Abstracts of Current Literature.

Abstracts of current literature are written by assignment and are summary reports of published material, not critiques.

Depressive Symptoms and Physical Decline in Community-Dwelling Older Persons

Penninx BW, Guralnik JM, Ferrucci L, et al (Epidemiology, Demography, and Biometry Program, National Institute on Aging, Bethesda, Md; INRCA Geriatric Department, Florence, Italy), JAMA. 1998;279:1720-1726.

Although major depression is relatively rare in older people who are community-dwellers, depressed mood is more prevalent. Depressed mood has been associated with high utilization of health care services. This 4-year prospective cohort study explored whether depression, especially depressive symptoms, affects physical function using objective, performance-based tests. A total of 1,286 persons aged 71 years or older in two Iowa counties participated in the study.

Data were collected as part of the Established Populations for Epidemiological Studies of the Elderly (EPESE) supported by the US National Institute on Aging. Symptoms of depression were evaluated using the Center for Epidemiologic Studies Depression Scale (CES-D); a cut-off score of 20 offered a more restrictive classification of depressed mood and a higher accuracy for the diagnosis of major depression. Physical performance tests included standing balance (eg, side-by-side, semi-tandem, tandem foot placement), walking speed for 2.4 m at "normal pace," and 5 trials that tested the ability to rise from a chair without using the upper extremities. Other variables included age, sex, marital status, education, smoking status, alcohol intake, body mass index, and blood pressure. Physical disability was evaluated by self-reports of difficulty in mobility according to the Roson-Breslan Scale.

The results of this study indicated that baseline depression scores ranged from 0 to 53, with a mean score of 9.2 and a standard deviation of 7.8. At baseline, 11% of the subjects were considered to have a depressed mood because they scored above the cutoff of 20 on the CES-D. The subjects who were depressed had significantly lower baseline performance scores than subjects who were not depressed. The subjects who were depressed at baseline also had a significantly greater decrease in performance scores over the 4-year period compared with the subjects who were not depressed. Further analysis of these data indicated that subjects who were depressed were 1.55 times more likely to experience a meaningful decline in physical performance over the 4 years of this study.

According to the researchers, this study supplied evidence that depressive symptoms in older persons foreshadowed a later decline in physical performance. The researchers stated that the results of this study were compatible with earlier studies that indicated that depression and poor physical function are "mutually reinforcing, causing a progressive downward spiral in the physical and psychological health of older persons" (p 1725). Therefore, the authors of this study believe that treatment of depressed mood may help reduce decline in physical performance in older persons.

Caren Betz, PT, GCS
NovaCare Rehabilitation at Hays Nursing Center
San Marcos, Tex

Lumbar Supports and Education for the Prevention of Low Back Pain in Industry

Van Poppel MN, Koes BW, van der Ploeg T, et al (Institute for Research in Extramural Medicine and the Faculty of Movement Sciences, Vrije University; Department of Health, Safety, and Environment, KLM Royal Dutch Airlines, Amsterdam, the Netherlands), JAMA. 1998;279:1789-1794.

The authors conducted a randomized, controlled trial in the Netherlands to determine the effectiveness of lumbar supports (LS) and education in the prevention of low back pain (LBP) in industry. All workers in the cargo department of a Dutch airline whose job description included manual material handling were invited to participate. A total of 312 workers were randomly placed into 1 of 4 groups: group 1 received both the lumbar support and education; group 2 received only education; group 3 received only the support; and group 4, the control group, received no intervention. Education consisted of lifting instruction that occurred over 3 sessions totaling 5 hours during a 12-week period. The lifting instructions included group training and individualized advice given at the workplace while workers were handling cargo. The lumbar support used in this study had adjustable elastic side pulls with Velcro fasteners and flexible stays and were kept in place with an anchor belt. Subjects who were given a lumbar support were instructed to wear the support at all times, and to tighten the side pulls for stronger support when performing strenuous tasks. The supports were worn for 6 months.

At baseline, subjects were given a questionnaire to determine their LBP history. Their answers fell into the following categories: never had LBP, LBP in the past (but not in the past year), LBP in the past year (but not at baseline), and LBP at baseline. At 6 months, subjects answered another questionnaire reporting any occurrence of LBP or sick leave because of LBP as well as the number of days with LBP and the number of days lost due to LBP during the intervention period.

The trunk-muscle strength of subjects who wore the support was evaluated at baseline and at 6 months. Abdominal strength was tested statically and dynamically, whereas back extensor strength was tested statically. Differences in outcome between the 4 groups were tested at the 6-month follow-up using the following tests: a chi-square test for experiences with LBP and use of sick leave, nonparametric testing for number of days with LBP and use of sick leave, and a t test for age and scores on muscle tests.

