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Physical Therapy in Persons With Osteoarthritis
Osteoarthritis Supplement
Physical Therapy in Persons With Osteoarthritis Rachel Brakke, MD, Jaspal Singh, MD, William Sullivan, MD Abstract: Osteoarthritis (OA) is a leading cause of musculoskeletal pain and disability. According to a study by Lawrence et al, an estimated 27 million Americans were living with OA in 2008. This number will continue to increase as the population of persons older than 65 years grows. Because of the increasing number of persons who have this chronic condition that causes pain and decreases function, the prevalence of this diagnosis in primary care and musculoskeletal clinics likely will increase. The reduction of pain and improvement in function should be goals of providers who treat these patients. Physical therapy (PT) is a commonly used treatment modality for persons with OA. Many treatment modalities are available within the scope of PT, including strength training, manual therapy, aquatic therapy, electrical stimulation, and balance and perturbation training. A review of the most recent and highest-quality literature regarding these modalities found that strength training, aquatic therapy, and balance and perturbation therapy were the most beneficial with respect to reducing pain and improving function. Evidence clearly indicates that electrical stimulation likely has very little impact on these variables, and evidence regarding manual therapy is equivocal. Literature reviewing prognostic indicators for persons with OA who will likely respond to PT reveal that persons with milder disease (ie, unilateral OA, symptoms for less than 1 year, and a 40-m self-paced walking test of less than 25.9 seconds) and those who have pain of 6 or greater on the numerical pain rating scale are likely to have better outcomes with PT, which suggests that earlier referral is preferable. Barriers to the acceptance of PT as a therapeutic treatment for OA include fatalistic patient and provider perspectives, inadequate analgesia, and a fear among some patients and providers that increased activity will lead to progression of their OA. PM R 2012;4:S53-S58
INTRODUCTION Osteoarthritis (OA) is a leading cause of musculoskeletal pain and disability, and according to a study by Lawrence et al [1], an estimated 27 million Americans were living with OA in 2008. This number will continue to grow as the population of persons who are older than 65 years increases. Therefore it is important that practitioners who treat patients with OA fully understand all of the treatments available and are familiar with the relevant literature. Physical therapy (PT) is a treatment that is used commonly to decrease the pain and disability associated with OA. Multiple PT modalities commonly used for persons with OA are available to the referring provider, including strength training, electrical stimulation, manual therapy, aquatic therapy, and balance and perturbation therapy. (Taping and orthotics, which also are commonly used PT modalities, will be covered in other articles in this supplement.) In this article, we made an effort to review the highest-quality evidence available for each of the modalities listed. Studies were included only if they assessed outcomes such as pain and/or function. Literature assessing prognostic indicators for persons with OA who respond well to PT is discussed, and individualized versus group therapy is evaluated as to determine whether, despite cost savings, a group environment can be just as effective as individual therapy. Finally, identified barriers to PT in this population are discussed to enhance the likelihood of compliance with PT referrals. PM&R 1934-1482/12/$36.00 Printed in U.S.A.
R.B. Department of Physical Medicine and Rehabilitation, University of Colorado School of Medicine, Mail Stop F-493, 12631 East 17th Ave, Academic Office 1, Room 2513, Aurora, CO 80045. Address correspondence to: R.B.; e-mail: [email protected] Disclosure: nothing to disclose J.S. Department of Physical Medicine and Rehabilitation, University of Colorado School of Medicine, Aurora, CO Disclosure: nothing to disclose W.S. Department of Physical Medicine and Rehabilitation, University of Colorado School of Medicine, Aurora, CO Disclosure: nothing to disclose Disclosure Key can be found on the Table of Contents and at www.pmrjournal.org
© 2012 by the American Academy of Physical Medicine and Rehabilitation Vol. 4, S53-S58, May 2012 DOI: 10.1016/j.pmrj.2012.02.017
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STRENGTH TRAINING Strength training is a commonly used therapy modality for patients with OA. It has been found that persons with knee OA demonstrate weaker quadriceps muscles than do persons without OA [2]. Natural history studies have demonstrated that patients with knee OA who have more quadriceps strength have less pain and functional limitations [3]. A systematic review published in 2008 by Lange et al [4] evaluated the role of strength training in patients with OA. In this review, the authors examined 18 randomized controlled trials and found that resistance training improved muscle strength, reduced pain, and improved physical function measures in 50%-75% of cohorts. We also will review 2 key randomized controlled trials that evaluate strength training in patients with OA. In the first study published in 2006, Mikesky et al [5] evaluated the effect of quadriceps and hamstring strength training on the incidence and progression of knee OA. These investigators specifically evaluated the impact of strength training versus range of motion exercises on functional measures (ie, Western Ontario and McMaster Universities OA Index [WOMAC] and Short Form-36 [SF-36]), lower extremity strength, and radiographic progression of OA. The “control” group in this study was the range of motion group. Exercises were performed 3 times per week for 12 weeks and then followed by a 12-month home program. All clinical and functional measures were assessed at baseline and at 12, 18, and 24 months. A total of 221 older adults were enrolled in this study and were stratified on the basis of gender, radiographic evidence of knee OA, and severity of knee pain. Both the strength training and range of motion groups lost quadriceps strength during the course of this study (30 months). However, it was noted that persons in the strength training group lost less strength than did persons in the range of motion group, although this difference was not statistically significant. Also, the strength training OA group demonstrated a decreased rate of joint space narrowing on radiographic images during the 30-month study period compared with the range of motion group, although this finding was not statistically significant (18% versus 28% progression; P ⫽ .094). No significant changes in the functional measures (WOMAC or SF-36) were found in either group. A limitation of this study was that there was no true control group, as it could be argued that persons in the range of motion group were exposed to an element of strength training. In another study, investigators evaluated the effect of a home-based strength training program in older adults with knee OA [6]. This study assessed 46 older adults (55 years or older) with knee OA and randomly assigned them to either a standardized home-based progressive strength training program designed for persons with knee OA or a nutrition education intervention. The primary outcomes were the
PHYSICAL THERAPY IN OSTEOARTHRITIS
WOMAC index of pain and physical function subscales, and secondary outcomes included the clinical knee examination, muscle strength, physical performance measures, and a quality-of-life questionnaire. Persons randomly assigned to the strength training group showed a 71% improvement in knee extension strength versus 3% improvement in the education group (P ⬍ .01). Participants reported that pain and function improved by 36% and 38%, respectively, in the strengthening group relative to the education group (11% and 21%). Persons in the strengthening group also showed a significant decrease in pain level (a 43% mean reduction compared with control subjects) and a 44% improvement in physical function compared with control subjects. These 2 studies support strength training as a valid intervention for persons with knee OA because it increases strength, reduces pain, and improves function. Additional research has been conducted in which investigators studied whether certain types of strengthening exercises are preferred over others. These studies have not demonstrated specific benefits of high versus low resistance training [7] and dynamic versus isometric resistance training [8]. From the available evidence, it can be concluded that strength training is beneficial.
