Characteristics of Unsuccessful Balance Reactive Responses to Lateral Loss of Balance in Older Adults.

INTRODUCTION: An effective reactive step response to an unexpected balance loss is an important factor that determines if a fall will happen. We investigated reactive step strategies and kinematics of unsuccessful balance recovery responses that ended with falls in older adults. METHODS: We compared the strategies and kinematics of reactive stepping after a lateral loss of balance, i.e., perturbations, between 49 older female adults who were able to successfully recover from perturbations (perturbation-related non-fallers, PNFs) and 10 female older adults who failed to recover (perturbation-related fallers, PFs). In addition, we compared the successful versus unsuccessful recovery responses of PFs matched to perturbation magnitude. RESULTS: The kinematics of the first reactive step response were significantly different between PFs and PNFs, i.e., longer initiation time, step time, swing time, and time to peak swing-leg velocity, larger first-step length, and center-of-mass displacement. Incomplete crossover stepping and leg collision were significant causes of falls among PFs. Similar findings were found when we compared the successful versus unsuccessful recovery responses of PFs. CONCLUSIONS: The crossover step, which requires a complex coordinated leg movement, resulted in difficulty in controlling and decelerating the moving center of mass following a lateral perturbation, affecting the kinematics of the stepping response, leading to a fall.

Subacromial Balloon Spacer for Irreparable Rotator Cuff Tear Treatment Shows Improved Pain and Strength at 5-Year Follow-Up.

PURPOSE: To report on minimum 5-year outcomes following subacromial balloon spacer implantation (SBSI), in terms of survivorship, pain reduction, functional outcomes, complications, and reoperations. METHODS: Data were prospectively collected and retrospectively analyzed for consecutive patients undergoing SBSI between April 1, 2012, and June 30, 2016. Patients completed preoperative and postoperative follow-up for minimum 5 years on the following patient-reported outcomes (PROs): Constant-Murley Score (CMS), visual analog scale for pain (VAS), strength, and patient satisfaction. Reoperations and complications were recorded. Minimal detectable change (MDC) was calculated and the proportion of patients achieving MDC for CMS and VAS were calculated. RESULTS: During the study period, SBSI was performed in 36 patients. Three patients were deceased within 5 years. Of the remaining 33 patients, follow-up was available on 29 patients (80.6%). Mean age at the time of operation was 72.7 ± 4.5 years, and 69% of the patients were males. Mean follow-up time was 72.5 months. Significant improvements from preoperative to last follow-up were demonstrated in CMS (36.08 vs. 63.88; P < .001), VAS (6.72 vs. 1.68; P < .001), and strength (3.8 vs 5.87 kg; P < .001). These improvements were demonstrated at 3 weeks, 6 months, 12 months, 24 months, and 60 months. Mean patient satisfaction at last follow-up was 8.72. The MDC for both CMS and VAS was achieved by 75.9% (22/29) of patients. Four patients underwent conversion to a reverse total shoulder arthroplasty (RTSA). Complications included one patient with balloon dislocation and one patient with a secondary infection due to urinary tract infection. CONCLUSIONS: Pain reduction and functional improvements are sustained at minimum 5 years after SBSI in patients with irreparable rotator cuff tears. The 5-year conversion rate to an RTSA was 13.79%. LEVEL OF EVIDENCE: Level IV, retrospective case-series.

Decrease in incidence of proximal femur fractures in the elderly population during the Covid-19 pandemic: a case-control study.

