Temporal validation of a clinical prediction rule for distinguishing locomotive syndromes in community-dwelling older adults: A cross-sectional study from the DETECt-L study.

Objectives: Clinical prediction rules are used to discriminate patients with locomotive syndrome and may enable early detection. This study aimed to validate the clinical predictive rules for locomotive syndrome in community-dwelling older adults. Methods: We assessed the clinical prediction rules for locomotive syndrome in a cross-sectional setting. The age, sex, and body mass index of participants were recorded. Five physical function tests-grip strength, single-leg standing time, timed up-and-go test, and preferred and maximum walking speeds-were measured as predictive factors. Three previously developed clinical prediction models for determining the severity of locomotive syndrome were assessed using a decision tree analysis. To assess validity, the sensitivity, specificity, likelihood ratio, and post-test probability of the clinical prediction rules were calculated using receiver operating characteristic curve analysis for each model. Results: Overall, 280 older adults were included (240 women; mean age, 74.8 ± 5.2 years), and 232 (82.9%), 68 (24.3%), and 28 (10.0%) participants had locomotive syndrome stages ≥ 1, ≥ 2, and = 3, respectively. The areas under the receiver operating characteristics curves were 0.701, 0.709, and 0.603, in models 1, 2, and 3, respectively. The accuracies of models 1 and 2 were moderate. Conclusions: These findings indicate that the models are reliable for community-dwelling older adults.

Functional electrostimulation therapy for vastus medialis decreases the varus thrust during gait.

[Purpose] This study aimed to investigate whether modification of vastus medialis activity can delay the varus thrust. [Participants and Methods] Ten participants (Kellgren-Laurence grades I: n=2, II: n=6, and III: n=2) diagnosed with knee osteoarthritis were enrolled. The intervention involved free walking on a 10-m walkway at any speed after donning a functional electrical stimulation set to contract the vastus medialis before heel contact. Using a Vicon Nexus ground reaction force meter and a wireless electromyograph DELSYS, varus thrust, maximal knee extension angle, maximal knee adduction moment, and vastus medialis onset time were assessed both before and after intervention. [Results] A significant difference in varus thrust was detected from before to after the intervention (2.7 ± 1.1° vs. 2.2 ± 1.3°). Both the vastus medialis activation time (-0.06 ± 0.09 vs. -0.21 ± 0.1) and the knee-joint extension angle (8.7 ± 5.1° vs. 5.5 ± 5.9°) decreased following intervention, whereas the knee adduction moment significantly increased (0.50 ± 0.20° vs 0.56 ± 0.18°). [Conclusion] Wearing the functional electrical stimulation set caused the vastus medialis to act earlier in response to heel strike, thereby improving the knee-joint extension angle and suppressing varus thrust.

Differences in lower-limb biomechanics during single-leg landing considering two peripheral fatigue tasks.

Dynamic knee valgus (DKV) occurs during landing after a fatigue task involving the lower extremity. However, the manner in which different peripheral fatigue tasks affect DKV remains unknown. In this study, we investigated the DKV via electromyography during single-leg landing considering the hip-joint fatigue task (HFT) and knee-joint fatigue task (KFT) performed by healthy men. We recruited 16 healthy male participants who performed a single-leg jump-landing motion from a height of 20 cm before and after an isokinetic hip abduction/adduction task (HFT) and knee extension/flexion task (KFT). Three-dimensional motion analysis systems were attached to the left gluteus medius and quadriceps, and surface electromyography was used to analyze the lower limb kinematics, kinetics, and muscle activity. The primary effects and interactions of the task and fatigue were identified based on the two-way repeated-measures analysis of variance. The results of the average angle during landing indicated that DKV occurs in KFT, whereas HFT applies external forces that adduct and internally rotate the knee at peak vertical ground reaction force (vGRF). Furthermore, both KFT and HFT exhibited an increase in muscle activity in the quadriceps. The analysis revealed that the occurrence of DKV varies depending on the peripheral fatigue task, and the effects on average DKV during landing and DKV at peak vGRF vary depending on the peripheral fatigue task.

Dependence on visual information in patients with ACL injury for multi-joint coordination during single-leg squats: a case control study.

