Bart Dingenen

Can two-dimensional video analysis during single-leg drop vertical jumps help identify non-contact knee injury risk? A one-year prospective study

BACKGROUND Previous studies showed that the amount of hip flexion and the combination of knee valgus and lateral trunk motion, measured with two-dimensional video analysis, were related to three-dimensional measured knee joint moments during single-leg drop vertical jumps, but it remains unclear whether these measurements can be used to identify non-contact knee injury risk. METHODS Fifty injury-free female athletes participated in the study. Two-dimensional video analysis was used to measure hip flexion, knee valgus and lateral trunk motion angles during single-leg drop vertical jumps. Time loss non-contact knee injuries were registered during a one-year follow-up. Independent t-tests and receiver operating characteristic analysis were used to analyze the predictive ability of the two-dimensional angles. FINDINGS Seven participants sustained a time loss non-contact knee injury. Hip flexion was not significantly different between groups (P>.05). The combination of knee valgus and lateral trunk motion was significantly smaller in the injured (P=.036) and non-injured legs (P=.009) of the future injured group compared with the respective matched leg of the non-injured group. The receiver operating characteristic analysis showed a significant discriminative accuracy between groups for the combination of knee valgus and lateral trunk motion of the uninjured leg of the future injured group with the matched leg of the non-injured group (area under curve=0.803; P=.012). INTERPRETATION The measurement of a combination of increased knee valgus and ipsilateral trunk motion during the single-leg drop vertical jump with two-dimensional video analysis can be used to help identify female athletes with increased non-contact knee injury risk.

A new method to analyze postural stability during a transition task from double-leg stance to single-leg stance

Time to stabilization (TTS) has been introduced as a method to analyze dynamic postural stability during jump and landing tasks, but has also been applied during the transition task from double-leg stance (DLS) to single-leg stance (SLS). However, the application of the originally described TTS technique during the latter task has some important limitations. The first goal of this study was to present an adapted version of the TTS technique to provide an effective alternative method to better analyze postural stability during the transition from DLS to SLS. The second goal was to study the influence of pathology and different speeds on postural stability outcomes. Fifteen healthy control subjects and 15 subjects with chronic ankle instability (CAI) performed the transition task on their preferred speed and as fast as possible, with eyes open and with eyes closed. Subjects with CAI performed the transition significantly slower when moving at their preferred speed with eyes closed. The time subjects needed to reach a new stability point was not discriminative between groups and largely dependent on movement speed. However, the amount of sway after this new stability point was significantly increased in the CAI group and when eyes were closed. The results of this study suggest that subjects with CAI have a decreased ability to overcome the postural perturbation created by the voluntary movement from DLS to SLS. Focusing only on TTS during the transition from DLS to SLS may lead at least in some cases to misinterpretations when assessing postural stability.

Optimization of the Return-to-Sport Paradigm After Anterior Cruciate Ligament Reconstruction: A Critical Step Back to Move Forward

Athletes who have sustained an anterior cruciate ligament (ACL) injury often opt for an ACL reconstruction (ACLR) with the goal and expectation to resume sports. Unfortunately, the proportion of athletes successfully returning to sport is relatively low, while the rate of second ACL injury has been reported to exceed 20% after clearance to return to sport, especially within younger athletic populations. Despite the development of return-to-sport guidelines over recent years, there are still more questions than answers on the most optimal return-to-sport criteria after ACLR. The primary purpose of this review was to provide a critical appraisal of the current return-to-sport criteria and decision-making processes after ACLR. Traditional return-to-sport criteria mainly focus on time after injury and impairments of the injured knee joint. The return-to-sport decision making is only made at the hypothetical ‘end’ of the rehabilitation. We propose an optimized criterion-based multifactorial return-to-sport approach based on shared decision making within a broad biopsychosocial framework. A wide spectrum of sensorimotor and biomechanical outcomes should be assessed comprehensively, while the interactions of an individual athlete with the tasks being performed and the environment in which the tasks are executed are taken into account. A layered approach within a smooth continuum with repeated athletic evaluations throughout rehabilitation followed by a gradual periodized reintegration into sport with adequate follow-up may help to guide an individual athlete toward a successful return to sport.

Can two-dimensional measured peak sagittal plane excursions during drop vertical jumps help identify three-dimensional measured joint moments?

