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The article discusses the case of a Labrador Retriever dog which presented with left pelvic limb monoparesis with excessive external hip rotation. Topics discussed include the anatomic and etiologic diagnoses, the results of thoracic radiography and magnetic resonance imaging, and the presumptive diagnosis of nerve sheath neoplasm.

Background: Knee Osteoarthritis (OA) is a highly prevalent age-related disease. The altered kinematic pattern of the knee joint as well as the adjacent joints affects to progression of knee OA. However, there is a lack of research on how asymmetry of the hip rotation angle affects the gait pattern in knee OA patients. Research question: What are the impacts of asymmetric hip rotation range on gait biomechanical characteristics and do the gait patterns differ between patients with knee OA and healthy elderly people? Methods: Twenty-nine female patients with knee OA and 15 healthy female elders as control group were enrolled in this study. The spatiotemporal parameters, kinematic and kinetic data during walking were measured using a three-dimensional motion capture system. The differences between knee OA and control group were analyzed using an independent t-test. Results: The knee OA group exhibited a significant reduction in hip internal rotation range and internal/external rotation ratio on more affected side (p < 0.05). Significant differences were found in spatiotemporal parameters except to the step width. Significant reductions were also found in kinematic parameters (pelvic lateral tilt range, sagittal angle ranges in hip, knee and ankle, knee adduction mean angle). There were also significant differences in vertical ground reaction force and knee adduction moment (p < 0.05). Conclusions: Knee OA patients have asymmetric hip rotation ranges. Especially limited hip internal rotation could lead to the reduction of pelvic lateral tilt, which may cause greater knee joint loading. Therefore, it is necessary to pay attention to recovery of hip rotation after knee surgery. [ABSTRACT FROM AUTHOR]

Femoral derotation osteotomy is treatment of choice in intoeing gait secondary to cerebral palsy (CP). The aim of this study was to critically appraise the literature regarding the long-term outcomes of femoral derotation surgery in CP. Electronic databases of PubMed and Scopus was used for the literature review by two researchers independently (SB, SC). The study population included patients of cerebral palsy undergoing femoral derotation surgery. The keywords used were "cerebral palsy", "intoeing gait", "femur anteversion", "hip anteversion", "femur derotation" and "femur osteotomy". Nine studies which included 657 limbs in 407 patients were selected for this study of which eight were retrospective in nature. The improvement in hip rotation at stance at last follow up (more than five years) maintained a statistical significance (SMD 1.67 95 %CI 1.12–2.22). Similar statistically significant outcomes were noted for foot progression angle (SMD 1.19 95 %CI 0.92–1.47), anteversion (SMD 2.75 95 %CI 1.49–4.01) and total passive internal rotation (SMD 1.71 95 %CI 1.19–2.22). Femoral derotation surgery is the procedure of choice for correction of intoeing gait in CP. Even though, there is deterioration of results on long-term as compared to short term, majority of the patients shall maintain overall correction without recurrence of an intoeing gait. Future studies with uniform criteria for defining recurrence on the basis of functional limitations shall provide better idea about the natural course of this procedure. • Femoral derotation is the procedure of choice for correcting intoeing gait in CP. • There is overall correction without recurrence of an intoeing gait. • Mid-point of passive hip rotation guides towards amount of correction required. [ABSTRACT FROM AUTHOR]

Abstract Background Knee Osteoarthritis (OA) is a highly prevalent age-related disease. The altered kinematic pattern of the knee joint as well as the adjacent joints affects to progression of knee OA. However, there is a lack of research on how asymmetry of the hip rotation angle affects the gait pattern in knee OA patients. Research question What are the impacts of asymmetric hip rotation range on gait biomechanical characteristics and do the gait patterns differ between patients with knee OA and healthy elderly people? Methods Twenty-nine female patients with knee OA and 15 healthy female elders as control group were enrolled in this study. The spatiotemporal parameters, kinematic and kinetic data during walking were measured using a three-dimensional motion capture system. The differences between knee OA and control group were analyzed using an independent t-test. Results The knee OA group exhibited a significant reduction in hip internal rotation range and internal/external rotation ratio on more affected side (p

Patients with cerebral palsy and increased femoral anteversion frequently show disturbing internal rotation gait which may be treated via femoral derotation osteotomy (FDO). A recent study monitored that hip rotation in gait may heavily depend on the procedure by which it is being determined. Traditional measures using the femoral epicondyles as reference for the knee axis (CONV) resulted in more severe transverse plane deviations compared to those using a functional method (FUNC) with relevant implications for treatment indication of FDO. Is mean hip rotation in stance (mHipRotSt) as obtained via FUNC the more sensitive measure for explaining functional changes after FDO compared to CONV method taking the femoral epicondyles as reference for the knee axis? 3D-gait analysis before and one year after FDO was performed in fourteen patients including functional joint axis determination of the knee of which MR imaging was available in eight patients both pre- and postoperatively. Transverse plane gait parameters were calculated using both approaches (CONV, FUNC). Differences between examinations as well as between methods were determined. Changes in femoral anteversion as measured by MR reasonably well confirm the structural changes as measured clinically and intraoperatively. The average change in mHipRotSt across the group was substantially smaller than the structural change implies. Further, using the FUNC approach led to much smaller values compared to when using the CONV approach. We address this to a mismatch between the axes determined in each method. In the presence of femoral deformity, the knee joint axis as determined via a functional method together with the conventional method (femoral epicondyles for the knee axis) allows to quantify knee rotation independent of torsional parameters of the tibia. It may therefore help to better quantify rotational malalignments in gait and improve decision making of FDO. • Gait and MRI before and after femoral derotation osteotomy is monitored in CP. • Conventional and functional method was applied for knee axis determination. • Structural changes measured clinically match surgery reports and findings with MRI. • Hip rotation largely differed between methods for knee axis determination. • The functional approach complements the conventional for quantifying knee rotation. [ABSTRACT FROM AUTHOR]

