Background:
Knee joint geometry has been associated with risk of suffering an anterior cruciate ligament (ACL) injury; however, few studies have utilized multivariate analysis to investigate how ...different aspects of knee joint geometry combine to influence ACL injury risk.
Hypotheses:
Combinations of knee geometry measurements are more highly associated with the risk of suffering a noncontact ACL injury than individual measurements, and the most predictive combinations of measurements are different for males and females.
Study Design:
Case-control study; Level of evidence, 3.
Methods:
A total of 88 first-time, noncontact, grade III ACL-injured subjects and 88 uninjured matched-control subjects were recruited, and magnetic resonance imaging data were acquired. The geometry of the tibial plateau subchondral bone, articular cartilage, and meniscus; geometry of the tibial spines; and size of the femoral intercondylar notch and ACL were measured. Multivariate conditional logistic regression was used to develop risk models for ACL injury in females and males separately.
Results:
For females, the best fitting model included width of the femoral notch at its anterior outlet and the posterior-inferior–directed slope of the lateral compartment articular cartilage surface, where a millimeter decrease in notch width and a degree increase in slope were independently associated with a 50% and 32% increase in risk of ACL injury, respectively. For males, a model that included ACL volume and the lateral compartment posterior meniscus to subchondral bone wedge angle was most highly associated with risk of ACL injury, where a 0.1 cm3 decrease in ACL volume (approximately 8% of the mean value) and a degree decrease in meniscus wedge angle were independently associated with a 43% and 23% increase in risk, correspondingly.
Conclusion:
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.
Background:
There is an emerging consensus that increased posterior-inferior directed slope of the subchondral bone portion of the tibial plateau is associated with increased risk of suffering an ...anterior cruciate ligament (ACL) injury; however, most of what is known about this relationship has come from unmatched case-control studies. These observations need to be confirmed in more rigorously designed investigations.
Hypothesis:
Increased posterior-inferior directed slope of the medial and lateral tibial plateaus are associated with increased risk of suffering a noncontact ACL injury.
Study Design:
Case-control study; Level of evidence, 3.
Methods:
In sum, 176 athletes competing in organized sports at the college and high school levels participated in the study: 88 suffering their first noncontact ACL injury and 88 matched controls. Magnetic resonance images were acquired, and geometry of the subchondral bone portion of the tibial plateau was characterized on each athlete bilaterally by measuring the medial and lateral tibial plateau slopes, coronal tibial slope, and the depth of the medial tibial plateau. Comparisons between knees of the same person were made with paired t tests, and associations with injury risk were assessed by conditional logistic regression analysis of ACL-injured and control participants.
Results:
Controls exhibited side-to-side symmetry of subchondral bone geometry, while the ACL-injured athletes did not, suggesting that the ACL injury may have changed the subchondral bone geometry. Therefore, the uninjured knees of the ACL-injured athletes and the corresponding limbs of their matched controls were used to assess associations with injury risk. Analyses of males and females as a combined group and females as a separate group showed a significant association between ACL injury risk and increased posterior-inferior directed slope of the lateral tibial plateau slope. This relationship was not apparent when males were analyzed as a group. Multivariate analyses indicated that these results were independent of the medial tibial plateau slope, coronal tibial slope, and depth of the medial tibial plateau, which were not associated with ACL injury.
Conclusion:
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.
Background:
The morphometric characteristics of the anterior cruciate ligament (ACL) and the femoral intercondylar notch within which it resides have been implicated as risk factors for injuries to ...this important stabilizer of the knee. Prior research has produced equivocal results with differing methodologies, and consequently, it is unclear how these characteristics affect the injury risk in male and female patients.
Hypothesis:
The morphometric characteristics of the ACL and femoral intercondylar notch are individually and independently associated with the risk of suffering a noncontact ACL injury, and these relationships are different in male and female patients.
Study Design:
Case-control study; Level of evidence, 3.
Methods:
Magnetic resonance imaging scans of the bilateral knees were obtained on 88 case-control pairs (27 male, 61 female) matched for age, sex, and participation on the same sports team. Patients had suffered a grade III, first-time, noncontact ACL tear. The femoral notch width at 4 locations, the thickness of the bony ridge at the anteromedial outlet of the femoral notch, the femoral notch volume, ACL volume, and ACL cross-sectional area were measured.
