The usefulness of ultrasound in predicting outcomes in patients with shoulder pain: a prospective observational study.

OBJECTIVES: Shoulder pain is common but current clinical classification has limited utility. We aimed to determine whether groups of ultrasound-based shoulder pathologies exist and to evaluate outcomes according to identified groups and individual pathologies. METHODS: Prospective study of a community-based cohort with shoulder pain referred for their first ultrasound scan at a single radiology unit, with subsequent routine clinical care. Patient-reported outcomes were collected at baseline, 2 weeks and 6 months; standardised ultrasound reporting was employed. Latent class analysis (LCA) identified ultrasound pathology-based groups. Multiple linear regression analysis explored associations between baseline pathologies, subsequent treatment and shoulder pain and disability index (SPADI). Short-term response to corticosteroid injections was investigated. RESULTS: Of 500 participants (mean age 53.6; 52% female), 330 completed follow-up. LCA identified 4 groups: bursitis with (33%) or without (27%) acromioclavicular joint degeneration, rotator cuff tear (21%), no bursitis/tear (19%). Total SPADI was higher at baseline for cuff tears (mean 55.1 vs 49.7-51.3; overall p= 0.005), but accounting for this, groups did not differ at 6 months (43.5 vs 38.5-40.5; p= 0.379). Baseline SPADI was the only predictor of 6-month SPADI retained by penalised modelling; neither LCA-derived US groups nor individual pathologies were selected. Response to baseline injection at week 2 did not differ between groups (mean SPADI 40.1-43.8; p= 0.423). CONCLUSION: Ultrasound-based classification (groups or individual pathologies) of shoulder pain did not predict medium-term outcomes using current treatments. The role of routine diagnostic ultrasound for shoulder pain needs consideration; it may be useful if evidence-based therapies for specific pathologies are established.

Chondroblastoma Affecting the Apophysis of the Greater Trochanter in a Child.

Chondroblastomas are rare primary bone tumours typically affecting the epiphyses and less frequently the apophyses of the growing skeleton. Most cases are treated by intralesional curettage with or without local adjuvants and this technique can produce good long-term outcomes. Herein, we describe a case of chondroblastoma of the greater trochanter in a 12-year-old male child that was treated by intralesional curettage and grafting with calcium phosphate bone cement (Neocement Inject® P, Bioceramed, Loures, Portugal). A brief review of the literature is also presented.

MRI Digital Artery Volume Index (DAVIX) as a surrogate outcome measure of digital ulcer disease in patients with systemic sclerosis: a prospective cohort study.

BACKGROUND: Vascular fibrosis is a key manifestation of systemic sclerosis that leads to the narrowing of small and medium arteries, causing vascular clinical manifestations including digital ulcers and pulmonary arterial hypertension. We investigated the potential of the MRI-based Digital Artery Volume Index (DAVIX) as a surrogate outcome measure of vascular fibrosis by using it to quantify and predict the burden of digital ulcer disease in patients with systemic sclerosis. METHODS: Two independent cohorts of patients participating in the prospective observational study STRIKE were consecutively enrolled from the Scleroderma Clinic of the Leeds Teaching Hospitals Trust, Leeds, UK. Eligible patients were aged 18 years or older and fulfilled the very early diagnosis of systemic sclerosis (VEDOSS) or the 2013 American College of Rheumatology (ACR)-European Alliance of Associations for Rheumatology (EULAR) systemic sclerosis classification criteria. DAVIX was calculated as the percentage mean of the ratio of digital artery volume to finger volume in the four fingers of the dominant hand. Data were collected at baseline and 12-month follow-up, and the primary outcome was the presence of digital ulcers at 12-month follow-up. FINDINGS: Between Feb 7, 2018, and April 11, 2022, we included 85 patients in the exploratory cohort and 150 in the validation cohort. In the exploratory cohort, the mean age was 54·5 years (SD 11·6), 75 (88%) of 85 patients were women, ten (12%) were men, and 69 (82%) were White. In the validation cohort, the mean age was 53·5 years (SD 13·8), 136 (91%) of 150 patients were women, 14 (9%) were men, and 127 (85%) were White. In the exploratory cohort, DAVIX was significantly lower in patients with previous or active digital ulcers (0·34% [IQR 0·16-0·69]) than in those without digital ulcer disease (0·65% [0·42-0·88]; p=0·015); this finding was substantiated in the validation cohort (0·43% [0·20-0·73] vs 0·73% [0·53-0·97]; p<0·0001). Patients who developed new digital ulcers during 12-month follow-up had a lower DAVIX (0·23% [0·10-0·66]) than those who did not (0·65% [0·45-0·91]; p=0·0039). DAVIX was negatively correlated with disease duration (r=-0·415; p<0·0001), the ratio of forced vital capacity to the diffusing capacity of the lungs for carbon monoxide (r=-0·334; p=0·0091), nailfold capillaroscopy pattern (r=-0·447; p<0·0001), and baseline modified Rodnan skin score (r=-0·305; p=0·014) and was positively correlated with the diffusing capacity of carbon monoxide (r=0·368; p=0·0041). DAVIX was negatively correlated with change in score on the Scleroderma Health Assessment Questionnaire-Disability Index (r=-0·308; p=0·024), Visual Analogue Scale (VAS) Raynaud's (r=-0·271; p=0·044), and VAS digital ulcers (r=-0·291; p=0·044). INTERPRETATION: DAVIX is a promising surrogate outcome measure of digital ulcer disease in patients with systemic sclerosis. The ability of DAVIX to non-invasively predict future digital ulcers and worsening of patient-reported outcomes could aid patient enrichment and stratification in clinical trials. Clinically, DAVIX could offer insights into the assessment of vascular activity. The sensitivity of DAVIX to change over time and with treatment will establish its value as an imaging outcome measure of vascular disease. FUNDING: National Institute for Health Research Biomedical Research Centre and University of Leeds Industry Engagement Accelerator Fund.

