Introduction. Subtle deformities of the acetabulum and proximal femur are recognised as biomechanical risk factors for the development of hip osteoarthritis (OA) as well as a cause of hip and groin pain. We undertook this study to examine relationships between a number of morphological measurements of the acetabulum and proximal femur and the hip pain in a 20-year longitudinal study. Methods. In 1989 women of 45–64 years of age were recruited. Each had an AP-Pelvis radiograph at Year-2. These radiographs were analysed using a validated programme for measuring morphology. All morphological measurements were read blinded to outcome. At year 3 all participants were asked whether they experienced hip pain (side specific). This was repeated at visits up to and including 20-years. Logistic regression analysis (with robust standard errors and clustering by subject identifier) was performed using hip pain as a binary outcome. The model adjusted for baseline age, BMI and joint space and included only participants who were pain free on initial questioning. Results. 743 participants were included in the analysis. Median age 74.0. Pain was reported in 14.2% of hips. Logistic regression analyses revealed that extrusion index and LCE were significantly associated with hip pain before and after adjusting for covariates (OR 4.88[95%CI 1.32–17.97, p=0.017] and 0.84[95%CI 0.74–0.96, p=0.012] respectively). Modified triangular index height (MTIH) was also significantly associated after adjusting for covariates (OR 1.10[95%CI 1.01–1.20, p=0.022]). Extrusion index and MTIH were independently associated with hip pain at 20-years when used in the same model. No significant interaction was identified. Conclusions. This study provides evidence that measurements of hip morphology characteristic of previously undiagnosed dysplasia and FAI are predictive of hip pain in a 20-year longitudinal study. MTIH, LCE and Extrusion index were significant predictors of pain. This is the first study to describe these associations between hip morphology and pain in a longitudinal cohort

Recently, femoroacetabular impingement has been recognised as a cause of early osteoarthritis. There are two mechanisms of impingement: 1) cam impingement caused by a non-spherical head and 2) pincer impingement caused by excessive acetabular cover. We hypothesised that both mechanisms result in different patterns of articular damage. Of 302 analysed hips only 26 had an isolated cam and 16 an isolated pincer impingement. Cam impingement caused damage to the anterosuperior acetabular cartilage with separation between the labrum and cartilage. During flexion, the cartilage was sheared off the bone by the non-spherical femoral head while the labrum remained untouched. In pincer impingement, the cartilage damage was located circumferentially and included only a narrow strip. During movement the labrum is crushed between the acetabular rim and the femoral neck causing degeneration and ossification.

Both cam and pincer impingement lead to osteoarthritis of the hip. Labral damage indicates ongoing impingement and rarely occurs alone.

Femoroacetabular impingement recently was recognized as cause for osteoarthritis of the hip. There are two mechanism of impingement: (1) cam impingement caused by a non-spherical head, and (2) pincer impingement due to acetabular overcover. We hypothesized that both mechanism result in different articular damage patterns. Of 302 analyzed hips only 26 had an isolated cam and 16 an isolated pincer impingement. Cam impingement caused anterosuperior acetabular cartilage damage with a separation between labrum and cartilage. During flexion the cartilage is sheared off the bone by the non-spherical part of the femoral head. In pincer impingement the cartilage damage was located circumferentially, invovolving only a narrow strip along the acetabular rim. During motion the labrum is crushed between the acetabular rim and the femoral neck causing degeneration and ossification of the labrum.

Cam and pincer impingement are two basic mechanism that lead to osteoarthrosis of the hip. The articular damage pattern differs substantially. Isolated cam or pincer impingement is rare, in most hips a combination is present. Labral damage indicates ongoing impingement and rarely occurs alone.

Aims

Femoroacetabular impingement (FAI) has been highlighted and well documented primarily in Western countries and there are few large studies focused on FAI-related morphological assessment in Asian patients. We chose to investigate this subject.

Introduction: Subtle deformity of the hip joint may cause osteoarthritis. In femoroacetabular impingement (FAI), cam deformities damage acetabular cartilage. Whether surgical removal of cam lesions halts progression is unknown. Sensitive, non-invasive assays of chondral damage are required to evaluate early treatment efficacy.

Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) permits inference of glycosaminoglycan (GAG) distribution. We aimed to determine whether hips with cam deformities have altered GAG content, using dGEMRIC.

Methods: Subjects were recruited from a prospective cohort study. All were clinically and radiographically assessed. Hips with a normal joint space width (> 2.5mm) were eligible for dGEMRIC. 32 Hips (18 male, 14 female, mean age 51.7 years, none of whom had been investigated for hip pain) with (n=21) and without (n=11) cam deformities were scanned.

2 regions of interest (ROI) were studied:

acetabular cartilage from 12 to 3 O’Clock (T1-Index-acet).

The average of all pixels within the given ROI defined the T1-index.

For each hip, the ratio of the GAG content T1-Index-acet/T1-Indextotal was calculated. Mean T1-Indexto-tal and T1-Indexacet/T1-Indextotal were compared.

Results: T1-Indextotal were similar (689ms v 700ms, p=0.79) but T1-Indexacet/T1-Indextotal was lower in cam hips (0.93 v 1.01, p=0.017), indicating localised depletion of GAG content. Cam hips with positive clinical signs had lower T1-Indextotal than cam hips without (629ms v 717ms, p=0.055), and non-cam hips (629ms v 722ms, p=0.049).

Discussion: Cam hips have lower GAG content of their anterosuperior acetabular cartilage. dGEMRIC identified more generalised disease in cases with positive clinical findings. Ratios of GAG content for specific ROIs enable mapping of chondral damage. This may aid understanding of early disease mechanisms, track progression, and facilitate assessment of the efficacy of surgical procedures.

Abstract. Background. Femoroacetabular impingement (FAI) has been extensively investigated and is strongly associated with athletic participation. The aim of this systematic review is to assess: the prevalence of cam-type FAI across various sports, whether kinematic variation between sports influences hip morphology, and whether performance level, duration and frequency of participation or other factors influence hip morphology in a sporting population. Methods. A systematic search of Embase, PubMed and the Cochrane Library was undertaken following PRISMA guidelines. The study was registered on the PROSPERO database (CRD4202018001). Prospective and retrospective case series, case reports and review articles published after 1999 were screened and those which met the inclusion criteria decided a priori were included for analysis. Results. The literature search identified 58 relevant articles involving 5,683 participants. Forty-nine articles described a higher prevalence of FAI across various ‘hip-heavy’ sports, including soccer, basketball, baseball, ice hockey, skiing, golf and ballet. In studies including non-athlete controls, a greater prevalence of FAI was reported in 66.7% of studies (n=8/12). The highest alpha angle was identified at the 1 o'clock position (n=9/9) in football, skiing, golf, ice hockey and basketball. Maximal alpha angle was found to be located in a more lateral position in goalkeepers versus positional players in ice hockey (1 o'clock vs 1.45 o'clock). A positive correlation was also identified between the alpha angle and both age and activity level (n=5/8 and n=2/3, respectively) and also between prevalence of FAI and both age and activity level (n=2/2 and n=4/5), respectively. Conclusions. Hip-heavy sports show an increased prevalence of FAI, with specific sporting activities influencing hip morphology. Both a longer duration and increased level of training also resulted in an increased prevalence of FAI

