Long-term effectiveness of Sorbie-QUESTOR elbow arthroplasty: single surgeon's series of 15 years.

With increasing usage of many types of total elbow replacements, there is a continuing need for clinical series that report survivorship, complications and revisions, and performance of single types of implants over extended time periods. The purpose of this study was to assess the long-term effectiveness of all implants of the Sorbie-QUESTOR (SQ) unlinked surface arthroplasty conducted by a single surgeon (C.S.) over 15 years at a single site, and to determine whether there were diagnostic group differences. Between 1995 and 2002, 51 S-Q prosthetic elbows were implanted into 44 patients. The patient groups were hemophilia, rheumatoid arthritis, and "other," which included osteoarthritis, traumatic arthritis, psoriatic arthritis, and reactive arthritis. Annual evaluations included scores of pain, range of motion, and function. The most recent annual evaluation was included in the data set. Details of complications and revisions were recorded. The hemophiliac group had the best survival outcomes at 87.5%. Eighteen prostheses required revision or removal with all but 3 retained or replaced. Postoperatively, 73% rated their pain as 'slight' or 'none'. The hemophilia and rheumatoid arthritis groups made very large total flexion/extension gains. The rheumatoid arthritis group made significant forearm motion gains. Average functional assessment gains were nearly 2 grades of 5 functional levels and were significant for all groups. The S-Q surface arthroplasty has demonstrated long-term effectiveness in patients with a variety of elbow joint pathologies showing reduction in pain, large gains in joint range and function, and good long-term survival.

Effect of a home program of hip abductor exercises on knee joint loading, strength, function, and pain in people with knee osteoarthritis: a clinical trial.

BACKGROUND: Hip abductor muscle weakness may result in impaired frontal-plane pelvic control during gait, leading to greater medial compartment loading in people with knee osteoarthritis (OA). OBJECTIVE: This study investigated the effect of an 8-week home strengthening program for the hip abductor muscles on knee joint loading (measured by the external knee adduction moment during gait), strength (force-generating capacity), and function and pain in individuals with medial knee OA. DESIGN: The study design was a nonequivalent, pretest-posttest, control group design. SETTING: Testing was conducted in a motor performance laboratory. PATIENTS: An a priori sample size calculation was performed. Forty participants with knee OA were matched for age and sex with a control group of participants without knee OA. INTERVENTION: Participants with knee OA completed a home hip abductor strengthening program. MEASUREMENTS: Three-dimensional gait analysis was performed to obtain peak knee adduction moments in the first 50% of the stance phase. Isokinetic concentric strength of the hip abductor muscles was measured using an isokinetic dynamometer. The Five-Times-Sit-to-Stand Test was used to evaluate functional performance. Knee pain was assessed with the Western Ontario and McMaster Universities Osteoarthritis Index questionnaire. RESULTS: Following the intervention, the OA group demonstrated significant improvement in hip abductor strength, but not in the knee adduction moment. Functional performance on the sit-to-stand test improved in the OA group compared with the control group. The OA group reported decreased knee pain after the intervention. LIMITATIONS: Gait strategies that may have affected the knee adduction moment, including lateral trunk lean, were not evaluated in this study. CONCLUSIONS: Hip abductor strengthening did not reduce knee joint loading but did improve function and reduce pain in a group with medial knee OA.

Gait changes following botulinum toxin A treatment in stroke.

PURPOSE: To characterize the effects of botulinum toxin A treatment of spastic plantar flexors in stroke on joint mobility and gait kinematics and kinetics. METHOD: Nine patients with hemiparetic stroke presenting with ankle hypertonicity participated in this exploratory open-label case series study. Comprehensive gait analysis provided bilateral kinematic and kinetic information for the ankle, knee, and hip joints throughout the stance phase. Data were obtained at baseline, 2 weeks, and 10 weeks post botulinum toxin injection of the spastic plantar flexors. RESULTS: Passive ankle range of motion increased post injection (p < .05). The amount of plantarflexion in late stance was significantly reduced (p < .05) while the maximum dorsiflexion increased in midstance at 10 weeks post treatment. The angular displacement profiles for the knee revealed that patients tended to display less hyperextension following treatment (p = .053). No significant changes in kinetic measures were found; however, case-by-case observations suggested that most patients experienced improvements in positive work production. CONCLUSIONS: The findings indicate that botulinum toxin treatment results in improved joint mobility and ankle kinematics and, in some patients, increases in positive work, suggesting better gait performance.

