Relationship of knee shear force and extensor moment on knee translations in females performing drop landings: a biplane fluoroscopy study

Empirical joint contact mechanics: A comprehensive review

Empirical joint contact mechanics measurement (EJCM; e.g. contact area or force, surface velocities) enables critical investigations of the relationship between changing joint mechanics and the impact on surface-to-surface interactions. In orthopedic biomechanics, understanding the changes to cartilage contact mechanics following joint pathology or aging is critical due to its suggested role in the increased risk of osteoarthritis (OA), which might be due to changed kinematics and kinetics that alter the contact patterns within a joint. This article reviews and discusses EJCM approaches that have been applied to articulating joints such that readers across different disciplines will be informed of the various measurement and analysis techniques used in this field. The approaches reviewed include classical measurement approaches (radiographic and sectioning, dye staining, casting, surface proximity, and pressure measurement), stereophotogrammetry/motion analysis, computed tomography (CT), magnetic resonance imaging (MRI), and high-speed videoradiography. Perspectives on approaches to advance this field of EJCM are provided, including the value of considering relative velocity in joints, tractional stress, quantification of joint contact area shape, consideration of normalization techniques, net response (superposition) of multiple input variables, and establishing linkages to regional cartilage health status. EJCM measures continue to provide insights to advance our understanding of cartilage health and degeneration and provide avenues to assess the efficacy and guide future directions of developing interventions (e.g. surgical, biological, rehabilitative) to optimize joint's health and function long term.

Advances in the Application of the Dual Fluoroscopic Imaging System in Sports Medicine: A Literature Review

The dual fluoroscopic imaging system (DFIS) is a new non-invasive motion analysis system that does not interfere with movement, has high precision and repeatability and is not affected by the errors caused by the relative movement of skin and soft tissues. DFIS has been recently used in the field of sports medicine. This narrative review focuses on relevant literature on the origin, development and mechanism of action of DFIS and summarises the application of DFIS in injury and rehabilitation treatment, such as the reliability of test results; the position relationships of bony structures in the shoulder, lumbar spine, knee joint and ankle joint during exercise and its six degree-of-freedom (6DOF) movement to calculate cartilage deformation, contact area/trajectory and ligament strain. This article puts forward the problems encountered in practice that need to be solved and looks forward to the future applications of DFIS in the field of sports, especially in injury prevention and treatment.

An exploratory study of the use of ultrasound in the measurement of anterior tibial translation under gastrocnemius muscle stimulation

Gastrocnemius' role as an agonist or antagonist of the anterior cruciate ligament (ACL) is not well understood. This study explored the use of ultrasound imaging to investigate how gastrocnemius stimulation levels influenced anterior tibial translation. The gastrocnemii of 10 participants were stimulated to four different levels using electrical muscle stimulation. The quadriceps were co-activated at a fixed level. Anterior tibial translation was determined using ultrasound imaging. Intraclass correlation coefficient [ICC (2,1)] was used to assess the intra-rater reliability over two sessions. Intra-rater reliability was good at rest and under most muscle stimulation levels (ICC = 0.84 to 0.92), and moderate with the lowest (ICC = 0.71) and highest stimulation (ICC = 0.61). While anterior tibial translation was not significantly different across simulation levels, ultrasound imaging recorded the anterior movement of the tibia as the gastrocnemius was activated, thus supporting gastrocnemius' role as an antagonist of the ACL.

Exploring the Justifications for Selecting a Drop Landing Task to Assess Injury Biomechanics: A Narrative Review and Analysis of Landings Performed by Female Netball Players