Executing an extended retinacular flap containing the blood supply for the femoral head, reduction osteotomy (FHO) can be performed, increasing the potential of correction of complex hip morphologies. The aim of this study was to analyse the safety of the procedure and report the clinical and radiographic results in skeletally mature patients with a minimum follow up of two years. Twelve symptomatic patients (12 hips) with a mean age of 17 years underwent FHO using surgical hip dislocation and an extended soft tissue flap. Radiographs and magnetic resonance imaging producing radial cuts (MRI) were obtained before surgery and radiographs after surgery to evaluate articular congruency, cartilage damage and morphologic parameters. Clinical functional evaluation was done using the Non-Arthritic Hip Score (NAHS), the Hip Outcome Score (HOS), and the modified Harris Hip Score (mHHS). After surgery, at the latest follow-up no symptomatic avascular necrosis was observed and all osteotomies healed without complications. Femoral head size index improved from 120 ± 10% to 100 ± 10% (p<0,05). Femoral head sphericity index improved from 71 ± 10% before surgery to 91 ± 7% after surgery (p<0,05). Femoral head extrusion index improved from 37 ± 17% to 5 ± 6% (p< 0,05). Twenty five percent of patients had an intact Shenton line before surgery. After surgery this percentage was 75% (p<0,05). The NAHS score improved from a mean of 41 ± 18 to 69 ± 9 points after surgery (p< 0,05). The HOS score improve from 56 ± 24 to 83 ± 17 points after surgery (p< 0,05) and the mHHS score improved from 46 ± 15 before surgery to 76 ± 13 points after surgery (p< 0,05). In this series, femoral head osteotomy could be considered as safe procedure with considerable potential to correct hip deformities and improve patients reported outcome measures (PROMS). Level of evidence - Level IV, therapeutic study. Keywords - Femoral head osteotomy, Perthes disease, acetabular dysplasia, coxa plana

Aims. It has been well documented in the arthroplasty literature that lumbar degenerative disc disease (DDD) contributes to abnormal spinopelvic motion. However, the relationship between the severity or pattern of hip osteoarthritis (OA) as measured on an anteroposterior (AP) pelvic view and spinopelvic biomechanics has not been well investigated. Therefore, the aim of the study is to examine the association between the severity and pattern of hip OA and spinopelvic motion. Methods. A retrospective chart review was conducted to identify patients undergoing primary total hip arthroplasty (THA). Plain AP pelvic radiographs were reviewed to document the morphological characteristic of osteoarthritic hips. Lateral spine-pelvis-hip sitting and standing plain radiographs were used to measure sacral slope (SS) and pelvic femoral angle (PFA) in each position. Lumbar disc spaces were measured to determine the presence of DDD. The difference between sitting and standing SS and PFA were calculated to quantify spinopelvic motion (ΔSS) and hip motion (ΔPFA), respectively. Univariate analysis and Pearson correlation were used to identify morphological hip characteristics associated with changes in spinopelvic motion. Results. In total, 139 patients were included. Increased spinopelvic motion was observed in patients with loss of femoral head contour, cam deformity, and acetabular bone loss (all p < 0.05). Loss of hip motion was observed in patients with loss of femoral head contour, cam deformity, and acetabular bone loss (all p < 0.001). A decreased joint space was associated with a decreased ΔPFA (p = 0.040). The presence of disc space narrowing, disc space narrowing > two levels, and disc narrowing involving the L5–S1 segment were associated with decreased spinopelvic motion (all p < 0.05). Conclusion. Preoperative hip OA as assessed on an AP pelvic radiograph predicts spinopelvic motion. These data suggest that specific hip osteoarthritic morphological characteristics listed above alter spinopelvic motion to a greater extent than others. Cite this article: Bone Joint J 2023;105-B(5):496–503

Aims. This paper aims to review the evidence for patient-related factors associated with less favourable outcomes following hip arthroscopy. Methods. Literature reporting on preoperative patient-related risk factors and outcomes following hip arthroscopy were systematically identified from a computer-assisted literature search of Pubmed (Medline), Embase, and Cochrane Library using Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines and a scoping review. Results. Assessment of these texts yielded 101 final articles involving 90,315 hips for qualitative analysis. The most frequently reported risk factor related to a less favourable outcome after hip arthroscopy was older age and preoperative osteoarthritis of the hip. This was followed by female sex and patients who have low preoperative clinical scores, severe hip dysplasia, altered hip morphology (excess acetabular retroversion or excess femoral anteversion or retroversion), or a large cam deformity. Patients receiving workers’ compensation or with rheumatoid arthritis were also more likely to have a less favourable outcome after hip arthroscopy. There is evidence that obesity, smoking, drinking alcohol, and a history of mental illness may be associated with marginally less favourable outcomes after hip arthroscopy. Athletes (except for ice hockey players) enjoy a more rapid recovery after hip arthroscopy than non-athletes. Finally, patients who have a favourable response to local anaesthetic are more likely to have a favourable outcome after hip arthroscopy. Conclusion. Certain patient-related risk factors are associated with less favourable outcomes following hip arthroscopy. Understanding these risk factors will allow the appropriate surgical indications for hip arthroscopy to be further refined and help patients to comprehend their individual risk profile. Cite this article: Bone Joint J 2020;102-B(7):822–831

