Purpose: Accurate acetabular cup positioning is essential to successful total hip arthroplasty (THA). Intra-operative navigation of the acetabular component can optimize positioning, but often necessitates registration of the pelvis in the supine position. The majority of surgeons use the lateral position, however, which hides commonly employed registration landmarks. The purpose of this study was to identify novel anatomical landmarks for use in navigated THA from the lateral approach. Method: We identified 156 patients that underwent pelvic CT scans for non-orthopaedic reasons from which 60 patients (mean age 62 years; 30 males, 30 females) were included in the study. CT scans were analyzed with sophisticated software (region grow, isosurface creation, and geometry overlay features). Saved coordinates from each scan were inputted into the program MATLAB (Mathworks, Natick, MA), v7.0, on a Macintosh-based workstation. A code was created to be able to calculate the normal vector for both planes and then calculate the angle formed between the normal vectors. The anterior plane (pubic tubercle (PT) and anterior superior iliac spine (ASIS)) was defined in addition to a series of lateral planes by retaining the ipsilateral PT and ASIS from the anterior plane, plus a variable third landmark. Angles obtained were those between the anterior and lateral planes. Angle conversions between the planes were analyzed using a paired t-test with a p-value of < 0.05 accepted as significant. Results: The list of landmarks acquired included those used for supine registration (PT and ASIS) in addition to: posterior superior iliac spine (PSIS); posterior inferior iliac spine, (PIIS); ischial tuberosity (IT); tuber-culum of the iliac crest (TIC); and a line drawn along the outer lip of the iliac crest. The angle between the anterior plane and the novel lateral planes did not show a significant level of variance for two of the proposed lateral planes (P< 0.05). Conclusion: An imageless navigation system in THA that can be accurately employed in the lateral position will benefit many surgeons. The invariance in angle calculations for the lateral planes calculated using the PSIS and the TIC suggest that they could be novel pelvic landmarks for lateral plane registration

Aims: We evaluated the results of molecular diagnostics to see if they can help in conþrming an accurate diagnosis quickly in cases of Ewingñs sarcomas. Methods: We did biopsies and genetic studies in 19 patients (8 females, 11 males Ð 35±19 years old) with a bone tumor with clinical and imaging signs of Ewingñs sarcoma. Cytogenetic examination aimed at tracing characteristic products of the hybrid genes of the tumor. We did molecular analysis with RT-PCR. Results: In ten patients biopsy conþrmed the diagnosis of Ewingñs sarcoma. The genetic tests of 12 patients came to a clear conclusion. In 7 cases (4 Ewingñs sarcomas histologicaly) we had no answer. In seven cases we found products of hybrid genes Ews/Fli and Ews/Erg. These are the result of fusion of genes from chromosomes 22q12, 11q24 and 21q22 and the characteristic chromosomal translocation of Ewingñs sarcoma between exon 7 and exon 6 of the Fli fusion gene was conþrmed. Five cases had no characteristic numerical or structural chromosomal abnormalities. Histologic and cytogenetic diagnoses of Ewingñs sarcoma concur in þve cases. One case of Ewingñs sarcoma was not conþrmed with genetic diagnostics. Two cases with gene mutations characteris tic of Ewingñs sarcoma had an histologic diagnosis of an osteosarcoma. Conclusions: Malignant cells commonly exhibit speciþc chromosomal deletions, which may lead to tumor formation. Our cases show the strong relation between Ewingñs sarcoma and certain chimerical genetic transcriptions. Identical cytogenetical translocations in a few cases of other tumors and their absence in some Ewingñs sarcomas is confusing and indicates their common origin from a primitive tumor

Aims

The metabolic variations between the cartilage of osteoarthritis (OA) and Kashin-Beck disease (KBD) remain largely unknown. Our study aimed to address this by conducting a comparative analysis of the metabolic profiles present in the cartilage of KBD and OA.