Objective Due to the substantial prevalence of patellofemoral pain syndrome and the importance of quadriceps strengthening in knee rehabilitation, determining the best way to activate and strengthen the patella stabilizing muscles is considered as one of important keys of treatment. The aim of this study is to evaluate the effect of different hip rotations associated with ankle dorsiflexion during maximal straight leg raising (SLR) maneuver in the sitting position on thickness and fibers angle of vastus medialis oblique (VMO) and vastus lateralis (VL) muscles using ultrasonography. Materials & Methods This quasi-experimental study was performed on 40 individuals (healthy group: 20, patellofemoral pain syndrome [PFPS] group: 20). VMO and VL thickness and fiber angle were measured using ultrasonography during maximal SLR in 6 positions: hip internal, hip external, and neutral rotations with and without ankle dorsiflexion. Results In between-group comparison, no significant difference was found for all variables with different SLR maneuvers (P>0.05). In the within-group comparison, hip external rotation compared to other hip positions without ankle dorsiflexion resulted in a significant increase in VMO thickness and fiber angle in both groups (P

Objective Due to the substantial prevalence of patellofemoral pain syndrome and the importance of quadriceps strengthening in knee rehabilitation, determining the best way to activate and strengthen the patella stabilizing muscles is considered as one of important keys of treatment. The aim of this study is to evaluate the effect of different hip rotations associated with ankle dorsiflexion during maximal straight leg raising (SLR) maneuver in the sitting position on thickness and fibers angle of vastus medialis oblique (VMO) and vastus lateralis (VL) muscles using ultrasonography. Materials & Methods This quasi-experimental study was performed on 40 individuals (healthy group: 20, patellofemoral pain syndrome [PFPS] group: 20). VMO and VL thickness and fiber angle were measured using ultrasonography during maximal SLR in 6 positions: hip internal, hip external, and neutral rotations with and without ankle dorsiflexion. Results In between-group comparison, no significant difference was found for all variables with different SLR maneuvers (P>0.05). In the within-group comparison, hip external rotation compared to other hip positions without ankle dorsiflexion resulted in a significant increase in VMO thickness and fiber angle in both groups (P<0.05). Also, adding ankle dorsiflexion to different hip rotations during SLR significantly increased the thickness and fiber angle of VMO and VL. Conclusion By changing hip rotations with or without ankle dorsiflexion during SLR, the trend of changes in VMO and VL thickness and fiber angle in the two groups followed the same pattern. Moreover, performing SLR in hip external rotation with ankle dorsiflexion can be recommendable for the rehabilitation of PFPS. [ABSTRACT FROM AUTHOR]

The determination of the knee joint axis (KJA) via specific calibration movements has become a promising alternative to the conventional approach to determine this axis based on regression equations or directly via marker placement on bony landmarks of the knee. Since the orientation of the KJA may differ between methods, it has direct influence on hip rotation and may therefore influence clinical decision making in context of transverse plane gait deviations. Research question: Does a functional KJA calibration lead to clinically relevant differences in hip rotation estimates during gait compared to the conventional method? 95 subjects (age: 19.9 years; BMI: 21.1 kg/m2), including 71 patients with potential rotation malalignment, were prospectively examined and underwent 3D gait analysis. For the conventional approach the KJA was determined by applying a knee alignment device, for the functional approach subjects were asked to perform two different calibration movements. Each procedure was performed twice. Mean hip rotation in stance (mHipRotSt) was determined following the conventional and the functional KJA calibration. Deming regression analysis for the comparison of conventional and functionally measured hip rotation revealed a systematic and substantial difference between methods (slope: 0.63; intercept: 0.31°). Measurement repetition with the knee alignment device revealed typical errors around 5°, whereas the functional methods lead to profoundly smaller errors around 1-2° with slightly inferior results for SQUAT compared to FLEX. However, when compared to conventional frontal plane video-taping, the conventional method seemed to reflect the more consistent results. The systematic linear discrepancy in mHipRotSt obtained by a functional approach as compared to the conventional approach appears critical since patients with severe internal or external rotation gait may be misjudged in function when receiving corrective procedures such as femoral derotation osteotomy. • Gait analysis was performed in 95 subjects with and without rotational malalignments. • A conventional and two functional approaches were applied for knee axis determination. • Hip rotation differs almost by a factor of two between approaches (linear slopes 0.63; 0.71). • The outcome with a functional approach (FLEX, SQUAT) leads to a higher precision. • The outcome with the conventional approach corresponds better with clinical evaluation. [ABSTRACT FROM AUTHOR]

Limited studies have compared the muscle activity of the medial and lateral hamstrings as knee flexors with tibial internal and external rotation and hip extensors with hip internal and external rotation. In particular, hamstring activity during hip extension with hip rotation has rarely been investigated. This study aimed to compare the muscle activity of the medial and lateral hamstrings as knee flexors and hip extensors and to compare the activity of these muscles according to tibial rotation during isometric knee flexion and hip rotation during isometric hip extension. A total of 23 healthy adults participated in the study. The electromyographic (EMG) activity of the hamstrings was measured during maximal isometric knee flexion and maximal isometric hip extension. In addition, tibial rotation was applied actively during maximal isometric knee flexion, whereas hip rotation was applied actively during maximal isometric hip extension. EMG activity during maximal isometric knee flexion with tibial internal and external rotation was significantly higher than that during maximal isometric hip extension with hip internal and external rotation, respectively. For EMG activity according to tibial and hip rotation, there was no significant difference between tibial internal and external rotation during maximal isometric knee flexion, whereas there was a significant difference between hip internal and external rotation during maximal isometric hip extension. Hamstring activity was higher for knee flexors than for hip extensors. However, hip rotation during maximal isometric hip extension is an effective intervention for selective muscle activation of the medial and lateral hamstrings. [ABSTRACT FROM AUTHOR]