A comparison of gait biomechanics and metabolic requirements of overground and treadmill walking in people with stroke.

BACKGROUND: Comparisons of treadmill and overground walking following stroke indicate that symmetry in temporal-distance measures is better on the treadmill suggestive of better gait economy. We examined this issue by examining the kinematic, kinetic and metabolic demands associated with overground and treadmill walking at matched speeds and also explored the effect of increasing treadmill speed. METHODS: Ten people with hemiparesis walked overground at their preferred speed which was matched on the treadmill. Belt speed was then increased 10% and 20% above preferred speed. Temporal-distance outcomes, angular kinematics and vertical ground reaction forces were recorded during steady state (stable heart rate and oxygen uptake). FINDINGS: Step and stance times were longer when walking overground but the degree of symmetry was comparable for both surfaces. In contrast kinematic data revealed significant interlimb asymmetry with respect to all lower limb joint excursions during overground walking accompanied by higher vertical ground reaction forces at push-off. The metabolic demands, however, were lower when walking overground than on the treadmill. Increasing the belt speed increased angular displacements and the vertical forces associated with both limbs such that symmetry remained unchanged. Metabolic demands increased significantly. INTERPRETATION: People with stroke adopt a more symmetrical kinematic walking pattern on the treadmill which is maintained at faster belt speeds. Surprisingly, at matched speed the metabolic cost was significantly higher with treadmill walking. We suggest further research to explore whether an increased reliance on the hip musculature to compensate lower push-off forces could explain the higher the energy cost.

Kinematic, kinetic and metabolic parameters of treadmill versus overground walking in healthy older adults.

BACKGROUND: Although treadmill and overground walking appear to be biomechanically similar in healthy, young adults it is not known whether this can be generalized to older subjects or if the metabolic demands are correspondingly comparable. METHODS: Ten healthy adults between 50 and 73 years of age walked at the same speed overground and on a treadmill. Temporal parameters, angular kinematics and vertical ground reaction forces were recorded during walking once subjects were in steady state as determined from their heart rate and oxygen uptake. FINDINGS: Step, stride and joint angular kinematics were similar for both modes of walking with the exception of the maximum hip flexion and knee extension which were more pronounced with treadmill or overground walking, respectively but in both instances differed by less than 3 degrees. Vertical ground reaction force profiles were similar although the peak associated with push-off was 5.5% smaller with treadmill walking. The metabolic requirements of treadmill walking were about 23% higher than that associated with overground walking. INTERPRETATION: While treadmill and overground walking are biomechanically similar, the metabolic cost of treadmill walking is higher. Clinically this may be important when using a treadmill for gait retraining in patient populations as it may lead to premature fatigue or undesirable physiologic challenge.

Mechanical factors relate to pain in knee osteoarthritis.

BACKGROUND: Pain experienced by people with knee osteoarthritis is related to psychosocial factors and damage to articular tissues and/or the pain pathway itself. Mechanical factors have been speculated to trigger this pain experience; yet mechanics have not been identified as a source of pain in this population. The purpose of this study was to identify whether mechanics could explain variance in pain intensity in people with knee osteoarthritis. METHODS: Data from 53 participants with physician-diagnosed knee osteoarthritis (mean age=68.5 years; standard deviation=8.6 years) were analyzed. Pain intensity was reported on the Western Ontario and McMaster Universities Osteoarthritis Index. Mechanical measures included weight-bearing varus-valgus alignment, body mass index and isokinetic quadriceps torque. Gait analysis captured the range of adduction-abduction angle, range of flexion-extension angle and external knee adduction moment during level walking. FINDINGS: Pain intensity was significantly related to the dynamic range of flexion-extension during gait and body mass index. A total of 29% of the variance in pain intensity was explained by mechanical variables. The range of flexion-extension explained 18% of variance in pain intensity. Body mass index added 11% to the model. The knee adduction moment was unrelated to pain intensity. INTERPRETATION: The findings support that mechanical factors are related to knee osteoarthritis pain. Because limitations in flexion-extension range of motion and body size are modifiable factors, future research could examine whether interventions targeting these mechanics would facilitate pain management.