Aims. To determine if patient ethnicity among patients with a hip fracture influences the type of fracture, surgical care, and outcome. Methods. This was an observational cohort study using a linked dataset combining data from the National Hip Fracture Database and Hospital Episode Statistics in England and Wales. Patients’ odds of dying at one year were modelled using logistic regression with adjustment for ethnicity and clinically relevant covariates. Results. A total of 563,640 patients were included between 1 April 2011 and 1 October 2020. Of these, 476,469 (85%) had a coded ethnicity for analysis. Non-white patients tended to be younger (mean 81.2 vs 83.0 years), and were more commonly male (34.9% vs 28.5%; p < 0.001). They were less likely to be admitted from institutional care (12.9% vs 21.8%; p < 0.001), to have normal cognition (53.3% vs 62.0%; p < 0.001), and to be free of comorbidities (22.0% vs 26.8%; p < 0.001), but were more likely to be from the most deprived areas (29.4% vs 17.3%; p < 0.001). Non-white patients were more likely to experience delay to surgery for medical reasons (14.8% vs 12.7%; p < 0.001), more likely to be treated with an intramedullary nail or a sliding hip screw (52.5% vs 45.1%; p < 0.001), and less likely to be mobilized by the day after surgery (74.3% vs 79.0%; p < 0.001). Mortality was higher among non-white inpatients (9.2% vs 8.4% for white), but was lower at one year after hip fracture (26.6% vs 30.3%). Conclusion. Our study identified serious problems with the quality of NHS ethnicity data. Despite this, we have shown that there is complex variation in case-mix and hip fracture morphology between ethnic groups. We have also identified variations in care received between ethnic groups, and that disparities in healthcare may contribute to poorer outcome. Inpatient mortality is higher in non-white patients, although this finding reverses after discharge, and one-year mortality is lower. Patients from ethnic minority backgrounds experience disparities in healthcare, however at one year postoperatively non-white patients have a statistically significant lower mortality after controlling for relevant clinical covariates. Cite this article: Bone Joint J 2024;106-B(10):1182–1189

Clinical graphics allows creation of three dimensional simulation based on CT or MRI that allows pre-operative planning. The software reports several hip morphological parameters routinely. Our aim was to validate the measurements of acetabular morphological parameters using CT based clinical graphics in patients presenting with symptomatic hip pain. We reviewed standardised plain radiographs, CT scans and 3D clinical graphics outputs of 42 consecutive hips in 40 patients presenting with symptomatic hip pain. Acetabular index (AI), lateral centre edge angle (LCE), acetabular and femoral version measurements were analysed for the 3D clinical graphics with radiographs and CT as gold standard. Significant differences were noted in measurements of AI, LCE, acetabular version and femoral version using the 3D motion analysis versus conventional measures, with only acetabular version showing comparable measurements. Correlation between 3D clinical graphics and conventional measures of acetabular morphology (AI, LCE) showed only slight agreement (ICC <0.4); while substantial agreement was noted for acetabular and femoral version (IC > 0.5). Acetabular morphological parameters measured by 3D clinical graphics are not reliable or validated. While clinicians may pursue the use of 3D clinical graphics for preoperative non-invasive planning, caution should be exercised when interpreting the reports of hip morphological parameters such as AI and LCE

