Article Text
PDF
Abstract
Background Greater trochanteric pain syndrome (GTPS) can have a significant effect on quality of life.
Aim To evaluate the conservative treatments for GTPS.
Design This systematic review assessed risk of bias using the Cochrane Risk of Bias Tool and Cochrane Risk of Bias Tool for non-randomised studies of interventions.
Data sources On 13 January 2016, a comprehensive search was conducted, with no limit on year of publication for relevant studies in the MEDLINE, CINAHL, AMED and EMBASE databases.
Eligibility criteria for selecting studies English language randomised controlled trials, case–control or cohort studies reporting outcome data for conservative treatments for adults having a diagnosis of GTPS, or trochanteric bursitis, were included.
Results 8 studies (n=696) were eligible for inclusion in the review; corticosteroid injections (CSI) (n=6), shockwave therapy (n=2), home training (n=1) and orthotics (n=1). Based on pain, CSI demonstrated superior outcomes for up to 3 months compared with home training, radial shockwave therapy (RSWT) and usual care, in 4 studies demonstrating either a low or moderate risk of bias. Fluoroscopy-guided injections failed to show additional benefit. RSWT and home training had limited evidence. No conclusions can be drawn regarding the use of orthotics due to the serious risk of bias and methodological flaws within that study.
Conclusions This review demonstrates a paucity of high-quality research for the conservative treatments of GTPS. The risk of bias was low in only one study, demonstrating no additional benefit with fluoroscopically guided injections. Risk of bias in all remaining studies was varied. Standardisation of diagnostic criteria and outcome measures is essential to enable more powerful analysis.
- Hip
- Tendinopathy
- Exercise
- Corticosteroids
- Shockwave
Statistics from Altmetric.com
Introduction
Greater trochanteric pain syndrome (GTPS) is characterised by pain over the greater trochanter, which can refer down the lateral aspect of the hip.1 GTPS has an incidence of between 1.82 and 5.63 per 1000/year and is more prevalent in women than men,4–8 with some studies reporting the ratio to be as high as 4:1.9 The understanding surrounding the pathophysiology of GTPS has progressed over recent years. Historically, pain was understood to arise from inflammation of the trochanteric bursa (TB).10 This term has been disputed with trochanteric bursitis now being referred to as GTPS, which encompasses numerous causes, including gluteal tendonopathy. One study reported no aetiological role of bursal inflammation in GTPS,11 while another study found no histopathological evidence of ongoing acute bursitis or tendinitis.12 A further study concluded that bursal distension was uncommon and that it did not occur in the absence of gluteus medius tendon pathology.13 Histopathological findings have also demonstrated coexisting gluteal tendinopathy with associated bursal degeneration,12 with tendinosis being the most commonly found tendinopathy.14 ,15 Although gluteus medius tendon pathology is considered important in defining GTPS, peritrochanteric oedema and tendinosis are present in many patients without GTPS, or indeed without symptoms.14 ,16 In other tendinopathies, a poor correlation has been found between symptom improvement and changes in tendon structure seen on ultrasound imaging.17 Where the pain of tendinopathy arises, however, is a recent focus for research, with one review finding evidence for tendon-based nociceptive contributions and extensive mechanisms within the periphery and the central nervous system.18
GTPS is a clinical diagnosis; however, in refractory cases, further imaging can be indicated. Clinical diagnosis is commonly made based on the site of pain (lateral hip pain) and tenderness on palpation of the greater trochanter;19–21 however, other criteria have been observed, such as pain on side lying.20 ,22 This variation in diagnostic criteria increases the risk of diagnostic error and may result in erroneous conclusions being drawn regarding treatment effectiveness. Historically, conservative treatments such as rest/activity modification,3 ,23 ,24 anti-inflammatory medication,3 ,23 ,24 physiotherapy3 and local corticosteroid injections (CSI)3 ,23 ,24 are employed as first-line management, with some refractory cases requiring surgical intervention.3 ,23 ,24 However, studies of surgical procedures for GTPS have been found to be small and difficult to interpret.23 Outcome measures are essential in evaluating the effectiveness of treatment. Measures used for GTPS are numerous and include pain scores, clinical findings, patient-reported outcomes and quality-of-life questionnaires. At present, there is no agreed gold standard outcome measure.
