Simple Mobility Tests Predict Use of Assistive Devices in Older Adults.

BACKGROUND: Assistive devices (ADs) for ambulation are commonly provided to improve safety and independence in older adults. Despite the common use of these devices, there are no standard prescribing guidelines, and non-health care providers, including caregivers and family members, often make decisions about the need for ADs. Identifying factors or a single screening test associated with AD use would benefit clinicians and non-health care caregivers in making decisions to adopt an AD for patients, clients, and family members. PURPOSE/OBJECTIVES: The purpose of this cross-sectional study was to identify the test that best predicts ADs for ambulation and non-AD use among community-dwelling individuals. METHODS: Eighty-five older adults (81.6 ± 8.2 years old) who underwent outpatient physical therapy participated in this study. They participated in a series of tests, including the Timed Up and Go, handgrip and quadriceps strength, the 30-second chair-rise test, the 5-m fast gait speed, the Functional Independence Measure, the locomotive syndrome tests (stand-up test, 2-step test [2ST], and the Locomo-5 Checklist), and numeric pain scales. Mann-Whitney U tests were used to identify differences between those who did and did not use an AD for ambulation. Logistic regression analyses were used to examine which test best predicted AD use. RESULTS: 80% of participants (n = 68) used an AD for ambulation. There were significant differences in all test variables between users and nonusers (P = .033 to P < .001), except for quadriceps strength, age, and pain (all P > .05). Only the 2ST was a significant predictor of AD use, with a cutoff distance of the toe-to-toe stride shorter than 93% of body height (sensitivity: 72%, and specificity: 82%, P = .048). DISCUSSION: Simple functional measures differed between those who did and did not use ADs for ambulation; however, only the 2ST predicted AD status. Individuals who cannot step 93% of their body height may be appropriate for an AD. CONCLUSIONS: If comprehensive clinical evaluations are not available to make decisions about AD use, the 2ST can be used to make clinical recommendations for an AD for ambulation.

Factors Related to Expectations in Individuals Waiting for Total Knee Arthroplasty.

Purpose: There is no consensus on how age and expectations influence planning for total knee arthroplasty (TKA). This study developed and evaluated a new expectation questionnaire and assessed the relationship between preoperative expectations and patient characteristics. Method: The questionnaire evaluated expectations for mobility, pain, participation, and rate of recovery after surgery. Fifty-five participants completed a 6-minute walk test and expectation questionnaire prior to TKA; 17 participants repeated the questionnaire one week later for reliability testing. Analysis of the questionnaire included intra-class correlation coefficient (ICC), homoscedasticity, skewness, kurtosis, multicollinearity, and descriptive measures. A four-step hierarchical linear regression was completed to determine the relationship of patient age, BMI, previous contralateral TKA, and 6-minute walk test scores to expectations. Results: The questionnaire showed good/high test-retest reliability (ICC 0.84; 95% CI: 0.57, 0.94; p > 0.001). The final model was significant in predicting expectation scores R2 = 0.19 (p = 0.017). Conclusions: This questionnaire reliably measures patient expectations before TKA; however, further research is needed. Although we anticipated younger age to be related to higher expectations, higher function prior to TKA appears to be more strongly associated with higher expectations.

