In vivo segmental vertebral kinematics in patients with degenerative lumbar scoliosis.

PURPOSE: This study aimed to find a standard of the vertebra kinematics during functional weight-bearing activities in degenerative lumbar scoliosis (DLS) patients. METHODS: Fifty-four patients were involved into this study with forty-two in DLS group and twelve in the control group. The three-dimensional (3D) vertebral models from L1 to S1 of each participant were reconstructed by computed tomography (CT). Dual-orthogonal fluoroscopic imaging, along with FluoMotion and Rhinoceros software, was used to record segmental vertebral kinematics during functional weight-bearing activities. The primary and coupled motions of each vertebra were analyzed in patients with DLS. RESULTS: During flexion-extension of the trunk, anteroposterior (AP) translation and craniocaudal (CC) translation at L5-S1 were higher than those at L2-3 (9.3 ± 5.1 mm vs. 6.4 ± 3.5 mm; P < 0.05). The coupled mediolateral (ML) translation at L5-S1 in patients with DLS was approximately three times greater than that in the control group. During left-right bending of the trunk, the coupled ML rotation at L5-S1 was higher in patients with DLS than that in the control group (17.7 ± 10.3° vs. 8.4 ± 4.4°; P < 0.05). The AP and CC translations at L5-S1 were higher than those at L1-2, L2-3, and L3-4. During left-right torsion of the trunk, the AP translation at L5-S1 was higher as compared to other levels. CONCLUSIONS: The greatest coupled translation was observed at L5-S1 in patients with DLS. Coupled AP and ML translations at L5-S1 were higher than those in healthy participants. These data improved the understanding of DLS motion characteristics.

Study on the balance and gait characteristics of subjects with generalized joint hypermobility residing in high-altitude using wearable devices: a cross-sectional study.

PURPOSE: To investigate the characteristics of balance and gait functions in Generalized Joint Hypermobility (GJH) subjects residing in high-altitude areas. METHODS: This study included 61 university students (28 with GJH and 33 healthy controls) all from the high-altitude region of Linzhi, Tibet Autonomous Region. The Riablo™ wearable intelligent rehabilitation assessment and training system was used to assess static balance (with eyes open and closed) and gait function (during flat walking) in both groups. RESULTS: Compared to healthy subjects, GJH subjects exhibited significantly impaired balance, indicated by an increased distance of the center of pressure position from the ideal center of gravity(EO: P = 0.007, EC: P = 0.031) and greater amplitude of center of pressure displacements (EO: P = 0.043, EC: P = 0.032). Gait velocity(P = 0.007), stride length(P = 0.012), and swing stance phase of the gait cycle(P = 0.046) were significantly reduced in GJH subjects compared to healthy subjects. A significant increase in the flat-foot phase of the gait cycle(P = 0.022) was observed in GJH subjects compared to healthy subjects. CONCLUSION: The current study demonstrated that GJH subjects residing in high-altitude areas exhibit impairments in balance and gait, providing a basis for training and prevention strategies tailored for this population. And this study used the wearable intelligent rehabilitation evaluation and training system in high-altitude areas, providing methodological references for scientific research on balance and gait function under non laboratory conditions. TRIAL REGISTRATION: Controlled Trials No.102772023RT133, Registered 13 October 2023.

The effect of marathon running on the lower extremity kinematics and muscle activities during walking and running tasks.

Patellofemoral pain syndrome (PFPS) is a common injury among runners, and it is thought that abnormal lower extremity biomechanics contribute to its development. However, the relationship between biomechanical changes after a marathon and PFPS injury remains limited. This study aims to investigate whether differences in knee and hip kinematics and lower extremity muscle activities exist in recreational runners before and after a marathon. Additionally, it aims to explore the relationship between these biomechanical changes and the development of PFPS injury. 12 recreational runners participated in the study. Kinematics and muscle activities of the lower extremity were recorded during walking (5 km/h) and running (10 km/h) tasks within 24 hours before and within 5 hours after a marathon. After the marathon, there was a significant decrease in peak knee flexion (walking: p = 0.006; running: p = 0.006) and an increase in peak hip internal rotation (walking: p = 0.026; running: p = 0.015) during the stance phase of both walking and running compared to before the marathon. The study demonstrates a decrease in knee flexion and an increase in hip internal rotation during the stance phase of gait tasks after completing a marathon, which may increase the risk of developing PFPS injury.

Anatomic double-bundle transtibial anterior cruciate ligament reconstruction restores graft length changes but leads to larger graft bending angles.

