Bilateral Medial Tibiofemoral Joint Stiffness in Full Extension and 20° of Knee Flexion (original) (raw)
Related papers
Tibiofemoral Joint Positioning for the Valgus Stress Test
Journal of Athletic Training, 2010
Context: Recommendations on the positioning of the tibiofemoral joint during a valgus stress test to optimize isolation of the medial collateral ligament (MCL) from other medial joint structures vary in the literature. If a specific amount of flexion could be identified as optimally isolating the MCL, teaching and using the technique would be more consistent in clinical application.
The Effects of Tibiofemoral Angle and Body Weight on the Stress Field in the Knee Joint
Volume 2: Biomedical and Biotechnology Engineering, 2007
Osteoarthritis (OA) is a degenerative disease of articular cartilage that may lead to pain, limited mobility and joint deformation. It has been reported that abnormal stresses and irregular stress distribution may lead to the initiation and progression of OA. Body weight and the frontal plane tibiofemoral angle are two biomechanical factors which could lead to abnormal stresses and irregular stress distribution at the knee. The tibiofemoral angle is defined as the angle made by the intersection of the mechanical axis of the tibia with the mechanical axis of the femur in the frontal plane. In this study, reflective markers were placed on the subjects' lower extremity bony landmarks and tracked using motion analysis. Motion analysis data and force platform data were collected together during single-leg stance, double-leg stance and walking gait from three healthy subjects with no history of osteoarthritis (OA), one with normal tibiofemoral angle (7.67º), one with varus (bow-legged) angle (0.20º) and one with valgus (knocked-knee) angle (10.34º). The resultant moment and forces in the knee were derived from the data of the motion analysis and force platform experiments using inverse dynamics. The results showed that Subject 1 (0.20º valgus) had a varus moment of 0.38 N-m/kg, during single-leg stance, a varus moment of 0.036 N-m/kg during static double-leg stance and a maximum varus moment of 0.49 N-m/kg during the stance phase of the gait cycle. Subject 2 (7.67º valgus tibiofemoral angle) had a varus moment of 0.31 N-m/kg, during single-leg stance, a valgus moment of 0.046 N-m/kg during static double-leg stance and a maximum varus moment of 0.37 N-m/kg during the stance phase of the gait cycle. Subject 3 (10.34º valgus tibiofemoral angle) had a varus moment of 0.30 N-m/kg, during single-leg stance, a valgus moment of 0.040 N-m/kg during static double-leg stance and a maximum varus moment of 0.34 N-m/kg during the stance phase of the gait cycle. In general, the results show that the varus moment at the knee joint increased with varus knee alignment in static single-leg stance and gait.
Collateral ligament strains during knee joint laxity evaluation before and after TKA
Clinical Biomechanics, 2013
Background: Passive knee stability is provided by the soft tissue envelope. There is consensus among orthopedic surgeons that good outcome in Total Knee Arthroplasty requires equal tension in the medial/lateral compartment of the knee joint, as well as equal tension in the flexion/extension gap. The purpose of this study was to quantify the ligament laxity in the normal non-arthritic knee before and after Posterior-Stabilized Total Knee Arthroplasty. We hypothesized that the Medial/Lateral Collateral Ligament shows minimal changes in length when measured directly by extensometers in the native human knee during varus/valgus laxity testing. We also hypothesized that due to differences in material properties and surface geometry, native laxity is difficult to reconstruct using a Posterior-Stabilized Total Knee. Methods: Six specimens were used to perform this in vitro cadaver test using extensometers to provide numerical values for laxity and varus-valgus tilting in the frontal plane. Findings: This study enabled a precise measurement of varus-valgus laxity as compared with the clinical assessment. The strains in both ligaments in the replaced knee were different from those in the native knee. Both ligaments were stretched in extension, in flexion the Medial Collateral Ligament tends to relax and the Lateral Collateral Ligament remains tight. Interpretation: As material properties and surface geometry of the replaced knee add stiffness to the joint, we recommend to avoid overstuffing the joint, when using this type of Posterior-Stabilized Total Knee Arthroplasty, in order to obtain varus/valgus laxity close to the native joint.
