Gait analysis in patients after bilateral versus unilateral total hip arthroplasty

Impact of spinal-hip types on gait patterns in patients with end-stage hip disease

BACKGROUND

Patients with end-stage hip disease are classified into distinct spinal-hip types according to sagittal spinal-hip parameters. Each type employs specific compensatory strategies to maintain balance, but the associated alterations in gait patterns remain unclear. This study characterized the gait differences among patients with different spinal-hip types.

METHODS

This prospective observational study used EOS imaging to obtain full-length sagittal images and classify patients into spinal-hip types. The study included 10 patients in each type (A, B, and C) and 10 healthy controls. Gait analysis was performed to evaluate the spatiotemporal and kinematic parameters, followed by the gait profile score (GPS) analysis. The Kruskal-Wallis test was used to compare relevant parameters across the four groups, with post-hoc comparisons conducted using the Bonferroni method.

RESULTS

Significant differences among the types were observed in stride length (P = 0.003), stance phase percentage (P = 0.001), and swing phase percentage (P < 0.001), with type C showing the shortest stride and type A exhibiting the shortest stance phase. The sagittal range of motion (ROM) of the pelvis and hip varied significantly across the gait cycle (both P < 0.001), with type A exhibiting the largest pelvic ROM and the smallest hip ROM. Types A and C showed lower sagittal center of mass displacement during the stance phase (P < 0.001). Type A exhibited the most restricted knee ROM during the swing phase (P < 0.001). The GPS was highest in type A, followed by type C, while type B and healthy controls had the lowest scores (P < 0.001).

CONCLUSIONS

Patients with different spinal-hip types exhibited distinct gait adaptations to compensate for sagittal deformities. Patients with severe sagittal imbalance exhibited compensatory increased pelvic swing and demonstrated diminished functional scores. Preoperative assessment is essential for optimizing total hip arthroplasty outcomes and guiding rehabilitation.

Gait improvements in the early post-surgery rehabilitation phase in subjects receiving a total knee or hip arthroplasty: A prospective study

BACKGROUND

Rehabilitation after total knee arthroplasty (TKA) and total hip arthroplasty (THA) is fundamental for reducing pain and recovering strength, range of motion, and walking ability. Gait analysis (GA) is rarely included in the rehabilitation path. This study assesses how inpatient rehabilitation influences clinical outcomes and gait analysis (GA) parameters in TKA and THA patients, comparing these with age- and speed-matched healthy subjects (HS).

METHODS

A prospective observational study included 80 subjects (50 TKA, 30 THA) and 20 aged-matched HS. Assessments occurred at admission and discharge post inpatient rehabilitation, using clinical outcome scales (e.g., Modified Barthel Index, Knee Society Score), GA spatiotemporal parameters, and gait summary measures (e.g., Gait Profile Score, Gait Deviation Index). Statistical analyses determined the significance of improvements.

RESULTS

Post-rehabilitation, significant improvements were observed in clinical outcomes and some key spatio-temporal gait parameters (p ≤ 0.01). However, gait summary measures showed no changes. Interestingly, gait summary measures did not correlate with clinical outcome scales. Moreover, TKA and THA patients showed no differences compared with slow-walking HS.

CONCLUSION

Inpatient rehabilitation significantly enhanced clinical outcomes and spatio-temporal parameters. Additionally, no differences were observed between spatiotemporal and gait summary measures of slow-walking HS and patients at discharge, indicating that rehabilitation restored gait quality. However, gait speed remains impaired, in both TKA and THA populations. Future research should explore personalized rehabilitation protocols to address these limitations and improve gait outcomes.

TRIAL REGISTRATION NUMBER

NCT04803578.