When assessing biomechanics in a laboratory setting, task selection is critical to the production of accurate and meaningful data. The injury biomechanics of landing is commonly investigated in a laboratory setting using a drop landing task. However, why this task is so frequently chosen is unclear. Therefore, this narrative review aimed to (1) identify the justification/s provided within the published literature as to why a drop landing task was selected to investigate the injury biomechanics of landing in sport and (2) use current research evidence, supplemented by a new set of biomechanical data, to evaluate whether the justifications are supported. To achieve this, a comprehensive literature search using Scopus, PubMed, and SPORTDiscus online databases was conducted for studies that had collected biomechanical data relating to sport injuries using a drop landing task. In addition, kinematic and kinetic data were collected from female netball players during drop landings and maximum-effort countermovement jumps from the ground to grab a suspended ball. The literature search returned a total of 149 articles that were reviewed to determine the justification for selecting a drop landing task. Of these, 54% provided no explicit justification to explain why a drop landing task was chosen, and 15% stated it was selected because it had been used in previous research. Other reasons included that the drop landing provides high experimental control (16%), is a functional sports task (11%), and is a dynamic task (6%). Evidence in the literature suggests that the biomechanical data produced with drop landings may not be as externally valid as more sport-specific tasks. Biomechanical data showed that the drop landing may not control center of mass fall height any better than maximum-effort countermovement jumps from the ground. Further, the frequently used step-off technique to initiate drop landings resulted in kinematic and kinetic asymmetries between lower limbs, which would otherwise be symmetrical when performing a countermovement jump from the ground. Researchers should consider the limitations of a drop landing task and endeavor to improve the laboratory tasks used to collect biomechanical data to examine the injury biomechanics of landing.

Lower extremity variability changes with drop-landing height manipulations

Landing is a common lower extremity injury mechanism in sport, with potential connections to movement control accessed through variability measures. We investigated intra-subject lower extremity variability changes following drop-landing height manipulations using standard deviation (SD) and coefficient of variation (CV) among lower extremity peak sagittal joint angles and moments. Fourteen healthy participants completed five drop-landing trials from five heights 20%, 60%, 100%, 140% and 180% maximum vertical jump height (MVJH). Peak joint angles and moments increased with greater landing height (p < 0.001), highlighting inter-joint differences (Flexion: Knee > Hip > Ankle, p < 0.001; Extensor Moment: Hip > Knee > Ankle, in excess of 60% MVJH, p < 0.05). Kinematic and kinetic SD increased with variable magnitudes, while CV decreased at greater landing heights (p ≤ 0.016). Decreased relative variability under greater task demands may underscore non-contact injury mechanisms from repetitive loading of identical structures.

Normative rearfoot motion during barefoot and shod walking using biplane fluoroscopy

PURPOSE

The ankle rearfoot complex consists of the ankle and subtalar joints. This is an observational study on two test conditions of the rearfoot complex. Using high-speed biplane fluoroscopy, we present a method to measure rearfoot kinematics during normal gait and compare rearfoot kinematics between barefoot and shod gait.

METHODS

Six male subjects completed a walking trial while biplane fluoroscopy images were acquired during stance phase. Bone models of the calcaneus and tibia were reconstructed from computed tomography images and aligned with the biplane fluoroscopy images. An optimization algorithm was used to determine the three-dimensional position of the bones and calculate rearfoot kinematics.

RESULTS

Peak plantarflexion was higher (barefoot: 9.1°; 95% CI 5.2:13.0; shod: 5.7°; 95% CI 3.6:7.8; p = 0.015) and neutral plantar/dorsiflexion occurred later in the stance phase (barefoot: 31.1%; 95% CI 23.6:38.6; shod: 17.7%; 95% CI 14.4:21.0; p = 0.019) during barefoot walking compared to shod walking. An eversion peak of 8.7° (95% CI 1.9:15.5) occurred at 27.8% (95% CI 18.4:37.2) of stance during barefoot walking, while during shod walking a brief inversion to 1.2° (95% CI -2.1:4.5; p = 0.021) occurred earlier (11.5% of stance; 95% CI 0.2:22.8; p = 0.008) during stance phase. The tibia was internally rotated relative to the calcaneus throughout stance phase in both conditions (barefoot: 5.1° (95% CI -1.4:11.6); shod: 3.6° (95% CI -0.4:7.6); ns.).

CONCLUSIONS

Biplane fluoroscopy can allow for detailed quantification of dynamic in vivo ankle kinematics during barefoot and shod walking conditions. This methodology could be used in the future to study hindfoot pathology after trauma, for congenital disease and after sports injuries such as instability.

LEVEL OF EVIDENCE

II.

Alterations in Glenohumeral Kinematics in Patients With Rotator Cuff Tears Measured With Biplane Fluoroscopy

PURPOSE

To quantitatively measure the 3-dimensional (3D) glenohumeral translations during dynamic shoulder abduction in the scapular plane, using a biplane fluoroscopy system, in patients with supraspinatus rotator cuff tears.

