Implications of Walking Aid Selection for Nonweightbearing Ambulation on Stance Limb Plantar Force, Walking Speed, Perceived Exertion, and Device Preference in Healthy Adults 50 Years of Age and Older.

BACKGROUND: Young adults often tolerate the increased energy expenditure, coordination, and stance limb discomfort associated with walking aids for nonweightbearing ambulation. Adults aged ≥50 years may not have the same tolerance. Therefore, the objective of this study was to determine how walking aid selection affects stance limb plantar force, walking speed, perceived exertion, and device preference in adults aged ≥50 years. METHODS: A prospective randomized crossover study was performed using healthy adults, aged ≥50 years, with no use of walking aids within 5 years. Participants walked 200 m in 4 randomized conditions: single nonweightbearing ambulation using crutches, a walker, a wheeled knee walker, and unaided walking. An in-shoe sensor measured stance limb plantar force, a stopwatch timed each walk, perceived exertion was reported using the BORG CR-10 scale, and device preference was identified. RESULTS: Twenty-one participants (7 male; age: 56 ± 5 years; BMI: 26.6 ±1.9) showed stance limb plantar force was lowest when using a wheeled knee walker (P < .001). Walking speed was similar in unaided and wheeled knee walker conditions (1.41 and 1.31 m/s), but slower with crutches or a walker (42%-68%, P < .001). Perceived exertion was similar in unaided and wheeled knee walker conditions (1.6 and 2.8), but higher with crutches or a walker (5.7 and 6.1, P < .001). Most (20/21) participants preferred the wheeled knee walker. CONCLUSIONS: Using a wheeled knee walker for nonweightbearing ambulation reduced stance limb plantar force, maintained unaided walking speed and perceived exertion, and was preferred to crutches or a walker. LEVEL OF EVIDENCE: Level II, comparative study.

Changes to stance limb peak, cumulative, and regional plantar foot forces among normal walking and three mobility aids in healthy older adults.

BACKGROUND: Mobility aids are commonly prescribed to offload an injured lower extremity. Device selection may impact stance foot loading patterns and foot health in clinical populations at risk of foot ulceration. RESEARCH QUESTIONS: Two questions motivated this study: How does device selection influence peak plantar and regional (rearfoot, mid foot and forefoot) foot forces on the stance foot? Does device selection influence peak, cumulative, and regional plantar forces within a 200 m walking trial? METHODS: Twenty-one older adults walked 200 m at self-selected pace in four randomized conditions for this prospective crossover study. Participants used a walker, crutches, wheeled knee walker (WKW), and no assistive device (control condition). Plantar forces were measured using a wireless in-shoe system (Loadsol, Novel Inc., St. Paul, MN). Repeated measures analyses of variance were used to determine differences in peak and cumulative total and regional forces among walking conditions. Paired sample t-tests compared forces during first and last 30 s epochs of each condition to determine device influence over time. RESULTS: The WKW reduced peak net forces by 0.29 and 0.35 bodyweight (BW) when compared to the walker or control condition with similar trends in all foot regions. Crutch use had similar peak forces as control. There were no differences in the number of steps taken within devices comparing first and last epochs. Crutches had a 0.04 and 0.07 BW increase in peak net and forefoot forces during the last epoch. Walker use had 66.44 BW lower cumulative forefoot forces in the last epoch. SIGNIFICANCE: Crutches had similar stance foot loading as normal walking while a walker lowered forefoot forces at the expense of increased steps. A WKW may be the best choice to 'protect' tissues in the stance foot from exposure to peak and cumulative forces in the forefoot region.

Tibiofemoral Rotation During Sit-to-Stand Activity After TKA.