Objectif: il n'y a pas de consensus quant à l'influence de l'âge et des attentes sur la planification d'une arthroplastie totale du genou (ATG). La présente étude a porté sur l'élaboration et l'évaluation d'un nouveau questionnaire des attentes et a évalué le lien entre les attentes préopératoires et les caractéristiques des patients. Méthodologie: le questionnaire évaluait les attentes en matière de mobilité, de douleur, de participation et de taux de rétablissement après l'opération. Au total, 55 patients ont effectué un test de marche de six minutes et ont rempli un questionnaire sur leurs attentes avant l'ATG; 17 participants ont rempli de nouveau le questionnaire une semaine plus tard en vue d'un test de fiabilité. L'analyse du questionnaire incluait le coefficient de corrélation intraclasse (CCI), l'homoscédasticité, l'asymétrie, la multicolinéarité et des mesures descriptives. Une régression linéaire hiérarchique en quatre étapes a permis de déterminer la relation entre, d'une part, l'âge des patients, leur indice de masse corporelle, leur ATG contralatérale antérieure et les scores de marche de six minutes et, d'autre part, les attentes. Résultats: le questionnaire avait une fiabilité test-retest bonne à élevée (CCI de 0,84, IC à 95 % de 0,57 à 0,94; p > 0,001). Le modèle définitif pouvait prédire de manière significative les scores d'attentes de R2 = 0,19 (p = 0,017). Conclusions: le présent questionnaire mesure avec fiabilité les attentes des patients avant l'ATG, mais d'autres recherches s'imposent. Les chercheurs croyaient qu'un plus jeune âge serait associé à des attentes plus élevées, mais un meilleur fonctionnement avant l'ATG semblait être lié davantage à des hautes attentes.

Concurrent Validity Between Potential Screening Tests for Early Mobility Decline in Independent Community Dwellers.

BACKGROUND AND PURPOSE: Standardized screening tests that detect early mobility decline, regardless of etiology, are needed for healthy aging. The locomotive syndrome (LS) tests are designed to identify stages of mobility decline and inform appropriate levels of intervention. The long-term goal of this research is to develop standardized mobility screening tests that can be used across health care settings and throughout a patient's lifespan to guide appropriate medical care. As the first step in this process, this study examines the concurrent validity between the reference and the LS tests. METHODS: This cross-sectional study examined correlations between the LS functional tests and a set of reference tests and the ability to differentiate the 3 stages of mobility decline. The reference tests included the stair-climbing test, the 30-second chair rise test, the 6-minute walk test, the Global Physical Health (GPH) portion of the PROMIS, and the Lower Extremity Functional Scale (LEFS). The LS tests included the Stand-Up Test, the 2-Step Test, and the 25-question Geriatric Locomotive Function Scale (25-GLFS). A total of 115 community dwellers of 61.2 years old on average (±10.0 years), with n = 71 (61%) older than 60 years, voluntary participated in this prospective study. Nonparametric analyses of variance and correlations were used to examine the concurrent validity. RESULTS AND DISCUSSION: Performance-based tests were significantly correlated (| r | = 0.38-0.61, P < .001) with LS tests. The LEFS was correlated with all LS tests, but the GPH was only correlated with the 25-GLFS. Also, significant differences were found in reference test scores between the 3 LS stages ( P < .05). CONCLUSIONS: The LS tests and reference tests demonstrated significant correlations, and participants performed significantly worse on reference tests as LS severity increased. Given these results, it is possible that the LS standardized tests may play an important role in mobility screening. Future research should investigate feasibility, sensitivity, and specificity of these tests.

Knee biomechanics and contralateral knee osteoarthritis progression after total knee arthroplasty.

BACKGROUND: Despite the success rate of Total Knee Arthroplasty (TKA), many patients undergo contralateral TKA. It is possible that altered gait mechanics after unilateral TKA play a role in the progression of contralateral OA progression. RESEARCH QUESTION: The purpose of this study was to identify biomechanical predictors of radiographic OA progression in the contralateral (non-surgical) knee after unilateral (primary/initial) TKA. In addition, this study quantified for patients who had contralateral OA progression. METHODS: Biomechanical outcomes were collected 6-24 months after unilateral primary TKA and were used to predict changes in contralateral OA severity at follow-up. Participants were divided into "Progressor" and "Non-Progressor" groups based on changes in Kellgren-Lawrence (KL) OA grade and Joint Space Width (JSW) between baseline and follow-up testing sessions. Biomechanical factors during walking were peak knee adduction moment, knee flexion/extension excursions, knee angle at initial foot contact, and peak knee flexion/extension. Multiple independent t-tests were used to examine the magnitude of differences in biomechanical variables between the groups. Logistic regression was used to examine the association between the biomechanical predictors and change in KL scores and JSW. RESULTS: The mean time between surgery and follow-up x-rays was 8.8 (2.4) years. Of 40 participants, 62.5-78% had contralateral radiographic knee OA progression by follow-up. There were no significant differences in the biomechanical variables between groups. For the regression analysis, none of the biomechanical variables were found to be predictors for contralateral OA progression. SIGNIFICANCE: Although abnormal biomechanics are known risk factors for primary knee OA, it is possible that the mechanisms that result in OA progression of the contralateral limb are different than primary knee OA progression. Future work should evaluate other objective measures of OA progression and determine if cumulative measures of joint loading are related to OA worsening.

