BACKGROUND: Femoroacetabular impingement (FAI) is considered one of the main causes of hip osteoarthritis in young adults, especially in athletes. In recent years, morphological changes in FAI in the hip have been linked to early and intense sports participation, but studying top-level athlete samples is not easy. This paper presents the prevalence of FAI radiological markers in 120 active white male professional football players in the Spanish First Division League (La Liga) and compares the morphological changes with those of a control group of healthy individuals without significant sport activity.
METHODS: The precontract medical evaluation hip X-rays of 120 white male professional football players from four different First Division Spanish football teams were prospectively filed and retrospectively reviewed by a dedicated skeletal radiologist. The footballers\' hip X-rays were compared with those of a control group of 80 healthy individuals (age-sex matched) without significant sport activity (obtained from routine work medical checks).
RESULTS: The femoral head-neck deformity associated with the Cam type of femoroacetabular impingement was observed in 61.6% of professional football players and only in 11.6% of the control group (p <0.01). The presence of \"herniation pit\" (11.6%) and os acetabuli (13.3%) also reached statistical significance in the professional football players group. In the other analyzed parameters, no statistically significant differences between the groups were observed.
CONCLUSIONS: White professional top-level football players have an increased incidence of abnormal lateral epiphyseal extension (\"pistol grip deformity\"), os acetabuli and herniation pits.

BACKGROUND: Congenital femoral deficiency (CFD) is a challenging and complex condition that causes limb lengthening. We focused on the clinical and radiographic results of SUPERhip procedures in patients with congenital femoral deficiency type 1b, according to Paley\'s classification, prior to femoral lengthening.
METHODS: We reviewed all records and radiographs of patients who underwent this procedure between 2005 and 2020. We included 26 patients, with clinical and radiographic assessments performed during pre- and post-operative evaluations.
RESULTS: There were twenty-six patients (15 right vs. 11 left), with a mean age of 7 years (1-18). Most of the patients were female (17 patients; 65.4%). Twenty (76.9%) patients were undergoing their first procedure and six (23.1%) had already undergone a previous surgery. There was a significant improvement in all radiographic parameters, with the mean preoperative and postoperative Neck-Shaft Angle (NSA) being 72.3 ± 7.1° vs. 133.1 ± 12.7°, the Center-Edge Angle (CEA) 16.8 ± 9.8° vs. 33.5 ± 14.1°, and the Acetabular Index (AI) 27.8 ± 6.9° vs. 16.4 ± 6.8°, respectively. The complication rate was 15.4%, predominantly affecting patients under 5 years old.
CONCLUSIONS: The SUPERhip procedure is an effective and reproducible technique for clinical and radiographic correction to a significant degree in patients with Paley\'s type 1b CFD, in preparation for bone lengthening surgery.

We studied the association of Enthesitis related arthritis (ERA) the most common variant of juvenile idiopathic arthritis (JIA) in Asians, with HLA-G and -E polymorphisms. HLA-G (14 bp Ins/Del rs371194629, +3142 rs1063320, +3187 rs9380142) and HLA-E (rs1264457, and rs2844724) polymorphisms were analyzed in 127 patients with ERA and 381 ethnically matched healthy controls with TaqMan 5\'-nuclease assay using allele-specific fluorogenic oligonucleotide probes. HLA-G and -E polymorphisms were not found to be associated with susceptibility to ERA. HLA-G +3187 (rs9380142) G allele was associated with hip arthritis (Pc = 0.04, OR = 2.22, 95%CI = 1.07-4.63) and hip deformity (Pc = 0.02, OR = 2.51, 95%CI = 1.16-5.43). HLA-B*27 was positive in 91. HLA-E rs1264457 G and rs2844724 T alleles may be associated with B*27 positivity in ERA. Among HLA-G, -E haplotypes, frequency of -InsGAAC was significantly higher in patients than healthy controls (Pc = 0.003). In conclusion, HLA-G and HLA-E haplotype -InsGAAC may be associated with susceptibility to ERA and HLA-G +3187 rs9380142 A>G polymorphism may be a poor prognostic marker for progression to hip arthritis and deformity in ERA-JIA.