Background: Several variables may affect the traction force during hip arthroscopy. Specifically, the degree of hip joint rotation may influence the magnitude of traction force during hip arthroscopy. However, there is currently limited research available on this particular issue., Purpose: To quantify the traction force applied to the pulled limb in various traction states and rotational positions. Additionally, the study aimed to investigate potential correlations between femoral anteversion, BMI, anesthesia methods, and the traction force required for hip dislocation., Hypothesis: It was hypothesized that traction force in different traction states and rotational positions would be different and that femoral anteversion, body mass index (BMI), and anesthesia methods may influence the traction force needed., Study Design: Cross-sectional study; Level of evidence, 4., Methods: Patients who attended the sports medicine clinic of our department and underwent arthroscopic surgery for the diagnosis of femoroacetabular impingement between June and December 2022 were retrospectively evaluated. The traction force at the following 6 key timepoints was measured-initial traction, traction to the operable width, after joint puncture, after capsulotomy, at 20 minutes after capsulotomy, and at 40 minutes after capsulotomy. In each state, the hip was rotated to the internal rotational position, external rotational position, and neutral position. The traction force at different states and positions was recorded and analyzed. The differences in traction force between the different joint capsular physical states and rotational positions were tested by analysis of variance and the Tukey method. The Pearson test was used to analyze the correlation between BMI and femoral anteversion in different groups., Results: A total of 41 patients were included in this study. The traction force increased after reaching the operable width and decreased significantly after capsulotomy ( P < .05). Thereafter, the traction force decreased gradually over time ( P < .05). Traction force in the external and internal rotational positions was significantly greater than that in the neutral position, across all states of traction ( P < .05). Furthermore, the difference in traction force between the internal and neutral positions, as well as the difference in traction force between the external and neutral positions, was found to be significantly greater than the difference in traction force between the internal and external rotational positions in all traction states ( P < .05). The difference between the traction forces in different rotational positions of the hip joint exhibited a negative correlation with femoral anteversion (Pearson correlation coefficient of neutral-internal in states 3, 4, and 5 was -0.33, -0.31, -0.31, respectively; P < .05) and a positive correlation with BMI (Pearson correlation coefficient of external-neutral in states 4 and 6 was 0.33 and 0.36, respectively; P < .05)., Conclusion: Our findings show that the traction force decreased after joint puncture and capsulotomy and decreased over time during surgery. External or internal rotation increased the traction force. Patients with higher femoral anteversion or lower BMI may need lower traction force. These data may help in minimizing traction forces to help prevent complications due to traction during hip arthroscopy., Competing Interests: The authors declared that they have no conflicts of interest in the authorship and publication of this contribution. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2024.)

In walking in healthy adults, rotation of the hip joint affects stride length and shifts the center of gravity, but these are not seen in hip osteoarthritis which affects gait. In gait of total hip arthroplasty, there are few reports on changes in the horizontal plane. This study clarified the preoperative and early postoperative gait characteristics of patients undergoing total hip arthroplasty. The analysis included 12 females who underwent initial total hip arthroplasty using a posterolateral approach. Gait was measured pre and postoperatively using a three-dimensional motion analysis device. Statistics were compared pre and postoperative range of motion, muscle strength, walking speed, stride length, gravity movement distance, trunk angle, hip joint angle, and joint moment. The maximum hip abduction moment and trunk flexion angle to the surgical side were lower than in healthy subjects. The angle of internal rotation during the stance phase was significantly higher in the postoperative period. The distance of the center of gravity shift in the left and right directions was significantly decreased postoperatively. Gait disturbance was seen preoperatively and remained after surgery. Walking after total hip arthroplasty provides the hip joint rotates inward which is closer to normal walking. However, no change was observed in the external rotation moment of the hip joint during walking. We suspect that the invasiveness of the posterolateral approach of total hip arthroplasty affects the muscles for external rotation of the hip joint. This can also cause in gait disturbances. • The movement of the hip joint in the horizontal plane was measured quantitatively. • The internal rotation angle of the hip during gait increased after total hip arthroplasty. • The strength of the external rotators of the hip joint after total hip arthroplasty was decreased. [ABSTRACT FROM AUTHOR]

Context: Pelvic-drop exercises are often used to strengthen the gluteus medius (GM) muscle with the aim of increasing or prioritizing its recruitment. However, the effect of hip rotation on the performance of the action of the GM is unknown. Objective: To evaluate the effect of hip rotation on the recruitment of the GM, tensor fasciae latae (TFL), and quadratus lumborum (QL). Method: Seventeen healthy subjects performed 2 sets of 4 repetitions of pelvic-drop exercise in random order with pelvic-drop lateral, medial, and neutral rotation of the hip. Main Outcome Measures: The electromyographic (EMG) activity of the GM, TFL, and QL was evaluated using surface electromyography. Results: There were significant increases in the activation of the GM with medial and neutral rotation compared with lateral rotation (P = .03, P = .01, respectively), and there was no difference between medial and neutral rotation (P = 1.00). There was no difference in EMG activity of the TFL and QL in any of the positions. The GM:TFL ratio was the same in all analyzed positions. Regarding the GM:QL ratio, there was a significant increase with medial rotation compared with lateral rotation (P = .02). Conclusions: Pelvic-drop exercises are more efficient for activating the GM when the hip is in medial rotation and neutral position. [ABSTRACT FROM AUTHOR]

Abstract Background Measurement of hip rotation is a crucial clinical parameter for the identification of hip problems and the monitoring of symptoms. The objective of this study was to determine whether the use of two smartphone applications is valid and reliable for the measurement of hip rotation. Methods An experimental, cross-sectional study was undertaken to assess passive hip internal and external rotation in three positions by two examiners. The hip rotational angles were measured by a smartphone clinometer application in the sitting and prone positions, and by a smartphone compass application in the supine position; their results were compared with those of the standard, three-dimensional, motion analysis system. The validities and inter-rater and intra-rater reliabilities of the smartphone applications were evaluated. Results The study involved 24 participants. The validities were good to excellent for the internal rotation angles in all positions (ICC 0.81–0.94), good for the external rotation angles in the prone position (ICC 0.79), and fair for the sitting and supine positions (ICC 0.70–0.73). The measurement of the hip internal rotation in the supine position had the highest ICC value of 0.94 (0.91, 0.96). The two smartphone applications showed good-to-excellent intra-rater reliability, but good-to-excellent inter-rater reliability for only three of the six positions (two other positions had fair reliability, while one position demonstrated poor reliability). Conclusions The two smartphone applications have good-to-excellent validity and intra-rater reliability, but only fair-to-good inter-rater reliability for the measurement of the hip rotational angle. The most valid hip rotational position in this study was the supine IR angle measurement, while the lowest validity was the ER angle measurement in the sitting position. The smartphone application is one of the practical measurements in hip rotational angles. Trial registration Number 20181022003 at the Thai Clinical Trials Registry ( http://www.clinicaltrials.in.th ) which was retrospectively registered at 2018-10-18 15:30:29.