BACKGROUND: The influence of vision on multi-joint control during dynamic tasks in anterior cruciate ligament (ACL) deficient patients is unknown. Thus, the purpose of this study was to establish a new method for quantifying neuromuscular control by focusing on the variability of multi-joint movement under conditions with different visual information and to determine the cutoff for potential biomarkers of injury risk in ACL deficient individuals. METHODS: Twenty-three ACL deficient patients and 23 healthy subjects participated in this study. They performed single-leg squats under two different conditions: open eyes (OE) and closed eyes (CE). Multi-joint coordination was calculated with the coupling angle of hip flexion, hip abduction and knee flexion. Non-linear analyses were performed on the coupling angle. Dependence on vision was compared between groups by calculating the CE/OE index for each variable. Cutoff values were calculated using ROC curves with ACL injury as the dependent variable and significant variables as independent variables. RESULTS: The sample entropy of the coupling angle was increased in all groups under the CE condition (P < 0.001). The CE/OE index of coupling angle variability during the descending phase was higher in ACL deficient limbs than in the limbs of healthy participants (P = 0.036). The CE/OE index of sample entropy was higher in the uninjured limbs of ACL deficient patients than in the limbs of healthy participants (P = 0.027). The cutoff value of the CE/OE index of sample entropy was calculated to be 1.477 (Sensitivity 0.957, specificity 0.478). CONCLUSION: ACL deficient patients depended on vision to control multiple joint movements not only on the ACL deficient side but also on the uninjured side during single leg squat task. These findings underscore the importance of considering visual dependence in the assessment and rehabilitation of neuromuscular control in ACL deficient individuals.

Influence of time from injury to surgery on knee biomechanics during walking in patients with anterior cruciate ligament reconstruction.

The pilot study aimed to determine whether the time from injury to surgery influences on postoperative knee biomechanics during walking in patients with anterior cruciate ligament reconstruction (ACLR). Thirty-two patients with unilateral ACLR (early, 10 patients; delayed, 22 patients) and 30 control subjects participated in this study. All examinations for patients with ACLR were performed preoperatively and at 12 months postoperatively and comprised passive knee joint laxity, knee muscle strength, and knee kinematics and kinetics during walking. At both time points, there were no significant differences in passive knee joint laxity and knee muscle strength between the early ACLR and delayed ACLR groups. Preoperatively, both the early ACLR and delayed ACLR patients exhibited significantly reduced knee extension movement from midstance to terminal stance compared to the control subjects. Moreover, the delayed ACLR patients exhibited significantly decreased peak external knee flexion moment compared to the control subjects. At 12 months postoperatively, the early ACLR patients showed significant improvement in knee extension movement from midstance to terminal stance compared to pre-ACLR, while the delayed ACLR patients did not show significant improvement in this knee extension movement. It can be concluded that early ACLR may be more beneficial to improve knee biomechanics during walking.

Detecting side-to-side differences of lower limb biomechanics during single-legged forward landing after anterior cruciate ligament reconstruction.

BACKGROUND: Motion analysis can be used to evaluate functional recovery after anterior cruciate ligament (ACL) reconstruction; however, the biomechanics parameters of the lower limb that are specifically altered in ACL-reconstructed knees compared to the contralateral side are not well understood. This retrospective study aimed to compare side-to-side differences in lower limb biomechanics during the first 100 milliseconds (ms) after initial contact in a single-leg forward landing task. METHODS: Using three-dimensional motion analysis, lower joint kinematic and kinetic variables were measured 8-10 months postoperatively in 22 patients who had undergone ACL reconstruction. We determined side-to-side differences in lower limb biomechanics over the 100-ms timeframe after landing, and receiver operating characteristic (ROC) curve analyses were performed to calculate the area under the curve (AUC) for parameters showing significant side-to-side differences. RESULTS: During the 100-ms timeframe after landing, 58 kinematic and kinetic items showed significant side-to-side differences. Side-to-side differences in lower limb biomechanics over the 40-ms timeframe after landing existed. The ROC curve analysis identified 11 items with AUC values ≥ 0.70, including hip flexion, abduction moment, and knee joint power, and their AUC values were not significantly different. CONCLUSION: Hip flexion/abduction moment and knee power after GRF max could be used as outcomes for assessing functional recovery in patients who have undergone ACL reconstruction.

