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Special Issue |
Clinical Specialty Experts
(Orthopaedic Surgeon), American Academy of Orthopaedic Surgeons, USA
(Internist, Rheumatologist), American College of Physicians, USA
(Physiatrist)
(Internist), University of Pennsylvania, Philadelphia. USA
(Neurologist), American Academy of Neurology, USA
(Physical Therapist), American Physical Therapy Association, USA
(Physical Therapist), American College of Rheumatology, Association of Health Professionals, USA
(Physiatrist), American Academy of Physical Medicine and Rehabilitation, USA
(Internist), Cochrane Back Group, USA
(Family Practice), American Academy of Family Physicians, USA
Ottawa Methods Group
(Public Health, specialization in epidemiology); Career Scientist, Ministry of Ontario Health (Canada), and Assistant Professor, Physiotherapy Program, School of Rehabilitation Sciences, University of Ottawa, Ottawa, Ontario, Canada
(Epidemiology), Chair, Centre for Global Health, Institute of Population Health, Ottawa, Ontario, Canada
(Epidemiology and Biostatistics), Professor and Chairman, Department of Epidemiology and Community Medicine, University of Ottawa, Ottawa, Ontario, Canada
(Kinesiology), Research Associate, Clinical Epidemiology Unit, Ottawa Health Research Institute, Ottawa Hospital, Civic Campus, Ottawa, Ontario, Canada
(Medical Sociology), Medical Research Council Scholar, Clinical Epidemiology Unit, Ottawa Health Research Institute, Ottawa Hospital, Civic Campus, Ottawa, Ontario, Canada
(Epidemiology), Research Associate, Department of Medicine, University of Ottawa and Clinical Epidemiology Unit, Ottawa Health Research Institute, Ottawa Hospital, Civic Campus, Ottawa, Ontario, Canada
Research Fellow, Ottawa Hospital, General Campus, Ottawa, Ontario, Canada
Director of the Medical Library, Ottawa Hospital, Ottawa, Ontario, Canada
Research Associate, Department of Medicine, Clinical Epidemiology Unit, Ottawa Health Research Institute, Ottawa Hospital, Civic Campus, Ottawa, Ontario, Canada
Program of Physiotherapy, School of Rehabilitation Sciences, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada
Address all correspondence and requests for reprints to: Peter Tugwell, MD, MSc, Chair, Centre for Global Health, Institute of Population Health, 1 Stewart St, Rm 312, Ottawa, Ontario, Canada K1N 6N5 (ptugwell{at}uottawa.ca)
| Abstract |
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Key Words: Clinical practice guidelines Evidence-based practice Knee Meta-analysis Physical therapy Practitioner feedback survey Rehabilitation Systematic reviews
| INTRODUCTION |
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Prospective studies show that knee pain improves with time, regardless of therapy. The most common practice for general practitioners is a referral for a variable number of sessions of physical therapy. There is a need to provide clinicians with evidence for informed decision making regarding treatment options.
The Philadelphia Panel was convened to evaluate 8 selected rehabilitation interventions for knee pain: thermotherapy, therapeutic massage, therapeutic exercises, electromyographic (EMG) biofeedback, ultrasound, transcutaneous electrical nerve stimulation (TENS), electrical stimulation, and combined rehabilitation interventions.
The purpose of this article is to describe the evidence-based clinical practice guidelines (EBCPGs) developed by the panel about rehabilitation interventions for knee pain. The aim of the developing the EBCPGs was to improve appropriate use of rehabilitation interventions for knee pain. The target users of these guidelines are physical therapists, physiatrists, orthopedic surgeons, rheumatologists, family physicians, and neurologists.
| METHODS |
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Studies were eligible if they were randomized controlled trials (RCTs), nonrandomized controlled clinical trials (CCTs), or case control or cohort studies that evaluated the intervention of interest in a population with knee conditions including chondromalacia patellae (patellofemoral syndrome), postsurgical conditions, knee osteoarthritis, and tendinitis. Rheumatoid arthritis was excluded. The types of patients seen postsurgery included those who had meniscectomy, total knee replacement, anterior cruciate ligament reconstruction, and arthroscopic surgery for removal of loose bodies or plica.
