Radiological investigations are essential in the work-up of patients presenting with non-arthritic hip pain, to allow close review of the complex anatomy around the hip and proximal femur. The aim of this study is to quantify the radiation exposure associated with common radiological investigations performed in assessing young adult patients presenting with non-arthritic hip pain. A retrospective review of our UK tertiary hip preservation centre institutional imaging database was performed. Data was obtained for antero-posterior, cross-table lateral and frog-lateral radiographs, along with data for the low dose CT hip protocol and the Mako CT Hip protocol. The radiation dose of each imaging technique was measured in terms of dose-area product (DAP) with units of mGycm2, and the effective doses (ED, mSv) calculated. The mean effective radiation dose for hip radiographs was in the range 0.03 to 0.83mSv (mean DLP 126.7–156.2 mGycm2). The mean effective dose associated with the low-dose CT hip protocol was 3.04mSv (416.8 mGycm2) and for the Stryker Mako CT Hip protocol was 8.4mSv (1061 mGycm2). The radiation dose associated with use of CT imaging was significantly greater than plain radiographs (p<0.005). Investigation of non-arthritic hip pain can lead to significant ionising radiation exposure for patients. In our institution, the routine protocol is to obtain an anteroposterior radiograph and then a specific hip sequence 3 Tesla MRI including anteversion views. This provides the necessary information in the majority of cases, with CT scanning reserved for more complex cases where we feel there is a specific indication. We would encourage the hip preservation community to carefully consider and review the use of ionising radiation investigations

Background. We herein report a case of isolated hip pain in a four year old boy. The unique aspect of this case study is the unusual history, presentation, ultrasonography, MRI and blood culture results, which lead to the diagnosis and treatment of adductor pyomyositis with a rare organism (Streptococcus Mitis) in a temperate country. The objectives of this case study is to discuss the key learning outcomes with respect to assessment and management of this case. Methods. The patient presented with a one day history of malaise, fever, left groin pain and inability to weight bear on the left leg. There was no history of any trauma, predisposing infections or recent travel. A working diagnosis of transient synovitis / septic arthritis of the hip was made on clinical examination. Results. Plain radiograph and ultrasound of the hip was normal with no effusion. Two consecutive blood cultures suggested Streptococcus Mitis bacteriaemia and MRI scan confirmed pyomyositis of the left hip adductors that was too small to drain. Streptococcus Mitis is a normal commensal organism of the oral cavity however it can lead to opportunistic infections particularly endocarditis. Echocardiogram revealed no cardiac complications, in particular no endocarditic vegetation. Patient was treated with intravenous benzylpenicillin for a week followed by oral phenoxymethylpenicillin for a week. Conclusion. Adductor pyomyositis must be considered as a differential diagnosis in a child with unusual presentation of hip pain. When an ultrasound is normal, MRI scan is warranted to confirm diagnosis. Septic screen should include blood cultures. The commonest causative organisms are the Staphylococcus family. However if Streptococcus Mitis is isolated, cardiac sources of infection resulting in septic emboli must be investigated. Repeated MRI scans are required particularly if the patient does not respond to medical management. Level of Evidence. IV

We herein report a case of isolated hip pain in a four year old boy. The importance of this project is the unusual history, presentation, ultrasound, MRI and blood culture results and treatment, which lead to the diagnosis of adductor pyomyositis with a rare organism (Streptococcus Mitis) in a temperate country. The patient presented with a one day history of malaise, fever, left groin pain and inability to weight bear on the left leg. There was no history of any predisposing infections or recent travel. A working diagnosis of transient synovitis / septic arthritis of the hip was made on clinical examination. Plain radiograph and ultrasound of the hip was normal with no effusion. Two consecutive blood cultures suggested Streptococcus Mitis bacteriaemia and MRI scan confirmed pyomyositis of the left hip adductors that was too small to drain. Streptococcus Mitis is a normal commensal organism of the oral cavity however it can lead to opportunistic infections particularly endocarditis. Echocardiogram revealed no cardiac complications, in particular no endocarditic vegetation. Patient was treated with intravenous benzylpenicillin for a week followed by oral phenoxymethylpenicillin for a week. As it was a soft tissue infection, a short course of antibiotics was sufficient and he made a complete recovery. Adductor pyomyositis must be considered as a differential diagnosis in a child with unusual presentation of hip pain. When an ultrasound is normal, MRI scan is warranted to confirm diagnosis. Septic screen should include blood cultures. The commonest organisms are the Staphylococcus family. However if Streptococcus Mitis is isolated, cardiac sources of infection resulting in septic emboli must be investigated. Repeated MRI scans are required particularly if the patient does not respond to medical management

