Aquatic exercise for the treatment of knee and hip osteoarthritis
Abstract
This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:
To compare the effectiveness and safety of aquatic exercise interventions in the treatment of knee and hip osteoarthritis when these are compared to other interventions or no intervention.
Background
Osteoarthritis (OA) is a chronic disease 'characterized by joint pain, tenderness, limitation of movement, crepitus, occasional effusion, and variable degrees of local inflammation, but without systemic effects' (Brandt 1986). 'The disease process not only affects the articular cartilage, but involves the entire joint, including the subchondral bone, ligaments, capsule, synovial membrane, and periarticular muscles' (Flores 2003). OA occurs most frequently in knees hands, hips, back and neck (Felson 2003). The characteristics of the disease are thickening of the joint capsule, progressive cartilage loss, and osteophyte formation, leading to functional impairments (Oliveria 1995; Sowers 2000). Epidemiological studies show that osteoarthritis accounts for more trouble in walking and climbing stairs than any other musculoskeletal disease (Guccione 1994). At present, only treatment of the symptoms and treatment to prevent further development of the disease are possible. Knee and hip osteoarthritis are widespread diseases, seen in up to 6% of the population (Felson 1998). OA is hardly ever seen in children or adults younger than 40 (Oliveria 1995; Sowers 2000). However, the prevalence increases with age, and, due to the growing group of elderly people, a higher prevalence will probably be seen in the future. This review is limited to osteoarthritis of the knee and hip joint.
The aim of physical therapy treatment of osteoarthritis patients is to improve pain control and improve physical capacity. This could be achieved by increased muscle strength, improved balance and coordination of movements, and better joint mobility (Hurley 2003). Improved muscle strength in osteoarthritis patients is correlated to the patient's functional level (Gur 2002). However, due to pain or very low functional level, it is often difficult to apply an adequate strength‐exercise program. In addition, with increasing joint damage, it may not be possible to carry out a whole range of exercises, normally possible on land, with an osteoarthritis patient.
Aquatic exercise has over the years been known as pool therapy, hydrotherapy, and sometimes in earlier literature even balneotherapy. The treatment has to take part in water and involve exercises. The water is most often heated to 32º‐36º Celsius. Today, balneotherapy covers use of hot‐water treatment known to ease pain, decrease stiffness and cause muscle relaxation, and this has been further developed with various forms of salt and/or sulphur treatment, mud packs, and jet streams (spa‐therapy)(Verhagen 2000). Since the main aim of physical therapy for osteoarthritis patients is to improve their physical ability, the present review will only look at studies where aquatic exercise in some form has been applied.
Aquatic exercise may have advantages to osteoarthritis patients. When the hot‐water element is included, it is thought that it gives the arthritis patients decreased pain sensation, decreases stiffness of the muscular‐skeletal system, and causes muscle relaxation (Elkayam 1991). Warm water treatment may therefore be a better base on which to start training of osteoarthritis patients than a similar training on land.
Objectives
To compare the effectiveness and safety of aquatic exercise interventions in the treatment of knee and hip osteoarthritis when these are compared to other interventions or no intervention.
Methods
Criteria for considering studies for this review
Types of studies
Studies will be eligible if they are randomized controlled trials or quasi‐randomized clinical trials.
Types of participants
Patients with osteoarthritis (OA) in either one or both knee(s) or one or both hips, as defined by the American Rheumatology Association (ARA) criteria (Altman 1986) who do not suffer from any other arthritic conditions or any other diseases, which may affect the joints. All degrees of, and both primary and secondary OA, will be eligible. Studies including a mixture of different rheumatic patients will only be included if it is possible to extract the data from the OA patients. If possible, the level of disability will be described, and possible gender difference will be considered.
Types of interventions
Studies will include one treatment group in which aquatic exercise is applied. All types of exercises developed in the therapeutic / heated indoor pool (ROM, dynamics, aerobics etc.) will be permitted. The use of medication, alternative therapies or lifestyle changes will be described, and must be comparable in the groups studied. When comparing different programs, types of exercise, depth of water, and temperature will be considered.
Types of outcome measures
The primary outcome for measurement of effectiveness will be the benefit or harm of aquatic exercise therapy. Beneficial outcome measures recommended by OMERACT III (Bellamy 1997) will include the following:
Primary outcomes:
Pain
Functional status (for example, measured by the Activities of Daily Living Scale, Patient Global assessment)
Radiographs (studies > 1 year))
Adverse effects
Total number withdrawals
Number withdrawals due to adverse events
Total adverse events
Secondary outcomes: Consumption of medicine, home care consumption, surgery, return to work, psychological well being, coping skills, measures such as ambulatory function, walking speed, endurance in the form of a standardized walk test (e.g. 6 minute walk), use of gait aids, etc.
Search methods for identification of studies
1) Search in bibliographic databases:
Following databases will be chosen: MEDLINE from 1949, EMBASE from 1980, CINAHL from 1982, Web of Science from 1945, all up to August 2005.
