Purpose. To determine if clinical outcomes are correlated with center of rotation (COR) in patients implanted with a viscoelastic total disc replacement (VTDR). Methods. Fifty patients with single-level, symptomatic lumbar DDD between L4 and S1 were enrolled in a clinical trial of a VTDR across three surgical centres. A comprehensive, independent review and statistical analysis of both clinical and radiographic outcomes was performed and analyzed for correlations. Data from preoperative through 2 years were available. The COR was calculated for the index levels and compared to data for an asymptomatic population. Each COR coordinate was classified as abnormal if outside of the 95% confidence interval for an asymptomatic population. Results. At most recent follow-up, 69% of the patients had achieved at least a 15 point Oswestry Disability Index (ODI) improvement. 76% of the patients achieved at least a 10 point improvement. At most recent follow-up, 78% of cases had a normal COR-X and 92% had a normal COR-Y. Results from three statistical tests show the association between COR-X and outcomes. 1) Based on latest available time point for each patient, the improvement in ODI score was significantly better for patients with a normal anterior-posterior (AP) coordinate of the COR (P=0.03). 2) Anterior COR corresponded with anterior placement of the device in the disc space, and patients were almost 7 times less likely to achieve at least a 15 point improvement in the ODI score if the COR was positioned too anteriorly. 3) This effect was also seen in the average AP coordinate of the COR for patients who achieved a 15 point ODI improvement. Conclusions. A viscoelastic TDR can restore a normal COR. This is the first study to show that restoration of a normal COR correlates with a significant and clinically relevant improvement in patient disability

Background. Morton's neuroma is the enlargement of an interdigital nerve most commonly located between the third and fourth metatarsals. It is susceptible to entrapment and therefore is a common cause of disabling foot pain. Greek foot is a normal variant where the first metatarsal is shorter than the second metatarsal. To our knowledge there is currently no reported association between Greek foot and Morton's neuroma in the literature. Material and methods. Retrospective study of 184 patients. Two separate cohorts were recruited. Cohort (A): 100 randomly selected patients with no foot pain. Cohort (B): 84 patients with foot pain and Mortons's neuroma. The foot shape was determined by using a self-assessment tool and plain radiographs. Statistical analyses were performed using the Chi square test on the association between Greek foot and Morton's neuroma. A value of P = < 0.05 was considered statistically significant. Results. Our study shows a statistically significant association between Greek foot and Morton's neuroma with a prevalence of Greek foot in Cohort (A) of 20% (95% C.I.:12%–28%) and in Cohort (B) of 63% (95% C.I.:53%–73%). (P = 2.6 × 10. −9. ). Discussion. This study has shown a possible association between the presence of a Greek foot and the presence of Morton's neuroma. We can conclude that people with foot pain are more likely to have Greek foot than Egyptian foot and that the prevalence of Greek foot is higher in patients with Morton's neuroma than in the asymptomatic population. Although our study design has limitations and does not allow full statistical analysis, we do believe that the shown association between Greek foot and Morton's neuroma can help clinicians and other health care providers in establishing the diagnosis of Morton's neuroma in patients with a painful foot

