Diagnostic Accuracy of Hip Joint Ultrasound for Detection of Calcium Pyrophosphate Deposition.

OBJECTIVE: Calcium Pyrophosphate Crystal Deposition (CPPD) disease is a chronic and disabling arthropathy. Ultrasound (US) has been shown to be a tool with high sensitivity and specificity for the diagnosis of CPPD disease, but its value at the hip joint has not yet been determined. Therefore, our objective was to evaluate the diagnostic accuracy of US for the identification of calcium pyrophosphate (CPP) crystals in the hip joint as compared with histopathology. METHODS: Diagnostic test study involving patients over 50 years of age with osteoarthritis, scheduled for hip replacement surgery. US was performed on the affected hip. Acetabular fibrocartilage (FC) and hyaline cartilage (HC) of the femoral head were assessed, and a dichotomous score was used for the presence/absence of CPP crystals. Synovial fluid (SF) was obtained from the affected hip and examined using polarized light microscopy. Histopathological examination was performed by an experienced pathologist in search for CPP crystals in FC and HC samples. RESULTS: One hundred patients were enrolled, of whom 62% were found to have hyperechoic areas suggestive of CPP deposition on US examination. Pathological evaluation revealed a prevalence of 61% of CPP crystals. The sensitivity, specificity and the positive predictive and the negative predictive values were 90%, 82%, 89%, and 84%, respectively. The area under the curve for US compared with histopathology for the diagnosis of hip CPPD was 0.86 (CI 95% 0.78-0.94). CONCLUSION: US is a valid imaging modality with good diagnostic accuracy for the detection of hip CPPD.

[Incidence of hip and knee prosthetic infections in a specialized center of Mexico City]. / Incidencia de infecciones protésicas primarias de cadera y rodilla en un centro de la Ciudad de México.

BACKGROUND: Hip and knee prosthetic replacements have proven to be the most appropriate treatment in the joints that do not benefit from medical or arthroscopic interventions; however, infections are the most feared complication. It is recommended that the incidence of infection should not exceed 2%. MATERIAL AND METHODS: This was an observational, prospective, longitudinal and observational study conducted in patients fitted with a prosthetic joint from August 2011 to July 2012. Patients were followed up pre and post-surgery for one year to identify a prosthetic infection, diagnosed using international parameters. We calculated the incidence of prosthetic infection, as well as the incidence density. RESULTS: A total of 339 patients (179 hip and 160 knee) were included. Variations in the time of pre-operative antibiotics' administration were observed. Six prosthetic infections were identified with an incidence rate of 1.79/339 arthroplasties, 2.2/179 hip procedures, and 1.25/160 knee arthroplasties. An incidence density of 0.02/year for hip arthroplasties and 0.11/year for knee procedures was identified. There were 4 infections of hip and 2 of knee. Five infections were acute and one chronic. The isolated microorganisms were E. faecalis, S. epidermidis (2), S. mitis, S. aureus and P. stomatis. CONCLUSIONS: The incidence of prosthetic joint infection in the first year of follow-up at our centre is within the recommended parameters. Surgical techniques and organizational practices influence the results.

[Total hip arthroplasty in patients with cerebral vascular event. Case report]. / Artroplastia total de cadera primaria en paciente con evento vascular cerebral. Reporte de un caso.

INTRODUCTION: Associated neurological disorders pose a challenge hip joint reconstruction. The imbalance and poor muscle tone predispose to dislocation and loosening of the prosthesis. CLINICAL CASE: The following is the case of a 67 years old patient with a hemorrhagic cerebral vascular event with a secondary left hemiparesis. Ten years later had a femoral neck fracture on the affected side. Initially she was treated with conservative management resulting in pain and discapacity, valued with WOMAC scale as 12 points. Two years later was treated with total hip arthroplasty with large diameter femoral head. We present the follow up of 41 months, asymptomatic, walking using a cane and a WOMAC score of 41, with no signs of radiological loosening or dislocation. CONCLUSIONS: There is no experience documented in neurological disorders associated with hip diseases that requires a total hip arthroplasty. Loosening of the implants, dislocation and heterotopic ossification has been described as complications of the procedure. Large heads in total hip arthroplasty and a correct surgical technique associated with a multidisciplinary management in patients with neurological disorders offers an opportunity as a treatment in patient with hip disorders.