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 may differ with 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 two different high-resolution 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 using ANOVA or Kruskal-Wallis test after confirming normality assumption. Thereafter post hoc Tukey or Steel-Dwass was utilized for multiple comparison. RESULTS: Soccer players had better LESS score, and peak knee flexion angle was significantly larger in soccer players compared to the other sports. In addition, knee abduction angle at initial contact (IC), peak knee abduction angle, knee internal rotation angle, and knee abduction moment within 40 ms from IC were significantly smaller in soccer players, compared to basketball players. In terms of volleyball players, knee abduction angle at IC and knee internal rotation angle at IC were significantly larger than soccer players, whereas no significant biomechanical differences were found between basketball and volleyball players. CONCLUSIONS: From the present study, female basketball and volleyball players have worse LESS score, smaller peak knee flexion angle, greater knee abduction angle at IC and greater knee internal rotation angle at IC, compared to female soccer players. Thus, female basketball and volleyball players may have an increased risk of non-contact ACL injury during the jump-landing task, compared to soccer players. Biomechanics of DVJ depends on characteristics of the athlete's primary sport.

Effects of Dual Task Interference on Biomechanics of The Entire Lower Extremity During the Drop Vertical Jump.

The dual task is an important factor affecting knee biomechanics during jump-landing tasks. Athletes often have trouble in performing two tasks concurrently and a dual task can deteriorate landing performance. However, it is still unknown whether a dual task will affect the entire lower extremity. The purpose of this study was to clarify the effects of cognitive task interference on biomechanics of hip and ankle joints as well as the knee joint during the drop vertical jump (DVJ). A total of 20 female collegiate athletes participated in the study. Athletes performed a DVJ with or without a cognitive task. The DVJ was captured using a motion analysis system. Mental arithmetic of 2-digit addition was used as a cognitive task. Maximum vertical ground reaction force (vGRF), joint angles at initial contact (IC), joint moments within 40 milliseconds (ms) after IC, and joint angles and moments at peak vGRF were assessed. The data were statistically compared between with and without a cognitive task condition using a two-tailed paired t-test or the Wilcoxon singed rank test. The peak external knee abduction moment on both limbs within 40 ms after IC during the DVJ was significantly larger in the dual task than in the single task with less knee and hip flexion at initial contact. In addition, all moments of hip and ankle joints within 40 ms after IC were significantly larger in the dual task than in the single task accompanied with greater vGRF, except for the hip internal rotation moment. Cognitive tasks during a DVJ will result in biomechanical changes of the entire lower extremity in female athletes.

Four-dimensional computed tomographic analysis of screw home movement in patients with anterior cruciate ligament deficient knee - a 3D-3D registration technique.

OBJECTIVE: The tibia externally rotates to the femur during the last 20° of the knee extension motion. This kinematic phenomenon is well known as screw home movement (SHM). The purpose was to clarify the SHM in anterior cruciate ligament deficient (ACLD) knee using four-dimensional computed tomography (4DCT). MATERIALS AND METHODS: Six patients with a unilateral isolated ACLD knee participated. In the static position, CT scan of the both limbs of the femur and tibia were performed. Then, 4DCT was performed around knee. In the CT gantry, subjects were positioned in supine position with 45° of knee flexion on a triangle pillow and were asked to extend the knee to full extension within 10 s on each limb. The CT data were accumulated in digital imaging and communication in medicine (DICOM) data format. From the static CT and 4DCT DICOM data, three-dimensional surfaces of the knee joint were reconstructed. The whole tibia surface was matched into the partial tibia surface of that frame using 3D-3D registration technique. After the assessment of coordination system of the whole leg, knee flexion, abduction, and external rotation angle were calculated. RESULTS: Knee external rotation angle was significantly smaller on the ACLD side than on the contralateral unaffected side in 0-15° of knee flexion (P < 0.05 in 0, 5, 10, and 15 degrees), while the angle was similar during 15-60° of knee flexion. CONCLUSION: The absence of SHM in ACLD knee was detected using 3D-3D registration technique based on 4DCT.

Fatigue and recovery have different effects on knee biomechanics of drop vertical jump between female collegiate and recreational athletes.

