ACL Injury Study: Hip and Knee Biomechanics - PDF

Original Research Sagittal Plane Hip, Knee, and Ankle Biomechanics and the Risk of Anterior Cruciate Ligament Injury A Prospective Study Mari Leppänen,*† PhD, Kati Pasanen,† PT, PhD, Tron Krosshaug,‡ PhD, Pekka Kannus,§|| MD, PhD, Tommi Vasankari,§ MD, PhD, Urho M. Kujala,{ MD, PhD, Roald Bahr,‡ M...

Original Research Sagittal Plane Hip, Knee, and Ankle Biomechanics and the Risk of Anterior Cruciate Ligament Injury A Prospective Study Mari Leppänen,*† PhD, Kati Pasanen,† PT, PhD, Tron Krosshaug,‡ PhD, Pekka Kannus,§|| MD, PhD, Tommi Vasankari,§ MD, PhD, Urho M. Kujala,{ MD, PhD, Roald Bahr,‡ MD, PhD, Jarmo Perttunen,# PT, PhD, and Jari Parkkari,† MD, PhD Investigation performed at the Tampere Research Center of Sports Medicine, UKK Institute, Tampere, Finland Background: Stiff landings with less knee flexion and high vertical ground-reaction forces have been shown to be associated with an increased risk of anterior cruciate ligament (ACL) injury. The literature on the association between other sagittal plane measures and the risk of ACL injuries with a prospective study design is lacking. Purpose: To investigate the relationship between selected sagittal plane hip, knee, and ankle biomechanics and the risk of ACL injury in young female team-sport athletes. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 171 female basketball and floorball athletes (age range, 12-21 years) participated in a vertical drop jump test using 3-dimensional motion analysis. All new ACL injuries, as well as match and training exposure data, were recorded for 1 to 3 years. Biomechanical variables, including hip and ankle flexion at initial contact (IC), hip and ankle ranges of motion (ROMs), and peak external knee and hip flexion moments, were selected for analysis. Cox regression models were used to calculate hazard ratios (HRs) with 95% CIs. The combined sensitivity and specificity of significant test variables were assessed using a receiver operating characteristic (ROC) curve analysis. Results: A total of 15 noncontact ACL injuries were recorded during follow-up (0.2 injuries/1000 player-hours). Of the variables investigated, landing with less hip flexion ROM (HR for each 10 increase in hip ROM, 0.61 [95% CI, 0.38-0.99]; P <.05) and a greater knee flexion moment (HR for each 10-Nm increase in knee moment, 1.21 [95% CI, 1.04-1.40]; P ¼.01) was significantly associated with an increased risk of ACL injury. Hip flexion at IC, ankle flexion at IC, ankle flexion ROM, and peak external hip flexion moment were not significantly associated with the risk of ACL injury. ROC curve analysis for significant variables showed an area under the curve of 0.6, indicating a poor combined sensitivity and specificity of the test. Conclusion: Landing with less hip flexion ROM and a greater peak external knee flexion moment was associated with an increased risk of ACL injury in young female team-sport players. Studies with larger populations are needed to confirm these findings and to determine the role of ankle flexion ROM as a risk factor for ACL injury. Increasing knee and hip flexion ROMs to produce soft landings might reduce knee loading and risk of ACL injury in young female athletes. Keywords: anterior cruciate ligament; biomechanics; risk factors; female; team sports An anterior cruciate ligament (ACL) injury is one of the young female athletes, has still grown.20 Understanding most common and severe knee injuries among young ath- the cause of ACL injuries is an essential part of effective letes.1,20 While there is strong evidence on the effectiveness injury prevention,35 but it is so far incomplete.30 of training interventions to reduce the risk of ACL inju- A few prospective studies have examined the biomechan- ries,29 the incidence of such injuries, especially among ical risk factors for ACL injuries.12,16,18,26,31 Proposed bio- mechanical risk factors include knee valgus loading12 and The Orthopaedic Journal of Sports Medicine, 5(12), 2325967117745487 stiff landings with less peak knee flexion and high vertical DOI: 10.1177/2325967117745487 ground-reaction forces.12,18 However, the evidence gath- ª The Author(s) 2017 ered from these investigations is inconclusive,30 and more This open-access article is published and distributed under the Creative Commons Attribution - NonCommercial - No Derivatives License (http://creativecommons.org/ licenses/by-nc-nd/4.0/), which permits the noncommercial use, distribution, and reproduction of the article in any medium, provided the original author and source are credited. You may not alter, transform, or build upon this article without the permission of the Author(s). For reprints and permission queries, please visit SAGE’s website at http://www.sagepub.com/journalsPermissions.nav. 1 2 Leppänen et al The Orthopaedic Journal of Sports Medicine prospective studies that include hip and ankle variables, in Players with previous ACL injuries were eligible to partic- addition to knee variables, are needed. ipate if they were fully recovered from their previous There is a strong body of evidence showing that sagittal injury. Final participation was based on a written informed plane factors contribute to the ACL injury mecha- consent form from the player (including parental consent nism.7,13,23,33,36 Higher lower extremity joint flexion during for players aged