Self-efficacy mediates walking performance in older adults with knee osteoarthritis.

BACKGROUND: Self-efficacy is a determinant of walking performance in older adults with knee osteoarthritis. We examined whether self-efficacy mediated the effect of age, psychosocial, impairment, and mechanical factors on walking performance. METHODS: Fifty-four participants with knee osteoarthritis completed the Six Minute Walk test and Arthritis Self-Efficacy Scale. Independent variables reflected age, psychosocial (depressive symptoms), impairment (pain, stiffness), and mechanical (strength, obesity) factors. RESULTS: Self-efficacy fully mediated the effect of age and impairments on walking. The effects of strength were only partially mediated by self-efficacy. Depressive symptoms and obesity were not mediated by self-efficacy. CONCLUSIONS: These findings are consistent with Social Cognitive Theory, according to which age may alter outcome expectations, and impairments like pain and stiffness provide negative physiological feedback to influence performance. Mechanical factors like strength and obesity may better represent a person's capabilities and interact with other variables to influence physical performance in older adults with knee osteoarthritis.

Changes in muscle group work associated with changes in gait speed of persons with stroke.

BACKGROUND: Knowledge of associations between changes in muscle work with changes in gait speed could assist gait training in persons with stroke. The purpose of the study was to determine changes in the work of major muscle groups during gait that were associated with increases in walking speed of persons with stroke following training. METHODS: The gait of 28 subjects (14 males, 14 females) with mean age of 64.2 (SD 11.7) years, at 4.8 (SD 6.9) years post stroke was studied using two-dimensional motion analysis before and after a strength training program. Outcome variables were changes in gait speed and changes in work associated with the hip flexors and extensors, knee flexors and extensors and ankle plantar flexors bilaterally. A stepwise linear regression analysis determined best positive work predictors of changes in gait speed. FINDINGS: Hip extension work in early stance and ankle plantarflexion work in late stance of the affected side accounted for 74.9% of the variance in change of gait speed; a second model showed that hip extension work in early stance of the affected and less-affected sides accounted for 74.3%, a similar amount of variance. INTERPRETATION: This work is the first to explore the changes in muscle work during gait that are associated with speed increases in persons with stroke. Augmenting hip extensor work in early stance on both sides, as well as ankle plantarflexion thrust on the affected side may be particularly beneficial in increasing the speed of walking of persons with stroke.

Role of knee kinematics and kinetics on performance and disability in people with medial compartment knee osteoarthritis.

BACKGROUND: Although gait characteristics have been well documented in people with knee osteoarthritis, little is known about the relationships between gait characteristics and performance or disability. Our purpose was to examine the role of knee kinematics and kinetics on walking performance and disability in people with knee osteoarthritis. We also examined whether pain mediated the relationship between the knee adduction moment and performance or disability. METHODS: Three-dimensional gait analysis was conducted on 54 people with medial compartment knee osteoarthritis. Performance was quantified with the Six Minute Walk test and disability was self-reported on the Short Form-36. The pain subscale of the Western Ontario McMaster Universities Osteoarthritis Index and the functional self-efficacy subscale of the Arthritis Self-Efficacy scale were completed. FINDINGS: A step-wise linear regression demonstrated that the variance in Six Minute Walk test scores was explained by functional self-efficacy (50%) and the range of knee motion (8%). The variance in Short Form-36 was explained by pain (36%), the peak extension angle (19%) and the range of knee motion (4%). Pain was unrelated to the knee adduction moment so analyses of pain as a mediator of the adduction moment on either performance or disability were halted. INTERPRETATION: Kinematic output from the motor control system is useful in understanding some variance in current performance and disability in people with knee osteoarthritis. The knee adduction moment was unrelated to these variables and pain did not mediate between the knee adduction moment and performance or disability. Therefore this moment does not explain current clinical status in people with knee osteoarthritis based on the measures of performance and disability used in this study.