Assessment of a New Gait Asymmetry Index in Patients After Unilateral Total Hip Arthroplasty

Background/Objectives: Comparing a given variable between the lower extremities (LEs) usually involves calculating the value of a selected asymmetry index. The aim of this study was to evaluate the mean-dependent asymmetry index for gait variables. Methods: The three-point crutch gait asymmetry between the non-surgical LE (NS) and surgical LE (S) was assessed in 14 patients after unilateral total hip arthroplasty. An eight-camera motion capture system integrated with two force platforms was used. The values of the new gait asymmetry index (MA) were calculated for such variables as stance phase time (ST), knee flexion and extension range of motion (KFE RoM), hip flexion and extension range of motion (HFE RoM), and vertical ground reaction force (VGRF). Results: An analysis related to gait asymmetry showed significantly higher values for all variables for the NS than for the S (the MA ranged from 9.9 to 42.0%; p < 0.001). In the case of comparisons between the MA and other indices, the intraclass correlation coefficient ranged from 0.566 to 0.998 (p < 0.001) with Bland-Altman bias values that ranged from -18.2 to 0.3 %GC (ST), from 0.0 to 0.5° (KFE RoM), from -12.4 to 1.4° (HFE RoM), and from -11.9 to -0.1 %BW (VGRF). Conclusions: The findings revealed a prominent three-point crutch gait asymmetry for all variables, especially a disturbingly large asymmetry for the HFE RoM and VGRF. The comparisons also showed generally excellent or good agreement with the other indices. Furthermore, the mean MA result from n single values was the same as the MA result calculated using the mean values of a given variable. The MA, as an accurate asymmetry index, can be used to objectively assess pathological gait asymmetry.

Impaired Perception of Body-Weight Distribution Marks Functional Mobility Problems in Patients Undergoing Total Hip Arthroplasty

Hip osteoarthritis and total hip arthroplasty imply damaged articular and periarticular structures responsible for proprioception, and this damage may impair the accurate perception of body-weight distribution. In this study, we investigated proprioceptive abilities and accuracy perceiving body-weight distribution in patients undergoing total hip arthroplasty, and we assessed the associations between these abilities and body perception accuracy with functional mobility testing in 20 patients scheduled for total hip arthroplasty and 20 age-matched healthy participants. We assessed (a) absolute error in hip joint position sense (AE-JPS), (b) absolute error in body-weight distribution (AE-BWD) during standing and sit-to-stand tasks with open and closed eyes, and (c) functional mobility with the Timed Up and Go Test (TUG). We assessed patients undergoing hip arthroplasty before (T0) and five days after their surgery (T1), while control participants underwent a single evaluation. Relative to controls, participants undergoing surgery showed higher AE-JPS at 15° of hip flexion at T0 (p = .003) and at T1 (p = .007), greater AE-BWD during sit-to-stand with open eyes at T1 (p = .014) and with closed eyes at both T0 (p = .014) and at T1 (p < .001), and worse TUG at both T0 (p = .009) and T1 (p < .001). AE-BWD during sit-to-stand with closed eyes positively correlated with TUG at T0 (r = 0.55, p = .011) and at T1 (r = 0.51, p = .027). These findings suggested that impairments in body-weight distribution perception were evident both before and immediately after total hip arthroplasty, suggesting that these impairments may regularly mark these patients' functional mobility problems.

Functional assessment in patients undergoing total hip arthroplasty

Aims

Conventional patient-reported surveys, used for patients undergoing total hip arthroplasty (THA), are limited by subjectivity and recall bias. Objective functional evaluation, such as gait analysis, to delineate a patient's functional capacity and customize surgical interventions, may address these shortcomings. This systematic review endeavours to investigate the application of objective functional assessments in appraising individuals undergoing THA.

Methods

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were applied. Eligible studies of THA patients that conducted at least one type of objective functional assessment both pre- and postoperatively were identified through Embase, Medline/PubMed, and Cochrane Central database-searching from inception to 15 September 2023. The assessments included were subgrouped for analysis: gait analysis, motion analysis, wearables, and strength tests.

Results

A total of 130 studies using 15 distinct objective functional assessment methods (FAMs) were identified. The most frequently used method was instrumented gait/motion analysis, followed by the Timed-Up-and-Go test (TUG), 6 minute walk test, timed stair climbing test, and various strength tests. These assessments were characterized by their diagnostic precision and applicability to daily activities. Wearables were frequently used, offering cost-effectiveness and remote monitoring benefits. However, their accuracy and potential discomfort for patients must be considered.