The capsular head of the proximal rectus femoris muscle: a review of the imaging anatomy of proximal muscle injury in professional athletes - early experience.

The detailed anatomy of the rectus femoris and corresponding injury appearances were first described in 1995. Since then, there has been little published to change our understanding of this complex anatomical area. More recent anatomical dissection work in 2004 and 2006 alluded to the presence of an altered configuration of the proximal tendon anatomy. Whilst widely accepted that the proximal rectus femoris muscle has two distinct tendon slips, the authors in 2006 described a third separate tendon slip arising from the anterior femoral capsule and this has been widely termed the 'capsular head'. We provide evidence that imaging features corroborate this revised anatomical concept. Whilst the clinical relevance of these findings is yet to be established, it remains important that our understanding of the radiological anatomy in this area advances with the forward growth of imaging clarity. In this review, we revisit anatomical concepts and present atypical injury cases that may be explained by the presence of a separate capsular head.

Reliability of slice-encoding for metal artefact correction (SEMAC) MRI to identify prosthesis loosening in patients with painful total hip arthroplasty - a single centre, prospective, surgical validation study.

OBJECTIVES: To validate reliability of slice-encoding for metal artefact correction (SEMAC)-MRI findings in prosthesis loosening detection by comparing them to surgical outcomes (gold standard) in symptomatic patients following hip arthroplasties. To evaluate periprosthetic anatomical structures in symptomatic patients to identify an alternative cause of hip symptoms. METHODS: We prospectively followed 47 symptomatic patients (55 hips, 39 painful hips - group P and 16 control hips - group C) at our institution from 2011 to 2016. We acquired 1.5 T MRI conventional and SEMAC-MRI images for all patients. Two consultants scored MRI for osteolysis and marrow oedema zone-wise using predefined signal characteristics and settled scoring variations by consensus. We used Spearman Rank-Order Correlation for correlation analysis and used OMERACT (Outcome Measures in Rheumatology) filter pillars to validate SEMAC-MRI findings. RESULTS: Eleven patients needed revision surgery, all from group P. None from group C required revision surgery. Remaining 28 hips in the group P were managed conservatively pain completely resolved in 21 hips, eight hips had trochanteric bursitis, eight had extraarticular cause and the remaining five hips had spontaneous pain resolution. We found moderate-to-weak correlation between SEMAC-MRI findings for prosthesis loosening and revision surgery outcomes. Sensitivity, Specificity, PPV and NPV in Group P were (72.7, 64.3, 44.4, 85.7%) in T1W-SEMAC, (90.9, 46.4, 40.0, 92.9%) in STIR-SEMAC and (36.3, 78.5, 40.0, 75.8%) in PDW-SEMAC. CONCLUSION: Negative SEMAC-MRI results can effectively exclude prosthesis loosening confirmed on revision surgery and SEMAC-MRI can detect alternative cause of hip pain accurately. ADVANCES IN KNOWLEDGE: Negative SEMAC-MRI in painful THA patients can effectively exclude prosthesis loosening as a cause.

