Combinations of knee joint geometry measurements provided more information about the risk of noncontact ACL injury than individual measures, and the aspects of geometry that best explained the relationship between knee geometry and the risk of injury were different between males and females. Consequently, a female with both a decreased femoral notch width and an increased posterior-inferior-directed lateral compartment tibial articular cartilage slope combined or a male with a decreased ACL volume and decreased lateral compartment posterior meniscus angle were most at risk for sustaining an ACL injury.

Morphometric features of both the ACL and femoral notch combine to influence the risk of suffering a noncontact ACL injury. When included together in a multivariate model that adjusts for body weight, the effects of the morphometric measurements are similar in male and female patients. If body weight is not taken into consideration, ACL volume is not associated with a risk in female patients.

There is a 21.7% increased risk of noncontact ACL injury with each degree increase of the lateral tibial plateau slope among females but not among males. The medial tibial plateau slope, coronal tibial slope, and depth of the medial tibial plateau were not associated with risk of injury for females or males.

Tibial plateau subchondral bone geometry has been associated with the risk of sustaining a non-contact ACL injury; however, little is known regarding the influence of the meniscus and articular cartilage interface geometry on risk. We hypothesized that geometries of the tibial plateau articular cartilage surface and meniscus were individually associated with the risk of non-contact ACL injury. In addition, we hypothesized that the associations were independent of the underlying subchondral bone geometry. MRI scans were acquired on 88 subjects that suffered non-contact ACL injuries (27 males, 61 females) and 88 matched control subjects that were selected from the injured subject's teammates and were thus matched on sex, sport, level of play, and exposure to risk of injury. Multivariate analysis of the female data revealed that increased posterior-inferior directed slope of the middle articular cartilage region and decreased height of the posterior horn of the meniscus in the lateral compartment were associated with increased risk of sustaining a first time, non-contact ACL injury, independent of each other and of the slope of the tibial plateau subchondral bone. No measures were independently related to risk of non-contact ACL injury among males. ß 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32: 1487-1494, 2014. Injuries to the anterior cruciate ligament (ACL) of the knee are often immediately debilitating and can lead to post-traumatic osteoarthritis (PTOA) regardless of whether the ACL injuries are treated with surgical intervention or rehabilitation alone.1 Since current treatment options are ineffective in preventing PTOA, recent research has focused on reducing the incidence of ACL injuries. To achieve this it is necessary to thoroughly understand the risk factors for ACL injury, so that appropriate interventions can be developed and targeted at those most at risk. Risk factors for ACL injury are multifactorial and may be different for males and females.2 A few identified risk factors, such as neuromuscular control, are modifiable and may be intervened upon. Others risk factors, such as knee geometry, are not modifiable but may play a critical role in identifying individuals at increased risk for ACL injury who may benefit from alternative preventive strategies.Tibial plateau subchondral bone geometry has been associated with knee biomechanics and ACL strain values, which influence ACL injury risk. Research has shown that increased posterior-inferior directed slope of the tibial plateau subchondral bone is associated with increased anterior translation of the tibia relative to the femur 3 and increased ACL strain values 4,5 in response to compressive loading of the knee. In addition, this increased posteriorinferior directed slope of the subchondral bone, primarily in the lateral compartment and in females, is associated with an increased risk of suffering an ACL injury. [6][7][8][9][10] While previous reports have focused on analyses of subchondral bone ...

Measurements of tibial plateau subchondral bone and articular cartilage slope have been associated with the risk of suffering anterior cruciate ligament (ACL) injury. Such single-plane measures of the tibial plateau may not sufficiently characterize its complex, three-dimensional geometry and how it relates to knee injury. Further, the tibial spines have not been studied in association with the risk of suffering a non-contact ACL injury. We questioned whether the geometries of the tibial spines are associated with noncontact ACL injury risk, and if this relationship is different for males and females. Bilateral MRI scans were acquired on 88 ACLinjured subjects and 88 control subjects matched for sex, age and sports team. Medial and lateral tibial spine geometries were characterized with measurements of length, width, height, volume and anteroposterior location. Analyses of females revealed no associations between tibial spine geometry and risk of ACL injury. Analyses of males revealed that an increased medial tibial spine volume was associated with a decreased risk of ACL injury (OR ¼ 0.667 per 100 mm 3 increase). Smaller medial spines could provide less resistance to internal rotation and medial translation of the tibia relative to the femur, subsequently increasing ACL strains and risk of ACL injury. ß

Multivariate models provided more information about ACL injury risk than individual risk factors. Both male and female risk models included increased anterior-posterior knee laxity as a predictor of ACL injury but were otherwise dissimilar.

The geometric risk factors for ACL graft rupture are different for males and females. For females, a decreased femoral intercondylar notch width and a decreased height of the posterior medial meniscus were risk factors for ACL graft rupture that have also been found to be risk factors for first-time injury. There were no risk factors in common between ACL graft injury and first-time ACL injury for males.

The purpose of this study was to determine if geometry of the articular surfaces of the tibial plateau is associated with non-contact anterior cruciate ligament (ACL) injury. This was a longitudinal cohort study with a nested case-control analysis. Seventyeight subjects who suffered a non-contact ACL tear and a corresponding number of controls matched by age, sex, and sport underwent 3 T MRI of both knees. Surface geometry of the tibial articular cartilage was characterized with polynomial equations and comparisons were made between knees on the same person and between ACL-injured and control subjects. There was no difference in surface geometry between the knees of the control subjects. In contrast, there were significant differences in the surface geometry between the injured and normal knees of the ACL-injured subjects, suggesting that the ACL injury changed the cartilage surface profile. Therefore, comparisons were made between the uninjured knees of the ACL-injured subjects and the corresponding knees of their matched controls and this revealed significant differences in the surface geometry for the medial (p < 0.006) and lateral (p < 0.001) compartments. ACL-injured subjects tended to demonstrate a posterior-inferior directed orientation of the articular surface relative to the long axis of the tibia, while the control subjects were more likely to show a posterior-superior directed orientation. Severe knee injury, such as an anterior cruciate ligament (ACL) disruption, is often immediately disabling and has been associated with the early onset of post-traumatic osteoarthritis regardless of whether surgical or non-surgical treatment is chosen.1,2 This has motivated studies that have focused on identifying the variables associated with increased risk of ACL injury, so that prevention strategies can be developed and those at increased risk can be identified and targeted for intervention. 3During the process of suffering an ACL injury, the geometry of the articular surfaces of the knee is important in controlling the biomechanical response of the tibiofemoral joint and ACL. 4,5 For example, there appears to be a consensus forming in the literature that individuals who are at increased risk of suffering non-contact ACL disruptions have increased posteriorinferior directed slopes of the subchondral bone portion of their tibial plateaus compared to uninjured controls. [6][7][8][9][10][11][12][13][14][15][16] This relationship is important because the magnitude of ACL strain values produced by impulsive loading of the knee during common sportsrelated movements such as jump landings are directly related to the posterior-inferior directed slope of the subchondral bone of the proximal tibia. 4,17,18 Most of what is known about the relationship between the risk of suffering non-contact ACL injury and joint geometry has come from studies of the underlying subchondral bone of the tibia plateau; however, the large inter-segmental forces that are transmitted between the femur and tibia occur across the surface o...