Lee Dibble

Total Knee Arthroplasty: Muscle Impairments, Functional Limitations, and Recommended Rehabilitation Approaches

UNLABELLED The number of total knee arthroplasty (TKA) surgeries performed each year is predicted to steadily increase. Following TKA surgery, self-reported pain and function improve, though individuals are often plagued with quadriceps muscle impairments and functional limitations. Postoperative rehabilitation approaches either are not incorporated or incompletely address the muscular and functional deficits that persist following surgery. While the reason for quadriceps weakness is not well understood in this patient population, it has been suggested that a combination of muscle atrophy and neuromuscular activation deficits contribute to residual strength impairments. Failure to adequately address the chronic muscle impairments has the potential to limit the long-term functional gains that may be possible following TKA. Postoperative rehabilitation addressing quadriceps strength should mitigate these impairments and ultimately result in improved functional outcomes. The purpose of this paper is to describe these quadriceps muscle impairments and discuss how these impairments can contribute to the related functional limitations following TKA. We will also describe the current concepts in TKA rehabilitation and provide recommendations and clinical guidelines based on the current available evidence. LEVEL OF EVIDENCE Therapy, level 5.

Total knee arthroplasty

UNLABELLED The number of total knee arthroplasty (TKA) surgeries performed each year is predicted to steadily increase. Following TKA surgery, self-reported pain and function improve, though individuals are often plagued with quadriceps muscle impairments and functional limitations. Postoperative rehabilitation approaches either are not incorporated or incompletely address the muscular and functional deficits that persist following surgery. While the reason for quadriceps weakness is not well understood in this patient population, it has been suggested that a combination of muscle atrophy and neuromuscular activation deficits contribute to residual strength impairments. Failure to adequately address the chronic muscle impairments has the potential to limit the long-term functional gains that may be possible following TKA. Postoperative rehabilitation addressing quadriceps strength should mitigate these impairments and ultimately result in improved functional outcomes. The purpose of this paper is to describe these quadriceps muscle impairments and discuss how these impairments can contribute to the related functional limitations following TKA. We will also describe the current concepts in TKA rehabilitation and provide recommendations and clinical guidelines based on the current available evidence. LEVEL OF EVIDENCE Therapy, level 5.

Testing balance and fall risk in persons with Parkinson disease, an argument for ecologically valid testing

INTRODUCTION Despite clear deficits in postural control, most clinical examination tools lack accuracy in identifying persons with Parkinson disease (PD) who have fallen or are at risk for falls. We assert that this is in part due to the lack of ecological validity of the testing. METHODS To test this assertion, we examined the responsiveness and predictive validity of the Functional Gait Assessment (FGA), the Pull test, and the Timed up and Go (TUG) during clinically defined ON and OFF medication states. To address responsiveness, ON/OFF medication performance was compared. To address predictive validity, areas under the curve (AUC) of receiver operating characteristic (ROC) curves were compared. Comparisons were made using separate non-parametric tests. RESULTS Thirty-six persons (24 male, 12 female) with PD (22 fallers, 14 non-fallers) participated. Only the FGA was able to detect differences between fallers and non-fallers for both ON/OFF medication testing. The predictive validity of the FGA and the TUG for fall identification was higher during OFF medication compared to ON medication testing. The predictive validity of the FGA was higher than the TUG and the Pull test during ON and OFF medication testing. DISCUSSION In order to most accurately identify fallers, clinicians should test persons with PD in ecologically relevant conditions and tasks. In this study, interpretation of the OFF medication performance and use of the FGA provided more accurate prediction of those who would fall.