Falling risk in patients with end-stage knee osteoarthritis.

Although 25% of patients with end-stage knee osteoarthritis (OA) have reported a fall, there is limited information about risk factors for falling in patients awaiting total knee arthroplasty (TKA). The purpose of this study was to identify clinical and functional measures related to fall risk. A total of 259 participants awaiting TKA for OA participated in this secondary cross-sectional study. Participants were divided into fallers and non-fallers based on falling history in the prior 6 months. Clinical measures (hip and knee pain, neck and low back pain (LBP), knee range of motion, and quadriceps strength) and functional measures (six-minute walk test (6MWT), timed up and go test, and Knee Injury and Osteoarthritis Outcome Score (KOOS)) were assessed in patients 2-4 weeks prior to TKA. Independent t tests were used to examine differences between groups. Odds ratio was calculated to identify clinical risk factors for falling. Of all participants, 47 (18%) reported a fall in the previous 6 months. Fallers had 30% greater LBP (3.0 ± 2.5 vs. 2.1 ± 2.6; p = 0.025). Fallers walked 12% shorter distance in the 6MWT than non-fallers (378 ± 100 vs. 422 ± 105 m; p = 0.010). For every 1-point increase in LBP on a 0-10 scale, there was a 14% greater risk of falling (p = 0.028). For every 10-m increase in 6MWT, there was a 3.8% reduction in fall risk (p = 0.011). Greater LBP and worse walking endurance are associated with falls in individuals with end-stage OA. Future studies should determine if interventions that reduce LBP and improve walking performance also reduce the chance of falling.

Gait mechanics are influenced by quadriceps strength, age, and sex after total knee arthroplasty.

Although most patients are satisfied with outcomes after total knee arthroplasty (TKA), many retain preoperative altered gait mechanics. Identifying patient characteristics associated with gait mechanics will improve rehabilitation strategies and enhance our understanding of movement disorders. Therefore, the purpose of this study was to identify which patient characteristics are related to gait mechanics in the surgical limb during walking post-TKA. Patient characteristics included age, body mass, sex, quadriceps strength, self-reported function, and knee pain. General linear regression was used to compare patient characteristics associated with gait mechanics, after controlling for gait speed, functional capacity and time from surgery. We tested 191 patients cross-sectionally at 6-24 months after primary, unilateral TKA. Quadriceps weakness in the surgical limb was associated with less peak vertical ground reaction force (PvGRF) (ß = .245, p = .044), knee extension moment (ß = .283, p = .049), and knee extension excursion (ß = .298, p = .038). Older age (ß = .168, p = .050) was associated with less PvGRF. Quadriceps strength in the nonsurgical limb (ß = -.357, p = .021) was associated with greater knee extension excursion in the surgical limb. Females with TKA (ß = -.276, p = .007) had less knee flexion excursion compared to males. Faster gait speed was also associated with greater PvGRF (ß = .585, p < .001), knee extensor moment (ß = .481, p < .001), and knee flexion excursion (ß = .318, p < .001). Statement of Clinical Significance: This study showed quadriceps weakness, slower gait speed, older age and being female were related to altered gait mechanics post-TKA. These findings will help clinicians better educate patients and develop targeted interventions for improving care in patients post-TKA.