Results:
Multivariate analysis of combined data from male and female patients revealed that decreased ACL volume (odds ratio OR, 0.829), decreased femoral notch width (OR, 0.700), and increased bony ridge thickness at the anteromedial outlet of the femoral notch (OR, 1.614) were significant independent predictors of an ACL injury. Separate analyses of male and female patients indicated that the femoral notch ridge may be more strongly associated with a risk in female patients, while ACL volume is more strongly associated with a risk in male patients. However, statistical analysis performed with an adjustment for body weight strengthened the association between ACL volume and the risk of injuries in female patients.
Conclusion:
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.
Background:
Multivariate analysis that identifies the combination of risk factors associated with anterior cruciate ligament (ACL) trauma is important because it provides insight into whether a ...variable has a direct causal effect on risk or an indirect effect that is mediated by other variables. It can also reveal risk factors that might not be evident in univariate analyses; if a variable’s effect is moderated by other variables, its association with risk may be apparent only after adjustment for the other variables. Most important, multivariate analyses can identify combinations of risk factors that are more predictive of risk than individual risk factors.
Hypothesis:
A diverse combination of risk factors predispose athletes to first-time noncontact ACL injury, and these relationships are different for male and female athletes.
Study Design:
Case-control study; Level of evidence, 3.
Methods:
Athletes competing in organized sports at the high school and college levels participated in this study. Data from injured subjects (109 suffering an ACL injury) and matched controls (227 subjects) from the same athletic team were analyzed with multivariate conditional logistic regression to examine the effects of combinations of variables (demographic characteristics, joint laxity, lower extremity alignment, strength, and personality traits) on the risk of suffering their first ACL injury and to construct risk models.
Results:
For male athletes, increases in anterior-posterior displacement of the tibia relative to the femur (knee laxity), posterior knee stiffness, navicular drop, and a decrease in standing quadriceps angle were jointly predictive of suffering an ACL injury. For female athletes the combined effects of having a parent who had suffered an ACL injury and increases in anterior-posterior knee laxity and body mass index were predictive of ACL injury.
Conclusion:
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.
Background:
The lateral femoral condyle index (LFCI)—a recently developed measure of the sphericity of the lateral femoral condyle—was reported to be a risk factor for anterior cruciate ligament ...(ACL) injury. However, issues have been raised regarding how the index was measured and regarding the patient group and the knee in which it was measured.
Purpose:
To investigate the association between the LFCI and the risk of sustaining a primary, noncontact ACL injury, and to examine whether this association was moderated by the posterior-inferior–directed slope of the lateral tibial plateau.
Study Design:
Cross-sectional study; Level of evidence, 3.
Methods:
A secondary analysis was conducted of deidentified magnetic resonance images of the uninjured knees of 86 athletes with ACL injury and the corresponding knees of 86 control athletes, matched for sports team, sex, and age. From those images, we measured the LFCI and the posterior-inferior–directed slope of the middle region articular cartilage surface of the tibial plateau’s lateral compartment. Conditional logistic regressions were performed to determine whether the LFCI was significantly associated with ACL injury risk and whether the lateral tibial compartment middle cartilage slope moderated this association. Data were analyzed for female and male participants separately as well as for both groups combined.
Results:
The LFCI was not found to be significantly associated with experiencing a primary, noncontact ACL injury for all analyses. The lateral tibial slope measure was not found to moderate the association between the LFCI and ACL injury. A conditional logistic regression analysis using the LFCI data of the injured knees, instead of the uninjured knees, of the participants with ACL injury revealed that the LFCI was significantly associated with ACL injury.
Conclusion:
In this population of athletically active female and male participants, the LFCI was not found to be a risk factor for noncontact ACL injury, regardless of the geometric features of the lateral tibial slope.
Background:
Recently developed multivariate sex-specific statistical models can predict anterior cruciate ligament (ACL) injury risk using various knee anatomic factors. However, screening tools able ...to identify individuals at an increased injury risk are unlikely to be developed based on these models, given that sophisticated and time-consuming methods were used to measure those factors on research-grade resolution magnetic resonance images (MRIs).
Purpose:
To determine whether simpler methods, amenable to using clinical-grade resolution MRIs, can identify the same knee anatomic factors previously found to contribute to ACL injury risk using sophisticated methods and research-grade resolution images.
Study Design:
Cohort study (diagnosis); Level of evidence, 2.
