[Hip joint biomechanical analysis of the acetabular anatomical reconstruction and nonanatomical reconstruction in total hip arthroplasty for Crowe type â ¢ developmental dysplasia of the hip by finite element method].

OBJECTIVE: To analyze the hip joint biomechanics of the acetabular anatomical reconstruction and nonanatomical reconstruction in total hip arthroplasty (THA) for Crowe type Ⅲ developmental dysplasia of the hip (DDH) by finite element method, which provided theoretical foundation and experimental basis for the anatomical acetabular reconstruction during THA in clinical practice. METHODS: One patient with left end-stage hip arthritis secondary to Crowe type Ⅲ DDH was selected in this study, who underwent total hip arthroplasty in the orthopedic department of the First Affiliated Hospital of Bengbu Medical College in April 2020. This patient was female, 57 years old. The preoperative and postoperative three dimentional CT scan of the patient's pelvis were performed. Fourteen acetabular cup models with different anteversion, inclination and rotation center height were established in Mimics and 3-Matic software. The boundary and load conditions were set in Abaqus software. The Von Mises and stress distribution of the hip joint were calculated and observed. RESULTS: In the Crowe type Ⅲ DDH THA, if the hip rotation center was restored anatomically and the acetabular cup's inclination was set as 40°, the cup's anteversion varied from 5° to 25°, the lowest Von Mises value of acetabular cup and polyethylene liner occured in 20°anteversioin;if the hip rotation center was restored anatomically and the acetabular cup's anteversion was set as 15°, the cup's inclination varied from 35° to 55°, the lowest Von Mises value of acetabular cup and polyethylene liner occured in 35° inclination;if the acetabular cup's anteversion and inclination were set as 15°and 40°respectively, the up migration of hip rotaion center varied from 0 mm to 20 mm, the lowest Von Mises value of acetabular cup and polyethylene liner occured in 10 mm up migration. In all fourteen models, the Von Mises value of the acetabulum, acetabulum cup and polyethylene liner were lowest when the acetabular cup's anteversion and inlcination were 15°, 35° respectively, as well as the rotation center was restored anatomically. CONCLUSION: In total hip arthroplasty for Crowe type Ⅲ DDH, the anatomical restoration of hip rotation center with 15° anteversion and 35° inclination of the acetabular cup are suggested, bone graft above the acetabular cup and additional screws are recommended simultaneously to further reduce the Von Mises of hip joint.

Effect of stiffness-optimized ankle foot orthoses on joint work in adults with neuromuscular diseases is related to severity of push-off deficits.

BACKGROUND: People with plantar flexor weakness generate less ankle push-off work during walking, resulting in inefficient proximal joint compensations. To increase push-off work, spring-like ankle foot orthoses (AFOs) can be provided. However, whether and in which patients AFOs increase push-off work and reduce compensatory hip and knee work is unknown. METHODS: In 18 people with bilateral plantar flexor weakness, we performed a 3D gait analysis at comfortable walking speed with shoes-only and with AFOs of which the stiffness was optimized. To account for walking speed differences between conditions, we compared relative joint work of the hip, knee and ankle joint. The relationships between relative work generated with shoes-only and changes in joint work with AFO were tested with Pearson correlations. RESULTS: No differences in relative ankle, knee and hip work over the gait cycle were found between shoes-only and AFO (p>0.499). Percentage of total ankle work generated during pre-swing increased with the AFO (AFO: 85.3±9.1% vs Shoes: 72.4±27.1%, p=0.026). At the hip, the AFO reduced relative work in pre-swing (AFO: 31.9±7.4% vs Shoes: 34.1±10.4%, p=0.038) and increased in loading response (AFO: 18.0±11.0% vs Shoes: 11.9±9.8%, p=0.022). Ankle work with shoes-only was inversely correlated with an increase in ankle work with AFO (r=-0.839, p<0.001) and this increase correlated with reduction in hip work with AFO (r=-0.650, p=0.004). DISCUSSION: Although stiffness-optimized AFOs did not alter the work distribution across the ankle, knee and hip joint compared to shoes-only walking, relative more ankle work was generated during push-off, causing a shift in hip work from pre-swing to loading response. Furthermore, larger ankle push-off deficits when walking with shoes-only were related with an increase in ankle work with AFO and reduction in compensatory hip work, indicating that more severely affected individuals benefit more from the energy storing-and-releasing capacity of AFOs.