Self-Reported and Performance-Based Outcome Measures Estimation Using Wearables After Unilateral Total Knee Arthroplasty.

Total knee arthroplasty is a common surgical treatment to improve ambulatory function for individuals with end-stage osteoarthritis of the knee. Functional and self-reported measures are widely used to assess functional ability and impairment before and after total knee arthroplasty. However, clinical assessments have limitations and often provide subjective and limited information. Seamless gait characteristic monitoring in the real-world condition is a viable alternative to address these limitations, but the effectiveness of using wearable sensors for knee treatment is unclear. The purpose of this study was to determine if inertial gait variables from wearable sensors effectively estimate the questionnaire, performance (6-min walk test, timed up and go, and 30-s chair stand test), and isometric measure outcomes in individuals after unilateral total knee arthroplasty. Eighteen subjects at least 6 months post-surgery participated in the experiment. In one session, three tasks, including self-reported surveys, functional testing, and isometric tests were conducted. In another session, the participants' gait patterns were measured during a 1-min walking test at their self-selected gait speed with two accelerometers worn above the lateral malleoli. Session order was inconsistent between subjects. Significant inertial gait variables were selected using stepwise regressions, and the contributions of different categories of inertial gait variables were examined using hierarchical regressions. Our results indicate inertial gait variables were significantly correlated with performance test and questionnaire outcomes but did not correlate well with isometric strength measures. The findings demonstrate that wearable sensor-based gait analysis may be able to help predict clinical measures in individuals after unilateral knee treatment.

Physical Therapist Management of Total Knee Arthroplasty.

A clinical practice guideline on total knee arthroplasty was developed by an American Physical Therapy (APTA) volunteer guideline development group that consisted of physical therapists, an orthopedic surgeon, a nurse, and a consumer. The guideline was based on systematic reviews of current scientific and clinical information and accepted approaches to management of total knee arthroplasty.

Movement pattern biofeedback training after total knee arthroplasty: Randomized clinical trial protocol.

INTRODUCTION: Total knee arthroplasty (TKA) reduces joint symptoms, but habitual movement compensations persist years after surgery. Preliminary research on movement training interventions have signaled initial efficacy for remediating movement compensations and restoring knee joint loading symmetry during dynamic functional tasks after TKA. The purpose of this clinical trial is to determine if physical rehabilitation that includes movement training restores healthy movement patterns after TKA and reduces the risk of osteoarthritis (OA) progression in the contralateral knee. METHODS/DESIGN: 150 participants will be enrolled into this randomized controlled trial. Participants will be randomly allocated to one of two dose-equivalent treatment groups: standard rehabilitation plus movement training (MOVE) or standard rehabilitation without movement training (CONTROL). Movement training will promote between-limb symmetry and surgical knee loading during activity-based exercises. Movement training strategies will include real-time biofeedback using in-shoe pressure sensors and verbal, visual, and tactile cues from the physical therapist. The primary outcome will be change in peak knee extension moment in the surgical knee during walking, from before surgery to six months after surgery. Secondary outcomes will include lower extremity movement symmetry during functional tasks, physical function, quadriceps strength, range of motion, satisfaction, adherence, contralateral knee OA progression, and incidence of contralateral TKA. DISCUSSION: This study will provide insights into the efficacy of movement training after unilateral TKA, along with mechanisms for optimizing long-term physical function and minimizing negative sequelae of compensatory movement patterns.

The effect of extension assist orthosis with pneumatic bladders on pain and function for patients with early knee osteoarthritis.