UNASSIGNED: The aim of this study is to assess the pelvis\'s morphology and spatial orientation of the acetabulum, and their relation to the severity of Congenital Femoral Deficiency (CFD) using 3D imaging. Defining these pathologies is crucial for adequate surgical correction.
UNASSIGNED: The shape and structure of the acetabulum and pelvis were evaluated in 14 children with unilateral CFD via 3D computed tomography (CT) scans, and then analysed with geometric morphometrics (Procrustes ANOVA). The association between pelvic directional asymmetry and CFD classifications (Aitken, Paley) was assessed. The affected acetabulum\'s orientation was compared to the non-affected side, and the variability of orientation in different CFD types was evaluated (bivariate correlation).
UNASSIGNED: The hemipelvis with CFD is characterized by a smaller acetabulum, a laterally curved ischium and a less upright ilium (p < 0.001). Multivariate regressions revealed a greater level of pelvis asymmetry in more severe types of CFD (p < 0.001). The acetabulum orientation assessment showed a significant decrease in mean anteversion (1.3°) and inclination (9.6°) angle, when compared to the non-affected side (26°and 17.1° respectively; p < 0.001).
UNASSIGNED: The affected side of the pelvis is considerably smaller and more deformed, and this should be considered during limb lengthening. The acetabulum presents with significant dysplasia due to its severe retroversion and steepness (superoposterior distortion). This should not be interpreted as a simple wall deficit, but as a complete acetabular misalignment (often misinterpreted in 2D imagery). Using transiliac osteotomies (e.g. Dega, Salter) is debatable due to abnormal acetabular orientation (superoposterior malalignment). Therefore, alternative options, e.g. San Diego or triple pelvic osteotomy, should be considered.

OBJECTIVE: This study aimed at investigating the agreement between predefined quantitative parameters of hip morphology derived from magnetic resonance imaging (MRI) and virtual range of motion (ROM) analysis using computed tomography (CT) as standard of reference.
METHODS: Twenty patients (13 females, 7 males, 16-59 years) with hip deformities underwent MRI prior to surgery. Clockwise alpha angle, femoral head and neck diameter, collum caput diaphysis angle, femoral torsion, center-edge angles, acetabular coverage of the femoral head, sourcil angle, and acetabular anteversion were measured. Additionally, tern single and combined movements were simulated using a motion analysis program. The MRI findings were compared with the corresponding results obtained by CT. Correlation of MRI with CT was assessed using different statistical methods (intraclass correlation coefficient, Bland-Altmann plot, two one-sided t test), and linear regression analysis was performed.
RESULTS: The results showed near-perfect intraclass correlation coefficients (ICCs) for anteversion (0.95), acetabular sector angles (0.98-0.99), sourcil angle (0.95), and acetabular coverage (anterior 0.96, posterior 0.99). Intermethod correlation for femoral parameters showed almost perfect agreement except for the alpha angle (0.73-0.97). No significant proportional bias was detected for traditional acetabular and femoral parameters. ROM analysis was performed for 370 movements in 37 hips. For 78.4% (290/370) of the movements analysed, neither CT nor MRI detected impingement across the physiological ROM. For 18.6% (69/370) of the movements, impingement was detected by both CT and MRI, while 2.2% (8/370) of the movements with impingement in CT showed no impingement in MRI, and 0.8% (3/370) of the movements with impingement in MRI had no corresponding result in CT.
CONCLUSIONS: Finally, it was concluded that MRI-based assessment of hip morphology and virtual ROM analysis is feasible and can be performed with good intermethod agreement in comparison to the gold standard (CT). Therefore, MRI appears to be substantially equivalent to CT for use in virtual ROM analysis and so may reasonably be used in place of CT for this purpose.