Accuracy of clinical observations of push-off during gait after stroke.

OBJECTIVE: To determine the accuracy (criterion-related validity) of real-time clinical observations of push-off in gait after stroke. DESIGN: Criterion-related validity study of gait observations. SETTING: Rehabilitation hospital in Australia. PARTICIPANTS: Eleven participants with stroke and 8 treating physical therapists. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Pearson product-moment correlation between physical therapists' observations of push-off during gait and criterion measures of peak ankle power generation from a 3-dimensional motion analysis system. RESULTS: A high correlation was obtained between the observational ratings and the measurements of peak ankle power generation (Pearson r =.98). The standard error of estimation of ankle power generation was .32W/kg. CONCLUSIONS: Physical therapists can make accurate real-time clinical observations of push-off during gait following stroke.

Determinants of self efficacy for physical tasks in people with knee osteoarthritis.

OBJECTIVE: Self efficacy, the confidence an individual has to perform a task, is an important determinant of physical performance in individuals with knee osteoarthritis (OA). The purpose of this study was to determine what personal, pathophysiologic, and impairment factors relate to self efficacy for physical tasks in community-dwelling adults with knee OA. METHODS: Fifty-four persons with radiographically confirmed knee OA (mean +/- SD age 68.3 +/- 8.7 years, range 50-87 years) participated. The Functional Self-Efficacy subscale of the Arthritis Self-Efficacy Scale was the dependent measure. Independent measures included age, education, scores from the Center for Epidemiologic Studies Depression and State-Trait Anxiety Inventory questionnaires, medial joint space and varus/valgus tibiofemoral angle from radiographs, body mass index, and isokinetic quadriceps and hamstrings strength. Knee pain and stiffness, assessed using the Western Ontario and McMaster Universities Osteoarthritis Index, were independent measures. RESULTS: Fifty-one percent of the variance of Functional Self Efficacy was explained by knee stiffness, hamstrings strength, age, and depression scores. Pain, education, anxiety, radiographic joint space, and body weight did not significantly contribute to the variance in Functional Self-Efficacy scores. Substituting quadriceps strength for hamstrings strength resulted in a regression model that included only stiffness, age, and depression, which explained nearly as much variance as the original model. CONCLUSION: Self efficacy for physical tasks is related to the sensation of stiffness, hamstrings strength, age, and level of depressive symptoms in persons with knee OA. Clinicians and researchers could consider these variables when assessing the level of self efficacy for physical tasks in persons with knee OA.

A randomized controlled trial of supervised versus unsupervised exercise programs for ambulatory stroke survivors.

BACKGROUND AND PURPOSE: Little is known about the relative efficacy of supervised versus unsupervised community exercise programs for stroke survivors. This study compared the effectiveness of a 10-week supervised strengthening and conditioning program (supervised) with a 1-week supervised instruction program followed by a 9-week unsupervised home program (unsupervised) and evaluated retention of changes at 6 months and 1 year after program completion. METHODS: Seventy-two subjects retained at baseline (27 women, 45 men; mean+/-SD age, 64.6+/-11.8 years) were randomly allocated to receive the supervised or unsupervised program. The primary outcome was walking speed over 6 minutes, and secondary outcome measures were Human Activity Profile, Medical Outcome Study 36-Item Short-Form survey (SF-36), Physiological Cost Index, and lower extremity muscle strength. RESULTS: The 6-minute walking speed increased significantly in both groups and remained significantly improved by 1 year. The Human Activity Profile demonstrated an increasing trend only in the supervised group that was significant by 1 year. The SF-36 Physical Component summary score increased significantly in the supervised group and remained improved by 1 year; the unsupervised group showed significant improvement at 1 year. Women made greater gains in supervised programs, but men made greater gains in unsupervised programs. CONCLUSIONS: Supervised exercise programs and unsupervised programs after initial supervised instruction were both associated with physical benefits that were retained for 1 year, although supervised programs showed trends to greater improvements in self-reported gains. Gender differences require further research.