No significant differences were found in the 4 groups with respect to the main outcome measures: incidence of LBP, incidence of sick leave due to LBP, number of days with LBP, and number of days lost due to LBP. However, in a subgroup analysis of subjects with LBP at baseline, those subjects who wore the lumbar support had a lower incidence of LBP than those who did not. With respect to muscle strength, there were no significant differences in those individuals who used the support versus those who did not.

Based on the results of the study, the authors recommended against the use of lumbar supports or education (in the form used in this study) for the prevention of LBP. However, they concluded that the results of the subgroup analysis need to be confirmed by future research.

Gaetano Lombardo, PT, OCS
Long Island University
Brooklyn, NY

Biochemistry and Biomechanics of Healing Tendon, Part I: Effects of Rigid Plaster Casts and Functional Casts

Stehno-Bittel L, Reddy GK, Gum S, Enwemeka CS (Department of Physical Therapy Education, University of Kansas Medical Center, Kansas City, Kan), Med Sci Sports Exerc. 1998;30:788-793.

Weight-bearing activities and early joint mobility generally tend to facilitate normal healing and reduce muscle atrophy in lower-extremity injuries; however, after surgery, patients with an Achilles tendon rupture are traditionally immobilized at the ankle for 6 to 8 weeks, a treatment that can produce a variety of complications. This study compared certain biochemical and biomechanical parameters in the Achilles tendons of rabbits following an experimental tenotomy and immobilization by functional or rigid plaster casts.

Twenty nine-rabbits, aged 10 to 12 weeks, were used in this study. Each rabbit underwent an Achilles tendon transection at approximately 1.5 cm above the calcaneal attachment in the right lower extremity, followed by a resuturing of the tendon using a published protocol. Before full recovery from anesthesia, an experimental group of 15 rabbits were immobilized at the ankle in functional polyurethane casts, and a control group of 14 rabbits were similarly immobilized in rigid plaster casts. All of the immobilized limbs were placed in full plantar flexion and 90% knee flexion. The basic dimensions of all casts were identical except for their weight--a polyurethane cast weighed half that of a plaster cast. The functional casts allowed 15% of plantar flexion and 5% of inversion at the ankle. The rabbits were kept and observed in their cages for 14 days after surgery, where they moved around freely and received food and water routinely. On day 15, all of the casts were removed, and the rabbits were weighed and then euthanized. The healed Achilles tendons were harvested from each rabbit, weighed, and stored for subsequent biochemical and biomechanical analyses.

In the biochemical assays, the total collagen was quantified indirectly by measuring the hydroxyproline concentration in samples of the Achilles tendons using a protocol previously published by these authors. The cross-linking of collagen strands in the tendons was also studied by quantification of the hydroxypyridinium cross-links. In the biomechanical studies, the cross-section of each excised tendon and the force required to re-rupture the tendons at the transection region were determined. The latter was performed on an Instron apparatus, with the collected data representing such parameters as the load, displacement, stress, strain, elasticity, and absorbed energy of the tendon preparations. Statistical treatment of the data consisted of MANOVAs that compared of the biochemical and biomechanical features of tendons in each group.

During the 15 days of the study, the rabbits that had been placed in rigid casts lost 6.3% of their body weight, whereas those wearing functional casts lost only 0.4%. The biochemical properties of the tendons showed significant differences between the 2 groups. There was 60% more collagen and there were fewer cross-links in the tendons of the experimental group compared with those in the control group. There was no significant difference in the cross-sections of the tendons at the healing zone, regardless of the group designations. During the biomechanical studies, all tendons were pulled to rupture at the tenotomy region; however, there were between-group differences concerning some of the biomechanical parameters tested. The tendons that had been immobilized in functional casts required a 20% increase in the maximum load and a 21% increase in the maximum stress to rupture the tendons in comparison with those in the control group.

According to the researchers, the results of this study suggest that, in the experimental animals, immobilization of limbs by functional casts improves some biochemical and biomechanical aspects of healing tendons, both at the molecular level and at the tissue level. The authors noted that postsurgical functional casting appears to improve healing without incurring significant risks of re-rupture. Although the clinical significance and relevance of these findings await further research, the authors believe that this study introduces a new and useful concept for clinical practice.