The outcomes of interest were defined by the Philadelphia Panel as functional status, pain, ability to work, patient global assessment, patient satisfaction, and quality of life. The interventions included massage, thermal therapy (hot or cold packs), electrical stimulation, EMG biofeedback, TENS, therapeutic ultrasound, therapeutic exercises, and combinations of these rehabilitation interventions. Studies where control groups received active treatments were not considered sufficient evidence for recommendations. Concurrent treatments were allowed if they were given in the same way to both the experimental and control groups (eg, home exercises, educational booklets, advice on posture). However, concurrent therapy that was given to one group but not the other group was not accepted (eg, education by means of lectures for the control group were not accepted). No limitations based on methodological quality were imposed. Only English-, French-, and Spanish-language articles were accepted. Abstracts were not included.
Although most of these knee conditions have pain as the primary outcome, patients with these conditions also seek physical therapy for limitations other than pain such as functional limitations, instability, and weakness. The Philadelphia Panel evaluated the effects of interventions on outcomes considered to be clinically meaningful and validated, as described in the accompanying methods paper ("Philadelphia Panel Evidence-Based Clinical Practice Guidelines on Selected Rehabilitation Interventions: Overview and Methodology"). Some outcomes such as flexibility and strength were not considered by the members of the Philadelphia Panel to be sufficient evidence to warrant a clinical recommendation. However, functional assessment, quality of life, and patient global assessment were considered sufficient for a recommendation and have been evaluated when reported in the trials. If other outcomes were available, the results are described in the sections titled "Efficacy."
A structured literature search was developed based on the sensitive search strategy for RCTs recommended by the Cochrane Collaboration1 and modifications proposed by Haynes et al.2 The search strategy was expanded to identify case control, cohort, and nonrandomized studies. The search was conducted in the electronic databases of MEDLINE, EMBASE, Current Contents, CINAHL, and the Cochrane Controlled Trials Register up to July 1, 2000. In addition, the registries of the Cochrane Field of Rehabilitation and Related Therapies and the Cochrane Musculoskeletal Group and the Physiotherapy Evidence Database (PEDro) were searched. The references of all included trials were searched for relevant studies. Content experts were contacted for additional studies.
Two independent reviewers (VAR, JP) appraised the titles and abstracts of the literature search, using a checklist with the a priori defined selection criteria. Relevant studies were retrieved and the full articles were assessed for inclusion by 2 independent reviewers. Data were extracted by 2 independent reviewers from included articles, using predetermined extraction forms regarding the population characteristics, details of the interventions, trial design, allocation concealment, and outcomes. Methodological quality was assessed with a 5-point validated scale that assigns 2 points each for randomization and double-blinding and 1 point for description of withdrawals.3,4 Differences in data extraction and quality assessment were resolved by consensus.
Data were analyzed at 3 approximate time points posttherapy: 1 month, 6 months, and 12 months. If outcomes were reported at different intervals, the closest time was used for these time points.
Because several etiologies of knee pain exist, different conditions were analyzed separately. Chondromalacia patellae (patellofemoral pain syndrome), postsurgical conditions, osteoarthritis, and tendinitis were analyzed separately.
| STATISTICAL ANALYSIS |
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To calculate clinical improvement (defined as 15% improvement relative to a control), the absolute benefit and the relative difference in the change from baseline were calculated. Absolute benefit was calculated as the improvement in the treatment group less the improvement in the control group, in the original units. Relative difference in the change from baseline was calculated as the absolute benefit divided by the baseline mean (weighted for the treatment and control groups). For dichotomous data, the relative percentage of improvement was calculated as the difference in the percentage of improvement in the treatment and control groups.
The recommendations were graded by their level of evidence (I or II) and by the strength of evidence (A, B, or C). This grading system is shown in Table 1 and is described more fully elsewhere (see article titled "Philadelphia Panel Evidence-Based Clinical Practice Guidelines on Selected Rehabilitation Interventions: Overview and Methodology"). Briefly, grade A recommendations indicate that a clinically important benefit was shown in one or more RCTs. Grade B recommendations were assigned for interventions with a clinically important benefit shown in nonrandomized trials. Because there is less confidence in the results of nonrandomized studies, grade B recommendations required that the study be assigned a quality score of 3 or more out of 5. Grade C recommendations were assigned to interventions that have been compared with a control and have shown no evidence of effect in controlled trials. A master grid showing each rehabilitation intervention assessed and the strength and level of evidence is presented in Table 2. The report follows the same order as this grid (from left to right, top to bottom) for these interventions for which eligible studies where found.
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| RESULTS |
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| PATELLOFEMORAL PAIN SYNDROME |
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Efficacy:
None demonstrated. There was no difference in number of patients who rated their knee pain as improved with continuous therapeutic ultrasound and ice therapy compared with ice alone (Fig. 2). There was a large loss to follow-up (45%, 19 of 42 patients).