Aims. The Single Assessment Numerical Evalution (SANE) score is a pragmatic alternative to longer patient-reported outcome measures (PROMs). The purpose of this study was to investigate the concurrent validity of the SANE and hip-specific PROMs in a generalized population of patients with hip pain at a single timepoint upon initial visit with an orthopaedic surgeon who is a hip preservation specialist. We hypothesized that SANE would have a strong correlation with the 12-question International Hip Outcome Tool (iHOT)-12, the Hip Outcome Score (HOS), and the Hip disability and Osteoarthritis Outcome Score (HOOS), providing evidence for concurrent validity of the SANE and hip-specific outcome measures in patients with hip pain. Methods. This study was a cross-sectional retrospective database analysis at a single timepoint. Data were collected from 2,782 patients at initial evaluation with a hip preservation specialist using the iHOT-12, HOS, HOOS, and SANE. Outcome scores were retrospectively analyzed using Pearson correlation coefficients. Results. Mean raw scores were iHOT-12 67.01 (SD 29.52), HOS 58.42 (SD 26.26), HOOS 86.85 (SD 32.94), and SANE 49.60 (SD 27.92). SANE was moderately correlated with the iHOT-12 (r = -0.4; 95% CI -0.35 to -0.44; p < 0.001), HOS (r = 0.57; 95% CI 0.53 to 0.60; p < 0.001), and HOOS (r = -0.55; 95% CI -0.51 to -0.58; p < 0.001). The iHOT-12 and HOOS were recorded as a lower score, indicating better function, which accounts for the negative r values. Conclusion. This study was the first to investigate the relationship between the SANE and the iHOT-12, HOS, and HOOS in a population of patients with hip pain at the initial evaluation with an orthopaedic surgeon, and found moderate correlation between SANE and the iHOT-12, HOS, and HOOS. The SANE may be a pragmatic alternative for clinical benchmarking in a general population of patients with hip pain. The construct validity of the SANE should be questioned compared to legacy measures whose content validity has been more rigorously investigated. Cite this article: Bone Jt Open 2024;5(10):904–910

Aim. This study aims to determine the value of MRI in children with hip pain which remained unexplained following routine investigations including ultrasound examination. Materials and methods. Retrospective review of clinical notes and MRI findings in all children who received and MRI scan for undiagnosed hip pain over three years. Results. Fifty five children underwent an MRI scan of their hips for unexplained hip pain. 29 were male and 26 were female. The mean age was 10.9 years. The MR study provided a diagnosis in 22 children (40%), and was normal in 33 children (60%). Five cases were considered to be due to transient synovitis. Three children were diagnosed as osteoid osteoma. Two children were were found to have trochanteric bursitis. Two children were shown to have muscle trauma (one child with adductor trauma and one child with piriformis trauma). Two children were diagnosed with non-specific bone oedema. The remaining eight children were diagnosed with Perthes' disease, haemarthrosis, sacro-iliac infection, synovitis secondary to juvenile idiopathic arthritis, ischio-pubic osteochondrosis, acetabular dysplasia, Klippel-Trenaunay syndrome and resolution of an eosinophilic granuloma. None of the children discharged following a normal scan has subsequently presented with hip disease. Conclusions. It is concluded that MRI is useful in the diagnosis of hip pain in children in whom routine investigation has not yielded an answer