Ultrasound evaluation of the rotator interval and adjoining tendons in shoulders with restricted movements: a technical note describing a simplified shoulder position.

The rotator interval (RI) is a critical but complex anatomical structure for which musculoskeletal ultrasound provides an excellent imaging evaluation. In the patients with restricted and painful movements, the RI may not be visualised optimally as the conventional 'Modified Crass' positions may not be achievable. It can also be difficult to optimally evaluate the anterior supraspinatus and subscapularis tendons in such patients. We describe a simple shoulder position obviating need of pronounced supraspinatus stretch for better evaluation of the rotator interval and adjoining rotator cuff structures.

The Evolving Roles of MRI and Ultrasound in First-Line Imaging of Rotator Cuff Injuries.

Rotator cuff tears are the most likely source of shoulder pain in adults and may cause protracted disability. Management of rotator cuff tears is associated with considerable costs. Accurate diagnosis can guide surgical planning and help achieve a favorable clinical outcome. Although radiography remains the initial imaging test for shoulder injury, the roles of MRI and ultrasound (US) as first-line imaging after radiography are evolving. This article leverages current literature and the practical experience of subspecialty musculoskeletal radiologists from different institutions in describing a practical approach to imaging rotator cuff pathology. Both MRI and US are accurate for identifying rotator cuff tears, but each has advantages and shortcomings. As both modalities currently represent reasonable first-line approaches, considerable practice variation has evolved. Given the low cost of US, imagers should strive to optimize the quality of shoulder US examinations and to build referrer confidence in this modality. The roles of direct CT and MR arthrography as well as imaging evaluation of the postoperative rotator cuff are also considered. Through careful selection among the available imaging modalities and optimal performance and interpretation of such examinations, radiologists can positively contribute to the diagnosis and treatment of patients with rotator cuff injuries.

Musculoskeletal ultrasound imaging standards in the UK: British Society of Skeletal Radiologists (BSSR) position statement.

There has been some concern expressed by UK regulator, the Professional Standards Authority regarding the risks arising from Independent sonographer practices. The Professional Standards Authority presented evidence demonstrating that there are instances of harm occurring because of errors made by non-radiologists performing musculoskeletal ultrasound (MSKUS), particularly MSKUS-guided interventions. This document summarises British Society of Skeletal Radiologists position for Musculoskeletal use of ultrasound in UK, representing the agreed consensus of experts from the British Society of Skeletal Radiologists Ultrasound committee. The purpose of this position statement is to review the current practices affecting the delivery of MSKUS. Recommendations are given for education and training, audit and clinical governance, reporting, and medicolegal issues.

Muscle stiffness in rheumatoid arthritis is not altered or associated with muscle weakness: A shear wave elastography study.

Objectives: To investigate muscle stiffness and strength in rheumatoid arthritis patients compared to healthy controls.Methods: A sample of 80 RA patients from three discrete groups: 1 - newly diagnosed treatment-naïve RA (n = 29), 2 - active RA for at least 1 year (n = 18) and 3 - in remission RA for at least 1 year (n = 33), was compared to 40 healthy controls. Shear wave velocity (SWV) was measured using shear wave elastography as a surrogate for tissue stiffness in multiple muscles. All participants performed isometric grip strength, timed get-up-and-go test, 30-s chair stand test and isokinetic knee extension/flexion (60°/s). The difference in SWV amongst the groups was tested using one-way ANOVA, and the correlation between SWV and muscle strength results were calculated using Pearson's coefficients.Results: The mean age ± SD was 61.2 ± 12.8 for RA patients and 61.5 ± 10.5 years for controls. SWV was not significantly different amongst the groups on all muscles (p > .05). In comparison to controls, the new and active RA groups showed a significantly lower isokinetic strength by -29% (p = .013) and -28% (p = .040), fewer chair stands by -28% (p = .001) and -44% (p < .001), longer walking times by -25% (p = .025) and -30% (p = .001), respectively, and weaker grip strength by -45% for both (p < .001). The muscle strength in the remission RA groups was not significantly lower, except in the isokinetic knee strength (-21%; p = .027). The correlations between SWE and the muscle assessment results were weak and insignificant (r < 0.30; p > .05).Conclusion: Significant muscle weakness was demonstrated in patients with RA disease. However, muscle stiffness was normal and not associated with muscle strength.