BACKGROUND Less optimal sagittal plane movement patterns are believed to increase knee injury risk in female athletes. To facilitate clinical screening with a user-friendly method, the purpose of the present study was to examine the temporal relationships between two-dimensional measured sagittal plane kinematics and three-dimensional joint moments during the double-leg drop vertical jump (DVJ) and single-leg DVJ (SLDVJ). METHODS Fifty injury-free female athletes were tested. Maximal excursions of hip flexion, knee flexion and ankle dorsiflexion were measured through two-dimensional video analysis. Three-dimensional motion and ground reaction forces were recorded to calculate external hip flexion, knee flexion and knee abduction moments during the entire stance phase of DVJ and SLDVJ. One-dimensional statistical parametric mapping was used to examine relationships between peak two-dimensional kinematic variables and three-dimensional moment profiles. RESULTS Hip flexion was significantly related to the hip and knee flexion moment for both tests and knee abduction moment for DVJ during the time frames corresponding with highest three-dimensional moments, while knee flexion was significantly related to the hip flexion moment during these time frames. No significant relationships were found for ankle dorsiflexion with any of the joint moments. CONCLUSIONS Two-dimensional measured sagittal plane hip flexion angles at the deepest landing position were associated with peak joint moments of the hip and knee during DVJ and SLDVJ, while the amount of knee flexion was only associated with the hip flexion moment. Assessment of knee injury risk with two-dimensional video analysis could benefit from measuring maximal hip flexion, more so than knee flexion.

Postural stability deficits during the transition from double-leg stance to single-leg stance in anterior cruciate ligament reconstructed subjects.

The goal of this study was to evaluate postural stability during the transition from double-leg stance (DLS) to single-leg stance (SLS) in anterior cruciate ligament reconstructed (ACLR) (n=20) and non-injured control subjects (n=20). All ACLR subjects had fully returned to their pre-injury sport participation. Both groups were similar for age, gender, height, weight, body mass index and activity level. Spatiotemporal center of pressure outcomes of both legs of each subject were measured during the transition from DLS to SLS in eyes open and eyes closed conditions. Movement speed was standardized. The center of pressure displacement after a new stability point was reached during the SLS phase was significantly increased in the ACLR group compared to the control group in the eyes closed condition (P=.001). No significant different postural stability outcomes were found between the operated and non-operated legs. In conclusion, the ACLR group showed postural stability deficits, indicating that these persons may have a decreased ability to stabilize their body after the internal postural perturbation created by the transition from DLS to SLS. The non-operated leg may not be the best reference when evaluating postural stability of the operated leg after ACLR, as no differences were found between legs.

Effect of taping on foot kinematics in persons with chronic ankle instability

OBJECTIVES To investigate differences in rigid-foot and multi-segmental foot kinematics between healthy (control) and chronic ankle instability (CAI) participants during running and to evaluate the effect of low-Dye (LD) and high-Dye (HD) taping on foot kinematics of CAI subjects. DESIGN Cross-sectional, comparative study. METHODS Kinematic data of 12 controls and 15 CAI participants were collected by a 3D motion analysis system during running. CAI participants performed barefoot (CAI_BF) running trials as well as trials with taping. A rigid Plug-in gait Model and the Rizzoli 3D Multi-Segment Foot Model were used. Groups were compared using one-dimensional statistical parametric mapping. RESULTS An increased inversion, a decreased dorsiflexion between the foot and tibia and a decreased external foot progression angle were found during terminal swing and early stance in the CAI_BF group. With respect to the taped conditions, post-hoc SPM{t} calculations highlighted a more dorsiflexed rearfoot (38-46% running cycle) in the CAI_HD compared to the CAI_LD, and a more inverted Mid-Met angle (6-24% running cycle) in the CAI_LD compared to the CAI_BF condition. CONCLUSIONS This study revealed significant differences in rigid foot and multi-segmental foot kinematics between all groups. As high-dye taping embraces shank-rearfoot and forefoot, it seems to have better therapeutic features with respect to low-dye taping as the latter created a more inverted forefoot which may not be recommended in this population.

Lower extremity muscle activation onset times during the transition from double-leg stance to single-leg stance in anterior cruciate ligament injured subjects

The goal of this study was to evaluate muscle activation onset times (MAOT) of both legs during a transition task from double-leg stance (DLS) to single-leg stance (SLS) in anterior cruciate ligament injured (ACLI) (n=15) and non-injured control subjects (n=15) with eyes open and eyes closed. Significantly delayed MAOT were found in the ACLI group compared to the control group for vastus lateralis, vastus medialis obliquus, hamstrings medial, hamstrings lateral, tibialis anterior, peroneus longus and gastrocnemius in both vision conditions, for gluteus maximus and gluteus medius with eyes open and for tensor fascia latae with eyes closed. Within the ACLI group, delayed MAOT of tibialis anterior with eyes open and gastrocnemius with eyes closed were found in the injured leg compared to the non-injured leg. All other muscles were not significantly different between legs. In conclusion, the ACLI group showed delayed MAOT not only around the knee, but also at the hip and ankle muscles compared to the non-injured control group. No differences between both legs of the ACLI group were found, except for tibialis anterior and gastrocnemius. These findings indirectly support including central nervous system re-education training to target the underlying mechanisms of these altered MAOT after ACL injury.