A recent review25 on GTPS identified a lack of evidence, recommending an approach including load management on the tendons and education. No previous systematic review solely focuses on conservative treatments for GTPS. Historically, methodological quality and risk of bias are terms that have been used interchangeably (JPT Higgins, S Green, eds. Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 [updated March 2011]. The Cochrane Collaboration, 2011. http://www.cochrane-handbook.org). It has been previously suggested that appraisal of methodological quality is essential;26 however, assessing risk of bias is fundamental in a review to ascertain whether a study's findings should be believed (JPT Higgins, S Green, eds. 2011. http://www.cochrane-handbook.org). None of the most recent systematic reviews on GTPS3 ,23 ,25 ,27 evaluate the risk of bias of the included studies, with only one review23 assessing methodological quality, this review using the Coleman Index score.
Aim of study
The aim of this systematic review was to evaluate the effectiveness of conservative treatments for GTPS, assessing the risk of bias of the included studies.
Methods
Search strategy
A search was conducted on 13 January 2016 for relevant studies published in MEDLINE, CINAHL, AMED and EMBASE with no limit on year of publication. A comprehensive search was undertaken using a combination of keywords and MeSH terms. How these terms were combined is displayed in table 1.
Search strategy showing the terms used and how terms were combined
Study selection
Inclusion and exclusion criteria
Inclusion and exclusion criteria (table 2) were determined prospectively. Articles were confined to English language only, due to costs associated with translation. All patients must have received a diagnosis of GTPS or trochanteric bursitis, while patients having undergone previous surgery, such as total hip replacement, were excluded as this introduces another potential cause for the symptoms. Other differentials were excluded, as displayed in table 2.
Inclusion and exclusion criteria
Shortlisting studies
Two authors (PAB and AN) independently shortlisted articles by reviewing the abstracts. If abstracts were not available, or if the abstract provided insufficient detail to inform a decision, the full article was obtained and independently reviewed by each author. To reduce bias, the authors (PAB and AN) discussed the shortlisted articles. In the case of disagreement, one author (NB) had the deciding vote. The reference list of all previous literature reviews on this topic, and of all the selected articles, were reviewed by two authors (PAB and NB) to ensure that all articles had been identified.
Risk of bias
We chose to assess the risk of bias as recommended by The Cochrane collaboration (JPT Higgins, S Green, eds. 2011. http://www.cochrane-handbook.org). Material bias is defined as ‘bias of sufficient magnitude to have a notable impact on the results or conclusions of the trial’ ((JPT Higgins, S Green, eds. 2011. http://www.cochrane-handbook.org), chapter 8.5.3). The Cochrane Risk of Bias tool (JPT Higgins, S Green, eds. 2011. http://www.cochrane-handbook.org) and The Cochrane Risk of Bias Assessment Tool for Non-Randomised Studies of Interventions (ACROBAT-NRSI) (JAC Sterne, JPT Higgins, BC Reeves, on behalf of the development group for ACROBAT-NRSI. A Cochrane Risk of Bias Assessment Tool: For Non-Randomized Studies of Interventions (ACROBAT-NRSI), Version 1.0.0. The Cochrane Colloquium, 2014. http://www.riskofbias.info (accessed 12 Nov 2015)) were used to assess the potential risk of bias of the included randomised controlled trials (RCTs) and cohort/case–control studies respectively. The guidance for making judgements are in online supplementary appendices 1 and 2.
Supplementary appendix 1
Supplementary appendix 2
For RCTs, there were seven domains, the judgements for each domain being either a ‘low risk’, ‘high risk’ or ‘unclear risk’ of material bias (see online supplementary appendix 1). Six domains were assessed, the seventh domain ‘Other sources of bias’ was not required because the three included studies were sufficiently assessed using the previous six domains, with no outstanding areas of potential risk of bias being identified.
For the ACROBAT-NRSI, there were seven domains (see online supplementary appendix 2), the judgements for each domain being ‘no information’, or a ‘low’, ‘moderate’, ‘serious’ or ‘critical’ risk of bias. Unlike the tool for RCTs, the ACROBAT-NRSI incorporated an assessment for the overall risk of bias, determined by criteria set out in the tool guidance notes (see online supplementary appendix 3), based on the domain judgements for that particular study.