PURPOSE: The purpose of this study was to evaluate the femoral tunnel position using a modified anatomic transtibial (TT) double-bundle anterior cruciate ligament reconstruction (DBACLR) and to investigate the knee kinematics, graft length and graft bending angle following DBACLR. METHODS: Ten patients who underwent DBACLR using the modified TT technique were included in the study. All patients performed a single-legged lunge under a dual fluoroscopic imaging system to assess the 6 degrees of freedom tibiofemoral kinematics. Femoral tunnel position was evaluated via postoperative three-dimensional (3D) computed tomography. The area centroids of anteromedial (AM) and posterolateral (PL) bundles were determined on 3D knee models. The lengths of AM and PL bundles, as well as graft bending angle at the femoral tunnel aperture, were measured by created virtual fibres. RESULTS: The reconstructed knee rotated more externally compared with the contralateral knee between 0° and 60° (p ≤ 0.049). There is no significant difference in the length change of AM bundle (n.s.) and PL bundle (n.s.) between the two sides from 0° to 120° during the lunge motion. The maximum graft bending angle at the femoral tunnel aperture occurred at 0° of knee flexion, with the AM graft bending angle was 72.6° ± 9.0° and the PL graft bending angle was 90.3° ± 9.7°. CONCLUSION: The modified TT technique used in this study could achieve anatomical ACL reconstruction, restoring graft length change patterns compared to contralateral knees. However, residual rotational instability of the reconstructed knee was observed after DBACLR, despite achieving anatomic tunnel placement. Therefore, double-bundle reconstruction may not sufficiently address the persistent rotational instability of the knee. Additionally, larger graft bending angles at the femoral tunnel aperture were found with the modified TT technique. Therefore, further improvement to the TT technique should focus on reducing the graft's curvature while maintaining the anatomical properties of the knee joint. The findings of this study highlight the need for improved surgical techniques to address residual rotational instability and optimise graft curvature. These improvements are crucial for enhancing patient outcomes and long-term joint function following ACL reconstruction. LEVELS OF EVIDENCE: Level II.

Clinical assessments and gait analysis for patients with Trimalleolar fractures in the early postoperative period.

BACKGROUND: Trimalleolar fracture is a common ankle fracture with serious complications and costly healthcare problem. Most studies used clinical assessments to evaluate the functional status of the patients. Although clinical assessments are valid, they are static and subjective. Dynamic, objective and precise evaluations such as gait analysis are needed. Ankle biomechanics studies on gait in patients with trimalleolar fractures are still rare. This study aimed to investigate the clinical outcomes and gait biomechanics in patients with trimalleolar fractures in the early postoperative period and compared to healthy controls. METHODS: This was a cross-sectional study. 12 patients with trimalleolar fractures were recruited, and 12 healthy people served as controls. All patients underwent clinical assessments: Olerud and Molander ankle score (OMAS), ankle swelling and passive range of motion (ROM) of ankle, and completed gait biomechanical analysis when weight-bearing was allowed: temporal-spatial parameters, plantar pressure distributions, and surface electromyography (sEMG). The control group only performed gait test. RESULTS: Patients had poor outcomes of clinical assessments in the short-term. During gait analysis, patients presented compromised gait patterns: shorter step length, larger step width, slower walking speed and shorter single support compared to healthy controls (P < 0.001), and patients showed asymmetrical gait. Symmetry index of step width and walking speed were mainly correlated with the difference of ankle inversion ROM between two sides (R = -0.750, P = 0.005; R = -0.700, P = 0.011). During walking, patients showed abnormal dynamic plantar pressure features (mainly in the hindfoot and forefoot regions), and the IEMG (integrated electromyography) of tibial anterior muscle (TA) and peroneal longus muscle (PL) were larger than healthy controls (P = 0.002, 0.050). CONCLUSIONS: Patients with trimalleolar fractures showed physical impairments of the ankle, and presented altered gait parameters compared to healthy subjects in the short-term. The ankle stability of patients declined, and deficits in TA and PL muscle ability might contribute to it. Restoring complete muscle functions and improving passive ankle ROM are significant to promote the recovery of a normal gait pattern.

Differences in patellofemoral kinematics between weightbearing and non-weightbearing conditions in patients with arthrofibrosis after anterior cruciate ligament reconstruction.