Introduction: Despite clinical history, examination and plain radiography it is occasionally difficult to locate the origin of hip pain. This is particularly relevant where the management will be a total hip arthroplasty. Local anaesthetic arthrogram of the hip may provide a simple, safe and reliable test to determine if the hip is the source of the patient’s symptoms. The aim of this study was to establish the use of this investigation in the management of hip pain. Methods: All local anaesthetic hip arthrograms were reviewed from 1999 to 2005. All patients had completed a pain questionnaire following the arthrogram. Patients were classified into 3 groups; 1) Mild osteoarthritic changes on plain radiographs with possible referred pathology; 2) Minimal radiological changes but no obvious other pathology to refer pain; 3) Previous hip arthroplasty with unexplained pain. Those who subsequently had a primary or revision hip arthroplasty were assessed post-operatively by means of the Oxford hip score. Results: Fifty-seven patients in total underwent a local anaesthetic hip arthrogram. From all the groups 34 patients obtained pain relief and 24 proceeded to primary or revision hip arthroplasty. Twenty three (96%) had a satisfactory post-operative outcome at an average follow-up of 2 years (average Oxford score 28). The remaining 10 patients with positive arthrograms are still waiting for surgery. All negative arthrogram patients were successfully discharged. Discussion: A positive response to local anaesthetic hip arthrogram predicts a successful response to surgery. This permits accurate information of the results of hip surgery to be given to patients and aids in a management plan for a group of patients that can be otherwise challenging

Aims. Femoroacetabular impingement (FAI) patients report exacerbation of hip pain in deep flexion. However, the exact impingement location in deep flexion is unknown. The aim was to investigate impingement-free maximal flexion, impingement location, and if cam deformity causes hip impingement in flexion in FAI patients. Methods. A retrospective study involving 24 patients (37 hips) with FAI and femoral retroversion (femoral version (FV) < 5° per Murphy method) was performed. All patients were symptomatic (mean age 28 years (SD 9)) and had anterior hip/groin pain and a positive anterior impingement test. Cam- and pincer-type subgroups were analyzed. Patients were compared to an asymptomatic control group (26 hips). All patients underwent pelvic CT scans to generate personalized CT-based 3D models and validated software for patient-specific impingement simulation (equidistant method). Results. Mean impingement-free flexion of patients with mixed-type FAI (110° (SD 8°)) and patients with pincer-type FAI (112° (SD 8°)) was significantly (p < 0.001) lower compared to the control group (125° (SD 13°)). The frequency of extra-articular subspine impingement was significantly (p < 0.001) increased in patients with pincer-type FAI (57%) compared to cam-type FAI (22%) in 125° flexion. Bony impingement in maximal flexion was located anterior-inferior at femoral four and five o’clock position in patients with cam-type FAI (63% (10 of 16 hips) and 37% (6 of 10 hips)), and did not involve the cam deformity. The cam deformity did not cause impingement in maximal flexion. Conclusion. Femoral impingement in maximal flexion was located anterior-inferior distal to the cam deformity. This differs to previous studies, a finding which could be important for FAI patients in order to avoid exacerbation of hip pain in deep flexion (e.g. during squats) and for hip arthroscopy (hip-preservation surgery) for planning of bone resection. Hip impingement in flexion has implications for daily activities (e.g. putting on shoes), sports, and sex. Cite this article: Bone Joint Res 2023;12(1):22–32