Supplementary appendix 3
For the ACROBAT-NRSI, three key areas were examined prior to completing the tool proper, namely effect of interest, confounding and cointerventions. Confounding factors are prognostic factors for GTPS that also predict whether an individual receives one or other treatment intervention of interest (JAC Sterne, et al. The Cochrane Colloquium, 2014). Prognostic factors were high baseline disability,28 long duration of symptoms prior to intervention,2 ,28 higher initial pain intensity,28 older age,28 OA,2 previous treatment2 and general health issues such as diabetes mellitus29 and hypercholesterolaemia.30 ,31 Lievense et al2 found that patients with osteoarthritis were 4.8 times more likely to have symptoms at 1 year, while patients that had previously received injections for GTPS were 2.7 times more likely to recover at 5 years. Cointerventions included analgesia, further treatment modalities sought during the study period, including stretches that could cause tendon compression,32 ,33 and advice on rest.34 Confounding and cointerventions were discussed, using the tables in the guidance notes (JAC Sterne, et al. The Cochrane Colloquium, 2014) to determine the potential impact on the study being assessed, to ensure that the treatment effect being reported can be attributed to the primary intervention. Subjectivity is involved in any judgement, thus to minimise the risk of introducing bias, the tool was piloted prior to completion. Two authors (NB and AN) independently reviewed each study, comparing their findings, with any discrepancies being resolved by the third reviewer (PAB).
Data extraction and synthesis
One author (PAB) extracted data using a standardised form for each of the following: study design, sample size, demographics, diagnostic criteria, intervention details, outcome measures and follow-up frequency. This was verified by a second author (NB).
All data were synthesised descriptively; meta-analysis or a ‘Best Evidence Synthesis’ approach35–37 could not be performed due to the heterogeneity of the included studies. The included RCTs were supplemented by lower quality non-randomised studies, all studies meeting or exceeding the predetermined level being included, to reduce the risk of introducing bias. This risk was minimised further by the lower quality studies only being able to increase the strength of evidence if the findings are consistent with the higher quality studies.37
Results
Study selection
The study selection process is illustrated in figure 1.
Study selection process.
Summary of studies
In total, eight studies38–45 were included; two RCTs,38 ,39 one quasi-RCT,40 one case–control study,41 two prospective cohort studies42 ,43 and two retrospective cohort studies.44 ,45
The total number of patients was 696, with sample sizes ranging from 15 to 229 patients,40 ,45 with a mean age ranging from 39 to 66.2 years42 ,43 in 7 studies, while 1 study stated the median age of 53.44 All eight studies38–45 had a predominance of women, with the lowest proportion being 33% men: 67% women41 and the highest being 12% men: 88% women.42
Diagnosis
Diagnosis was based on a minimum of two criteria (see online supplementary appendix 4). The essential criteria common across all included studies was lateral hip pain.38–45 In addition, six studies required tenderness on palpation of the greater trochanter.38–40 ,42–44 One study38 required only these two diagnostic criteria, the remaining seven studies39–45 required additional clinical findings. Conflicting diagnostic criteria were observed between studies, with two studies41 ,45 requiring pain-free hip rotations, while two other studies39 ,43 identified pain on hip rotations as one of a number of potential requirements.
Supplementary appendix 4
Outcome measures
The studies included in this review used a variety of outcome measures. Six studies38–41 ,43 ,44 used VAS for pain and/or function, four studies38 ,40 ,41 ,43 recorded analgesic use and two studies39 ,42 used the Oswestry Disability Index (ODI). Other outcome measures, used in no more than one study, included EQ-5D,38 WOMAC,38 SF-36,39 Harris Hip Score41 and the Roles and Maudsley Score.41 Non-validated questionnaires were also used,43 while in one study,45 there were no stated outcome measures. Follow-up timescales ranged from 1 week to 79 months.
Risk of bias
All included studies demonstrated a number of risks of bias with the exception of the RCT by Cohen et al39 (table 3). The oldest study demonstrated greater risk of bias compared with all other included studies. Non-randomised studies (table 4) all demonstrated a higher risk of bias than RCTs.