The objective of this study was to describe how tibiofemoral internal/external rotation varies in patients after total knee arthroplasty (TKA) when compared with control participants during a sit-to-stand (STS) maneuver. Motion analysis was used to measure internal/external knee rotation during STS in the control and TKA groups. Fourteen participants were included in the study. Six patients with 7 TKA knees (6 posterior stabilized and 1 cruciate-retaining TKA) were compared with 8 control participants with 8 knees from the current authors' laboratory database. Participants performed 3 STS maneuvers, and the average internal/external rotation of the femur with respect to the tibia was compared. All control participants and 2 TKA participants had internal rotation of the femur with respect to the tibia, whereas 4 TKA participants had external rotation, and 1 had no rotation during STS. Further investigation into the surgical and patient- and implant-related factors that affect this resulting reverse kinematic profile seems to be warranted. [Orthopedics. 2016; 39(3):S41-S44.].

Antidepressant Use and Recurrent Falls in Community-Dwelling Older Adults: Findings From the Health ABC Study.

BACKGROUND: Few studies have compared the risk of recurrent falls across various antidepressant agents-using detailed dosage and duration data-among community-dwelling older adults, including those who have a history of a fall/fracture. OBJECTIVE: To examine the association of antidepressant use with recurrent falls, including among those with a history of falls/fractures, in community-dwelling elders. METHODS: This was a longitudinal analysis of 2948 participants with data collected via interview at year 1 from the Health, Aging and Body Composition study and followed through year 7 (1997-2004). Any antidepressant medication use was self-reported at years 1, 2, 3, 5, and 6 and further categorized as (1) selective serotonin reuptake inhibitors (SSRIs), (2) tricyclic antidepressants, and (3) others. Dosage and duration were examined. The outcome was recurrent falls (≥2) in the ensuing 12-month period following each medication data collection. RESULTS: Using multivariable generalized estimating equations models, we observed a 48% greater likelihood of recurrent falls in antidepressant users compared with nonusers (adjusted odds ratio [AOR] = 1.48; 95% CI = 1.12-1.96). Increased likelihood was also found among those taking SSRIs (AOR = 1.62; 95% CI = 1.15-2.28), with short duration of use (AOR = 1.47; 95% CI = 1.04-2.00), and taking moderate dosages (AOR = 1.59; 95% CI = 1.15-2.18), all compared with no antidepressant use. Stratified analysis revealed an increased likelihood among users with a baseline history of falls/fractures compared with nonusers (AOR = 1.83; 95% CI = 1.28-2.63). CONCLUSION: Antidepressant use overall, SSRI use, short duration of use, and moderate dosage were associated with recurrent falls. Those with a history of falls/fractures also had an increased likelihood of recurrent falls.

Increased hip abduction in high body mass index subjects during sit-to-stand.

Obesity is associated with increased risk of total hip arthroplasty (THA) dislocation. Differences in kinematics and kinetics at the hip during activities of daily living such as sit-to-stand (STS) may contribute to this risk. Nine high body mass index (BMI) subjects (mean BMI 31.2) and ten normal BMI control subjects (mean BMI 22.1) were analyzed using force plates and an optoelectronic motion capture camera system during controlled STS movement. Flexion/extension, abduction/adduction, and internal/external rotation angles and moments at the hip and knee were calculated using a musculoskeletal model. No differences were found at the knee. Peak hip abduction angles were on average 50% greater in the high BMI group compared to the normal group (p=0.038). The hip was roughly 50% more abducted throughout the entire STS cycle in the high BMI group. Peak normalized hip abduction moments were approximately twice as large in the high BMI group (p=0.005). Further research is required to determine if this increase in abduction angle and moment observed during STS is a contributor to risk for complications following THA in obese subjects.

LC-MS/MS identification of the one-carbon cycle metabolites in human plasma.