Current Status and Challenges of Support Environments for New Graduate Occupational Therapists in Japanese Hospitals: A Mixed Method Study.

Introduction: The number of occupational therapists in Japan continues to increase, which has led to an urgent need to improve the educational environment for new graduate occupational therapists. This study attempted to identify the current state and challenges of the educational environment for new graduate occupational therapists in Japan. Methods: We employed a mixed method using quantitative and qualitative data from a questionnaire survey of 1055 chief occupational therapists in Japanese hospitals. The questionnaire consisted of (1) basic information about the respondent and their hospital, (2) educational environment for new graduate occupational therapists at the respondent's hospital, (3) time spent on in-hospital lectures and on-the-job training, and (4) challenges in the clinical education of new graduate occupational therapists. Text data was analysed qualitatively using text mining to create cooccurrence networks. Results: A total of 385 responses were obtained with a response rate of 36.5%. All hospitals had recruited new graduate occupational therapists in the last five years, but more than half of them did not have a philosophy and policy on education and had not prepared guidelines for the completion of occupational therapy education. The cooccurring network of issues in the educational environment for new graduate occupational therapists indicates the need to create standard guidelines, train supervisors, and develop a hospital education system. Conclusion: In the future, the needs of the educational environment for newly graduated occupational therapists should be investigated, and standardised educational guidelines should be developed.

Effects of limited previously acquired information about falling height on lower limb biomechanics when individuals are landing with limited visual input.

BACKGROUND: Inhibitions in the acquisition of accurate information about the environment can affect control of the lower extremities and lead to anterior cruciate ligament injury. This study aimed to clarify the effects of limited prior knowledge of the height of the fall, as well as limited visual input, on lower limb and trunk motion and ground reaction force during landing. METHODS: Twenty healthy university students were recruited. Drop landings from a 30-cm platform were measured under three conditions: (1) unknown, without prior knowledge of the height of the fall and without visual input; (2) known, with prior knowledge of the height of the fall and without visual input; and (3) control, with prior knowledge of the height of the fall and visual input. FINDINGS: In the unknown condition, the peak ground reaction force for the vertical and posterior directions was significantly higher than that in the known and control conditions; leg and knee stiffness, ankle joint work, and joint flexion motion of the knee, ankle, and trunk after landing were decreased as well. In the known condition, there were no significant differences in leg and knee stiffness and vertical ground reaction force compared to the control condition. INTERPRETATION: The results of this study indicate that the risk of anterior cruciate ligament injury during landing increases when individuals have limited visual input and prior knowledge of the height of the fall. This finding suggests that an accurate perception of the surrounding environment may help prevent anterior cruciate ligament injuries.

Effects of assigning physical therapists exclusively to the acute-phase stroke patient ward.

[Purpose] In April 2014, an additional health insurance system aiming to maintain or improve activities of daily living levels was newly established by the Japanese government. The purpose of this study was to determine the influence of this new medical system for rehabilitation on patient management (e.g., activities of daily living level and length of hospital stay) in an acute-phase stroke patient ward. [Participants and Methods] All patients were admitted to the stroke patient ward in our hospital and were registered between January 2012 and December 2019. We assessed the differences in the time to initiation of rehabilitation, length of hospitalization, implementation rate of rehabilitation, and Barthel Index between the period before the start of the new medical system (Prior period) and after this system was started (Post period). [Results] Significant improvements were observed in the initiation of rehabilitation and the difference in the Barthel Index scores after the start of the new medical system. Although the length of hospitalization and implementation rate of rehabilitation did not differ significantly, both indicators gradually improved after the start of the new system. [Conclusion] Our results suggest that the new medical system for rehabilitation is beneficial for patient management in the acute-phase stroke patient ward.

Decreased Muscle-to-Fat Mass Ratio Is Associated with Low Muscular Fitness and High Alanine Aminotransferase in Children and Adolescent Boys in Organized Sports Clubs.