Risk of bias for the selected randomised controlled trials
Risk of bias for all included non-randomised studies
Risk of bias for RCTs is displayed in table 3
Risk of bias for non-randomised studies is displayed in table 4
Management
Corticosteroid injections
One RCT38 and one quasi-RCT,40 both with a high risk of bias in one domain but a low risk of bias in all other domains, concluded that landmark-guided CSI demonstrated significant improvements in pain in the short term when compared with usual care, home training and radial shockwave therapy (RSWT). The landmark-guided CSI group demonstrated significant improvements compared with usual care at 3 months; however, at 12 months, there was no significant difference between groups;38 CSI was superior to RSWT and home training at 1 month, however at 15 months was inferior to home training.40 The benefit of landmark-guided CSI in patients with comorbidities was also shown to be slightly higher and statistically significant.38 One RCT,39 with a low risk of bias, compared landmark-guided with fluoroscopy-guided CSI, concluding that at 3 months, fluoroscopy-guided injections were not associated with superior outcomes. One study, demonstrating an overall moderate risk of bias, investigated ultrasound-guided CSI,44 concluding that ultrasound-guided injections into the greater TB may be more effective than subgluteus medius bursa injections, at least in the short-term treatment of GTPS.
The studies included in this review administered steroid dosages ranging from 6 to 60 mg39 ,43 (see online supplementary appendix 5). Shbeeb et al43 concluded that the 24 mg betamethasone dose was more likely to have a sustained improvement at 26 weeks, this study demonstrating an overall moderate risk of bias. The use of local anaesthetic (LA) was variable (see online supplementary appendix 5), with one study not using LA,42 while the remaining five studies used different anaesthetics, volumes and doses. Postinjection advice documented was limited. The immediate postinjection advice given was not documented in any of the included studies. Only one quasi-RCT40 advised all patients to avoid pain-provoking activities for 6 weeks then advised a slow return to sports thereafter.
Supplementary appendix 5
Shockwave therapy
RSWT was examined in two studies.40 ,41 Based on the Numerical Rating Scale for pain, one quasi-RCT40 demonstrated that RSWT was superior to CSI and home training at 4 months, was inferior to CSI at 1 month and no significant difference to home training at 15 months. This study demonstrated a high risk of selection bias (table 3), as there was sequential allocation to groups. A further study41 demonstrated better outcomes, based on the mean VAS, for RSWT at 1, 3 and 12 months compared with the control group, with only one treatment. However, this study demonstrated an overall serious risk of bias (table 4).
Home training
Home training (exercise therapy) was only examined in one study.40 Based on the outcome measure of pain, home training was shown to be superior to CSI at 15 months, no statistical difference was demonstrated at 4 months, and was far inferior to CSI at 1 month. Home training was inferior to RSWT at 4 months, while at 15 months, no significant difference was demonstrated. There was a high risk of selection bias; however, this study scored a low risk of bias in all other areas (table 3).
Discussion
This systematic review summarises the results of eight studies that have evaluated the effects of conservative treatments for GTPS. It has suggested that, in relation to pain, CSI give far superior outcomes at 1 month when compared with RSWT or home training, although there was a high risk of selection bias in that study. CSI demonstrated superior outcomes compared with usual care at 3 months; however, no significant difference was demonstrated between CSI and usual care at 12 months, although this study was found to have a high risk of detection bias. Furthermore, the benefit of CSI in patients with comorbidities was also shown to be slightly higher and statistically significant. Fluoroscopy-guided injections provided no additional benefit to landmark-guided injections at 3 months in a study with a low risk of bias. CSI dosage was not standardised, with one study that demonstrated an overall moderate risk of bias concluding that 24 mg betamethasone dose was more likely to have a sustained improvement at 26 weeks. Furthermore, the type, volume or strength of LA used was not standardised. RSWT was superior to CSI and home training at 4 months; however, no significant difference was found compared with home training at 15 months, while RSWT and home training were superior to CSI at 15 months. Again this study was found to have a high risk of selection bias but a low risk in all other areas (table 3). Another study found RSWT superior to a control group at 1, 3 and 12 months; however, this study was found to have an overall serious risk of bias (table 4).