Eccentric exercise versus Usual-care with older cancer survivors: The impact on muscle and mobility- an exploratory pilot study

BackgroundResistance exercise programs with high compliance are needed to counter impaired muscle and mobility in older cancer survivors. To date outcomes have focused on older prostate cancer survivors, though more heterogeneous groups of older survivors are in-need. The purpose of this exploratory pilot study is to examine whether resistance exercise via negative eccentrically-induced work (RENEW) improves muscle and mobility in a diverse sample of older cancer survivors.MethodsA total of 40 individuals (25 female, 15 male) with a mean age of 74 (± 6) years who have survived (8.4 ± 8 years) since their cancer diagnosis (breast, prostate, colorectal and lymphoma) were assigned to a RENEW group or a non-exercise Usual-care group. RENEW was performed for 12 weeks and measures of muscle size, strength, power and mobility were made pre and post training.ResultsRENEW induced increases in quadriceps lean tissue average cross sectional area (Pre: 43.2 ± 10.8 cm2; Post: 44.9 ± 10.9 cm2), knee extension peak strength (Pre: 248.3 ± 10.8 N; Post: 275.4 ± 10.9 N), leg extension muscle power (Pre: 198.2 ± 74.7 W; Post 255.5 ± 87.3 W), six minute walk distance (Pre: 417.2 ± 127.1 m; Post 466.9 ± 125.1 m) and a decrease on the time to safely descend stairs (Pre: 6.8 ± 4.5 s; Post 5.4 ± 2.5 s). A significant (P < 0.05) group x time interaction was noted for the muscle size and mobility improvements.ConclusionsThis exploration of RENEW in a heterogeneous cohort of older cancer survivors demonstrates increases in muscle size, strength and power along with improved mobility. The efficacy of a high-force, low perceived exertion exercise suggests RENEW may be suited to older individuals who are survivors of cancer.Trial RegistrationClinicalTrials.gov Identifier: NCT00335491

Eccentric Exercise in Rehabilitation: Safety, Feasibility and Application

This nonexhaustive mini-review reports on the application of eccentric exercise in various rehabilitation populations. The two defining properties of eccentric muscle contractions--a potential for high muscle-force production at an energy cost that is uniquely low--are revisited and formatted as exercise countermeasures to muscle atrophy, weakness, and deficits in physical function. Following a dual-phase implementation, eccentric exercise that induces rehabilitation benefits without muscle damage, thereby making it both safe and feasible in rehabilitation, is described. Clinical considerations, algorithms of exercise progression, and suggested modes of eccentric exercise are presented.

Measurement instruments to assess posture, gait, and balance in Parkinson's disease: Critique and recommendations

Disorders of posture, gait, and balance in Parkinsons disease (PD) are common and debilitating. This MDS‐commissioned task force assessed clinimetric properties of existing rating scales, questionnaires, and timed tests that assess these features in PD.

Intramuscular fat and inflammation differ in older adults: The impact of frailty and inactivity

ObjectivesIntramuscular adipose tissue (IMAT) is recognized as a negative predictor of both muscle and mobility function in older adults, however the mechanism by which IMAT may negatively influence muscle and mobility function is currently unknown. The release of pro-inflammatory cytokines from IMAT provides a potential reason for these negative associations. To explore this hypothesis we compared IMAT and muscular inflammation in age-and BMI-matched older non-obese frail and non-frail adults. We also sought to examine the relationship between IMAT and inflammation, and muscle and mobility function in this group of older adults.DesignA case-control sampling was used for this study. Age-and BMI-matched non-obese frail and non-frail individuals (<65 years) were recruited.MeasurementsMRI was used to quantify thigh IMAT and lean tissue. Unilateral muscle biopsies were used to quantify muscular inflammation as represented by interleukin-6 (IL-6) and tumor-necrosis factor alpha (TNF-α). Muscle and mobility function was also measured using a maximal voluntary isometric contraction, six-minute walk, and self-selected gait speed.Participants26 older (80.7 +/− 5.4 years) individuals (8 frail and 18 non-frail) were enrolled.ResultsThe frail-group had increased IMAT (p<0.01) and decreased lean tissue (p<0.01), and elevated IL-6 muscle mRNA (p=0.02) and IL-6 protein content (p=0.02) compared to the non-frail group. IMAT was significantly associated with IL-6 mRNA (r=0.43, p=.04) and protein expression within the muscle (r=0.41, p= 0.045). IL-6 mRNA was significantly associated with six-minute walk (r=−0.63, p<0.01), and gait speed (r=−0.60, p <0.01) and IL-6 protein was significantly associated with muscle force (r=−0.54, p=0.01), six-minute walk (r=−0.66, p<0.01), and gait speed (r=−0.76, p<0.01). No significant relationships were found for any variables with TNF-α.ConclusionNon-obese, older, frail individuals have increased IMAT and muscular inflammation when compared to their non-frail, age- and BMI-matched peers. A significant relationship exists between IMAT and muscle IL-6 expression as well as between IL-6 and muscle and mobility function of these older adults. This IMAT-inflammatory pathway provides a potential link between IMATs and decreased muscle and mobility function.