BACKGROUND: There are few non-invasive treatment options to slow the progression of osteoarthritis (OA). Recently, a novel knee unloader brace with knee extension assist has become commercially available. Therefore, the purpose of this study was to evaluate the preliminary effectiveness of using a novel unloader brace with extension assist to improve pain and functional outcomes for patients with knee OA. METHODS: Thirty subjects (17 control group, 13 brace group) completed baseline and 6-week follow up testing with no brace. Patients were randomized into a Brace or No Brace group after baseline testing. Functional tests [timed up and go (TUG), stair climbing test (SCT) and six-minute walk (6MW)], self-reported measures [Knee Outcome Survey (KOS), pain, Patient Specific Functional Scale (PSFS)] and isometric knee extension strength were assessed. Repeated measure ANOVAs were used to identify differences in group and time. Pearson correlation coefficients were calculated for both average number of steps in the brace and exercises compliance compared to change in clinical scores for each group. RESULTS: There was a significant interaction effect for "worst pain" (P=0.002), the brace group improved from a 7.3/10 to 4.7/10 at follow-up (P=0.006) while the control group had no change. There was an effect of time for the SCT (P=0.02), "best knee pain" (P=0.050), and knee extension range of motion (ROM) (P=0.041). There were no significant correlations between exercise compliance and change in outcomes, but when the groups were collapsed there was a significant correlation between compliance and change in knee extension ROM (r=0.526; P=0.025). CONCLUSIONS: The extension assist pneumatic unloader brace group demonstrated a significant and important reduction in the "worst knee pain". This may indicate that wearing the brace was able to reduce painful flares. Both groups improved over time for the SCT, "best knee pain", and knee extension ROM, which can be attributed to the stretching protocol. This unloader brace is a promising non-invasive treatment option for patients with knee OA when combined with a stretching program.

PROGRESSIVE REHABILITATION AFTER TOTAL HIP ARTHROPLASTY: A PILOT AND FEASIBILITY STUDY.

BACKGROUND: The incidence of total hip arthroplasty (THA) has increased, due in part to younger individuals undergoing the procedure. Surgical techniques and biomaterials have improved, but rehabilitation has not kept pace with the needs of a changing demographic. HYPOTHESIS/PURPOSE: The purpose of this study was to evaluate the feasibility and preliminary effectiveness of a progressive strengthening and functional retraining intervention after THA. STUDY DESIGN: Intervention study. METHODS: Twenty patients participated in the control group (n=10) or experimental group (n=10). The experimental intervention had few supervised sessions in the early phase after THA (weeks 0-12), followed by supervised, progressive, and high-level activity retraining in the later phase (weeks 12-16). Training in the experimental group was tailored to individual patient goals, which included a variety of vocational and recreational activities. The control group participated in usual rehabilitation care as prescribed by their surgeon. Therefore, the duration and content of rehabilitation of the control group therapy was not constrained. Testing included three-dimensional motion analysis of gait and a clinical evaluation prior to surgery and 16 weeks post-surgery. Change scores were calculated for pain, the Timed Up and Go (TUG), the Stair Climb Test (SCT), the Six-minute Walk Test (6MWT), the Thirty Second Chair Rise Test (30-CRT), strength, the Hip Outcome Scale (HOS), the Hip Dysfunction and Osteoarthritis Outcome Score for Joint Replacement (HOOS Jr), ground reaction force during stance, hip abduction moment, sit to stand ground reaction force, and symmetry between limbs during stance and sit to stand and compared between groups. Patient satisfaction and number of rehabilitation visits were also compared. Safety and feasibility were assessed using descriptive analysis of the number adverse events. RESULTS: One patient dropped from the control group prior to rehabilitation. The intervention group had a significantly greater improvement for the 6MWT than the control group (p=0.011), functional questionnaires (p=0.034), hip abduction strength on the non-surgical side (p=0.01) and greater satisfaction (96 vs 84 out of 100; p=0.03) at the conclusion of the intervention. The intervention group demonstrated a significantly greater improvement in force symmetry during sit-to-stand (p=0.041) as compared to the control group. There were no other significant differences in change scores for functional measures or discrete biomechanical metrics. CONCLUSION: This physical therapy protocol, which focused on reducing supervised visits early after THA and retraining higher level activities later in the course of recovery, had a positive effect on biomechanics and functional outcomes without compromising safety. The effect of the experimental intervention was most appreciable for the 6MWT, non-surgical hip strength, satisfaction, and movement symmetry. LEVEL OF EVIDENCE: 2B.