Decreased muscle-to-fat mass ratio (MFR) is associated with pediatric nonalcoholic fatty liver disease (NAFLD) and may reduce muscular fitness. Regular exercise in sports clubs has not led to reductions in obesity in children and adolescents; they may have decreased MFR. Decreased MFR could cause reduced muscular fitness, which may put them at risk for NAFLD development. We investigated whether MFR is related to muscular fitness and serum alanine aminotransferase (ALT), to determine whether MFR could be used to screen for NAFLD in children and adolescent boys belonging to sports clubs. Altogether, 113 participants (aged 7-17 years) who underwent body composition, laboratory, and muscular fitness measurements during a medical checkup were divided into tertiles according to their MFR. Lower extremity muscular fitness values were significantly decreased in the lowest MFR tertile (p < 0.001); conversely, serum ALT levels were significantly increased (p < 0.01). Decreased MFR significantly increased the risk of elevated ALT, which requires screening for NAFLD, after adjusting for age, obesity, muscular fitness parameters, and metabolic risk factors (odds ratio = 8.53, 95% confidence interval = 1.60-45.6, p = 0.012). Physical fitness and body composition assessments, focusing on MFR, can be useful in improving performance and screening for NAFLD in children and adolescents exercising in sports clubs.

Altered Resting-State Connectivity with Pain-Related Expectation Regions in Female Patients with Severe Knee Osteoarthritis.

PURPOSE: Expectation affects pain experience in humans. Numerous studies have reported that pre-stimulus activity in the anterior insular cortex (aIC), together with prefrontal and limbic regions, integrated pain intensity and expectations. However, it is unclear whether the resting-state functional connectivity (rs-FC) between the aIC and other brain regions affects chronic pain. The purpose of this study was to examine the rs-FC between the aIC and the whole brain regions in female patients with severe knee osteoarthritis (OA). PATIENTS AND METHODS: Nineteen female patients with chronic severe knee OA and 15 matched controls underwent resting-state functional magnetic resonance imaging. We compared the rs-FC from the aIC seed region between the two groups. A disease-specific measurement of knee OA was performed. RESULTS: The aIC showed stronger rs-FC with the right orbitofrontal cortex (OFC), subcallosal area, and bilateral frontal pole compared with controls. The strength of rs-FC between the left aIC and the right OFC was positively correlated with the knee OA pain score (r = 0.49, p = 0.03). The strength of rs-FC between the right aIC and right OFC was positively correlated with the knee OA total score (r = 0.48, p = 0.036) and pain score (r = 0.46, p = 0.049). The OFC, subcallosal area, and frontal pole, together with the aIC, were activated during anticipation of pain stimulus. These areas have been reported as representative pain-related expectation regions. CONCLUSION: This was the first study to show the stronger rs-FCs between the aIC and other pain-related expectation regions in female patients with severe knee OA. Female sex and preoperative pain intensity are risk factors of persistent postoperative pain after total knee arthroplasty. It is suggested that the functional relationship between pain-related expectation regions affects the formation of severe knee OA and persistent postoperative pain following total knee arthroplasty.

Factors associated with dynamic knee valgus angle during single-leg forward landing in patients after anterior cruciate ligament reconstruction.

BACKGROUND: A few studies have reported on how to predict increased dynamic knee valgus angle (KVA), a risk factor for second anterior cruciate ligament (ACL) injury after ACL reconstruction. This study aimed to identify the factors with the potential to predict the KVA during single-leg hop landing. METHODS: Using three-dimensional motion analysis systems, knee motion during a single-leg hop landing task was measured in 22 patients who had undergone ACL reconstruction at 8-10 months postoperatively. The KVA at initial contact (IC) and maximum KVA during the 40-ms period after IC were calculated using the point cluster technique; correlations between the KVA and other factors were assessed. We performed multiple regression analysis to determine whether KVA could be predicted by these parameters. RESULTS: The KVA was significantly negatively correlated with the static femorotibial angle (FTA; P < 0.01) and patient height (P < 0.01). It was positively correlated with the body mass index (P < 0.05). Multiple regression analysis showed that a small FTA could predict the KVA at IC (ß: 0.52, 95% confidence interval (CI): 2.24-(-0.42); P < 0.01). The maximum KVA during the 40-ms period after IC was associated with the FTA (ß: 0.46, 95% CI: 2.22-(-0.26); P = 0.02) and height (ß: 0.40, 95% CI: 0.59-(-0.02); P = 0.04). CONCLUSION: At 8-10 months after ACL reconstruction, the KVA was significantly correlated with the FTA, with reduced FTA being associated with an increased dynamic KVA during single-leg hop landing. The measurement of anatomical parameters may aid in predicting the second ACL injury risk after reconstruction.

