2023 ISAKOS Biennial Congress ePoster
Steeper Lateral Posterior Tibial Slope And Greater Lateral-Medial Slope Asymmetry are Associated With Greater Preoperative Pivot-Shift In Anterior Cruciate Ligament Injury
Kiminari Kataoka, MD, Kobe, Hyogo JAPAN
Kanto Nagai, MD, PhD, Kobe, Hyogo JAPAN
Yuichi Hoshino, MD, PhD, Kobe, Hyogo JAPAN
Masashi Shimabukuro JAPAN
Kyohei Nishida , MD, PhD, Kobe, Hyogo JAPAN
Noriyuki Kanzaki, MD, PhD, Kobe, Hyogo JAPAN
Takehiko Matsushita, MD, PhD, Kobe, Hyogo JAPAN
Ryosuke Kuroda, MD, PhD, Kobe, Hyogo JAPAN
Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Hyogo, JAPAN
FDA Status Cleared
Summary
The present study shows that steeper lateral posterior tibial slope and greater lateral-medial slope asymmetry were correlated with greater preoperative tibial acceleration during the pivot-shift test in ACL-injured knees.
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Abstract
Background
In anterior cruciate ligament (ACL)-injured knees, the cause of the spectrum of anterolateral rotatory knee laxity is multifactorial: the degree or chronicity of the injury to the ACL; injury to secondary knee stabilizers; bony morphology; as well as patient characteristics. Morphological factors have been attracting increased attention as important factors for unfavorable knee kinematics and ACL injury in recent years. Especially, steeper posterior tibial slope (PTS) has been recognized as a potential risk factor for ACL injury and ACL graft failure. In terms of anterolateral rotatory knee laxity, several studies have shown that steeper PTS is associated with a high-grade pivot-shift; however, an association between PTS and preoperative pivot-shift has not been fully elucidated.
Objectives:
To investigate the association between PTS and preoperative pivot-shift phenomenon in ACL-injured knees. It was hypothesized that steeper lateral PTS and greater lateral-to-medial PTS asymmetry would be associated with greater tibial acceleration during the pivot-shift test which was evaluated with an electromagnetic measurement system (EMS).
Methods
A retrospective analysis of prospectively collected data was performed, and fifty unilateral ACL-injured patients (mean age: 28.0±11.4 years, male/female: 29/21) who underwent ACL reconstruction were included in the present study. Patients with a history of injury to the ipsilateral knee joint, concomitant ligament injuries with ACL injury, and/or more than one year from injury to surgery, were excluded. The pivot-shift test was performed preoperatively under general anesthesia using an EMS, and tibial acceleration (m/s2) during the posterior reduction of the tibia was measured as previously reported. Medial and lateral PTS (°) was measured respectively using high-resolution CT images which were taken approximately two weeks after the surgery, as previously reported. The lateral-medial slope asymmetry was calculated by subtracting medial PTS from lateral PTS (lateral-medial PTS). Pearson correlation analysis was performed to evaluate the correlation between each PTS parameter (medial PTS, lateral PTS, and lateral-medial slope asymmetry) and tibial acceleration during the pivot-shift test. The level of significance was set at p < 0.05.
Results
The medial PTS was 4.9 ± 2.0° (mean ± standard deviation), and the lateral PTS was 5.2 ± 1.9°. The lateral-medial slope asymmetry was 0.3 ± 1.6° (range: -2.9 to 3.8). The tibial acceleration during the pivot-shift test in the ACL-injured knee was 1.6 ± 0.1 m/s2. Preoperative tibial acceleration was positively correlated with lateral PTS (r = 0.436, p < 0.01), and lateral-medial slope asymmetry (r = 0.443, p < 0.01), while no significant correlation was found between preoperative tibial acceleration and medial PTS (r = 0.06, p = 0.70).
Conclusions
The main finding of the present study was that preoperative tibial acceleration during the pivot-shift test was positively correlated with lateral PTS and lateral-medial slope asymmetry in ACL-injured knees. This suggests that bony morphology of the tibial plateau is associated with preoperative anterolateral rotatory knee laxity in ACL injury. Surgeons should be aware that lateral PTS, as well as lateral-medial slope asymmetry, may affect preoperative anterolateral rotatory knee laxity in ACL injury.