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.

Lumbar spinal surgery improves locomotive syndrome in elderly patients with lumbar spinal canal stenosis: A multicenter prospective study.

BACKGROUND: Owing to musculoskeletal dysfunction, locomotive syndrome elevates the risk of requiring nursing care. Among degenerative musculoskeletal disorders, lumbar spinal canal stenosis (LSS) associates with locomotive syndrome; however, whether lumbar spinal surgery for LSS improves locomotive syndrome remains unclear. Hence, this study aimed to identify the efficacy of lumbar spinal surgery on locomotive syndrome among elderly patients with LSS. METHODS: We prospectively collected the clinical data from multiple institutions of patients (age >65 years) who underwent lumbar spinal surgery. Patients were examined for the locomotive syndrome risk test, including the stand-up Test, the two-step Test, and the 25-question risk assessment, 1-day preoperatively and 6-month and 1-year postoperatively. Using a logistic regression model, we identified factors associated with improvement of locomotive syndrome in the total assessment. RESULTS: Overall, we examined the data of 166 patients in this study. Upon converting each score of three tests to the stage of locomotive syndrome, the two-step test and the 25-question risk assessment revealed marked improvement in the postoperative distribution of stages. However, the stand-up test revealed a comparable distribution of stages pre- and postoperatively. In the total assessment, the postoperative distribution of stages was significantly improved than that preoperatively. The multivariable analysis revealed that failed back surgery syndrome [odds ratio (OR), 0.2; 95% confidence interval (CI): 0.04-1.05; P = 0.057)] and preoperative stage of 2 in stand-up test (OR, 0.2; 95% CI: 0.05-1.02; P = 0.054) tended to have inverse association with postoperative improvement of locomotive syndrome in the total assessment. CONCLUSIONS: Lumbar spinal surgery improved the stage of locomotive syndrome among elderly patients with LSS. This study suggests that lumbar spinal surgery for LSS could be beneficial in alleviating locomotive syndrome.

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.

Stride length of elderly patients with lumbar spinal stenosis: Multi-center study using the Two-Step test.

BACKGROUND: Short stride length is one of clinical symptoms associated with lumbar spinal stenosis (LSS). Short stride is a risk factor for falls; therefore, identification of factors associated with short stride is critical for fall prevention in LSS patients. Although the Two-Step test can conveniently assess maximal stride length, it has not become widely used; therefore, its data are limited. We identified the potential factors associated with short stride of elderly LSS patients using Two-Step test. METHODS: Clinical data of patients aged >65 years who planned to undergo surgery for LSS were prospectively collected at multiple institutions. Patients were assessed with the Two-Step test and Timed Up-and-Go Test prior to surgery; 357 consecutive patients were enrolled. We determined the cut-off value of the Two-Step test score for short stride, referring to the Timed Up-and-Go Test score of 13.5 s, used to indicate high risk of falls in elderly individuals. Logistic regression model was constructed to identify factors associated with short stride. RESULTS: The Two-Step test score showed moderate-to-strong inverse correlation with that of Timed Up-and-Go Test (r = -0.65, p < 0.001). Using the tentative Two-Step test cut-off value (0.93) for short stride, multivariable analysis showed that age ≥80 years (OR = 2.3, 95% CI:1.1-4.8), a score of <60 for lumbar function in Japanese Orthopedic Association Back Pain Evaluation Questionnaire (OR = 2.7, 95% CI:1.5-4.7), motor deficit (OR = 2.7, 95% CI:1.2-6.1), and sagittal vertical axis ≥50 mm (OR = 2.1, 95% CI:1.2-3.5) were factors significantly associated with short stride in elderly patients with LSS. CONCLUSIONS: Using the Two-Step test, we found that 80 years old and over, lumbar dysfunction, motor deficit of the lower extremities, and forward-bent posture were associated with short stride in LSS patients. Therefore, elderly LSS patients with these conditions may have a higher risk for falls.

Lumbar spinal canal stenosis leads to locomotive syndrome in elderly patients.

BACKGROUND: Locomotive syndrome is a condition in which the ability to lead a normal life is restricted owing to a dysfunction in one or more of the parts of the musculoskeletal system. Although lumbar spinal canal stenosis (LSS) is considered to cause locomotive syndrome, a detailed assessment of the association between two pathologies has not yet been reported. METHODS: The clinical data of patients aged > 65 years old who planned to undergo surgery for LSS at multiple institutions were prospectively collected from April 2016 to August 2017. A total of 200 participants comprising 120 men and 80 women were enrolled in this study. Association of severity of LSS evaluated by Zurich Claudication Questionnaire scores with three locomotive syndrome risk tests (Stand-up Test, the Two-step Test, and a 25-question risk assessment) and Timed Up-and-Go Test were evaluated. RESULTS: In the total assessment of locomotive syndrome, 96.5% of the participants were diagnosed as grade 2, and the remaining 3.5% were diagnosed as grade 1. When the participants were divided into 3 groups according to the LSS severity, the scores of all locomotive syndrome risk tests were significantly worse with increasing LSS severity. Logistic regression analysis revealed that LSS severity was positively correlated with the risk level of locomotive syndrome evaluated by the Two-step Test (OR = 3.45, CI = 1.33-8.96). CONCLUSIONS: All LSS patients with surgical indications were diagnosed as having locomotive syndrome. In addition, our results indicated that LSS severity is potentially associated with the progression of locomotive syndrome. The treatment of LSS may be beneficial in alleviating the risk for locomotive syndrome.