ELECTRICAL STIMULATION Electrical stimulation is a commonly used modality in PT. Several randomized controlled trials have assessed its efficacy in persons with OA. A Cochrane review of transcutaneous electrostimulation for OA of the knee performed in 2009 examined a total of 18 small trials that included a total of 813 patients [9]. Eleven of the trials used transcutaneous electrical nerve stimulation (TENS), 4 used interferential current stimulation, 1 used both TENS and interferential current stimulation, and 2 used pulsed electrostimulation. Overall, the studies included were small and the methodological quality was poor, with a high degree of heterogeneity among the trials. The conclusion by the Cochrane group was that the use of electrical stimulation was not effective in the reduction of pain. Other small studies have essentially confirmed the findings of the 2009 Cochrane review group. The first of these studies was published in Arthritis and Rheumatism and examined the effect of pulsed electrical stimulation versus placebo on pain (Visual Analog Scale), function, and joint stiffness measures of the WOMAC and quality of life (SF-36) in patients with knee OA [10]. This study found no added benefit of electrical stimulation on pain or function compared with the placebo group. In another randomized, controlled trial, investigators evaluated the effect of a group of participants with knee OA undergoing strengthening exercises [11]. This group was then divided into 3 subgroups: TENS unit and exercise, placebo TENS and exercise, or exercise only. The results
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demonstrated increased quadriceps activation in the TENS with exercise group compared with the other 2 groups that did not have a TENS unit at 4 weeks. However, the WOMAC scores improved in all groups without a significant difference between the subgroups. A third study evaluated 30 women with mild to moderate OA of the knee and compared the effects of 4 weeks of electrical stimulation (12 sessions total) versus no treatment on quadriceps muscle strength, function (WOMAC), and a timed walk [12]. Muscle strength, WOMAC, and timed walk were assessed at baseline, 5 weeks, and 16 weeks after enrollment. No statistical improvement was found in any of the measures tested at any of the time points. Collectively, this evidence suggests that electrical stimulation may have a minimal benefit in helping patients with OA gain activation in targeted muscle groups, but there is no indication that large improvements are seen in pain or function compared with use of a placebo.
MANUAL THERAPY Manual therapy is another commonly used treatment modality in which the joints or muscles of patients are manipulated with the intention of restoring the range of motion of the joint or increasing the flexibility of the muscles around the joint. A recent study showed that mobilization of the osteoarthritic carpometacarpal joints in elderly patients decreased pain in the carpometacarpal joint; however, it did not improve function in these patients [13]. A recent systematic review of manual therapy studies in patients with knee and hip OA found only 4 randomized and controlled studies that fit the inclusion criteria [14]. In this review, French et al concluded that manual therapy has benefits compared with exercise therapy in the reduction of pain in persons with hip OA in the short and long term. Despite this assertion, the strongest study included in this systematic review demonstrated an improvement in the Visual Analog Scale of only 9 points of 100 in the short term and 7 points of 100 in the long term, which is not considered to be a clinically significant change. Because of the small number of randomized controlled trials and patients included in these studies, this finding is fairly inconclusive, and no definitive assertion can be made regarding this modality. The other 3 studies were highly biased and had only minimal effect on pain or function. On the basis of these studies, manual therapy shows only a small reduction in pain compared with placebo.
AQUATIC THERAPY Aquatic therapy appears to have a positive effect on persons with OA. Lim et al [15] compared the effect of an aquatic exercise program versus a land-based program versus placebo on knee function and body fat composition in obese
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patients with OA. Patients in the exercise groups participated in exercise interventions 3 times a week for 8 weeks. The outcome measures assessed included body fat analysis, brief pain inventory, WOMAC, SF-36, and knee isokinetic strength tests. The aquatic therapy group showed significant improvements in pain, disability, and quality of life relative to the placebo group. Reduction in pain interference with activity was greater in the aquatic therapy group than in the land-based group. Both exercise groups showed significant improvements in WOMAC disability compared with the control group. This study concludes that aquatic therapy more effectively reduces the impact of pain on exercise capacity and suggests that obese patients with more severe OA or higher levels of pain may benefit from starting out with aquatic therapy. Another study evaluated the benefit of aquatic therapy versus no intervention for persons with symptomatic hip or knee OA [16]. In this randomized controlled trial, participants in the intervention group received 6 weeks of twiceweekly aquatic PT. The control group was told to continue with their usual activities and medications and not to start a new exercise regimen during the 6-week study period. Outcome measures included pain, physical function, physical activity levels, quality of life, and muscle strength. Seventytwo percent of aquatic therapy participants reported a global improvement in pain and 75% reported a global improvement in function compared with 17% for both measures in the control group. The aquatic therapy group also reported significant improvements in pain and physical function relative to the control group. Benefits were maintained through the 6 weeks, and 84% of participants continued with aquatic therapy independently between the completion of the intervention at 6 weeks and the reassessment at 12 weeks. These benefits were largely maintained during the 12-week study period. A third study evaluated aquatic therapy versus gymbased therapy versus a control intervention in patients with OA [17]. This study found that both gym-based and aquatic therapies improved strength and function in persons with OA compared with persons who participated in the nonexercise control group. The aquatic therapy group demonstrated a significant improvement in distance walked and the physical component of the SF-12 compared with the control group. The compliance rates were similar for both aquatic and gym-based therapy, although it was slightly higher for the aquatic therapy group (84% versus 75%). This study demonstrates little difference between therapy groups but significant differences between the collective exercise group (gym-based and aquatic) in multiple outcome measures compared with the nonexercise control group. This study suggests that assessing the patient’s preference for gym-based versus aquatic therapy may be the key in distinguishing which type of therapy would be best for each particular patient,
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because this assessment would likely influence compliance rates. Although participants in this study worked individually with therapists in the water or in the gym, it is likely that patients could easily transition to independent exercise with a tailored home program in the water or in the gym based on their preference. In conclusion, evidence supports aquatic therapy as a valid intervention for persons with OA to reduce pain and improve function, especially in obese patients and persons who favor this setting over a gym-based model.