Conclusion

The integration of objective functional assessments in THA presents promise as a progress-tracking modality for improving patient outcomes. Gait analysis and the TUG, along with advancing wearable sensor technology, have the potential to enhance patient care, surgical planning, and rehabilitation.

Motion acquisition of gait characteristics one week after total hip arthroplasty: a factor analysis

INTRODUCTION

Clinical gait analysis can be used to evaluate the recovery process of patients undergoing total hip arthroplasty (THA). The postoperative walking patterns of these patients can be significantly influenced by the choice of surgical approach, as each procedure alters distinct anatomical structures. The aim of this study is twofold. The first objective is to develop a gait model to describe the change in ambulation one week after THA. The secondary goal is to describe the differences associated with the surgical approach.

MATERIALS AND METHODS

Thirty-six patients undergoing THA with lateral (n = 9), anterior (n = 15), and posterior (n = 12) approaches were included in the study. Walking before and 7 days after surgery was recorded using a markerless motion capture system. Exploratory Factor Analysis (EFA), a data reduction technique, condensed 21 spatiotemporal gait parameters to a smaller set of dominant variables. The EFA-derived gait domains were utilized to study post-surgical gait variations and to compare the post-surgical gait among the three groups.

RESULTS

Four distinct gait domains were identified. The most pronounced variation one week after surgery is in the Rhythm (gait cycle time: + 32.9 % ), followed by Postural control (step width: + 27.0 % ), Phases (stance time: + 11.0 % ), and Pace (stride length: -  9.3 % ). In postsurgical walking, Phases is statistically significantly different in patients operated with the posterior approach compared to lateral (p-value = 0.017) and anterior (p-value = 0.002) approaches. Furthermore, stance time in the posterior approach group is significantly lower than in healthy individuals (p-value < 0.001).

CONCLUSIONS

This study identified a four-component gait model specific to THA patients. The results showed that patients after THA have longer stride time but shorter stride length, wider base of support, and longer stance time, although the posterior group had a statistically significant shorter stance time than the others. The findings of this research have the potential to simplify the reporting of gait outcomes, reduce redundancy, and inform targeted interventions in regards to specific gait domains.

Bilateral simultaneous hip arthroplasty shows comparable early outcome and complication rate as staged bilateral hip arthroplasty for patients scored ASA 1-3 if performed by a high-volume surgeon

PURPOSE

The aim of this study was to compare early outcomes after simultaneous and staged hip arthroplasty (THA) in patients with bilateral symptomatic pathology.

METHODS

We conducted a retrospective cohort study including all patients scheduled for primary THA for bilateral hip osteoarthritis (OA, n = 290). Patients either received simultaneous (n = 152, 52.4%) or staged (n = 138, 47.6%) bilateral THA based on individual preference. All operations (n = 428) were performed by one single, high-volume surgeon. Demographic data (e.g., age, ASA score) as well as perioperative parameters (haemoglobin drop (Hb), red blood cell transfusion, length of stay (LOS), operation time, six week complication rate and achievement of inpatient rehabilitation key points) were evaluated.

RESULTS

Patients in the simultaneous bilateral THA group were younger (62.8 ± 8.9 vs. 65 ± 9.7 years, p = 0.022) and had lower ASA scores (1.8, (34.2% ASA 1, 55.3% ASA 2, 37.2% ASA 3) vs. 2.0 (18.8% ASA 1, 61.6% ASA 2, 19.6% ASA 3)) than the staged group. While the average LOS was 7.1 ± 1.7 days for simultaneous bilateral THA, the combined LOS for the staged group was 12.9 ± 2.4 days (p < 0.001). The cumulative operation time in the simultaneous bilateral THA group was 61.1 ± 11.5 min and 57.6 ± 7.3 min in the staged group (p < 0.015). Cumulative Hb loss was significantly higher in the staged group (2.1 ± 7.2 g/dl vs. 3.7 ± 1.3 g/dl, p < 0.001). No significant differences were found concerning the complication rate or early inpatient rehabilitation.

CONCLUSION

Simultaneous bilateral hip arthroplasty in patients with symptomatic bilateral hip osteoarthritis is as safe and successful as a staged procedure if performed by a high-volume surgeon.