Background. Cam morphology develops during adolescence and predisposes individuals to future hip pain and osteoarthritis. An improved understanding of cam development is required to determine whether the process is modifiable. Hypothesis/Purpose. The aim of this study was to characterise the risk factors, timing, and pathogenesis of cam formation. Study Design. Longitudinal prospective observational cohort study. Methods. Longitudinal observational cohort study over three years of individuals from football club academies and an age-matched control population, aged 9–18 years at baseline. Assessments include questionnaires, clinical examination, and MRI of both hips. Alpha angle and epiphyseal extension were measured on radial images. Results. Cohort comprised male academy footballers (121 at baseline and 78 at follow-up) and male and female controls (107 at baseline and 71 at follow-up). Mean change in cartilage alpha angle was 12.4° (SD 8.4) for footballers, 7.3° (SD 6.0) for male controls and 4.0° (SD 4.1) for female controls. A positive correlation was found between Physical Activity Questionnaire Score and change in cartilage alpha angle (coefficient 0.787, p=<0.001). The greatest change in cartilage alpha angle occurred in individuals aged 11–12 years at baseline, with no significant change after 14 years of age. A positive correlation between mean cartilage alpha angle and lateral epiphyseal extension was observed (r. 2. = 0.294, p=0.029). Conclusions. Males undertaking intense sporting activity during adolescence at greatest risk of developing cam morphology, but there is no significant change in hip morphology after 14 years of age. The findings are consistent with physiological adaptation and epiphyseal extension in response to hip loading during skeletal immaturity

Aims. The aims of this study were to review the surgical technique for a combined femoral head reduction osteotomy (FHRO) and periacetabular osteotomy (PAO), and to report the short-term clinical and radiological results of a combined FHRO/PAO for the treatment of selected severe femoral head deformities. Patients and Methods. Between 2011 and 2016, six female patients were treated with a combined FHRO and PAO. The mean patient age was 13.6 years (12.6 to 15.7). Clinical data, including patient demographics and patient-reported outcome scores, were collected prospectively. Radiologicalally, hip morphology was assessed evaluating the Tönnis angle, the lateral centre to edge angle, the medial offset distance, the extrusion index, and the alpha angle. Results. The mean follow-up was 3.3 years (2 to 4.6). The modified Harris Hip Score improved by 33.0 points from 53.5 preoperatively to 83.4 postoperatively (p = 0.03). The Western Ontario McMasters University Osteoarthritic Index score improved by 30 points from 62 preoperatively to 90 postoperatively (p = 0.029). All radiological parameters showed significant improvement. There were no long-term disabilities and none of the hips required early conversion to total hip arthroplasty. Conclusion. FHRO combined with a PAO resulted in clinical and radiological improvement at short-term follow-up, suggesting it may serve as an appropriate salvage treatment option for selected young patients with severe symptomatic hip deformities

Traumatic hip dislocation is a rare injury in orthopaedic practice and typically occures in high energy trauma. The goal of this study was to analyze hip morphology in patients with low energy traumatic hip dislocations and to compare it with a control group. We performed a retrospective comparative study. The study group included 45 patients with 45 traumatic posterior hip dislocation. Inclusion criteria were traumatic hip dislocation with simple acetabular rim or Pipkin I or II fracture. Traumatic dislocations combined with other acetabular or femoral fractures were excluded. The control group consisted of 90 patients (180 hips) that underwent radiographic examination for urogenital indication and had no history of hip pain. Hip morphology was assessed on antero-posterior and axial views. The study group showed significantly increased incidence (p<0.001) of positive cross-over sign (82% vs. 27%) with a increased retroversion index (26 ± 17 [0–56] vs. 6 ± 12 [0–53]), positive ischial spine sign (70% vs. 34%), and positive posterior wall sign (79% vs. 21). Hips that underwent an low energy posterior traumatic hip dislocation show significanly more radiographic signs for acetabular retroversion compared to a control group. Therefore, acetabular retroversion seems to be a contributing factor for posterior traumatic hip dislocation