BALANCE/PERTURBATION THERAPY Another commonly used PT modality is perturbation and balance therapy, which is thought to enhance balance and agility, thus allowing patients to navigate functional challenges more readily. A recent study published by Fitzgerald et al [18] examined the addition of agility and perturbation training techniques to therapy for persons with knee OA. In this study, participants with knee OA were randomly assigned to either an exercise-only group or an exercise and perturbation training group. The perturbation training group received a number of exercises designed to enhance forward, backward, and side balance. The primary outcome measure was the WOMAC score, and the secondary outcome measures were self-reported knee instability, knee pain, global rating of change score (GRCS), and the Get Up and Go test score. The results showed an overall improvement in both groups but no significant improvement in any of the outcome measures tested at the 1-year time point for persons in the perturbation group. Some short-term improvements were noted in the perturbation group with respect to the WOMAC total and physical function scores and GRCS in the early follow-up period. In the second study, investigators evaluated women with knee OA and compared 2 exercise groups: strengthening exercises with kinesthesia and balance exercises versus strengthening exercises only [19]. Both groups received 8 weeks of therapy and were tested at baseline and at the completion of the therapy. The investigators examined WOMAC, SF-36, and 10 stairs climbing, and 10-m walking times. Additive effects of kinesthesia and balance exercises were noted with respect to improvement in the physical function measures of the WOMAC and SF-36, isokinetic muscle strength of the quadriceps and hamstring muscles, and 10-stairs climbing and 10-m walking times. Both groups showed overall improvement in pain and function. In brief, this study demonstrated an additive benefit of the kinesthesia and balance training in persons with knee OA. On the basis of this study, a practitioner may consider requesting that a therapist address balance and perturbation therapies in addition to strengthening for patients with lower extremity OA because they appear to have an additive benefit.
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PROGNOSTIC INDICATORS AND PATIENT PERSPECTIVE Although PT generally is considered a cost-effective therapy, it still results in a significant cost if multiple therapy sessions are requested in a one-on-one outpatient therapy model. Therefore it is imperative to accurately determine who would most likely participate and benefit from individualized PT that is tailored to a patient’s biomechanical deficits versus patients who may benefit from a generalized program or even group exercise. In one preliminary study, Wright et al [20] evaluated the effect of several clinical variables on the post-test probability of response to therapy in persons with hip OA. This study was part of a larger study to examine the efficacy of various types of PT treatments in patients with knee and hip OA. In this randomized trial, participants received manual therapy, exercise therapy, or a combination of exercise, and manual therapy versus usual care. The outcome measures assessed included the percent and absolute change in pain, function, and GRCS over 1 year. The GRCS is a measure in which participants rate their symptoms at a 12-month follow-up and assess their overall progress relative to baseline. This study identified 5 criteria that enhanced post-test probability of improvement with therapy, including unilateral hip pain, age younger than 58 years, pain of 6 or higher on the numeric pain rating scale, duration of symptoms for less than a year, and a 40-m self-paced walking test of less than 25.9 seconds. The pretest probability of a positive response to PT was calculated at 32% when all patients were evaluated. Patients with only one of the aforementioned factors also had a post-test probability of a favorable response to PT at 32%. For persons with 2 variables, the post-test probability increased from 32% to 65%, and for persons with 3 or more of the aforementioned features, an increase in post-test probability of a positive response increased from 32% to 99%. This research stands alone in evaluating clinical factors that can be assessed in a single clinic visit that might help distinguish patients who will favorably respond to PT. This study’s limitations included a small sample size (91 participants completed the study and were included in the analysis) and the fact that participants were randomly allocated to different therapies. This allocation may differ from clinical practice, in which therapies are chosen to address specific deficits manifested by patients. Despite these drawbacks, this study is an important pilot study of prognostic indicators that might distinguish patients who will respond to therapy.
BARRIERS TO PT In evaluating efficacy of therapy in persons with OA, it is helpful to realize common barriers to participating in therapy as cited by patients. A case study evaluating a focus group of patients (11), general practitioners (7), and physical thera-
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pists (10) regarding knee OA demonstrated several potential barriers to patients’ effective engagement with PT [21]. First, both patients and general practitioners reported fatalistic opinions about the eventual progression of this disease process and the limited treatment modalities available. Second, patients believed that engaging in general activity such as PT was difficult unless adequate analgesia had been achieved with medications. Third, most patients with knee OA were unaware of the benefit of exercise and did not believe that regular exercise was required beyond their activities of daily living. The general practitioners interviewed were mixed in their opinions regarding the benefit of activity for patients with knee OA, with some reporting that increased activity would cause an increase in arthritis progression and others believing it was beneficial. This study gives important insight into the general impressions of patients and some physicians. To increase compliance with a PT referral, it is first important to explain to patients the overall improvement in function and pain that accompanies increased activity through PT and low-impact exercise. Patient compliance also may be enhanced by achieving adequate analgesia before beginning a therapy program.