Reduction in stiffness of proximal leg muscles during the first 6 months of glucocorticoid therapy for giant cell arteritis: A pilot study using shear wave elastography.

AIM: To investigate muscle stiffness changes in patients treated for giant cell arteritis (GCA) with high-dose oral glucocorticoids. METHODS: Using ultrasound elastography, shear wave velocity (SWV) was measured in the quadriceps, hamstrings and biceps brachii muscles of 14 patients with GCA (4 male, mean age ± SD, 68.2 ± 4.3 years) within the first 2 weeks of initiating glucocorticoid treatment (baseline) and repeated after 3 and 6 months treatment. Muscle strength and performance tests were performed at each visit. Baseline measures were compared with those from 14 healthy controls. Linear mixed models were used to test for change in patient measures over time. RESULTS: At baseline, muscle SWV in patients was not significantly different from controls. With glucocorticoid treatment, there was a reduction in SWV in the leg but not the arm muscles. SWV decreased by a mean of 14% (range 8.3%-17.3%; P = .001) after 3 months and 18% (range 10.2%-25.3%; P < .001) after 6-months in the quadriceps and hamstrings during the resting position. The baseline, 3 and 6 months mean SWV (±SD) for the vastus lateralis were 1.62 ± 0.16 m/s, 1.40 ± 0.10 m/s and 1.31 ± 0.06 m/s, respectively (P < .001). In the patient group as a whole, there was no significant change in muscle strength. However, there were moderate correlations (r = .54-.69) between exhibiting weaker muscle strength at follow-up visits and a greater reduction in SWV. CONCLUSION: Glucocorticoid therapy in patients with GCA was associated with a significant reduction in proximal leg muscle stiffness during the first 6 months. Future research should study a larger sample of patients for a longer duration to investigate if diminished muscle stiffness precedes signs of glucocorticoid-induced myopathy.

The European Society of Skeletal Radiology Quiz 2018.

This article consists of a series of clinical cases presented during the ESSR Quiz session at the 25th Annual Meeting of the European Society of Musculoskeletal Radiology in Amsterdam 2018. The first section contains the clinical information and an initial set of images for each case. The second section reveals the answers along with additional imaging followed by a short discussion about the pathologic processes presented. This article provides self-assessment and at the same time refreshes the reader's knowledge about some common and not-so-common clinical conditions that a radiologist may encounter during clinical practice.

Muscle shear wave elastography in idiopathic inflammatory myopathies: a case-control study with MRI correlation.

OBJECTIVE: To investigate muscle stiffness in patients with idiopathic inflammatory myopathies (IIM) using shear wave elastography (SWE) and to correlate the results with muscle strength and MRI features of myositis. MATERIALS AND METHODS: Muscle shear wave velocity (SWV) was measured in 23 active IIM patients (13 females, mean age 50.4 ± 16.1 years) and 23 matched healthy controls (13 females, mean age 50.7 ± 16.2 years). The investigated muscles included the vastus lateralis (VL), rectus femoris (RF), vastus medialis (VM) vastus intermedius (VI), biceps femoris (BF), semitendinosus (ST), semimembranosus (SM) and the biceps brachii (BB) scanned during relaxed resting and passive stretching positions. Participants performed multiple tests to evaluate their muscle strength. IIM patients had a thigh MRI to assess degrees of oedema, fatty infiltration and atrophy. RESULTS: In the resting position, IIM patients had a 12.9-22.2% significantly lower SWV (p < 0.05) for the quadriceps and hamstrings, but not BB. There was no difference during passive stretching. The SWV for VL, VI and BF showed moderate correlations with the muscle strength tests ranging from r = 0.47 to r = 0.70 (all p < 0.05). Lower SWV was associated with greater MRI scores of oedema (p = 0.001) and atrophy (p = 0.006). However, SWV did not correlate with fatty infiltration (r < 0.3; p = 0.28), creatine kinase (r = 0.28; p = 0.19) or disease duration (r = 0.26; p = 0.24). CONCLUSION: Shear wave elastography may detect abnormal reduced thigh stiffness in IIM patients. SWE measurements were significantly associated with muscle weakness and MRI signs of oedema and atrophy. Future research should investigate this new technology for monitoring disease activity.