Incidence and predictors of blood transfusions in one-stage bilateral total hip arthroplasty: a single center prospective cohort study

INTRODUCTION

The safety of performing one-stage bilateral total hip arthroplasty (THA) remains controversial among the orthopedic community. The aim of the present study was to determine the incidence and predictors of blood transfusions in one-stage bilateral THA performed in a high-volume single center.

PATIENTS AND METHODS

Patients undergoing one-stage bilateral THA between 2015 and 2017 were included. The following data were collected from the hospital medical records: age, body mass index (BMI), American Society of Anaesthesiologists (ASA) score, smoking habit, comorbidities, preoperative serum creatinine, serum iron, ferritin, C-reactive protein (CRP), and hemoglobin (Hb). The Hb levels at postoperative day 1 and 3 were also collected.

RESULTS

A total of 367 patients with a mean age of 56.1 years (range, 32-79) were included. Forty-eight (13%) patients were transfused with a mean number of 1.6 blood units per patient. In non-transfused patients, the average Hb drop was 3.6 (SD ± 1) g/dL and 4.9 g/dL (SD ± 1.3) at postoperative day 1 and day 3, respectively. The average preoperative Hb level was 14.64 (SD ± 1.21) g/dL. In the univariate logistic regression, the following variables were predictive factors for transfusions: male gender (OR 0.447; P = 0.01), preoperative hemoglobin level (OR 0.622; P = 0.001), preoperative ferritin level (OR 0.995; P = 0.016), BMI (OR 0.837; P = 0.001), cardiopathy (OR 3.534; P = 0.046), preoperative anaemia (OR 10.54; P = 0.011). In the multivariate logistic regression only preoperative hemoglobin level (OR 0.666; P = 0.01), and BMI (OR 0.868; P = 0.007) were statistically significant.

CONCLUSIONS

The incidence of blood transfusions after one-stage bilateral THA is low in non-anemic patients operated on at a high-volume arthroplasty center. The main predictors of blood transfusions are preoperative Hb level and BMI.

Is simultaneous bilateral total hip arthroplasty deleterious in a biomechanical point of view? A comparative gait analysis study

Purpose

Uni- or bilateral hip osteoarthritis is a common disease generating pain, stiffness, and functional disabilities. Changes in the normal walking with higher energy expenditures are observed. Facing a cruel lack of biomechanical data, we decided to analyse the impact on the walking of single and simultaneous bilateral total hip arthroplasties (THA).

Method

We conducted a prospective monocentric study, comparing two matched groups of 15 patients able to walk with symptomatic isolated uni- (group 1) or bilateral HO (group 2) and treated respectively by unilateral THA (UTHA) or simultaneous bilateral THA (SBTHA). Surgery was performed by a single surgeon with a direct anterior approach and approved by local ethical committee. Walking was assessed by a « 3D Gait analysis motion» pre and at 6 months post operatively.

Result

In the UTHA group, recovery, i.e., efficiency of locomotor mechanism (p < 0.001) and pelvis sagittal balance (p = 0.031) improved, while external and total work (p = 0.010) decreased post operatively. In the SBTHA group, speed (p = 0.035), step length (p = 0.046), range of motion of knee sagittal stance (p = 0.009) and hip frontal (p = 0.031), and internal work are significatively higher (p < 0.001) post operatively.

Conclusions

This original study attests that THA has a positive impact on walking and energetics outcome in UTHA and SBTHA.

Static and dynamic pelvic kinematics after one-stage bilateral or unilateral total hip arthroplasty

INTRODUCTION

The pelvis rotates simultaneously around both hips along sagittal, frontal and transversal planes and its kinematics change in patients after total hip arthroplasty (THA). Consequently, it is reasonable to expect different pelvic kinematic profiles in bilateral or unilateral THA. Therefore, the aim of this study was to compare pelvic kinematics in patients with bilateral or unilateral THA.

METHODS

40 patients undergoing bilateral (n = 20) or unilateral (n = 20) THA were evaluated for pelvic kinematics during standing and walking tasks using an optoelectronic system. Mean pelvic orientation was assessed during standing, whereas the Gait Variable Score (GVS), maximum and minimum peaks, range and values of pelvic tilt, obliquity and rotation during Heel-Strike and Toe-Off phases of gait cycle were calculated during walking. Data were collected the day before and at seven days after surgery.