The search strategies will contain following elements:
Osteoarthritis/osteoarthrosis, and where possible osteoarthritis of the knee or of the hip, all both as keywords with all subheadings, and as free text. Pool therapy, swimming, aquatic exercises, and aquatic therapy, water running, wet west, aquatics, pool exercise, aquatic therapy, water gymnastics, water exercise, training in water, aqua aerobics, hydrotherapy, swimming where possible as keywords with all subheadings, and otherwise as text word.
There will not be a restriction on language. Due to the number of references expected from these searches, a limit to outcome or effects of treatment will be applied in this review.
Specified search strategies
The searches are very broad and may therefore result in irrelevant results. On the other hand, carrying out a narrower search will not retrieve all relevant studies.
The reason for including both osteoarthritis and the more specific knee or hip osteoarthritis is that one loses some relevant references if only the more specific term is used.
Aquatic exercise is very badly defined, but the following searches should cover them all.
EMBASE
I
Osteoarthritis (Keyword exploded) OR Knee Osteoarthritis (Keyword exploded) OR hip osteoarthritis OR osteoarthros?s
AND
Balneotherapy (Keyword exploded) OR Swimming (Keyword exploded) OR hydrotherapy OR aquatic exercise* OR Aquatic sport* OR pool therapy OR water aerobics OR water exercise* OR water run* OR water training OR water gymnastics
II
Osteoarthritis (Keyword exploded) OR Knee Osteoarthritis (Keyword exploded) OR hip osteoarthritis OR osteoarthros?s
AND
Physiotherapy (Keyword exploded) OR sport (Keyword exploded)
AND
Water OR aquatic OR pool
The end result is:
I OR II
CINAHL
I
Osteoarthritis (Keyword exploded) OR osteoarthros?s
AND
Balneotherapy (Keyword exploded) OR Swimming (Keyword exploded) OR hydrotherapy (Keyword exploded) OR aquatic exercises (Keyword exploded) OR Aquatic sports (Keyword exploded) OR pool therapy OR water aerobics OR water run* OR water training OR water gymnastics
II
Osteoarthritis (Keyword exploded) OR osteoarthros?s
AND
Physical therapy (Keyword exploded)
AND
Water OR aquatic OR pool
The end result is:
I OR II
MEDLINE via PubMed
(Osteoarthritis OR Knee Osteoarthritis OR hip osteoarthritis OR Osteoarthros?s) AND (Balneotherapy OR Hydrotherapy OR Swimming OR Pool Therapy OR Aquatic Exercises OR Water Exercises OR Water)
Web of science
Same as the search in MEDLINE and EMBASE.
2) Other databases to be searched:
The Danish National Library of Science and Medicine's catalogue in the systematic group covering pool therapy to make sure that there would not be any older studies published as monographs.
Cochrane Central Register of Controlled Trials (CENTRAL):
As the search in MEDLINE and EMBASE.
PEDro (Physiotherapy Evidence Database):
Therapy: Hydrotherapy, Balneotherapy.
Lilacs (1982‐August 2005)
Osteoarthritis combined with one of the following:
1) Hydrotherapy
2) Balneotherapy
3) Aquatic exercises
4) Water exercises
5) Pool therapy
3) Reference checking
Following the selection of references from the found references, the reference lists will be checked for further relevant literature.
4) Search of abstracts published in special issues of specialized journals (e.g. Journal of Aquatic Physical Therapy, Aqualines ‐ Hydrotherapy Association of Chartered Society of Physiotherapy) or in Conference Proceedings (e.g. Annual Conference & Exposition of the American Physical Therapy Association (APTA), APTA Combined Sections Meeting).
5) Institutions, societies and specialists known to have expertise in aquatic therapy will be contacted for further information.
For 1)‐5): All references in the identified trials will be checked, and authors, where possible, will be contacted to identify any additional published or unpublished data.
Data collection and analysis
Selection of Trials:
Two reviewers (EMB, HL) will independently screen the abstracts of all publications obtained from searches following the search strategy. Uncertainty or disagreement will be resolved by discussion with BDS, HD and KBH. When further information is needed, the authors of studies will bee contacted for clarification. For articles that could be eligible RCT's, or quasi‐RCT's, the full article will be obtained and assessed, based on inclusion and exclusion criteria. Trials excluded will be identified and presented with reasons for exclusion.
Quality Assessment of Included Studies:
In order to ensure that variation is not caused by systematic errors in the study design or execution, two reviewers (EMB, HL) will independently assigned each selected study to quality categories described in the Cochrane Collaboration Handbook (Higgins 2005). Uncertainty or disagreement will be resolved by discussion with BDS, HD and KBH. When further information is needed, the authors of studies will be contacted for clarification. The following five criteria will be used:
a) Blinding of provider or patient:
MET: The patient or the provider was blinded for the intervention. We will note if one or both.