Factors affecting one-leg standing time in patients with end-stage knee osteoarthritis and the age-related recovery process following total knee arthroplasty.

BACKGROUND: The aims of the present study were to investigate the factors affecting one-leg standing (OLS) time in patients with end-stage knee osteoarthritis (OA) and to clarify the age-related recovery process following total knee arthroplasty (TKA) in the early postoperative period. METHODS: A total of 80 knees of 40 patients with knee OA were enrolled. They were asked to perform relaxed standing on one leg for as long as possible. First, OLS time was measured. Second, age, body mass index, knee flexion angle during (KFA) OLS, femorotibial angle (FTA) during OLS, and a visual analogue scale (VAS) for pain were evaluated. Multiple regression analysis was done to identify the factors affecting OLS time. In addition, the recovery process was compared between older and younger patients after TKA. RESULTS: A larger KFA during OLS, older age, and larger FTA were significantly associated with shorter OLS time. After TKA, postoperative OLS time in older patients did not improve significantly by postoperative day 20, while the time in younger patients improved significantly from postoperative day 19. CONCLUSIONS: Even if subjective knee pain and KFA during OLS improved, longer rehabilitation was required to improve OLS time in older patients in the early postoperative period.

Three-dimensional knee kinematics in patients with a discoid lateral meniscus during gait.

BACKGROUND: To date, the knee kinematics of a discoid lateral meniscus (DLM) has not been elucidated. The aim was to investigate the three-dimensional knee kinematics in knees with a DLM using gait analysis. METHODS: Ten patients (mean: 14years) diagnosed with bilateral DLM and unilaterally symptomatic snapping as well as 10 healthy controls (mean: 23years) participated in the study. Each patient with a DLM had unilaterally snapping knee in full extension and deep flexion. The three-dimensional gait analysis was performed with the point cluster technique. All subjects were asked to walk on a level floor at the speed of their choice. In the sagittal plane, knee excursion was separately evaluated during the weight acceptance phase and the mid-stance phase. In the axial plane, knee excursion during the stance phase was assessed. Finally, knee excursion during the whole gait cycle was evaluated in the frontal plane. Statistical comparison was conducted between groups, and between both sides in the DLM group. RESULTS: In the sagittal plane, knee excursions during the weight acceptance phase and the mid-stance phase were significantly smaller in the DLM group than in the control group; in addition, these were smaller on the symptomatic side than on the asymptomatic side in the DLM group. In the axial plane, knee excursion was also significantly smaller on the symptomatic side than on the asymptomatic side in the DLM group, whereas the frontal knee motion did not differ significantly. CONCLUSION: Less knee motion in the sagittal plane may prevent snapping during extension and flexion in patients with a DLM. LEVEL OF EVIDENCE: III.

Effect of unstable meniscal injury on three-dimensional knee kinematics during gait in anterior cruciate ligament-deficient patients.

BACKGROUND: Our purpose was to clarify the differences of three-dimensional knee kinematics in anterior cruciate ligament (ACL)-deficient patients between with and without meniscal injury using gait analysis. METHODS: A total of 72 knees in 36 young athletes with primary and unilateral ACL injury, with a mean age of 22 years, participated. Gait analysis was done before surgery. According to the arthroscopic findings, patients were divided into two groups. The patients with an unstable meniscal tear were allocated to the meniscal injury group (ACL+M group), and the patients without a meniscal tear were allocated to the no meniscal injury group (ACL group). In the gait analysis, three-dimensional knee kinematics was evaluated and compared. RESULTS: The patients in both groups exhibited lower sagittal plane knee excursions and peak knee extension angles on the affected limb than on the unaffected limb during the mid-stance. In terms of the axial plane, a rotation angle was significantly smaller in the affected knees than in the unaffected knees in the ACL group. On the other hand, an opposite phenomenon was observed in the ACL+M group. Moreover, a significantly larger rotation angle in the affected knees during the stance phase and the whole gait cycle was observed in the ACL+M group than in the ACL group. CONCLUSION: Increased rotational motion during the gait was observed in the ACL-deficient knees combined with unstable meniscal injuries. Meniscal condition may be a key factor for compensatory gait mechanics to prevent rotatory instability in ACL-deficient patients patients. LEVEL OF EVIDENCE: III.

Stress fracture of the first metatarsal after total knee arthroplasty: two case reports using gait analysis.

Stress fractures after total knee arthroplasty (TKA) occur mainly in patients with considerable deformity of the knee. In addition, the majority of these fractures after TKA involve the hip joint. We present two cases of stress fractures of the first metatarsal after TKA in patients with severe varus deformity. Correction of leg alignment and pain reduction obtained by TKA lead to stress fracture of the bone. Gait analysis was carried out for both cases in order to clarify the gait characteristics of the stress fracture. As a result, side-to-side differences of the distance between first metatarsal and foot center of pressure in the coronal plane were observed using gait analysis in these patients. Fortunately, conservative treatment was successful for these patients. Stress fractures should be considered when a patient who had a considerable severe deformity of the knee preoperatively complains of foot pain on the affected side. Contrary to stress fractures at the hip joint, patients with the fracture of the first metatarsal can be treated without surgery.