Risk of bias
The risk of bias for the included RCTs was found to be lower than for non-randomised studies. The oldest study demonstrated greater risk of bias compared with all other included studies, one explanation being the improvements in journal reporting standards. Comparison of this review with systematic reviews on other tendinopathies is problematic, due to these reviews largely assessing methodological quality,46–49 the Cochrane collaboration recommending against the use of these tools displaying numerical scores (JPT Higgins, S Green, eds. 2011. http://www.cochrane-handbook.org). One review50 only used the RCT risk of bias tool on two studies, both having comparable risk of bias to the included studies in this review. For non-randomised studies, however, they assessed methodological quality. Another review evaluating rotator cuff tendinopathy51 used the risk of bias tool as part of the study selection, only including those studies at low risk of bias, improving the quality of the review findings. Assessment of risk of bias is central to any systematic review and plays an important role in assessing the strength of the evidence; however, it is important to note that a study can have a low risk of bias but demonstrate suboptimal quality in terms of treatment protocol.
Management
Corticosteroid injections
These studies suggest that CSI give superior outcomes in relation to pain in the short term, but not in the long term. These findings are similar to those in other tendinopathies such as tennis elbow.52 ,53 Fluoroscopy-guided injections were not associated with superior outcomes compared with landmark-guided CSI at 3 months.39 In the landmark-guided injection group, 11 injections were found to be intrabursal and 21 were extrabursal. The landmark-guided injection group had a successful outcome in 22 patients at 1 month and 15 patients at 3 months. This suggests that accuracy in relation to injecting the bursa is not a necessity to achieve short-term improvements in pain, supporting the fact that GTPS is not purely a bursitis.6–10 One study44 suggested that ultrasound-guided injections into the greater TB may be more effective than into the subgluteus medius bursa, at least in the short term. However, this study was limited by small sample sizes, different group sizes and a short follow-up period. Technique for landmark-guided injections is relatively standardised. Not all included studies,38 however, required the needle to touch bone prior to withdrawing. Particularly in patients with greater adiposity, longer needles may be required to achieve this; however, only two studies40 ,43 described this in their methodology.
Variation was noted in steroid dosages. There is, however, a paucity of research investigating the effectiveness of various dosages. One factor to consider regarding the dose of steroid would be patient habitus; therefore, the notion of ‘one dose fits all’ may be somewhat naïve and is potentially lacking in clinical reasoning. CSIs have also been associated with tendon degeneration and rupture54 so could dosage affect that risk? The use of LA was also variable with some not using LA, and those that did, using different volumes and types of anaesthetic. In one animal study, bupivacaine was shown to decrease proteoglycan synthesis at 6 hours post-injection but restored to normal at 72 hours,55 which could impact on tendon response. Some studies attributed this to the saline solution,55 ,56 while others suggested bupivacaine was not quite as benign as documented in previous studies.57 Negative effects of chondrotoxicity have also been shown.58–60 Whether LA has a therapeutic value for tendons remains to be proven. A recent study on lateral epicondylitis61 demonstrated CSI to be far superior to LA injections, based on the quick-DASH and VAS outcome measures. In contrast, a study on chronic rotator cuff tendinosis reported no significant difference in quality of life scores at 6 months between the LA injection group and a combined steroid and LA injection group.62 Negative effects of injections, however, should be considered, potentially influencing the postinjection advice given to patients. There is no documented gold standard regarding postinjection advice. Certainly, the results from one study55 suggest that the 72 hours postinjection could be crucial to minimise the risk of adverse effects from LA. The immediate postinjection advice given was not documented in any of the included studies, this advice having the potential to influence patient outcomes. The only study to document advice40 instructed all patients to avoid pain-provoking activities for 6 weeks then advised a slow return to sports thereafter. It is conceivable that both ends of the spectrum, namely rest and sudden overload, could result in a reactive tendinopathy.34
Home training
One study40 investigated home training (exercise), which consisted of piriformis and iliotibial band (ITB) stretches, along with strengthening exercises for gluteus maximus, quadriceps and a combined adductor and gluteal exercise. There were no specific exercises targeting gluteus medius or minimus within this exercise protocol. Neither were there many exercises addressing the kinetic chain, the importance of the kinetic chain having been demonstrated in other areas, such as the knee and shoulder.63–66 Improved neuromuscular performance has been shown to improve clinical outcomes.67 Managing the load on the tendon is important25 when using exercise therapy. To suitably address the needs of the individual, load setting needs to be patient specific to ensure that it is adequate and appropriate. There was no evidence of this in the included study. Furthermore, compression is a commonly acknowledged risk factor for tendinopathies.32 ,68–73 ITB stretching actually increases compression of the tendon by the greater trochanter, potentially aggravating symptoms. In a recent review, it was suggested that this should be avoided.33 Chronicity could also help to determine the appropriate exercises for the stage of tendinopathy,34 from isometric exercises in reactive tendinopathies, omitting any element of energy storage and release (stretch-shorten cycles), through to heavy slow resistance training74 ,75 and eccentric exercise in less irritable tendinopathies. Whether eccentric exercise is more or less effective than other forms of exercise in GTPS remains unproven. In patients with subacromial impingement syndrome, no difference was found between eccentric and concentric exercises.76 Advice regarding return to sport also requires greater specificity to avoid any sudden change in demand on the tendons. Further studies, with a more evidence-based treatment protocol, taking into consideration the latest developments in tendinopathies, are recommended.