UNCLEAR: Blinding not reported
NOT MET: The patient and the provider were not blinded for the intervention.
b) Concealment of allocation
ADEQUATE: (A) indicates adequate concealment of the allocation (for example, by telephone randomisation, or use of consecutively numbered, sealed, opaque envelopes);
UNCLEAR: (B) indicates uncertainty about whether the allocation was adequately concealed (for example, where the method of concealment is not known);
INADEQUATE: (C) indicates that the allocation was definitely not adequately concealed (for example, open random number lists or quasi‐randomisation such as alternate days, odd/even date of birth, or hospital number).
c) Outcome assessment
MET: assessor unaware of the assigned treatment when collecting outcome measures;
UNCLEAR: blinding of assessor not reported and cannot be verified by contacting investigators ;
NOT MET: assessor aware of the assigned treatment when collecting outcome measures.
d) Co‐intervention
MET: interventions other than exercise avoided, controlled or used similarly across comparison groups;
UNCLEAR: use of interventions other than exercise not reported and cannot be verified by contacting the investigators;
NOT MET: dissimilar use of interventions other than exercise across comparison groups, i. e. differences in the care provided to the participants in the comparison groups other than the intervention under investigation.
e) Losses to follow‐up
MET: losses to follow up less than 20% and equally distributed between comparison groups;
UNCLEAR: losses to follow up not reported;
NOT MET: losses to follow up greater than 20%.
f) Intention‐to‐treat
MET: intention to treat analysis performed or possible with data provided;
UNCLEAR: intention to treat not reported, and cannot be verified by contacting the investigators;
NOT MET: intention to treat analyses not done and not possible for reviewers to calculate independently.
Studies will be grouped as those with a low risk of bias (all criteria MET), those with a moderate risk of bias (3‐4 criteria MET), and those with a high risk of bias (less than 3 criteria MET). The studies' possible conflict of interest will be considered as part of the quality assessment procedure. Other methodological issues such as baseline comparability, sample size etc. will documented in "Table of Included Studies."
Analyses and Presentation:
The studies will be stratified in sub‐categories according to:
‐ Length of follow‐up (e.g. at the end of treatment and three, six and twelve months after treatment).
‐ Type of intervention (e.g. ROM exercise, aerobic exercise, group exercise, individual exercise).
‐ Primary outcome as pain and physical function.
Comparisons:
Comparisons will be made separately according to type of control group (no treatment, other treatment). Pooling of trials will only be attempted if at least two trials of comparable aquatic‐therapy protocols with the same conditions, and comparable outcome measurements are available.
Statistical analysis will be performed using RevMan 4.2 software.
Continuous Outcomes:
For similar comparisons and outcome measures, we will calculate weighted mean differences (WMD) and 95% confidence intervals using a fixed effects model. When similar but not identical instruments are used to measure pain or functional status etc., standardized mean differences (SMD) will be calculated. Heterogeneity will be tested by applying a Chi‐square test. If the p‐value of this test is lower than 0.25, an I‐squared test will be performed. If the I‐squared test shows a value greater than 50%, we consider this to indicate a substantial heterogeneity, and a random effects model will be used.
Dichotomous Outcomes:
Relative risk (RR) and 95% confidence intervals using a fixed effects model will be applied for interpretation of the dichotomous outcome measures in this review. A random effects model will be considered if there is heterogeneity among the primary trials (see above). In the event of significant or clinical heterogeneity, trial results will not be pooled.
Grading of evidence
We will use the grading system described in the 2004 book Evidence‐based Rheumatology (Tugwell 2004) and recommended by the Musculoskeletal Group:
Platinum: A published systematic review that has at least two individual controlled trials each satisfying the following :
·Sample sizes of at least 50 per group ‐ if these do not find a statistically significant difference, they are adequately powered for a 20% relative difference in the relevant outcome.
·Blinding of patients and assessors for outcomes.
·Handling of withdrawals >80% follow up (imputations based on methods such as Last Observation Carried Forward (LOCF) are acceptable).
·Concealment of treatment allocation.
Gold: At least one randomised clinical trial meeting all of the following criteria for the major outcome(s) as reported:
·Sample sizes of at least 50 per group ‐ if these do not find a statistically significant difference, they are adequately powered for a 20% relative difference in the relevant outcome.
·Blinding of patients and assessors for outcomes.
·Handling of withdrawals > 80% follow up (imputations based on methods such as LOCF are acceptable).
·Concealment of treatment allocation.
Silver: A systematic review or randomised trial that does not meet the above criteria. Silver ranking would also include evidence from at least one study of non‐randomised cohorts that did and did not receive the therapy, or evidence from at least one high quality case‐control study. A randomised trial with a 'head‐to‐head' comparison of agents would be considered silver level ranking unless a reference were provided to a comparison of one of the agents to placebo showing at least a 20% relative difference.
Bronze: The bronze ranking is given to evidence if at least one high quality case series without controls (including simple before/after studies in which patients act as their own control) or if the conclusion is derived from expert opinion based on clinical experience without reference to any of the foregoing (for example, argument from physiology, bench research or first principles).
Clinical relevance tables
Clinical relevance tables will be compiled under additional tables to improve the readability of the review. For dichotomous outcomes, the number needed to treat will be calculated from the control group event rate and the relative risk using the Visual Rx NNT calculator (Cates 2003). Continuous outcome tables will also be presented under additional tables. Absolute benefit will be calculated as the improvement in the intervention group minus the improvement in the control group, in the original units. Relative difference in the change from baseline will be calculated as the absolute benefit divided by the baseline mean of the control group.