OBJECTIVE: The purpose of this study is to evaluate the difference of patellofemoral kinematics between weightbearing and non-weightbearing conditions in the arthrofibrotic knee after anterior cruciate ligament (ACL) reconstruction. METHODS: Twenty patients with arthrofibrosis after ACL reconstruction were included in the study. Computed tomography scanner and dual fluoroscopic imaging techniques were used to compare patellofemoral kinematics of the affected knee between weightbearing knee flexion and non-weightbearing knee flexion. In both positions, patellofemoral kinematics in six degrees-of-freedom (6 DOF) were measured respectively. RESULTS: The patellar lateral tilt angle (p = 0.007) and medial patellar translation (p = 0.043) under the weightbearing condition were significantly decreased compared to the non-weightbearing task between 5° and 15° of knee flexion. The lateral patellar translation during a non-weightbearing task was significantly decreased between 60° and 75° of knee flexion (p = 0.005), and the inferior patellar translation under the weightbearing condition was significantly increased between 45° and 75° of knee flexion (p = 0.040). CONCLUSION: These results indicate that patellofemoral kinematics during non-weightbearing positions do not sufficiently represent the patellar tracking during functional weightbearing activities. Our findings of this study establish the clinical relevance and significance of assessing the patellofemoral kinematics under the weightbearing condition when evaluating patients with arthrofibrosis after ACL reconstruction. TRIAL REGISTRATION: Trial registration number: ChiCTR1900025977.

Test-Retest Reliability of a New Device Versus a Long-Arm Goniometer to Evaluate Knee Proprioception.

CONTEXT: Many methods used to evaluate knee proprioception have shortcomings that limit their use in clinical settings. Based on an inexpensive 3D camera, a new portable device was recently used to evaluate the joint position sense (JPS) of the knee joint. However, the test-retest reliability of the new method remains unclear. This study aimed to evaluate the test-retest reliability of the new device and a long-arm goniometer for assessing knee JPS, and to compare the variability of the 2 methods. DESIGN: Prospective observational study of the test-retest reliability of knee JPS measurements. METHODS: Twenty-one healthy adults were tested in 2 sessions with a 1-week interval. Three target knee flexion angles (30°, 45°, and 60°) were reproduced in each session. Target and reproduced angles were measured with both methods. Intraclass correlation coefficients, standard error of the measurement, and Bland-Altman plots were used to quantify test-retest reliability. Paired t tests were used to compare knee JPS (absolute error of the target-reproduced angle) between the methods. RESULTS: The new device (good to excellent intraclass correlation coefficients .74-.80; standard error of the measurement 0.52°-0.61°) demonstrated better test-retest reliability than the goniometer (poor to fair intraclass correlation coefficients .23-.43; standard error of the measurement 0.89°-2.07°) and better test-retest agreement (respective mean differences for the 30°, 45°, and 60° knee angles: 0.11°, 0.13°, and 0.41° for the new system; 0.84°, 1.52°, and 1.18° for the goniometer). The measurements (absolute errors of the target-reproduced angles) with the goniometer were significantly greater than those with the new device (P < .05); the SDs of repeated measurements with the goniometer (1.50°-2.41°) were greater than with the new device (1.08°-1.38°). CONCLUSIONS: Given that the new device has good reliability and sufficient precision, it is the better alternative for evaluating knee JPS. Goniometers should be used with caution to assess knee JPS.

Change in Susceptibility Values in Knee Cartilage After Marathon Running Measured Using Quantitative Susceptibility Mapping.

BACKGROUND: Quantitative susceptibility mapping (QSM) has been used to study the magnetic susceptibility properties of collagen fibers in articular cartilage; however, it is unclear whether QSM is sensitive to changes due to degradation caused by long-distance running. It is clinically important to understand the link between long-distance running and microstructural changes in knee cartilage. PURPOSE: To investigate the ability of QSM to assess microstructural changes within cartilage after repetitive loading. STUDY TYPE: Prospective. POPULATION: Thirteen recreational, male long-distance runners. FIELD STRENGTH/SEQUENCE: Three-dimensional gradient recalled echo acquired at 3 T. ASSESSMENT: Magnetic resonance imaging (MRI) and 3D kinematics (translations and rotations during treadmill walking and running) of the knee joint were collected before and after marathon running. The compartments for analysis included the patella, trochlea, and subregions of femoral and tibial cartilage. Changes in regional susceptibility and cartilage thickness were calculated after marathon running. A susceptibility profile was obtained by fitting susceptibility as a function of the normalized depth of cartilage from the superficial to deep layers. STATISTICAL TESTS: Paired t-test or Wilcoxon signed-rank test, 95% confidence interval (CI) of the depth-wise susceptibility profile, Pearson correlation or Spearman correlation. RESULTS: There was a statistically significant increase in susceptibility value in the weight-bearing region of central medial femoral cartilage (cMF-c) after marathon running (pre-marathon: -0.0219 ± 0.0151 ppm, post-marathon: -0.0070 ± 0.0213 ppm, P < 0.05), while the cartilage thickness did not show significant changes in any regions (P-value range: 0.068-0.963). Significant susceptibility elevations occurred in the middle and deep layers of cMF-c (95% CIs did not overlap). A trend toward a positive correlation was found between the changes in susceptibility value in cMF-c and proximal-distal translation of the knee joint during walking (r = 0.55, P = 0.101) and running (r = 0.57, P = 0.089). DATA CONCLUSION: Localized magnetic susceptibility alterations were observed within knee cartilage in the weight-bearing area after repetitive loading without any morphologic changes. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 2.