Postural stability during the transition from double-leg stance to single-leg stance in anterior cruciate ligament injured subjects

BACKGROUND An anterior cruciate ligament injury may lead to deteriorations in postural stability. The goal of this study was to evaluate postural stability during the transition from double-leg stance to single-leg stance of both legs in anterior cruciate ligament injured subjects and non-injured control subjects with a standardized methodology. METHODS Fifteen control subjects and 15 anterior cruciate ligament injured subjects (time after injury: mean (SD)=1.4 (0.7) months) participated in the study. Both groups were similar for age, gender, height, weight and body mass index. Spatiotemporal center of pressure outcomes of both legs of each subject were measured during the transition from double-leg stance to single-leg stance in eyes open and eyes closed conditions. Movement speed was standardized. FINDINGS The center of pressure displacement after a new stability point was reached during the single-leg stance phase was significantly increased in the anterior cruciate ligament injured group compared to the control group in the eyes closed condition (P<.001). No significant different postural stability outcomes were found between both legs within both groups (P>.05). No significant differences were found during the transition itself (P>.05). INTERPRETATION The anterior cruciate ligament injured group showed postural stability deficits during the single-leg stance phase compared to the non-injured control group in the eyes closed condition. Using the non-injured leg as a normal reference when evaluating postural stability of the injured leg may lead to misinterpretations, as no significant differences were found between the injured and non-injured leg of the anterior cruciate ligament injured group.

Lower extremity muscle activation onset times during the transition from double-leg stance to single-leg stance in anterior cruciate ligament reconstructed subjects

BACKGROUND Previous studies mainly focused on muscles at the operated knee after anterior cruciate ligament reconstruction, less on muscles around other joints of the operated and non-operated leg. The aim of this study was to investigate muscle activation onset times during the transition from double-leg stance to single-leg stance in anterior cruciate ligament reconstructed subjects. METHODS Lower extremity muscle activation onset times of both legs of 20 fully returned to sport anterior cruciate ligament reconstructed subjects and 20 non-injured control subjects were measured during the transition from double-leg stance to single-leg stance in eyes open and eyes closed conditions. Analysis of covariance (ANCOVA) was used to evaluate differences between groups and differences between legs within both groups, while controlling for peak center of pressure velocity. FINDINGS Significantly delayed muscle activation onset times were found in the anterior cruciate ligament reconstructed group compared to the control group for gluteus maximus, gluteus medius, vastus medialis obliquus, medial hamstrings, lateral hamstrings and gastrocnemius in both eyes open and eyes closed conditions (P<.05). Within the anterior cruciate ligament reconstructed group, no significant different muscle activation onset times were found between the operated and non-operated leg (P>.05). INTERPRETATION Despite completion of rehabilitation and full return to sport, the anterior cruciate ligament reconstructed group showed neuromuscular control deficits that were not limited to the operated knee joint. Clinicians should focus on relearning multi-segmental anticipatory neuromuscular control strategies after anterior cruciate ligament reconstruction.

Mapping current research trends on anterior cruciate ligament injury risk against the existing evidence: In vivo biomechanical risk factors.

BACKGROUND Whilst many studies measure large numbers of biomechanical parameters and associate these to anterior cruciate ligament injury risk, they cannot be considered as anterior cruciate ligament injury risk factors without evidence from prospective studies. A review was conducted to systematically assess the in vivo biomechanical literature to identify biomechanical risk factors for non-contact anterior cruciate ligament injury during dynamic sports tasks; and to critically evaluate the research trends from retrospective and associative studies investigating non-contact anterior cruciate ligament injury risk. METHODS An electronic literature search was undertaken on studies examining in vivo biomechanical risk factors associated with non-contact anterior cruciate ligament injury. The relevant studies were assessed by classification; level 1 - a prospective cohort study, level 2 - a retrospective study or level 3 - an associative study. FINDINGS An initial search revealed 812 studies but this was reduced to 1 level 1 evidence study, 20 level 2 evidence studies and 175 level 3 evidence studies that met all inclusion criteria. Level 1 evidence showed that the knee abduction angle, knee abduction moment and ground reaction force were biomechanical risk factors. Nine level 2 studies and eighty-three level 3 studies used these to assess risk factors in their study. Inconsistencies in results and methods were observed in level 2 and 3 studies. INTERPRETATION There is a lack of high quality, prospective level 1 evidence related to biomechanical risk factors for non-contact anterior cruciate ligament injury. More prospective cohort studies are required to determine risk factors and provide improved prognostic capability.