Purpose: Anterior hip pain raises difficult diagnostic and therapeutic problems. Several diagnostic hypotheses are currently put forward to explain the origin of this pain: subcondral cysts, labrum problems and anterior bone impingement, an association of these mechanisms. We report our operative observations in thirteen cases and examined the findings in light of the clinical data and imaging results in order to search for aetiopathogenic factors leading to this type of pain and to elucidate possible therapeutic options. Material and methods: Thirteen video-assisted miniarthrotomy procedures were performed using a novel technique in patients presenting anterior hip pain. The preoperative work-up included physical examination, standard radiographs, and MRI and/or arthroscan to rule out an extraarticular cause and identify any lesion of the superomedial border of the hip joint (acetabular rim and/or labrum). Results: Physical examination was not greatly contributive excepting the two posttrauma cases. Four patients had unique lesions of the labrum with no associated bone lesions and no argument in favour of anterior bony impingement identifiable from the preoperative data. Regularisation of the labrum improved the pain in these four patients. Isolated chondroplasty of the femoral head in one patient was very partially improved. The eight other patients had lesions of the labrum associated with a femoral head imprint, bony defects or osteophytes at the head-neck junction, or actetabular defects, or an association of these three types of lesions. The patients raised major diagnostic problems because it was difficult to identify the initially causal mechanism: anterior mechanical conflict with a cam effect and secondary disinsertion of the labrum due to microtrauma (five of the patients had an insufficiently concave head-neck junction or an osteophyte which may have been the cause); or an initial lesion of the labrum causing secondary subchondral acetabular defects resulting from the disinsertion (this hypothesis was compatible with the presentation of three patients who had no femoral anomalies, notably absence of any defect and a normal head-neck junction). Discussion: Video-assisted mini-arthrotomy of the hip enables careful inspection of the entire hip joint and facilitates any therapeutic measures necessary. Isolated lesions of the labrum are exceptional and generally are associated with remodelling of the anterosuperior border of the acetabulum. The primary mechanism of a labrum lesion or an anterior cam effect is difficult to demonstrate in these patients who are often seen late in the process. Better knowledge of the aetiopathogenesis of anterior hip pain is needed to propose adapted and effective treatment

Aims. To evaluate how abnormal proximal femoral anatomy affects different femoral version measurements in young patients with hip pain. Methods. First, femoral version was measured in 50 hips of symptomatic consecutively selected patients with hip pain (mean age 20 years (SD 6), 60% (n = 25) females) on preoperative CT scans using different measurement methods: Lee et al, Reikerås et al, Tomczak et al, and Murphy et al. Neck-shaft angle (NSA) and α angle were measured on coronal and radial CT images. Second, CT scans from three patients with femoral retroversion, normal femoral version, and anteversion were used to create 3D femur models, which were manipulated to generate models with different NSAs and different cam lesions, resulting in eight models per patient. Femoral version measurements were repeated on manipulated femora. Results. Comparing the different measurement methods for femoral version resulted in a maximum mean difference of 18° (95% CI 16 to 20) between the most proximal (Lee et al) and most distal (Murphy et al) methods. Higher differences in proximal and distal femoral version measurement techniques were seen in femora with greater femoral version (r > 0.46; p < 0.001) and greater NSA (r > 0.37; p = 0.008) between all measurement methods. In the parametric 3D manipulation analysis, differences in femoral version increased 11° and 9° in patients with high and normal femoral version, respectively, with increasing NSA (110° to 150°). Conclusion. Measurement of femoral version angles differ depending on the method used to almost 20°, which is in the range of the aimed surgical correction in derotational femoral osteotomy and thus can be considered clinically relevant. Differences between proximal and distal measurement methods further increase by increasing femoral version and NSA. Measurement methods that take the entire proximal femur into account by using distal landmarks may produce more sensitive measurements of these differences. Cite this article: Bone Jt Open 2022;3(10):759–766

