Patients with cam-type femoroacetabular impingement demonstrate increased change in bone-to-bone distance during walking: A dual fluoroscopy study

Protocol and validity testing of femoroacetabular posterior translation with dynamic hip ultrasonography

OBJECTIVE

To describe femoroacetabular posterior translation (FAPT) using dynamic hip ultrasonography (DHUS), and to determine the inter- and intra-rater reliability of hip ultrasound measurements of FAPT.

MATERIALS AND METHODS

The study design was a feasibility study of 13 healthy young adults (26 hips) using test-retest analysis. The data was collected prospectively over a 2-week time period. Three DHUS measurements (posterior neutral (PN), flexion, adduction, and internal rotation (PFADIR), and stand and load (PStand) were measured by four independent raters (2 senior who divided the cohort, 1 intermediate, 1 junior) at two time points for bilateral hips of each participant. Reliability was assessed by calculating the intraclass correlation coefficient (ICC) along with 95% confidence intervals (CIs) for each rater and across all raters.

RESULTS

A total of 468 US scans were completed. The mean age of the cohort was 25.7 years (SD 5.1 years) and 54% were female. The inter-rater reliability was excellent for PFADIR (ICC 0.85 95% CI 0.76-0.91), good for PN (ICC 0.69 95% CI 0.5-0.81), and good for PStand (ICC 0.72 95% CI 0.55-0.83). The intra-rater reliability for all raters was good for PFADIR (ICC 0.60 95% CI 0.44-0.73), fair for PN (ICC 0.42 95% CI 0.21-0.59), and fair for PStand (ICC 0.42 95% CI 0.22-0.59).

CONCLUSION

This is the first study to present a protocol using dynamic ultrasonography to measure FAPT. DHUS measure for FAPT was shown to be reliable across raters with varying levels of ultrasound experience.

Hip and Pelvis Movement Patterns in Patients With Femoroacetabular Impingement Syndrome Differ From Controls and Change After Hip Arthroscopy During a Step-Down Pivot-Turn Task

Background

Alterations in hip kinematics during functional tasks occur in positions that cause anterior impingement in patients with femoroacetabular impingement (FAI) syndrome. However, tasks that do not promote motions of symptomatic hip impingement remain understudied.

Purpose

To compare movement patterns of the hip and pelvis during a step-down pivot-turn task between patients with FAI and controls as well as in patients with FAI before and after hip arthroscopy.

Study Design

Controlled laboratory study.

Methods

Three-dimensional motion capture was acquired in 32 patients with FAI and 27 controls during a step-down pivot-turn task. An FAI subsample (n = 14) completed testing 9.2 ± 2.0 months (mean ± SD; range, 5.8-13.1 months) after hip arthroscopy. Statistical parametric mapping analysis was used to analyze hip and pelvis time series waveforms (1) between the FAI and control groups, (2) in the FAI group before versus after hip arthroscopy, and (3) in the FAI group after hip arthroscopy versus the control group. Continuous parametric variables were analyzed by paired t test and nonparametric variables by chi-square test.

Results

There were no significant differences in demographics between the FAI and control groups. Before hip arthroscopy, patients with FAI demonstrated reduced hip flexion (P = .041) and external rotation (P = .027), as well as decreased anterior pelvic tilt (P = .049) and forward rotation (P = .043), when compared with controls. After hip arthroscopy, patients demonstrated greater hip flexion (P < .001) and external rotation of the operative hip (P < .001), in addition to increased anterior pelvic tilt (P≤ .036) and pelvic rise (P≤ .049), as compared with preoperative values. Postoperatively, the FAI group demonstrated greater hip flexion (P≤ .047) and lower forward pelvic rotation (P = .003) as compared with the control group.

Conclusion

Movement pattern differences between the FAI and control groups during the nonimpingement-related step-down pivot-turn task were characterized by differences in the sagittal and transverse planes of the hip and pelvis. After hip arthroscopy, patients exhibited greater hip flexion and external rotation and increased pelvic anterior tilt and pelvic rise as compared with presurgery. When compared with controls, patients with FAI demonstrated greater hip flexion and lower pelvic forward rotation postoperatively.

Clinical Relevance

These findings indicate that hip and pelvis biomechanics are altered even during tasks that do not reproduce the anterior impingement position.

Association of Changes in Hip and Knee Kinematics During a Single-Leg Squat With Changes in Patient-Reported Outcomes at 6 Months and 1 Year After Hip Arthroscopy

BACKGROUND

Previous studies have demonstrated alterations in squat kinematics in patients with femoroacetabular impingement syndrome (FAIS). Little is known about the effects of arthroscopic hip surgery on biomechanics during a single-leg squat (SLS) in these patients.

PURPOSE/HYPOTHESIS

The purpose of this study was to determine if (1) lower extremity dynamic range of motion (ROM) during an SLS task improves after hip arthroscopy for FAIS and (2) correlations exist between changes in patient-reported outcomes (PROs) and changes in lower extremity dynamic ROM during an SLS after hip arthroscopy for FAIS. It was hypothesized that dynamic hip ROM would improve after hip arthroscopy and that hip dynamic ROM would be associated with changes in PRO scores at both 6 months and 1 year.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Patients with FAIS performed 3 SLSs that were analyzed using a 20-camera motion capture system. Dynamic ROMs were calculated in 3 planes for the hip, knee, ankle, and pelvic segments. Squat depth was calculated as the change in vertical center of mass during the squat cycle. PROs including the Hip Outcome Score-Activities of Daily Living (HOS-ADL), Hip Outcome Score-Sports (HOS-Sports), International Hip Outcome Tool-12, and visual analog scale for pain scores were collected preoperatively and at the time of postoperative testing. Paired-samples t tests were used to compare kinematic variables pre- and postoperatively. Correlations were used to compare changes in PROs with changes in kinematics. All statistical analysis was performed using SPSS Version 26.

