Freedom in Osteoarthritis of the Knee

The first peak of the external knee abduction moment (KAM) is often used as a surrogate measure of the medial compartment loading and has been correlated with pain and progression of knee osteoarthritis (OA). As a result, reducing the KAM is often the target of conservative interventions. OA should be considered as a “Whole Person” disease, including ecological psychosocial aspects. Scientists have developed gait alteration strategies to reduce the KAM. They attempted to force into a new position any particular part without reference to the pattern of the whole. We propose an alternative approach: in the vicinity of a special configuration of the knee, some or all of the components of the knee become overloaded. This study has shown that when six lines $1′,$2′,$3′,$4′,$5′,$6′ are so situated that forces acting along them equilibrate when applied to one degree of freedom, 1° F knee, a certain determinant vanishes. We wish to define the six lines as the knee complex in involution by virtue of some constraint upon the knee.

Biomechanical Features of Drop Vertical Jump Are Different Among Various Sporting Activities

Background: Risk for non-contact anterior cruciate ligament (ACL) injury can be assessed based on drop vertical jump (DVJ). However, biomechanics of DVJ should differ with type of various sporting activities. The purpose of the present study was to clarify whether biomechanical features of DVJ are different among various sporting activities in female athletes.Methods: A total of 42 female athletes, including 25 basketball, 8 soccer and 9 volleyball players, participated in the current investigation. DVJ was done for each female athlete using a three-dimensional motion analysis system which consisted of six cameras, two force plates and 46 retro-reflective markers. Kinematic and kinetic data were recorded for both limbs in each athlete. Simultaneously, frontal and sagittal plane views of the DVJ were recorded using high-resolution two different video cameras to evaluate Landing Error Scoring System (LESS) score. Three-dimensional biomechanical parameters at the knee joint and LESS were compared among three different sporting activities.Results: Soccer players had better LESS score, compared to basketball players, while no significantly differences were found between basketball and volleyball players in LESS. In addition, peak knee flexion angle was significantly larger, and knee abduction angle at initial contact (IC), peak knee abduction angle, knee internal rotation angle, and knee abduction moment within 40 milliseconds from IC were significantly smaller in soccer players, compared to basketball players. There were no significantly differences between basketball and volleyball players in all biomechanical parameters.Conclusions: From the present study, female basketball and volleyball players have worse LESS score, greater knee abduction angle and moment, compared to female soccer players. Thus, female basketball and volleyball players are likely to have the increased risk of non-contact ACL injury during DVJ, compared to soccer players. DVJ may be useless as a screening tool of non-contact ACL injury for soccer players. Biomechanics of DVJ depends on characteristics of the athlete's primary sport.

Running Readiness Scale as an assessment of kinematics related to knee injury in female novice runners

CONTEXT Frontal and transverse plane kinematics were prospectively identified as risk factors for running-related injuries in females. The Running Readiness Scale (RRS) may allow for clinical evaluation of these kinematics. OBJECTIVES To assess reliability and validity of the RRS as an assessment of frontal and transverse plane running kinematics. DESIGN Cross-sectional SETTING University research laboratory. PATIENTS OR OTHER PARTICIPANTS 56 female novice runners. MAIN OUTCOME MEASURES 3D kinematics were collected during running and RRS tasks: hopping, plank, step-ups, single-leg squats, and wall-sit. RRS performances were assessed by 5 assessors, 3 times each. Inter- and intra-rater reliabilities of total RRS score and individual tasks were calculated using intraclass correlation coefficient and Fleiss kappa, respectively. Pearson correlation coefficients between peak joint angles measured during running and the same angles measured during RRS tasks were calculated. Peak joint angles of high vs. low scoring participants were compared. RESULTS Inter- and intra-rater reliabilities of assessment of the total RRS scores were good. Reliability of the assessment of individual tasks were moderate to almost perfect. Peak hip adduction, pelvic drop, and knee abduction during running were correlated with the same angles measured during hopping, step-ups, and single-leg squats (r=0.537–0.939). Peak knee internal rotation during running was correlated with peak knee internal rotation during step-ups (r=0.831). Runners who scored high on the RRS demonstrated less knee abduction during running. CONCLUSIONS The RRS may be an effective evaluation of knee abduction in novice runners, but evaluation criteria or tasks may need to be modified for effective assessment of pelvis and transverse plane knee kinematics.