INTRODUCTION:. Acetabular retroversion has been implicated as a risk factor for the development of early hip osteoarthritis. In clinical practice standard osseous signs such as the cross-over sign (COS) and the posterior wall sign (PWS) are widely used to establish the diagnosis of acetabular retroversion on plain radiographs. Despite standardized radiological evaluation protocols, an increased pelvic tilt can lead to a misdiagnosis of acetabular retroversion in AP radiographs and 2D MR or CT scans. Previous studies have shown that the elimination of observer bias using a standardized methodology based on 3D-CT models and the anterior pelvic plane (APP) for the assessment of COS and PWS results in greater diagnostic accuracy. Using this method a prevalence of 28% for COS and 24% for PWS has been found in a cohort of patients with symptoms indicative of FAI, however the prevalence of both signs in asymptomatic adults remains unknown. This study therefore sought to establish the prevalence of the COS and PWS in relation to the APP in an asymptomatic population using a reliable and accurate 3 D-CT based assessment. METHODS:. A large pool of consecutive CT scans of the pelvis undertaken in our department for conditions unrelated to disorders of the hip was available for analysis. Scans in subjects with a Harris hip score of less than 90 points were excluded leaving a sample of 100 asymptomatic subjects (200 hips) for this study. A previously established 3D analysis method designed to eliminate errors resulting from variations in the position and orientation of the pelvis during CT imaging was applied to determine in order to assess the prevalence of the COS and PWS in relation to the APP. Here, the acetabuli were defined as retroverted if either the COS, PWS or both were positive. RESULTS:. From the total of 200 hips a positive COS was identified in 24% (48/200) and a positive PWS was detected in 6.5% (13/200) relative to the APP using the CT data. A. In male adults a COS was observed in 25.4% (29/114) and a PWS in 10.5% (12/114). In female adults a COS were observed in 22.1% (19/86) and a PWS in 1.2% (1/86). DISCUSSION:. The high incidence of acetabular retroversion observed using an accurate 3D-CT based methodology shows that this anatomic configuration might not differ in frequency between asymptomatic individuals and patients with symptomatic FAI. Patients presenting with hip pain and evidence of FAI should therefore be subjected to strict diagnostic scrutiny, as the presence of a COS and/or PWS shows a poor correlation with the presence of symptomatic disease. In our collective of asymptomatic adults the COS showed a higher incidence than the PWS. Additionally a deficiency of the posterior acetabular wall was rare in asymptomatic adults compared to FAI patients. Therefore, the question whether an abnormal acetabular version does indeed lead to the development of osteoarthritis in all patients warrants further study. Although an association between osteoarthritis and femuro-acetabular impingement is believed to exist, long-term epidemiological studies are needed to establish the natural history of these anatomical configurations

Introduction. Acetabular dysplasia cause hip joint osteoarthritis(OA) by change hip mechanism. However, to our best knowledge, no studies have been published using prospectively collected data from asymptomatic young age volunteers, precise radiographic method. The purpose of this study is to evaluate the prevalence of hip dysplasia in asymptomatic Korean population as one of the most important risk factor of hip OA. Materials & Methods. From December 2014 to March 2015, we investigated prospectively collected retrospectively reviewed data of 200 asymptomatic volunteers 400 hips in age between 18 and 50 years recruited from our institution. Pelvic radiographs were taken and all radiographs were reviewed by 2 experienced orthopedic surgeons. Lateral center-edge angle(LCEA), Sharp angle, Tonnis angle and acetabular width-depth ratio were measured. We analyzed the statistical differences of these values between sex by Mann-Whitney U test and independent t-test. Pearson's correlation coefficient was used to measure the relationship between dysplasia parameters. Results. On the Pelvic AP view, 60 of the 400 hips (15%) were dysplastic hip as LCEA <20°. In 146 male hips, 17 hips (11.6%) were LCEA <20°. In 254 female hips, 43 hips(16.9%) were LCEA <20°. There was no strong correlation of LCEA with other measurements. Conclusion. There are large number of asymptomatic dysplastic hips in Asian population compared previously investigated