BACKGROUND: The World Health Organization classified Covid-19 as a pandemic during the first months of 2020 as lockdown measures were implemented globally to mitigate the increasing incidence of Covid-19-related morbidity and mortality. The purpose of this study was to evaluate the effect of national lockdown measures on proximal femur fracture epidemiology. Our hypothesis was that due to the prolonged period of stay-at-home orders, we would observe a decrease in the incidence of proximal femur fractures during the years 2020-21. METHODS: A retrospective case-control study of 2784 hip fractures admitted to the emergency department at one hospital between January 1, 2010, and March 31, 2021, was conducted. Cases were stratified weekly, and an analysis was conducted comparing cases occurring during government-imposed lockdown periods of 2020-21 to corresponding periods during 2010-2019. Furthermore, the trend of cases throughout the year of 2020 was observed. RESULTS: Of all proximal femur fracture cases included, 2522 occurred between 2010-2019 and 261 during the Covid-19 period. There was no significant difference in age (81.95 vs. 82.09; P = 0.78) or gender (P = 0.12). There was a total decrease of 21.64% in proximal femur fracture per week during the entirety of the Covid-19 pandemic period compared to the previous years (3.64 ± 1.99 vs. 4.76 ± 0.83; P = 0.001). During all three lockdown periods, there was a significant decrease in proximal femur fracture cases per week (3.55 ± 2.60 vs. 4.87 ± 0.95; P = 0.04), and the most pronounced decrease occurred during the third lockdown period (2.89 ± 1.96 vs. 5.23 ± 1.18; P = 0.01). CONCLUSION: We observed a total decrease in the number of proximal femur fractures occurring during the Covid-19 era compared to previous years and specifically a decrease of cases occurring during the government-imposed lockdown periods. The decrease in cases was more pronounced during the second and third lockdown periods.

[PROXIMAL FEMUR FRACTURES IN A TERTIARY HOSPITAL DURING THE COVID-19 PANDEMIC].

INTRODUCTION: A larger number of proximal hip fractures occur outdoors rather than within a patient's home. BACKGROUND: At the beginning of 2020, Covid-19 was classified as a global pandemic. Elderly patients are at risk for both occurrences of osteoporotic proximal hip fractures and for increased morbidity and mortality due to infection with Covid-19. Lockdown measures were implemented to decrease the rising incidence of Covid-19. The effect of these measures on hip fracture epidemiology is unknown. OBJECTIVES: This study aimed to evaluate the effect of national lockdown measures on proximal hip fracture epidemiology. METHODS: Data on patients with proximal hip fractures admitted between January 2019 and December 2020 were collected retrospectively. Cases were stratified weekly. Information was compared, between government imposed lockdown periods during 2020, to corresponding periods during 2019. The trend of cases throughout the year 2020 was observed. RESULTS: Of 477 cases included, 259 occurred in 2019 and 218 in 2020. There was no significant difference in age, gender, and primary residence. There was a decrease of 20.45% in proximal hip fracture per week during the entirety of the Covid-19 period compared to 2019 (3.89 ± 2.13 vs. 4.89 ± 2.00; p= 0.02), and a 15.95% decrease during the entire year of 2020 (4.11 ± 2.33 vs. 4.89 ± 1.99; p= 0.07). The most pronounced decrease occurred during the second lockdown period (4.6±1.67 vs. 2.40±1.82; p=0.04). CONCLUSIONS: There was a significant decrease in the number of proximal hip fractures during the Covid-19 pandemic, specifically occurring during the government imposed lockdowns. DISCUSSION: The surrounding environment affects the risk of having a hip fracture in the elderly population, avoiding going out decreases the probability for a femoral neck fracture.

Development and piloting of a perturbation stationary bicycle robotic system that provides unexpected lateral perturbations during bicycling (the PerStBiRo system).

BACKGROUND: Balance control, and specifically balance reactive responses that contribute to maintaining balance when balance is lost unexpectedly, is impaired in older people. This leads to an increased fall risk and injurious falls. Improving balance reactive responses is one of the goals in fall-prevention training programs. Perturbation training during standing or treadmill walking that specifically challenges the balance reactive responses has shown very promising results; however, only older people who are able to perform treadmill walking can participate in these training regimes. Thus, we aimed to develop, build, and pilot a mechatronic Perturbation Stationary Bicycle Robotic system (i.e., PerStBiRo) that can challenge balance while sitting on a stationary bicycle, with the aim of improving balance proactive and reactive control. METHODS: This paper describes the development, and building of the PerStBiRo using stationary bicycles. In addition, we conducted a pilot randomized control trial (RCT) with 13 older people who were allocated to PerStBiRo training (N = 7) versus a control group, riding stationary bicycles (N = 6). The Postural Sway Test, Berg Balance Test (BBS), and 6-min Walk Test were measured before and after 3 months i.e., 20 training sessions. RESULTS: The PerStBiRo System provides programmed controlled unannounced lateral balance perturbations during stationary bicycling. Its software is able to identify a trainee's proactive and reactive balance responses using the Microsoft Kinect™ system. After a perturbation, when identifying a trainee's trunk and arm reactive balance response, the software controls the motor of the PerStBiRo system to stop the perturbation. The pilot RCT shows that, older people who participated in the PerStBiRo training significantly improved the BBS (54 to 56, p = 0.026) and Postural Sway velocity (20.3 m/s to 18.3 m/s, p = 0.018), while control group subject did not (51.0 vs. 50.5, p = 0.581 and 15 m/s vs. 13.8 m/s, p = 0.893, respectively), 6MWT tended to improve in both groups. CONCLUSIONS: Our participants were able to perform correct balance proactive and reactive responses, indicating that older people are able to learn balance trunk and arm reactive responses during stationary bicycling. The pilot study shows that these improvements in balance proactive and reactive responses are generalized to performance-based measures of balance (BBS and Postural Sway measures).