METHODS

A custom biplane fluoroscopy system was used to measure the 3D position and orientation of the scapula and humerus of 14 patients with full-thickness supraspinatus or supraspinatus and infraspinatus rotator cuff tears and 10 controls as they performed shoulder abduction over their full range of motion. The 3D geometries of the scapula and humerus were extracted from a computed tomography scan of each shoulder. For each frame, the 3D bone position and orientation were estimated using a contour-based matching algorithm, and the 3D position of the humeral head center was determined relative to the glenoid. For each subject the superior-inferior and anterior-posterior translation curves were determined from 20° through 150° of arm elevation.

RESULTS

The humeral head in shoulders with rotator cuff tears was positioned significantly inferior compared with controls for higher elevation angles of 80° to 140° (P < .05). For both groups the humeral head translated inferiorly during shoulder abduction from 80° (P = .044; rotator cuff tear v controls: -0.2 ± 1.3 v 1.2 ± 1.4 mm) up to 140° (P = .047; rotator cuff tear v controls: -1.3 ± 2.2 v 0.44 ± 1.4 mm). There was no significant translation in the anterior- posterior direction.

CONCLUSIONS

Patients with well-compensated single or 2-tendon rotator cuff tears show no dynamic superior humeral head migration but unexpectedly show an inferior shift during active elevation. It is unclear whether the size of the translational differences found in this study, while statistically significant, are also of clinical significance.

LEVEL OF EVIDENCE

Level III, comparative study.

Isokinetic Identification of Knee Joint Torques before and after Anterior Cruciate Ligament Reconstruction

The aim of this study was to evaluate the serial change of isokinetic muscle strength of the knees before and after anterior cruciate ligament reconstruction (ACLR) in physically active males and to estimate the time of return to full physical fitness. Extension and flexion torques were measured for the injured and healthy limbs at two angular velocities approximately 1.5 months before the surgery and 3, 6, and 12 months after ACLR. Significant differences (p ≤ 0.05) in peak knee extension and flexion torques, hamstring/quadriceps (H/Q) strength ratios, uninvolved/involved limb peak torque ratios, and the normalized work of these muscles between the four stages of rehabilitation were identified. Significant differences between extension peak torques for the injured and healthy limbs were also detected at all stages. The obtained results showed that 12 months of rehabilitation were insufficient for the involved knee joint to recover its strength to the level of strength of the uninvolved knee joint. The results helped to evaluate the progress of the rehabilitation and to implement necessary modifications optimizing the rehabilitation training program. The results of the study may also be used as referential data for physically active males of similar age.

A Reconfigurable High-Speed Stereo-Radiography System for Sub-Millimeter Measurement of In Vivo Joint Kinematics

Relative motions within normal and pathological joints of the human body can occur on the sub-millimeter and sub-degree scale. Dynamic radiography can be used to create a rapid sequence of images from which measurements of bone motion can be extracted, but available systems have limited speed and accuracy, limit normal subject movement, and do not easily integrate into existing traditional motion capture laboratories. A high-speed stereo radiography (HSSR) system is described that addresses these limitations. The custom radiography system was placed on a standalone reconfigurable gantry structure designed to allow freedom of subject movement while integrating into an existing motion capture laboratory. Validation of the system and measurement of knee kinematics of subjects during gait confirmed the ability to record joint motion with high accuracy and high-speed.

Deconstructing the Anterior Cruciate Ligament: What We Know and Do Not Know About Function, Material Properties, and Injury Mechanics

Anterior cruciate ligament (ACL) injury is a common and potentially catastrophic knee joint injury, afflicting a large number of males and particularly females annually. Apart from the obvious acute injury events, it also presents with significant long-term morbidities, in which osteoarthritis (OA) is a frequent and debilitative outcome. With these facts in mind, a vast amount of research has been undertaken over the past five decades geared toward characterizing the structural and mechanical behaviors of the native ACL tissue under various external load applications. While these efforts have afforded important insights, both in terms of understanding treating and rehabilitating ACL injuries; injury rates, their well-established sex-based disparity, and long-term sequelae have endured. In reviewing the expanse of literature conducted to date in this area, this paper identifies important knowledge gaps that contribute directly to this long-standing clinical dilemma. In particular, the following limitations remain. First, minimal data exist that accurately describe native ACL mechanics under the extreme loading rates synonymous with actual injury. Second, current ACL mechanical data are typically derived from isolated and oversimplified strain estimates that fail to adequately capture the true 3D mechanical response of this anatomically complex structure. Third, graft tissues commonly chosen to reconstruct the ruptured ACL are mechanically suboptimal, being overdesigned for stiffness compared to the native tissue. The net result is an increased risk of rerupture and a modified and potentially hazardous habitual joint contact profile. These major limitations appear to warrant explicit research attention moving forward in order to successfully maintain/restore optimal knee joint function and long-term life quality in a large number of otherwise healthy individuals.