Effect of Spinopelvic Parameters on Outcomes After Hip Arthroscopy for Femoroacetabular Impingement Syndrome.

BACKGROUND: Spinopelvic parameters, including pelvic tilt (PT), sacral slope (SS), and pelvic incidence, have been developed to characterize the relationship between lumbar spine and hip motion, but a paucity of literature is available characterizing differences in spinopelvic parameters among patients with femoroacetabular impingement syndrome (FAIS) versus patients without FAIS, as well as the effect of these parameters on outcomes of arthroscopic treatment of FAIS. PURPOSE: To (1) identify differences in spinopelvic parameters between patients with FAIS versus controls without FAIS; (2) identify associations between spinopelvic parameters and preoperative patient-reported outcomes (PROs); and (3) identify differences in PROs between patients with stiff spines (standing-sitting ΔSS ≤10°) versus those without. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: The study enrolled patients ≥18 years of age who underwent primary hip arthroscopy for treatment of FAIS with cam, pincer, or mixed (cam and pincer) morphology. Participants underwent preoperative standing-sitting imaging with a low-dose 3-dimensional radiography system and were matched on age and body mass index (BMI) to controls without FAIS who also underwent EOS imaging. Spinopelvic parameters measured on EOS films were compared between the FAIS and control groups. Patients with FAIS completed the modified Harris Hip Score (mHHS) and Non-Arthritic Hip Score (NAHS) before surgery and at 1-year follow-up. Outcome scores were compared between patients with stiff spines versus those without. Associations between spinopelvic parameters and baseline outcome scores were assessed with Pearson correlations. Continuous variables were compared with Student t test and/or Mann-Whitney U test, and categorical variables were compared with Fisher exact test. RESULTS: A total of 50 patients with FAIS (26 men; 24 women; mean age, 36.1 ± 10.7 years; mean BMI, 25.6 ± 4.2) were matched to 30 controls without FAIS (13 men; 17 women; mean age, 36.6 ± 9.5 years; mean BMI, 26.7 ± 3.6). Age, sex, and BMI were not significantly different between the FAIS and control groups (P > .05). Standing PT was not significantly different between stiff and non-stiff cohorts (P = .73), but sitting PT in the FAIS group was more than double that of the control group (36.5° vs 15.0°; P < .001). Incidence of stiff spine was significantly higher in the FAIS group (62.0% vs 3.3%; P < .001). Among FAIS patients, those with stiff spines had a significantly higher prevalence of cam impingement, whereas those with non-stiff spines had a higher prevalence of mixed impingement (P = .04). No significant differences were seen in preoperative mHHS or NAHS scores or pre- to postoperative improvement in scores between FAIS patients with stiff spines versus those without (P > .05), but a greater sitting SS was found to be positively correlated with a higher baseline mHHS (r = 0.36; P = .02). CONCLUSION: Patients with FAIS were more likely to have a stiff spine (standing-sitting ΔSS ≤10°) compared with control participants without FAIS. FAIS patients with stiff spines were more likely to have isolated cam morphology than patient without stiff spines. Although sitting SS was positively correlated with baseline mHHS, no significant differences were seen in 1-year postoperative outcomes between FAIS patients with versus without stiff spine.

Hip biomechanics in patients with low back pain, what do we know? A systematic review.