Few epidemiological studies from Asian countries have addressed this issue and reported that FAI is less prevalent in Asian population. The purpose of this study was to determine the prevalence of radiographic hip abnormalities associated with FAI in asymptomatic Korean volunteers. The authors hypothesized that the prevalence of FAI in Korean population would not be less than that in western population. Two hundred asymptomatic volunteers with no prior hip surgery or childhood hip problems underwent three-view plain radiography (pelvis anteroposterior (AP) view, Sugioka view, and 45° Dunn view) of both hips. Cam lesions were defined as the presence of the following signs on each views: pistol-grip deformity, osseous bump at the femoral head-neck junction, flattening of the femoral head-neck offset, or alpha angle >50°. Pincer lesions were determined by radiographic signs, including crossover sign, posterior wall deficient sign, or lateral center-edge (CE) angle >40°. Only positive cases agreed by both observers were defined as true FAI-related deformities. There were 146 male and 254 female hips, with a mean age of 34.7 years. On pelvis AP view, the prevalence of pistol grip deformity, bump, flattening, and alpha angle >50° was 1.3% (male 3.4%, female 0%), 0.8% (male 2.1%, female 0%), 0.8% (male 2.1%, female 0%), and 1.0% (male 2.7%, female 0%), respectively. On Sugioka view, the prevalence of bump, flattening, and alpha angle >50° was 9.8% (male 14.4%, female 7.1%), 13.5% (male 20.5%, female 9.4%), and 14.0% (male 26.7%, female 6.7%), respectively. On 45° Dunn view, the prevalence of bump, flattening, and alpha angle >50° was 8.0% (male 14.4%, female 4.3%), 17.5% (male 27.4%, female 11.8%), and 27.5% (male 44.5%, female 17.7%), respectively. The prevalence of cam lesion which was identified on at least one radiograph was 42.5% (male 62.3%, female 31.1%). The prevalence of cam lesion which was identified on ≥2 radiographs was 19.3% (male 30.8%, female 12.6%). The prevalence of cam type FAI (at least one cam lesion) was 2.0% (male 5.5%, female 0%) on pelvis AP view, 25.8% (male 37.0%, female 19.3%) on Sugioka view, and 35.8% (male 55.5%, female 24.4%) on 45° Dunn view. On pelvis AP view, the prevalence of crossover sign, posterior wall sign, and CE angle >40° was 20.0% (male 23.3%, female 18.1%), 20.8% (male 22.6%, female 19.7%), and 2.0% (male 2.7%, female 1.6%), respectively. The prevalence of pincer type of FAI (at least one pincer lesion) was 23.0% (male 27.4%, female 20.5%). In asymptomatic Korean volunteers, the prevalence of cam type FAI was low on AP pelvis radiographs, whereas the prevalence of cam type FAI on Sugioka and 45° Dunn view was found to be comparable to that previously reported in Western populations. The prevalence of pincer type FAI in asymptomatic Korean volunteers was also comparable that in Western populations and was similar in both gender. Considering the high prevalence of FAI morphologic features on plain radiographs in asymptomatic Korean populations, it is also important to determine whether FAI is a cause of hip pain when considering surgery in Asian patients

Some military personnel are having Femoral Acetabular Impingement (FAI) surgery. The use of the alpha angle (AA) to help assess the diagnosis is common. Currently there are no standardised values available across a asymptomatic pre-arthritic population. Retrospective analysis of 200 consecutive individuals (400 hip joints) with ages 20 to 50, who had a CT performed between 1 Apr 2011 and 29 Nov 2011 due to abdominal pathology. The AA of Notzli was measured on the axial view. The mean AA value was 53.5 (95%CI 1.30) for Right hips and 53.4 (95% CI 1.31) for the left. In age 20–30 Right 52.6 (95%CI 3.5) the Left 52.0 (95%CI 2.9), 31–40 Right 53.9 (95%CI 2.5) Left 53.4 (95%CI 3.1), 41–50 Right 53.8 (95% CI 1.9) Left 53.2 (95% CI 1.8). Mean male Right 52.9 (95% CI 1.5) Left 53.2 (95%CI 1.9) Female Right 52.5 (95% CI 1.5) Left 49.9 (95% CI 1.6). 144/400 (37%) of patients had angle >55 degrees. Previous literature suggests an AA >55 degrees is diagnostic of FAI, we suggest that the AA is highly variable across age and sex and that >1/3rd of asymptomatic patients will have an AA that was previously regarded as abnormal