Methods:
High-resolution 3-dimensional MRIs previously acquired from 87 patients with primary, noncontact, grade III ACL injury and 87 uninjured matched control participants for a series of published studies were downgraded to clinical-grade resolution images. The 4 knee anatomic factors found to contribute to ACL injury risk in women and in men in these published studies—femoral intercondylar notch width at the anterior outlet of the ACL (NW_O), posterior-inferior directed slope of the middle region articular cartilage surface of the tibial plateau’s lateral compartment (LatTibMCS), ACL volume, and tibial plateau’s lateral compartment posterior meniscus to subchondral bone wedge angle (LatTibMBA)—were measured using clinical-grade resolution MRI-based methods. Stepwise multivariate conditional logistic regressions were used to identify the combinations of factors most highly associated with an ACL injury risk in women and men separately.
Results:
The multivariate model that best predicted ACL injury risk in the female participants included the LatTibMCS and the NW_O. For the male participants, this model included the ACL volume and the LatTibMBA. These results corroborate the previously published results that reported models with the same knee anatomic factors to best predict injury risk in this group of young women and men.
Conclusion:
Simpler methods using MRIs downgraded to a clinical-grade resolution can identify the same knee anatomic factors previously found to significantly contribute to ACL injury risk using sophisticated methods and research-grade resolution MRIs.
Anterior cruciate ligament injury and reconstruction (ACLR) affects articular cartilage thickness profiles about the tibial, femoral, and patellar surfaces; however, it's unclear whether the ...magnitudes of change in cartilage thickness, as well as the locations and areas over which these changes occur, differ between males and females. This is important to consider as differences exist between the sexes with regard to knee biomechanics, patellofemoral pain, and anatomic alignment, which influence risk of an index and repeated injury. Subjects underwent ACLR with a bone‐patella tendon‐bone autograft. At 4‐year follow‐up, they had asymptomatic knees; however, significant ACL injured‐to‐contralateral normal knee differences in articular cartilage thickness values were observed. Both thickening and thinning of cartilage occurred about the tibiofemoral and patellofemoral joints, relative to matched control subjects with normal knees. Further, the location of the areas and magnitudes of thickening and thinning were different between females and males. Thickening (swelling) of articular cartilage is an early finding associated with the onset of posttraumatic osteoarthritis (PTOA). Therefore, the increases in cartilage thickness that were observed in this cohort may represent early signs of the onset of PTOA that occur prior to the patient developing symptoms and radiographic evidence of this disease. The different locations of areas that underwent a change in cartilage thicknesses between males and females suggest that each sex responds differently to knee ligament trauma, reconstruction, rehabilitation, and return to activity, and indicates that sex‐specific analysis should be utilized in studies of PTOA.
This Institutional Review Board–approved pilot study attempted to detect the correlation between ultrasound shear wave elastographic measures and tendon loads. Five male fresh‐frozen cadaveric ...Achilles tendons were loaded in 10‐N increments from 0 to 60 N. Shear wave velocity measurements within each Achilles tendon were obtained at each load in longitudinal and transverse orientations. Shear wave velocity measurements were correlated with tendon tension on both longitudinal and transverse plane imaging and showed moderate and strong positive correlation coefficients, respectively. Of note, limitations of the clinically available shear wave elastographic technology for measuring high velocities exist.
Finite element (FE) models to evaluate the burden placed on the interaction between total ankle arthroplasty (TAA) implants and the bone often rely on peak axial forces. However, the loading ...environment of the ankle is complex, and it is unclear whether peak axial forces represent a challenging scenario for the interaction between the implant and the bone. Our goal was to determine how the loads and the design of the fixation of the tibial component of TAA impact the interaction between the implant and the bone. To this end, we developed a framework that integrated robotic cadaveric simulations to determine the ankle kinematics, musculoskeletal models to determine the ankle joint loads, and FE models to evaluate the interaction between TAA and the bone. We compared the bone–implant micromotion and the risk of bone failure of three common fixation designs for the tibial component of TAA: spikes, a stem, and a keel. We found that the most critical conditions for the interaction between the implant and the bone were dependent on the specimen and the fixation design, but always involved submaximal forces and large moments. We also found that while the fixation design influenced the distribution and the peak value of bone–implant micromotion, the amount of bone at risk of failure was specimen dependent. To account for the most critical conditions for the interaction between the implant and the bone, our results support simulating multiple specimens under complex loading profiles that include multiaxial moments and span entire activity cycles.
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