BACKGROUND: Biomechanical alterations in patients with low back pain (LBP), as reduced range of motion or strength, do not appear to be exclusively related to the trunk. Thus, studies have investigated biomechanical changes in the hip, due to the proximity of this joint to the low back region. However, the relationship between hip biomechanical changes in patients with LBP is still controversial and needs to be summarized. Therefore, the aim of this study was to systematically review observational studies that used biomechanical assessments in patients with non-specific LBP. METHODS: The search for observational studies that evaluated hip biomechanical variables (i.e., range of motion, kinematic, strength, and electromyography) in adults with non-specific acute, subacute, and chronic LBP was performed in the PubMed, Embase, Cinahl and Sportdiscus databases on February 22nd, 2024. Four blocks of descriptors were used: 1) type of study, 2) LBP, 3) hip and 4) biomechanical assessment. Two independent assessors selected eligible studies and extracted the following data: author, year of publication, country, study objective, participant characteristics, outcomes, and results. The methodological quality of the studies was assessed using the Epidemiological Appraisal Instrument and classified as low, moderate, and high. Due to the heterogeneity of the biomechanical assessment and, consequently, of the results among eligible studies, a descriptive analysis was performed. RESULTS: The search strategy returned 338 articles of which 54 were included: nine articles evaluating range of motion, 16 evaluating kinematic, four strength, seven electromyography and 18 evaluating more than one outcome. The studies presented moderate and high methodological quality. Patients with LBP, regardless of symptoms, showed a significant reduction in hip range of motion, especially hip internal rotation, reduction in the time to perform functional activities such as sit-to-stance-to-sit, sit-to-stand or walking, greater activation of the hamstrings and gluteus maximus muscles and weakness of the hip abductor and extensor muscles during specific tests and functional activities compared to healthy individuals. CONCLUSION: Patients with LBP present changes in range of motion, task execution, activation, and hip muscle strength when compared to healthy individuals. Therefore, clinicians must pay greater attention to the assessment and management of the hip during the treatment of these patients. SYSTEMATIC REVIEW REGISTRATION: International Prospective Register of Systematic Reviews (PROSPERO) (CRD42020213599).

Reliability of Hip Strength Assessment in Young Active People with Hip Dysplasia: An Examination in Student Circus Artists.

BACKGROUND: Developmental dysplasia of the hip (DDH) is common in performing artists and other young active individuals and involves abnormalities in bony morphology of the acetabulum and proximal femur that can negatively impact walking biomechanics, muscular strength, quality of life, and sleep. Rehabilitation for hip-related conditions should target known modifiable impairments such as hip muscle strength, though a reliable method of assessment in this population remains unclear. OBJECTIVE: To determine the inter- and intra-rater reliability of hip muscle strength assessments using handheld dynamometry (HHD) in young active circus artists with DDH. METHODS: Reliability of hip strength in all planes was assessed using HHD in 21 adult performing circus arts students (mean age 21.3 yrs [3.2]; 13 M, 5 F, 3 NB) with symptomatic radiologically and clinically diagnosed hip dysplasia. The reliability of average peak force and absolute peak force were expressed for each position tested. Reliability was assessed using intraclass correlation coefficients (ICC) with standard error of measurement (SEM) and minimal detectable change (MDC) values calculated to improve clinical interpretability. RESULTS: Good to excellent inter-rater reliability resulted for all hip muscle strength testing positions, ICC=0.88 (95%CI 0.70 to 0.95) to ICC=0.97 (0.92 to 0.99), except average peak hip flexion strength, ICC=0.71 (0.28 to 0.88). Absolute peak hip abduction, ICC=0.77 (0.16 to 0.94), and adduction strength, ICC=0.72 (-0.55 to 0.92), demonstrated the lowest intra-rater reliability. Transverse plane strength measures (rotation) produced the lowest SEM and MDC values followed by the frontal plane (abduction/adduction) and sagittal plane (flexion/extension). CONCLUSION: HHD is an appropriate and reliable method to assess hip muscle strength in circus artists with DDH.

The applicability of markerless motion capture for clinical gait analysis in children with cerebral palsy.

The aim of this comparative, cross-sectional study was to determine whether markerless motion capture can track deviating gait patterns in children with cerebral palsy (CP) to a similar extent as marker-based motion capturing. Clinical gait analysis (CGA) was performed for 30 children with spastic CP and 15 typically developing (TD) children. Marker data were processed with the Human Body Model and video files with Theia3D markerless software, to calculate joint angles for both systems. Statistical parametric mapping paired t-tests were used to compare the trunk, pelvis, hip, knee and ankle joint angles, for both TD and CP, as well as for the deviation from the norm in the CP group. Individual differences were quantified using mean absolute differences. Markerless motion capture was able to track frontal plane angles and sagittal plane knee and ankle angles well, but individual deviations in pelvic tilt and transverse hip rotation as present in CP were not captured by the system. Markerless motion capture is a promising new method for CGA in children with CP, but requires improvement to better capture several clinically relevant deviations especially in pelvic tilt and transverse hip rotation.

Sex-based differences in neck selectivity in total hip arthroplasty using a modular femoral neck system.