McHugh, MP, O'Mahoney, CA, Orishimo, KF, Kremenic, IJ, and Nicholas, SJ. Importance of transverse plane flexibility for proficiency in golf. J Strength Cond Res 36(2): e49–e54, 2022—The extent to which the flexibility requirements for golf proficiency vary between the planes of motion has not been examined. The purpose of this study was to compare flexibility between proficient and average golfers with the hypothesis that proficient golfers have greater transverse plane flexibility than average golfers, with no differences in the sagittal and frontal planes. Twenty-five male golfers were categorized as proficient (handicap ≤5, n = 13) or average (handicap 10–20, n = 12). Fourteen flexibility tests were performed (4 shoulder tests, 4 trunk tests, and 6 hip tests) with tests in all 3 planes of motion for each body segment. In addition, trunk motion, pelvic motion, and hip motion during the golf swing were assessed with high-speed motion analysis. Ball speed and shot distance were recorded with a golf simulator. Proficient golfers had significantly better flexibility than average golfers in the transverse plane (shoulder p = 0.021, trunk p = 0.003, and hip p < 0.0001), with no differences in the sagittal plane or frontal plane (plane of motion by golf proficiency p = 0.0001). Transverse plane hip flexibility accounted for 48% of the variability in ball speed (p < 0.0001) and 45% of the variability in total distance (p = 0.001). During the golf swing, proficient golfers had greater separation between the pelvis and the trunk (x-factor) than average golfers (p = 0.002). In conclusion, transverse plane flexibility in the trunk and hips is an important requirement for golf proficiency. Sagittal plane flexibility and frontal plane flexibility were unrelated to proficiency. Developing and maintaining trunk and hip rotation flexibility is important for optimizing performance. [ABSTRACT FROM AUTHOR]

Objectives Dynamic knee valgus is composed of hip-knee coupling. While females differ from males in passive hip motion, hip rotation range may alter muscle mechanics and neuromuscular activity. This study aimed to compare knee abduction biomechanics during double-legged drop-landing between males and females with different hip rotation ranges. Methods This study included five females with the range of hip internal rotation (IR) > the range of hip external rotation (ER), five females with ER>IR, four males with IR>ER, and five males with ER>IR. There was no difference in other hip motions among them or no difference in hip muscle strength between the same sex groups. Three-dimensional motion analyses of the hip and knee joints were performed during double-legged drop-landing. Results Multiple regression analysis of females with IR>ER showed that peak knee abduction moment (KAM) was associated with maximal hip abduction moment before detecting peak KAM whereas peak knee abduction angle (KAA) correlated with no variable. In females with ER>IR, peak KAM was associated with maximal hip ER moment before detecting peak KAM, hip ER muscle strength and hip adduction range while peak KAA correlated with peak hip abduction moment before detecting peak KAM. In males with IR>ER, peak KAM was associated with hip ER range and hip adductor strength whereas peak KAA correlated with maximal hip ER moment and maximal hip IR angle during landing. In males with ER>IR, peak KAM was associated with hip extensor strength, hip abduction range and hip flexion range whereas peak KAA correlated with hip ER moment before detecting peak KAM, hip ER muscle strength, and hip adduction range. Conclusions Hip rotation range may differentially affect hip-knee coupling strategy for knee abduction control during double-legged drop-landing between males and females.

BACKGROUND: In clinical practice, knee flexion at the prone position for manual muscle testing of hamstrings and hip extension at the supine position for stretching of hamstring muscles are typically proposed. OBJECTIVE: Although different positions have been proposed for different purposes in hamstrings, the understanding of the changing the functional role of hamstrings with position changes is poorly understood. METHODS: The electromyographic (EMG) activity and hip extension force were compared among different postures; hip neutral, internal, and external rotation. EMG and force were measured in prone position during knee flexion and those were additionally measured in supine position during hip extension. In supine position, additional measurements were made in hip neutral, internal and external rotation. RESULTS: Hamstrings showed high EMG activity during knee flexion. Knee flexion force in prone position was significantly decreased at hip extension force in supine position. In supine position, EMG activity was significantly higher in semitendinosus (ST) than biceps femoris (BF) during internal rotation. CONCLUSIONS: It should be noted that bi-articular muscles may have different functional dependencies on the corresponding muscles for each joint. In addition, because the altered alignment of the hamstring muscles that was affected by hip rotation had a significant effect on muscle activity, and hip rotation may be helpful for selective training of medial or lateral hamstrings. [ABSTRACT FROM AUTHOR]

Background: The clinical utility of motion capture modeling relies on the accurate tracking of segment motions. Soft tissue artefact presents a particular challenge for modeling hip rotation, knee rotation, and knee varus-valgus motions. The integration of a patella marker has been shown to significantly improve hip rotation tracking for models that utilize anatomical definitions of joint axes (e.g. anatomical models). However, these modeling improvements have not been extended to models that use functional segment motion to define joint axes (e.g. functional models).Research Question: How does the positioning of a patella marker influence functional model performance?Methods: A patella functional model (PFM) was created by integrating a patella marker into the functional model (FM) used at our center. Nine distinct versions of the PFM were created using a 3 × 3 grid of markers placed across the patella. Ten typically developing participants performed controlled hip rotation, controlled knee flexion-extension, and free speed walking trials to assess FM and PFM performance differences.Results: The top performing PFM modeled 98 ± 8 % of the reference hip rotation range of motion compared to 71 ± 9 % for the FM. This PFM had low sensitivity to knee flexion-extension motion, 5 ± 10 %. For walking kinematics, this top performing PFM reported 14 % greater hip rotation ROM during stance, 46 % less knee rotation ROM over the entire gait cycle, and 32 % less knee varus-valgus during swing compared to the FM. The differences in modeling are nearly identical to those reported between skin mounted marker and fluoroscopy-based models, indicating that utilization of the patella marker leads to improvements in tracking accuracy.Significance: Utilization of a precisely placed patella marker led to substantial improvements in modeled hip rotation, knee rotation, and knee varus-valgus. These improvements have the potential to positively impact those specialties that rely on motion capture modeling for clinical decision-making, such as orthopedic surgery. [ABSTRACT FROM AUTHOR]

