The Rise and Fall of the Hip: From Skeletal Development to Osteoarthritis

__Abstract__ Osteoarthritis is a common disease and accounts for a detrimental impact on the quality of life. The etiology of the disease is largely unknown and hence its treatment is limited to pain management until the patient can undergo total joint replacement. In this thesis, we first investigated the role of hip morphology in the development of hip osteoarthritis. It was found that a cam deformity (a non-spherical femoral head due to extra bone formation) is highly associated with development of hip osteoarthritis. We further provided a definition for the presence of a cam deformity. Finally, we investigated if and how a cam deformity develops during skeletal maturation. A cam deformity develops gradually and only during adolescence in between the age of around 13 to 17 years. Its development is a result of high impact sports practice during skeletal growth. In conclusion, in this thesis we found a relatively new risk factor for the development of osteoarthritis (cam deformity). Interestingly, the development of a cam deformity can possibly be prevented during skeletal maturation by adjusting the loads applied to the hip, which might substantially decrease the future prevalence of hip osteoarthritis

Prevalence and radiological definitions of acetabular dysplasia after the age of 2 years:a systematic review

Acetabular dysplasia is one of the most common causes of early hip osteoarthritis and hip replacement surgery. Recent literature suggests that acetabular dysplasia does not always originate at infancy, but can also develop later during childhood. This systematic review aims to appraise the literature on prevalence numbers of acetabular dysplasia in children after the age of 2 years. A systematic search was performed in several scientific databases. Publications were considered eligible for inclusion if they presented prevalence numbers on acetabular dysplasia in a general population of healthy children aged 2–18 years with description of the radiological examination. Quality assessment was done using the Newcastle-Ottawa score. Acetabular dysplasia was defined mild when: the center-edge angle of Wiberg (CEA-W) measured 15–20°, the CEA-W ranged between -1 to -2SD for age, or based on the acetabular index using thresholds from the Tönnis table. Severe dysplasia was defined by a CEA-W < 15°, <-2SD for age, or acetabular index according to Tönnis. Of the 1837 screened articles, four were included for review. Depending on radiological measurement, age and reference values used, prevalence numbers for mild acetabular dysplasia vary from 13.4 to 25.6% and for severe acetabular dysplasia from 2.2 to 10.9%. Limited literature is available on prevalence of acetabular dysplasia in children after the age of 2 years. Prevalence numbers suggest that acetabular dysplasia is not only a condition in infants but also highly prevalent later in childhood

The prevalence of cam and pincer morphology and its association with development of hip osteoarthritis

Our understanding of femoroacetabular impingement syndrome is slowly improving. The number of studies on all aspects (etiology, prevalence, pathophysiology, natural history, treatment, and preventive measures) of femoroacetabular impingement syndrome has grown exponentially over the past few years. This commentary provides the latest updates on the prevalence of cam and pincer hip morphology and its relationship with development of hip osteoarthritis (OA). Cam and pincer morphology is highly prevalent in the general population and in this paper is presented for different subgroups based on age, sex, ethnicity, and athletic activity. Methodological issues in determining prevalence of abnormal hip morphology are also discussed. Cam morphology has been associated with development of hip OA, but the association between pincer morphology and hip OA is much less clear. Results from reviewed studies, as well as remaining gaps in literature on this topic, are critically discussed and put into perspective for the clinician

Radiographic assessment of the pubic symphysis in elite male adolescent football players:Development and reliability of the Maturing Adolescent Pubic Symphysis (MAPS) classification

Introduction: The pubic symphysis is susceptible to growth related injuries long after the adolescent growth spurt. Our study describes the radiographic maturation of the pubic symphysis on pelvic radiographs in adolescent football players and introduces the Maturing Adolescent Pubic Symphysis classification (MAPS classification). Methods: Anteroposterior pelvic radiographs of 105 healthy adolescent male football players between 12 and 24 years old were used to develop the classification system. The radiological scoring of the symphyseal joint was developed over five rounds. The final MAPS classification items were scored in random order by two experienced readers, blinded to the age of the participant and to each other's scoring. The inter- and intra-rater reliability were examined using weighted kappa (κ). Results: We developed a classification system with descriptive definitions and an accompanying pictorial atlas. The symphyseal joint was divided into three regions: the superior corners, and the upper and lower regions of the joint line. Inter-rater reliability was substantial to almost perfect: superior region: κ = 0.70 (95% CI 0.60–––0.79), upper region of the joint line: κ = 0.89 (95% CI 0.86–––0.92), lower region of the joint line: κ = 0.65 (95% CI 0.55–––0.75). The intra-observer reliability showed similar results. Conclusion: The Maturing Adolescent Pubic Symphysis classification (MAPS classification) is a reliable descriptive classification of the radiographic maturation of the pubic symphysis joint in athletic males. The stages can provide a basis for understanding in clinical practice and will allow future research in this field.</p

Which factors differentiate athletes with hip/groin pain from those without? A systematic review with meta-analysis