INDIVIDUAL VERSUS GROUP THERAPY The cost efficacy of therapy in the treatment of OA is an important consideration. Literature on this topic, in which investigators compare PT with other types of treatments such as surgical or medication management, is scarce. Questions also exist regarding the efficacy and cost of individual versus group therapy. One study of patients older than 50 years who had chronic knee pain and presumed OA evaluated the WOMAC function and pain at baseline and at 12 months along with several other secondary measures such as pain, objective functional performance, anxiety, depression, health care use, and exercise-related health beliefs [22]. Patients who were randomly assigned to usual therapy received, on average, 4 sessions (up to a maximum of 10 sessions) of one-on-one therapy. The intervention group received a total of 10 sessions of 60 minutes each in a group setting that included up to 6 participants and also had 15 to 20 minutes of education followed by 40 minutes of circuit training with exercises designed to address common deficits associated with knee pain. These patients also were given a home exercise program and were encouraged to perform the exercises 3 times per week for the duration of the study. They also received an additional session 4 months after completing the initial 10 sessions. Both groups demonstrated similar improvements in clinical outcomes (WOMAC function and pain and all of the secondary outcome measures previously listed), with the exception of exercise-related health beliefs, which improved more in the group therapy subset. Despite no significant
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differences in pain or function between the 2 interventions, the group therapy participants cost the health care system less (£320) over the course of the year than did the traditional therapy group (£ 583). Although this study generally supports group therapy in a small setting as a possible alternative to individual therapy, the population in this study was all inclusive of persons with chronic knee pain and was not limited to persons with OA. In addition, the amount of exposure to treatment time was far greater in the group setting, which likely contributed to the favorable outcomes in this group.
CONCLUSIONS This review evaluated the evidence behind some of the common PT practices used in the OA population. On the basis of the literature, a few take-home points can be made. First, providers should ensure that they adequately treat pain associated with OA before sending patients to therapy sessions. Second, many patients and providers are under the impression that more activity will likely lead to an inevitable progression of their OA and pain. Adequate education about the importance of movement and strengthening to improve function and reduce pain may be beneficial in improving patient compliance with this treatment plan. Third, several factors improve the patient’s responsiveness to PT, including pain for less than 1 year, age younger than 58 years, unilateral symptoms, and pain greater than or equal to 6 on the numerical pain rating scale. Although patients do not need to have all of the aforementioned characteristics to respond well to PT, the more of these that that they demonstrate, the more likely they will benefit from this intervention. Of all of these factors, the one we can control as clinicians is the timeliness of the referral to PT. Evidence shows that the most beneficial therapy modalities related to OA are strengthening, aquatic therapy, and balance and perturbation therapies. Although some persons may argue that exercise alone would be sufficient for these patients, it should be noted that in all of the studies discussed here, patients had very close supervision by a physical therapist after a diagnosis had been determined. Although some studies included group instruction, the importance of having a trained therapist who knows the patient’s diagnosis and baseline ability guide patients through a program cannot be understated.
REFERENCES 1. Lawrence R, Felson D, Helmick C, et al. Estimates of the prevalence of arthritis and other rheumatic conditions in the United States—Part II. Arthritis Rheum 2008;58:26-35. 2. Palmieri-Smith R, Thomas A, Karvonen-Guiterrez C, Sowers M. Isometric quadriceps strength in women with mild, moderate and severe knee osteoarthritis. Am J Phys Med Rehabil 2010;89:541-548. 3. Amin S, Baker K, Niu J, et al. Quadriceps strength and the risk of cartilage loss and symptom progression in knee osteoarthritis. Arthritis Rheum 2009;60:189-198.
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4. Lange A, Vanwanseele B, Singh F. Strength training for treatment of osteoarthritis of the knee: A systematic review. Arthritis Rheum 2008; 59:1488-1494. 5. Mikesky A, Mazzuca S, Brandt K, Perkins S, Damush T, Lane K. Effects of strength training on the incidence and progression of knee osteoarthritis. Arthritis Rheum 2006;55:690-699. 6. Baker K, Nelson M, Felson D, Layne J, Sarno R, Roubenoff R. The efficacy of home based progressive strength training in older adults with knee osteoarthritis: A randomized controlled trial. J Rheumatol 2001; 28:1655-1665. 7. Jan M, Lin J, Liau J, Lin Y, Lin D. Investigation of clinical effects of highand low-resistance training for patients with knee osteoarthritis: A randomized controlled trial. Phys Ther 2008;88:427-436. 8. Topp R, Woolley S, Hornyak J, Khuder S, Kahaleh B. The effect of dynamic versus isometric resistance training on pain and functioning among adults with osteoarthritis of the knee. Arch Phys Med Rehabil 2002;83:1187-1195. 9. Rutjes A, Nuesch E, Kalichman L, et al. Transcutaneous electrostimulation for osteoarthritis of the knee. Cochrane Database Systematic Rev 2009;7:CD002823. 10. Fary R, Carroll G, Briffa T, Briffa N. The effectiveness of pulsed electrical stimulation in the management of osteoarthritis of the knee: Results of a double-blind, randomized, placebo-controlled, repeatedmeasures trial. Arthritis Rheum 2011;63:1333-1342. 11. Pietrosimone B, Saliba S, Hart J, Hertel J, Kerrigan D, Ingersoll C. Effects of transcutaneous electrical nerve stimulation and therapeutic exercise on quadriceps activation in people with tibiofemoral osteoarthritis. J Orthop Sports Phys Ther 2011;41:4-12. 12. Palmieri-Smith R, Thomas A, Karvonen-Guiterrez C, Sowers M. Isometric quadriceps strength in women with mild, moderate and severe knee osteoarthritis. Am J Phys Med Rehabil 2010;541-548. 13. Villafane J, Silva G, Diaz-Parreno S, Fernandez-Carnero J. Hypoalgesic and motor effects of kaltenborn mobilization on elderly patients with
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14.
