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 years of age (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 for osteoarthritis patients is to improve pain control and improve physical capacity. This might be achieved by the following changes: 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 levels, 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.
Over the years, aquatic exercise has 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 to 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 be advantageous for 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). Aquatic exercise 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 were eligible if they were randomised controlled trials or quasi-randomised clinical trials.
Types of participants
Patients with osteoarthritis (OA) in either one or both knee(s) or one or both hip(s), as defined by the American Rheumatology Association (ARA) criteria (Altman 1986) who did not suffer from any other arthritic conditions or any other disease which may affect the joints. All degrees of, and both primary and secondary OA, were eligible. Studies including a mixture of patients with hip or knee OA, were examined in order to evaluate whether it was possible to distinguish between knee and hip OA. Studies including a mixture of different rheumatic patients were included only if it was possible to extract the data from the OA patients. If possible, the level of disability was described, and possible gender difference were considered.
Types of interventions
Studies included one treatment group in which aquatic exercise was applied. All types of exercises developed in the therapeutic/heated indoor pool (ROM, dynamics, aerobics etc.) were permitted. The use of medication, alternative therapies or lifestyle changes were described, and must have been 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 was the benefit or harm of aquatic exercise therapy. Beneficial outcome measures recommended by OMERACT III (Bellamy 1997) included the following:
Primary outcomes
Pain
Functional status (for example, measured by the Activities of Daily Living Scale, patient global assessment)
Radiographs (studies > one year)(Bellamy 1997)
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.
Search methods for identification of studies
1) Bibliographic databases
We searched the following databases: CENTRAL (The Cochrane Library Issue 2, 2006), MEDLINE from 1949, EMBASE from 1980, CINAHL from 1982, Web of Science from 1945, all up to May 2006.
The search strategies contained the following elements:
Osteoarthritis/osteoarthrosis, and if possible osteoarthritis of the knee or of the hip, and all reasonable expressions for aquatic therapy. There was no restriction on language.
Specified search strategies
We used broad search strategies which created a high proportion of non-relevant references, but since a wide range of terms have been used for aquatic exercise over the years, this did, on the other hand, ensure that relevant references were retrieved. We searched for both osteoarthritis and the more specific 'knee' or 'hip' osteoarthritis. This is important to prevent missing out on important references using more specific terminology. Aquatic exercise is not clearly indexed in the bibliographic databases, but the aforementioned considerations ought to have lead to a fairly complete retrieval.
Search strategies:
Cochrane Central Register of Controlled Trials (CENTRAL):
This database was searched following the strategy for search in MEDLINE and EMBASE (see below).
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)
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
Web of science
I
osteoarthritis OR knee osteoarthritis OR hip osteoarthritis OR osteoarthros?s
AND
balneotherapy OR swimming 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 OR knee osteoarthritis OR hip osteoarthritis OR osteoarthros?s
AND
physiotherapy OR physical therapy OR sport *
AND
water OR aquatic OR pool
The end result is:
I OR II
PEDro (Physiotherapy Evidence Database):
Therapy: Hydrotherapy, Balneotherapy.
The Danish National Library of Science and Medicine's catalogue in the systematic group covering pool therapy was searched to make sure that there would not be any older studies published as monographs.
2) Reference checking
We checked the references of included studies for further relevant literature.
3) Handsearching
We handsearched abstracts published in Physical Therapy from the APTA Annual Conference 2002 to 2006, in Rheumatology Supplement from BSR Annual Meeting 2002 to 2006, and from the Scandinavian Journal of Rheumatology from the Scandinavian Congress of Rheumatology 2002 to 2006.
4) Other
In addition, we contacted institutions, societies, specialists known to have expertise in aquatic therapy and authors of included studies to identify any additional published or unpublished data.
Data collection and analysis
Selection of trials
Two review authors (EMB, HL) independently screened abstracts, keywords and publication type of all publications obtained from the described searches. Uncertainty or disagreements were resolved by discussion with BDS, HD and KBH. Where the method of randomization or data (standard deviation or error) was not clearly described, or where data were missing, the authors of the study in question were contacted to clarify the issues. All studies which might be eligible RCT's, or quasi-RCT's, were obtained in full and assessed, based on the inclusion and exclusion criteria. Trials which were excluded were identified and are presented with reasons for exclusion.
