Medial Tibial Slope Determined by Plain Radiography Is Not Associated with Primary or Recurrent Anterior Cruciate Ligament Tears

Increased tibial slope may be associated with anterior cruciate ligament (ACL) injuries, although potential confounding effects from various patient characteristics and radiographic quantification methods have not been rigorously studied. The association of the slope of the lateral plateau with recurrent ACL injury after primary ACL reconstruction has recently been reported, but the role of medial slope is less well defined. The purpose of this study was to (1) assess medial tibial slope measurement reliability among examiners, (2) compare medial tibial slope values between patients undergoing primary ACL reconstruction, reinjured patients undergoing revision ACL reconstruction, and a control cohort with an intact ACL, (3) analyze if the medial tibial slope is an independent risk factor for noncontact ACL injury, and (4) assess how different anatomical references affect medial tibial slope values. A total of 206 patients were enrolled into one of three groups: (1) ACL-intact controls (CONTROL, n = 83), (2) first-time ACL-injured patients (PRIMARY, n = 77), and (3) patients undergoing revision ACL reconstruction (REVISION, n = 46). Three fellowship-trained sports medicine surgeons performed repeated measurements of plain lateral radiographs. The medial tibial slope was determined by three anatomical references: anterior tibial cortex (anterior tibial slope [ATS]), posterior tibial cortex (posterior tibial slope [PTS]), and the anatomical long axis of the tibia (composite tibial slope [CTS]). Substantial intra- and interobserver reliabilities were established by the intraclass correlation coefficient of 0.73 to 0.89. There was no difference in CTS, ATS, or PTS comparing the CONTROL, PRIMARY, and REVISION groups upon univariate analyses. Multivariable logistic regression model showed that none of the slope values was independently associated with ACL injury. The mean ATS for all 206 subjects was 4 and 8 degrees greater than the mean CTS and PTS, respectively. ATS correlated only moderately to PTS. We concluded that medial tibial slope measured on radiographs is not associated with primary or recurrent ACL injury, and has substantial variation and suboptimal correlation when using different anatomical references despite good inter- and intraobserver reliabilities.

Is Medial Tibial Slope Associated With Non-contact ACL Tears? An Analysis Of Primary And Revision Acl Reconstruction Patients

Objectives: Increased tibial slope (TS) may be associated with non-contact ACL injuries although potential confounding effects from various patient characteristics and radiographic quantification methods have not been rigorously studied. The association of TS with recurrent non-contact ACL injury after primary reconstruction is less defined. The purpose of this study was: 1) to assess the reliability and variability of TS values among different examiners, and 2) to compare TS between patients undergoing primary ACL reconstruction, re-injured patients undergoing revision ACL reconstruction, and an ACL-intact cohort. Methods: A total of 206 patients were prospectively enrolled in this single center, IRB-approved study that consisted of 3 groups: 1) ACL intact controls (CTRL, n=83), 2) first-time ACL injured patients from a non-contact mechanism (PRIM, n=77), and 3) patients with repeated non-contact ACL injury after primary ACL reconstruction (REV, n=46). Patients with prior knee surgery, radiographic signs of arthritis, chondral lesions ≥ grade 2, or insufficient radiographs were excluded. Repeated measurements of anterior and posterior TS were performed by 3 fellowship-trained sports medicine surgeons based on the previously described Utzschneider method that has a strong correlation to CT and MRI measurements. The anterior tibial slope (ATS) and posterior tibial slope (PTS) were measured to calculate an approximate mean medial tibial slope (MTS) based on the anatomic tibial axis. (Fig. 1). The intra- and inter-observer reliability were assessed by intra-class correlation coefficients (ICC). The MTS, ATS, PTS, age, BMI and sex distribution were compared among the three groups using one-way ANOVA with Tukey’s post hoc test and Chi-square test, respectively. The independent association of TS with ACL-intact controls (CTRL) vs. positive ACL injury (PRIM + REV) was assessed by multivariable logistic regression for MTS, ATS, and PTS, respectively. An a priori power analysis determined that 45 patients per group were needed to achieve a statistical power > 80% to detect a 1° difference (SD=3°) with α=0.05. Results: The ICC for intra- and inter-observer reliability in the calculation of TS ranged from 0.73-0.89 indicating substantial agreement. There was no significant difference in values for MTS, ATS, and PTS between the CTRL, PRIM and REV groups (p=0.42, 0.12, and 0.42, respectively). Patient age was highest in the CTRL group, followed by the REV, then PRIM groups (p<0.001) (Table 1). None of the TS values were independently associated with ACL injury based on multivariable logistic regression adjusted for age and sex. The mean ATS for all 206 subjects was 5° and 10° greater than that of the MTS and PTS, respectively (p < 0.001). ATS correlated only moderately to PTS (R2=0.49, p < 0.001). Conclusion: There is substantial intra- and inter-observer reliability in the radiographic assessment of medial tibial slope. Medial tibial slope was not associated with first time non-contact ACL tears or recurrent ACL graft tears undergoing reconstruction. [Table: see text]