BACKGROUND: Dislocation is a major complication of total hip arthroplasty (THA). The modular femoral neck system provides practical advantages by allowing adjustment of neck version and length in the presence of intraoperative instability. Anatomical studies have identified morphological differences in the hip joint between men and women. Despite sex-based differences in hip morphology, it remains unclear whether such differences affect neck selectivity in THA using a modular neck system and whether this approach achieves anatomical reconstruction, thereby reducing complications such as dislocation. This study aimed to investigate gender differences in neck selectivity in THA with the modular neck system and assess the clinical impact of the modular neck system. METHODS: A total of 163 THAs using a modular neck system were included in this study. Data on the type of modular neck and intraoperative range of motion (ROM) were retrieved from patient records. Pre- and post-operative leg length differences (LLD) were examined as part of the radiographic assessment. Dislocation was investigated as a postoperative complication. RESULTS: Neck selectivity did not significantly differ between men and women. The comparison of pre- and post-operative LLD revealed a tendency for varus necks to improve LLD more than version-controlled necks. Furthermore, no significant correlation was found between intraoperative ROM and neck selectivity, or postoperative dislocation and neck selectivity. CONCLUSIONS: This study on THA with a modular neck system provided valuable insights into sex-based differences in neck selectivity and highlighted the potential benefits of the modular neck system in addressing LLD and preventing postoperative dislocation.

Influence of acetabular and femoral morphology on pelvic tilt.

Aims: The aim of this study was to investigate whether anterior pelvic plane-pelvic tilt (APP-PT) is associated with distinct hip pathomorphologies. We asked: is there a difference in APP-PT between young symptomatic patients being evaluated for joint preservation surgery and an asymptomatic control group? Does APP-PT vary among distinct acetabular and femoral pathomorphologies? And does APP-PT differ in symptomatic hips based on demographic factors? Methods: This was an institutional review board-approved, single-centre, retrospective, case-control, comparative study, which included 388 symptomatic hips in 357 patients who presented to our tertiary centre for joint preservation between January 2011 and December 2015. Their mean age was 26 years (SD 2; 23 to 29) and 50% were female. They were allocated to 12 different morphological subgroups. The study group was compared with a control group of 20 asymptomatic hips in 20 patients. APP-PT was assessed in all patients based on supine anteroposterior pelvic radiographs using validated HipRecon software. Values in the two groups were compared using an independent-samples t-test. Multiple regression analysis was performed to examine the influences of diagnoses and demographic factors on APP-PT. The minimal clinically important difference (MCID) for APP-PT was defined as > 1 SD. Results: There were no significant differences in APP-PT between the control group and the overall group (1.1° (SD 3.0°; -4.9° to 5.9°) vs 1.8° (SD 3.4°; -6.9° to 13.2°); p = 0.323). Acetabular retroversion and overcoverage groups showed higher mean APP-PTs compared with the control group (p = 0.001 and p = 0.014) and were the only diagnoses with a significant influence on APP-PT in the stepwise multiple regression analysis. All differences were below the MCID. The age, sex, height, weight, and BMI showed no influence on APP-PT. Conclusion: APP-PT showed no radiologically significant variation across different pathomorphologies of the hip in patients being assessed for joint-preserving surgery.

Can a clinical assessment predict the functional status progression in patients with femoroacetabular impingement syndrome?

BACKGROUND: Femoroacetabular impingement syndrome (FAIS) is a hip joint motion-related clinical disorder with a triad of symptoms, clinical signs, and imaging findings. However, scientific evidence is still unclear regarding the best treatment for FAIS. OBJECTIVES: To assess the value of a physical therapy evaluation in predicting the progression of functional status over the subsequent years in patients with FAIS who are candidates for hip arthroscopy surgery. METHODS: In this case-series study, patients with FAIS, candidates for hip arthroscopy surgery, underwent a standard physical therapy evaluation. Baseline data were collected between 2013 and 2019. In 2020/2021, the patients' functional status was assessed through the International Hip Outcome Tool (iHOT-33). Functional status progression was calculated as the difference between the follow-up and baseline iHOT-33 scores. A multivariate forward stepwise regression analysis was conducted to explore the relationship between baseline characteristics and the functional status progression. RESULTS: From 353 patients who completed the baseline assessment, 145 completed the iHOT-33 follow-up. The mean (±SD) follow-up time was 58.7 (27.2) months (minimum 12 and maximum 103 months). The iHOT-33 scores increased 20.7 (21.8) points on average, ranging from -39.8 to 76.9 points. Among the 15 potential predictive factors assessed in this study, only baseline iHOT-33 score (ß -0.44; -0.061, -0.27), femoral version (ß 9.03; 1.36, 16.71), and body mass index (ß -0.99; -1.98, -0.01) had the ability to predict the functional status progression. CONCLUSION: Patients with a lower baseline iHOT-33 score, lower body mass index, and normal femoral version were more likely to increase their functional status after a minimum of one year of follow-up.