Acetabular cup orientation and postoperative leg length discrepancy in patients undergoing elective total hip arthroplasty via a direct anterior and anterolateral approaches.

BACKGROUND: Total hip arthroplasty (THA) is considered a successful surgical procedure. It can be performed by several surgical approaches. Although the posterior and anterolateral approaches are the most common, there has been increased interest in the direct anterior approach. The goal of the present study is to compare postoperative leg length discrepancy and acetabular cup orientation among patients who underwent total hip arthroplasty through a direct anterior (DAA) and anterolateral (ALA) approaches. METHODS: The study included 172 patients undergoing an elective THA by a single surgeon at our institution within the study period. Ninety-eight arthroplasties were performed through the ALA and 74 arthroplasties through the DAA. Preoperative planning was performed for all patients. Assessment of the two groups included the following postoperative parameters: abduction angle, cup anteversion angle and leg length discrepancy (LLD). Additional analysis was done to evaluate component positioning by comparing deviation from the Lewinnek zone of safety in both approaches. RESULTS: For the DAA the absolute LLD was 11 mm, ranging from -6 mm to 5 mm. For the ALA, the absolute LLD was 36 mm, ranging from -22 mm to 14 mm. None of the DAA patients had an absolute LLD greater than 6 mm. Comparatively, 7.4% of the ALA group exceeded 6 mm of LLD in addition to 2.1% with LLD greater than 10 mm. 15% of the ALA group resided out of the Lewinnek abduction zone compared to 3% of the DAA group (P = 0.016). 17% of the ALA group were out of the Lewinnek anteversion zone as opposed to 8% of the DAA group (P = 0.094). CONCLUSION: Our study demonstrates good component positioning outcomes and LLD values in patients following THA through the DAA compared to the ALA.

Radiographic templating of total hip arthroplasty for femoral neck fractures.

PURPOSE: The purpose of this study was to evaluate the use of pre-operative digital templating to minimize complications including limb length discrepancy (LLD), intraoperative fractures and early dislocations in patients with intracapsular femoral neck fractures. METHODS: We retrospectively compared 23 patients undergoing total hip arthroplasty (THA) for intracapsular femoral fractures with pre-operative digital templating and 48 patients without templating. RESULTS: The mean post-operative LLD was significantly lower in patients who had pre-operative templating than in the control group (6.7 vs. 11.5 mm, p = 0.023). Only three patients (13 %) with templating had LLD greater than 1.5 cm, compared to the 15 patients (31 %) without templating (p = 0.17). In eight cases the final femoral stem size matched the templated size, while 19 patients were within two size increments. Complications included one dislocation and one intra-operative fracture in the control group. CONCLUSION: The present study demonstrated that careful pre-operative planning may reduce LLD in patients undergoing THA due to intracapsular hip fractures.

Reverse total shoulder replacement for patients with "weight-bearing" shoulders.