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secondary thumb carpometacarpal osteoarthritis: A randomized controlled trial. J Manipulative Physiol Ther 2011;34:547-556. French H, Brennan A, White B, Cusack T. Manual therapy for osteoarthritis of the hip or knee—A systematic review. Man Ther 2011;16: 109-117. Lim JY, Tchai E, Jang S. Effectiveness of aquatic exercise for obese patients with knee osteoarthritis: A randomized controlled trial. PMR 2010;2:723-731. Hinman R, Heywood S, Day A. Aquatic physical therapy for hip and knee osteoarthritis: Results of a single-blind randomized controlled trial. Phys Ther 2007;87:32-43. Foley A, Halbert J, Hewitt T, Crotty M. Does hydrotherapy improve strength and physical function in patients with osteoarthritis: A randomized controlled trial comparing a gym based and a hydrotherapy based strengthening programme. Ann Rheum Dis 2003;62: 1162-1167. Fitzgerald G, Piva S, Gil A, Wisiniewski S, Oddis C, Irrgang J. Agility and perturbation training techniques in exercise therapy for reducing pain and improving function in people with knee osteoarthritis: A randomized clinical trial. Phys Ther 2011;91:452-469. Diracoglu D, Aydin R, Baskent A, Celik A. Effects of kinesthesia and balance exercises in knee osteoarthritis. J Clin Rheumatol 2005;11: 303-310. Wright A, Cook C, Flynn T, Baxter G, Abbott J. Predictors of response to physical therapy intervention in patients with primary hip osteoarthritis. Phys Ther 2011;91:510-523. Poitras S, Rossignol M, Avouac J, et al. Management recommendations for knee osteoarthritis: How usable are they? Joint Bone Spine 2010; 77:458-465. Jessep S, Walsh N, Ratcliffe J, Hurley M. Long-term clinical benefits and costs of an integrated rehabilitation programme compared with outpatient physiotherapy for chronic knee pain. Physiotherapy 2009;95:94102.
Physical Therapy in Persons With Osteoarthritis Rachel Brakke, MD, Jaspal Singh, MD, William Sullivan, MD Abstract: Osteoarthritis (OA) is a leading cause of musculoskeletal pain and disability. According to a study by Lawrence et al, an estimated 27 million Americans were living with OA in 2008. This number will continue to increase as the population of persons older than 65 years grows. Because of the increasing number of persons who have this chronic condition that causes pain and decreases function, the prevalence of this diagnosis in primary care and musculoskeletal clinics likely will increase. The reduction of pain and improvement in function should be goals of providers who treat these patients. Physical therapy (PT) is a commonly used treatment modality for persons with OA. Many treatment modalities are available within the scope of PT, including strength training, manual therapy, aquatic therapy, electrical stimulation, and balance and perturbation training. A review of the most recent and highest-quality literature regarding these modalities found that strength training, aquatic therapy, and balance and perturbation therapy were the most beneficial with respect to reducing pain and improving function. Evidence clearly indicates that electrical stimulation likely has very little impact on these variables, and evidence regarding manual therapy is equivocal. Literature reviewing prognostic indicators for persons with OA who will likely respond to PT reveal that persons with milder disease (ie, unilateral OA, symptoms for less than 1 year, and a 40-m self-paced walking test of less than 25.9 seconds) and those who have pain of 6 or greater on the numerical pain rating scale are likely to have better outcomes with PT, which suggests that earlier referral is preferable. Barriers to the acceptance of PT as a therapeutic treatment for OA include fatalistic patient and provider perspectives, inadequate analgesia, and a fear among some patients and providers that increased activity will lead to progression of their OA. PM R 2012;4:S53-S58
INTRODUCTION Osteoarthritis (OA) is a leading cause of musculoskeletal pain and disability, and according to a study by Lawrence et al [1], an estimated 27 million Americans were living with OA in 2008. This number will continue to grow as the population of persons who are older than 65 years increases. Therefore it is important that practitioners who treat patients with OA fully understand all of the treatments available and are familiar with the relevant literature. Physical therapy (PT) is a treatment that is used commonly to decrease the pain and disability associated with OA. Multiple PT modalities commonly used for persons with OA are available to the referring provider, including strength training, electrical stimulation, manual therapy, aquatic therapy, and balance and perturbation therapy. (Taping and orthotics, which also are commonly used PT modalities, will be covered in other articles in this supplement.) In this article, we made an effort to review the highest-quality evidence available for each of the modalities listed. Studies were included only if they assessed outcomes such as pain and/or function. Literature assessing prognostic indicators for persons with OA who respond well to PT is discussed, and individualized versus group therapy is evaluated as to determine whether, despite cost savings, a group environment can be just as effective as individual therapy. Finally, identified barriers to PT in this population are discussed to enhance the likelihood of compliance with PT referrals. PM&R 1934-1482/12/$36.00 Printed in U.S.A.