BACKGROUND: Although fatigue is known as one of the risk factors for noncontact anterior cruciate ligament injury, the effects of fatigue and recovery can be different based on the level of competition. However, it is unknown whether female recreational athletes are susceptible to fatigue or not, compared to female collegiate athletes with greater physical activity. The purpose of the present study was to examine and clarify the effects of fatigue and recovery on knee biomechanics of the drop vertical jump (DVJ) in female recreational athletes compared to female collegiate athletes. METHODS: Fifteen female collegiate athletes and ten female recreational athletes were enrolled in the current study. All subjects were basketball players and Tegner activity scales were level 9 and 7, respectively. They performed DVJ before and after the fatigue protocol. Three-dimensional knee kinematics and kinetics were collected during landing phase of DVJ. The data after the fatigue protocol (first, second, and third DVJs) were compared with those before the protocol using one-way repeated measures of analysis of variance in each group. RESULTS: Fatigue caused significant increase of knee abduction angle at initial contact (IC) and peak abduction moments within 40 ms from IC in female recreational athletes, whereas no increases of these parameters were observed in female collegiate athletes. Moreover, recovery from fatigue seemed to be more slowly in female recreational athletes than in female collegiate athletes as smaller knee flexion moment was observed even in post-fatigue third DVJ only for female recreational athletes. CONCLUSIONS: Effects of fatigue on DVJ were significantly greater and continued for a longer duration in female recreational athletes compared to female collegiate athletes.

Correlation between weight-bearing asymmetry and bone mineral density in patients with bilateral knee osteoarthritis.

BACKGROUND: Although unloading of the joint is related to reduction of the local bone mineral density (BMD), little attention had been paid to the relationship between loading asymmetry and side-to-side difference of BMD in patients with bilateral knee osteoarthritis (OA). The aim of the present study was to evaluate and clarify the relationship between gait parameters and bone mineral density in those patients. METHODS: A total of 36 knees in eighteen patients (mean age = 73.7 ± 6.3 years, mean body mass index = 26.7 ± 3.8 kg/m2) with bilateral medial knee OA were enrolled in the present study. All subjects performed relaxed standing and level walking at our gait laboratory after informed consent was obtained. First, ground reaction force was calculated on bilateral knees during standing. The knees in each patient were divided into higher and lower force side for the definition of dominant side limb. Second, gait parameters in each subject were obtained. To analyze the factors that affect the weight-bearing distribution in both limbs, clinical data and biomechanical parameters were compared between knees. Clinical data included radiographic OA grade, femorotibial angle, and BMD at the bilateral femoral neck. RESULTS: Knees on higher force side were significantly more extended than on lower force side in standing (P = 0.012) and knee excursion during weight acceptance phase in gait was significantly larger in higher side than in lower side (P = 0.006), while the other parameters were not significantly different. As to the clinical data, higher force side had greater BMD, compared to lower force side. In terms of Kellgren-Lawrence scale and femorotibial angle on plain radiographs, there were no significant differences between higher and lower force side. CONCLUSIONS: Based on loading asymmetry in the present study, lower BMD was observed on Lower force side in patients with knee OA. Therefore, it is helpful for orthopedic surgeons to examine side-to-side differences of bone mineral density or extension limitation during standing for evaluation of the loading condition in patients with bilateral knee OA.

A comparison of gait characteristics between posterior stabilized total knee and fixed bearing unicompartmental knee arthroplasties.

BACKGROUND/OBJECTIVE: According to previous studies, physiological gait pattern was found in unicompartmental knee arthroplasty (UKA) as compared to total knee arthroplasty (TKA) concerning the gait parameters including gait speed, cadence, and step length. However, little attention had been paid to the detailed kinematic and kinetic differences during gait between TKAs and UKAs. The aim of the present study was to investigate and to clarify the biomechanical differences between posterior stabilized TKAs and fixed bearing UKAs during walking. METHODS: A total of 28 patients participated in the present study. Fifteen patients who underwent TKA and thirteen patients who underwent UKA were enrolled. Gait analysis was done at an average of 12.9 months after surgery. The subjects performed level walking at a preferred speed. For each subject, three-dimensional kinematic, kinetic and ground reaction force data were recorded as well as clinical data including range of motion at the knee joint and plain radiographs. Differences of knee kinematics or kinetics were compared between TKAs and UKAs using two-tailed Mann Whitney U-test. RESULTS: On physical examination, passive range motion was significantly smaller in TKAs than in UKAs, while femorotibial angle on plain radiographs was not significantly different on plain radiographs. In terms of kinematics, TKAs were more flexed at heel contact and less extended in mid-stance phase compared to UKAs in the sagittal plane, and total excursion of TKAs were also smaller than UKAs. Regarding knee kinetics, TKA patients had significantly less peak tibial internal rotation moment in terminal stance phase. In addition, peak knee adduction moment was significantly larger in UKAs than in TKAs, while peak knee flexion moment was not significantly different. CONCLUSION: Posterior stabilized TKAs exhibited less peak tibial internal rotation moment, which is known as pivot shift avoidance gait, in the present study, compared to fixed bearing UKAs. TKAs had similar gait pattern to anterior cruciate ligament deficient knees, compared to UKAs even if patients with TKAs had no subjective pain during walking.

