Magnetic resonance imaging in the evaluation of meniscal tear

Background: Magnetic resonance imaging (MRI) has been recognized as the imaging method for non-invasive evaluation of knee pathology, particular meniscus and ligaments. Objective: Compare the sensitivity, specificity, and accuracy of MRI in the detection of meniscal tears with arthroscopy. Material and methods: Twenty-seven patients who were diagnosed as meniscal tear on arthroscopy with preoperative MRI were included in this study between January 2003 and June 2008. MRI was performed with a 1.5 Tesla Signa Horizon Echospeed MRI for eight patients between January 2003 and June 2005 and a 1.5 Tesla Signa Excited HD MRI for nineteen patients between July 2005 and June 2008. The location of meniscal tear was evaluated by studying three areas: anterior horn, body and posterior horn. Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of the anterior horn, body, posterior horn and overall meniscus were calculated. Results: The sensitivity of MRI for detecting meniscal tears at the anterior horn, body, posterior horn, and overall medial meniscus was 42.9%, 87.5%, 94.1%, and 81.3%, respectively. The specificity was 95.0%, 84.2%, 81.8%, and 88.0%, respectively. The accuracy was 81.5%, 85.2%, 89.3%, and 85.4%, respectively. The PPV was 75.0%, 70.0%, 88.9%, and 81.2%, respectively. The NPV was 82.6%, 94.1%, 90.0%, and 88.0%, respectively. The sensitivity of MRI for detecting meniscal tears at the anterior horn, body, posterior horn and overall lateral meniscus was 0%, 100%, 85.7%, and 80.0%, respectively. The specificity was 100%, 100%, 90.5% and 97.2%, respectively. The accuracy was 96.0%, 100%, 90.5%, and 97.2%, respectively. The PPV was 100%, 75% and 80%, respectively. The NPV was 96.3%, 100%, 95.0%, and 97.2%, respectively. Conclusion: MRI is a helpful technique to detect meniscal tear with different sensitivity and accuracy on the meniscal location

Allograft replacement in limb salvage surgery for bone tumors.

A retrospective study of a series of eleven patients with active, aggressive benign and malignant bone tumors who were treated by radical resection and massive match-sized allograft replacement was reviewed. There were seven giant cell tumors and four osteosarcoma cases involving mainly either the lower end of the femur or upper end of the tibia. The age of the patients ranged from 11 to 50 years. As the follow-up period was rather short, ranging from 9 to 60 months, the patients are all still alive. Complications included two infections, one local recurrence, and two with resorption of the articular surface of the osteoarticular graft. Though psychosocial benefit was gained in patients with this limb salvage procedure, functional evaluation did not yield a satisfactory result.

The biomechanical study of atlantoaxial fixation.

Recent studies of various C(1-2) constructs have confirmed superior stability with transarticular screw fixation. In the meantime, our study on the C2 morphology in Thai people found about 4 per cent of the pedicles were too small for the 3.5 mm. C(1-2) transarticular screw. In order to select a smaller screw to use in this operation, we performed a biomechanical testing of 2 sizes of screw (2.7 mm, 3.5 mm) for transarticular screw fixation and Gallie's wiring, comparison in terms of stiffness in flexion, extension, torsion, anterior and posterior shear loads. There were no statistical differences of the stiffness between 2.7 mm and 3.5 mm transarticular screw fixation in all directions, whereas there were significantly greater stiffness of transarticular screw over Gallie's wiring in various directions (P<0.05).

Plate-screw-wiring technique for the treatment of periprosthetic fracture around the hip: a biomechanical study.

Biomechanic properties, bending stiffness and torsional strength, were determined in three different fixation techniques including lateral plating, lateral plating with cerclage wires, and 90 degrees-90 degrees anterior and lateral plating employed in treatment of the femoral shaft fracture with the presence of a femoral prosthesis. Five pairs of human femora with a man made cemented periprosthetic Johansson et al fracture classification type II were used in the experiments. The study showed that 90 degrees-90 degrees anterior and lateral plating produced the best increment in both biomechanic properties. In clinical practice, most of the soft tissue around femoral bone had to be dissected to do this technique, which would affect bone healing. Further study regarding the other properties, benefits, and disadvantages of these three techniques should be conducted before selecting the best method for treatment of the patients.