Background Effective treatment of hip pain improves population health and quality of life. Accurate differential diagnosis is fundamental to effective treatment. The diagnostic criteria for one common hip problem, greater trochanteric pain syndrome (GTPS) have not been well defined.
Purpose To define the clinical presentation of GTPS.
Methods Forty-one people with GTPS, 20 with hip osteoarthritis (OA), and 23 age-matched and sex-matched asymptomatic participants (ASC) were recruited. Inclusion and exclusion criteria ensured mutually exclusive groups. Assessment: the Harris hip score (HHS), a battery of clinical tests, and single leg stance (SLS). Participants identified the site of reproduced pain. Analysis: Fisher's exact test, analysis of variance (ANOVA) informed recursive partitioning to develop two classification trees.
Results Maximum walking distance and the ability to manipulate shoes and socks were the only HHS domains to differentiate GTPS from OA (ANOVA: p=0.010 and <0.001); OR (95% CI) of 3.47 (1.09 to 10.93) and 0.06 (0.00 to 0.26), respectively. The lateral hip pain (LHP) classification tree: (dichotomous LHP associated with a flexion abduction external rotation (FABER) test) had a mean (SE) sensitivity and specificity of 0.81 (0.019) and 0.82 (0.044), respectively. A non-specific hip pain classification tree had a mean (SE) sensitivity and specificity of 0.78 (0.058) and 0.28 (0.080).
Conclusions Patients with LHP in the absence of difficulty with manipulating shoes and socks, together with pain on palpation of the greater trochanter and LHP with a FABER test are likely to have GTPS.
- Hip disorder
- Lower limb quadrant related to injuries
- Soft tissue injuries
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Effective treatment of hip pain is likely to improve the health of the older population.1 Effective treatment is dependent upon accurate differential diagnosis, in particular between hip osteoarthritis (OA) and other hip conditions. Clinical criteria (eg, hip pain and (a) hip medial rotation (MR) ≤15° and hip flexion ≤115° or (b) hip MR>15° with associated pain, and ≤60 min of morning stiffness in people ≥50 years of age) for the purpose of defining hip OA were reported in 1991,2 these have been used extensively since.3 One common non-arthritic hip condition, greater trochanteric pain syndrome (GTPS)4 has symptoms common with hip OA and should be considered as an important differential diagnosis as diagnosis is commonly missed2 ,5 ,6 and treatment strategies very different. Recent attempts to refine the clinical presentation and the symptoms of GTPS have had limited success.7–9
A history of lateral hip pain (LHP) and pain on palpation of the lateral hip are consistently reported as signs and symptoms of GTPS.10–15 Other symptoms reported include pain with weight-bearing activities6 ,11 ,12 and pain with lying on the side at night.12 ,16 However, LHP can be referred from the hip joint17 ,18 and does not clearly differentiate GTPS from hip OA.2
Clinical tests to diagnose GTPS appear to have limited validity.7 Trendelenburg's sign, passive hip rotation and resisted hip abduction have low sensitivity and high specificity for tendinopathy.7–9 Passive lateral rotation is reported as ‘usually present’ in this population, suggesting a high sensitivity for GTPS.8 MRI has high sensitivity and low specificity. Unfortunately, MRI commonly reports asymptomatic disease.7 ,9 Resisted medial rotation may be a diagnostic test for GTPS but three different testing protocols have been evaluated.7–9 Tests such as active and passive movements appear to be of value in excluding hip joint pathology as a cause of LHP, rather than in diagnosis of GTPS.7 ,8 However, all these diagnostic tests have been evaluated in studies with methodological limitations such as a lack of a comparison symptomatic group, reliable criteria of the diagnosis of GTPS and exclusion of hip OA.
Therefore, the aim of this study was to define the clinical presentation of GTPS; to investigate if clinical history differentiates GTPS from the other common hip conditions found in the older population and to examine if a combination of clinical assessments tests differentiates GTPS from hip OA.