Analysis on association between sagittal stem alignment and early functional and radiological outcome following primary cementless total hip replacement.

INTRODUCTION: Accurate reconstruction of hip anatomy and biomechanics is mandatory for achieving good clinical outcomes following total hip replacement (THR). Optimal stem alignment is essential to avoid impingement or loosening. This study aimed to evaluate sagittal stem position following cementless THR and its relationship with patient's functional outcome and post-operative radiological parameters. METHOD: We performed analytical observational study with cross-sectional design on 71 hips (67 patients, ranged 18-85 years old) that underwent primary cementless THR in two orthopedic centers in Jakarta, Indonesia. All hips were operated through either anterolateral or posterior approach using either extended/full-coating wedge-tapered stem or proximal-coated wedge-tapered stem. Clinical outcomes were evaluated at follow-up time using mHHS questionnaire, VAS level of thigh pain, and hip ROM. Stem sagittal alignment and other radiological parameters, including combined anteversion and offset, were measured from conventional radiograph. RESULTS: There were no significant differences on mHHS score, VAS level on thigh pain, and ROM between stem alignment groups. Post-operative anteversion and offset of the implant were not affected by the stem sagittal position. All influencing factors have significant effect on sagittal stem alignment. Linear regression test on femur morphology showed 0.69° increase in stem posterior tilt for every 1° increase in the anterior bowing (coeff. = 0.502). CONCLUSION: Stem tilting in sagittal plane did not affect patient's functional outcome or post-operative radiological parameters. In addition, for every degree of increased anterior femoral bowing, 0.69° increase in posterior stem tilting can be expected.

Calipered kinematic alignment restored the arithmetic hip-knee-ankle angle, achieved high satisfaction and improved clinical outcomes.

PURPOSE: The purpose of this study was to determine whether unrestricted calipered kinematic alignment (KA), coupled with a medial-stabilised (MS) implant system, can reproduce the patient's constitutional alignment as per the arithmetic hip-knee-ankle (aHKA) and improve clinical outcomes. METHODS: One-hundred and ninety-three patients received total knee arthroplasty by the senior author. To determine whether the constitutional alignment was achieved, the postoperative hip-knee-ankle (HKA) alignment was compared against the aHKA. Range of motion (ROM) was determined preoperative and postoperatively at 6 months and 2 years by measuring the active flexion and extension. Patient-Reported Outcomes Measures (PROMs) including Oxford Knee Score (OKS), Knee Injury and Osteoarthritis Outcome Score (KOOS), Forgotten Joint Score (FJS) and Visual Analogue Scale for Satisfaction were also completed. The Sports and Recreation component of KOOS was used to assess the patient's ability to return to sports and daily activities. RESULTS: There was a strong correlation between postoperative HKA and aHKA (r = 0.7, p < 0.05). There was a significant improvement in both extension and flexion seen from as early as 6 months postoperatively, with a mean flexion of 123° ± 11° and extension of 1° ± 3° at 2 years. PROMs had significant improvements with a mean score of 42.8 ± 6.0 for the OKS and all KOOS subscales consisting of Symptoms (88.0 ± 11.7), Pain (91.4 ± 11.6), Activities of Daily Living (91.1 ± 12.4), Sports (76.8 ± 22.1) and Quality of Life (83.0 ± 19.1). The FJS had significant improvements from 6 months to 2 years of 19.9 (p < 0.05), with a mean score of 69.2 ± 26.6 at 2 years. Ninety-three percent (180 patients) were classified as 'satisfied' at the 2-year timepoint. The KOOS Sports component was completed by 64% (124 patients), whereby the mean age was younger than the noncompliant patients (67.7 ± 9.4 vs. 71.7 ± 8.2 years). CONCLUSION: Unrestricted calipered KA can result in an alignment that closely resembles the patient's constitutional alignment, as per the aHKA. This resulted in improved knee ROM and patient satisfaction, as well as assisting younger patients to return to sports and daily activities. LEVEL OF EVIDENCE: Level IV.