BACKGROUND: Reverse total shoulder arthroplasty (rTSA) has gained popularity in recent years and is indicated for a wide variety of shoulder pathologies. However, use of rTSA in patients with "weight-bearing" shoulders that support wheelchair use or crutches has higher risk. The aim of this study was to assess the results of rTSA in such patients. METHODS: Between 2005 and 2014, 24 patients (30 shoulders) with weight-bearing shoulders were treated with rTSA at our unit. Patients had cuff arthropathy (n=21), rheumatoid arthritis (n=3), osteoarthritis (n=1), acute fracture (n=3), or fracture sequela (n=2). Postoperatively, patients were advised not to push themselves up and out of their wheelchair for 6 weeks. This study was performed in 2016, and 21 patients (27 shoulders) were available for a mean follow-up of 5.6 years (range, 2-10 years). The mean age at surgery was 78 years (range, 54-90 years). RESULTS: Constant-Murley score improved from 9.4 preoperatively to 59.8 at the final follow-up (P=0.001). Pain score improved from 2/15 to 13.8/15 (P=0.001). Patient satisfaction (Subjective Shoulder Value) improved from 0.6/10 to 8.7/10 (P=0.001). Significant improvement in mean range of motion from 46° to 130° of elevation, 14° to 35° of external rotation, and 29° to 78° internal rotation was recorded (P=0.001). Final mean Activities of Daily Living External and Internal Rotation was 32.4/36. Only three patients showed Sirveaux-Nerot grade-1 (10%) glenoid notching and three grade 2 (10%). CONCLUSIONS: rTSA can be used for treatment of patients with weight-bearing shoulders. Such patients reported pain free movement, resumed daily activities, and high satisfaction rates. Level of evidence: IV.

Responses From ChatGPT-4 Show Limited Correlation With Expert Consensus Statement on Anterior Shoulder Instability.

Purpose: To compare the similarity of answers provided by Generative Pretrained Transformer-4 (GPT-4) with those of a consensus statement on diagnosis, nonoperative management, and Bankart repair in anterior shoulder instability (ASI). Methods: An expert consensus statement on ASI published by Hurley et al. in 2022 was reviewed and questions laid out to the expert panel were extracted. GPT-4, the subscription version of ChatGPT, was queried using the same set of questions. Answers provided by GPT-4 were compared with those of the expert panel and subjectively rated for similarity by 2 experienced shoulder surgeons. GPT-4 was then used to rate the similarity of its own responses to the consensus statement, classifying them as low, medium, or high. Rates of similarity as classified by the shoulder surgeons and GPT-4 were then compared and interobserver reliability calculated using weighted κ scores. Results: The degree of similarity between responses of GPT-4 and the ASI consensus statement, as defined by shoulder surgeons, was high in 25.8%, medium in 45.2%, and low 29% of questions. GPT-4 assessed similarity as high in 48.3%, medium in 41.9%, and low 9.7% of questions. Surgeons and GPT-4 reached consensus on the classification of 18 questions (58.1%) and disagreement on 13 questions (41.9%). Conclusions: The responses generated by artificial intelligence exhibit limited correlation with an expert statement on the diagnosis and treatment of ASI. Clinical Relevance: As the use of artificial intelligence becomes more prevalent, it is important to understand how closely information resembles content produced by human authors.

Subchondral bone density distribution in the human femoral head.

OBJECTIVE: This study aims to quantitatively characterize the distribution of subchondral bone density across the human femoral head using a computed tomography derived measurement of bone density and a common reference coordinate system. MATERIALS AND METHODS: Femoral head surfaces were created bilaterally for 30 patients (14 males, 16 females, mean age 67.2 years) through semi-automatic segmentation of reconstructed CT data and used to map bone density, by shrinking them into the subchondral bone and averaging the greyscale values (linearly related to bone density) within 5 mm of the articular surface. Density maps were then oriented with the center of the head at the origin, the femoral mechanical axis (FMA) aligned with the vertical, and the posterior condylar axis (PCA) aligned with the horizontal. Twelve regions were created by dividing the density maps into three concentric rings at increments of 30° from the horizontal, then splitting into four quadrants along the anterior-posterior and medial-lateral axes. Mean values for each region were compared using repeated measures ANOVA and a Bonferroni post hoc test, and side-to-side correlations were analyzed using a Pearson's correlation. RESULTS: The regions representing the medial side of the femoral head's superior portion were found to have significantly higher densities compared to other regions (p < 0.05). Significant side-to-side correlations were found for all regions (r(2) = 0.81 to r(2) = 0.16), with strong correlations for the highest density regions. Side-to-side differences in measured bone density were seen for two regions in the anterio-lateral portion of the femoral head (p < 0.05). CONCLUSIONS: The high correlation found between the left and right sides indicates that this tool may be useful for understanding 'normal' density patterns in hips affected by unilateral pathologies such as avascular necrosis, fracture, developmental dysplasia of the hip, Perthes disease, and slipped capital femoral head epiphysis.