Aims. This study aimed to evaluate sagittal spinopelvic alignment (SSPA) in the early stage of rapidly destructive coxopathy (RDC) compared with hip osteoarthritis (HOA), and to identify risk factors of SSPA for destruction of the femoral head within 12 months after the disease onset. Methods. This study enrolled 34 RDC patients with joint space narrowing > 2 mm within 12 months after the onset of hip pain and 25 HOA patients showing femoral head destruction. Sharp angle was measured for acetabular coverage evaluation. Femoral head collapse ratio was calculated for assessment of the extent of femoral head collapse by RDC. The following parameters of SSPA were evaluated using the whole spinopelvic radiograph: pelvic tilt (PT), sacral slope (SS), pelvic incidence (PI), sagittal vertical axis (SVA), thoracic kyphosis angle (TK), lumbar lordosis angle (LL), and PI-LL. Results. The HOA group showed higher Sharp angles compared with the RDC group. PT and PI-LL were higher in the RDC group than the HOA group. SS and LL were lower in the RDC group than the HOA group. No difference was found in PI, SVA, or TK between the groups. Femoral head collapse ratio was associated with PT, SS, SVA, LL, and PI-LL. A PI-LL > 20° and a PT > 30° correlated with greater extent of femoral head destruction by RDC. From regression analysis, SS and SVA were significantly associated with the femoral head collapse ratio within 12 months after disease onset. Conclusion. Compared with HOA, RDC in the early stage correlated with sagittal spinopelvic malalignment. SS and SVA may partially contribute to the extent of femoral head destruction by RDC within 12 months after the onset of hip pain. The present study indicates a potential role of SSPA assessment in identification of RDC patients at risk for subsequent bone destruction. Cite this article: Bone Jt Open 2022;3(1):77–84

There are very few reports on apophysitis of the iliac crest although similar afflictions of the knee, heel, and elbow are well recognised conditions. Excesive forefoot pronation has been suggested as a contributory factor in the development of iliac apophysitis. We present our experience of this not so well known problem. Method: This is a prospective review of 8 patients (2- males, 6- females) between 12–16 years of age, who presented with pain in the hip of at least 3 months duration. They were prospectively reviewed over an average of 6 months (6–24 months). 7 of them were involved in some sort of sporting activity. 3 patients had to miss school due to pain. All of them had tenderness over the iliac crest, normal range of hip movements with pain on resisted hip abduction. None of them had any deformities in the lower limbs. Blood counts, ESR, CRP and radiographs were normal. 3 patients had persistent pain over 12 months hence had a bone scan which was normal. All patients had full symptomatic relief following rest, activity modification and anti-inflammatory medication. Conclusions: Unlike previous reports, our patients did not have characteristic radiographic changes thus the diagnosis of this condition seems to be mainly clinical. All pediatric patients with hip pain should be thoroughly investigated to rule out other sinister causes. None of our patients had any foot deformities questioning the hypothesis that iliac apophysitis develops secondary to excessive forefoot pronation. It is important to be aware of this condition, which causes considerable distress and can be relieved easily by conservative means

Aims. The lateral centre-edge angle (LCEA) is a plain radiological measure of superolateral cover of the femoral head. This study aims to establish the correlation between 2D radiological and 3D CT measurements of acetabular morphology, and to describe the relationship between LCEA and femoral head cover (FHC). Methods. This retrospective study included 353 periacetabular osteotomies (PAOs) performed between January 2014 and December 2017. Overall, 97 hips in 75 patients had 3D analysis by Clinical Graphics, giving measurements for LCEA, acetabular index (AI), and FHC. Roentgenographical LCEA, AI, posterior wall index (PWI), and anterior wall index (AWI) were measured from supine AP pelvis radiographs. The correlation between CT and roentgenographical measurements was calculated. Sequential multiple linear regression was performed to determine the relationship between roentgenographical measurements and CT FHC. Results. CT-measured LCEA and AI correlated strongly with roentgenographical LCEA (r = 0.92; p < 0.001) and AI (r = 0.83; p < 0.001). Radiological LCEA correlated very strongly with CT FHC (r = 0.92; p < 0.001). The sum of AWI and PWI also correlated strongly with CTFHC (r = 0.73; p < 0.001). CT measurements of LCEA and AI were 3.4° less and 2.3° greater than radiological LCEA and AI measures. There was a linear relation between radiological LCEA and CT FHC. The linear regression model statistically significantly predicted FHC from LCEA, F(1,96) = 545.1 (p < 0.001), adjusted R. 2. = 85.0%, with the prediction equation: CT FHC(%) = 42.1 + 0.77(XRLCEA). Conclusion. CT and roentgenographical measurement of acetabular parameters are comparable. Currently, a radiological LCEA greater than 25° is considered normal. This study demonstrates that those with hip pain and normal radiological acetabular parameters may still have deficiencies in FHC. More sophisticated imaging techniques such as 3D CT should be considered for those with hip pain to identify deficiencies in FHC. Cite this article: Bone Jt Open 2022;3(1):12–19