An increased prevalence of osteoarthritis (OA) in post-menopausal women has led to the suggestion that hormonal factors may play a role in the pathogenesis. This study aims to examine if undergoing a hysterectomy, both with retention and removal of ovaries, predisposes women to OA and secondly if the development is influenced by hormone replacement therapy (HRT). Statistical shape modelling (SSM) is a method of image analysis allowing for detection of subtle shape variation described by landmark points. Through the generation of linearly independent modes of variation, each image can be described in terms of numerical scores. 149 radiographs from female participants of the Osteoarthritis Initiative (OAI) were examined to compare hip morphology in those who had undergone hysterectomies compared to controls. No differences were observed in BMI, age, height or weight between groups. ANOVA and Games-Howell post-hoc analysis showed that modes 3 and 5 were statistically significant. Lower mode 3 scores were associated with hysterectomy (p=0.019), with narrowing of the femoral neck and increased acetabular coverage. Lower mode 5 scores were associated with hysterectomy and oophorectomy (p=0.049), displaying reduced coverage of the femoral head, superolateral migration of the femoral head and larger greater trochanter. No associations were observed between HRT use and OA. The subtle morphologic features of hip OA present in only hysterectomised women suggests undergoing a hysterectomy may be a predisposing factor and a clinical consideration. The use of HRT was not observed to influence the development of OA and thus cannot be suggested as a protective measure

We examined the morphology of mammalian hips asking whether evolution can explain the morphology of impingement in human hips. We describe two stereotypical mammalian hips, coxa recta and coxa rotunda. Coxa recta is characterised by a straight or aspherical section on the femoral head or head-neck junction. It is a sturdy hip seen mostly in runners and jumpers. Coxa rotunda has a round femoral head with ample head-neck offset, and is seen mostly in climbers and swimmers. Hominid evolution offers an explanation for the variants in hip morphology associated with impingement. The evolutionary conflict between upright gait and the birth of a large-brained fetus is expressed in the female pelvis and hip, and can explain pincer impingement in a coxa profunda. In the male hip, evolution can explain cam impingement in coxa recta as an adaptation for running

Pelvic obliquity is a common finding in adolescents with cerebral palsy, however, there is little agreement on its measurement or relationship with hip development at different gross motor function classification system (GMFCS) levels. . The purpose of this investigation was to study these issues in a large, population-based cohort of adolescents with cerebral palsy at transition into adult services. . The cohort were a subset of a three year birth cohort (n = 98, 65M: 33F, with a mean age of 18.8 years (14.8 to 23.63) at their last radiological review) with the common features of a migration percentage greater than 30% and a history of adductor release surgery. . Different radiological methods of measuring pelvic obliquity were investigated in 40 patients and the angle between the acetabular tear drops (ITDL) and the horizontal reference frame of the radiograph was found to be reliable, with good face validity. This was selected for further study in all 98 patients. . The median pelvic obliquity was 4° (interquartile range 2° to 8°). There was a strong correlation between hip morphology and the presence of pelvic obliquity (effect of ITDL on Sharpe’s angle in the higher hip; rho 7.20 (5% confidence interval 5.59 to 8.81, p < 0.001). This was particularly true in non-ambulant adolescents (GMFCS IV and V) with severe pelvic obliquity, but was also easily detectable and clinically relevant in ambulant adolescents with mild pelvic obliquity. . The identification of pelvic obliquity and its management deserves closer scrutiny in children and adolescents with cerebral palsy. Cite this article: Bone Joint J 2015;97-B:1435–40

We have tested the reliability of a recently reported classification system of hip morphology in adolescents with cerebral palsy in whom the triradiate cartilage was closed. The classification is a six-grade ordinal scale, based on the measurement of the migration percentage and an assessment of Shenton’s arch, deformity of the femoral head, acetabular deformity and pelvic obliquity. Four paediatric orthopaedic surgeons and four physiotherapists received training in the use of the classification which they applied to the assessment of 42 hip radiographs, read on two separate occasions. The inter- and intra-observer reliability was assessed using the intraclass correlation coefficient and found to be excellent, with it ranging from 0.88 to 0.94. The classification in our study was shown to be valid (based on migration percentage), and reliable. As a result we believe that it can now be used in studies describing the natural history of hip displacement in cerebral palsy, in outcome studies and in communication between clinicians

The December 2013 Children’s orthopaedics Roundup. 360. looks at: Long term-changes in hip morphology following osteotomy; Arthrogrypotic wrist contractures are surgically amenable; Paediatric femoral lengthening over a nail; Current management of paediatric supracondylar fractures; MRI perfusion index predictive of Perthes’ progression; Abduction bracing effective in residual acetabular deformity; Hurler syndrome in the spotlight; and the Pavlik works for femoral fractures too!