Background: The effect of change in hip anatomy on change in gait pattern is not well described in current literature. Therefore, our primary aim was to describe and quantify changes in hip geometry and gait pattern 1 year after total hip arthroplasty (THA) in individuals with hip osteoarthritis. Our secondary aim was to explore the effect of postoperative change in femoral neck anteversion (FNA) and femoral offset and acetabular offset (FO/AO) quota on postoperative change in hip rotation and hip adduction moment during gait, respectively, 1 year after THA".Methods: Sixty-five individuals with primary hip osteoarthritis, scheduled for THA, were analyzed in this prospective intervention study. Participants were evaluated pre- and 1 year postoperatively with computed tomography-scans, three-dimensional gait analysis, and patient-reported outcome measures. Multiple linear regressions were performed to evaluate the association between change in joint anatomy and change in gait pattern after THA.Results: One year postoperatively, global offset was symmetrical between sides as a result of decreased acetabular offset and increased femoral offset on the operated side. Quality of overall gait pattern improved, and participants walked faster and with less trunk lean over the affected side. FNA and hip rotations during walking changed equally in external and internal directions after THA and change in hip rotation during walking was associated with change in FNA in the same direction. An increase in external hip adduction moments was, on the other hand, not associated with change in FO/AO quota but with a more upright walking position and increased walking speed.Conclusions: The findings of this study suggest that geometrical restoration during THA impacts postoperative gait pattern and, in addition to known factors such as FO, height of hip rotation center, and leg length discrepancy, the FNA must also be taken into consideration.Trial Registration: Trial registration: Clinicaltrial.gov , NCT01512550 , Registered 19 January 2012 - Retrospectively registered. [ABSTRACT FROM AUTHOR]

Background: Measurement of hip rotation is a crucial clinical parameter for the identification of hip problems and the monitoring of symptoms. The objective of this study was to determine whether the use of two smartphone applications is valid and reliable for the measurement of hip rotation.Methods: An experimental, cross-sectional study was undertaken to assess passive hip internal and external rotation in three positions by two examiners. The hip rotational angles were measured by a smartphone clinometer application in the sitting and prone positions, and by a smartphone compass application in the supine position; their results were compared with those of the standard, three-dimensional, motion analysis system. The validities and inter-rater and intra-rater reliabilities of the smartphone applications were evaluated.Results: The study involved 24 participants. The validities were good to excellent for the internal rotation angles in all positions (ICC 0.81-0.94), good for the external rotation angles in the prone position (ICC 0.79), and fair for the sitting and supine positions (ICC 0.70-0.73). The measurement of the hip internal rotation in the supine position had the highest ICC value of 0.94 (0.91, 0.96). The two smartphone applications showed good-to-excellent intra-rater reliability, but good-to-excellent inter-rater reliability for only three of the six positions (two other positions had fair reliability, while one position demonstrated poor reliability).Conclusions: The two smartphone applications have good-to-excellent validity and intra-rater reliability, but only fair-to-good inter-rater reliability for the measurement of the hip rotational angle. The most valid hip rotational position in this study was the supine IR angle measurement, while the lowest validity was the ER angle measurement in the sitting position. The smartphone application is one of the practical measurements in hip rotational angles.Trial Registration: Number 20181022003 at the Thai Clinical Trials Registry ( http://www.clinicaltrials.in.th ) which was retrospectively registered at 2018-10-18 15:30:29. [ABSTRACT FROM AUTHOR]

The use of physical assistant robots is expanding to activities of daily living. However, the risk of a user falling which can occur in various environments has not yet been considered despite this being a major concern for such robots. Therefore, this study focuses on curving motion, during which falling is more likely to occur, especially when the degree of freedom of the hip joint is restricted by the robot. We developed a physical assistant robot with an adjustable degree of freedom of hip rotation and observed the curving motions of the wearer under different joint restriction conditions. The result was statistically tested and the characteristics were extracted using factor analysis. It was noted that in the trials involving the restriction of hip rotation, the step length, pelvis yaw angle, and speed were significantly decreased with the decrease in hip rotation. However, as the participants changed their curving motion to compensate for the effect of joint restriction, the margin of stability varied slightly. This result suggested the necessity of implementing an assist algorithm that could change the gait motion to compensate and improve gait stability when curving. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare muscle activation during the squat with different hip rotations (neutral, 15, 30, and 45° of internal and external hip rotation) in subjects with and without Genu Varum deformity deformity. Surface electromyography were recorded from 32 men with (n=16) and without (n=16) Genu Varum deformity. In the Genu Varum deformity group, the squats with 30, 45 and 15° of internal rotations of the hip showed significantly greater gluteus medius activation as compared to other positions. Moreover, the tensor fascia lata activity increased with greater external rotation of the hip, and significantly more than hip internal rotations (p<0.05). For vastus medialis and vastus lateralis, both hip internal and external rotation showed a significantly greater activation compared to the neutral hip positions (p<0.05). There were significant differences in the gluteus medius:tensor fascia lata activity ratio (p=0.001) and the vastus medialis: vastus lateralis activity ratio (p=0.001) between the different hip positions in the Genu Varum deformity and healthy groups. These results demonstrate that muscle activation patterns varied significantly with the position of different hip rotation in both groups. Those with Genu Varum deformity may use this information to aid in an injury prevention strategy by choosing squat positioning that favorably alters muscle activation patterns. [ABSTRACT FROM AUTHOR]