Effects of Toe Direction on Biomechanics of Trunk, Pelvis, and Lower-Extremity During Single-Leg Drop Landing.

CONTEXT: Toe direction is an important factor affecting knee biomechanics during various movements. However, it is still unknown whether toe direction will affect trunk and pelvic movements. OBJECTIVE: To examine and clarify the effects of toe directions on biomechanics of trunk and pelvis as well as lower-extremities during single-leg drop landing (SLDL). DESIGN: Descriptive laboratory study. SETTING: Research laboratory. PARTICIPANTS: A total of 27 male recreational-level athletes. INTERVENTION(S): Subjects performed SLDL under 3 different toe directions, including 0° (toe neutral), 20° (toe-in [TI]), and -20° (toe-out). SLDL was captured using a motion analysis system. Nondominant leg (27 left) was chosen for the analysis. MAIN OUTCOME MEASURES: Peak values of kinematic and kinetic parameters during landing phase were assessed. In addition, those parameters at the timing of peak vertical ground reaction force were also assessed. The data were statistically compared among 3 different toe directions using 1-way repeated measures of analysis of variance or Friedman χ2 r test. RESULTS: Peak knee abduction angle and moment in TI were significantly larger than in toe neutral and toe-out (P < .001). Moreover, peak greater anterior inclination, greater inclination, and rotation of trunk and pelvis toward the nonlanding side were seen in TI (P < .001). At the timing of peak vertical ground reaction force, trunk inclined to the landing side with larger knee abduction angle in TI (P < .001). CONCLUSIONS: Several previous studies suggested that larger knee abduction angle and moment on landing side as well as trunk and pelvic inclinations during landing tasks were correlated with knee ligament injury. However, it is still unknown concerning the relationship between toe direction and trunk/pelvis movements during landing tasks. From the present study, TI during SLDL would strongly affect biomechanics of trunk and pelvis as well as knee joint, compared with toe neutral and toe-out.

Difference in leg asymmetry between female collegiate athletes and recreational athletes during drop vertical jump.

BACKGROUND: Neuromuscular imbalance will lead to loading asymmetry in sporting activities. This asymmetry is related to leg dominance, which has been associated with increased risk of anterior cruciate ligament (ACL) injury. Therefore, potential biomechanical differences between legs are important. However, little attention has been paid to the biomechanical details of leg dominance. The purpose of the present study was to clarify the relationship between leg dominance and knee biomechanics in females with different activity level during dynamic athletic tasks. METHODS: A total of 23 female collegiate (mean age = 19.6 ± 1.4 years, mean body mass index = 21.5 ± 0.9) and 19 recreational athletes (mean age = 20.7 ± 1.1 years, mean body mass index = 20.5 ± 1.7) were enrolled. Tegner activity scores of the collegiate and recreational athletes were 9 and 7, respectively. Knee kinematic and kinetic asymmetries between the dominant (DL) and non-dominant (NDL) legs during the landing phase of drop vertical jump (DVJ) were assessed using three-dimensional motion analysis in collegiate and recreational athletes separately. Statistical comparison was done using two-tailed paired t test between DL and NDL in each athlete. RESULTS: The peak knee abduction angle was significantly larger on the DL than on the NDL in collegiate athletes. Knee abduction angle at initial contact (IC), peak knee abduction angle, knee internal rotation angle at IC, and peak knee internal rotation angle were significantly larger on the NDL than on the DL in recreational athletes. Moreover, peak knee abduction moment within 40 ms from IC was larger on the NDL than on the DL in recreational athletes, while the moment was not significantly different in collegiate athletes. CONCLUSIONS: From the present study, the relationship between leg dominance and knee biomechanics was totally different in females with different activity level. Specifically, asymmetry of the knee abduction angle between limbs was opposite between female recreational and collegiate athletes. According to previous literatures, abduction and internal rotation angles as well as abduction moment were key issues for mechanism of non-contact ACL injury. Therefore, the NDL in female recreational athletes was associated with increased risk of ACL injury.