Determinants of self-report outcome measures in people with knee osteoarthritis.

OBJECTIVES: To identify the determinants of self-report mobility measures in people with knee osteoarthritis (OA) and to compare self-report measures with physical performance. DESIGN: Cross-sectional, prospective. SETTING: Motor performance laboratory and human mobility research center. PARTICIPANTS: A convenient sample of 54 participants with medial compartment knee OA (32 women, 22 men; age 68.3+/-8.7y; range, 50-87y). Three participants were excluded because of the presence of lateral knee OA on radiographs. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Self-reports were recorded by using the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) and the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36). Performance measures included the six-minute walk test (6MWT), Timed Up & Go (TUG) test, and a standardized stair-climbing task (STR). RESULTS: Stepwise linear regression analysis identified models that included pain, quadriceps and hamstrings strength, and depression to explain 62% to 73% of the variance in scores on the physical functioning subscale of the WOMAC and the SF-36. These self-report measures had a moderate relation (r range, .46-.64) with performance measures (6MWT, TUG, STR). CONCLUSIONS: Self-report measures were strongly related to pain; physical performance measures were strongly related to self-efficacy. Regression models showed that self-report scores reflect pain, knee strength, and depression. The relation between self-report and performance measures was moderate, suggesting that these examine different aspects of mobility.

Contribution of psychosocial and mechanical variables to physical performance measures in knee osteoarthritis.

BACKGROUND AND PURPOSE: This cross-sectional study evaluated the relative contributions of psychosocial and mechanical variables to physical performance measures in people with knee osteoarthritis (OA). SUBJECTS: Fifty-four subjects (age, in years: mean=68.3, SD=8.7, range=50-87) with radiographically confirmed knee OA were included in this study. METHODS: Physical performance measures included the Six-Minute Walk Test (SMW), the Timed "Up & Go" Test (TUG), and a stair-climbing task (STR). Responses to psychosocial questionnaires that reflect depression, anxiety, and self-efficacy (a person's confidence in his or her ability to complete a task) were collected. Mechanical variables measured included body mass index and knee strength (force-generating capacity of muscle). Stepwise linear regressions were performed with the SMW, TUG, and STR as separate dependent variables. RESULTS: Functional self-efficacy explained the greatest amount of variance in all performance measures, contributing 45% or more. Knee strength and body weight also explained some variance in performance measures. Anxiety and depression did not explain any variance in performance. DISCUSSION AND CONCLUSION: Physical therapists evaluating the significance of the SMW, TUG, and STR scores in subjects with knee OA should note that a large part of each score reflects self-efficacy, or confidence, for physical tasks, with some contributions from knee strength and body weight.

Accuracy and reliability of observational gait analysis data: judgments of push-off in gait after stroke.

BACKGROUND AND PURPOSE: Physical therapists routinely observe gait in clinical practice. The purpose of this study was to determine the accuracy and reliability of observational assessments of push-off in gait after stroke. SUBJECTS: Eighteen physical therapists and 11 subjects with hemiplegia following a stroke participated in the study. METHODS: Measurements of ankle power generation were obtained from subjects following stroke using a gait analysis system. Concurrent videotaped gait performances were observed by the physical therapists on 2 occasions. Ankle power generation at push-off was scored as either normal or abnormal using two 11-point rating scales. These observational ratings were correlated with the measurements of peak ankle power generation. RESULTS: A high correlation was obtained between the observational ratings and the measurements of ankle power generation (mean Pearson r=.84). Interobserver reliability was moderately high (mean intraclass correlation coefficient [ICC (2,1)]=.76). Intraobserver reliability also was high, with a mean ICC (2,1) of.89 obtained. DISCUSSION AND CONCLUSION: Physical therapists were able to make accurate and reliable judgments of push-off in videotaped gait of subjects following stroke using observational assessment. Further research is indicated to explore the accuracy and reliability of data obtained with observational gait analysis as it occurs in clinical practice.