Total hip arthroplasty (THA) is often required to decrease the excessive anatomical femoral anteversion (AA) in developmental dysplasia of the hip. Studies have recommended decreasing the AA via the use of a retroverted modular neck. However, hip rotation after THA may strengthen or weaken the effect of changing the AA. Thus, the present study analyzed the effect of a retroverted neck on AA and hip rotation. Patients who underwent THA using a straight neck (ST group) or a 15° retroverted neck (RV group) in a version changeable dual modular system (Mainstay stem, Kyocera, Kyoto, Japan) were retrospectively reviewed. After matching for age, body mass index, and surgical approach, 44 patients were included in each group. The AA and hip rotation (femoral rotational angle: FRA) were measured on CT images acquired preoperatively and 1 month after THA, and were compared between the groups. The mean ± standard deviation preoperative AA of the ST group (26.1 ± 10.7°) was significantly smaller than that of the RV group (44.2 ± 7.8°) (p < 0.001). In contrast, the postoperative AA did not significantly differ between the groups (ST group 27.5 ± 9.8°, RV group 25.1 ± 8.3°, p = 0.406). The change in FRA after THA did not significantly differ between the groups (ST group − 3.8 ± 9.9°, RV group − 3.5 ± 9.1°, p = 0.841). In conclusion, a 15° retroverted neck was useful in controlling AA in hips with excessive AA, and the change in FRA after THA did not differ between the ST group and the RV group. [ABSTRACT FROM AUTHOR]

Purpose To assess the presence of control impairment (CI) of the lumbopelvic region in the axial plane in men without low back pain (LBP) with CI in the sagittal plane. Methods: Twenty-four males, between 18 and 23 of age, BMI = normal, who did not report episodes of LBP in the 12 months prior to the study, were studied. Assessment of the sagittal control of the lumbopelvic region was performed during stand to sit. Nine participants demonstrated CI in sagittal plane and 15 did not. An active hip lateral rotation (HLR) test was performed, in which lumbopelvic rotation during HLR was assessed using a three-dimensional motion analysis system. Results: Patients with CI in sagittal plane had a greater percentage of their total lumbopelvic pelvic rotation at 60% of HLR range compared to those without CI (p < 0.05; d = 0.93). No significant differences in the total lumbopelvic and HLR range of motion were found between the groups. Conclusion: Men without LBP who experience CI of the lumbopelvic region in the sagittal plane also show CI in the axial plane. The control deficiencies were not related to the total range of lumbopelvic or HLR range of motion. [ABSTRACT FROM AUTHOR]

Hip rotation can influence gluteus medius (Gmed) muscle activity in individuals with genu varum (GV). This study examined different hip rotation positions on muscle activity during unilateral weight-bearing exercises in individuals with and without GV. Cross-sectional. Outpatient physical therapy center. Forty-six physically active males, divided between control (n = 23) and GV groups (n = 23). Surface electromyography measured Gmed and tensor fascia latae (TFL) activity during pelvic drop (PD) and wall press (WP) exercises with different hip rotations. In the control group, WP with external rotation produced greater Gmed/TFL activity compared to other rotation positions. No difference was found for Gmed/TFL with PD in controls. In the GV group, Gmed activity increased with internal rotation in PD and WP; TFL activity increased only with external rotation in WP. Internal hip rotation produced higher Gmed/TFL activity than other positions in the GV group during both exercises. Greater Gmed/TFL activity was observed in the control group than GV during PD with external rotation, and WP with neutral positioning and external rotation. WP with external rotation in controls, and PD and WP with internal hip rotation in subjects with GV, are effective exercises to optimize GMed/TFL activity. • The wall press with external hip rotation in Controls results in greater gluteus medius activation and a higher Gmed:TFL muscle activity ratio. • The gluteus medius function is altered in GVD in unilateral weight-bearing exercises. • Pelvic drop and wall press exercises increase the Gmed:TFL muscle activity ratio in GVD when the hip is in a medial position. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare measures of bilateral shoulder and hip range of motion (ROM) between youth softball pitchers and position players. Fifty-two youth softball athletes (12.7±2.1 yrs.; 160.28±10.98 cm; 59.31±15.07 kg) participated. Bilateral hip and shoulder ROM were measured among pitchers (n=29) and position players (n=23). A 2 (pitcher/position player) × 2 (dominant/non-dominant) ANOVA was performed for both internal and external rotation ROM for the shoulder and hip. Paired sample t-tests were also conducted to examine side-to-side differences in total ROM. Data revealed a significant interaction between position and side dominance. Specifically, position players have significantly more non-dominant shoulder external rotation ROM (106.92°± 9.14°) than pitchers (100.12°± 11.21°). There were no significant differences between throwing and non-throwing sides. It is important that coaches and clinicians are aware of these adaptations between overhand and underhand throwing in order to properly develop conditioning and rehabilitation programs to alleviate injury susceptibility and cater to position-specific demands. Additionally, the current data suggest many of the functional adaptations seen within older populations are not fully developed until after youth. [ABSTRACT FROM AUTHOR]

Background and purpose: In a previous study, we investigated the link between the femoral offset (FO) loss by trochanteric impaction (TI) and cut-out complication occurrence after pertrochanteric fractures. Three major factors are likely to drive to failure after intramedullary nailing (IN): fracture stability, reduction quality and osteosynthesis quality. We wanted to investigate the quality of the fracture reduction through the TI and the neck-shaft angle (NSA) measurement and correlate these parameters with the risk of mechanical failure occurrence. Materials and methods: It was a retrospective multicentric one case–one control match design study with age and gender randomization. The cases presented a mechanical failure of nailing: TI = 1 - FO fractured FO healthy in percentage. Femoral rotation was taken into account, and all TI were rotation-corrected (TIcorrected). Rotation-corrected neck-shaft angles (NSAcorrected) were calculated. The neck-shaft angle gap between the fractured and the healthy sides (NSAgap) was a ratio: NSA gap = 1 - NSA corrected NSA healthy in percentage. The tip–apex distance (TAD) was measured. Absolute values of TIcorrected and NSAgap were analyzed. Results: Twenty-one cases and 21 controls were examined. The average TIcorrected rate was 30% for the cases and 11% for the controls (p = 0.007). A 13% TIcorrected threshold had maximum specificity and sensitivity, equal to 71%. The average TAD was 27 mm for cases and 19 mm for controls (p = 0.004). The average NSAgap rate was 7% for the case group and 4% for the control group (p = 0.009). The areas under the ROC curves for TIcorrected, TAD and NSAgap were 0.73, 0.73 and 0.66, respectively. Interpretation: Closed reduction and exclusive implantation of IN do not seem optimal in case of FO or NSA restoration failure after pertrochanteric fractures. Level of evidence: Level III, case–control study. [ABSTRACT FROM AUTHOR]