RESULTS

At baseline, no between-group differences were found. At 7 days, GVS for pelvic tilt (p = 0.029) and rotation (p = 0.046) were closer to normative data in bilateral patients, who also revealed lower maximum peak of anterior tilt (p = 0.013) and lower range of pelvic tilt during gait (p = 0.031) with respect to unilateral cases. No between-group differences were found for pelvic orientation during standing at any time-point.

CONCLUSIONS

Bilateral patients revealed more physiological pelvic kinematics than unilateral cases. These findings underline the advantage of patients undergoing 1-stage bilateral THA and may be helpful in selecting personalised rehabilitative approaches.

Factors Affecting the Length of Convalescent Hospital Stay Following Total Hip and Knee Arthroplasty

Objectives

: An important role of convalescent rehabilitation wards is the short-term improvement of mobility and activities of daily living (ADL). We aimed to identify predictors associated with the length of stay (LOS) in a convalescent hospital after total hip and knee arthroplasty.

Methods

: This study included 308 patients hospitalized in a convalescent ward following total hip or total knee arthroplasty. The following factors were examined: age, sex, orthopedic comorbidities, motor component of the functional independence measure (M-FIM), M-FIM gain, pain, 10-m walk test, timed up and go (TUG) test, functional ambulation category (FAC), cognitive function, and nutritional status. LOS was categorized as shorter (≤40 days) or longer (>40 days), based on the national average LOS in a convalescent ward, and was statistically analyzed with predictor variables.

Results

: In our hospital, the average LOS was 36.9 ± 21.4 days, and the average M-FIM at admission to the convalescent ward and the M-FIM gain were 71.1 ± 7.0 and 16.3 ± 6.9, respectively. In univariate analysis, there was a significant correlation between LOS and M-FIM at admission and M-FIM gain, pain, TUG time, and FAC. Logistic multivariate analysis identified M-FIM at admission (odds ratio [OR] 0.93, 95% confidence interval [CI] 0.88–0.98) and TUG time (OR 1.10, 95% CI 1.03–1.18) as independent predictors of LOS.

Conclusions

: The M-FIM and TUG test can be used to accurately estimate LOS and to plan rehabilitation treatment in a convalescent rehabilitation ward after lower-limb arthroplasty. Furthermore, preoperative or early postoperative intervention may lead to better quality motor activity and shorter LOS during the convalescent period.

Cross-Domain Self-Supervised Complete Geometric Representation Learning for Real-Scanned Point Cloud Based Pathological Gait Analysis

Accurate lower-limb pose estimation is a prerequisite of skeleton based pathological gait analysis. To achieve this goal in free-living environments for long-term monitoring, single depth sensor has been proposed in research. However, the depth map acquired from a single viewpoint encodes only partial geometric information of the lower limbs and exhibits large variations across different viewpoints. Existing off-the-shelf three-dimensional (3D) pose tracking algorithms and public datasets for depth based human pose estimation are mainly targeted at activity recognition applications. They are relatively insensitive to skeleton estimation accuracy, especially at the foot segments. Furthermore, acquiring ground truth skeleton data for detailed biomechanics analysis also requires considerable effort. To address these issues, we propose a novel cross-domain self-supervised complete geometric representation learning framework, with knowledge transfer from the unlabelled synthetic point clouds of full lower-limb surfaces. The proposed method can significantly reduce the number of ground truth skeletons (with only 1\%) in the training phase, meanwhile ensuring accurate and precise pose estimation and capturing discriminative features across different pathological gait patterns compared to other methods.