UNASSIGNED: Previous work has examined the impact of delay of diagnosis in slipped capital femoral epiphysis (SCFE) but not the impact of delay in treatment after radiographic diagnosis. Due to requirements for long distance transportation from less developed regions for many of our patients, our hospital was able to study variation in time between diagnosis and surgery for SCFE, as related to slip severity.
UNASSIGNED: This is a retrospective review of patients treated for SCFE between 2005 and 2014 at a tertiary care paediatric hospital. Demographics, time between diagnosis and surgery, radiographic deformity (Southwick angle), postoperative complications and need for further surgery were variables of interest. Statistical analysis included Pearson and Spearman rank correlations and chi-squared tests.
UNASSIGNED: The study sample included 147 hips (119 patients). Mean time between radiographic diagnosis and surgery was 20.9 days (sd 46, 0 to 321). The mean Southwick angle (SA) at the time of surgery was 31.9˚ (sd 19.6˚, 1° to 83˚). There was a significant relationship between increased delay and increased SA (0.34, p < 0.001). Increased SA was correlated with need for future significant surgery (0.27, p < 0.01).Patients from less-developed regions, with barriers to timely care, had moderate and severe deformity (SA) (p < 0.01), and required significant further surgery more often than SCFE patients from the local population (p < 0.01).
UNASSIGNED: The unique referral environment of our hospital provided an opportunity to examine traditional recommendations for treating SCFE promptly after radiographic diagnosis. Delay in treatment is correlated with increased radiographic deformity.
UNASSIGNED: III.

Patients with advanced hip arthritis can present with multifactorial limb length discrepancies (LLDs) owing to bony shortening from growth arrest, proximal hip migration, soft-tissue contractures, and pelvic obliquity. The patient perceives an LLD that is a combination of true LLD and apparent LLD.
We retrospectively reviewed 7 cases with multifactorial mean perceived LLD of 7.7 cm (range, 3.6-11 cm) that underwent primary total hip arthroplasty and auxiliary soft-tissue procedures. Perceived LLD, true LLD, and apparent LLD were defined and were compared before and after surgery in this cohort of patients with a mean follow-up of 57.4 months.
The mean perceived LLD at final follow-up was 1.0 ± 0.9 cm compared with that of 7.7 ± 2.6 cm preoperatively (P < .05). Postoperative true LLD was 0.7 ± 0.8 cm compared with that of 3.2 ± 0.8 cm preoperatively (P < .05). At final follow-up, all 7 patients were ambulating without any assistive devices and were satisfied with their surgical outcome.
With careful preoperative clinical and radiographic assessments as well as planning for multifactorial perceived LLD, this can be adequately corrected with primary total hip arthroplasty and auxiliary soft-tissue procedures resulting in good radiologic and functional outcomes.

OBJECTIVE: An experimental piglet model induces avascular necrosis (AVN) and deformation of the femoral head but its secondary effects on the developing acetabulum have not been studied. The aim of this study was to assess the development of secondary acetabular deformation following femoral head ischemia.
METHODS: Intracapsular circumferential ligation at the base of the femoral neck and sectioning of the ligamentum teres were performed in three week old piglets. MRI was then used for qualitative and quantitative studies of the acetabula in operated and non-operated hips in eight piglets from 48 hours to eight weeks post-surgery. Specimen photographs and histological sections of the acetabula were done at the end of the study.
RESULTS: The operated-side acetabula were wider, shallower and misshapen, with flattened labral edges. At eight weeks, increased acetabular cartilage thickness characterised the operated sides compared with non-operated sides (p < 0.001, ANOVA). The mean acetabular width on the operated side was increased (p = 0.015) while acetabular depth was decreased anteriorly (p = 0.007) and posteriorly (p = 0.44). The cartilage was thicker, with delayed acetabular bone formation, and showed increased vascularisation with fibrosis laterally and focal degenerative changes involving chondrocyte hypocellularity, chondrocyte cloning, peripheral pannus formation and surface fibrillation.
CONCLUSIONS: We demonstrate that femoral head AVN in the young growing piglet also induced, and was coupled with, secondary malformation in acetabular shape affecting both articular and adjacent pelvic cartilage structure, and acetabular bone. The femoral head model inducing AVN can also be applied to studies of acetabular maldevelopment, which is less well understood in terms of developing hip malformation. Cite this article: Bone Joint Res 2014;3:130-8.