Background: Complex clinical gait analysis results can be expressed as single number gait deviations by applying multivariate processing methods. The original Movement Deviation Profile (MDP) quantifies the deviation of abnormal gait using the most trusted nine dynamic joint angles of lower limbs.Research Question: Which subset of joint angles maximises the ability of the MDP to separate abnormal gait from normality? What is the effect of using the best subset in a large group of patients, and in individuals?Methods: A self-organising neural network was trained using normal gait data from 166 controls, and then the MDP of 1923 patients with cerebral palsy (3846 legs) was calculated. The same procedure was repeated with 511 combinations of the nine joint angles. The standardised distances of abnormal gait from normality were then calculated as log-transformed Z-scores to select the best combination. A mixed design ANOVA was used to assess how removing the least discriminating angle improved the separation of patients from controls. The effect of using the optimal subset of angles was also quantified for each individual leg by comparing the change in MDP to the independent FAQ levels of patients.Results: Removal of hip rotation significantly (p<0.0005) increased the separation of the patient group from normality (ΔZ-score 0.24) and also at FAQ levels 7-10 (ΔZ-score 0.38, 0.27, 0.22, 0.14). The MDP of individual patients changed in a wider range of -4.65 to 1.12 Z-scores and their change matched their independent FAQ scores, with less functional patients moving further from, and more functional patients moving closer to normality.Significance: In existing gait databases we recommend excluding hip rotation from data used to calculate the MDP. Alternatively, the calculation of hip rotation can be improved by post-hoc correction, but the ultimate solution is to use more accurate and reliable models of hip rotation. [ABSTRACT FROM AUTHOR]

Background: The increased incidence of lower extremity injury in runners compared to the general population is well documented. The amount of passive hip rotation and the position of hip flexion or extension at which it occurs may be factors related to injury incidence. Purpose: The purpose of the current study was to measure and compare hip rotation passive range of motion in male and female runners and non-runners at 0 and 90 degrees (°) of hip flexion. Study Design: Descriptive Laboratory Study. Methods: Eighteen Division II collegiate distance runners (9 female, 9 male, mean age =19.1, +/- 1.1 years) who had run for an average of 7.1 (SD=1.7) years participated in the study. Twenty non-runners (10 female, 10 male, mean age=19.6, +/- 1.1 years) from the same institution were also recruited. Passive hip internal rotation (IR) and external rotation (ER) were measured with a universal goniometer in 90° of hip flexion in a seated position, and in 0° of hip flexion in prone position. Results: There was a significant difference in IR measured in 0° of hip flexion, between runners and non-runners (F(1,37)=8.04, p=.007). Additionally, the difference in IR between males (36.68 +/-9.19 degrees) and females (45.99 +/- 9.12) was significantly different (F(1,37)=20.79, p=.001). There were no other statistically significant differences in measurements between groups. Conclusions: Collegiate runners had significantly greater passive hip IR when measured at 0° of hip flexion compared to the non-runners. Female runners had significantly greater passive hip IR compared to the male participants across both runners and non-runners. [ABSTRACT FROM AUTHOR]

Abstract Objective Due to the significant prevalence of knee disorders and patellofemoral pain syndrome, as well as the importance of quadriceps strengthening in knee rehabilitation programs, it is necessary to specify the best method to activate and strengthen the quadriceps muscles. The current study aimed at comparing the maximum generated isometric force during an active straight-leg-raising (SLR) maneuver in a sitting position by changing the hip rotational position with and without the simultaneous contraction of the ankle dorsiflexor muscles. Methodology The current study was performed on 30 healthy males recruited with a non-random and available sampling method. The maximum generated force was measured during the SLR maneuver in six compound internal and external rotations and in a neutral position with and without ankle dorsiflexor contraction. The obtained generated force was analyzed using repeated measures ANOVA. Results The generated forces in the SLR with and without contracting the ankle dorsiflexors were significantly different (p = 0.001), and taking different positions of hip rotation led to significant changes in the generated force (p = 0.005). Conclusion The adoption of external hip rotation with the contraction of ankle dorsiflexors during the SLR maneuver generated the most force. Based on the interaction of these conditions, the general recommendation is to perform the SLR exercise in an external hip rotation with the simultaneous contraction of the ankle dorsiflexors in subjects with quadriceps muscle weakness. [ABSTRACT FROM AUTHOR]

No specific hip joint anatomy has been identified as a risk factor for anterior cruciate ligament (ACL) injury in females. This study was conducted to elucidate the correlation of hip rotation with ACL injury incidence in female handball players, and to clarify the association of hip rotation with knee valgus motion, during ACL injury screening tasks, that is a strong predictor of ACL injury. Of 17 female university handball players, the 8 ACL-injured players displayed greater internal and smaller external rotation of the hip than the 9 uninjured players. Logistic regression analyses demonstrated significant association between hip rotation and ACL injury. Hip internal rotation dominance (internal rotation range is greater than external one) was found in 7 out of the 8 ACL-injured females in contrast to 3 out of the 9 uninjured. Knee valgus was induced in 24 and 22 of the 31 healthy female volunteers by vertical jump and single-leg squat tests, respectively. The knee valgus-positive females showed a smaller range of hip external rotation than the negative ones, which was significantly associated with knee valgus during the screening tests. Hip internal rotation dominance was significantly related to knee valgus induced by each screening test. In contrast to the females, male subjects showed lower rates of knee valgus induction by the screening tests, whereas there was no clear association between hip internal rotation dominance and the knee valgus induction. The present findings may indicate the important role of hip rotation measurement in identification of females at risk for ACL injury.