Knee Extensor Mechanism Strength and Its Relationship to Patellofemoral Kinematics in Individuals With Arthrofibrosis Within 6 Months After Anterior Cruciate Ligament Reconstruction.

CONTEXT: Performance in strength and assessment of patellar tracking is important for patients with arthrofibrosis after anterior cruciate ligament (ACL) reconstruction. OBJECTIVE: The study was to examine the difference of patellofemoral kinematics between the affected and the contralateral limb and to evaluate the relationship between knee extensor strength and patellofemoral kinematics in patients with arthrofibrosis after ACL reconstruction. DESIGN: Cohort study (diagnosis); level of evidence, 3. SETTING: Laboratory. PATIENTS: A prospective cohort of 20 patients with arthrofibrosis after ACL reconstruction was recruited. INTERVENTIONS: A total of 20 patients who underwent arthroscopic reconstruction of the double-bundle ACL with a hamstring tendon autograft received standardized patellofemoral kinematics testing and knee extensor strength testing within 6 months after primary ACL reconstruction. Computed tomography and dual fluoroscopic imaging were used to evaluate in vivo patellofemoral kinematics of affected and contralateral knees during a lunge task. Knee extensor mechanism strength was measured using a handheld dynamometer. MAIN OUTCOME MEASURES: A limb symmetry index of knee strength and patellar mobility was calculated and satisfactory performance defined as ≥90%. RESULTS: There was a statistically significant decrease in the range of patellar inferior shift (P = .020; d = 0.81), flexion (P = .026; d = 0.95), lateral tilt (P = .001; d = 1.04), and lateral rotation (P < .001; d = 0.89) in the affected knee compared with the contralateral knee from 15° to 75° of knee flexion. There was a strong positive linear correlation between knee extensor strength and patellar inferior shift (r = .747; P = .008). A knee extensor strength limb symmetry index <90% was 89% sensitive and 9% specific for limited patellar inferior shift. CONCLUSIONS: Patients with arthrofibrosis after ACL reconstruction presented decreased patellar mobility in the arthrofibrotic knee compared with the contralateral knee. The strong correlation between knee extensor strength and patellar inferior shift of the arthrofibrotic knee demonstrates the importance of knee extensor strength in the diagnosis and treatment of patients with knee arthrofibrosis. The knee extensor mechanism strength has high sensitivity but low specificity in identifying a decrease in patellar inferior shift in patients with arthrofibrosis after ACL reconstruction.

Prediction of in vivo knee joint kinematics using a combined dual fluoroscopy imaging and statistical shape modeling technique.

Using computed tomography (CT) or magnetic resonance (MR) images to construct 3D knee models has been widely used in biomedical engineering research. Statistical shape modeling (SSM) method is an alternative way to provide a fast, cost-efficient, and subject-specific knee modeling technique. This study was aimed to evaluate the feasibility of using a combined dual-fluoroscopic imaging system (DFIS) and SSM method to investigate in vivo knee kinematics. Three subjects were studied during a treadmill walking. The data were compared with the kinematics obtained using a CT-based modeling technique. Geometric root-mean-square (RMS) errors between the knee models constructed using the SSM and CT-based modeling techniques were 1.16 mm and 1.40 mm for the femur and tibia, respectively. For the kinematics of the knee during the treadmill gait, the SSM model can predict the knee kinematics with RMS errors within 3.3 deg for rotation and within 2.4 mm for translation throughout the stance phase of the gait cycle compared with those obtained using the CT-based knee models. The data indicated that the combined DFIS and SSM technique could be used for quick evaluation of knee joint kinematics.