Functional and anatomic orientation of the femoral head.

BACKGROUND: Femoral neck geometry directly affects load transmission through the hip. Orientations may be described anatomically or using functional definitions that consider load transmission. QUESTIONS/PURPOSES: This study introduces and applies a new method for characterizing functional femoral orientation based on the distribution of subchondral bone density in the femoral head and compares it with orientation measures generated via established anatomic landmark-based methods. Both orientation methods then are used to characterize side-to-side symmetry of orientation and differences between men and women within the population. PATIENTS AND METHODS: A retrospective review of CT imaging data from 28 patients was performed. Anatomic orientation was determined using established two-dimensional and three-dimensional landmarking methods. Subchondral bone density maps were generated and used to define a density-weighted surface normal vector. Orientation angles generated by the three methods were compared, with side-to-side symmetry and differences between genders also investigated. RESULTS: The three methods measured substantially different angles for anteversion and neck-shaft angle. Weak correlations were found between anatomic and functional orientation measures for neck-shaft angle only. CONCLUSIONS: Neck-shaft angles calculated using the functional orientation method corresponded well with previous in vivo loading data. An absence of strong correlation between functional and anatomic measures reinforces the concept that bone geometry is not solely responsible for determining loading of the femoral head. LEVEL OF EVIDENCE: Level II, Diagnostic Studies--Investigating a Diagnostic Test. See the Guidelines for Authors for a complete description of levels of evidence.

The effect of a preoperative physical therapy education program on short-term outcomes of patients undergoing elective total hip arthroplasty: A controlled prospective clinical trial.

OBJECTIVE: The aim of this study was to determine the effect of a preoperative physical therapy education program on the shortterm outcomes of patients undergoing elective Total Hip Arthroplasty (THA). METHODS: A prospective, parallel-group controlled clinical trial was conducted from September 2016 to July 2018. Fifty patients who were scheduled for a first elective THA procedure were recruited and were equally allocated into one of two groups: intervention and control groups. While all patients received the routine preparation for the procedure, the intervention group underwent an additional structured physical therapy education session. Functional status was evaluated using The Oxford Hip Score (OHS) preoperatively and 6 weeks after the operation. Length of Hospital Stay (LOS) was recorded. State anxiety was measured by the state-anxiety portion of the Spielberger's State-Trait Anxiety Inventory questionnaire preoperatively and on the second postoperative day. Gait and balance abilities were assessed using Tinetti Performance-Oriented Mobility Assessment (POMA) test on the second postoperative day. Pain at rest and during weight-bearing was measured by a Numerical Rating Scale (NRS) on the postoperative second day. Satisfaction rates were evaluated by the NRS 6 weeks after the operation. RESULTS: Forty-seven patients completed the study. The intervention group consisted of 24 patients (10 males, 14 females; mean age = 64.29 ± 6.7 years), and the control group consisted of 23 patients (7 males, 16 females; mean age = 65.91 ± 10.19 years). The mean postoperative OHS was significantly higher in the intervention group than in the control group (39.04 ± 3.99 vs 28.04 ± 7.23, P < 0.001). Both groups increased their functional abilities 6 weeks postoperatively; however, the intervention group showed a greater increase than the control group (P = 0.001). No significant difference was found in the LOS between the control (2.83 ± 0.71) and intervention groups (2.71 ± 0.62) (P = 0.551). Patients in the intervention group exhibited lower rates of anxiety two days after the operation compared with the controls (17.75 ± 6.50 vs 27.70 ± 10.32, P < 0.001). The intervention group showed higher postoperative POMA scores compared to the control group (19.67 ± 3.89 vs 15.39 ± 5.85, P = 0.005). Although no significant difference was observed in resting pain between groups (P = 0.105), the intervention group reported a lower pain intensity while walking compared to the control group (5.04 ± 1.68 vs 6.39 ± 2.62, P = 0.041). While both groups reported high satisfaction rates 6 weeks postoperatively, patients in the intervention group were more satisfied than those in the control group (9.67 ± 0.91 vs 8.35 ± 1.82, P = 0.003). CONCLUSION: A structured interactive preoperative physical therapy education program for patients undergoing a THA may reduce anxiety, generate a faster recovery, reduce pain, and promote higher satisfaction. We recommend this program for routine use. LEVEL OF EVIDENCE: Level II, Therapeutic Study.