The feasibility and efficacy of eccentric exercise with older cancer survivors: A preliminary study

Introduction:Older individuals who have survived cancer and the commensurate treatment often experience a reduced quality of life in part due to their impaired muscular abilities and deficits in mobility. The purpose of this preliminary study was to determine the feasibility and preliminary efficacy of resistance exercise via negative, eccentrically induced work (RENEW) with older cancer survivors. Methods:Older cancer survivors with a perception of moderate muscle weakness and fatigue participated in 12 weeks of RENEW. Measures of feasibility included (1) the participants ability to progress the total amount of work of RENEW; (2) whether peak knee extension torque production became impaired; and (3) whether RENEW induced leg muscle pain as measured on a visual analog scale. The preliminary measure of efficacy included the performance of a timed up-and-go mobility test. Results:The participants significantly increased the total average work per week over the 12 weeks of RENEW. Participants increased (P < .001) their work approximately 3-fold from week 3 (7.6 [5.1] kJ) to week 12 (22.1 [14.8] kJ) without muscle pain over the 12-week RENEW training period. Knee extension peak torque production improved (11%) significantly (P = .02) (pretest: 248 [92] N; posttest: 275 [99] N) after 12 weeks of RENEW. The time to perform the up-and-go test improved (14%) significantly (P < .001) (pretest: 8.4 [2.7]; posttest: 7.2 [2.3] s) after 12 weeks of RENEW, suggesting preliminary efficacy. Conclusion:Collectively, RENEW appears feasible and potentially efficacious for older, weak, and fatigued cancer survivors. Implications for Cancer Survivors:The use of eccentric muscle exercise may be ideally suited for older cancer survivors due to its high force and low energetic-cost capabilities

Regional Muscle and Whole-Body Composition Factors Related to Mobility in Older Individuals: A Review

PURPOSE To describe previously reported locomotor muscle and whole-body composition factors related to mobility in older individuals. METHODS A narrative review of the literature, including a combination of search terms related to muscle and whole-body composition factors and to mobility in older individuals, was carried out. Statistical measures of association and risk were consolidated to summarize the common effects between studies. RESULTS Fifty-three studies were reviewed. Muscle and whole-body factors accounted for a substantial amount of the variability in walking speed, with coefficients of determination ranging from 0.30 to 0.47. Muscle power consistently accounted for a greater percentage of the variance in mobility than did strength. Risks associated with high fat mass presented a minimum odds ratio (OR) of 0.70 and a maximum OR of 4.07, while the minimum and maximum ORs associated with low lean mass were 0.87 and 2.30 respectively. Whole-body and regional fat deposits accounted for significant amounts of the variance in mobility. CONCLUSION Muscle power accounts for a greater amount of the variance in the level of mobility in older individuals than does muscle strength. Whole-body fat accounts for a greater amount of the variance in level of mobility than does whole-body lean tissue. Fat stored within muscle also appears to increase the risk of a mobility limitation in older individuals.

Development of a Quantitative In-Shoe Measurement System for Assessing Balance: Sixteen-Sensor Insoles

This work presents the first phase in the development of an in-shoe sensor system designed to evaluate balance. Sixteen force-sensitive resistors were strategically mounted to a removable insole, and the bilateral outputs were recorded. The initial results indicate that these sensors are capable of detecting subtle changes in weight distribution, corresponding to the subjects ability to balance. Preliminary analysis of this data found a clear correlation between the ability to balance and the state of health of the subject