R.B. Department of Physical Medicine and Rehabilitation, University of Colorado School of Medicine, Mail Stop F-493, 12631 East 17th Ave, Academic Office 1, Room 2513, Aurora, CO 80045. Address correspondence to: R.B.; e-mail: [email protected] Disclosure: nothing to disclose J.S. Department of Physical Medicine and Rehabilitation, University of Colorado School of Medicine, Aurora, CO Disclosure: nothing to disclose W.S. Department of Physical Medicine and Rehabilitation, University of Colorado School of Medicine, Aurora, CO Disclosure: nothing to disclose Disclosure Key can be found on the Table of Contents and at www.pmrjournal.org
© 2012 by the American Academy of Physical Medicine and Rehabilitation Vol. 4, S53-S58, May 2012 DOI: 10.1016/j.pmrj.2012.02.017
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STRENGTH TRAINING Strength training is a commonly used therapy modality for patients with OA. It has been found that persons with knee OA demonstrate weaker quadriceps muscles than do persons without OA [2]. Natural history studies have demonstrated that patients with knee OA who have more quadriceps strength have less pain and functional limitations [3]. A systematic review published in 2008 by Lange et al [4] evaluated the role of strength training in patients with OA. In this review, the authors examined 18 randomized controlled trials and found that resistance training improved muscle strength, reduced pain, and improved physical function measures in 50%-75% of cohorts. We also will review 2 key randomized controlled trials that evaluate strength training in patients with OA. In the first study published in 2006, Mikesky et al [5] evaluated the effect of quadriceps and hamstring strength training on the incidence and progression of knee OA. These investigators specifically evaluated the impact of strength training versus range of motion exercises on functional measures (ie, Western Ontario and McMaster Universities OA Index [WOMAC] and Short Form-36 [SF-36]), lower extremity strength, and radiographic progression of OA. The “control” group in this study was the range of motion group. Exercises were performed 3 times per week for 12 weeks and then followed by a 12-month home program. All clinical and functional measures were assessed at baseline and at 12, 18, and 24 months. A total of 221 older adults were enrolled in this study and were stratified on the basis of gender, radiographic evidence of knee OA, and severity of knee pain. Both the strength training and range of motion groups lost quadriceps strength during the course of this study (30 months). However, it was noted that persons in the strength training group lost less strength than did persons in the range of motion group, although this difference was not statistically significant. Also, the strength training OA group demonstrated a decreased rate of joint space narrowing on radiographic images during the 30-month study period compared with the range of motion group, although this finding was not statistically significant (18% versus 28% progression; P ⫽ .094). No significant changes in the functional measures (WOMAC or SF-36) were found in either group. A limitation of this study was that there was no true control group, as it could be argued that persons in the range of motion group were exposed to an element of strength training. In another study, investigators evaluated the effect of a home-based strength training program in older adults with knee OA [6]. This study assessed 46 older adults (55 years or older) with knee OA and randomly assigned them to either a standardized home-based progressive strength training program designed for persons with knee OA or a nutrition education intervention. The primary outcomes were the
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WOMAC index of pain and physical function subscales, and secondary outcomes included the clinical knee examination, muscle strength, physical performance measures, and a quality-of-life questionnaire. Persons randomly assigned to the strength training group showed a 71% improvement in knee extension strength versus 3% improvement in the education group (P ⬍ .01). Participants reported that pain and function improved by 36% and 38%, respectively, in the strengthening group relative to the education group (11% and 21%). Persons in the strengthening group also showed a significant decrease in pain level (a 43% mean reduction compared with control subjects) and a 44% improvement in physical function compared with control subjects. These 2 studies support strength training as a valid intervention for persons with knee OA because it increases strength, reduces pain, and improves function. Additional research has been conducted in which investigators studied whether certain types of strengthening exercises are preferred over others. These studies have not demonstrated specific benefits of high versus low resistance training [7] and dynamic versus isometric resistance training [8]. From the available evidence, it can be concluded that strength training is beneficial.
ELECTRICAL STIMULATION Electrical stimulation is a commonly used modality in PT. Several randomized controlled trials have assessed its efficacy in persons with OA. A Cochrane review of transcutaneous electrostimulation for OA of the knee performed in 2009 examined a total of 18 small trials that included a total of 813 patients [9]. Eleven of the trials used transcutaneous electrical nerve stimulation (TENS), 4 used interferential current stimulation, 1 used both TENS and interferential current stimulation, and 2 used pulsed electrostimulation. Overall, the studies included were small and the methodological quality was poor, with a high degree of heterogeneity among the trials. The conclusion by the Cochrane group was that the use of electrical stimulation was not effective in the reduction of pain. Other small studies have essentially confirmed the findings of the 2009 Cochrane review group. The first of these studies was published in Arthritis and Rheumatism and examined the effect of pulsed electrical stimulation versus placebo on pain (Visual Analog Scale), function, and joint stiffness measures of the WOMAC and quality of life (SF-36) in patients with knee OA [10]. This study found no added benefit of electrical stimulation on pain or function compared with the placebo group. In another randomized, controlled trial, investigators evaluated the effect of a group of participants with knee OA undergoing strengthening exercises [11]. This group was then divided into 3 subgroups: TENS unit and exercise, placebo TENS and exercise, or exercise only. The results
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demonstrated increased quadriceps activation in the TENS with exercise group compared with the other 2 groups that did not have a TENS unit at 4 weeks. However, the WOMAC scores improved in all groups without a significant difference between the subgroups. A third study evaluated 30 women with mild to moderate OA of the knee and compared the effects of 4 weeks of electrical stimulation (12 sessions total) versus no treatment on quadriceps muscle strength, function (WOMAC), and a timed walk [12]. Muscle strength, WOMAC, and timed walk were assessed at baseline, 5 weeks, and 16 weeks after enrollment. No statistical improvement was found in any of the measures tested at any of the time points. Collectively, this evidence suggests that electrical stimulation may have a minimal benefit in helping patients with OA gain activation in targeted muscle groups, but there is no indication that large improvements are seen in pain or function compared with use of a placebo.