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Clinical Recommendations Compared With Other Guidelines:
The Philadelphia Panel recommends that there is poor evidence to include or exclude therapeutic ultrasound alone (grade C for patient global assessment) as an intervention for patellofemoral pain syndrome.
| POSTSURGERY KNEE PAIN |
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Efficacy:
None demonstrated. The only outcome measure was a knee rating scale (0100) that measures pain, function, range of motion (ROM), muscle strength, flexion deformity, and instability. There was no difference in the knee rating between the usual care and strengthening exercise groups at 3, 12, 24, or 48 weeks postsurgery (Fig. 3).
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Clinical Recommendations Compared With Other Guidelines:
The Philadelphia Panel recommends that there is poor evidence to include or exclude preoperative strengthening exercises alone (grade C for pain and function) prior to unilateral knee arthroplasty surgery.
Thermotherapy for Postsurgery Knee Pain, Level I (RCT), Grade C for Pain (No Evidence of Clinically Important Benefit)
Summary of Trials:
One RCT (N=45) of cold gel packs in patients who had been prescribed home exercises after knee surgery was included.8
Efficacy:
None demonstrated. There was no difference after 1 week of therapy between cold packs and no cold pack therapy on the McGill Pain Scale (Fig. 4), for ROM or strength.
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Clinical Recommendations Compared With Other Guidelines:
The Philadelphia Panel recommends that there is poor evidence to include or exclude cryotherapy (grade C for pain) as an adjunct intervention to home exercises after knee surgery.
TENS for Postsurgery Rehabilitation, Level I (RCT), Grade C for Pain (No Evidence of Clinically Important Benefit)
Summary of Trials:
One RCT (N=90) of TENS (70 Hz) compared with placebo TENS and with a group that received no therapy was included.9
Efficacy:
None demonstrated. The trial demonstrated that there was no significant difference between TENS and placebo for pain, ROM, or muscle force. However, there was a significant benefit of TENS on pain relief compared with no therapy. The data from this trial cannot be presented graphically due to lack of data (standard deviations not reported).
Strength of Published Evidence in Comparison With Other Guidelines:
The Philadelphia Panel found good scientific evidence (level I, RCT) regarding TENS after knee surgery. Transcutaneous electrical nerve stimulation after knee surgery has not been assessed by other guidelines.
Clinical Recommendations Compared With Other Guidelines:
The Philadelphia Panel recommends that there is poor evidence to include or exclude TENS alone (grade C for pain) as an intervention after knee surgery.
| KNEE OSTEOARTHRITIS |
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Three RCTs (N=79) were excluded because no outcomes were included that met the Philadelphia Panel criteria for clinical importance and validity (strength outcomes only).1618 One RCT was excluded because manual therapy was used as the comparison intervention.19
Efficacy:
Clinically important benefit on pain and patient global assessment. Pain relief was 38% greater with strength exercises relative to placebo in one RCT (N=201).14 Similarly, pain relief was greater with strengthening exercises relative to untreated control groups by 16%,13 42%,12 and 78%10 (P<.05, Tab. 6, Fig. 5).
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One RCT of straight leg raises for knee osteoarthritis showed a clinically important improvement in function relative to a control (24%).15
Strength of Published Evidence in Comparison With Other Guidelines:
The Philadelphia Panel found level I (RCT) evidence that showed a clinically important benefit of strength exercises on knee osteoarthritis pain. The British Medical Journal (BMJ)21 guidelines reported that there was limited evidence of benefit, with few well-designed RCTs. They based this finding on 3 systematic reviews (with 1997 as the most recent search date) and 3 RCTs. The RCTs were excluded from the Philadelphia Panel systematic review because they did not include a placebo group (2 trials) or included manual therapy (1 trial).
Clinical Recommendations Compared With Other Guidelines:
The Philadelphia Panel recommends that there is good evidence to include strengthening, stretching, and functional exercises alone (grade A for pain and patient global assessment, grade C+ for function) as interventions for knee osteoarthritis pain. This recommendation agrees with American College of Rheumatology (ACR) guidelines for the management of osteoarthritis that recommend the use of ROM, strength exercise, and aerobic exercise.22 The BMJ guidelines21 based their results on a published meta-analysis14 and concluded that exercises are likely to be beneficial for both pain relief and function.
Practitioner Agreement
Practitioner Comments
Panel's Response:
Modifications based on individual needs were not described in the included trials and therefore cannot be addressed in this guideline. The Philadelphia Panel assessed only selected rehabilitation interventions. Furthermore, the Philadelphia Panel did not rank therapies, but rather evaluated whether the evidence supports the use of the interventions assessed when compared with no therapy or a placebo. The trial by Deyle et al19 was excluded because the intervention group received manual therapy.