The Symmetry and Predictive Factors in Two-Stage Bilateral Hip Replacement Procedures

Background: Approximately 10–25% of total hip replacement patients undergo a bilateral procedure. The purpose of this study was to compare selected parameters associated with the first and second hip arthroplasty in patients undergoing two-stage treatment due to bilateral hip osteoarthritis and establish the predictive factors for the second procedure. Methods: This study compared the data on bilateral total hip replacement surgeries conducted in the period between 2017 and 2021 (42 patients). The following parameters from the first and second procedure were compared: the prosthetic stem, head, and insert cup size; type of cup insert; duration of anesthesia; duration of hospitalization; and the number of complications. Results: The mean duration of hospital stay at the time of the first total hip arthroplasty was 5.83 days and 5.4 days during the second stay. The mean stem sizes used during the first and second total hip replacement procedures were 7.11 and 7.09, respectively. The mean sizes of endoprosthetic cups used at the first and second total hip replacement procedures were 52.64 and 53.04, respectively. There were no significant differences between the mean prosthetic head size at the first and second surgery. The cup type used during the first and second surgery showed no difference. The mean duration of anesthesia used during the first and second total hip replacement surgery was 108.09 min and 104.52 min, respectively. We recorded a mean of 0.07 complications per patient at the first surgery and 0.02 at the second surgery. Conclusions: Our study results showed symmetry duration of anesthesia, length of hospital stay, number of complications per patient, stem size, prosthetic head size, cup insert size, and cup insert type at the first and second surgery in patients with two-stage bilateral total hip arthroplasty. We observed a strong correlation between the stem sizes of the first and second hip endoprostheses. There was also a strong correlation between the cup sizes used during the first and second surgery.

Technological advancements in the analysis of human motion and posture management through digital devices

Technological development of motion and posture analyses is rapidly progressing, especially in rehabilitation settings and sport biomechanics. Consequently, clear discrimination among different measurement systems is required to diversify their use as needed. This review aims to resume the currently used motion and posture analysis systems, clarify and suggest the appropriate approaches suitable for specific cases or contexts. The currently gold standard systems of motion analysis, widely used in clinical settings, present several limitations related to marker placement or long procedure time. Fully automated and markerless systems are overcoming these drawbacks for conducting biomechanical studies, especially outside laboratories. Similarly, new posture analysis techniques are emerging, often driven by the need for fast and non-invasive methods to obtain high-precision results. These new technologies have also become effective for children or adolescents with non-specific back pain and postural insufficiencies. The evolutions of these methods aim to standardize measurements and provide manageable tools in clinical practice for the early diagnosis of musculoskeletal pathologies and to monitor daily improvements of each patient. Herein, these devices and their uses are described, providing researchers, clinicians, orthopedics, physical therapists, and sports coaches an effective guide to use new technologies in their practice as instruments of diagnosis, therapy, and prevention.

Lower Limb Kinematics in Individuals with Hip Osteoarthritis during Gait: A Focus on Adaptative Strategies and Interlimb Symmetry

Among the functional limitations associated with hip osteoarthritis (OA), the alteration of gait capabilities represents one of the most invalidating as it may seriously compromise the quality of life of the affected individual. The use of quantitative techniques for human movement analysis has been found valuable in providing accurate and objective measures of kinematics and kinetics of gait in individuals with hip OA, but few studies have reported in-depth analyses of lower limb joint kinematics during gait and, in particular, there is a scarcity of data on interlimb symmetry. Such aspects were investigated in the present study which tested 11 individuals with hip OA (mean age 68.3 years) and 11 healthy controls age- and sex-matched, using 3D computerized gait analysis to perform point-by-point comparisons of the joint angle trends of hip, knee, and ankle. Angle-angle diagrams (cyclograms) were also built to compute several parameters (i.e., cyclogram area and orientation and Trend Symmetry) from which to assess the degree of interlimb symmetry. The results show that individuals with hip OA exhibit peculiar gait patterns characterized by severe modifications of the physiologic trend at hip level even in the unaffected limb (especially during the stance phase), as well as minor (although significant) alterations at knee and ankle level. The symmetry analysis also revealed that the effect of the disease in terms of interlimb coordination is present at knee joint as well as hip, while the ankle joint appears relatively preserved from specific negative effects from this point of view. The availability of data on such kinematic adaptations may be useful in supporting the design of specific rehabilitative strategies during both preoperative and postoperative periods.