MANUAL THERAPY Manual therapy is another commonly used treatment modality in which the joints or muscles of patients are manipulated with the intention of restoring the range of motion of the joint or increasing the flexibility of the muscles around the joint. A recent study showed that mobilization of the osteoarthritic carpometacarpal joints in elderly patients decreased pain in the carpometacarpal joint; however, it did not improve function in these patients [13]. A recent systematic review of manual therapy studies in patients with knee and hip OA found only 4 randomized and controlled studies that fit the inclusion criteria [14]. In this review, French et al concluded that manual therapy has benefits compared with exercise therapy in the reduction of pain in persons with hip OA in the short and long term. Despite this assertion, the strongest study included in this systematic review demonstrated an improvement in the Visual Analog Scale of only 9 points of 100 in the short term and 7 points of 100 in the long term, which is not considered to be a clinically significant change. Because of the small number of randomized controlled trials and patients included in these studies, this finding is fairly inconclusive, and no definitive assertion can be made regarding this modality. The other 3 studies were highly biased and had only minimal effect on pain or function. On the basis of these studies, manual therapy shows only a small reduction in pain compared with placebo.
AQUATIC THERAPY Aquatic therapy appears to have a positive effect on persons with OA. Lim et al [15] compared the effect of an aquatic exercise program versus a land-based program versus placebo on knee function and body fat composition in obese
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patients with OA. Patients in the exercise groups participated in exercise interventions 3 times a week for 8 weeks. The outcome measures assessed included body fat analysis, brief pain inventory, WOMAC, SF-36, and knee isokinetic strength tests. The aquatic therapy group showed significant improvements in pain, disability, and quality of life relative to the placebo group. Reduction in pain interference with activity was greater in the aquatic therapy group than in the land-based group. Both exercise groups showed significant improvements in WOMAC disability compared with the control group. This study concludes that aquatic therapy more effectively reduces the impact of pain on exercise capacity and suggests that obese patients with more severe OA or higher levels of pain may benefit from starting out with aquatic therapy. Another study evaluated the benefit of aquatic therapy versus no intervention for persons with symptomatic hip or knee OA [16]. In this randomized controlled trial, participants in the intervention group received 6 weeks of twiceweekly aquatic PT. The control group was told to continue with their usual activities and medications and not to start a new exercise regimen during the 6-week study period. Outcome measures included pain, physical function, physical activity levels, quality of life, and muscle strength. Seventytwo percent of aquatic therapy participants reported a global improvement in pain and 75% reported a global improvement in function compared with 17% for both measures in the control group. The aquatic therapy group also reported significant improvements in pain and physical function relative to the control group. Benefits were maintained through the 6 weeks, and 84% of participants continued with aquatic therapy independently between the completion of the intervention at 6 weeks and the reassessment at 12 weeks. These benefits were largely maintained during the 12-week study period. A third study evaluated aquatic therapy versus gymbased therapy versus a control intervention in patients with OA [17]. This study found that both gym-based and aquatic therapies improved strength and function in persons with OA compared with persons who participated in the nonexercise control group. The aquatic therapy group demonstrated a significant improvement in distance walked and the physical component of the SF-12 compared with the control group. The compliance rates were similar for both aquatic and gym-based therapy, although it was slightly higher for the aquatic therapy group (84% versus 75%). This study demonstrates little difference between therapy groups but significant differences between the collective exercise group (gym-based and aquatic) in multiple outcome measures compared with the nonexercise control group. This study suggests that assessing the patient’s preference for gym-based versus aquatic therapy may be the key in distinguishing which type of therapy would be best for each particular patient,
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because this assessment would likely influence compliance rates. Although participants in this study worked individually with therapists in the water or in the gym, it is likely that patients could easily transition to independent exercise with a tailored home program in the water or in the gym based on their preference. In conclusion, evidence supports aquatic therapy as a valid intervention for persons with OA to reduce pain and improve function, especially in obese patients and persons who favor this setting over a gym-based model.
BALANCE/PERTURBATION THERAPY Another commonly used PT modality is perturbation and balance therapy, which is thought to enhance balance and agility, thus allowing patients to navigate functional challenges more readily. A recent study published by Fitzgerald et al [18] examined the addition of agility and perturbation training techniques to therapy for persons with knee OA. In this study, participants with knee OA were randomly assigned to either an exercise-only group or an exercise and perturbation training group. The perturbation training group received a number of exercises designed to enhance forward, backward, and side balance. The primary outcome measure was the WOMAC score, and the secondary outcome measures were self-reported knee instability, knee pain, global rating of change score (GRCS), and the Get Up and Go test score. The results showed an overall improvement in both groups but no significant improvement in any of the outcome measures tested at the 1-year time point for persons in the perturbation group. Some short-term improvements were noted in the perturbation group with respect to the WOMAC total and physical function scores and GRCS in the early follow-up period. In the second study, investigators evaluated women with knee OA and compared 2 exercise groups: strengthening exercises with kinesthesia and balance exercises versus strengthening exercises only [19]. Both groups received 8 weeks of therapy and were tested at baseline and at the completion of the therapy. The investigators examined WOMAC, SF-36, and 10 stairs climbing, and 10-m walking times. Additive effects of kinesthesia and balance exercises were noted with respect to improvement in the physical function measures of the WOMAC and SF-36, isokinetic muscle strength of the quadriceps and hamstring muscles, and 10-stairs climbing and 10-m walking times. Both groups showed overall improvement in pain and function. In brief, this study demonstrated an additive benefit of the kinesthesia and balance training in persons with knee OA. On the basis of this study, a practitioner may consider requesting that a therapist address balance and perturbation therapies in addition to strengthening for patients with lower extremity OA because they appear to have an additive benefit.