Thermotherapy for Knee Osteoarthritis, Level I (RCT), Grade C for Pain (No Evidence of Clinically Important Benefit)
Summary of Trials:
One RCT (N=50) of ice massage versus a placebo for knee osteoarthritis was identified.23 The treatment was applied 5 times per week for 20 minutes each session for 2 weeks.
Efficacy:
None demonstrated. Ice massage of 4 acupoints (SP-9 yinlingquan, GB-34 yanglingquan, ST-34 liangqui, and ST-35 dubi) using a wood block was not different from placebo TENS for pain or stiffness relief (Tab. 8).
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Clinical Recommendations Compared With Other Guidelines:
The Philadelphia Panel recommends that there is poor evidence to include or exclude ice massage alone (grade C for pain) as an intervention for knee osteoarthritis.
Therapeutic Ultrasound for Knee Osteoarthritis, Level I (RCT), Grade C for Pain (No Evidence of Clinically Important Benefit)
Summary of Trials:
One RCT (N=74) of therapeutic ultrasound versus a placebo for knee osteoarthritis was identified.24 One CCT (N=120) was excluded because the comparison intervention was "galvanic current."25
Efficacy:
None demonstrated. The therapeutic ultrasound group reported less pain than the placebo group after 4 weeks of therapy, but the difference was not statistically significant (WMD=1.3 cm on a 10-cm VAS, 95% confidence interval [CI] = 0.07 to 2.7 cm). This difference corresponded to an 11% relative difference between groups in the change from baseline. At 3 months follow-up, there was no difference between groups.
Strength of Published Evidence in Comparison With Other Guidelines:
The Philadelphia Panel found good evidence (level I, RCT) of the effects of therapeutic ultrasound in knee osteoarthritis. Therapeutic ultrasound has not been assessed by other knee osteoarthritis guidelines.
Clinical Recommendations Compared With Other Guidelines:
The Philadelphia Panel recommends that there is poor evidence to include or exclude therapeutic ultrasound alone (grade C for pain) as an intervention for knee osteoarthritis.
TENS for Knee Osteoarthritis, Level I (RCT), Grade A for Pain and Patient Global Assessment (Clinically Important Benefit)
Summary of Trials:
Seven placebo-controlled RCTs (N=184) evaluated TENS versus a placebo for knee osteoarthritis.23,2631 Four RCTs were excluded due to inappropriate populations of patients with postsurgery knee conditions,9 myalgia,32 and low back pain.33 One RCT used of a non-TENS device, described as producing "pulsed electrical stimulation."34
Efficacy:
Clinically important benefit on pain and patient global assessment. Three RCTs (N= 87) demonstrated a significant difference in number of patients with pain improvement of 20% to 46% relative to the control group after 1 month of therapy30,31,35 (Tab. 9). Pain assessed by visual analog scale was statistically significantly improved in our meta-analysis of the 5 RCTs of greater than 3 weeks' duration. The pooled estimate was equivalent to an improvement in pain of 41% from baseline relative to placebo23 (Tab. 10, Fig. 7). The absolute change from baseline ranged from 57% to 83% of baseline in the TENS group. One RCT of the immediate effects of 30 minutes of TENS showed that there was no difference between TENS and placebo TENS on immediate pain relief.27 Three RCTs demonstrated clinically important and statistically significant improvements in patient-assessed overall improvement relative to a control of 29% at 1 month,29 17% at 1 month,28 and 48% at 3 months4 (Tab. 11, Fig. 8). Functional status was not assessed using validated measurement scales such as the Health Assessment Questionnaire (HAQ), Lee Index, WOMAC, or Arthritis Impact and Measurement Scale (AIMS) in any of the included trials.
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Clinical Recommendations Compared With Other Guidelines:
The Philadelphia Panel recommends that there is good evidence to include TENS as an intervention for pain associated with knee osteoarthritis (grade A for pain and patient global assessment).