Aims. Pain is the most frequent complaint associated with osteonecrosis of the femoral head (ONFH), but the factors contributing to such pain are poorly understood. This study explored diverse demographic, clinical, radiological, psychological, and neurophysiological factors for their potential contribution to pain in patients with ONFH. Methods. This cross-sectional study was carried out according to the “STrengthening the Reporting of OBservational studies in Epidemiology” statement. Data on 19 variables were collected at a single timepoint from 250 patients with ONFH who were treated at our medical centre between July and December 2023 using validated instruments or, in the case of hip pain, a numerical rating scale. Factors associated with pain severity were identified using hierarchical multifactor linear regression. Results. Regression identified the following characteristics as independently associated with higher pain score, after adjustment for potential confounders: Association Research Circulation Osseous classification stage IIIa or IIIb, bone marrow oedema, grade 3 joint effusion, as well as higher scores on pain catastrophizing, anxiety, and central sensitization. The final model explained 69.7% of observed variance in pain scores, of which clinical and radiological factors explained 37%, while psychological and neurophysiological factors explained 24% and demographic factors explained 8.7%. Conclusion. Multidimensional characteristics jointly contribute to the severity of pain associated with ONFH. These findings highlight the need to comprehensively identify potential contributors to pain, and to personalize management and treatment accordingly. Cite this article: Bone Joint Res 2024;13(11):673–681

Abstract

Aims. The frequency of severe femoral retroversion is unclear in patients with femoroacetabular impingement (FAI). This study aimed to investigate mean femoral version (FV), the frequency of absolute femoral retroversion, and the combination of decreased FV and acetabular retroversion (AR) in symptomatic patients with FAI subtypes. Methods. A retrospective institutional review board-approved observational study was performed with 333 symptomatic patients (384 hips) with hip pain due to FAI evaluated for hip preservation surgery. Overall, 142 patients (165 hips) had cam-type FAI, while 118 patients (137 hips) had mixed-type FAI. The allocation to each subgroup was based on reference values calculated on anteroposterior radiographs. CT/MRI-based measurement of FV (Murphy method) and AV were retrospectively compared among five FAI subgroups. Frequency of decreased FV < 10°, severely decreased FV < 5°, and absolute femoral retroversion (FV < 0°) was analyzed. Results. A significantly (p < 0.001) lower mean FV was found in patients with cam-type FAI (15° (SD 10°)), and in patients with mixed-type FAI (17° (SD 11°)) compared to severe over-coverage (20° (SD 12°). Frequency of decreased FV < 10° was significantly (p < 0.001) higher in patients with cam-type FAI (28%, 46 hips) and in patients with over-coverage (29%, 11 hips) compared to severe over-coverage (12%, 5 hips). Absolute femoral retroversion (FV < 0°) was found in 13% (5 hips) of patients with over-coverage, 6% (10 hips) of patients with cam-type FAI, and 5% (7 hips) of patients with mixed-type FAI. The frequency of decreased FV< 10° combined with acetabular retroversion (AV < 10°) was 6% (8 hips) in patients with mixed-type FAI and 5% (20 hips) in all FAI patients. Of patients with over-coverage, 11% (4 hips) had decreased FV < 10° combined with acetabular retroversion (AV < 10°). Conclusion. Patients with cam-type FAI had a considerable proportion (28%) of decreased FV < 10° and 6% had absolute femoral retroversion (FV < 0°), even more for patients with pincer-type FAI due to over-coverage (29% and 13%). This could be important for patients evaluated for open hip preservation surgery or hip arthroscopy, and each patient requires careful personalized evaluation. Cite this article: Bone Jt Open 2022;3(7):557–565

