Femorotibial rotation is linearly associated with tibial tubercle-trochlear groove distance: A cadaveric study.

OBJECTIVES: A tibial tubercle-trochlear groove (TT-TG) distance of 20 millimeters (mm) is typically used when determining whether tibial tubercle medialization is performed for the surgical treatment of patellar instability. Without knowledge of how the variability of an individual's TT-TG distance is influenced by through-the-knee femorotibial rotation, the use of a specific TT-TG distance during preoperative planning for patellar instability may lead to incorrect decisions on the use of tibial tubercle medialization. We hypothesized that knee joint internal/external (IE) rotation is related to the TT-TG distance. METHODS: Eight independent human cadaveric knee specimens (age: 32 â€‹± â€‹6 years; 4 males, 4 females) were utilized. A robotic manipulator (ZX165U, Kawasaki Robotics, Wixom, MI, USA) instrumented with a universal force/moment sensor was used to determine knee joint IE rotation under applied moments of ±5 newton-meters (Nm) at full extension. Two independent reviewers selected the trochlear groove and tibial tuberosity points on computerized tomography (CT) images of each specimen to define TT-TG. To determine the influence of knee joint IE rotation on TT-TG distance, three-dimensional (3D) models generated from CT scans were registered to tibiofemoral kinematics. Linear regression was performed to determine the relationship between knee joint IE rotation and TT-TG distance. The regression coefficient, standard error of measurement (α â€‹= â€‹0.05), and coefficient of determination (r2) were reported. RESULTS: At 0° of rotation, the mean TT-TG distance was 14.2 â€‹± â€‹5.0 â€‹mm. Knee joint IE rotation averaged 23.0 â€‹± â€‹4.2°. For every degree of knee joint IE rotation, TT-TG distance changed by 0.52 â€‹mm. CONCLUSION: TT-TG distance was linearly dependent on knee joint IE rotation, changing by 0.52 â€‹mm for every degree of knee joint IE rotation. Thus, an offset of IE rotation of 10° would lead to a change in TT-TG distance of 5.2 â€‹mm, enough to alter the surgical decision-making for/or against tibial tubercle medialization. LEVEL OF EVIDENCE: IV: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Analysis of passive tibio-femoral joint movement of Beagle dogs during flexion in cadaveric hind limbs without muscle.

The aim of this study was to evaluate the normal range of motion of the canine tibiofemoral joint and the movement of the tibia relative to the femur, especially the internal/external rotation under flexion. Right stifle joints were harvested from eight skeletally mature Beagle dogs, which were euthanized for reasons unrelated to this study. All muscle tissue was removed from the limbs prior to testing. Flexion and extension tests were conducted using a robotic manipulator with six degrees-of-freedom. Cranial/caudal and medial/lateral displacement and varus/valgus and internal/external rotation were measured at various degrees of flexion. We observed that the tibia rotated internally at an increasing flexion angle with mean peak internal and external rotations of 20.0 ± 13.8° and 4.5 ± 3.6°, respectively. The tibia also tended to displace cranially at an increasing flexion angle, with a mean peak cranial displacement of 8.9 ± 4.4 mm; there was minimal medial displacement when increasing the flexion angle. Valgus rotation also tended to occur at an increasing flexion angle. During the flexion of the canine stifle joint, approximately 20° of internal tibial rotation occurred around the longitudinal axis, along with a rollback motion involving the cranial displacement of the tibia.

Correcting lower limb segment axis misalignment in gait analysis: A simple geometrical method.

BACKGROUND: Obtaining precise and repeatable measurements is essential to clinical gait analysis. However, defining the thigh medial-lateral axis segment remains a challenge, with particular implications for the hip rotation profile. Thigh medial-lateral axis misalignment modifies the hip rotation profile and can result in a phenomenon called crosstalk, which increases knee adduction-abduction amplitude artificially. RESEARCH QUESTION: This study proposes an a posteriori geometrical method based solely on segment anatomy that aims to correct the thigh medial-lateral axis definition and crosstalk-related error. METHODS: The proposed method considers the thigh medial-lateral axis as the normal to the mean sagittal plane of the lower limb defined by hip, knee and ankle joint centres during one gait cycle. Its performance was compared to that of an optimisation method which repositions the axis to reduce knee abduction-adduction variance. An existing dataset was used: 75 patients with a knee prosthesis undergoing gait analysis three months and one-year post-surgery. Three-dimensional hip and knee angles were computed for two gait analysis sessions. Crosstalk was quantified using both the coefficient of determination (r²) between knee flexion-extension and adduction-abduction and the amplitude of knee adduction-abduction. The reproducibility of hip internal-external rotation was also quantified using the inter-trial, inter-session and inter-subject standard deviations and the intraclass coefficient (ICC). RESULTS: Crosstalk was significantly reduced from r² = 0.67 to r² = 0.51 by the geometrical method but remained significantly higher than with the optimisation method with a r² < 0.01. SIGNIFICANCES: Both methods allowed to improve the hip internal-external reproducibility from poor to moderate (original data: ICC = 0.34, geometrical method: ICC = 0.65, optimisation method ICC = 0.73). One advantage of the geometrical method is that, unlike the optimisation method, it does not require much movement, making it suitable for a wider range of patients.