Four-Dimensional CT Analysis Using Sequential 3D-3D Registration.

Four-dimensional computed tomography (4DCT) provides a series of volume data and visualizes joint motions. However, numerical analysis of 4DCT data remains difficult because segmentation in all volumetric frames is time-consuming. We aimed to analyze joint kinematics using a sequential 3D-3D registration technique to provide the kinematics of the moving bone with respect to the fixed bone semiautomatically using 4DCT DICOM data and existing software. Surface data of the source bones are reconstructed from 3DCT. The trimmed surface data are respectively matched with surface data from the first frame in 4DCT. These trimmed surfaces are sequentially matched until the last frame. These processes provide positional information for target bones in all frames of the 4DCT. Once the coordinate systems of the target bones are decided, translation and rotation angles between any two bones can be calculated. This 4DCT analysis offers advantages in kinematic analyses of complex structures such as carpal or tarsal bones. However, fast or large-scale motions cannot be traced because of motion artifacts.

Biomechanical correlation at the knee joint between static lunge and single-leg drop landing - a comparative study among three different toe directions.

BACKGROUND: Toe direction is a critical factor affecting knee biomechanics during various movements including closed kinetic chain (CKC) exercise and landing tasks. Physiotherapists always concentrate on the control of toe direction during CKC exercise as a first step for athletes, as it is believed that correction of toe direction during CKC exercise is important to maintain the appropriate toe position even in high demanding activities such as landing tasks. The purpose of the present study was to investigate knee biomechanics during CKC exercise as well as landing tasks with three different toe directions, and clarify whether biomechanical parameters during CKC exercise would be related to those during landing tasks. METHODS: A total of 23 male recreational level athletes (mean age = 20.0 ± 1.1 yrs) participated. Tegner activity score were 7 for all male subjects. First, the subjects performed weight-bearing static lunge tests (SL) under three different toe directions, including 0 degrees (Toe-neutral: TN), 20 degrees (Toe-In: TI), and - 20 degrees (Toe-out: TO). Thereafter, SLDL was done under three different toe directions. Three-dimensional knee kinematics and kinetics at 60 degrees of knee flexion were calculated. As a statistical analysis, Pearson's correlation coefficient was used to evaluate the relationship between SL and SLDL. The statistical significance level wasset at P=0.05. RESULTS AND CONCLUSIONS: Knee abduction angle showed significant correlation between SL and SLDL in all three different directions (TI: r=0.631, p<0.001, TN: r=0.678, p<0.001, TO: r=0.572, p<0.001). In terms of knee internal rotation, strong correlation was also found (TI: r=0.846, p<0.001, TN: r=0.791, p<0.001, TO: r=0.749, p<0.001). In addition, external knee abduction moment presented significant correlation in all three different directions (TI: r=0.574, p<0.001, TN: r=0.499, p<0.01, TO: r=0.469, p<0.01). From the present study, significant correlation between SL and SLDL was found in knee abduction angle, knee internal rotation, and external knee abduction moment under all three different directions including TI, TN, and TO. Physiotherapist should take care of toe direction and reform the movements especially for athletes who present malalignment of the knee joint during SL with TI or TO to prevent ACL injury in landing tasks.

The effects of toe direction on three-dimensional knee kinematics during closed kinetic chain exercise in patients with anterior cruciate ligament deficient knee.