Quality assessment of included studies
In order to ensure that variation was not caused by systematic errors in the study design or execution, two review authors (EMB, HL) independently assigned each selected study to quality categories described in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2005). Uncertainty or disagreements were resolved by discussion with BDS, HD and KBH. Where further information about the studies was needed, the authors of these studies were contacted for clarification. The following five criteria were used:
a) Blinding of provider or patient
MET: The patient or the provider was blinded for the intervention.
UNCLEAR: Blinding not reported
NOT MET: The patient and the provider were not blinded for the intervention.
(a) is an impossible criteria to set for aquatic exercise since both patient and provider clearly is aware of the treatment).
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 were allocated to the following groups: a) low risk of bias (all criteria MET), b) moderate risk of bias (three to four criteria MET), and c) high risk of bias (less than three criteria MET). The studies' possible conflict of interest was considered as part of the quality assessment procedure. Other methodological issues such as baseline comparability, sample size etc. is documented in the table 'Characteristics of included studies'.
Analyses and Presentation
The studies were 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. range of motion (ROM) exercise, aerobic exercise, group exercise, individual exercise).
- Primary outcomes, as pain and physical function.
The results were allocated into comparable groups. The three patient groups considered were 1) a mixed group suffering from hip and/or knee osteoarthritis, 2) a group suffering from hip osteoarthritis alone, and finally 3) a group suffering from knee osteoarthritis alone.
In each group, the analysis was divided into aquatic exercise versus control, or aquatic exercise versus another type of exercise.
The meta-analysis focused on outcomes concerning improvement in the following categories:
- pain
- function
- walking ability
- stiffness
- quality of Life
- mental health
Data extraction
Two review authors (EMB, HL) independently extracted the results for statistical analysis. Uncertainty or disagreement were resolved by discussion with RC, HD, KBH, and BDS.
When choosing the outcome measure for analysis, it is always the primary outcome decided by the authors. Otherwise we decided on the following priority list, if more than one measured parameter for a category was present in the study.
The list for pain measures (in descending order): WOMAC-Pain (Western Ontario and McMaster Universities Osteoarthritis Index), VAS-Pain (Visual Analogue Scale), HAQ-Pain (Health Assessment Questionnaire), SF-36-Pain (Short Form), SF-12-Pain, AIMS-Pain (Arthritis Impact Measurement Scale).
The list for function measures (in descending order): WOMAC-Function, HAQ-Function, DRI (Disability Rating Index), SF-36-Function, ASEQ-Function (Arthritis Self-Efficacy Questionnaire), FAP-Score (Functional Ambulation Performance), SPF-Scale (Summary Physical Function), AAP (Adelaide Activities' Profile).
The list for walking ability (in descending order): 6MW (Six Minutes Walk), 8 feet walk time, one mile walk time.
The list for stiffness measures (in descending order): WOMAC-Stiffness, Range of Motion (ROM).
The list for quality of life measures (in descending order): SF-12-Quality of Life, AIMS-2-Affect, PQOL (Perceived Quality Of Life Scale), QWB (Quality of Well-Being Scale), GSI (Global Self-Rating Index), EQ-VAS (European Quality of Life Visual Analogue Scale).
The list for mental health measures (in descending order): SF-36-Mental, SF-12-Mental, AIMS-2-Satisfaction, ASEQ-Mental, Satisfaction (Satisfaction with Aquatic Therapy Scale), QWB, Psychological Distress.
Comparisons
Comparisons were made according to type of control group (no treatment, other treatment). Pooling of trials was only attempted if at least two trials of comparable aquatic-therapy protocols with the same conditions, and comparable outcome measurements, existed.
Statistical analysis was performed using RevMan 4.2 software.
Continuous Outcomes
Since similar, but not identical, instruments were used to measure pain or functional status etc., we calculated standardized mean differences (SMD). Heterogeneity was tested by applying a chi-squared test. If the P-value of this test was lower than 0.25, an I
Grading of evidence
The grading system used (Tugwell 2004) is recommended by the Cochrane Musculoskeletal Review 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: Randomised trials 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 was provided for comparison of one of the agents to placebo, and 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 are compiled under additional tables to improve the readability of the review. Continuous outcome tables are also presented under 'Additional tables'. Absolute benefit was calculated as the improvement in the intervention group minus the improvement in the control group, in original units. Relative difference in change from baseline was calculated as the absolute benefit divided by the baseline mean of the control group.