Whole-body vibration enhances effectiveness of "locomotion training" evaluated in healthy young adult women.

[Purpose] Locomotion training is recommended as a countermeasure against locomotive syndrome. Recently, whole-body vibration has been clinically applied in rehabilitation medicine. Therefore, we aimed to investigate the preliminary effectiveness of whole-body vibration on locomotion training. [Participants and Methods] Overall, 28 healthy adult females were randomly assigned to either a locomotion training group using a whole-body vibration device (whole-body vibration group, n=14) or training on the flat floor (non-whole-body vibration group: n=14). Participants conducted two sets of locomotion training twice a day and three times a week for 12 weeks. [Results] A significant difference was observed in the group factor for all outcome measures and in the before and after the training factor for Timed Up and Go test. After the training, knee muscle strength, dynamic balance, and mobility function in the whole-body vibration group were significantly improved compared with the non-whole-body vibration group. In the whole-body vibration group, the Timed Up and Go time after the training was significantly shorter compared with that before training. [Conclusion] The results suggest that locomotion training with whole-body vibration can improve the physical functions in healthy adult females and locomotion training using whole-body vibration might enhance the effectiveness of locomotion training.

The Relationship between Knee Biomechanics and Clinical Assessments in ACl Deficient Patients.

The purpose of this study was to clarify the relationship between knee biomechanics and clinical assessments in ACL deficient patients. Subjects included 22 patients with unilateral ACL rupture and 22 healthy controls. Knee kinematics and kinetics during walking and running were examined using a 3-dimensional motion analysis system. The passive knee joint laxity, range of motion of knee joint, and knee muscle strength were also measured. Correlations between the knee kinematic and kinetic data and clinical assessments were evaluated. In the ACL deficient patients, there were no significant relationships between tibial translation during walking and running and passive knee joint laxity. The correlations between knee kinematics and kinetics and range of motion of knee joint were also not significant. Additionally, there were no significant correlations between knee kinematics during walking and knee muscle strength. However, there were several significant correlations between knee kinematics during running and knee muscle strength. The results demonstrate the importance of knee muscle strength for knee kinematics and kinetics during running in ACL deficient patients. Patients with stronger knee muscle strength may demonstrate more nearly normal knee joint movement during dynamic activities such as running.

Biomechanics of single-leg running using lofstrand crutches in amputee soccer.

[Purpose] Amputee soccer is a game for individuals with amputations. Players use lofstrand crutches to move around the field and kick the ball. Scoring quick goals during a match requires players to have maximum running skills. Notably, a few parameters affect the running speed in players; however, no study has reported the biomechanical analysis of running in amputee soccer. Thus study aimed to analyze the biomechanics of single-leg running using lofstrand crutches in 12 healthy adult males (6 with prior amputee soccer experience and 6 without such experience). [Participants and Methods] The kinematics of the lower limb and the pelvis, the ground reaction force, and skill in using the crutches were evaluated using 3 dimensional motion analysis combined with 8 force plates. Lower leg amputation was simulated in all participants by maintaining the non-dominant knee in a position of maximum flexion using an elastic band. [Results] Significant differences were observed between experienced and non-experienced participants with regard to the angle of the pelvis and the crutch stance phase. Specifically, higher running speed was associated with an increased forward tilt of the pelvis and a shorter crutch stance phase. [Conclusion] These findings will be useful to improve the running speed of amputee soccer players.

Symmetry tensiomyographic neuromuscular response after chronic anterior cruciate ligament (ACL) reconstruction.