Complications, readmission and reoperation rates in one-stage bilateral versus unilateral total hip arthroplasty: a high-volume single center case-control study

The study aimed to assess the safety of one-stage bilateral total hip arthroplasty (THA) compared with unilateral THA. In this retrospective observational case–control study were included patients undergoing unilateral (group 1) and one-stage bilateral (group 2) THA in a high-volume center. The groups were matched for gender, age at surgery, and pre-operative American Society of Anesthesiology score. The following variables were assessed: local and systemic complications, postoperative anemia, 30-day and 1-year readmission and reoperation rates, length of hospital stay, and ambulation time. Group 1 reported a significantly higher rate of local and systemic complications compared with group 2 (5.4% versus 3.9% and 29.6% versus 4.7%, respectively). Postoperative anemia was significantly lower in group 1 compared with group 2 (8.1% versus 30%). There was no significant difference in terms of 30-day and 1-year readmission rates between the two groups. The average length of hospital stay was 5.1 ± 2.3 days in group 1, and 5.3 ± 1.9 days in group 2 (p = 0.78). Ambulation time was significantly lower for group 1 (day 0.9 ± 0.9 in group 1, and day 1 ± 0.8 in group 2, p = 0.03). In a high-volume center, one-stage bilateral THA is a safe procedure compared with unilateral THA in terms of postoperative local and systemic complications, 30-day readmission and 1-year reoperation rates, and length of hospital stay.

Health technology assessment through Six Sigma Methodology to assess cemented and uncemented protheses in total hip arthroplasty

The purpose of this study is to use Health Technology Assessment (HTA) through the Six Sigma (SS) and DMAIC (Define, Measure, Analyse, Improve, Control) problem-solving strategies for comparing cemented and uncemented prostheses in terms of the costs incurred for Total hip arthroplasty (THA) and the length of hospital stay (LOS). Multinomial logistic regression analysis for modelling the data was also performed. Quantitative parameters extracted from gait analysis, electromyography and computed tomography images were used to compare the approaches, but the analysis did not show statistical significance. The variables regarding costs were studied with the Mann-Whitney and Kruskal-Wallis tests. No statistically significant difference between cemented and uncemented prosthesis for the total cost of LOS was found, but the cost of the surgeon had an influence on the overall expenses, affecting the cemented prosthetic approach. The material costs of surgery for the uncemented prosthesis and the cost of theatre of surgery for the cemented prosthesis were the most influential. Multinomial logistic regression identified the Vastus Lateralis variable as statistically significant. The overall accuracy of the model is 93.0%. The use of SS and DMAIC cycle as tools of HTA proved that the cemented and uncemented approaches for THA have similar costs and LOSy.

Machine-Learning Based Determination of Gait Events from Foot-Mounted Inertial Units

A promising but still scarcely explored strategy for the estimation of gait parameters based on inertial sensors involves the adoption of machine learning techniques. However, existing approaches are reliable only for specific conditions, inertial measurements unit (IMU) placement on the body, protocols, or when combined with additional devices. In this paper, we tested an alternative gait-events estimation approach which is fully data-driven and does not rely on a priori models or assumptions. High-frequency (512 Hz) data from a commercial inertial unit were recorded during 500 steps performed by 40 healthy participants. Sensors’ readings were synchronized with a reference ground reaction force system to determine initial/terminal contacts. Then, we extracted a set of features from windowed data labeled according to the reference. Two gray-box approaches were evaluated: (1) classifiers (decision trees) returning the presence of a gait event in each time window and (2) a classifier discriminating between stance and swing phases. Both outputs were submitted to a deterministic algorithm correcting spurious clusters of predictions. The stance vs. swing approach estimated the stride time duration with an average error lower than 20 ms and confidence bounds between ±50 ms. These figures are suitable to detect clinically meaningful differences across different populations.

Dynamic biomechanical effect of lower body positive pressure treadmill training for hemiplegic gait rehabilitation after stroke: A case report

BACKGROUND

Lower body positive pressure (LBPP) treadmill has potential applications for improving the gait of patients after stroke, but the related mechanism remains unclear.