RESULTS

Fifteen patients were tested preoperatively and at a mean of 9 months postoperatively. All PRO measures improved postoperatively at 6 months and 1 year. Squat depth and sagittal plane hip and knee dynamic ROMs were significantly improved postoperatively. Positive correlations existed between changes in (1) hip ROM with the 6-month HOS-ADL score (r = 0.665) and (2) knee ROM with the 6 month (r = 0.590) and 1-year (r = 0.565) HOS-Sports scores.

CONCLUSION

Dynamic sagittal plane hip and knee ROMs improve after hip arthroscopy for FAIS. These improvements demonstrate strong correlations with improvements in some but not all postoperative PROs.

CLINICAL RELEVANCE

The current study sought to better understand the role of dynamic movement in the diagnosis and treatment of FAIS. These findings indicate that dynamic ROM and squat depth can, similarly to PROs, serve as biomarkers for patient function both before and after hip arthroscopic surgery.

A Correspondence-Based Network Approach for Groupwise Analysis of Patient-Specific Spatiotemporal Data

Methods for statistically analyzing patient-specific data that vary both spatially and over time are currently either limited to summary statistics or require elaborate surface registration. We propose a new method, called correspondence-based network analysis, which leverages particle-based shape modeling to establish correspondence across a population and preserve patient-specific measurements and predictions through statistical analysis. Herein, we evaluated this method using three published datasets of the hip describing cortical bone thickness of the proximal femur, cartilage contact stress, and dynamic joint space between control and patient cohorts to evaluate activity- and group-based differences, as applicable, using traditional statistical parametric mapping (SPM) and our proposed spatially considerate correspondence-based network analysis approach. The network approach was insensitive to correspondence density, while the traditional application of SPM showed decreasing area of the region of significance with increasing correspondence density. In comparison to SPM, the network approach identified broader and more connected regions of significance for all three datasets. The correspondence-based network analysis approach identified differences between groups and activities without loss of subject and spatial specificity which could improve clinical interpretation of results.

Biomechanical Analysis of Hip Braces after Hip Arthroscopic Surgery for Femoroacetabular Impingement Syndrome: An Observational Study

Currently, hip braces are recommended and typically worn by femoroacetabular impingement (FAI) patients after hip arthroscopic surgery. However, there is currently a lack of literature regarding the biomechanical effectiveness of hip braces. The purpose of this study was to investigate the biomechanical effect of hip braces after hip arthroscopic surgery for FAI. Overall, 11 patients who underwent arthroscopic FAI correction and labral preservation surgery were included in the study. Standing-up and walking tasks in unbraced and braced conditions were performed at 3 weeks postoperatively. For the standing-up task, videotaped images of the hip's sagittal plane were recorded while patients stood from a seated position. After each motion, the hip flexion-extension angle was calculated. For the walking task, acceleration of the greater trochanter was measured using a triaxial accelerometer. For the standing-up motion, the mean peak hip flexion angle was found to be significantly lower in the braced condition than in the unbraced condition. Furthermore, the mean peak acceleration of the greater trochanter was significantly lower in the braced condition than in the unbraced condition. Patients undergoing arthroscopic FAI correction surgery would benefit from usage of a hip brace in terms of protecting repaired tissues during early postoperative recovery.

A novel method for in vivo measurement of dynamic ischiofemoral space based on MRI and motion capture

Purpose: To use a novel in vivo method to simulate a moving hip model. Then, measure the dynamic bone-to-bone distance, and analyze the ischiofemoral space (IFS) of patients diagnosed with ischiofemoral impingement syndrome (IFI) during dynamic activities. Methods: Nine healthy subjects and 9 patients with IFI were recruited to collect MRI images and motion capture data. The motion trail of the hip during motion capture was matched to a personalized 3D hip model reconstructed from MRI images to get a dynamic bone model. This personalized dynamic in vivo method was then used to simulate the bone motion in dynamic activities. Validation was conducted on a 3D-printed sphere by comparing the calculated data using this novel method with the actual measured moving data using motion capture. Moreover, the novel method was used to analyze the in vivo dynamic IFS between healthy subjects and IFI patients during normal and long stride walking. Results: The validation results show that the root mean square error (RMSE) of slide and rotation was 1.42 mm/1.84° and 1.58 mm/2.19°, respectively. During normal walking, the in vivo dynamic IFS was significantly larger in healthy hips (ranged between 15.09 and 50.24 mm) compared with affected hips (between 10.16 and 39.74 mm) in 40.27%-83.81% of the gait cycle (p = 0.027). During long stride walking, the in vivo dynamic IFS was also significantly larger in healthy hips (ranged between 13.02 and 51.99 mm) than affected hips (between 9.63 and 44.22 mm) in 0%-5.85% of the gait cycle (p = 0.049). Additionally, the IFS of normal walking was significantly smaller than long stride walking during 0%-14.05% and 85.07%-100% of the gait cycle (p = 0.033, 0.033) in healthy hips. However, there was no difference between the two methods of walking among the patients. Conclusions: This study established a novel in vivo method to measure the dynamic bone-to-bone distance and was well validated. This method was used to measure the IFS of patients diagnosed with IFI, and the results showed that the IFS of patients is smaller compared with healthy subjects, whether in normal or long stride walking. Meanwhile, IFI eliminated the difference between normal and long stride walking.