The Effect of Medial Tibial Slope on Anterior Tibial Translation and Short-Term ACL Reconstruction Outcome

Background Increased tibial slope has been shown to be associated with higher anterior cruciate ligament (ACL) reconstruction failure rate. Little is known about the correlation of tibial slope and anterior tibial translation in ACL deficient and reconstructed knees as well as the correlation of tibial slope and ACL reconstruction outcome. Purpose/Hypothesis The purpose of this study was to investigate the correlation of tibial slope with anterior tibial translation and ACL reconstruction outcome. It is hypothesized that increased medial tibial slope is associated with increased anterior tibial translation in the ACL deficient knee. Medial tibial slope is neither expected to affect anterior tibial translation in the ACL reconstructed knee nor short-term ACL reconstruction outcome. Materials and Methods A cohort of 104 patients with unilateral isolated ACL deficiency undergoing hamstring ACL reconstruction by a single surgeon between 2002 and 2004 was followed up prospectively. Preoperative data were collected including patient demographics, time to surgery, subjective and objective International Knee Documentation Committee (IKDC) outcome scores, as well as manual maximum anterior tibial translation measured with the KT-1000 measuring instrument. Medial tibial slope was assessed on long lateral X-rays using the method described by Dejour and Bonnin (1994). Intraoperative data were collected including meniscal integrity; postoperative data were collected at 1-year follow-up including manual maximum anterior tibial translation (KT-1000 measured), and subjective and objective IKDC scores. Results A significant positive correlation was seen between medial tibial slope in ACL deficient knees and KT-1000–measured anterior tibial translation (r = 0.24; p = 0.003). The positive relationship increased when meniscal integrity was factored in (r = 0.33; p < 0.001). No significant correlation was seen between medial or lateral meniscal integrity and KT-1000–measured anterior tibial translation (r = −18; p = 0.06). No significant correlation was seen between KT-1000–measured anterior tibial translation and time to surgery. One year postoperatively, 82 patients were assessed, while 26 patients were lost to follow-up; no significant correlation was found between increased medial tibial slope and poor ACL reconstruction outcome measured by post-ACL reconstruction anterior tibial translation (KT-1000) or subjective and objective IKDC scores. Conclusion Increased medial tibial slope is associated with increased (KT-1000 measured) anterior tibial translation in ACL deficient knees. No significant correlation is found between increased medial tibial slope and poor short-term ACL reconstruction outcome.

Estimation of the posterior tibial slope on magnetic resonance images in Serbian population

Background/Aim. Preservation of an adequate posterior tibial slope (PTS) during total knee arthroplasty is crucial for the biomechanical stability and function of the knee joint. Studies that investigated anatomical features of the tibial plateau found significant gender and inter-population differences in all components of the PTS. The aim of this study was to establish reference values of PTS in Serbian population and to explore if there is any difference in the tibial plateau inclination between genders. Methods. We retrospectively reviewed 161 magnetic resonance images (MRIs) of the knee of adult patients examined in Medical Military Academy in Belgrade, Serbia, in a period from November 2011 to September 2014. Measurements of PTS components: medial tibial slope (MTS), lateral tibial slope (LTS), and coronal tibial slope (CTS) were performed through several steps, according to the suggestions in the recent literature. Obtained values for each tibial slope were compared between gender subgroups using appropriate statistical tests. Results. Mean values of each component of the posterior tibial slope for male vs. female subgroups were as follows: MTS 3.7? ? 2.8? vs. 5.1? ? 2.9?, LTS 4.2? ? 2.8? vs. 4.3? ? 2.7?, and CTS 3.9? ? 2.4? vs. 3.3? ? 1.9? respectively. The medial tibial slope was significantly higher in females than in males (p = 0.005). The mean value of the coronal tibial slope was greater in males without statistically significant difference (p = 0.105). Conclusion. This study demonstrated significant difference in MTS of the tibial plateau between males and females, being higher in the female subgroup.