Pain Pharmacotherapy in a Large Cohort of Patients with Osteoarthritis: A Real-World Data Analysis.

INTRODUCTION: There is limited evidence on the consumption of analgesics in real-world large cohorts of patients with osteoarthritis (OA), especially in those with comorbidities. We aimed to characterize the use of pharmacological analgesic treatments, evaluate standardized comorbidity rates, and assess treatment trends. Our hypotheses were: (1) OA patients generally consume low and inconsistent pharmacological analgesic treatments; (2) analgesic treatment is often non-congruent with comorbidity-related safety concerns. METHODS: The study was carried out at the second largest health maintenance organization in Israel. Members aged 18 years or above who were diagnosed with OA before December 31, 2018, were included. Information was obtained from the members' electronic medical record (EMR) including data on dispensed prescriptions, which were used to estimate analgesic consumption. RESULTS: A total of 180,126 OA patients were included in our analyses; analgesics were dispensed to 64.2% of the patients, with oral NSAIDs and opioids dispensed to 34.1 and 22.9% of the OA population, respectively. Analgesic use increased with time lapsed from OA diagnosis (p < 0.001), up to a median of 59 days covered (IQR, 20-175) after 21 years. Rates of most comorbidities in the OA population were higher compared to the MHS general population. Patients with comorbidities used more NSAIDs and opioids compared to those without them. CONCLUSIONS: Most OA patients use analgesics, usually oral NSAIDs. Analgesic use remains relatively low throughout the years, indicating that many OA patients are not being treated pharmacologically for pain on a regular basis. Despite having higher rates of several comorbidities compared to MHS general population, many OA patients are still treated with analgesics that can be associated with a worsening in comorbidity.

Prevalence and Incidence of Osteoarthritis: A Population-Based Retrospective Cohort Study.

While trends data of osteoarthritis (OA) are accumulating, primarily from Western Europe and the US, a gap persists in the knowledge of OA epidemiology in Middle Eastern populations. This study aimed to explore the prevalence, incidence, correlations, and temporal trends of OA in Israel during 2013-2018, using a nationally representative primary care database. On 31 December 2018, a total of 180,126 OA patients were identified, representing a point prevalence of 115.3 per 1000 persons (95% CI, 114.8-115.8 per 1000 persons). Geographically, OA prevalence was not uniformly distributed, with the Southern and Northern peripheral districts having a higher prevalence than the rest of the Israeli regions. OA incidence increased over time from 7.36 per 1000 persons (95% CI 6.21-7.50 per 1000 persons) in 2013 to 8.23 per 1000 persons (95% CI 8.09-8.38 per 1000 persons) in 2017 (p-value for trend = 0.02). The incidence was lowest in patients under 60 years (in both sexes) and peaked at 60-70 years. In older ages, the incidence leveled off in men and declined in women. The growing risk of OA warrants a greater attention to timely preventive and therapeutic interventions. Further population-based studies in the Middle East are needed to identify modifiable risk factors for timely preventive and therapeutic interventions.

The Effects of Bicycle Simulator Training on Anticipatory and Compensatory Postural Control in Older Adults: Study Protocol for a Single-Blind Randomized Controlled Trial.