Practitioner Agreement
Practitioner Comments
Panel's Response:
Practitioner agreement is lower than with other guidelines (73%), possibly because there is more conflicting evidence (ie, some trials showed no statistical significance). Specifically, the grade A rating was achieved only for patient global assessment, and the effect on pain was not statistically significant (grade C+). These guidelines do not rank interventions in comparison with each other, but rather indicate the efficacy when compared with a placebo. The Philadelphia Panel has also shown no effect of TENS on other types of chronic pain (eg, postsurgery knee pain, chronic low back pain). This difference in efficacy may relate to the method of TENS application. In particular, the trials that used low-frequency, high-intensity TENS on acupoints23,35 demonstrated the greatest benefit on pain and patient global assessment. Acupuncture-like TENS was not used in the trials of chronic low back pain. The EBCPGs have been modified to specify the length of follow-up in these trials. Benefit is specified for pain and patient global assessment, but not for functional status.
Electrical Stimulation for Knee Osteoarthritis, Level I (RCT), Grade C for Function (No Clinically Important Benefit Demonstrated)
Summary of Trials:
One RCT (N=30) of patterned neuromuscular electrical stimulation of the quadriceps femoris muscle in elderly patients with knee osteoarthritis was included.36
Efficacy:
None demonstrated. The timed sit-to-stand test and walking velocity were statistically significantly improved when compared with placebo stimulation. However, the percentage of change from baseline was less than 15%, thus not meeting the criteria for clinical relevance. The results cannot be displayed graphically because inadequate data were reported (standard deviations were printed in graphical format only). No strength outcomes were reported.
Strength of Published Evidence in Comparison With Other Guidelines:
The Philadelphia Panel found good evidence (level I, RCT) of the effects of electrical stimulation in knee osteoarthritis. Electrical stimulation has not been assessed by other knee osteoarthritis guidelines.
Clinical Recommendations Compared With Other Guidelines:
The Philadelphia Panel recommends that there is poor evidence to include or exclude electrical stimulation alone (grade C for function) as an intervention for knee osteoarthritis. Because electrical stimulation is usually used to improve strength, this recommendation is inconclusive until evidence of effects on strength have been shown in clinical trials.
| TENDINITIS |
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Efficacy:
None demonstrated. Pain while running was not different between groups that received massage and no treatment. A daily pain diary showed a clinically unimportant difference in pain of 8% between groups (Fig. 9).
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Clinical Recommendations Compared With Other Guidelines:
The Philadelphia Panel recommends that there is poor evidence to include or exclude deep friction massage alone (grade C for pain) as an intervention for iliotibial band syndrome.
Insufficient Evidence
Therapeutic exercises for knee tendinitis have been assessed in one RCT, but no validated, clinically relevant outcomes (as defined by the Philadelphia Panel) were measured.38
Electrical stimulation for the knee postsurgery has been compared with exercises and EMG biofeedback but has not been compared with a placebo with sufficient sample size.39
For chondromalacia patellae (patellofemoral pain syndrome), different types of therapeutic exercises (isokinetic, isometric, closed chain, open chain) have been compared.40 However, the only RCT with an untreated control group did not measure any outcomes of interest (ROM and strength only).41
After knee surgery, several types of therapeutic exercise have been compared: closed versus open kinetic chain,42 functional versus isometric exercises,43 and exercise versus electrical stimulation.18 However, there have been no comparisons with placebo (or untreated) control groups.
Electromyographic biofeedback after knee surgery lacks placebo-controlled trials.44,45
| DISCUSSION |
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The major implication of this work is that there is methodologically poor evidence to support the use of a number of widely accepted interventions. The trials identified were often inconclusive because of lack of a placebo group, use of nonvalidated outcomes, use of population diagnoses that are not widely applicable to the population, and inadequate sample size.
Within specific interventions, the characteristics of the intervention also may play a role in the lack of a clinically important benefit. For example, deep friction massage was evaluated for knee iliotibial tendinitis. However, several other forms of massage that are in use in practice (eg, effleurage, acupressure, trigger point therapy) have not been evaluated. As another example, therapeutic ultrasound for patellofemoral pain syndrome has been evaluated in a trial where all patients received ice. It is possible that therapeutic ultrasound alone would have beneficial effects compared with placebo therapeutic ultrasound. This highlights the need to investigate the specific mode of use that is used in clinical practice and most likely to show benefits.
The presence of home exercises as an adjunct intervention for many of these trials complicates the interpretation of results, particularly because the adherence to a program of home exercises is rarely reported in the trials. Differential adherence may confound the treatment effect.