Minimally invasive treatment for idiopathic chondrolysis of the hip: analysis of forty-one cases.

PURPOSE: Idiopathic chondrolysis of the hip is characterized by the loss of the articular cartilage of the hip joint with spectrum ranging from full recovery to fibrous ankylosis. Study assessed outcomes following intra-articular steroid injections, joint manipulation and traction immobilization. METHODS: Retrospective (2012-2021) review of 41 cases treated for idiopathic chondrolysis of hip, assessed pre-operatively and post-operatively (minimum 2-year follow-up) using Children's Hospital Oakland Hip Evaluation Score (CHOHES), visual analogue scale (VAS) and range of motion measurements. RESULTS: Twenty-five patients (62%) achieved painless mobility, 6 (14%) had hip stiffness without pain and 10 (24%) had painful and stiff hips at final follow-up. They had a mean age of 12.49 ± 2.4 years and a mean follow-up duration of 33.15 ± 13.1 months. Range of motion improved significantly (p < 0.05). VAS improved to 3.93 ± 1.3 from 7.8 ± 0.7. CHOHES improved from 29.12 ± 9.9 to 56.37 ± 17.6. CONCLUSION: Intra-articular steroid injection, manipulation and traction immobilization may effectively treat idiopathic chondrolysis of the hip by enhancing patient function and reducing the need for further surgical intervention.

Hip contact forces can be predicted with a neural network using only synthesised key points and electromyography in people with hip osteoarthritis.

OBJECTIVE: To develop and validate a neural network to estimate hip contact forces (HCF), and lower body kinematics and kinetics during walking in individuals with hip osteoarthritis (OA) using synthesised anatomical key points and electromyography. To assess the capability of the neural network to detect directional changes in HCF resulting from prescribed gait modifications. DESIGN: A calibrated electromyography-informed neuromusculoskeletal model was used to compute lower body joint angles, moments, and HCF for 17 participants with mild-to-moderate hip OA. Anatomical key points (e.g., joint centres) were synthesised from marker trajectories and augmented with bias and noise expected from computer vision-based pose estimation systems. Temporal convolutional and long short-term memory neural networks (NN) were trained using leave-one-subject-out validation to predict neuromusculoskeletal modelling outputs from the synthesised key points and measured electromyography data from 5 hip-spanning muscles. RESULTS: HCF was predicted with an average error of 13.4 ± 7.1% of peak force. Joint angles and moments were predicted with an average root-mean-square-error of 5.3 degrees and 0.10 Nm/kg, respectively. The NN could detect changes in peak HCF that occur due to gait modifications with good agreement with neuromusculoskeletal modelling (r2 = 0.72) and a minimum detectable change of 9.5%. CONCLUSION: The developed neural network predicted HCF and lower body joint angles and moments in individuals with hip OA using noisy synthesised key point locations with acceptable errors. Changes in HCF magnitude due to gait modifications were predicted with high accuracy. These findings have important implications for implementation of load-modification based gait retraining interventions for people with hip OA in a natural environment (i.e., home, clinic).

Mobility of the lumbo-pelvic-hip complex (spinopelvic mobility) and sagittal spinal alignment - implications for surgeons performing hip arthroplasty.

INTRODUCTION: The optimal positioning of the hip prosthesis components is influenced by the mobility and balance of the spine. The present study classifies patients with pathology of the spino-pelvic-hip complex, showing possible methods of preventing hip dislocations after arthroplasty. HYPOTHESIS: Hip-Spine Classification helps arthroplasty surgeons to implant components in more patient-specific position. MATERIALS AND METHODS: The group of 100 patients treated with total hip arthroplasty. Antero-posterior (AP) X-rays of the pelvis in a standing position, lateral spine (standing and sitting) and AP of the pelvis (supine after the procedure) were analyzed. We analyzed a change in sacral tilt value when changing from standing to sitting (∆SS), Pelvic Incidence (PI), Lumbar Lordosis (LL) Mismatch, sagittal lumbar pelvic balance (standing position). Patients were classified according to the Hip-Spine Classification. Postoperatively, the inclination and anteversion of the implanted acetabular component were measured. RESULTS: In our study 1 A was diagnosed in 61% of all cases, 1B in 18%, 2 A in 16%, 2B in 5%. 50 out of 61 (82%) in group 1 A were placed within the Levinnek "safe zone". In 1B, 2 A, 2B, the position of the acetabular component was influenced by both the spinopelvic mobility and sagittal spinal balance. The mean inclination was 43.35° and the anteversion was 17.4°. CONCLUSIONS: Categorizing patients according to Hip-Spine Classification one can identify possible consequences the patients at risk. Pathology of the spino-pelvic-hipcomplex can lead to destabilization or dislocation of hip after surgery even though implanted according to Lewinnek's indications. Our findings suggest that Lewinnek safe zone should be abandoned in favor of the concept of functional safe zones.