Background: Falls are the leading cause of fatal and non-fatal injuries among older adults. Perturbation-Based-Balance Training (PBBT) is a promising approach to reduce fall rates by improving reactive balance responses. PBBT programs are designed for older adults who are able to stand and walk on a motorized treadmill independently. However, frail older adults, whose fall rates are higher, may not have this ability and they cannot participate. Thus, there is a critical need for innovative perturbation exercise programs to improve reactive balance and reduce the fall risks among older adults in a wider range of functioning. Trunk and arms are highly involved in reactive balance reactions. We aim to investigate whether an alternative PBBT program that provides perturbations during hands-free bicycling in a sitting position, geared to improve trunk and arm reactive responses, can be transferred to reduce fall risks and improve balance function among pre-frail older adults. Methods: In a single-blinded randomized-controlled trial, 68 community-dwelling pre-frail older adults are randomly allocated into two intervention groups. The experimental group receives 24-PBBT sessions over 12-weeks that include self-induced internal and machine-induced external unannounced perturbations of balance during hands-free pedaling on a bicycle-simulator system, in combination with cognitive dual-tasks. The control group receives 24 pedaling sessions over 12-weeks by the same bicycle-simulator system under the same cognitive dual-tasks, but without balance perturbations. Participants' reactive and proactive balance functions and gait function are assessed before and after the 12-week intervention period (e.g., balance reactive responses and strategies, voluntary step execution test, postural stability in upright standing, Berg Balance Test, Six-meter walk test, as well as late life function and fear of falling questionnaires). Discussion: This research addresses two key issues in relation to balance re-training: (1) generalization of balance skills acquired through exposure to postural perturbations in a sitting position investigating the ability of pre-frail older adults to improve reactive and proactive balance responses in standing and walking, and (2) the individualization of perturbation training to older adults' neuromotor capacities in order to optimize training responses and their applicability to real-life challenges. Clinical Trial Registration: www.clinicaltrials.gov, NCT03636672 / BARZI0104; Registered: July 22, 2018; Enrolment of the first participant March: 1, 2019. See Supplementary File.

Patient-specific finite element analysis of femurs with cemented hip implants.

BACKGROUND: Over 1.6 million hip replacements are performed annually in Organisation for Economic Cooperation and Development countries, half of which involve cemented implants. Quantitative computer tomography based finite element methods may be used to assess the change in strain field in a femur following such a hip replacement, and thus determine a patient-specific optimal implant. A combined experimental-computational study on fresh frozen human femurs with different cemented implants is documented, aimed at verifying and validating the methods. METHODS: Ex-vivo experiments on four fresh-frozen human femurs were conducted. Femurs were scanned, fractured in a stance position loading, and thereafter implanted with four different prostheses. All femurs were reloaded in stance positions at three different inclination angles while recording strains on bones' and prosthesis' surfaces. High-order FE models of the intact and implanted femurs were generated based on the computer tomography scans and X-ray radiographs. The models were virtually loaded mimicking the experimental conditions and FE results were compared to experimental observations. FINDINGS: Strains predicted by finite element analyses in all four femurs were in excellent correlation with experimental observations FE = 1.01 × EXP - 0.07,R2 = 0.976, independent of implant's type, loading angle and fracture location. INTERPRETATION: Computer tomography based finite element models can reliably determine strains on femur surface and on inserted implants at the contact with the cement. This allows to investigate suitable norms to rank implants for a patient-specific femur so to minimize changes in strain patterns in the operated femur.

Proximal Femoral Shortening After Cephalomedullary Nail Insertion for Intertrochanteric Fractures.

OBJECTIVE: To assess the incidence of proximal femoral shortening (PFS) and its effect on the patient outcomes when intertrochanteric fractures were treated with a cephalomedullary nail (CMN). DESIGN: Retrospective cohort study. SETTINGS: Level II trauma center. PATIENTS: Forty-eight consecutive patients with OTA/AO 31-A intertrochanteric fractures. INTERVENTION: All patients were treated with a Gamma3 CMN (Stryker, Kalamazoo, MI). METHODS: PFS was assessed for abductor lever arm (x vector), femoral height (y vector), and overall shortening (z vector) on anteroposterior radiographs. Fixation success and retained ambulatory capacity were noted. RESULTS: Shortening of >5 mm of the x, y, and z vectors was evident in 18, 20, and 29 patients, respectively. Shortening of >10 mm of the x, y, and z vectors was measured in 5, 6, and 8 patients, respectively. Mean shortening of the x, y, and z vectors was 4.5, 5.5, and 7 mm, respectively. Greater PFS was found to be associated with fixation failure and inability to retain ambulatory capacity, independently (P ≤ 0.05 and P ≤ 0.025, respectively). Of note, an unstable fracture pattern was not found to be associated with greater PFS. CONCLUSIONS: PFS is a common phenomenon after CMN of intertrochanteric fractures with a Gamma CMN. In addition, greater PFS seems to be associated with fixation failure and inability to retain ambulatory capacity postoperatively. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Correlation between gait analysis and clinical questionnaires in patients with spontaneous osteonecrosis of the knee.