Dynamic motion characteristics of the lower lumbar spine: implication to lumbar pathology and surgical treatment.

PURPOSE: Many studies have reported on the segmental motion range of the lumbar spine using various in vitro and in vivo experimental designs. However, the in vivo weightbearing dynamic motion characteristics of the L4-5 and L5-S1 motion segments are still not clearly described in literature. This study investigated in vivo motion of the lumbar spine during a weight-lifting activity. METHODS: Ten asymptomatic subjects (M/F: 5/5; age: 40-60 years) were recruited. The lumbar segment of each subject was MRI-scanned to construct 3D models of the L2-S1 vertebrae. The lumbar spine was then imaged using a dual fluoroscopic imaging system as the subject performed a weight-lifting activity from a lumbar flexion position (45°) to maximal extension position. The 3D vertebral models and the fluoroscopic images were used to reproduce the in vivo vertebral positions along the motion path. The relative translations and rotations of each motion segment were analyzed. RESULTS: All vertebral motion segments, L2-3, L3-4, L4-5 and L5-S1, rotated similarly during the lifting motion. L4-5 showed the largest anterior-posterior (AP) translation with 2.9 ± 1.5 mm and was significantly larger than L5-S1 (p < 0.05). L5-S1 showed the largest proximal-distal (PD) translation with 2.8 ± 0.9 mm and was significantly larger than all other motion segments (p < 0.05). CONCLUSIONS: The lower lumbar motion segments L4-5 and L5-S1 showed larger AP and PD translations, respectively, than the higher vertebral motion segments during the weight-lifting motion. The data provide insight into the physiological motion characteristics of the lumbar spine and potential mechanical mechanisms of lumbar disease development.

[Application of digital orthopedic technology for observing degenerative lumbar segmental instability of three-dimensional kinematic characteristics in vivo].

OBJECTIVE: To explore the characteristics of three-dimensional motion of lumbar instability segmental in vivo under physiological weight bearing so as to establish three-dimensional diagnostic criteria for degenerative lumbar segmental instability (DLSI). METHODS: Eight patients aged 29-65 years with DLSI at L3/4 were studied as instability group (L3/4), 9 patients aged 51-60 years with DLSI at L4/5 as instability group (L4/5) and 10 healthy volunteers aged 26-51 years as normal group. Three-dimension (3D) reproductions by matching lumbar spine models were reconstructed from thin-section computed tomography scans. Spine motions were then reproduced by matching lumber spine models and images from dual fluoroscopic imaging system (DFIS). The models were matched to the osseous outlines of images from two orthogonal views to determine the SD position of vertebrae for each pose. From local coordinate systems at end plates, the motion of cephalad vertebrae relative to cauddal vertebrae was calculated for vertebrae levels. RESULTS: The motion pattern at L3/4 was altered . During flexion-extension, migration was significantly larger than normal group along sagittal axis (P < 0.05); rotation was significantly larger than normal group along vertical axis; migration was significantly smaller than normal group along vertical axis; during left-right twisting, rotation was significantly larger than normal group along vertical axis (P < 0.05). The motion pattern at L4/5 was also altered . During flexion-extension, migrations was significantly larger than normal group along sagittal axis (P < 0.05). During left-right twisting, migration and rotation were significantly smaller than normal group along vertical axis (P < 0.05). Rotation was significantly larger than normal group along sagittal axis. During left-right bending, rotation was significantly larger than normal group along sagittal axis (P < 0.05). CONCLUSION: Lumbar instability segments were significantly different compared with normal lumbar segments. And lumbar instability segments (at L3/4) were also different from lumbar instability segments (at L4/5). Different three-dimensional diagnostic criteria should be formulated for different lumbar instability segments.

Anatomic femoral tunnel and satisfactory clinical outcomes achieved with the modified transtibial technique in anterior cruciate ligament reconstruction: A systematic review and meta-analysis.