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PROGNOSTIC INDICATORS AND PATIENT PERSPECTIVE Although PT generally is considered a cost-effective therapy, it still results in a significant cost if multiple therapy sessions are requested in a one-on-one outpatient therapy model. Therefore it is imperative to accurately determine who would most likely participate and benefit from individualized PT that is tailored to a patient’s biomechanical deficits versus patients who may benefit from a generalized program or even group exercise. In one preliminary study, Wright et al [20] evaluated the effect of several clinical variables on the post-test probability of response to therapy in persons with hip OA. This study was part of a larger study to examine the efficacy of various types of PT treatments in patients with knee and hip OA. In this randomized trial, participants received manual therapy, exercise therapy, or a combination of exercise, and manual therapy versus usual care. The outcome measures assessed included the percent and absolute change in pain, function, and GRCS over 1 year. The GRCS is a measure in which participants rate their symptoms at a 12-month follow-up and assess their overall progress relative to baseline. This study identified 5 criteria that enhanced post-test probability of improvement with therapy, including unilateral hip pain, age younger than 58 years, pain of 6 or higher on the numeric pain rating scale, duration of symptoms for less than a year, and a 40-m self-paced walking test of less than 25.9 seconds. The pretest probability of a positive response to PT was calculated at 32% when all patients were evaluated. Patients with only one of the aforementioned factors also had a post-test probability of a favorable response to PT at 32%. For persons with 2 variables, the post-test probability increased from 32% to 65%, and for persons with 3 or more of the aforementioned features, an increase in post-test probability of a positive response increased from 32% to 99%. This research stands alone in evaluating clinical factors that can be assessed in a single clinic visit that might help distinguish patients who will favorably respond to PT. This study’s limitations included a small sample size (91 participants completed the study and were included in the analysis) and the fact that participants were randomly allocated to different therapies. This allocation may differ from clinical practice, in which therapies are chosen to address specific deficits manifested by patients. Despite these drawbacks, this study is an important pilot study of prognostic indicators that might distinguish patients who will respond to therapy.
BARRIERS TO PT In evaluating efficacy of therapy in persons with OA, it is helpful to realize common barriers to participating in therapy as cited by patients. A case study evaluating a focus group of patients (11), general practitioners (7), and physical thera-
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pists (10) regarding knee OA demonstrated several potential barriers to patients’ effective engagement with PT [21]. First, both patients and general practitioners reported fatalistic opinions about the eventual progression of this disease process and the limited treatment modalities available. Second, patients believed that engaging in general activity such as PT was difficult unless adequate analgesia had been achieved with medications. Third, most patients with knee OA were unaware of the benefit of exercise and did not believe that regular exercise was required beyond their activities of daily living. The general practitioners interviewed were mixed in their opinions regarding the benefit of activity for patients with knee OA, with some reporting that increased activity would cause an increase in arthritis progression and others believing it was beneficial. This study gives important insight into the general impressions of patients and some physicians. To increase compliance with a PT referral, it is first important to explain to patients the overall improvement in function and pain that accompanies increased activity through PT and low-impact exercise. Patient compliance also may be enhanced by achieving adequate analgesia before beginning a therapy program.
INDIVIDUAL VERSUS GROUP THERAPY The cost efficacy of therapy in the treatment of OA is an important consideration. Literature on this topic, in which investigators compare PT with other types of treatments such as surgical or medication management, is scarce. Questions also exist regarding the efficacy and cost of individual versus group therapy. One study of patients older than 50 years who had chronic knee pain and presumed OA evaluated the WOMAC function and pain at baseline and at 12 months along with several other secondary measures such as pain, objective functional performance, anxiety, depression, health care use, and exercise-related health beliefs [22]. Patients who were randomly assigned to usual therapy received, on average, 4 sessions (up to a maximum of 10 sessions) of one-on-one therapy. The intervention group received a total of 10 sessions of 60 minutes each in a group setting that included up to 6 participants and also had 15 to 20 minutes of education followed by 40 minutes of circuit training with exercises designed to address common deficits associated with knee pain. These patients also were given a home exercise program and were encouraged to perform the exercises 3 times per week for the duration of the study. They also received an additional session 4 months after completing the initial 10 sessions. Both groups demonstrated similar improvements in clinical outcomes (WOMAC function and pain and all of the secondary outcome measures previously listed), with the exception of exercise-related health beliefs, which improved more in the group therapy subset. Despite no significant
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differences in pain or function between the 2 interventions, the group therapy participants cost the health care system less (£320) over the course of the year than did the traditional therapy group (£ 583). Although this study generally supports group therapy in a small setting as a possible alternative to individual therapy, the population in this study was all inclusive of persons with chronic knee pain and was not limited to persons with OA. In addition, the amount of exposure to treatment time was far greater in the group setting, which likely contributed to the favorable outcomes in this group.
CONCLUSIONS This review evaluated the evidence behind some of the common PT practices used in the OA population. On the basis of the literature, a few take-home points can be made. First, providers should ensure that they adequately treat pain associated with OA before sending patients to therapy sessions. Second, many patients and providers are under the impression that more activity will likely lead to an inevitable progression of their OA and pain. Adequate education about the importance of movement and strengthening to improve function and reduce pain may be beneficial in improving patient compliance with this treatment plan. Third, several factors improve the patient’s responsiveness to PT, including pain for less than 1 year, age younger than 58 years, unilateral symptoms, and pain greater than or equal to 6 on the numerical pain rating scale. Although patients do not need to have all of the aforementioned characteristics to respond well to PT, the more of these that that they demonstrate, the more likely they will benefit from this intervention. Of all of these factors, the one we can control as clinicians is the timeliness of the referral to PT. Evidence shows that the most beneficial therapy modalities related to OA are strengthening, aquatic therapy, and balance and perturbation therapies. Although some persons may argue that exercise alone would be sufficient for these patients, it should be noted that in all of the studies discussed here, patients had very close supervision by a physical therapist after a diagnosis had been determined. Although some studies included group instruction, the importance of having a trained therapist who knows the patient’s diagnosis and baseline ability guide patients through a program cannot be understated.
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