BACKGROUND: Spontaneous osteonecrosis of the knee is usually verified by magnetic resonance imaging accompanied by clinical questionnaires to assess the level of pain and functional limitation. There is a lack however, in an objective functional test that will reflect the functional severity of spontaneous osteonecrosis of the knee. The purpose of the current study was to examine the correlation between spatiotemporal gait parameters and clinical questionnaires in patients with spontaneous osteonecrosis of the knee. METHODS: 28 patients (16 females and 12 males) were included in the analysis. Patients had unilateral spontaneous osteonecrosis of the knee of the medial femoral condyle confirmed by magnetic resonance imaging. All patients performed a computerized spatiotemporal gait analysis and completed the Western Ontario and McMaster University Osteoarthritis Index and the Short-Form 36. Relationships between selected spatiotemporal gait measures and self-assessment questionnaires were assessed by Spearman non-parametric correlations. FINDINGS: Significant correlations were found between selected spatiotemporal gait parameters and clinical questionnaires (r ranged between 0.28 and 0.79). Single limb support was the gait measure with the strongest correlation to pain (r=0.58), function (r=0.56) and quality of life. INTERPRETATION: Spatiotemporal gait assessment for patients with spontaneous osteonecrosis of the knee correlates with the patient's level of pain and functional limitation there by adding objective information regarding the functional condition of these patients.

A novel self-care biomechanical treatment for obese patients with knee osteoarthritis.

AIM: To examine the effect of a novel biomechanical, home-based, gait training device on gait patterns of obese individuals with knee OA. METHODS: This was a retrospective analysis of 105 (32 males, 73 females) obese (body mass index > 30 kg/m2 ) subjects with knee OA who completed a 12-month program using a biomechanical gait training device and performing specified exercises. They underwent a computerized gait test to characterize spatiotemporal parameters, and completed the Western Ontario and McMaster Osteoarthritis Index (WOMAC) questionnaire and Short Form-36 (SF-36) Health Survey. They were then fitted with biomechanical gait training devices and began a home-based exercise program. Gait patterns and clinical symptoms were assessed after 3 and 12 months of therapy. RESULTS: Each gait parameter improved significantly at 3 months and more so at 12 months (P = 0.03 overall). Gait velocity increased by 11.8% and by 16.1%, respectively. Single limb support of the more symptomatic knee increased by 2.5% and by 3.6%, respectively. There was a significant reduction in pain, stiffness and functional limitation at 3 months (P < 0.001 for each) that further improved at 12 months. Pain decreased by 34.7% and by 45.7%, respectively. Functional limitation decreased by 35.0% and by 44.7%, respectively. Both the Physical and Mental Scales of the SF-36 increased significantly (P < 0.001) at 3 months and more so following 12 months. CONCLUSIONS: Obese subjects with knee OA who complied with a home-based exercise program using a biomechanical gait training device demonstrated a significant improvement in gait patterns and clinical symptoms after 3 months, followed by an additional improvement after 12 months.

Arthroscopic trans-portal deep medial collateral ligament pie-crusting release.

Arthroscopic treatments of meniscal injuries of the knee are among the most common orthopaedic procedures performed. Adequate visualization of the posterior horn of the medial meniscus might be challenging, especially in patients with tight medial compartments. In these cases instrument manipulation in an attempt to reach the posterior horn of the meniscus can cause an iatrogenic chondral injury because of the narrow medial joint space. A transcutaneous medial collateral ligament (MCL) pie-crusting release facilitates expansion of the medial joint space in a case of a tight medial compartment. Nevertheless, it might cause injury to the superficial MCL, infection, and pain and injury to the saphenous nerve because of multiple needle punctures of the skin. We describe an inside-out, arthroscopic deep MCL pie-crusting release, which allows access to the medial meniscus through the anterior approach to provide good visualization of the footprint and sufficient working space.