The therapeutic application of several rehabilitation interventions is based on empirical experience.4648 Research on rehabilitation interventions is further complicated by the multitreatment model used in clinical practice. A patient usually receives several rehabilitation interventions in one session. Furthermore, the types of therapy will be chosen according to the phase of recovery. For example, the first phase of recovery for an acute injury is characterized by rest, ice, and compression. The second phase is characterized by stretching, mobility exercises, and electrotherapy such as therapeutic ultrasound or TENS to relieve pain and inflammation.46 The third phase involves strengthening, continued stretching, and continued use of electrotherapy for the breakup of scar tissue. The practice of rehabilitation requires a better theoretical basis49,50 and well-designed controlled research.51
The measurement of the effects of rehabilitation interventions is complex.52,53 Standardized measurement of outcomes is needed to facilitate scientific advances in clinical care for knee conditions.14,54 The Philadelphia Panel agreed that the primary outcomes of clinical importance are: pain, functional status, patient global assessment, quality of life, return to work, and patient satisfaction. Furthermore, the Philadelphia Panel required that these outcomes be measured with a scale whose measurements have established reliability and validity. Although pain is usually the primary outcome, other limitations such as reduced ROM, swelling, and muscle weakness and instability affect patients with various knee conditions. These limitations are sometimes the primary cause for physical therapist consultation. These limitations are captured by the Philadelphia Panel outcomes for functional status, patient global assessment, quality of life, and return to work.
Physical factors5557 and psychosocial factors20,58,59 have an impact on the effectiveness of rehabilitation interventions for knee pain. Because of these factors, a multidimensional clinical evaluation is recommended in knee pain management, especially among patients with osteoarthritis and rheumatoid arthritis.5860 It was not possible to examine these risk factors in this review.
Potential methodological biases could have been introduced in trials on effectiveness of rehabilitation interventions for the management of knee pain. A misclassification bias related to the knee condition studied is present with the lack of precise medical and physical therapy diagnoses observed.57,6166 Selection bias could have occurred with the presence of heterogeneity of clinical characteristics such as age, prevalent versus incident cases, stages of the disease, level of pain, and presence or absence of inflammation. However, differences in disease duration were minimized in these guidelines by excluding studies with a mix of acute and chronic conditions or mixed diagnoses. Characteristics of the device parameters and of the therapeutic application49 also could make a difference in the effect size. Publication bias may be a problem if only trials with positive findings have been published.67 The effect of publication bias could not be assessed because of the small number of trials. A language bias was introduced because the Philadelphia Panel reviewed only studies published in English, French, or Spanish.
The methodological quality of studies on knee pain rarely reached 3 out of 5 or greater on the Jadad scale3,4 (Appendix 2). Randomization (17/31 studies) was rarely fully adequate (ie, performed using computerized random number lists). Insufficient information was noted in several RCTs regarding the treatment assignment procedure. Inappropriate blinding (21/31 studies) also could lead to information bias. Blinding is an issue with physical rehabilitation interventions. Complete blinding is difficult to achieve because of visual and other sensory differences between treatment and placebo groups as well as unintended communication between patient and evaluator.68 The use of an unblinded, untreated control group can lead to an overestimate of the treatment effect. This was demonstrated by one trial reviewed for these guidelines that showed no difference between TENS and placebo TENS but demonstrated a significant benefit on pain relief of TENS compared with an untreated, unblinded control group.9 Few investigators (13/31 studies) reported adequate information regarding withdrawals and loss to follow-up or indicated whether they were considered in the data analysis. These weaknesses contribute to the lower-quality assessment scores in many of the systematic reviews conducted on rehabilitation interventions for knee pain.
The Philadelphia Panel agreed that clinical importance be defined as an improvement of 15% or more relative to a control (see article titled "Philadelphia Panel Evidence-Based Clinical Practice Guidelines on Selected Rehabilitation Interventions: Overview and Methodology" in this issue). Both clinical importance and statistical significance were required for grade A or B recommendations. With these requirements, inconclusive results were reached for several interventions (grade C).
Ottenbacher69 lists several difficulties for rehabilitation specialists: (1) discrimination between clinical and statistical significance, (2) low statistical power in detecting minimal clinically important differences (MCIDs), and (3) lack of replication of rehabilitation studies to strengthen evidence-based practice. Some studies (18/25 studies) did not use adequate sample sizes to detect important differences with confidence (Appendix 2). These issues have led to inconclusive results in other systematic reviews.14,54
The Philadelphia Panel EBCPGs for the management of knee pain are mainly in agreement with previous and recent EBCPGs21,23 and clinical practice guidelines70 for knee pain described in Tables 8 and 9, especially for therapeutic exercises. The Philadelphia Panel EBCPGs for knee pain have the advantage that they were developed based on a systematic grading of the evidence determined by an expert panel, and the evidence was derived from systematic reviews and meta-analyses using the Cochrane Collaboration methodology. The finalized EBCPGs were circulated for feedback from practitioners to verify their applicability and ease of use for practicing clinicians. This rigorous methodological procedure provides considerable credibility for rehabilitation specialists who intend to use these EBCPGs for knee management in their daily practice.