Intraoperative kinematic analysis of posterior stabilized total knee arthroplasty with asymmetric helical post-cam design.

PURPOSE: To investigate intraoperative kinematics during passive flexion using a surgical navigation system for knees undergoing posterior stabilized (PS) total knee arthroplasty (TKA) with an asymmetric helical post-cam design using navigation system. METHODS: In total, 45 knees with both pre- and postoperative kinematic data available were included in the study. Intraoperative kinematic measurements were performed during the course of surgery using the software incorporated in the navigation system. Measurements were performed at the following two time points: (1) before TKA procedure and (2) after TKA implantation. Among the kinematic parameters studied, anterior/posterior translation and axial rotation during flexion were subjected to the analysis. RESULTS: Before surgery, physiologic anterior/posterior translational pattern of the tibia during flexion (rollback of the femur) was found in only 15.6% of the knees. After TKA implantation, postoperative kinematic measurement showed no significant change in the tibial translational during knee flexion. Similarly, with regard to rotation, non-physiologic external tibial rotation in early flexion was observed in the majority of the knees before surgery, and this abnormal kinematic pattern remained after the TKA procedure. CONCLUSIONS: The intraoperative three-dimensional motion analysis using a navigation system showed that the physiologic kinematic pattern (anterior translation and internal rotation of the tibia during flexion) of the knee was distorted in osteoarthritic knees undergoing TKA. The abnormal kinematic pattern before surgery was not fully corrected even after implantation of the PS TKA designed to induce natural knee motion; however, no clear relationship between the intraoperative kinematic pattern and knee flexion angle at one year was demonstrated, and the effect of knee kinematics on postoperative knee function and patient's satisfaction is still unclear.

Examining the influence of grip type on wrist and club head kinematics during the golf swing: Benefits of a local co-ordinate system.

Wrist movements have been identified as an important factor in producing a successful golf swing, with their complex motion influencing both club head velocity and orientation. However, a detailed analysis of wrist angles is lacking in the literature. The purpose of this study was to determine kinematics across wrists and club head characteristics during the golf swing under weak, neutral and strong grip conditions. Twelve professional male golfers executed 24 shots using a driver under three grip conditions. A six degrees of freedom analysis of the hand with respect to the distal forearm was performed using a 10-camera three-dimensional motion capture system. Differences in joint angles were explored using repeated measures ANOVAs at key swing events (onset, top of backswing and impact), in addition club head velocity and clubface angle at impact were also explored. Main findings revealed significant differences in flexion/extension and internal/external rotation for both wrists at all swing events, whereas fewer significant interactions were found in ulnar/radial deviation across grips for both wrists at all events. Clubface angle only differed significantly between the weak and the strong and neural grips, presenting a more 'open' clubface to the intended hitting direction. This study is the first to explore tri-planar wrist movement and the effect of different grips, such analysis has implications for coaching knowledge and practice and should inform future research into different aspects of skill, technique analysis and may inform injury mechanisms/prevention.

Comparison of the kinematics and kinetics of shoulder exercises performed with constant and elastic resistance.

BACKGROUND: Internal and external rotation exercises of the shoulder are frequently performed to avoid injury and pain. Knowledge about the motion and loadings of the upper extremities during these exercises is crucial for the development of optimal training recommendations. However, a comparison of the angles and corresponding moments in the upper extremities that are achieved during internal and external rotation exercises for the shoulder by using different resistance types has not yet been performed. Therefore, the aim of the study was to examine upper extremity kinetics and kinematics in 3D of the internal and external rotation exercises. METHODS: The kinematics and kinetics of 12 participants while they performed 10 different exercises with a constant and with an elastic external load corresponding to 2% body mass was assessed. The motion of the upper extremities was recorded three-dimensionally with a motion capture system, using a newly developed marker set and joint coordinate systems with 28 markers. The applied external load was measured with a load cell placed in series with the external resistance, and moments were calculated using an inverse dynamics approach. RESULTS: The range of motion and the joint loading was highly dependent on the exercises. The range of motion in the glenohumeral joint did not differ significantly between the two resistance types, whereas internal/external rotation moments were significantly higher with constant resistance than those with elastic resistance. CONCLUSIONS: Larger or lower moments can, therefore, be achieved through selection of the appropriate resistance type, while the range of motion can be altered through the selection of exercise type. Therefore, the loading motion patterns identified in this study can help to choose suitable shoulder exercises dependent on the training objective.

Location of the natural knee axis for internal-external tibial rotation.