Kamran Tavakol, PhD, PT
Howard University
Washington, DC

A Randomized Controlled Evaluation of Low-Intensity Laser Therapy: Plantar Fasciitis

Basford JR, Malanga GA, Krause DA, Harmsen WS (Department of Physical Medicine and Rehabilitation and Department of Epidemiology and Biostatistics, Mayo Clinic, Rochester, Minn; Kessler Institute of Rehabilitation, West Orange, NJ), Arch Phys Med Rehabil. 1998;79:249-254.

The purpose of this study was to systematically investigate the use of a 30-mW, .83-[micro] m gallium-aluminum-arsenide (GaAlAs) laser in the treatment of plantar fasciitis. This treatment modality has been used in other countries over the past 30 years and is gaining popularity in clinical use overseas. Scientific support for its efficacy, however, remains mixed. "Laser therapy" results in a slight temperature increase, however, laser therapy alters cellular processes in ways that are not explained by this heating alone. Most clinicians use infrared (IR) or helium-neon lasers, although studies suggest that the non-visible IR offers more effective tissue penetration. This deeper penetration may be necessary for treatment of deeper musculoskeletal injuries. The qualities of the 30-mW, .83-[micro]m GaAlAs laser allow blinded assignment of subjects to treatment or control groups.

Thirty-two individuals with a diagnosis of plantar fasciitis were recruited for the study. The inclusion criteria included male or female patients between the ages of 18 and 70 years who had had plantar fasciitis in one or both feet for more than 30 days. A diagnosis of plantar fasciitis was made on the basis of tenderness at the origin of the plantar fascia on the midanterior inferior border of the calcaneus bone and complaints of sharp, shooting, or localized inferior foot pain that worsened with activity or rising in the morning. A physician examined all patients to rule out other possible diagnoses and to find possible mechanical foot dysfunction. Subjects were excluded if they had been treated by a physician, physical therapist, or chiropractor within the past 30 days, if there were recent changes in activity levels, or if glucocorticoids were being used for any reason. In order to be included in the study, female subjects must have been postmenopausal or practicing effective means of birth control. The use of foot orthoses, non-steroidal anti-inflammatory drugs, and simple analgesics was permitted, but these factors were tracked throughout the study.

Subjects were block-randomized into 2 groups. Each group received an identical introduction to plantar fasciitis and home treatment from a therapist who was not aware of the group assignments. Treatment consisted of cleansing the most symptomatic foot, then providing 30-mW, continuous-wave, .83-[micro]m GaAlAs IR-diode laser treatment for 33 seconds over the origin of the plantar fascia, and 2 continuous sweeps of the laser lasting 33 seconds each along the medial border of the plantar fascia. The control group was treated in the same manner with a nonenergized probe. Treatment occurred 3 times per week for 4 weeks.

An evaluation was performed prior to the 1st treatment, after the 6th session, after the final (12th) session, and at a 1-month follow-up. A physician who was not aware of the group assignments asked questions about pain with the first steps in the morning, pain duration, effect of pain on daily activities, medication use, side effects from treatment, and use of orthoses. A visual analog scale (VAS) (0 mm=no pain, 1,000 mm=incredibly severe pain) was used to rate reports of pain during palpation, toe walking, and windlass testing. Subjects were also asked to compare pain levels to previous evaluations over the course of treatment. All but one of the subjects completed at least 11 of the 12 treatments and were evaluated at the intended intervals during treatment; 28 of the patients also returned for a 1-month follow-up evaluation.

Control and treatment group responses were compared throughout the course of treatment using the rank sum test for continuous variables (VAS ratings). Fisher's exact test for ordered outcome was used for the windlass test results. Baseline results were compared with the final results using a matched analysis (rank sum test on change scores). Measurements were fit in an overall model to compare rates of improvement between the treatment and placebo groups. The generalized-estimating-equations (GEE) model was used to account for possible correlations in the observations.

The findings indicated that the groups did not differ significantly by sex, activity level, or use of medications and orthoses. In addition the study did not find any significant difference between the groups in severity of morning pain and duration of pain on arising and during examination. The GEE model results were not reported because of the lack of difference between the 2 groups.

The authors concluded that the use of low-intensity laser therapy for the treatment of plantar fasciitis using this protocol was safe but not effective. They discussed the possible reasons for the lack of a treatment effect, including appropriateness of wavelength, dosage, and protocol parameters. However, the authors reported using parameters commonly used clinically in the treatment of plantar fasciitis. They suggested that further research with higher intensity and duration would be beneficial.

Karen McCulloch, PT, NCS
University of North Carolina
at Chapel Hill
Chapel Hill, NC