CASE SUMMARY

A 62-year-old male patient suffered from ischemic stroke with hemiplegic gait. He was referred to our hospital because of a complaint of left limb weakness for 2 years. The LBPP training was performed one session per day and six times per week for 2 wk. The dynamic plantar pressure analysis was taken every 2 d. Meanwhile, three-digital gait analysis and synchronous electromyography as well as clinical assessments were taken before and after LBPP intervention and at the 4-wk follow-up. During LBPP training, our patient not only improved his lower limb muscle strength and walking speed, but more importantly, the symmetry index of various biomechanical indicators improved. Moreover, the patient’s planter pressure transferring from the heel area to toe area among the LBPP training process and the symmetry of lower body biomechanical parameters improved.

CONCLUSION

In this study, we documented a dynamic improvement of gait performance in a stroke patient under LBPP training, which included lower limb muscle strength, walking speed, and symmetry of lower limb biomechanics. Our study provides some crucial clues about the potential dynamic mechanism for LBPP training on gait and balance improvement, which is related to rebuilding foot pressure distribution and remodeling symmetry of biomechanics of the lower limb.

Kinematic Gait Analysis After Primary Total Hip Replacement: A Systematic Review: Gait After Total Hip Replacement: A Systematic Review

Total hip replacement (THR) is a surgical procedure indicated for patients affected by severe hip osteoarthritis. Although this technique has proved to be effective in relieving pain and restoring function, gait limitations may persist following this procedure. The objective of this systematic review was to evaluate gait kinematics after THR and compare the results with those of the pre-operative state and with healthy control individuals. PubMed/MEDLINE, Embase, Web of Science, CENTRAL and Scopus databases were searched until December 2019. Methodological quality and internal validity score of each study were assessed using the PEDro and the Newcastle-Ottawa scales. In all, ten studies met our inclusion criteria. Following THR, statistically significant improvements were seen in dynamic hip and knee range of motion of both the affected and the contralateral limb, single-limb support time symmetry, step length, stride length, walking speed and gait pattern. However, deficits were observed in all the previous parameters, as well as in hip adduction angle in comparison with healthy subjects. In conclusion, gait patterns improve after THR in comparison with the pre-operative state, although there are deficits relative to healthy individuals.

3D Tracking of Human Motion Using Visual Skeletonization and Stereoscopic Vision

The design of markerless systems to reconstruct human motion in a timely, unobtrusive and externally valid manner is still an open challenge. Artificial intelligence algorithms based on automatic landmarks identification on video images opened to a new approach, potentially e-viable with low-cost hardware. OpenPose is a library that t using a two-branch convolutional neural network allows for the recognition of skeletons in the scene. Although OpenPose-based solutions are spreading, their metrological performances relative to video setup are still largely unexplored. This paper aimed at validating a two-cameras OpenPose-based markerless system for gait analysis, considering its accuracy relative to three factors: cameras' relative distance, gait direction and video resolution. Two volunteers performed a walking test within a gait analysis laboratory. A marker-based optical motion capture system was taken as a reference. Procedures involved: calibration of the stereoscopic system; acquisition of video recordings, simultaneously with the reference marker-based system; video processing within OpenPose to extract the subject's skeleton; videos synchronization; triangulation of the skeletons in the two videos to obtain the 3D coordinates of the joints. Two set of parameters were considered for the accuracy assessment: errors in trajectory reconstruction and error in selected gait space-temporal parameters (step length, swing and stance time). The lowest error in trajectories (~20 mm) was obtained with cameras 1.8 m apart, highest resolution and straight gait, and the highest (~60 mm) with the 1.0 m, low resolution and diagonal gait configuration. The OpenPose-based system tended to underestimate step length of about 1.5 cm, while no systematic biases were found for swing/stance time. Step length significantly changed according to gait direction (p = 0.008), camera distance (p = 0.020), and resolution (p < 0.001). Among stance and swing times, the lowest errors (0.02 and 0.05 s for stance and swing, respectively) were obtained with the 1 m, highest resolution and straight gait configuration. These findings confirm the feasibility of tracking kinematics and gait parameters of a single subject in a 3D space using two low-cost webcams and the OpenPose engine. In particular, the maximization of cameras distance and video resolution enabled to achieve the highest metrological performances.