Background: Hip rotation kinematics during gait is a key parameter to support clinical decision making, for example in children with lower limb torsional deformities. However, hip rotation kinematics is also one of the least repeatable parameter because it is difficult to locate the position of the medio-lateral axis of the femur. Functional knee calibration provides an alternative to locate the medio-lateral axis of the femur and may be performed retrospectively, using the movement of the knee joint during gait. Although not necessarily more anatomically accurate, functional calibration may lead to increased repeatability between sessions, which would be useful to compare gait analysis data from sessions pre- and post-treatment, or to reprocess data in large gait databases.Methods: This study presents a workflow to perform knee functional calibration using knee kinematics during gait and update hip rotation kinematics accordingly. The workflow was applied to investigate the inter-subject, inter-session and inter-trial variance components of multiple calibration methods in a group a 10 typically developing children.Results: Results indicated that one or two degrees of freedom functional calibration methods were more repeatable inter-session (SD: 1.8°) than conventional calibration using the knee alignment device (SD: 4.7°). However, simulated reduced range of movement at the knee during gait increased inter-session variance for the functional calibration algorithms. Functional calibration did not provide any improvement over the conventional calibration when knee range of movement was reduced and flexion greater than 20° during gait, i.e. 'crouch gait'.Significance: The workflow presented allows the re-processing of gait analysis data using knee kinematics during gait only. The workflow may also be used to investigate functional axes of other joints, for example the ankle. [ABSTRACT FROM AUTHOR]

Background: Recent studies showed rates of recurrence of internal rotation gait (IRG) after femoral derotation osteotomy (FDO) up to 40%. Some surgeons even advice overcorrection during FDO to avoid a later recurrence.Research Question: Evaluation of the long-term development of limbs with initial overcorrection after FDO.Methods: 29 limbs of 20 children (9.9 ± 3.2 years at surgery) with IRG, cerebral palsy (CP) and more than 5° external hip rotation postoperatively were included retrospectively. A gait analysis and clinical examination were performed preoperatively (less than one year, E0), postoperatively (9-23 months, E1) and at the long-term follow-up (at least five years postoperatively, E2). Differences between those children that remained overcorrected at E2 and those with a hip rotation within normal range at E2 were evaluated.Results: At E2 41% of these limbs remained overcorrected, 52% showed a hip rotation within normal range and 7% showed recurrence of IRG. A comparison of those limbs that remained overcorrected and those ending within normal range revealed neither a difference in age at surgery nor in static and dynamic torsional parameters at E0 and E1 except for pelvic rotation. A significantly larger pelvic internal rotation at E1 for those with remaining overcorrection could be identified.Significance: A general overcorrection during FDO in children with CP to avoid recurrence of IRG cannot be recommended, as 41% remain overcorrected. Preoperative predictors for long-term development couldn't be identified. If pelvic mal-rotation is corrected, hip rotation may change into normal range over the time in combination with the development of a flexed knee gait. [ABSTRACT FROM AUTHOR]

Background: Internal rotation of the hip and lateral patellar tilt increases after total hip arthroplasty (THA). However, it remains unknown whether these parameters change with time after the index THA.Methods: A total of 91 patients undergoing 2-stage bilateral primary THAs between January 2008 and May 2014 were included to assess the association of chronological changes in internal rotation of the hip or lateral patellar tilt with anthropometric and perioperative parameter and changes in alignment after the index THA. Chronological changes were assessed as changes between postoperative computed tomography on the index surgery and the preoperative computed tomography on the contralateral THA. Internal rotation of the hip was defined as the angle between the posterior intercondylar line and a line passing through the posterior inferior iliac spines. Lateral patellar tilt was defined as the angle between the posterior intercondylar line and a line joining the medial and lateral edges of the patella.Results: Internal rotation of the hip and lateral patellar tilt changed until 2 years after the index surgery by a mean of -2° (range -17.3° to 17.7°) and -2° (range -18.2° to 5.3°), respectively. Adductor tenotomy was associated with increasing internal rotation of the hip with time (adjusted R2 0.076); leg lengthening and larger preoperative femorotibial angle were associated with decreasing lateral patellar tilt with time (adjusted R2 0.159).Conclusion: Both internal rotation of the hip at rest and lateral patellar tilt decreased by approximately 2° until 2 years after surgery and there was a large variation in chronological change. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to investigate the characteristics of biomechanical and clinical measurements in relation to the knee adduction moment when wearing a standard shoe and a shoe design for individuals with knee osteoarthritis (Flex-OA).Methods: Kinematic and kinetic data were collected from thirty-two healthy individuals (64 knees) using a ten camera motion analysis system and four force plates. Subjects performed 5 walking trials under the two conditions and the magnitude of individuals' biomechanical responses where explored in relation to the clinical assessment of the Foot Posture Index, hip rotation range, strength of hip rotators, and active ankle-foot motion, all of which have been described as possible compensation mechanisms in knee osteoarthritis.Results: Significant reductions in the first peak of the knee adduction moment (KAM) during stance phase (9.3%) were recorded (p<0.0001). However, despite this difference, 22 of 64 knees showed either no change or an increased KAM, indicating a non-response or negative-response to the Flex-OA shoe. Significant differences were observed between the responder and non-responder subgroups in the hip rotation range ratio (p=0.044) and the hip rotators strength ratio (p=0.028).Conclusion: Significant differences were seen in clinical assessments of hip rotation range and hip rotator strength between responders and non-responders using a cut-off of 0.02Nm/kg change in the KAM. [ABSTRACT FROM AUTHOR]

Background: Modern knee designs do not fully restore the anatomy and kinematics of the natural knee. This study evaluates the kinematic and kinetic changes of well-functioning patients with total knee arthroplasty (TKA) in comparison to a healthy age-matched control group while descending stairs and level walking. The aim was to have a baseline for further investigations of TKA patients with problems.Methods: Fifteen patients satisfied with TKA (8♀/7♂; 66.8 ± 7.4 years; body mass index (BMI) 25.9 ± 2.8 kg/m2; 2.1 ± 1.3 years postop, LCS Complete) and 17 healthy control subjects (7♀/10♂; 66.6 ± 6.8 years; BMI 25.0 ± 2.2 kg/m2) participated in the study. Kinematic (upper and lower body) and kinetic (lower body) data were collected during stair descending (step height 17 cm) and level walking, using an 8-camera Vicon system and 2 force plates. Parameters were compared using a Student t test.Results: Patients after TKA showed significantly lower frontal knee moments and a more externally rotated hip during stance for both level walking and stair descent. There were 31% more significantly different parameters during level walking than during stair descent.Conclusion: The analysis of stair descending in addition to level walking for satisfied patients does not add additional information for the understanding of the kinematic and kinetic changes after TKA. It seems more important to include the kinematics and kinetics of the hip and ankle joint in all 3-dimensional planes. [ABSTRACT FROM AUTHOR]