Lower limbs biomechanical deficits associated with stage 1 and 2 posterior tibialis tendon dysfunction during walking.

BACKGROUND: Posterior tibialis tendon dysfunction (PTTD) is a chronic degenerative musculoskeletal disorder causing a progressive ankle complex and arch collapse altering lower limb biomechanics. However, biomechanical changes associated with stage 1 and 2 PTTD need to be better characterized during walking to guide clinical recommendations and improve non-operative treatments. RESEARCH QUESTION: What are the lower limb kinematic and kinetic differences between individuals with stage 1 (PTTD1), individuals with stage 2 PTTD (PTTD2) and healthy counterparts during gait? METHODS: Sixteen PTTD1, 11 PTTD2 and 20 healthy controls were included in this multicentric case-control study to compare their lower limb gait biomechanics. Kinematic and kinetic data were recorded using a three-dimensional motion capture system and a force plate. One-dimensional statistical parametric mapping was used to compare lower limb joint motion and moments between groups during the stance phase. RESULTS: PTTD1 had minimal biomechanical differences compared with the control group. In contrast, PTTD2 presented significant differences compared with controls and PTTD1. At the ankle, PTTD2 exhibited greater plantarflexion and eversion angles and midfoot dorsiflexion and inversion angles throughout stance compared with controls and PTTD1. PTTD2 presented lower midfoot abduction moments compared with controls. These changes led PTTD2 to exhibit knee and hip adaptative biomechanical mechanisms in the frontal and transverse planes in late stance. PTTD2 had greater knee internal rotation angles and smaller knee external rotation moments compared to controls. PTTD2 had smaller hip internal rotation angles compared with PTTD1 and smaller hip adduction moments compared with controls. SIGNIFICANCE: PTTD1 showed minimal biomechanical differences compared to controls and important differences compared to PTTD2. The lower limb biomechanical deficits accentuate as the pathology advances from stage 1 to stage 2. PTTD is a progressive condition needing early clinical management at stage 1 to avoid successive biomechanical changes associated with stage 2.

Investigating pelvic drop gait abnormality in adolescent hip pathology patients.

BACKGROUND: Trendelenburg gait describes contralateral pelvic drop during single leg stance (SLS) with occasional lateral trunk lean compensation over the stance limb. However, quantitative research on 'uncompensated Trendelenburg' gait (pelvic drop independent of lateral trunk lean) remains sparse among populations that commonly utilize this gait pattern, such as adolescent hip pathology patients. RESEARCH QUESTION: How prevalent is uncompensated Trendelenburg among various adolescent hip pathologies and how is it related to hip load, hip abduction strength, and self-reported hip pain? METHODS: Gait, strength, and pain data were collected among 152 pre-operative patients clinically diagnosed with acetabular hip dysplasia, femoroacetabular impingement, Legg-Calvé-Perthes, or slipped capital femoral epiphysis (SCFE). Patients with ≥ 5.4° of dynamic pelvic drop in SLS were divided into a 'pelvic drop' group and screened to exclude those with excessive ipsilateral trunk lean. They were then compared to the 'stable pelvis' patients using a Mann-Whitney test. RESULTS: Dysplasia patients represented the highest proportion of the pelvic drop group (46%). The pelvic drop group showed a significant increase in self-reported hip pain (p = 0.011), maximum hip abductor moment (p = 0.002), and peak coronal power absorption at the affected hip during SLS loading response, (p < 0.001) while showing no difference in abduction strength (p = 0.381). SIGNIFICANCE: Uncompensated Trendelenburg gait may lead to increased loading of the affected hip in adolescent hip pathology patients. Disadvantageous hip biomechanics can create increased abductor muscle demand among these pathological populations, with dysplasia patients showing the highest prevalence. Maximal abduction strength did not correlate with pelvic drop. Future work should aim to identify and quantify causal factors. Increased coronal hip power absorption during weight acceptance warrants clinical attention, as there may be a detrimental, over-reliance on passive hip structures to support load among a population that that is already predisposed to hip osteoarthritis.