Increased Trunk Kinetics Observed During Dose-Specific Trunk Lean Gait Modification

Trunk modification is associated with knee abduction moment reduction in both healthy groups and individuals with knee osteoarthritis. Ambulatory-related changes in trunk kinematics have been implicated in increased trunk moment. The purpose of this study was to investigate the effect of dose-specific lateral trunk lean on trunk kinetics during ipsilateral and contralateral stance phases. Nineteen healthy participants completed 10 baseline walking trials, followed by 10 trials employing lateral trunk lean. Trunk modification magnitudes were determined based on the average baseline trunk angle. Five trials of both small and large trunk modification magnitudes were completed. Visual real-time biofeedback was projected as a line graph displaying the trunk angle during stance, and a highlighted bandwidth was designated the target range. A 1-factor repeated-measures analysis of variance or Friedman test was used to assess differences between the conditions (P < .05) in trunk dependent measures. Trunk kinetics displayed significant increases, even during modest modifications to the trunk angle. The participants experienced increased peak frontal plane trunk moment and angular impulse during ipsilateral stance. The observed increase in the peak lateral joint reaction force is suggestive of a compromised loading environment at the spine. Implementing trunk modification might result in unintended secondary changes along the kinetic chain, but further investigation is required.

Immediate Effect of Anterior Cruciate Ligament Protective Knee Taping on Knee Landing Mechanics and Muscle Activations during Side Hops

Athletic taping is widely used in sports to prevent injury. However, the effect of anterior cruciate ligament (ACL) protective taping on neuromuscular control during dynamic tasks remains unclear. Therefore, this study aimed to investigate the immediate effect of ACL protective taping on landing mechanics and muscle activations during side hops in healthy individuals. Fifteen healthy individuals (11 males and 4 females; age, 23.1 ± 1.4 years; height, 175.1 ± 10.4 cm; weight, 66.3 ± 11.2 kg) volunteered to participate in this study. Landing mechanics and muscle activations were measured while each participant performed single-leg hops side-to-side for ten repetitions with and without taping. An optical motion capture system and two force plates were used to collect the kinematic and kinetic data during the side hops. Surface electromyogram recordings were performed using a wireless electromyography system. Paired t-tests were performed to determine the differences in landing mechanics and muscle activations between the two conditions (taping and non-taping). The level of significance was set at p < 0.05. Compared with the non-taping condition, participants landed with a smaller knee abduction angle, greater knee external rotation angle, and smaller knee extensor moment in the taping condition. Given that greater knee abduction, internal rotation, and knee extension moment are associated with a greater risk of ACL injury, our findings suggest that ACL protective taping can have an immediate effect on dynamic knee stability. Clinicians should consider using ACL protective taping to facilitate the use of favorable landing mechanics for ACL injuries.

Is There a Sex Difference in Trunk Neuromuscular Control among Recreational Athletes during Cutting Maneuvers?

Trunk motion is most likely to influence knee joint injury risk, but little is known about sex-related differences in trunk neuromuscular control during changes of direction. The purpose of the present study was to test whether differences in trunk control between males and females during changes of direction exist. Twelve female and 12 male recreational athletes (with at least 10 years of experience in team sport) performed unanticipated changes of direction with 30° and 60° cut angles, while 3D trunk and leg kinematics, ground reaction forces and trunk muscles electromyography were recorded. Trunk kinematics at the time of peak knee abduction moment and directed co-contraction ratios for trunk muscles during the pre-activation and weight acceptance phases were determined. None of the trunk kinematics and co-contraction ratio variables, nor peak knee abduction moment differed between sexes. Compared to the 30° cut, trunk lateral flexion remained unchanged and trunk external rotation was reduced (p < 0.001; η²p (partial eta squared for effect size) = 0.78), while peak knee abduction moment was increased (p < 0.001; η²p = 0.84) at 60°. The sharper cutting angle induced muscle co-contraction during the pre-activation directed less towards trunk flexors (p < 0.01; η²p = 0.27) but more towards trunk medial flexors and rotators opposite to the movement direction (p < 0.001; η²p > 0.46). However, muscle co-contraction during the weight acceptance phase remained comparable between 30° and 60°. The lack of sex-related differences in trunk control does not explain knee joint injury risk discrepancies between sexes during changes of direction. Trunk neuromuscular strategies during sharper cutting angles revealed the importance of external oblique muscles to maintain trunk lateral flexion at the expense of trunk rotation. This provides new information for trunk strength training purposes for athletes performing changes of direction.