Background: Hip and groin injuries are common in many sports. Understanding the factors differentiating athletes with hip/groin pain from those without these injuries could facilitate management and prevention. Objective: Conduct a systematic review and meta-analysis of the literature on factors differentiating athletes with and without hip/groin pain. Methods: The review was registered as PROSPERO CRD42014007416 and a comprehensive, systematic search was conducted in June 2014. Inclusion criteria were: cross-sectional, cohort or case-control study designs of n>10 that examined outcome measures differentiating athletes with and without hip/groin pain. Two authors independently screened search results, assessed study quality, and performed data extraction. Methodological heterogeneity was determined and data pooled for meta-analysis when appropriate. A best evidence synthesis was performed on the remaining outcome measures. Results: Of 2251 titles identified, 17 articles were included of which 10 were high quality. Sixty two different outcome measures were examined, 8 underwent meta-analysis. Pooled data showed strong evidence that athletes with hip/groin pain demonstrated: pain and lower strength on the adductor squeeze test, reduced range of motion in hip internal rotation and bent knee fall out; however, hip external rotation range was equivalent to controls. Strong evidence was found that lower patient-reported outcome (PRO) scores, altered trunk muscle function, and moderate evidence of bone oedema and secondary cleft sign were associated with hip/groin pain. Conclusions: PROs, pain and reduced strength on the adductor squeeze test, reduced range of motion in internal rotation and bent knee fall out are the outcome measures that best differentiate athletes with hip/groin pain from those without this pain

Risk Factors and Population-Attributable Fractions for Incident Hip Osteoarthritis

Background: Despite the huge burden of hip osteoarthritis (OA) and the lack of effective treatment, research into the primary prevention of hip OA is in its infancy. Purpose: We sought to evaluate risk factors for incident clinical and incident radiographic hip OA among middle-aged and older adults, to evaluate the importance of risk factors from a preventive perspective, and to estimate the percentage of new cases attributable to these risk factors. Methods: We retrospectively reviewed data from the Rotterdam study, an open-population cohort study of individuals aged 55 years or older. Data including baseline age, sex, body mass index, smoking status, education level, diagnosis of diabetes, C-reactive protein (CRP), cam morphology, acetabular dysplasia, radiographic thumb OA, radiographic hip OA, and hip pain were assessed for their association with incident clinical hip OA and incident radiographic hip OA separately, after 11 years of follow-up. The population-attributable fractions (PAFs) of statistically significant modifiable risk factors were calculated, as well. Results: New onset of clinical hip OA was seen in 19.9% (544 of 2729) and incident radiographic hip OA in 9.9% (329 of 3309). Female sex, education level below average (PAF 21.4%), and radiographic hip OA (PAF 3.4%) were statistically significantly associated with incident clinical hip OA. Female sex, age, overweight (PAF 20.0%), cam morphology (PAF 7.9%), acetabular dysplasia (PAF 3.6%), and radiographic thumb OA (PAF 4.7%) were statistically significantly associated with radiographic hip OA. Conclusions: Our retrospective analysis suggests that, from a primary prevention perspective, the most important modifiable risk factors among middle-aged and older individuals may be low educational level for incident clinical hip OA and overweight for incident radiographic hip OA. Further study is warranted.</p

Cam morphology is strongly and consistently associated with development of radiographic hip osteoarthritis throughout 4 follow-up visits within 10 years

Objective: To determine the association between cam morphology and the development of radiographic hip osteoarthritis (RHOA) at four time points within 10-year follow-up. Design: The nationwide prospective Cohort Hip and Cohort Knee study includes 1002 participants aged 45–65 years with 2-, 5-, 8-, and 10-year follow-ups. The associations of cam morphology (alpha angle &gt;60°) and large cam morphology (alpha angle &gt;78°) in hips free of osteoarthritis at baseline (Kellgren &amp; Lawrence (KL) grade &lt;2) with the development of both incident RHOA (KL grade≥2) and end-stage RHOA (KL grade≥3) were estimated using logistic regression with generalized estimating equation at each follow-up and using Cox regression over 10 years, adjusted for age, sex, and body mass index.Results: Both cam morphology and large cam morphology were associated with the development of incident RHOA at all follow-ups with adjusted Odd Ratios (aORs) ranging from 2.7 (95% Confidence interval 1.8–4.1) to 2.9 (95% CI 2.0–4.4) for cam morphology and ranging from 2.5 (95% CI 1.5–4.3) to 4.2 (95% CI 2.2–8.3) for large cam morphology. For end-stage RHOA, cam morphology resulted in aORs ranging from 4.9 (95% CI 1.8–13.2) to 8.5 (95% CI 1.1–64.4), and aORs for large cam morphology ranged from 6.7 (95% CI 3.1–14.7) to 12.7 (95% CI 1.9–84.4). Conclusions: Cam morphology poses the hip at 2–13 times increased odds for developing RHOA within a 10-year follow-up. The association was particularly strong for large cam morphology and end-stage RHOA, while the strength of association was consistent over time.</p

The relationship between cam morphology and hip and groin symptoms and signs in young male football players

Background: Conflicting and limited high-quality prospective data are available on the associations between cam morphology and hip and groin symptoms and range of motion (ROM). Objectives: This cross-sectional cohort study investigated associations between cam morphology presence, size and duration and symptoms and ROM. Methods: Academy male football players (n = 49, 17-24 years) were included. Standardized antero-posterior pelvic and frog-leg lateral radiographs were obtained at baseline, 2.5- and 5-year follow-up. The femoral head-neck junction was quantified by: Visual score. Cam morphology (flattening or prominence), large cam (prominence). Alpha angle.

What is the Prevalence of Hip Intra-Articular Pathologies and Osteoarthritis in Active Athletes with Hip and Groin Pain Compared with Those Without? A Systematic Review and Meta-Analysis

Background In athletes, hip and groin pain is considered to be associated with hip intra-articular pathologies and hip osteoarthritis (OA). A greater understanding of the relationship between hip and groin pain and imaging fndings is required. Objective Our objective was to undertake a systematic review and meta-analysis to determine the prevalence of hip intraarticular pathologies and hip OA in athletes with and without hip and groin pain. Methods Seven electronic databases were searched on 29 January 2018 for studies investigating the prevalence of hip intraarticular pathologies and hip OA using X-ray, magnetic resonance imaging, magnetic resonance arthrography or computed tomography. The search, study selection, quality