Therapeutic Exercises
The main aim of therapeutic exercises is to improve functional status by increasing muscle strength, improving flexibility, and increasing pulmonary function of the client, depending on the type of exercise (usually functionally specific). Our meta-analysis showed that traditional therapeutic exercises are beneficial for pain relief and patient global assessment in people with knee osteoarthritis (grade A for pain and patient global assessment). Improved function was shown in 3 RCTs, but did not reach statistical significance, and was assigned a grade C+ recommendation. These exercises included combinations of strengthening, stretching, and functional exercises.7174 In contrast, preoperative strengthening exercises showed no benefit on postsurgery knee function. There was no evidence regarding acute knee pain. The current results for knee conditions are in agreement with recent reviews for traditional therapeutical exercises.14,7478 Furthermore, the feedback survey showed that 98% of the respondents agreed with the guideline.
Therapeutic exercises may compensate for arthrogenic impairment in quadriceps femoris muscle sensorimotor function, diminished proprioceptive acuity, and decreased postural stability associated with reduced functional performance of patients with osteoarthritis.55 Strengthening exercises also improve gait and attenuate knee pain in activities of daily living among patients with osteoarthritis.79 Types of exercises, intensity, and progression need to be clarified according to patient-specific classification of physical dysfunction, needs, treatment goals, and outcomes.14,54,72,78,8084 The lack of a statistically significant effect on function warrants further research because therapeutic exercises are often prescribed to address functional limitations, muscle weakness, and instability. Insufficient evidence was found for use of therapeutic exercise for knee tendinitis and chondromalacia patellae.
Therapeutic Ultrasound
Therapeutic ultrasound did not demonstrate a clinically important benefit for osteoarthritis of the knee or for patellofemoral pain syndrome.5,24 No studies were found for postsurgery or acute conditions. Other research work is obviously needed for knee pain at different stages and for different conditions. The BMJ21 and ACR23 guidelines did not evaluate therapeutic ultrasound for knee pain.
One trial5 used continuous therapeutic ultrasound, which generates vasodilatation,85 combined with a 2-minute ice application, which induces vasoconstriction.86 Other confounding variables such as randomization method, characteristics of the device, size of the applicator, and study duration might have contributed to the lack of effect of therapeutic ultrasound for patellofemoral pain syndrome found by this trial.46,49 These results concur with those of previous reviews.46,78,87 Puett and Griffin78 also conclude that no support exists in the literature for therapeutic ultrasound treatment prior to therapeutic exercise in management of knee osteoarthritis.
TENS
Clinical benefit was demonstrated in our meta-analysis of TENS for knee osteoarthritis.9,28,30,31,35,88 In contrast, our meta-analysis of TENS after knee surgery showed no benefit (level I, grade C). Other reviews of TENS have not found evidence of benefit.78,89 One of these reviews78 did not use Cochrane Collaboration methodology and considered only 3 of the 6 studies included in our meta-analysis.28,31,35 The other review did not specifically study the effectiveness of TENS for knee osteoarthritis; the investigators included various conditions involving pain.89
Transcutaneous electrical nerve stimulation is thought to generate neuroregulatory peripheral and central effects9093 and modulate pain transmission.9496 The Philadelphia Panel EBCPGs (level I, grade A) cannot be compared with BMJ21 and ACR23 guidelines because these guidelines did not evaluate TENS for pain relief.
Therapeutic Massage
There were insufficient data for the Philadelphia Panel to make a recommendation regarding therapeutic massage (Cyriax's deep transverse frictions) as an intervention alone for knee tendinitis. There are no other systematic reviews on massage for knee pain. The Philadelphia Panel recommendation cannot be compared with the BMJ,21 ACR,23 or Manal and SnyderMackler70 guidelines because they did not evaluate massage as an intervention for knee pain.
There are a number of confounding variables related to the therapeutic application of massage. For example, the effectiveness of massage is influenced by the types of maneuvers used, the massage approach adopted, years of experience of the therapist, number and size of the muscles involved, patient position, pressure, rhythm and progression, and frequency and duration of the treatment sessions.97
Thermotherapy
The Philadelphia Panel concluded that there was poor evidence to include or exclude thermotherapy for postsurgery knee pain. This recommendation is based on only one RCT of cryotherapy (with cold gel packs) in which both groups received therapeutic stretching and isometric strengthening exercises.8 We also found poor evidence to include or exclude ice massage for knee osteoarthritis; however, this finding was based on a trial that used ice massage applied to acupoints.23 There was insufficient evidence to make a recommendation regarding thermotherapy for patellofemoral pain syndrome. These results are in agreement with a recent systematic review78 for osteoarthritis of the knee. The BMJ,21 ACR,23 and Manal and Snyder-Mackler70 guidelines did not evaluate thermotherapy for knee pain.