A 2D qualitative movement assessment of a deceleration task detects football players with high knee joint loading

Purpose The deceleration (pressing) is a common situational pattern leading to anterior cruciate ligament (ACL) injury in football. Although mainly assessed for performance purposes, a stronger focus on movement quality might support the screening of at-risk athletes. The aim of the present study was to describe a 2D scoring system for the assessment of the deceleration task and to associate it with the knee joint loading (knee abduction moment) evaluated through the gold standard 3D motion capture. The hypothesis was that lower 2D scores would be associated with higher knee joint loading. Methods Thirty-four competitive football (soccer) players (age 22.8 ± 4.1, 16 females) performed a series of deceleration tasks. 3D motion analysis was recorded using ten stereophotogrammetric cameras, a force platform, and three high-speed cameras. The 2D qualitative assessment was performed via a scoring system based on the video analysis of frontal and lateral planes joint kinematics for five scoring criteria. The intra- and inter-rater reliabilities were calculated for each 2D scoring criteria. The peak knee abduction moment was extracted and grouped according to the results of the 2D evaluation. Results An ICC > 0.94 was found for all the 2D scoring criteria, both for intra-rater and inter-rater reliability. The players with low 2D frontal plane scores and low total scores (0–4) showed significantly higher peak knee abduction moment values (p < 0.001). A significant negative rank correlation was found between the total score and the peak knee abduction moment (ρ = − 0.25, p < 0.001). Conclusions The qualitative 2D scoring system described successfully discerned between athletes with high and low knee joint loading during a deceleration task. The application of this qualitative movement assessment based on a detailed and accurate scoring system is suitable to identify players and patients with high knee joint loading (high knee abduction moments) and target additional training in the scenario of the primary and secondary ACL injury risk reduction. Level of evidence Level IV.

Effect of unplanned athletic movement on knee mechanics: a systematic review with multilevel meta-analysis

ObjectiveTo compare the effects of pre-planned and unplanned movement tasks on knee biomechanics in uninjured individuals.DesignSystematic review with meta-analysis.Data sourcesFive databases (PubMed, Google Scholar, Cochrane Library, ScienceDirect and Web of Science) were searched from inception to November 2020. Cross-sectional, (randomised) controlled/non-controlled trials comparing knee angles/moments of pre-planned and unplanned single-leg landings/cuttings were included. Quality of evidence was assessed using the tool of the Grading of Recommendations Assessment, Development and Evaluation working group.MethodsA multilevel meta-analysis with a robust random-effects meta-regression model was used to pool the standardised mean differences (SMD) of knee mechanics between pre-planned and unplanned tasks. The influence of possible effect modifiers (eg, competitive performance level) was examined in a moderator analysis.ResultsTwenty-five trials (485 participants) with good methodological quality (Downs and Black) were identified. Quality of evidence was downgraded due to potential risk of bias (eg, confounding). Moderate-quality evidence indicates that unplanned tasks evoked significantly higher external knee abduction (SMD: 0.34, 95% CI: 0.16 to 0.51, 14 studies) and tibial internal rotation moments (SMD: 0.51, 95% CI: 0.23 to 0.79, 11 studies). No significant between-condition differences were detected for sagittal plane mechanics (p>0.05). According to the moderator analysis, increased abduction moments particularly occurred in non-professional athletes (SMD: 0.55, 95% CI: 0.14 to 0.95, 5 studies).ConclusionUnplanned movement entails higher knee abduction and tibial internal rotation moments, which could predispose for knee injury. Exercise professionals designing injury-prevention protocols, especially for non-elite athletes, should consider the implementation of assessments and exercises requiring time-constrained decision-making.PROSPERO registration numberCRD42019140331.