Results
Description of studies
See: Characteristics of included studies; Characteristics of excluded studies.
Results of the search
The literature search identified 30 potential studies.
Included studies
Out of these, six RCTs were included in the systematic review (Cochrane 2005; n=310), (Foley 2003; n=70), (Patrick 2001; n=246), (Wyatt 2001; n=46), (Stener-Victorin 2004; n=28), (Wang 2004; n=43). Of the included studies, four studies recruited patients with both knee or hip osteoarthritis or both (Cochrane 2005; Foley 2003; Patrick 2001; Wang 2004); one study recruited patients with hip OA alone (Stener-Victorin 2004), and one study recruited only patients with knee OA (Wyatt 2001).
Excluded studies
Twenty-four studies were excluded (see table 'Characteristics of excluded studies' for further information).
Risk of bias in included studies
Hip and knee osteoarthritis mixed
Two of the studies had a sample size higher than 50 in each group (Cochrane 2005; Patrick 2001). One study recruited 35 in each group (Foley 2003) and one study recruited 22 in each group (Wang 2004). Two of the studies performed a blind assessment of the outcome (Cochrane 2005; Foley 2003), while it was unclear in the two other studies (Patrick 2001; Wang 2004). Three studies fulfilled the demand of less than 20% withdrawal (Foley 2003; Patrick 2001; Wang 2004), but in one other study withdrawal was not exceeding 28% (Cochrane 2005). Finally, three of the studies fulfilled the demand of concealment of allocation (Cochrane 2005; Foley 2003; Wang 2004), while one study did not (Patrick 2001). In conclusion, the evidence presented in this review is based upon a GOLD level of evidence.
Hip alone
Only one study was included (Stener-Victorin 2004). The evidence for hip alone was graded as SILVER, since concealment of allocation was unclear, attempt to avoid co-intervention was not mentioned, losses to follow up was greater than 20%, and the assessor was not blinded.
Knee alone
Only one study was included (Wyatt 2001). The evidence for knee alone was graded as SILVER, since concealment of allocation was unclear, attempt to avoid co-intervention was not mentioned, losses to follow up were not reported, and no intention-to-treat analysis was presented
Effects of interventions
Aquatic exercise versus control - measured immediately after the exercise period
Hip and knee mixed
There was a small but statistically significant effect on function (SMD: 0.26, 95% confidence interval (CI) 0.11 to 0.42), quality of life (SMD: 0.32, 95% CI 0.03 to 0.61), and mental health (SMD: 0.16 95% CI 0.01 to 0.32) in favour of aquatic exercises. A minor effect of a 3% absolute reduction (0.6 fewer points on a 0 to 20 scale) and 6.6% relative reduction was found for pain (SMD: 0.19, 95% CI 0.04 to 0.35). No statistically significant differences were found for walking ability or stiffness (Cochrane 2005; Foley 2003; Patrick 2001; Wang 2004).
Hip alone
No evidence of effect on function or quality of life was found in this study (Stener-Victorin 2004).
Knee alone
No study met the inclusion criteria for patients with only knee OA, and comparing aquatic exercise with a non-exercising control group.
Aquatic exercise versus control - follow-up measurements
Hip and knee mixed
Only one study reported a six month follow-up (Cochrane 2005). No difference was found six months after completion of treatment on pain, function, stiffness or mental health (Cochrane 2005).
Hip alone
No statistically significant difference in function or quality of life was found in this study (Stener-Victorin 2004).
Knee alone
No study met the inclusion criteria for patients with only knee OA, and comparing aquatic exercise with a non-exercising control group.
Aquatic exercise versus exercise on land - measured immediately after the exercise period
Hip and knee mixed
No study met the inclusion criteria for patients with hip and knee OA, and comparing aquatic exercise with a land-based exercise group.
Hip alone
No study met the inclusion criteria for patients with only hip OA, and comparing aquatic exercise with a land-based exercise group.
Knee alone
A large effect was found for pain (SMD: 0.86, 95% CI 0.25 to 1.47) in favour of aquatic exercises, while no evidence of effect was seen on stiffness or walking ability (Wyatt 2001).
Aquatic exercise versus exercise on land - follow-up measurements
Hip and knee mixed
No study met the inclusion criteria for patients with hip and knee OA, and comparing aquatic exercise with a land-based exercise group.