Clinical Outcomes Following Incomplete Arthroscopic Iliotibial Band Release for External Snapping Hip Syndrome: An Observational Study.

OBJECTIVES: Arthroscopic treatment is indicated for external snapping hip (ESH) syndrome in patients refractory to conservative treatment, but snapping does not disappear completely in some case. No previous studies have described the clinical course of ESH syndrome in patients who presented with persistent snapping after an arthroscopic procedure. We demonstrated the clinical outcomes following an incomplete arthroscopic iliotibial band (ITB) release for ESH syndrome. METHODS: This retrospective observational study was performed at two teaching hospitals between October 2015 and December 2021. We reviewed the data of 33 patients (34 hips) aged ≥18 years, diagnosed with ESH syndrome, who were treated with arthroscopic ITB release. Patients who presented with persistent snapping despite sufficient arthroscopic ITB release following systematic order were defined as having an incomplete release. We collected the data for recurrent symptomatic snapping hip as the primary outcome after a minimum 2-year follow-up. The visual analogue scale (VAS) and modified Harris hip (mHHS) scores were measured as secondary outcome. RESULTS: "Incomplete release" was identified in three of the 34 hips (8.9%). Cases of recurrent symptomatic snapping or conversion to open surgery were not observed. The symptoms of residual snapping spontaneously disappeared in all cases following routine postoperative rehabilitation within a 3-month follow-up period. The VAS (4 ± 1) and mHHS (17 ± 6) scores of all the patients improved. CONCLUSION: When refractory ESH syndrome is identified during arthroscopic surgery, appropriate ITB release and removal of the major lesion causing snapping are expected to lead to resolution of residual symptoms without conversion to open surgery.

A New Computed Tomography-Based Measure that Provides Insight Into Hip Stability in Patients With Posterior Wall Acetabular Fractures.

OBJECTIVES: To describe the technique and results of a new sagittal plane computed tomography (CT)-based angular measure for predicting stability after posterior wall acetabular fractures (PWF). DESIGN: Retrospective review. SETTING: Academic Level II trauma center. PATIENT SELECTION CRITERIA: Fifty-eight consecutive patients with PWF (AO/OTA class 62A.1), 98% were high-energy injuries. INTERVENTION: A new sagittal CT measure of PWF based on the angle subtending the joint center, cranial and caudal fracture exits. OUTCOME MEASURES AND COMPARISONS: Hip incongruity or dislocation demonstrated using gold standard test, examination under anesthesia (EUA), or instability on static images. Prediction of hip instability using a sagittal CT angular measure based on cranial and caudal fracture exits was compared with previous axial CT measures suggestive of increased risk for instability including posterior wall size >50%, and those with cranial exit within 5.0 mm of the acetabular dome. RESULTS: There were 32 operative and 26 nonoperatively treated fractures. Thirty fractures were determined to be unstable, and 28 were stable after EUA. Measurements of >70 degrees using the sagittal CT angular measure predicted instability in 28 of 28 patients, and ≤70 degrees predicted stability in 30 of 30 patients (sensitivity 100% and specificity 100%). Prevalence of EUA confirmed instability for subgroups with PWF based on prior axial CT measures were as follows: ≥50% wall involvement (11/16; sensitivity 67% and specificity 60%; 95% CI, 45%-89%/45%-75%), fracture within 5.0 mm of dome (5/18; sensitivity 86% and specificity 73%; 95% CI, 71%-100%/59%-87%), fracture within 5.0 mm of dome and ≥50% involvement (1/9; sensitivity 89% and specificity 56%; 95% CI, 69%-100%/24%-88%). CONCLUSIONS: In a sample of 58 mostly high energy posterior wall fractures all having had an EUA, a new sagittal angular CT measurement of ≤70 degrees predicted hip stability and >70 degrees predicted instability with 100% sensitivity and specificity. LEVEL OF EVIDENCE: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.