The relationships between active extensibility, and passive and active stiffness of the knee flexors
Journal of Electromyography and Kinesiology, 2004
Insufficient active knee flexor stiffness may predispose the anterior cruciate ligament to injury. Insufficient passive stiffness may result in insufficient active stiffness. Similarly, higher levels of musculotendinous extensibility may inhibit active and passive muscle stiffness, potentially contributing to an increased risk of injury. The literature is both limited and inconsistent concerning relationships between extensibility, passive stiffness, and active stiffness. Extensibility was measured as the maximal active knee extension angle from a supine position with the hip flexed to 90 v . Passive stiffness was calculated as the slope of the momentangle curve resulting from passive knee extension. Active stiffness was assessed via acceleration associated with damped oscillatory motion about the knee. Stepwise multiple regression indicated that passive stiffness accounted for 25% of active muscle stiffness variance. The linear combination of extensibility and passive stiffness explained only 2% more variance compared to passive stiffness alone. Musculotendinous extensibility was moderately related to passive muscle stiffness, and weakly related to active muscle stiffness. The moderate relationship observed between active and passive stiffness emphasizes the dependence of active muscle stiffness on cross-bridge formation, and the relatively smaller contribution from parallel elastic tissues. Additionally, heightened extensibility does not appear to be a predisposing factor for reduced muscle stiffness. #
Journal of Orthopaedic Research, 2005
Past studies of the healing of the medial collateral ligament (MCL) in animal models have been conducted over a variety of healing intervals, some as early as 1 week. One concern with testing at early healing intervals is the difficulty in identifying and isolating the tissues that carry load. The purpose of this study was to determine if isolation of the MCL and healing time are critical factors in the assessment of structural strength in this model. Furthermore, the effect of immobilization on these critical factors was investigated. Our approach was to calculate the load-sharing ratio between the MCL and the MCL plus capsule. A 4 mm gap was created in the midsubstance of both hindlimb MCLs of 52 female New Zealand White rabbits (n = 104). Of these, 29 rabbits had their right hindlimb pin immobilized (immobilized group), leaving the left hindlimb non-immobilized. Testing was performed at 3 (n = 12), 6 (n = 22), and 14 (n = 24) weeks. The remaining 23 rabbits, which had both limbs non-immobilized (non-immobilized group), were tested at 3 (n = lo), 6 (n = 12), 14 (n = 12), and 40 (n = 12) weeks. For both groups, half of the specimens at each healing interval were used to test the MCL alone and half to test the MCL plus capsule, except for 3 week immobilized joints where only the MCL plus capsule was tested. Additionally, MCL (n = 12), MCL plus capsule (n = 6), and capsule alone (n = 5) were tested from normal animals. The load-sharing ratio at MCL failure for the normal joint was 89%, suggesting an MCL-dominated response. For the nonimmobilized group, the load-sharing ratio was 24% at 3 weeks of healing, suggesting a capsule-dominated response. At and after 6 weeks of healing, an MCL-dominated response was observed, with the ratio being 68% or greater. Thus, at less than 6 weeks of healing, the structural strength capabilities of the joint may be better represented by the medial structures rather than the isolated MCL. Immobilization delayed the transition from a capsule-dominated response to an MCL-dominated response in this model.
Journal of ISAKOS: Joint Disorders & Orthopaedic Sports Medicine
ObjectiveInvestigate the patellar force-displacement profile (ligament stiffness) of patellofemoral disorders.MethodsFifty-two knees from 34 consecutive patients (mean 31.6 years and 53% male) were analysed including 24 knees with patellofemoral pain (PFP), 19 with potential patellofemoral instability (PPI) and 9 with objective patellofemoral instability (OPI). Physical examination, patient-reported outcome measures (Kujala and Lysholm Scores), standard radiography and MRI or CT were performed in all patients. Instrumented stress testing (Porto Patella testing device) concomitantly with imaging (MRI or CT) was performed to calculate ligament stiffness.ResultsThe force-displacement curves in patients with PPI and OPI displayed a similar pattern, which was different from that of the PFP group. Patients with PPI showed higher ligament stiffness (a higher force was required to displace the patella) than the patients in the OPI group. Patients with OPI had a statistically significant sha...