BACKGROUND: Rotating hinge and mobile bearing tray knee replacement designs utilize a single fixed axis for tibial rotation, yet there is little published information regarding the natural internal-external axis (IEA) for tibial rotation. Identifying the IEA should provide an opportunity for reproducing normal knee kinematics and maintaining the balance of forces in the soft tissues that help control rotation of the tibia. METHODS: The location and orientation of the IEA relative to the tibial plateau were calculated in 46 fresh frozen human cadaveric specimens using an instant center of rotation analysis at fixed knee flexion angles ranging from five degrees to 105°. RESULTS: IEA location ranged from 4.0 to 4.9mm medial and 1.7 to 5.5mm posterior to the center of the tibial plateau (from 5° to 105° of knee flexion). IEA orientation was reported relative to a reference axis perpendicular to the plane of the tibial plateau. In the frontal plane, the IEA was not significantly different from the reference axis from five degrees to 45° flexion, and 2.0° to 2.7° valgus to the reference axis from 60° to 105° flexion. In the sagittal plane, the IEA was not significantly different from the reference axis from 5° to 15° flexion, and 3.0° to 7.0° extended from the reference axis from 30° to 105° flexion. CONCLUSIONS: The IEA moves posteriorly with increasing knee flexion on the tibial plateau. Placement of the IEA relative to the tibial plateau for a rotating hinge or mobile bearing tray implant may represent a compromise between design objectives for moderate and deeper knee flexion. CLINICAL RELEVANCE: This study has relevance for future knee implant designs.

The biomechanical effect of bilateral unloading knee brace with internal-external rotation on knee joint / 医用生物力学

Objective Aiming at reducing the restrictions on lower limbs imposed by traditional knee brace, a design scheme for knee brace complying with internal-external rotation is proposed. Methods By adding the internal-external hinge, the knee brace could help to release the degree of freedom (DOM) of internal-external rotation of the knee. In the experimental group, the subject was required to wear the bilateral unloading knee brace with or without internal-external hinges, respectively, while in the control group, the subject did not wear the knee brace. Then gait experiment and mechanical testing were conducted. Results In gait experiment, the bilateral unloading knee brace with internal-external hinges imposed less restriction on the knee than that from the knee brace without internal-external hinges, and it could also provide some distractive force for the knee joint. Conclusions The internal-external hinge design can help to reduce restrictions on the knee imposed from bilateral unloading knee brace.

Reliability of freehand three-dimensional ultrasound to measure scapular rotations.

The objective of this study was to evaluate the reliability of using freehand three-dimensional ultrasound to measure scapular rotations (internal/external, upward/downward, anterior/posterior). The scapular position in 22 healthy, nondisabled individuals was imaged three times in four testing positions of interest (arm at rest and humeral elevation in the sagittal, frontal, and scapular planes). We found substantial reliability across scanning positions and scapular rotations, with intraclass correlation coefficients ranging from 0.62 to 0.95. The highest reliability was found in the rest testing position. Our standard error of measurement was less than 2 degrees for all measurements and less than 0.5 degrees for most. Minimum detectable change ranged from 0.37 to 3.08 degrees. Our results agree with the pattern of movement found in other studies, with the scapula moving toward a more externally rotated, upwardly rotated, and posteriorly tilted position with humeral elevation. Further study is warranted to compare our methods to a gold standard, apply them to evaluating dynamic movement, and determine whether they can be used to detect shoulder pathology.

Biotribology of a mobile bearing posterior stabilised knee design--effect of motion restraint on wear, tibio-femoral kinematics and particles.

The objective of our study was to evaluate the impact of a biphaseal anterior-posterior (AP) and internal-external (IE) motion restraint system on the wear behaviour, tibio-femoral kinematics and particle release of a mobile bearing posterior stabilised knee design in comparison to the widely used linear restraint. in vitro wear simulation was performed using a posterior stabilised total knee replacement with a mobile rotating platform gliding surface design to compare the standard ISO 14243-1:2002 (E) protocol with a linear AP and IE motion restraint and the new ISO 14243-1:2009 (E) protocol with a biphaseal AP and IE motion restraint. For the mobile gliding surfaces, an increase in wear rate by more than a magnitude was measured applying the biphaseal protocol (8.5±1.6 mg/million cycles) in a direct comparison to the linear protocol (0.33±0.07 mg/million cycles), with statistically significant difference. The amplitudes of AP displacement were 3.22±0.47 mm for the biphaseal test, compared to 1.97±0.22 mm in the linear test and the amplitudes of the IE rotation angle had mean values of 7.32°±0.91° under the biphaseal setup, compared to 1.97°±0.14° under linear motion restraint test conditions. From our observations, we conclude that the changes in AP translation and IE rotation motion restraints from ISO linear to ISO biphaseal test conditions highly impact the knee joint kinematics and wear behaviour of a mobile bearing posterior stabilised knee design.