Knee biomechanics during a jump-cut maneuver: effects of sex and ACL surgery

PURPOSE

The purpose of this study was to compare kinetic and knee kinematic measurements from male and female anterior cruciate ligament (ACL)-intact (ACLINT) and ACL-reconstructed (ACLREC) subjects during a jump-cut maneuver using biplanar videoradiography.

METHODS

Twenty subjects were recruited; 10 ACLINT (5 men and 5 women) and 10 ACLREC (4 men and 6 women, 5 yr postsurgery). Each subject performed a jump-cut maneuver by landing on a single leg and performing a 45° side-step cut. Ground reaction force (GRF) was measured by a force plate and expressed relative to body weight. Six-degree-of-freedom knee kinematics were determined from a biplanar videoradiography system and an optical motion capture system.

RESULTS

ACLINT female subjects landed with a larger peak vertical GRF (P < 0.001) compared with ACLINT male subjects. ACLINT subjects landed with a larger peak vertical GRF (P ≤ 0.036) compared with ACLREC subjects. Regardless of ACL reconstruction status, female subjects underwent less knee flexion angle excursion (P = 0.002) and had an increased average rate of anterior tibial translation (0.05%·ms ± 0.01%·ms, P = 0.037) after contact compared with male subjects. Furthermore, ACLREC subjects had a lower rate of anterior tibial translation compared with ACLINT subjects (0.05%·ms ± 0.01%·ms, P = 0.035). Finally, no striking differences were observed in other knee motion parameters.

CONCLUSION

Women permit a smaller amount of knee flexion angle excursion during a jump-cut maneuver, resulting in a larger peak vertical GRF and increased rate of anterior tibial translation. Notably, ACLREC subjects also perform the jump cut maneuver with lower GRF than ACLINT subjects 5 yr postsurgery. This study proposes a causal sequence whereby increased landing stiffness (larger peak vertical GRF combined with less knee flexion angle excursion) leads to an increased rate of anterior tibial translation while performing a jump-cut maneuver.

Anterior tibiofemoral intersegmental forces during landing are predicted by passive restraint measures in women

BACKGROUND

Passive restraint capabilities may influence sagittal plane knee joint mechanics during activity. This study aimed to determine if measures associated with passive restraint of anterior translation of the tibia are predictive of peak anterior knee shear force during landing.

METHODS

Passive restraint measures were assessed via joint arthrometry and during 40% body weight simulated weight acceptance using recreationally active students (73F, 42M; 21.8±2.9yr, 1.69±0.1m, 68.9±14.1kg). Anterior knee laxity (mm) at 133N and initial (0-20N) and terminal (100-130N) anterior stiffnesses (N/mm) were calculated from arthrometer data. Peak anterior tibial acceleration (m∙s(-2)) relative to the femur was assessed via electromagnetic position sensors during 40% body weight acceptance trials. Peak knee shear force was assessed during double-leg drop jumps.

RESULTS

Sex specific linear stepwise regressions revealed that in females, increasing peak tibial acceleration (5.1±1.8m·s(-2)) (R(2)∆=7.3%, P∆=0.021), increasing initial anterior stiffness (31.0±14.0N/mm) (R(2)∆=5.9%, P∆=0.032), and decreasing terminal anterior stiffness (43.4±17.4N/mm) (R(2)∆=4.9%, P∆=0.046) collectively predicted greater peak knee shear forces (66.6±12.03% BW) (multiple R(2)=18.1%). No male regressions were significant.

CONCLUSIONS

Sagittal laxity measures are associated with anterior knee shear loads during landing in females. Greater tibial acceleration during early axial load along with greater initial and lesser terminal anterior stiffnesses predicted increasing anterior knee shear forces. Future work should investigate the combined contribution of passive and active restraints to high-risk ACL biomechanics.