The contralateral knee may not be a valid control for biomechanical outcomes after unilateral total knee arthroplasty.

BACKGROUND: Although unilateral symptoms and unilateral total knee arthroplasty (TKA) are common, many patients have bilateral radiographic osteoarthritis (OA). Because the contralateral (non-operated) limb is often used as a comparison for clinical and biomechanical outcomes, it is important to know if the presence of OA influences movement patterns in either limb. RESEARCH QUESTION: The purpose of this study was to compare bilateral sagittal plane biomechanics between subjects with and without contralateral knee OA after unilateral TKA. METHODS: Fifty-three subjects who underwent unilateral TKA underwent three-dimensional gait analysis 6-24 months after surgery participated in this cross-sectional study. Kellgren-Lawrence (KL) OA severity in the contralateral limb was measured, and subjects were classified into either a non-OA (KL 0 or 1) or OA (KL 2-4) group. Mixed-model ANOVA tests with factors of group and limb were used to compare biomechanical measures. In the presence of a significant interaction effect, post-hoc comparisons were performed. RESULTS: The OA group had more knee flexion at initial contact, less knee flexion and extension excursions, and less knee extension in the contralateral limb compared to the non-OA group. The non-OA group had significant differences between limbs, with more knee flexion at initial contact, less knee joint excursion, and less peak knee extension on the operated limb compared to the contralateral limb, whereas there were no limb differences for the OA group. Kinetic variables were not different in the ANOVA models. SIGNIFICANCE AND INTERPRETATION: Subjects with contralateral knee OA have more symmetrical gait, although they adopt a more abnormal and stiff-legged gait pattern bilaterally. Researchers and clinicians should consider radiographic disease severity, not just symptoms, in the contralateral limb when identifying appropriate subject samples for unilateral biomechanical studies. Symmetrical movement patterns between limbs after surgery should not be the sole factor upon which movement recovery is based.

Stiff knee gait may increase risk of second total knee arthroplasty.

Osteoarthritis (OA) progression in the contralateral limb after unilateral total knee arthroplasty (TKA) may be related to altered and asymmetrical movement patterns that overload the contralateral joints. The purpose of this study was to determine if biomechanical factors after unilateral TKA were associated with future contralateral TKA. One hundred and fifty-eight individuals who underwent unilateral TKA completed three dimensional motion analysis 6-24 months after unilateral TKA (baseline). Subjects were re-contacted for follow-up (mean 5.89 years after baseline testing) to determine if they had undergone a contralateral TKA. Biomechanical variables from gait at baseline were compared between those who did and did not undergo contralateral TKA at follow-up using one-way ANOVAs. Odds ratios were calculated for variables found to be significant in the ANOVA models. Individuals who underwent contralateral TKA had less knee flexion excursion (10.5° vs. 12.1°; p = 0.032) and less knee extension excursion (8.2° vs. 9.6°; p = 0.035) at baseline on the operated side during walking. Individuals who underwent contralateral TKA also had less knee flexion excursion on the contralateral limb at baseline (11.9° vs. 14.0°; p = 0.017). For every additional degree of knee flexion excursion on the contralateral knee at baseline, there was a 9.1% reduction in risk of future contralateral TKA. Individuals who walked with stiffer gait patterns were more likely to undergo future contralateral TKA. Clinical Significance: Altered movement patterns after surgery may increase the risk for contralateral TKA. Knee excursion is an important metric to include in outcome studies and may serve as a target of rehabilitation after TKA. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:397-402, 2019.

ALTERING CADENCE OR VERTICAL OSCILLATION DURING RUNNING: EFFECTS ON RUNNING RELATED INJURY FACTORS.