Hip alone
No study met the inclusion criteria for patients with only hip OA, and comparing aquatic exercise with a land-based exercise group.
Knee alone
No study met the inclusion criteria for patients with only knee OA, and comparing aquatic exercise with a land-based exercise group at follow-up.
Clinical relevance tables are available for knee and hip mixed ( Table 1), hip alone ( Table 2), and knee alone ( Table 3).
Adverse effects
Two studies reported that neither aquatic nor land-based exercise increase self-reported pain or other symptoms (Foley 2003; Wang 2004). Foley also reported that no difference in drug consumption was observed between the groups (Foley 2003). One study concluded that none of the drop outs was due to the exercise interventions (Cochrane 2005). The remaining three studies did not report anything about adverse effects (Wyatt 2001; Patrick 2001; Stener-Victorin 2004).
Radiographic evaluation
No radiographic evaluation was performed in any of the included studies. However, since all studies lasted shorter than one year, this outcome was not relevant (Bellamy 1997).
Discussion
This review is concerned about the use of aquatic therapy in the treatment of osteoarthritis of the lower extremities. The condition is common and affects in particular, older people. There is no cure, and it is therefore important to look into both prevention and treatment. The economical consequences of this disease when it develops into disability are serious (Rothfuss 1997). A treatment of osteoarthritis which can stop or slow down the disabling process is therefore of great importance, both when looking at the economy, and when looking at the quality of life for the patient.
The lower extremities include two joints, the hip and knee. These joints are very different both in type and loading. The treatment having an effect on the knee may therefore not have any effect on the hip joint. In an ideal world, studies would have been designed to look at aquatic therapy on only one of these joints. In the real world, it seems that it has been difficult to define patient groups which were only suffering from osteoarthritis of one of the joints. Furthermore, the described exercises in the included studies are not specific to the knee of hip, but both joints. We have therefore generally carried out analyses on mixed joint studies.
To carry out a meta-analysis, a grading of retrieved studies into the categories of platinum, gold, silver and bronze is problematic when looking at aquatic or other exercise therapy. It is obvious that patient and provider cannot be blinded to the treatment. The criteria of blinding must in this case be considered irrelevant, and the overall analysis for the mixed group of patients with hip and knee OA is acceptable as gold standard. The awareness of being treated may, on the other hand, still provide a bias when compared to a control group not exposed to treatment. In the cases where aquatic exercise is compared to exercises on land, one must assume that there is no such effect, since both groups receive treatment and attention from providing staff. For all other studies, bias cannot be ignored completely.
We found very few studies of a quality acceptable for a meta-analysis. As our end result, only four studies fulfilled all the set criteria in the group with a mixture hip and knee OA, and only one study was acceptable for analysis in each of the groups knee OA alone and hip OA alone. A separation on joint or exercises aimed specifically on one of the two joints in question was not possible in any of the mixed group studies. In this group, two studies had less than 20% drop-out while the other two studies in this group had less than 28% drop-out. This is very good for a therapy which demands out of house treatment several times a week, although the ideal drop-out ought to be less than 20%.
At the end of the treatment, improvement was seen in physical function, pain, mental health and quality of life, when compared to a control group. These effects did not last up to a six month follow-up in the only study reporting on this (Cochrane 2005), It may be asked if aquatic exercise has to be maintained at some level to preserve the improvements seen at the end of the treatment or if other therapies, like exercise on land, should be applied following the aquatic exercise. If the patients' physical ability has improved, exercises on land become more feasible, especially in the more disabled patients. Furthermore, exercise on land may more easily be arranged and at a lower cost.
Exercise may not in all cases be beneficial for patients with knee or hip OA. One earlier study indicates that strengthening exercise may increase the OA progression if the patient has a varus malalignment higher than five degrees (Sharma 2003), and another study of land-based exercise for patients with knee OA indicates an increase in knee oedema following exercise (Rogind 1998). Report of adverse events of a treatment is important for any treatment. In the present review, only two studies reported that the interventions did not increase self-reported pain or symptom scores (Foley 2003; Wang 2004). No comments on adverse effects were present in the other included studies. In future studies of effects of aquatic exercise it is therefore vital to report on adverse as well as on beneficial effects of the treatment, and it is recommended that the reporting of adverse effects is presented in accordance to the Ioannidis and Lau classification (Ioannidis 2001; Ethgen 2005).