BACKGROUND/OBJECTIVE: Closed Kinetic Chain Exercise (CKC Ex) is a safe rehabilitation method for anterior cruciate ligament deficient (ACLD) and reconstructed knees. However, CKC Ex can be risky based on abnormal toe directions. The purpose was to investigate knee kinematics during CKC Ex under three toe directions in ACLD. METHODS: Twenty patients with unilateral ACL injury participated. The subjects performed five weight-bearing-static lunge tests on each limb under three toe directions, including 0 degrees (TN), 20 degrees (TI), and -20 degrees (TO). Three-dimensional knee kinematics were calculated using three-dimensional motion analysis system and were compared among three different toe directions. RESULTS: Among three different toe directions, peak values of knee valgus and external rotation on ACLD side were significantly larger in TO than in TN and TI. In addition, the total excursion in the coronal plane on ACLD side was significantly larger in TO than in TN and TI. Regarding the differences between ACLD and ACLI, peak values of internal rotation angle was significantly smaller in ACLD than in ACLI. CONCLUSION: From the present results, tibial rotation and knee abduction were strongly affected by toe direction. When considering a safe rehabilitation, it would be better to avoid TI and TO in CKC Ex in patients with unilateral ACL injury.

What are the important surgical factors affecting the wound healing after primary total knee arthroplasty?

BACKGROUND: Wound condition after primary total knee arthroplasty (TKA) is an important issue to avoid any postoperative adverse events. Our purpose was to investigate and to clarify the important surgical factors affecting wound score after TKA. METHODS: A total of 139 knees in 128 patients (mean 73 years) without severe comorbidity were enrolled in the present study. All primary unilateral or bilateral TKAs were done using the same skin incision line, measured resection technique, and wound closure technique using unidirectional barbed suture. In terms of the wound healing, Hollander Wound Evaluation Score (HWES) was assessed on postoperative day 14. We performed multiple regression analysis using stepwise method to identify the factors affecting HWES. Variables considered in the analysis were age, sex, body mass index (kg/m(2)), HbA1C (%), femorotibial angle (degrees) on plain radiographs, intraoperative patella eversion during the cutting phase of the femur and the tibia in knee flexion, intraoperative anterior translation of the tibia, patella resurfacing, surgical time (min), tourniquet time (min), length of skin incision (cm), postoperative drainage (ml), patellar height on postoperative lateral radiographs, and HWES. HWES was treated as a dependent variable, and others were as independent variables. RESULTS: The average HWES was 5.0 ± 0.8 point. According to stepwise forward regression test, patella eversion during the cutting phase of the femur and the tibia in knee flexion and anterior translation of the tibia were entered in this model, while other factors were not entered. Standardized partial regression coefficient was as follows: 0.57 in anterior translation of the tibia and 0.38 in patella eversion. CONCLUSIONS: Fortunately, in the present study using the unidirectional barbed suture, major wound healing problem did not occur. As to the surgical technique, intraoperative patella eversion and anterior translation of the tibia should be avoided for quality cosmesis in primary TKA.

What are the important manoeuvres for beginners to minimize surgical time in primary total knee arthroplasty?

PURPOSE: It was hypothesized that surgical time of beginners would be much longer than that of experts. Our purpose was to investigate and clarify the important manoeuvres for beginners to minimize surgical time in primary total knee arthroplasty (TKA) as a multicentre study. METHODS: A total of 300 knees in 248 patients (averaged 74.6 years) were enrolled. All TKAs were done using the same instruments and the same measured resection technique at 14 facilities by 25 orthopaedic surgeons. Surgeons were divided into three surgeon groups (four experts, nine medium-volume surgeons and 12 beginners). The surgical technique was divided into five phases. Detailed surgical time and ratio of the time in each phase to overall surgical time were recorded and compared among the groups in each phase. A total of 62, 119, and 119 TKAs were done by beginners, medium-volume surgeons, and experts, respectively. RESULTS: Significant differences in surgical time among the groups were seen in each phase. Concerning the ratio of the time, experts and medium-volume surgeons seemed cautious in fixation of the permanent component compared to other phases. Interestingly, even in ratio, beginners and medium-volume surgeons took more time in exposure of soft tissue compared to experts. (0.14 in beginners, 0.13 in medium-volume surgeons, 0.11 in experts, P < 0.05). CONCLUSION: Beginners took more time in exposure and closure of soft tissue compared to experts. Improvement in basic technique is essential to minimize surgical time among beginners. First of all, surgical instructors should teach basic techniques in primary TKA for beginners. LEVEL OF EVIDENCE: Therapeutic studies, Level IV.