PURPOSE: Quadriceps muscle weakness is common following anterior cruciate ligament (ACL) reconstruction. Tensiomyography is a recent method to assess muscle strength, and one that also enables evaluation of individual muscles. The purpose of this study was to evaluate motor unit recruitment and investigate the effects on mechanical and contractile characteristics of the quadriceps and hamstring muscles after chronic ACL reconstruction. METHODS: This study recruited 20 participants: three males and seven females at 24 months after ACL reconstruction, and three males and seven females with no history of knee injury (control group). All participants underwent tensiomyographic assessment of each thigh muscle, bilaterally, to measure maximal displacement, delay time, contraction time, sustained time, and half-relaxation time. The following muscles were evaluated: vastus medialis, vastus lateralis, rectus femoris, semitendinosus, and biceps femoris. Mean normalized muscle peak torque, mean normalized maximum work done, mean angle to peak torque, and mean time to peak torque based on isokinetic peak torque measurements were calculated in both groups. RESULTS: Maximal displacement of the vastus medialis on the ACL reconstruction side was significantly higher than for the non-ACL reconstruction side and for the control group (p = 0.026). Half-relaxation time for the vastus medialis and biceps femoris was significantly higher for both the ACLR and non-ACLR sides compared with the control group (p = 0.001). There were also significant differences in symmetry in the vastus medialis and biceps femoris when comparing results between the ACL reconstruction group and the control group (p = 0.034, p = 0.043, respectively). CONCLUSIONS: The presence of strength and symmetry deficits in the vastus medialis and biceps femoris suggests the need for long-term post-operative training following ACL reconstruction. There are clinical relevant improvements of muscle response and velocity as well as muscle strength in patients with chronic ACLR. LEVEL OF EVIDENCE: II.

The Acute Effects of Static and Cyclic Stretching on Muscle Stiffness and Hardness of Medial Gastrocnemius Muscle.

This study aimed to clarify the acute effects of static stretching (SS) and cyclic stretching (CS) on muscle stiffness and hardness of the medial gastrocnemius muscle (MG) by using ultrasonography, range of motion (ROM) of the ankle joint and ankle plantar flexor. Twenty healthy men participated in this study. Participants were randomly assigned to SS, CS and control conditions. Each session consisted of a standard 5-minute cycle warm-up, accompanied by one of the subsequent conditions in another day: (a) 2 minutes static stretching, (b) 2 minutes cyclic stretching, (c) control. Maximum ankle dorsiflexion range of motion (ROM max) and normalized peak torque (NPT) of ankle plantar flexor were measured in the pre- and post-stretching. To assess muscle stiffness, muscle-tendon junction (MTJ) displacement (the length changes in tendon and muscle) and MTJ angle (the angle made by the tendon of insertion and muscle fascicle) of MG were measured using ultrasonography at an ankle dorsiflexion angle of -10°, 0°, 10° and 20° before and after SS and CS for 2 minutes in the pre- and post-stretching. MG hardness was measured using ultrasound real-time tissue elastography (RTE). The results of this study indicate a significant effect of SS for ROM maximum, MTJ angle (0°, 10°, 20°) and RTE (10°, 20°) compared with CS (p < 0.05). There were no significant differences in MTJ displacement between SS and CS. CS was associated with significantly higher NPT values than SS. This study suggests that SS of 2 minutes' hold duration significantly affected muscle stiffness and hardness compared with CS. In addition, CS may contribute to the elongation of muscle tissue and increased muscle strength.

Risk Vessels of Retropharyngeal Hematoma During Stellate Ganglion Block.