Background: Anatomic anterior cruciate ligament (ACL) reconstruction is considered the gold standard treatment for ACL injuries because it aims to restore the knee's normal anatomy and stability, while also protecting long-term knee health. Long-term clinical and radiological outcomes after ACL reconstruction using the modified TT technique are unclear. Objective: To assess the clinical and radiological outcomes following ACL reconstruction using modified transtibial (TT) techniques at a minimum 12-month follow-up. Design: A systematic review with meta-analysis. Methods: PubMed, EMBASE, Web of Science, the Cochrane Library, and MEDLINE databases were searched from the inception to December 1, 2022. PICO search strategy was used to identify studies applying modified TT techniques on patients with ACL reconstruction and a minimum follow-up of 12 months. Eligible studies were identified independently by two reviewers. We extracted data on patient demographics, surgical characteristics, patient reported outcomes including subjective evaluations and clinical outcomes. Radiological data including femoral and tibial tunnel position, femoral and tibial tunnel length, and femoral tunnel angle were also extracted. The tunnel position was evaluated using the quadrant method based on three-dimensional computed tomography (3D CT) images. The standardized mean difference (SMD) and 95 % confidence interval (CI) were calculated for clinical and radiological outcomes. Results: Sixteen studies involving 628 patients were finally included. The SMD of Lysholm (90.39; 95 % CI 83.41-97.38), IKDC (86.07; 95 % CI 79.84-92.31), and Tegner (6.15; 95 % CI 3.96-8.33) scores were considered satisfactory. The depth of the femoral tunnel showed a pooled SMD of 30.08 % (95 % CI 28.25-31.91 %), and the height showed a pooled SMD of 37.72 % (95 % CI 35.75-39.70 %). The pooled SMD for the femoral tunnel angle in the coronal plane was 48.27°(95 % CI 43.14-53.40°), and the pooled SMD for the femoral tunnel length was 33.98 mm (95 % CI 29.03-38.93 mm). Conclusions: This investigation has shown that modified TT technique can create an anatomic femoral tunnel and maintain optimal tunnel length and angulation. Most patients had satisfactory subjective outcomes and physical examinations after ACL reconstruction using modified TT technique. This information may assist in guiding expectations of clinicians and patients following ACL reconstruction with modified TT technique.

Effects of added trunk load on the in vivo kinematics of talocrural and subtalar joints during landing.

BACKGROUND: Landing from heights is a common movement for active-duty military personnel during training. And the additional load they carry while performing these tasks can affect the kinetics and ankle kinematic of the landing. Traditional motion capture techniques are limited in accurately capturing the in vivo kinematics of the talus. This study aims to investigate the effect of additional trunk load on the kinematics of the talocrural and subtalar joints during landing, using a dual fluoroscopic imaging system (DFIS). METHODS: Fourteen healthy male participants were recruited. Magnetic resonance imaging was performed on the right ankle of each participant to create three-dimensional (3D) models of the talus, tibia, and calcaneus. High-speed DFIS was used to capture the images of participants performing single-leg landing jumps from a height of 40 cm. A weighted vest was used to apply additional load, with a weight of 16 kg. Fluoroscopic images were acquired with or without additional loading condition. Kinematic data were obtained by importing the DFIS data and the 3D models in virtual environment software for 2D-3D registration. The kinematics and kinetics were compared between with or without additional loading conditions. RESULTS: During added trunk loading condition, the medial-lateral translation range of motion (ROM) at the talocrural joint significantly increased (p < 0.05). The subtalar joint showed more extension at 44-56 ms (p < 0.05) after contact. The subtalar joint was more eversion at 40-48 ms (p < 0.05) after contact under the added trunk load condition. The peak vertical ground reaction force (vGRF) significantly increased (p < 0.05). CONCLUSIONS: With the added trunk load, there is a significant increase in peak vGRF during landing. The medial-lateral translation ROM of the talocrural joint increases. And the kinematics of the subtalar joint are affected. The observed biomechanical changes may be associated with the high incidence of stress fractures in training with added load.

Acute effect of foot strike patterns on in vivo tibiotalar and subtalar joint kinematics during barefoot running.

BACKGROUND: Foot kinematics, such as excessive eversion and malalignment of the hindfoot, are believed to be associated with running-related injuries. The majority of studies to date show that different foot strike patterns influence these specific foot and ankle kinematics. However, technical deficiencies in traditional motion capture approaches limit knowledge of in vivo joint kinematics with respect to rearfoot and forefoot strike patterns (RFS and FFS, respectively). This study uses a high-speed dual fluoroscopic imaging system (DFIS) to determine the effects of different foot strike patterns on 3D in vivo tibiotalar and subtalar joints kinematics. METHODS: Fifteen healthy male recreational runners underwent foot computed tomography scanning for the construction of 3-dimensional models. A high-speed DFIS (100 Hz) was used to collect 6 degrees of freedom kinematics for participants' tibiotalar and subtalar joints when they adopted RFS and FFS in barefoot condition. RESULTS: Compared with RFS, FFS exhibited greater internal rotation at 0%-20% of the stance phase in the tibiotalar joint. The peak internal rotation angle of the tibiotalar joint under FFS was greater than under RFS (p < 0.001, Cohen's d = 0.92). RFS showed more dorsiflexion at 0%-20% of the stance phase in the tibiotalar joint than FFS. RFS also presented a larger anterior translation (p < 0.001, Cohen's d = 1.28) in the subtalar joint at initial contact than FFS. CONCLUSION: Running with acute barefoot FFS increases the internal rotation of the tibiotalar joint in the early stance. The use of high-speed DFIS to quantify the movement of the tibiotalar and subtalar joint was critical to revealing the effects of RFS and FFS during running.