Bilateral Squatting Mechanics Are Associated With Landing Mechanics in Anterior Cruciate Ligament Reconstruction Patients

Background: Proper lower extremity biomechanics during bilateral landing is important for reducing injury risk in athletes returning to sports after anterior cruciate ligament reconstruction (ACLR). Although landing is a quick ballistic movement that is difficult to modify, squatting is a slower cyclic movement that is ideal for motor learning. Hypothesis: There is a relationship between lower extremity biomechanics during bilateral landing and bilateral squatting in patients with an ACLR. Study Design: Descriptive laboratory study. Methods: A total of 41 patients after a unilateral ACLR (24 men, 17 women; 5.9 ± 1.4 months after ACLR) completed 15 unweighted bilateral squats and 10 bilateral stop-jumps. Three-dimensional lower extremity kinematics and kinetics were collected, and peak knee abduction angle, knee abduction/adduction range of motion, peak vertical ground-reaction force limb symmetry index (LSI), vertical ground-reaction force impulse LSI, and peak knee extension moment LSI were computed during the descending phase of the squatting and landing tasks. Wilcoxon signed-rank tests were used to compare each outcome between limbs, and Spearman correlations were used to compare outcomes between the squatting and landing tasks. Results: The peak vertical ground reaction force, the vertical ground reaction force impulse, and the peak knee extension moment were reduced in the surgical (Sx) limb relative to the nonsurgical (NSx) limb during both the squatting and landing tasks ( P < .001). The relationship between squatting and landing tasks was strong for the peak knee abduction angle ( R = 0.697-0.737; P < .001); moderate for the frontal plane knee range of motion (NSx: R = 0.366, P = .019; Sx: R = 0.418, P = 0.007), the peak knee extension moment LSI ( R = 0.573; P < .001), the vertical ground reaction force impulse LSI ( R = 0.382; P < .014); and weak for the peak vertical ground reaction force LSI ( R = 0.323; P = .039). Conclusion: Patients who have undergone an ACLR continue to offload their surgical limb during both squatting and landing. Additionally, there is a relationship between movement deficits during squatting and movement deficits during landing in patients with an ACLR preparing to return to sports. Clinical Relevance: As movement deficits during squatting and landing were related before return to sports, this study suggests that interventional approaches to improve squatting biomechanics may translate to improved landing biomechanics in patients with an ACLR.

NEURAL ACTIVITY AND LANDING BIOMECHANICS: EXPLORING THE RELATIONSHIPS BETWEEN THE BRAIN, BODY, AND ACL INJURY-RISK

Background: Anterior cruciate ligament (ACL) injuries predominantly occur via non-contact mechanisms, secondary to motor coordination errors resulting in aberrant frontal plane knee loads that exceed the thresholds of ligament integrity. However, central nervous system processing underlying high injury-risk motor coordination errors remain unknown, limiting the optimization of current injury reduction strategies. Purpose: To evaluate the relationships between brain activity during motor tasks with injury-risk loading during a drop vertical jump. Methods: Thirty female high school soccer players (16.10 ± 0.87 years, 165.10 ± 4.64 cm, 63.43 ± 8.80 kg) were evaluated with 3D biomechanics during a standardized drop vertical jump from a 30 cm box and peak knee abduction moment was extracted as the injury-risk variable of interest. A neuroimaging session to capture neural activity (via blood-oxygen-level-dependent signal) was then completed which consisted of 4 blocks of 30 seconds of repeated bilateral leg press action paced to a metronome beat of 1.2 Hz with 30 seconds rest between blocks. Knee abduction moment was evaluated relative to neural activity to identify potential neural contributors to injury-risk. Results: There was a direct relationship between increased landing knee abduction moment and increased neural activation within regions corresponding to the lingual gyrus, intracalcarine cortex, posterior cingulate cortex, and precuneus (r2= 0.68, p corrected < .05, z max > 3.1; Table 1 & Figure 1). Conclusion: Elevated activity in regions that integrate sensory, spatial, and attentional information may contribute to elevated frontal plane knee loads during landing. Interestingly, a similar activation pattern related to high-risk landing mechanics has been found in those following injury, indicating that predisposing factors to injury may be accentuated by injury or that modern rehabilitation does not recover prospective neural control deficits. These data uncover a potentially novel brain marker that could guide the discovery of neural-therapeutic targets that reduce injury risk beyond current prevention methods. [Table: see text][Figure: see text]