Patients and methods
A total of 84 consecutive consenting participants were prospectively recruited between March 2008 and November 2009. Forty-one participants had GTPS with mild-to-severe and recalcitrant symptoms, 23 were asymptomatic controls (ASC), age and sex matched to the GTPS participants and 20 were participants with OA of the hip awaiting hip arthroplasty. Hip OA participants were sex matched to 10 GTPS participants scheduled for tendon reconstruction surgery. Participants were over 18 years of age and able to communicate in English. Exclusion criteria for all groups were systemic inflammatory disease, lumbar spine nerve root signs, a history of lumbar spine or ipsilateral hip joint surgery, osteogenic disease (eg, Paget's disease or neoplasm), or a corticosteroid injection to the ipsilateral lateral hip region in the preceding 3 months.
Inclusion criteria for GTPS were a history of LHP,4 ,7–13 ,19 pain on palpation of the greater trochanter,4 ,8–11 ,13 ,20 ,21 and one or more of: LHP upon lying on the ipsilateral side,13 ,20 ,21 during weight-bearing activities6 ,11 ,20 or during sitting.11 Participants in the GTPS group with any signs or symptoms of OA hip were excluded. In two cases, x-rays revealed mild hip joint pathology. Subsequent ultrasound-guided local anaesthetic injection confirmed that lateral structures were responsible for the pain syndrome.8 One GTPS participant declined an x-ray, in this case, an MRI of the hip was used to evaluate the joint. Participants in the ASC groups were free of hip or thigh pain, and had no evidence of hip joint pathology on pelvic anterior−posterior x-ray.2 Participants in the OA group were diagnosed with hip OA according to Altman (1991).2 Participants in the ASC and OA groups had no history of GTPS, and no signs of symptoms of GTPS according to the above criteria.
Participants underwent a pelvic anterior−posterior x-ray to confirm the hip joint status.
Based on the above criteria seven people were excluded from the GTPS group; 16 were excluded from OA hip group; and 14 were excluded from the asymptomatic group.
This study was approved by university and hospital human research ethics committees, all participants provided informed consent.
The clinical assessment was performed on the day of recruitment, by an experienced physical therapist (AF). Assessment included a modified Harris Hip Score (HHS), a battery of passive and resisted tests (table 1)7 ,22–24 for which the reproduction and location of pain was recorded. Pain reproduction was categorised as non-specific hip pain (NHP), this included lateral, anterior and posterior hip pain, buttock and groin pain2 or LHP. LHP was defined as the area approximately 7 cm proximal and distal, and 3 cm anterior and posterior of the greater trochanter. A single leg stance (SLS) test was included.25 This was evaluated by trained, independent assessors viewing de-identified videos. All but three participants underwent all assessments. Two GTPS participants did not have assessor applied resistance tests. One OA participant was unable to lie on her back to undertake the range of movement test.
Statistical analyses were performed with Stata IC 10.1 (Statacorp, College Station, Texas, USA). Interval and ratio data were evaluated for group differences using one-way analysis of variance with post hoc Scheffe analysis. Since age is known to be associated with strength and gait variables, linear models were used to test group differences adjusting for age. Nominal data were evaluated using χ2, or Fisher exact where appropriate. Post hoc evaluation was undertaken by further χ2/Fisher exact testing on paired groups. P values of ≤0.05 were considered statistically significant. A post hoc evaluation of medial and lateral rotation, passive to active range of movement ratio was calculated. This allowed a dichotomised analysis based on a value of >1.5. Using recursive partitioning, two classification trees were produced. The reproduction of LHP was the basis of a positive test result for the first classification tree ‘LHP tree’. The reproduction of hip pain at any site was the basis of a positive test result in the second classification tree ‘NHP tree’. These trees identified clinical tests that best differentiated GTPS and hip OA participants. The ASC results were not included in this analysis. The clinical tests considered for this multivariate method are indicated in tables 3 and 4. Sensitivity and specificity of the classification trees were calculated using cross validation.2
The intrarater reliability for measuring the single leg stance had a range of intraclass correlation (ICC) (95% CI) of 1.0 to 1.0 (0.99 to 1.0). The inter-rater reliability was ICC (mean (SE))=0.99 (0.001).