Since only one study (Stener-Victorin 2004) compared aquatic exercise to control in hip OA patients, this is still an area in need of further study. From this one trial, no positive or negative effects of aquatic exercise were seen just after or at the three month follow-up. Based on this study, we can only conclude that aquatic exercise as applied here has no effect on hip OA alone. An analysis of the exercises in the programme which had no effect, and a consideration of what type of training may improve a hip joint without creating damage, would be the basis on which further studies ought to be designed, before discarding aquatic exercise as a possible treatment of hip osteoarthritis.
One study comparing land exercise with aquatic exercise which concerned only knee OA qualified for inclusion and this study was of poor quality (Wyatt 2001). A large positive effect on pain at the end of treatment was found, and no adverse effects were seen. Unfortunately, no follow-up was carried out. An effect on pain though is a very important finding, since it suggests that at least part of the treatment involving training and strengthening of the muscles around the knee should take part as aquatic exercise, until the patient's condition has improved. Pain is often the limiting factor when using exercise as part of a treatment programme.
The lack of a long-term effect of aquatic exercise found when analysing the group of mixed hip and knee osteoarthritis patients may be due to the lack of effect on the hip osteoarthritis which could hide an effect on the knee osteoarthritis. Since there is no way of separating the two types of patients in the existing studies, one can only recommend future studies to be joint specific and to design an exercise programme which is aimed at the specific joint.
Authors' conclusions
Implications for practice Aquatic exercise has some short-term beneficial effects on the condition of OA patients with hip or knee OA or both. The controlled and randomised studies in this area are still too few to give further recommendations on how to use this therapy. There is a positive effect on both mixed knee and hip OA and on knee OA alone at the end of an aquatic training programme. This is not seen in the only study applying this treatment on hip OA alone. No long-term effects have been found. Aquatic exercise may therefore be considered as the first part of an exercise therapy programme to get particularly disabled patients introduced to training. Further physical therapy interventions may then continue on land, but the balance between the two types is still not clear based on the available studies. Based upon clinical experience, experts consider it to be a useful intervention thus more research is needed to see if the indications of a positive effect of aquatic exercise can be supported by appropriately designed studies with medium and long-term term follow up. |
Implications for research There are very few randomised controlled trials which consider the effects of aquatic exercise on knee or hip osteoarthritis. Furthermore, neither type of exercise nor dose (intensity, frequency and duration) are clearly described in these studies. The physiological knowledge of osteoarthritis is still limited. Analyses of earlier studies concerning biomechanics and neuromuscular function of the lower extremities may assist in deciding the correct treatment, and new research concerning the function of the lower extremities and the effect of different physical interventions is much needed. Based on these aforementioned studies, a documented hypothesis for the treatment can be expressed, and a randomised controlled trial based on the hypothesis could be designed. Future studies of this type are needed if the optimal use of aquatic exercise in the treatment of knee and hip osteoarthritis is to be determined. |
Acknowledgements
We thank the staff at Interlibrary Loan Department, Copenhagen University Library North, for finding even the most obscure references.
Data and analyses
- Top of page
- Background
- Objectives
- Methods
- Results
- Discussion
- Authors' conclusions
- Acknowledgements
- Data and analyses
- What's new
- History
- Contributions of authors
- Declarations of interest
- Sources of support
- Index terms
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What's new
Last assessed as up-to-date: 14 August 2007.
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History
Protocol first published: Issue 4, 2005
Review first published: Issue 4, 2007
Contributions of authors
Content:
Bartels EM, Lund H, Hagen KB, Dagfinrud H, Danneskiold-Samsøe B
Methodology:
KB Hagen, EM Bartels, H Lund, H Dagfinrud, Christensen R,
Statistics:
R Christensen, KB Hagen
Declarations of interest
None known
Sources of support
Internal sources
- OAK foundation, Denmark.
- Copenhagen University Library, Denmark.
External sources
- No sources of support supplied
Index terms
Medical Subject Headings (MeSH)
*Water; Balneology; Chronic Disease; Exercise; Exercise Therapy [*methods]; Hydrotherapy [methods]; Osteoarthritis, Hip [*therapy]; Osteoarthritis, Knee [*therapy]; Randomized Controlled Trials as Topic; Swimming
MeSH check words
Humans