BACKGROUND: Wearable devices validly assess spatiotemporal running parameters (cadence, vertical oscillation and ground contact time), but the relationship between these parameters and lower limb loading parameters (loading rate, peak vertical ground reaction force [vGRF] and braking impulse) is unknown. PURPOSE: To characterize changes in lower limb loading parameters in runners instructed to run with increased cadence or low vertical oscillation, and to determine whether the change in spatiotemporal parameters predicted the changes in lower limb loading parameters. STUDY DESIGN: Cross Sectional Cohort Study. METHODS: Twenty healthy runners completed three running trials in three conditions: baseline, high cadence, and low vertical oscillation. Spatiotemporal parameters were measured with a wearable device and lower limb loading was measured using an instrumented treadmill. Spatiotemporal and loading parameters were analyzed between running conditions via a repeated measure ANOVA. A hierarchical regression model was used to determine if changes in spatiotemporal parameters predicted the change of loading parameters during conditions. RESULTS: High cadence and low oscillation conditions reduced average vertical loading rate (p = 0.013 and p = 0.002, respectively), instantaneous vertical loading rate (p = 0.022 and p = 0.001, respectively), and peak vGRF (p = 0.025 and p < 0.001, respectively). Braking impulse was significantly lower in the high cadence condition compared to baseline (p < 0.001), but not during the low oscillation (p = 1.000). The increase in cadence during the high cadence condition predicted the reduction of instantaneous vertical loading rate (r2 = 0.213, p = 0.041) and braking impulse (r2 = 0.279, p = 0.017). The reduction in vertical oscillation was more predictive of the change of peak vGRF in both running conditions (high cadence, r2 = 0.436, p = 0.009; low oscillation r2 = 0.748, p < 0.001). CONCLUSION: While both higher cadence and lower vertical oscillation resulted in reduced loading rates during running, cueing to reduce vertical oscillation was more successful in reducing peak vGRF and only the higher cadence condition reduced braking impulse. These findings will inform clinicians who wish to use wearable devices for running gait modification to select injury-specific gait retraining cues. LEVEL OF EVIDENCE: Level 3.

Biomechanical Gait Variable Estimation Using Wearable Sensors after Unilateral Total Knee Arthroplasty.

Total knee arthroplasty is a common surgical treatment for end-stage osteoarthritis of the knee. The majority of existing studies that have explored the relationship between recovery and gait biomechanics have been conducted in laboratory settings. However, seamless gait parameter monitoring in real-world conditions may provide a better understanding of recovery post-surgery. The purpose of this study was to estimate kinematic and kinetic gait variables using two ankle-worn wearable sensors in individuals after unilateral total knee arthroplasty. Eighteen subjects at least six months post-unilateral total knee arthroplasty participated in this study. Four biomechanical gait variables were measured using an instrumented split-belt treadmill and motion capture systems. Concurrently, eleven inertial gait variables were extracted from two ankle-worn accelerometers. Subsets of the inertial gait variables for each biomechanical gait variable estimation were statistically selected. Then, hierarchical regressions were created to determine the directional contributions of the inertial gait variables for biomechanical gait variable estimations. Selected inertial gait variables significantly predicted trial-averaged biomechanical gait variables. Moreover, strong directionally-aligned relationships were observed. Wearable-based gait monitoring of multiple and sequential kinetic gait variables in daily life could provide a more accurate understanding of the relationships between movement patterns and recovery from total knee arthroplasty.

Physical Function After Total Knee Replacement: An Observational Study Describing Outcomes in a Small Group of Women From China and the United States.