Aims. The effect of pelvic tilt (PT) and sagittal balance in hips with pincer-type femoroacetabular impingement (FAI) with acetabular retroversion (AR) is controversial. It is unclear if patients with AR have a rotational abnormality of the iliac wing. Therefore, we asked: are parameters for sagittal balance, and is rotation of the iliac wing, different in patients with AR compared to a control group?; and is there a correlation between iliac rotation and acetabular version?. Methods. A retrospective, review board-approved, controlled study was performed including 120 hips in 86 consecutive patients with symptomatic FAI or hip dysplasia. Pelvic CT scans were reviewed to calculate parameters for sagittal balance (pelvic incidence (PI), PT, and sacral slope), anterior pelvic plane angle, pelvic inclination, and external rotation of the iliac wing and were compared to a control group (48 hips). The 120 hips were allocated to the following groups: AR (41 hips), hip dysplasia (47 hips) and cam FAI with normal acetabular morphology (32 hips). Subgroups of total AR (15 hips) and high acetabular anteversion (20 hips) were analyzed. Statistical analysis was performed using analysis of variance with Bonferroni correction. Results. PI and PT were significantly decreased comparing AR (PI 42° (SD 10°), PT 4° (SD 5°)) with dysplastic hips (PI 55° (SD 12°), PT 10° (SD 6°)) and with the control group (PI 51° (SD 9°) and PT 13° (SD 7°)) (p < 0.001). External rotation of the iliac wing was significantly increased comparing AR (29° (SD 4°)) with dysplastic hips (20°(SD 5°)) and with the control group (25° (SD 5°)) (p < 0.001). Correlation between external rotation of the iliac wing and acetabular version was significant and strong (r = 0.81; p < 0.001). Correlation between PT and acetabular version was significant and moderate (r = 0.58; p < 0.001). Conclusion. These findings could contribute to a better understanding of hip pain in a sitting position and extra-articular subspine FAI of patients with AR. These patients have increased iliac external rotation, a rotational abnormality of the iliac wing. This has implications for surgical therapy with hip arthroscopy and acetabular rim trimming or anteverting periacetabular osteotomy (PAO). Cite this article: Bone Jt Open 2021;2(10):813–824

To identify the differences in inflammatory profiles between hip OA, knee OA and non-OA control cohorts and investigate the association between cytokine expression and clinical outcome measurements, specifically pain.

A total of 250 individuals were recruited in three cohorts (100 knee OA, 50 hip OA, 100 control). Serum was collected and inflammatory profiles analysed using the Multiplex Human Cytokine Panel (Millipore) on the Luminex 100 platform (Luminex Corp., Austin, TX). The pain, physical function and activity limitations of hip OA cohort were scored using the WOMAC, SF-36, HHS and UCLA scores. All cytokine levels were compared between cohorts individually using Mann–Whitney–Wilcoxon (MWW) test with Bonferroni multiple comparison correction. Within hip OA cohorts, the effect of hip alignment (impingement and dysplasia) and radiographic grade (Kellgren and Lawrence grade, K/L grade) on cytokine levels were accessed by MWW test. Spearman's rank correlation test used to assess the association between cytokines and pain levels.

The three cohorts showed distinct inflammatory profiles. Specifically, EGF, FGF-2, MCP-3, MIP-1a, IL-8 were significant different between knee and hip OA; FGF-2, GRO, IL-8, MCP-1, VEGF were significant different between hip OA and control; Eotaxin, GRO, MCP-1, MIP-1b, VEGF were significant different between knee OA and control (p-value < 0.0012). For hip OA cohorts, cytokines do not differ between K/L grade three and K/L grade four or between patients that displayed either impingement or dysplasia. Three cytokines were significant associated with pain: IL-6 (p-value = 0.045), MDC (p-value = 0.032) and IP-10 (p-value = 0.038).

We have demonstrated that differences in serum inflammatory profiles exist between hip and knee OA patients. These differences suggest that OA may include different inflammatory subtypes according to affected joints. We also identified that the cytokine IL-6, MDC and IP-10 are associated with pain level in hip OA patients. These cytokines might help explain the inconsistent of presentation of pain with radiographical severity of OA joints. Future studies are needed to validate our findings and then to understand the following questions: (1) how differently affected joints are reflected in systematic biomarkers; (2) how these cytokines are biologically involved in the OA pain pathway.

