Lateral meniscal slope negatively affects post-operative anterior tibial translation at 1 year after primary anterior cruciate ligament reconstruction

Abstract

Purpose The aim of this study was to assess the correlation between posterior tibial slope and meniscal slope over postoperative anterior tibial translation during the first 18 months after primary anterior cruciate ligament (ACL) reconstruction. The main hypothesis was that PTS and MS would be positively correlated with post-operative ATT-SSD after ACL reconstruction. Methods Patients (28 males and 15 females) with confirmed ACL tears were selected from an in-house registry and included if they were over 16 years old, had primary ACL-reconstruction and healthy contralateral knee. Patients meeting one of the following criteria were excluded: previous knee surgeries, intraarticular fractures, associated ligamentous lesions, previous or concomitant meniscectomy or extraarticular procedures. Lateral posterior tibial slope, medial posterior tibial slope, lateral meniscal slope and medial meniscal slope were measured using preoperative MRIs. The side-to-side-difference in anterior tibial translation was evaluated 9-18 months postoperatively. Results Forty-three patients were included, (28 males/15 females; mean age 25 ± 8 years). Mean postoperative anterior tibial translation was 1.0 ± 1.1 mm at a mean time of 12 ± 1 months. Mean slope values were: lateral posterior tibial slope 4.7° ± 2.2°, medial posterior tibial slope 4.0° ± 2.8°, lateral meniscal slope 3.0° ± 2.2° and medial meniscal slope 2.0° ± 2.8°. The anterior tibial translation was significantly correlated with lateral meniscal slope (r = 0.63; p < 0.01). For each 1° increase in lateral meniscal slope, a 0.3 mm 95% CI [0.2, 0.4] (p < 0.01) increase in anterior tibial translation was observed. A lateral meniscal slope greater or equal to 4.0° was estimated as optimal threshold for increased risk of abnormal side-to-side difference in postoperative anterior tibial translation (≥ 1.2 mm). Conclusion The lateral meniscal slope was positively correlated to side-to-side difference in anterior tibial translation after primary ACL reconstruction. A lateral meniscal slope greater or equal to 4.0° was detected as threshold for an increased risk of abnormal side-to-side difference in postoperative anterior tibial translation in patients who underwent primary ACL reconstruction. This confirms that soft tissue slopes have an impact on the outcomes after reconstructive surgery. Level of evidence III.

Age and Bone Bruise Patterns Predict Tear Location in the Anterior Cruciate Ligament

“… 27 In particular, a steeper lateral tibial slope has been associated with increased ATT in the ACL-injured knee, although the results have varied widely. 16 , 28 Because the ACL is the primary passive restraint against ATT, increased translation has been shown to induce greater ACL loading stress subsequently. 29 Similarly, a decreased LFC index has been suggested to be associated with increased gliding of the LFC over the LTP, thereby resulting in a greater pivoting mechanism and increased ACL loading stress.…”

“…To assess potential anatomic risk factors, previously recognized MRI risk factors associated with ACL injury were analyzed, including the notch width index ( Fig 2 A), 12 notch angle ( Fig 2 A), femoral notch morphology ( Fig 2 B), 13 alpha angle, 14 posterior tibial slope ( Fig 3 ), 15 meniscal slope ( Fig 3 ), 16 and LFC index, 7 as described in Table 1 . All measurement methods have previously shown excellent reproducibility (intraclass correlation coefficient range, 0.89-0.99) 7 , 14 , 17 and were performed by an experienced orthopaedic research fellow (H.D.V.).…”

High-grade pivot-shift phenomenon after anterior cruciate ligament injury is associated with asymmetry of lateral and medial compartment anterior tibial translation and lateral meniscus posterior horn tears

“…The value of ATT is usually measured on MRI [29, 34], and therefore, L‐ATT and M‐ATT can be obtained. In some patients who underwent ACL injury, the L‐ATT and M‐ATT were not always consistent, and the L‐ATT was usually greater than the M‐ATT in most cases [20].…”

Posterior tibial slope and meniscal slope correlate with in vivo tibial internal rotation during running and drop jump

“…They found that a greater lateral MS may indicate a greater risk of injury, although there was no association between medial or lateral PTS and ACL injury [17]. Tradati et al investigated the relationship between MS and ATT using MRI and a motorized laximeter in 43 patients 1 year after ACL reconstruction [34]. They reported that ATT was significantly correlated with lateral MS ( r = 0.63; P < 0.01).…”

“…Sample size was based upon variability in knee AP translation and knee rotation during dynamic activities as measured using dynamic biplane radiography (DBR) [11], and previously reported variability in tibial [27] and meniscal slope [34]. Given 38 knees, this study was powered to detect associations between kinematics and anatomy that have effect sizes from medium to large [7] ( ρ = 0.46 to 0.52 based upon smallest and largest reported variabilities, respectively).…”