Mechanics of the knee. A study of joint and muscle load with clinical applications
PubMed, 1985
The load moment of force about the knee joint during machine milking and when lifting a 12.8 kg box was quantified using a computerized static sagittal plane body model. Surface electromyography of quadriceps and hamstrings muscles was normalized and expressed as a percentage of an isometric maximum voluntary test contraction. Working with straight knees and the trunk flexed forwards induced extending knee load moments of maximum 55 Nm. Lifting the box with flexed knees gave flexing moments of 50 Nm at the beginning of the lift, irrespective of whether the burden was between or in front of the feet. During machine milking, a level difference between operator and cow of 0.70 m - 1.0 m significantly lowered the knee extending moments. To quantify the force magnitudes acting in the tibio-femoral and patello-femoral joints, a local biomechanical model of the knee was developed using a combination of cadaver knee dissections and lateral knee radiographs of healthy subjects. The moment arm of the knee extensor was significantly shorter for women than for men, which resulted in higher knee joint forces in women if the same moment was produced. A diagram for quantifying patellar forces was worked out. The force magnitudes given by the knee joint biomechanical model correlated well with experimentally forces measured by others. During the parallel squat in powerlifting, the maximum flexing knee load moment was estimated to 335-550 Nm when carrying a 382.5 kg burden and the in vivo force of a complete quadriceps tendon-muscle rupture to between 10,900 and 18,300 N. During isokinetic knee extension, the tibio-femoral compressive force reached peak magnitudes of 9 times body weight and the anteroposterior shear force was close to 1 body weight at knee angles straighter than 60 degrees, indicating that high forces stress the anterior cruciate ligament. A proximal resistance pad position decreased the shear force considerably, and this position is recommended in early rehabilitation after anterior cruciate ligament repairs or reconstructions. The methods presented quantify muscle activity, sagittal knee joint moments and forces, enabling assessments to be made of different work postures, training exercises and joint derangements.
Archives of Physical Medicine and Rehabilitation, 2003
Objectives: To present the original descriptions of common orthopedic physical examination maneuvers of the knee and then to review the literature to support the scientific validity of these tests. Data Sources: MEDLINE (1970-2000) searches were performed, as were reviews of various musculoskeletal examination textbooks that describe physical examination maneuvers of the knee. These references were then reviewed for additional references and crossed back to the original description (when possible) of these named tests. Study Selection: All articles that discussed the sensitivity and specificity of the physical examination maneuvers were extracted. This information was reviewed for accuracy and then summarized. Data Extraction: Multiple MEDLINE and text searches were performed by using the terms of the test maneuver, the joint tested, and the term physical examination. Any article with this information was reviewed until the article describing the original description was found. Articles dating from that original article to the present were reviewed for information on the sensitivity and specificity of the test. Data Synthesis: Literature reviewing the sensitivity and specificity of the tests reviewed is summarized in text and table form. The Lachman test seems to be very sensitive and specific for the detection of anterior cruciate ligament tears. For posterior cruciate ligament tears, the posterior drawer test is also very sensitive and specific and is enhanced with other tests, such as the posterior sag sign. For meniscal tears, the McMurray test is very specific but has a very low sensitivity, whereas joint line tenderness has fairly good sensitivity but lacks good specificity. Although collateral ligament testing seems to be sensitive and specific, there is a lack of well-designed studies that scientifically validate the sensitivity and specificity of these tests. Common tests for patellofemoral pain and patellar instability lack sensitivity when correlated with pathologic operative findings. Conclusions: Most physical examination tests could be referenced back to an original description, with variable information on the sensitivity and specificity along with other information about the validity of these tests in clinical practice. To standardize how physical examinations are performed and compared, they should follow the original description or agreed-on standards. In addition, the significance of a physical examination finding must be understood to ensure that patients with knee complaints are accurately diagnosed and properly treated.
BMC Musculoskeletal Disorders
Background: We compared the functional outcome between conventional and high-flexion total knee arthroplasty (TKA) using kneeling and sit-to-stand tests at 1 year post-operative. In addition, the patient's daily functioning, pain and satisfaction were quantified using questionnaires. Methods: We randomly assigned 56 patients to receive either a conventional or a high-flexion TKA. Primary outcomes were maximum flexion angle and maximum thigh-calf contact measured during kneeling at 1 year post operatively. Secondary outcomes were the angular knee velocity and ground reaction force ratio measured during sit-to-stand performance tests, and questionnaires. Results: At one year post-operative, maximum knee flexion during kneeling was higher for the high-flexion TKA group (median 128.02°(range 108-146)) compared to the conventional TKA group (119.13°(range 72-135)) (p = 0.03). Maximum thigh-calf contact force was higher for the high flexion TKA group (median 17.82 N (range 2.98-114.64)) compared to the conventional TKA group (median 9.37 N (range 0.33-46.58))(p = 0.04). The sit-to-stand tests showed a significantly higher angular knee velocity in the conventional TKA group (12.12 rad/s (95%CI 0.34-23.91); p = 0.04). There were no significant differences between groups in ground reaction force ratios and patient-reported outcome scores. Conclusion: Although no differences were found in patient-reported outcome scores, differences in performance-based tests were clearly apparent. Standing up from a chair at 90°of knee flexion appeared to be easier for the conventional group. The kneeling test revealed significantly higher weight-bearing knee flexion for the high-flex group. Hence, if kneeling is an important activity for a patient a high-flex design may be recommendable. Trial registration: The study was retrospectively registered in ClinicalTrials.gov under identifier NCT00899041 (date of registration: May 11, 2009).