The effect of knee braces on knee joint kinematics at different exercise speeds.

This study aims to investigate the influence of a new semi-rigid knee joint braces on kinematics using the Opti-knee knee joint kinematic analysis system at various exercise speeds. Twenty-four healthy young male adults were recruited for this study. Participants were randomly assessed while wearing and not wearing knee brace at four different speeds on a treadmill: normal walking (3.6 km/h), brisk walking (5.4 km/h), jogging (9 km/h), and moderate intensity running (10.8 km/h). Six degrees of freedom kinematic data from the knee joint were collected. Paired t-tests were conducted to calculate the kinematic differences. At speeds of 3.6 km/h and 5.4 km/h, wearing the knee brace led to reduced knee joint mobility in anterior-posterior translation, superior-inferior translation, internal-external rotation, and flexion-extension angles during the stance phase (P < 0.05). At 9 km/h, wearing the brace reduced knee joint internal-external rotation and flexion-extension mobility during the stance phase (P < 0.05). At 10.8 km/h, wearing the brace reduced knee joint flexion-extension mobility during the stance phase (P < 0.05). Wearing brace has significant influence on knee kinematics at four speeds, and the effect of brace varies with the speed of movement.

Optimal tibial tunnel angulation for anatomical anterior cruciate ligament reconstruction using transtibial technique.

Numerous studies have suggested that the primary cause of failure in transtibial anterior cruciate ligament reconstruction (ACLR) is often attributed to non-anatomical placement of the bone tunnels, typically resulting from improper tibial guidance. We aimed to establish the optimal tibial tunnel angle for anatomical ACLR by adapting the transtibial (TT) technique. Additionally, we aimed to assess graft bending angle (GBA) and length changes during in vivo dynamic flexion of the knee. Twenty knee joints underwent a CT scan and dual fluoroscopic imaging system (DFIS) to reproduce relative knee position during dynamic flexion. For the single-legged lunge, subjects began in a natural standing position and flexed the right knee beyond 90° When performing the lunge task, the subject supported the body weight on the right leg, while the left leg was used to keep the balance. The tibial and femoral tunnels were established on each knee using a modified TT technique for single-bundle ACLR. The tibial tunnel angulation to the tibial axis and the sagittal plane were measured. Considering that ACL injuries tend to occur at low knee flexion angles, GBA and graft length were measured between 0° and 90° of flexion in this study. The tibial tunnel angulated the sagittal plane at 42.8° ± 3.4°, and angulated the tibial axis at 45.3° ± 5.1° The GBA was 0° at 90° flexion of the knee and increased substantially to 76.4 ± 5.5° at 0° flexion. The GBA significantly increased with the knee extending from 90° to 0° (p < 0.001). The ACL length was 30.2mm±3.0 mm at 0° flexion and decreased to 27.5mm ± 2.8 mm at 90° flexion (p = 0.072). To achieve anatomic single-bundle ACLR, the optimal tibial tunnel should be angulated at approximately 43° to the sagittal plane and approximately 45° to the tibial axis using the modified TT technique. What's more, anatomical TT ACLR resulted in comparable GBA and a relatively constant ACL length from 0° to 90° of flexion. These findings provide theoretical support for the clinical application and the promotion of the current modified TT technique with the assistance of a robot to achieve anatomical ACLR.

An in Vivo, Three-Dimensional (3D), Functional Centers of Rotation of the Healthy Cervical Spine.