The effect of ageing on shear wave elastography muscle stiffness in adults.

BACKGROUND: Skeletal muscle undergoes structural changes with ageing which may alter its biomechanical properties. Shear wave elastography (SWE) may detect these changes by measuring muscle stiffness. AIMS: To investigate muscle stiffness in healthy young, middle-aged and elderly cohorts using SWE and correlate it with muscle strength and mass. METHODS: Shear wave velocity (SWV) was measured in the quadriceps, hamstrings and biceps brachii of 26 young (range 20-35 years), 21 middle-aged (40-55) and 30 elderly (77-94) volunteers. The participants performed several muscle tests to evaluate their strength. The One-way ANOVA was used to test the muscle stiffness differences between the groups and the Pearson's correlation coefficient to evaluate the relationship between SWV and muscle strength. RESULTS: The overall resting muscle SWV gradually decreased with age but was only significantly reduced in the elderly group (p < 0.001); with the exception of the vastus lateralis SWV where a significant difference was noted (p < 0.05) between young (1.77 m/s), middle-aged (1.64 m/s) and elderly (1.48 m/s). The elderly group had on average 16.5% lower muscle stiffness compared to the young. SWV significantly correlated with muscle mass (r = 0.316), walking time (r = - 0.560), number of chair stands (r = 0.522), handgrip strength (r = 0.436) and isokinetic knee strength (r = 0.640). Sex and BMI did not explain any significant variation in SWV. CONCLUSIONS: Ageing was associated with a decline in skeletal muscle stiffness which positively correlates with muscle weakness. Further research is needed to evaluate the promising role of SWE as a biomarker for sarcopenia assessment and potential falls risk prediction in elderly individuals.

The effect of unit, depth, and probe load on the reliability of muscle shear wave elastography: Variables affecting reliability of SWE.

PURPOSE: There is currently no standardized method for muscle shear wave elastography (SWE). The objective of this study was to investigate the effect of unit of measurement, depth, and probe load on the reliability of muscle SWE. METHODS: The vastus lateralis, biceps femoris, biceps brachii, and abductor digiti minimi muscles were scanned on 20 healthy participants. The SWE readings were measured in shear wave velocity (m/s) and Young's modulus (kPa). Three acquisitions of varying depths were acquired from vastus lateralis. Minimal probe load was compared with the use of a standoff gel layer. Three repeated measurements were acquired to assess reliability using intraclass correlations (ICC). RESULTS: The mean elasticity varied across muscle groups and ranged from 1.54 m/s for biceps femoris to 2.55 m/s for abductor digiti minimi (difference = 1.01 m/s [95% confidence interval, CI = 0.92, 1.10]). Reporting readings in meters per second resulted in higher ICC of 0.83 (0.65, 0.93) in comparison to 0.77 (0.52, 0.90) for kilopascal for the vastus lateralis muscle only. Variance increased proportionally with depth reaching 0.17 (equivalent to ±0.82 m/s) at 6 cm. Using a standoff gel decreased ICC to 0.63 (0.20, 0.84) despite similar mean elasticity readings to minimal probe load. CONCLUSIONS: Different acquisition and technical factors may significantly affect the reliability of SWE in skeletal muscles. Readings acquired in the unit of shear wave velocity (m/s) from depths less than 4 cm using a minimal probe load without a standoff gel yielded the best reliability.

An investigation into the variability between different shear wave elastography systems in muscle.

AIMS: The reliability and agreement between shear wave elastography (SWE) systems using different acquisition methods in muscles is not yet established. The objectives were to determine the reliability of a new SWE system on normal resting muscles using different acquisition methods and to compare its performance to an established state-of-the-art system. MATERIALS AND METHODS: Small, medium and large ROI sizes in addition to longitudinal, oblique and transverse orientations over five different locations within the rectus femoris muscle were tested using the new system. Results were compared to the established system to test for inter-system reproducibility. RESULTS: Lowest within-subject coefficient of variance (4.3%) andshear wave velocity (1.83 m/s) were associated with the medium ROI and longitudinal orientation from the lateral location. This combination resulted in a strong internal agreement of intra-class correlation of 0.76 (0.57-0.89) for the new system and an almost perfect agreement of 0.92 (0.82-0.97) for the established. Inter-system reproducibility for the best combination was 0.71 (0.48-1) with a mean velocity difference ±95% limits of agreement of 0.07±0.49 m/s. CONCLUSIONS: Altering SWE acquisition methods can produce variable results. The new system produced reliable results that are comparable with but not as reliable as the established.