Shockwave therapy
From the included studies, RSWT demonstrated promising results in the midterm (4 months); however, the associated risk of bias in both studies, particularly regarding selection bias, influences the strength of the findings. A review into extracorporeal shockwave therapy for patella tendinopathy77 concluded that results were promising. However, all studies demonstrated methodological deficiencies and issues with small sample sizes and/or short follow-up. In studies of lateral epicondyle tendinopathy, one demonstrated success,78 while others failed to demonstrate an effect.79 ,80 A review on non-operative treatments of midportion Achilles tendinopathy concluded that there was more evidence to support eccentric exercise than any other intervention and that ESWT showed promise in early studies; however, in one positive study, methodological concerns were again raised. There is a paucity of research on RSWT and GTPS. The National Institute for Clinical Excellence (NICE) interventional procedure guidance81 currently only recommends RSWT under special arrangements due to evidence on the efficacy and safety being limited in quality and quantity. NICE encourages further research into RSWT for refractory GTPS, with outcomes of function and quality of life scores, with at least 1 year follow-up.81 The Assessment of Effectiveness of Extracorporeal Shock Wave Therapy for Soft Tissue Injuries (ASSERT) database82 has been set up to address this. Certainly, in clinical practice, RSWT is less available and more resource intensive compared with home training. Further research is required before any firm conclusions can be drawn in relation to GTPS.
Orthotics
Only one study investigated the effectiveness of orthotics,42 but the serious risk of bias makes the study too problematic to provide any useful evidence regarding the use of orthotics. In studies that report leg length inequality, no association with GTPS has been identified.83 ,84 Further research is required before conclusions can be drawn.
Limitations
The limitations of this systematic review include an overall paucity of high-quality studies. If more high-quality studies were available, conclusions could be based purely on studies with a low risk of bias, improving the quality of the findings of this review. Furthermore, if there were a greater number of studies, a more comprehensive synthesis of the results could have been applied, using meta-analysis or the best evidence synthesis approach. Only English language publications were included, which introduces publication bias;85 however, this decision was necessary due to costs associated with translations. Further publication bias can be present due to difficulty in publishing papers which do not have a positive result. There is an element of subjectivity when one assesses the risk of bias, so where possible, guidance was taken from Cochrane publications. Decisions were also made using a third reviewer to further minimise this risk.
Diagnostic criteria
Effective treatment relies on accurate diagnosis.86 There were variations in the diagnostic criteria across the included studies, which has the potential to affect the evaluation of treatment effectiveness, due to the inclusion of patients whose symptoms may be arising from other comorbidities, and also the risk of bias. One study38 assessed clinically for hip OA; however, low back pain was assessed by questionnaire. The absence of clinical examination for LBP casts uncertainty on whether these patients were truly suffering from GTPS. Consequently, conclusions on treatment effectiveness are potentially erroneous because it could be argued that differential diagnoses have not been thoroughly excluded. Although hip OA could be considered a confounding factor, randomisation was stratified by comorbidity, therefore equal among groups, thus reducing the risk of bias. However, if this was a non-randomised study, then certainly, the diagnosis could negatively impact on study bias. Earlier studies based diagnostic criteria on Little;87 however, a more recent study, which set out to define the clinical presentation of GTPS, suggests that patients are likely to have GTPS if there is lateral hip pain, pain on palpation of the greater trochanter and FABER test reproducing lateral hip pain, with no difficulty manipulating shoes and socks.86 Standardisation of diagnostic criteria would help to exclude misdiagnosed or unrecognised disorders masquerading as GTPS,86 consequently improving clinical practice and research.