Variation of Anatomical and Physiological Parameters that Affect Estimates of ACL Loading During Drop Landing

BACKGROUND

Anterior cruciate ligament (ACL) loading during drop landing has been recently studied with a sagittal plane knee model developed by Kernozek and Ragan using mean anatomical and physiological parameters obtained from cadaveric and clinical data. It is unknown how estimates in ACL load may be altered due to variations in anatomical and physiological parameters used from other research.

METHODS

USING THE SAME MODEL, THESE PARAMETERS WERE SYSTEMATICALLY VARIED, INCLUDING: tibial slope, moment arms of the patellar tendon, hamstring, and gastrocnemius at the knee and ankle, patellar tendon and hamstring line of force, ACL stiffness, and nonlinear muscle activation parameters. To determine the sensitivity of the model to changes in these parameters, each was varied independently by ±5% and by ranges reported in the literature. Changes in maximum ACL load and shear force components of the patellar tendon, hamstring, and tibio-femoral contact force were calculated from drop landing data of 21 subjects.

RESULTS

The variation in ACL load during drop landing from its nominal value was largest (-100% to 176%) when extremes in reported tibial slope values were utilized. Variation in the next most important parameter, patellar tendon line of force, affected ACL load by -72% to 88%.

CONCLUSION

Variations in tibial slope and patellar tendon line of force had the greatest influence on estimated ACL loading during drop landing. Differences in these parameters between subjects may be just as important to ACL loading as the kinematic and kinetic performance differences observed in landing.

Integrated assessment techniques for linking kinematics, kinetics and muscle activation to early migration: a pilot study

The goal of this pilot study was to develop and test an integrated method to assess kinematics, kinetics and muscle activation of total knee prostheses during dynamic activities, by integrating fluoroscopic measurements with force plate, electromyography and external motion registration measurements. Subsequently, this multi-instrumental analysis was then used to assess the relationship between kinematics, kinetics and muscle activation and early migration of the tibial component of total knee prostheses. This pilot study showed that it is feasible to integrate fluoroscopic, kinematic and kinetic measurements and relate findings to early migration data. Results showed that there might be an association between deviant kinematics and early migration in patients with a highly congruent mobile-bearing total knee prosthesis. Patients that showed high levels of coactivation, diverging axial rotations of the insert and a deviant pivot point showed increased migration and might be at higher risk for tibial component loosening. In the future, to confirm our findings, the same integrated measurements have to be performed in larger patient groups and different prosthesis designs.

Sex-dimorphic landing mechanics and their role within the noncontact ACL injury mechanism: evidence, limitations and directions

Anterior cruciate ligament (ACL) injuries continue to present in epidemic-like proportions, carrying significant short- and longer-term debilitative effects. With females suffering these injuries at a higher rate than males, an abundance of research focuses on delineating the sex-specific nature of the underlying injury mechanism. Examinations of sex-dimorphic lower-limb landing mechanics are common since such factors are readily screenable and modifiable. The purpose of this paper was to critically review the published literature that currently exists in this area to gain greater insight into the aetiology of ACL injuries in females and males. Using strict search criteria, 31 articles investigating sex-based differences in explicit knee and/or hip landing biomechanical variables exhibited during vertical landings were selected and subsequently examined. Study outcomes did not support the generally accepted view that significant sex-based differences exist in lower-limb landing mechanics. In fact, a lack of agreement was evident in the literature for the majority of variables examined, with no sex differences evident when consensus was reached. The one exception was that women were typically found to land with greater peak knee abduction angles than males. Considering knee abduction increases ACL loading and prospectively predicts female ACL injury risk, its contribution to sex-specific injury mechanisms and resultant injury rates seems plausible. As for the lack of consensus observed for most variables, it may arise from study-based variations in test populations and landing tasks, in conjunction with the limited ability to accurately measure lower-limb mechanics via standard motion capture methods. Regardless, laboratory-based comparisons of male and female landing mechanics do not appear sufficient to elucidate causes of injury and their potential sex-specificity. Sex-specific in vivo joint mechanical data, if collected accurately, may be more beneficial when used to drive models (e.g., cadaveric and computational) that can additionally quantify the resultant ACL load response. Without these steps, sex-dimorphic landing mechanics data will play a limited role in identifying the aetiology of ACL injuries in women and men.