Of the 84 participants, 80 (95%) were female with a mean (SD) age of 55.5 (12.7) years. The OA participants were older than the ASC participants, with a trend to OA participants being older than GTPS participants (table 2). The GTPS group had the highest rate of obesity (BMI> 30), followed by the OA group, and lastly the ASC group. In relation to precipitating events and duration of symptoms, there was no difference between the OA and GTPS groups (table 2).
The ASC had the highest HHS followed by the GTPS and the OA groups. The HHS of the ASC group was higher than both symptomatic groups (p<0.001), no difference was found between the two symptomatic groups (p=0.132, see online supplementary table S1). The HHS maximum walking distance and the ability to manipulate shoes and socks were the only domains that differentiated between the two symptomatic groups (p=0.010 and <0.001, respectively). Dichotomising the maximum walking duration into more or less than half an hour resulted in an OR of 3.47 (95% CI 1.09 to 10.93) for having GTPS rather than hip OA. A positive response to difficulty with manipulating shoes and socks was associated with an OR of 0.06 (95% CI 0.00 to 0.26) for having GTPS rather than hip OA.
Tests that differentiated GTPS from hip OA were enhanced by the participant identifying the site of the reproduced pain. In this case, LHP produced by a FABER test was most strongly associated with GTPS: OR 43.7 (95% CI 8.9 to not calculable). LHP with a FABER test had a high sensitivity, specificity, positive and negative predictive value (table 3). Without identifying the site of hip pain (non-specific hip pain), a restricted and painful Ober test was most strongly associated with GTPS: OR 13.2 (95% CI 2.0 to >100). While the Ober test had a high specificity, it had a low sensitivity and low negative predictive value (table 4).
Single leg stance test (25). The ASC had the longest duration (mean (SEM), s): 24.7 (1.95), OA: 20.22 (2.17); GTPS: 18.76 (1.47), regression controlling for age, p<0.001. Post hoc analysis demonstrated a difference between the ASC and GTPS group (p=0.017) but failed to demonstrate a difference between the GTPS and OA, or the ASC and the OA.
Identifying the site of the reproduced pain resulted in a classification tree with one branch. This tree identified the FABER tests as the key test in differentiating GTPS from hip OA. This tree has a high sensitivity and specificity (figure 1). Without identifying the site of reproduced hip pain, a less concise classification tree was produced. This tree has a reasonable sensitivity, but a low specificity (figure 2).
We report that GTPS can be differentiated from hip OA based on two history questions; walking duration and ease of manipulation of shoes and socks; and one clinical test—the FABER test, paying attention to the location of pain reproduction. We propose that the clinical definition of GTPS should be a history of LHP and no difficulty with manipulating shoes and sock together with clinical findings of pain reproduction on palpation of the greater trochanter and lateral pain reproduction with the FABER test.
We report that the ability to manage shoes and socks manipulation without difficulty differentiates between GTPS and hip OA. Previous studies have noted that people with GTPS report pain with weight-bearing activities, night pain—with the greater trochanter frequently noted as the site of pain9 ,10 ,12 ,16 ,20 ,26 ,27; and getting in and out of the car.11 Further, crossing the legs and rising from sitting have also been reported as more problematic for people with GTPS than those with low back pain.27 Many of the aggravating factors noted for GTPS are common to OA hip.2 Unlike our study, none of the studies cited above provide a comparison with other hip joint pathologies.
The classification tree based on a reproduction of LHP demonstrated that for patients who are able to locate their hip pain, the FABER test differentiated between those with GTPS and those with hip OA. The classification tree that did not identify the location of reproduce hip pain was more complex and had a lower sensitivity and specificity. This suggests that people who have trouble identifying their hip pain location may have co-morbidities requiring clinicians to undertake further investigations to clarify the diagnosis. Previous studies of the FABER test using MRI as the reference standard,7 suggested the FABER test was of limited value, but the clinicians in that study rated the FABER test second only to palpation of the greater trochanter as a critical tool in making the diagnosis. We confirm that identifying the pain location in association with the FABER test provides a valuable clinical test.