OBJECTIVE: This study examined cervical center of rotation (COR) positions in 7 postures using validated cone beam computed tomography (CBCT) combined with 3D-3D registration in healthy volunteers. METHODS: CBCT scans were performed on 20 healthy volunteers in 7 functional positions, constructing a three-dimensional (3D) model. Images were registered to the neutral position using 3D-3D registration, allowing analysis of kinematic differences and rotational axes. COR measurements were obtained for each segment (C2/3 to C6/7) in each posture. RESULTS: The CORs of C2/3 to C6/7 were predominantly posterior (-5.3 ± 3.8 ∼ -0.6 ± 1.2 mm) and superior (16.5 ± 6.0 ∼ 23.6 ± 3.2 mm) to the intervertebral disc's geometric center (GC) in flexion and extension. However, the C4/5 segment's COR was anterior to the GC (2.0 ± 9.8 mm) during flexion and close to it in the right-left direction. During left-right twisting, the CORs of C2/3-C6/7 were posterior (-21.8 ± 10.5 ∼-0.9 ± 0.8 mm) and superior (3.1 ± 7.5 ∼23.2 ± 3.6 mm) to the GCs in anterior-posterior and superior-inferior directions, without consistent right-left directionality. During left-right bending, each segment's COR was predominantly posterior (-25.2 ± 13.1 ∼-6.5 ± 9.9 mm) and superior (0.3 ± 12.5 ∼12.1 ± 5.1 mm) to the GC in anterior-posterior and superior-inferior directions, except for the C2/3 segment, located inferiorly (-5.9 ± 4.1 mm) in left bending. The right-left COR position varied across segments. CONCLUSIONS: Our findings reveal segment-specific and posture-dependent COR variations. Notably, the CORs of C3/4, C4/5, and C5/6 consistently align near the intervertebral disc's GC at different postures, supporting their suitability for total disc replacement surgery within the C3/4 to C5/6 segments.

Robotic-assisted anatomic anterior cruciate ligament reconstruction: a comparative analysis of modified transtibial and anteromedial portal techniques in cadaveric knees.

Introduction: This study employed surgical robot to perform anatomic single-bundle reconstruction using the modified transtibial (TT) technique and anteromedial (AM) portal technique. The purpose was to directly compare tunnel and graft characteristics of the two techniques. Methods: Eight cadaveric knees without ligament injury were used in the study. The modified TT and AM portal technique were both conducted under surgical robotic system. Postoperative data acquisition of the tunnel and graft characteristics included tibial tunnel position, tunnel angle, tunnel length and femoral tunnel-graft angle. Results: The mean tibial tunnel length of the modified TT technique was significantly shorter than in the AM portal technique (p < 0.001). The mean length of the femoral tunnel was significantly longer for the modified TT technique than for the AM portal technique (p < 0.001). The mean coronal angle of the tibial tunnel was significantly lower for the modified TT technique than for the AM portal technique (p < 0.001). The mean coronal angle of the femoral tunnel was significantly lower for the AM portal technique than for the modified TT technique (p < 0.001). The AM portal technique resulted in a graft bending angle that was significantly more angulated in the coronal (p < 0.001) and the sagittal planes (p < 0.001) compared with the modified TT technique. Discussion: Comparison of the preoperative planning and postoperative femoral tunnel positions showed that the mean difference of the tunnel position was 1.8 ± 0.4 mm. It suggested that the surgical navigation robot could make predictable tunnel position with high accuracy. The findings may support that the modified TT technique has benefits on femoral tunnel length and obliquity compared with AM portal technique. The modified TT technique showed a larger femoral tunnel angle in the coronal plane than the AM portal technique. Compared with the modified TT technique, the more horizontal trajectory of the femoral tunnel in the AM portal technique creates a shorter femoral tunnel length and a more acute graft bending angle.

Discussion on Efficacy of intensive acupuncture versus sham acupuncture in knee osteoarthritis: a randomized controlled trial published in Arthritis & Rheumatology. / 对Arthritis & Rheumatology"å¼ºåŒ–é’ˆåˆºå¯¹æ¯”å‡é’ˆæ²»ç–—è†éª¨å ³èŠ‚ç‚Žéšæœºå¯¹ç §è¯•éªŒ"一文的讨论.

Professor LIU Cunzhi's team from Beijing University of Chinese Medicine published Efficacy of intensive acupuncture versus sham acupuncture in knee osteoarthritis: a randomized controlled trial in Arthritis & Rheumatology on November 10th, 2021, which demonstrates that three-session per week acupuncture is safe and effective for knee osteoarthritis patients. Experts from home and abroad discussed in depth the study design, acupuncture protocol, and interpretation of the results of the trial, emphasizing the importance of pretrial implementation, acupuncture dosage, reasonable setting of control group and assessing the efficacy of acupuncture, and pointed out that the mechanism of acupuncture for knee osteoarthritis still needs further study, and how to promote acupuncture for knee osteoarthritis according to the clinical practice abroad while ensuring the efficacy of acupuncture is worthwhile to explore.