Physiological studies have shown significant effects of cryotherapy on circulatory and temperature responses, muscle spasm, and inflammation,86,87 but its mechanism of action has not yet been fully elucidated.86 It is unknown whether these physiological effects translate to important effects on clinical outcomes (such as pain and functional status).
EMG Biofeedback, Electrical Stimulation, and Combined Rehabilitation Interventions
Despite the positive physiological effect of these interventions,98 either there are no clinical data or there is insufficient clinical information on the effectiveness of EMG biofeedback, electrical stimulation, and combined rehabilitation interventions for acute and chronic knee pain.
The Philadelphia Panel was unable to make clinical recommendations regarding these specific interventions. Similarly, the BMJ21 and ACR23 guidelines did not evaluate these modalities.
Overall
The main difficulty in determining the effectiveness of rehabilitation interventions is the lack of well-designed prospective RCTs. An enormous research effort is needed to conduct RCTs for almost every rehabilitation intervention for knee pain. This situation is critical compared with the growing knee research area. There is a pressing need for further work on other rehabilitation interventions for knee pain, particularly considering the increased use of physical therapists in North America. Furthermore, these trials need to use standardized and validated outcomes, describe fully the intervention and its characteristics, and consider evaluating subgroups of particular interest.
| CONCLUSION |
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| Appendix 1. |
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| Appendix 2. |
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| Footnotes |
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Acknowledgments: Summer students: Sarah Milne, Michael Saginur, Marie-Josée Noël, Mélanie Brophy, Anne Mailhot
* Oxford, England: The Cochrane Collaboration, 2000. ![]()
| References |
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L. L Currier, P. J Froehlich, S. D Carow, R. K McAndrew, A. V Cliborne, R. E Boyles, L. T Mansfield, and R. S Wainner Development of a Clinical Prediction Rule to Identify Patients With Knee Pain and Clinical Evidence of Knee Osteoarthritis Who Demonstrate a Favorable Short-Term Response to Hip Mobilization Physical Therapy, September 1, 2007; 87(9): 1106 - 1119. [Abstract] [Full Text] [PDF] |
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R. A Wong, B. Schumann, R. Townsend, and C. A Phelps Author Response Physical Therapy, August 1, 2007; 87(8): 999 - 1001. [Full Text] [PDF] |
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R. A Wong, B. Schumann, R. Townsend, and C. A Phelps A Survey of Therapeutic Ultrasound Use by Physical Therapists Who Are Orthopaedic Certified Specialists Physical Therapy, August 1, 2007; 87(8): 986 - 994. [Abstract] [Full Text] [PDF] |
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M. Porcheret, K. Jordan, P. Croft, and in collaboration with the Primary Care Rheumatolog Treatment of knee pain in older adults in primary care: development of an evidence-based model of care Rheumatology, April 1, 2007; 46(4): 638 - 648. [Abstract] [Full Text] [PDF] |
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W Zhang and M Doherty EULAR recommendations for knee and hip osteoarthritis: a critique of the methodology Br. J. Sports Med., August 1, 2006; 40(8): 664 - 669. [Abstract] [Full Text] [PDF] |
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Ottawa Panel Members, Ottawa Methods Group, L. Brosseau, G. A Wells, P. Tugwell, M. Egan, C.-J. Dubouloz, L. Casimiro, V. A Robinson, L. Pelland, et al. Ottawa Panel Evidence-Based Clinical Practice Guidelines for Therapeutic Exercises and Manual Therapy in the Management of Osteoarthritis Physical Therapy, September 1, 2005; 85(9): 907 - 971. [Abstract] [Full Text] [PDF] |
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A. Delitto Research in Low Back Pain: Time to Stop Seeking the Elusive "Magic Bullet" Physical Therapy, March 1, 2005; 85(3): 206 - 208. [Full Text] |
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G. L. Cheing and C. W. Hui-Chan Would the addition of TENS to exercise training produce better physical performance outcomes in people with knee osteoarthritis than either intervention alone? Clinical Rehabilitation, May 1, 2004; 18(5): 487 - 497. [Abstract] [PDF] |
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