OBJECTIVE: To describe physical function before and six months after Total Knee Replacement (TKR) in a small sample of women from China and the United States. DESIGN: Observational. SETTING: Community environment. OUTCOMES: Both groups adhered to the Osteoarthritis Research Society International (OARSI) protocols for the 6-minute walk and 30-second chair stand. We compared physical function prior to TKR and 6 months after using linear regression adjusted for covariates. PARTICIPANTS: Women (N=60) after TKR. INTERVENTIONS: Not applicable. RESULTS: Age and body mass index in the China group (n=30; 66y and 27.0kg/m2) were similar to those in the U.S. group (n=30; 65y and 29.6kg/m2). Before surgery, the China group walked 263 (95% confidence interval [CI], -309 to -219) less meters and had 10.2 (95% CI, -11.8 to -8.5) fewer chair stands than the U.S. group. At 6 months when compared with the U.S. group, the China group walked 38 more meters, but this difference did not reach statistical significance (95% CI, -1.6 to 77.4), and had 3.1 (95% CI, -4.4 to -1.7) fewer chair stands. The China group had greater improvement in the 6-minute walk test than did the U.S. group (P<.001). CONCLUSIONS: Despite having worse physical function before TKR, the China group had greater gains in walking endurance and similar gains in repeated chair stands than did the U.S. group after surgery.

The effect of surgical approach on gait mechanics after total hip arthroplasty.

BACKGROUND: Few studies have compared the biomechanical outcomes of different surgical approaches for hip arthroplasty. The purpose of this study was to compare hip, pelvic, and trunk kinematics and kinetics between individuals who underwent a posterior or anterolateral approach. METHODS: Forty-five individuals between 40 and 80 years old underwent motion analysis during overground gait prior to hip arthroplasty and 3 months after surgery. Walking speed, hip flexion angle, hip extension angle, adduction angle and moment, trunk angle, trunk lean, and pelvis drop were compared between approaches. FINDINGS: There were 30 subjects in the posterior group and 15 subjects in the anterolateral group. The groups did not change differently over time as there were no significant interaction effects. However, there were main effects for time; walking speed increased 19.9% (p < .001), hip flexion angle increased 3.3 degrees (p = 0.014) and peak hip extension increased 4.5 degrees (p = .001), and peak hip adduction significantly increased 1.9 degrees (p = .004) for the sample as a whole. Trunk angle (p = .283) and trunk lean (p = .401) did not significantly change between time points, but there was a significant increase in pelvic drop (p = .003). INTERPRETATION: Surgical approach did not affect biomechanical outcomes 3 months after arthroplasty. Both groups showed improvement in sagittal plane hip kinetics and kinematics. However, increased pelvic drop may be indicative of residual hip weakness in both groups.

Influence of weight bearing visual feedback on movement symmetry during sit to stand task.

BACKGROUND: Weight-bearing asymmetry is common in individuals with hip osteoarthritis and after total hip arthroplasty. Including symmetry training to the rehabilitation programs may normalize movement strategies during dynamic tasks. The purpose of this study was to evaluate the immediate influences of real-time visual feedback of weight distribution on the interlimb movement symmetry during the sit-to-stand task, before and after total hip arthroplasty, and to determine whether physical impairments affect the response to visual feedback. METHODS: Subjects before and after total hip arthroplasty participated in three- dimensional motion analysis. Subjects completed 3 trials of sit-to-stand task in two conditions; "without visual feedback" and "with visual feedback". Outcome measures were the interlimb symmetry of vertical ground reaction force, and joint kinematics and kinetics. Pain and strength of lower limbs were assessed. FINDINGS: Compared to "without visual feedback" condition, subjects moved with greater symmetry of vertical ground reaction force and joint kinetics when visual feedback was received. However, subjects continued to demonstrate interlimb difference for joint kinetics and vertical ground reaction force in the visual feedback condition. The increase in symmetry was not strongly influenced by physical impairments and subjects before and after total hip arthroplasty responded similarly to the feedback. INTERPRETATIONS: We concluded that in a single session, the visual feedback of weight bearing distribution had a positive immediate effect on movement symmetry during the sit-to-stand task. Future studies that assess long-term retention and functional benefits are warranted before visual feedback is incorporated in rehabilitation for this patient population.