We were surprised that the single leg stance test did not differentiate between the two symptomatic groups. Previous reports found the single leg stance test (or variation on it) were helpful in identifying those with tendon pathology.7–9 In these studies two reports had no comparison group, using MRI as the reference standard, and one report compared the test in those with GTPS to an asymptomatic group,8 which we also did. That study reported a high sensitivity and specificity for identifying GTPS via a timed SLS. We also found that the single leg stance test differentiated between the asymptomatic group and the GTPS group, but the SLS, as carried out in this study, did not differentiate between the two symptomatic groups. The SLS is compromised by pain and poor balance.28 Thus, the SLS is able to demonstrate that the individual has a problem that affects muscle function about the hip, probably due to pain, however, it does not differentiate between joint or soft-tissue-based pathology. In the presence of pain, the SLS test is of limited value in measuring dysfunction, and or no value in differentiating the diagnosis of hip pathology.
We recognise the limitations of this study, in particular, that there is a tension between having well-defined participant groups, and testing for differentiating signs that may be influenced by the inclusion and exclusion criteria. In this study, one of the inclusion criteria for the GTPS participants was a history of LHP.4, 7–9 ,13 By definition, the control groups could not have a history of LHP. However, this did not exclude them from having LHP reproduced by clinical tests—indeed this was not assessed for in the screening process. Likewise, passive medial hip rotation range of movement of <15° was an exclusion criterion for the GTPS and ASC participants, and an inclusion criterion for hip OA participants. This may have influenced the passive to active range of movement ratio result. However, active range of movement and lateral rotation were not included in the screening process. As a result of this tension, two sets of pain response tables and two classification trees were produced. It is apparent from these trees that pain location is helpful in the differential diagnosis of OA hip and GTPS. To provide further validity for these classification trees a study with blinded assessors and the use of local anaesthetic injections (as a reference standard) could be undertaken.
Given the previous level of acceptance of the symptom of LHP and the sign of pain on palpation of the greater trochanter, we recommend that the clinical syndrome of GTPS be defined as a history of LHP in the absence of difficulty with manipulating shoes and socks. Examination findings should be the reproduction of pain on palpation of the greater trochanter and a FABER test that reproduces LHP.
What this study adds
A clinical and research definition of greater trochanteric pain syndrome (GTPS).
This study provides clinicians with a history key and a clinical assessment key for differentiating GTPS from hip osteoarthritis (OA).
The ability to manipulate one's shoes and socks provides a useful question regarding differentiation of GTPS from hip OA
The flexion abduction external rotation (FABER), with reproduction of lateral hip pain, is a sensitive and specific test for GTPS compared to hip OA.
How might it impact on clinical practice in the near future
Clinicians can be more confident that they have made an accurate diagnosis of greater trochanteric pain syndrome (GTPS).
This will reduce the time taken to diagnose the problem and should result in less imaging expense.
The number of people who experience misdiagnosis will be reduced.
People with GTPS will get appropriate treatment. They will not be wrongly treated for osteoarthritis of the hip.
We gratefully acknowledge the assistance of Dr Al Burns BMBS, FRACS, Dr Damian Smith BMBS, FRACS, for their contribution to participant recruitment, and Mr Simon Gallant for producing the figures.
This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.
Files in this Data Supplement:
- Data supplement 1 - Online Table
Contributors Study design and concept development by AF, JC, JS, PS (WC); participant recruitment by AF, JS, PS (AB, DS); data collection by AF (JS); data analysis by AF, TN; data interpretation by AF (JC, JS, PS, WC); manuscript writing by AF, JS, JC, PS (TN, WC); manuscript formatting by AF; and figure design by AF (SG).
Competing interests None.
Funding Angela Fearon was funded via a University scholarship. Jill Cook was supported by the Australian centre for research into sports injury and its prevention, which is one of the International Research Centres for Prevention of Injury and Protection of Athlete Health supported by the International Olympic Committee (IOC).
Ethics approval ACT Health Human Research Ethics Committee, Australian National University (ANU) Human Research Ethics Committee, Deakin University Human Research Ethics Committee.
Provenance and peer review Not commissioned; externally peer reviewed.
▸ References to this paper are available online at http://bjsm.bmj.com
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