Ultrasound-detected pathologies cluster into groups with different clinical outcomes: data from 3000 community referrals for shoulder pain.

BACKGROUND: Ultrasound is increasingly used to evaluate shoulder pain, but the benefits of this are unclear. In this study, we examined whether ultrasound-defined pathologies have implications for clinical outcomes. METHODS: We extracted reported pathologies from 3000 ultrasound scans of people with shoulder pain referred from primary care. In latent class analysis (LCA), we identified whether individual pathologies clustered in groups. Optimal group number was determined by the minimum Bayesian information criterion. A questionnaire was sent to all patients scanned over a 12-month period (n = 2322). Data collected included demographics, treatments received, current pain and function. The relationship between pathology-defined groups and clinical outcomes was examined. RESULTS: LCA revealed four groups: (1) bursitis with limited inflammation elsewhere (n = 1280), (2) bursitis with extensive inflammation (n = 595), (3) rotator cuff tears (n = 558) and (4) limited pathology (n = 567). A total of 777 subjects (33%) completed questionnaires. The median (IQR) duration post-ultrasound scan was 25 (22-29) months. Subsequent injections were most common in groups 1 and 2 (groups 1-4 76%, 67%, 48% and 61%, respectively); surgery was most common in group 3 (groups 1-4 23%, 21%, 28% and 16%, respectively). Shoulder Pain and Disability Index scores were highest in group 3 (median 48 and 30, respectively) and lowest in group 4 (median 32 and 9, respectively). Patients in group 4 who had surgery reported poor outcomes. CONCLUSIONS: In a community-based population, we identified clusters of pathologies on the basis of ultrasound. Our retrospective data suggest that these groups have different treatment pathways and outcomes. This requires replication in a prospective study to determine the value of a pathology-based classification in people with shoulder pain.

Recommendations of the ESSR Arthritis Subcommittee on Ultrasonography in Inflammatory Joint Disease.

This article presents the recommendations of the European Society of Musculoskeletal Radiology Arthritis Subcommittee on the use of ultrasonography (US) in rheumatic disease, focused on the examination of joints in the adult population. The recommended examination technique and protocols used in a radiologic work-up are discussed. The main US features that can lead to a final diagnosis in the most common rheumatic diseases are addressed. The differential diagnosis that should be considered at image interpretation is presented. The role of US in interventional procedures and clinically important recent developments is also discussed.

Hip morphology in elite golfers: asymmetry between lead and trail hips.

AIM: During a golf swing, the lead hip (left hip in a right-handed player) rotates rapidly from external to internal rotation, while the opposite occurs in the trail hip. This study assessed the morphology and pathology of golfers' hips comparing lead and trail hips. METHODS: A cohort of elite golfers were invited to undergo MRI of their hips. Hip morphology was evaluated by measuring acetabular depth (pincer shape=negative measure), femoral neck antetorsion (retrotorsion=negative measure) and α angles (cam morphology defined as α angle >55° anteriorly) around the axis of the femoral neck. Consultant musculoskeletal radiologists determined the presence of intra-articular pathology. RESULTS: 55 players (mean age 28 years, 52 left hip lead) underwent MRI. No player had pincer morphology, 2 (3.6%) had femoral retrotorsion and 9 (16%) had cam morphology. 7 trail hips and 2 lead hips had cam morphology (p=0.026). Lead hip femoral neck antetorsion was 16.7° compared with 13.0° in the trail hip (p<0.001). The α angles around the femoral neck were significantly lower in the lead compared with trail hips (p<0.001), with the greatest difference noted in the anterosuperior portion of the head neck junction; 53° vs 58° (p<0.001) and 43° vs 47° (p<0.001). 37% of trail and 16% of lead hips (p=0.038) had labral tears. CONCLUSIONS: Golfers' lead and trail hips have different morphology. This is the first time side-to-side asymmetry of cam prevalence has been reported. The trail hip exhibited a higher prevalence of labral tears.