BACKGROUND AND OBJECTIVE: Bleeding into the retropharyngeal space is a potential complication in stellate ganglion block (SGB). Retropharyngeal hematoma formation is considered to be due to damage of small arteries in the region, although only scanty details of the region are available. The aim of this study was to map the risk blood vessels in the retropharyngeal space to avoid accidental damage during SGB. METHODS: Contrast-enhanced 3-dimensional computed tomography images performed on 80 patients were reanalyzed retrospectively to construct detailed map of cervical blood vessels that are prone to damage and bleeding during SGB. RESULTS: Of the 160 bilateral necks, 6 (3.8%) and 82 (51.3%) small arteries were identified in the medial portions of the ventral surface of the transverse processes of the sixth and seventh cervical vertebrae, respectively. In particular, 5 of the 6 small arteries detected in the medial portion of the ventral surface of the transverse process of the sixth cervical vertebra were the inferior thyroid artery (ITA). Of the 160 vertebral arteries, 2 arteries were missing, 4 (2.5%) entered the transverse foramen of the fifth cervical vertebra, whereas 1 artery (0.6%) entered the transverse foramen of the fourth cervical vertebra. CONCLUSIONS: Three-dimensional computed tomography identified the ITA in the medial portion of the ventral surface of the transverse process of the sixth cervical vertebra. The risk vessels of retropharyngeal hematoma during SGB could include the ITA.

Courses of change in knee adduction moment and lateral thrust differ up to 1 year after TKA.

PURPOSE: In total knee arthroplasty (TKA), dynamic knee loading may loosen the artificial joint and bone or cause polyethylene wear after prolonged use. TKA decreases knee adduction moment at 6 months, but this effect is lost by 1 year post-operatively. However, lateral thrust after TKA has not been clarified. We hypothesized that like knee adduction moment, lateral thrust would return to baseline levels by 1 year post-operatively. METHODS: Participants were 15 patients who underwent TKA for medial knee OA. Japanese Orthopaedic Association (JOA) score, numeric rating scale, and gait analysis (measurement of peak knee adduction moment, knee varus angle at peak knee adduction moment, lateral thrust, and gait speed) were performed preoperatively (baseline) and 3 weeks, 3 and 6 months, and 1 year post-operatively. RESULTS: JOA score improved from 55 ± 9.8 to 78 ± 12.1 at 1 year post-operatively, and pain decreased significantly from baseline at each follow-up (p < 0.001). Significant increases in gait speed were observed at 6 months and 1 year (p < 0.001). Peak knee adduction moment during stance phase was significantly lower at 3 weeks, 3 months, and 6 months compared to baseline (p < 0.05), but no significant changes were seen at 1 year. Knee varus at peak knee adduction moment did not differ significantly between any measurement points, while lateral thrust was decreased at 6 months and 1 year compared to baseline (p < 0.05). CONCLUSIONS: Temporal courses of changes up to 1 year after TKA differed between knee adduction moment and lateral thrust, so our hypothesis was rejected. LEVEL OF EVIDENCE: IV.

Posterior tibial displacement in the PCL-deficient knee is reduced compared to the normal knee during gait.

PURPOSE: Most individuals with an isolated posterior cruciate ligament (PCL) injury do not complain of disability even if posterior instability is objectively revealed by a static physical examination, such as the posterior drawer test. This suggests it is insufficient to only evaluate posterior instability under static conditions. Therefore, we have investigated the effect of isolated PCL injury on the detailed kinematics of the knee in a dynamic environment such as during gait. METHODS: Eight unilateral PCL-deficient males and eight healthy control volunteers participated in this study. Isolated PCL injury was diagnosed by clinical examination. Stress X-ray imaging showed an average side-to-side difference of 12.7 ± 3.5 mm. Knee kinematics including anteroposterior tibial displacement were analysed during walking using the point cluster technique. RESULTS: Posterior tibial displacement from initial contact was significantly smaller during 9-22 % of the gait cycle by an average of 0.4 cm in the PCL group, compared to controls. In the PCL-deficient knee, the external rotational angle increased by an average of 3.3° at the loading response during 3-11 % of the gait cycle and the varus angle from initial contact increased by an average of 2.0° during 28-52 % of the gait cycle, compared to controls. CONCLUSIONS: Dynamic changes in the rotation and posterior translation patterns were seen after isolated PCL injury, suggesting the kinematics of PCL-deficient knees might be different to normal knees. These factors may contribute to long-term osteoarthritic change. Consequently, when choosing conservative treatment for PCL injury, these changes should be considered to prevent osteoarthritic change. LEVEL OF EVIDENCE: III.