The one-carbon cycle is composed of four major biologically important molecules: methionine (L-Met), S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), and homocysteine (Hcy). In addition to these key metabolites, there are multiple enzymes, vitamins, and cofactors that play essential roles in the cascade of the biochemical reactions that convert one metabolite into another in the cycle. Simultaneous quantitative measurement of four major metabolites can be used to detect possible aberrations in this vital cycle. Abnormalities in the one-carbon cycle might lead to hyper- or hypomethylation, homocystinemia, liver dysfunction, and accumulation of white-matter hyperintensities in the human brain. Previously published methods describe evaluation of several components of the one-carbon cycle, but none to our knowledge demonstrated simultaneous measurement of all four key molecules (L-Met, SAM, SAH, and Hcy). We describe a novel analytical method suitable for simultaneous identification and quantification of L-Met, SAM, SAH, and Hcy with LC-MS/MS. Moreover, we tested this method to identify these metabolites in human plasma collected from patients with multiple sclerosis and healthy individuals. In a pilot feasibility study, our results indicate that patients with multiple sclerosis showed abnormalities in the one-carbon cycle.

Principal component analysis of knee kinematics and kinetics after anterior cruciate ligament reconstruction.

This study compared the gait of 10 subjects with unilateral anterior cruciate ligament (ACL) reconstruction to a group of 12 height- and weight-matched control subjects. The analysis was based on knee flexion, adduction, and internal rotation angles and moments. The objective was to use principal component analysis (PCA) to identify knees of the ACL reconstructed subjects that fell outside normal ranges as determined by control subjects. Gait data were collected on all subjects in a motion analysis laboratory. Principal component (PC) models were developed for each gait measure based on the control subjects' data and used to assess gait waveforms of ACL reconstructed subjects. PCA allows analysis of entire gait waveforms for comparisons. In a sample of 10 ACL reconstructed subjects (7 years after surgery, on average), six of the ACL reconstructed knees had not returned to normal following surgery and eight of the contralateral knees functioned differently from controls. A majority of the differences were noted to occur in the abduction-adduction knee moment with corresponding infrequency in the differences seen in abduction-adduction rotation. PCA enabled us to identify subjects with abnormal gait waveforms as outliers relative to the normal control group.

Effects of a 6-week, individualized, supervised exercise program for people with bleeding disorders and hemophilic arthritis.

BACKGROUND: People with bleeding disorders may develop severe arthritis due to joint hemorrhages. Exercise is recommended for people with bleeding disorders, but guidelines are vague and few studies document efficacy. In this study, 65% of people with bleeding disorders surveyed reported participating in minimal exercise, and 50% indicated a fear of exercise-induced bleeding, pain, or physical impairment. OBJECTIVE: The purpose of this study was to examine the feasibility, safety, and efficacy of a professionally designed, individualized, supervised exercise program for people with bleeding disorders. DESIGN: A single-group, pretest-posttest clinical design was used. METHODS: Thirty-three patients (3 female, 30 male; 7-57 years of age) with mild to severe bleeding disorders were enrolled in the study. Twelve patients had co-existing illnesses, including HIV/AIDS, hepatitis, diabetes, fibromyalgia, neurofibromatosis, osteopenia, osteogenesis imperfecta, or cancer. Pre- and post-program measures included upper- and lower-extremity strength (force-generating capacity), joint range of motion, joint and extremity circumference, and distance walked in 6 minutes. Each patient was prescribed a 6-week, twice-weekly, individualized, supervised exercise program. Twenty participants (61%) completed the program. RESULTS: Pre- and post-program data were analyzed by paired t tests for all participants who completed the program. No exercise-induced injuries, pain, edema, or bleeding episodes were reported. Significant improvements occurred in joint motion, strength, and distance walked in 6 minutes, with no change in joint circumference. The greatest gains were among the individuals with the most severe joint damage and coexisting illness. LIMITATIONS: Limitations included a small sample size with concomitant disease, which is common to the population, and a nonblinded examiner. CONCLUSIONS: A professionally designed and supervised, individualized exercise program is feasible, safe, and beneficial for people with bleeding disorders, even in the presence of concomitant disease. A longitudinal study with a larger sample size, a blinded examiner, and a control group is needed to confirm the results.