Introduction

It is not uncommon to encounter patients with atypical hip or lower extremity pain, ill-defined clinico-radiological features and concomitant hip and lumbar spine arthritis. It has been hypothesized that an anaesthetic hip arthrogram can help identify the source of pain in these cases. The purpose of this study is to analyze our experience with this technique in order to verify its accuracy.

Over half of postpartum women experience pelvic ring or hip pain, with multiple anatomic locations involved. The sacroiliac joints, pubic symphysis, lumbar spine and pelvic girdle are all well documented pain generators. However, despite the prevalence of postpartum hip pain, there is a paucity of literature regarding underlying soft tissue intra-articular etiologies. The purpose of this systematic review is to document and assess the available evidence regarding underlying intra-articular soft tissue etiologies of peri- and postpartum hip pain. Three online databases (Embase, PubMed and Ovid [MEDLINE]) were searched from database inception until April 11, 2021. The inclusion criteria were English language studies, human studies, and those regarding symptomatic labral pathology in the peri- or postpartum period. Exclusion criteria were animal studies, commentaries, book chapters, review articles and technical studies. All titles, relevant abstracts and full-text articles were screened by two reviewers independently. Descriptive characteristics including the study design, sample size, sex ratio, mean age, clinical and radiographic findings, pathology, subsequent management and outcomes were documented. The methodological quality of the included studies was assessed using the Methodological Index for Non-Randomized Studies (MINORS) instrument. The initial search identified 2472 studies. A systemic screening and assessment of eligibility identified 5 articles that satisfied the inclusion criteria. Twenty-two females were included. Twenty patients presented with labral pathology that necessitated hip arthroscopy with labral debridement or repair with or without acetabuloplasty and/or femoroplasty. One patient presented with an incidental labral tear in the context of osteitis condensans illi. One patient presented with post-traumatic osteoarthritis necessitating a hip replacement. The mean MINORS score of these 5 non-comparative studies was 2.8 (range 0-7) demonstrating a very low quality of evidence. The contribution of intra-articular soft tissue injury is a documented, albeit sparse, etiology contributing to peri- and postpartum hip pain. Further research to better delineate the prevalence, mechanism of injury, natural history and management options for women suffering from these pathologies at an already challenging time is necessary to advance the care of these patients

There is some evidence to suggest that outcomes of THA in patients with minimal radiographic osteoarthritis may not be associated with predictable outcomes. The aim of this study was to:. Assess the outcome of patients with hip pain who underwent THA with no or minimal radiographic signs of osteoarthritis,. Identify patient comorbidities and multiplanar imaging findings which are predictive of outcome,. Compare the outcome in these patients to the expected outcome of THA in hip OA. A retrospective review of 107 hips (102 patients, 90F:12M, median age 40.6, IQR 35.1–45.8 years, range 18–73) were included for analysis. Plain radiographs were evaluated using the Tonnis grading scale of hip OA. Outcome measures were all-cause revision; iHOT12; EQ-5D; Oxford Hip Score; UCLA Activity Scale; and whether THA had resulted in the patient's hip pain and function being Better/Same/Worse. The median Oxford Hip Score was 33.3 (IQR 13.9, range 13–48), and 36/107 (33.6%) hips achieved an OHS≥42. There was no association between primary hip diagnosis and post-operative PROMs. A total of 91 of the 102 patients (89.2%, 93 hips) reported that their hip pain and function was Better than prior to THA and would have the surgery again, 7 patients (6.8%, 10 hips) felt the Same, and 4 patients (3.9%, 4 hips) felt Worse and would not have the surgery again. Younger patients undergoing total hip arthroplasty with no or minimal radiographic osteoarthritis had lower postoperative Oxford Hip Scores than the general population; though most felt symptomatically better and knowing what they know now, would have surgery again. Those with chronic pain syndrome or hypermobility were likely to benefit less. Those with subchondral cysts or joint space narrowing on CT imaging were more likely to achieve higher functional scores and satisfaction