BACKGROUND: Although cam-type femoroacetabular impingement is commonly associated with labral chondral damage and hip pain, a large proportion of asymptomatic individuals will have this deformity.
OBJECTIVE: To determine the incidence of hip pain in a prospective cohort of volunteers who had undergone magnetic resonance imaging (MRI) of their hips.
METHODS: Case control study; Level of evidence, 3.
METHODS: A total of 200 asymptomatic volunteers who underwent an MRI of both hips were followed for a mean time of 4.4 years (range, 4.01-4.95 years). Thirty were lost to follow-up, leaving 170 individuals (77 males, 93 females) with a mean age of 29.5 years (range, 25.7-54.5 years). All patients were blinded to the results of their MRI. All completed a follow-up questionnaire inquiring about the presence of hip pain or a history of hip pain lasting longer than 6 weeks since the original MRI. Each patient was asked to draw where the pain was on a body diagram.
RESULTS: Eleven patients (5 males, 6 females; 6.5% of sample; mean age, 29.9 years; range, 25.7-45.6 years) reported hip pain, of which 3 (1 male, 2 females) had bilateral pain for a total of 14 hips. Seven of the 14 painful hips had a cam-type deformity at the time of the initial MRI versus 37 of the 318 nonpainful hips (P = .0002). This gave a relative risk of 4.3 (95% confidence interval [CI], 2.3-7.8) of developing hip pain if cam deformity was present. Those 14 painful hips had a significantly greater alpha angle at the radial 1:30 clock position than did those who did not develop pain with a cam deformity: 61.5° (range, 57.3°-65.7°) versus 57.9° (range, 56.9°-59.1°), respectively (P = .05). A significantly greater proportion of patients (12%) with limited internal rotation ≤20° (versus 2.7% with internal rotation >20°) went on to develop hip pain (P = .009; relative risk = 3.1 [95% CI, 1.6-6.0]).
CONCLUSIONS: The presence of a cam deformity represents a significant risk factor for the development of hip pain. An elevated alpha angle at the 1:30 clock position and decreased internal rotation are associated with an increased risk of developing hip pain. However, not all patients with a cam deformity develop hip pain, and further research is needed to better define those at greater risk of developing degenerative symptoms.

BACKGROUND: It is a well-known fact that slipped capital femoral epiphysis (SCFE) is one of the causes of premature hip osteoarthritis and anterior femoroacetabular impingement. But there are no reliable, published diagnostic methods to measure the residual deformity of slipped capital femoral epiphysis. We propose using the lateral view head-neck index (LVHNI) measurement on a specific lateral X-ray view of the hip for this purpose.
OBJECTIVE: The LVHNI can detect and quantify the posterior translation of the femoral head and this index can be measured reliably.
METHODS: A prospective radiography study was performed by three observers. The hip X-rays of patients who were being treated by arthroplasty for hip osteoarthritis (total hip replacement or hip resurfacing) between January 2010 and December 2011 were analyzed. The LVHNI, which quantifies the posterior translation of the femoral head, was measured on a lateral view of the hip in 45° flexion/45° abduction/30° external rotation. The presence of a pistol grip deformity on A/P X-rays was also assessed.
RESULTS: The analysis was performed on 131 hips in 120 patients having an average age of 61 years (range 37-91). The chosen LVHNI threshold of 9% resulted in a sensitivity of 89.1% (95% CI: 78.8%-95.5%) and a specificity of 82.4% (95% CI: 71.2%-89.7%) for detecting the presence of a pistol grip deformity. Twenty percent of the hips with no visible deformity on A/P X-rays had a pathological index value. The inter-observer reproducibility was good for the LHNI [intraclass correlation coefficient (ICC): 0.61; 95% CI: 0.51-0.71] and for detecting a pistol grip deformity (ICC: 0.74; 95% CI: 0.62-0.85). The intra-observer reproducibility was excellent for the LHNI (ICC: 0.78; 95% CI: 0.57-0.88) and the pistol grip deformity (ICC: 0.85; 95% CI: 0.74-0.92).
CONCLUSIONS: The LVHNI is a reliable and reproducible tool to identify deformities secondary to SCFE on specific lateral femoral neck X-rays. If the index value is greater than 9%, SCFE sequelae may be present. In addition, this study showed that 20% of hips with normal A/P X-rays had a pathological index.
METHODS: Level IV, prospective diagnostic study without control group.