-off value of LTS distinguishing between "Good" and "Fair" Lysholm scores was 8.35 degrees. Female patients have statistically significant higher LTS and lower PROMs scores than male. Patients with LTS greater than or equal to 8.35 had significantly lower PROMs, indicative of poorer functional and subjective outcomes. CONCLUSION: Our findings suggest that a higher LTS is associated with inferior subjective outcomes following single-bundle ACL reconstruction in long term. The LTS cut-off value of 8.35 degrees could potentially be used as a reference in preoperative planning and patient counseling. CLINICAL RELEVANCE: Understanding the relationship between LTS and ACL reconstruction outcomes could inform surgical planning and postoperative management. These findings highlight the need to consider anatomical variances, such as LTS, when assessing patient-specific risks and recovery expectations, contributing to the advancement of personalized care in sports medicine.

The increased lateral tibial slope may result in inferior long-term clinical outcome after DB-ACL reconstruction.

PURPOSE: To determine if there is a correlation between lateral tibial slope and long-term clinical results in patients who underwent double-bundle ACL reconstruction. METHODS: We retrospectively reviewed patients that received double-bundle ACL reconstruction at a single institution by a single surgeon from January 2011 to December 2014. All the magnetic resonance imaging were reviewed and lateral tibial slopes (LTS) were recorded by an experienced surgeon and rechecked by the other two authors of this study that specialized in orthopedic knee surgery. The relationship between PROMs measurement and lateral tibial slope were analyzed. The patients were then separated into two groups (LTS > 7.4° and < 7.4°) according to the previous study. RESULTS: A total of 119 patients were enrolled in this study. All enrolled patients were followed for at least 8 years. The PROMS result were negatively correlated with the lateral tibial slope (p values all < 0.001). The patients with high lateral tibial slope had significantly lower PROMS values (Lysholm 94.26 ± 5.61 vs 80.15 ± 8.28, p = 0.013; IKDC 82.99 ± 4.55 vs 70.09 ± 7.15, p = 0.003; Tegner 9.32 ± 0.95 vs 6.85 ± 1.99, p < 0.001). Finally, the LTS cutoff value between patients with "Good" and "Fair" Lysholm score in our study was 7.55 degrees. CONCLUSIONS: Patients with high lateral tibial slope may result in inferior long-term subjective outcomes. The using of double-bundle ACL reconstruction along cannot overcome the negative impact caused by steep lateral tibial slope. A lateral tibial slope of 7.55° may be used as a cut-off for a good clinical outcome. LEVEL OF EVIDENCE: III retrospective comparative prognostic trial.