Outcome measures
There was great variation with regard to outcome measures used, the variability of which makes reviewing the literature challenging. Pain was consistently used in all studies, although there was variation within this. Numerous patient-reported outcome measures were used, not all of which were validated and some that were validated for back pain rather than hip pain or GTPS. Poorly chosen outcome measures make results less meaningful and/or misleading. Furthermore, one measure alone may not provide enough information to inform a decision; therefore, a combination of measures may be required. GTPS has been shown to have a significant impact on quality of life;88 therefore, pain data alone are not sufficient to evaluate treatment effectiveness. NICE81 support this, having recommended functional and quality-of-life outcome measures, with at least a 1 year follow-up when investigating RSWT. It is well recognised that an outcome measure must have the ability to detect change.89 Recently, the VISA-G has been shown to be a valid and reliable score for measuring the severity of disability associated with GTPS.90 Standardisation of outcome measures, which are validated and reliable, would enable meta-analysis and improve the quality of future systematic reviews.91
Implications for clinical practice
Diagnostic criteria should be standardised and the use of the VISA-G outcome measure should be encouraged. For improvements in pain, CSIs have been shown to be superior in the short term (<3 months), however are inferior to home training long term. Consideration should be given to adding home training to CSI, to potentially improve their longer term outcomes. This review could not draw conclusions on RSWT; however, it is important to note that NICE guidance in England recommends that RSWT should only be used under special arrangements, due to evidence on the efficacy and safety being limited in quality and quantity, however encourages further research into RSWT for refractory GTPS.
Implications for future research
More high-quality RCTs (following the CONSORT guidelines) and high-quality cohort controlled trials are needed to further evaluate the conservative treatments for GTPS. Based on the best available evidence, diagnostic criteria should be: lateral hip pain, pain on palpation of the greater trochanter and FABER test reproducing lateral hip pain, with no difficulty manipulating shoes and socks.86 The VISA-G is the only condition-specific and validated outcome measure for GTPS; therefore, its use should be encouraged. Standardisation of diagnostic criteria and outcome measures is essential and would enable more powerful analysis. There is a notable lack of research into exercise for GTPS, particularly considering their demonstrated superiority in other tendinopathies.
Further research should use the above recommendations and should focus on more specific tendinopathy-based rehabilitation protocols for GTPS, including isometric exercise, heavy slow resistance training and eccentric exercises. The staging of tendinopathy and implications on exercise selection is another area that requires further investigation.
Conclusion
This review demonstrates a paucity of high-quality research for the conservative treatments of GTPS. The risk of bias was only low in one study which demonstrated there was no additional benefit with fluoroscopically guided injections. Risk of bias in all remaining studies was varied. CSI demonstrated superior outcomes for up to 3 months, two studies on RSWT suggested promise at 4 and 15 months, albeit with one study having a serious risk of bias, while home training showed promise at 15 months. Standardisation of diagnostic criteria and outcome measures is essential to enable more powerful analysis, ensuring future studies demonstrate a low risk of bias.
What are the findings?
Need standardised diagnostic criteria.
Condition-specific outcome measures should be used, whether they should be used as stand-alone measures or in conjunction with other measures remains to be seen.
Risk of bias needs to be considered to fully evaluate the findings of a study.
How might it impact on clinical practice in the future?
Encourages the use of VISA-G as a condition-specific outcome measure in clinical practice.
Improves clinician's information when counselling patients to enable them to make an informed decision on which treatment they would like to opt for.
Identifies that CSI may have better outcomes combined with other modalities, such as home training.
References
Footnotes
Twitter Follow Paul Barratt @P_Barratt
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.