667ntraosseous gas collection is observed in various disorders. A pneumatocyst is a rare, gas-containing lesion in the bone. This condition is most frequently encountered in the ilium and the sacrum, adjacent to the sacroiliac joints [1]. Pneumatocysts in the cervical spine are rarely seen. The natural course of pneumatocysts is obscure. We report a case of a cervical intraosseous pneumatocyst in association with degenerative disk disease. The pneumatocyst radiologically changed to a fluid-filled cyst and was subsequently replaced by granulation tissue. To our knowledge, the radiologic phenomenon has never been described in the English-language literature. Case ReportA 56-year-old woman consulted an orthopedic unit complaining of neck pain and stiffness of 6 months' duration. Standard radiographs of the cervical spine revealed an osteolytic lesion in C5. Metastatic bone disease in the cervical spine was suspected, and the patient was referred to the Rokko Island Hospital. On physical examination, mild tenderness to palpation was noted over both cervical paravertebral muscles. Only mildly decreased touch sensations were present over the C7 dermatome on the left side. Other neurologic findings were normal.An anteroposterior radiograph of the cervical spine revealed a small round focal radiolucent lesion in the C5 vertebral body. Lateral radiographs revealed degenerative disk disease at the C5-C6 and C6-C7 levels, with narrowed disk spaces and deformed vertebral bodies (Fig. 1A). An oblique radiograph of the cervical spine clearly showed the radiolucent lesion in the C5 vertebral body (Fig. 1B). The patient subsequently underwent MR imaging, CT, and 99m Tc scintigraphy to evaluate the lesion. Sagittal T1-and T2-weighted MR images showed a small homogeneous hypointense lesion in the C5 vertebral body adjacent to the C5-C6 intervertebral disk (Fig. 1C). Axial T1-and T2-weighted MR images showed a hypointense lesion located in the posterolateral region of the C5 vertebral body to the right of the midline. The lesion was not enhanced on contrast-enhanced T1-weighted images (Fig. 1D). CT revealed a round, well-circumscribed lesion, 6 mm in diameter and with gas attenuation, in the C5 vertebral body (Fig. 1E). The CT attenuation at the epicenter of the lesion was -890 H, suggesting a collection of gas. No evidence was seen on CT or MR images of communication of the lesion with the disk space or the spinal canal. 99m Tc scintigraphy revealed increased isotope uptake in C5 and C6, which is concordant with degenerative disk disease. The imaging findings excluded metastatic bone disease of the cervical spine, and an intraosseous pneumatocyst was diagnosed.The patient was treated for the degenerative disk disease with antiinflammatory agents, which alleviated the symptoms. Radiographs obtained 10 weeks after the initial presentation revealed complete disappearance of the pneumatocyst in C5. Follow-up CT scans obtained 14 weeks after the initial presentation revealed a cystic structure in the C5 vertebral body (Fig. 1F). The ...

This study suggests that osteochondral graft stability may influence the histologic properties of the repaired cartilage. It is preferable to implant the slightly oversized graft into the cartilage lesion in autologous osteochondral transplantation to preserve the histologic properties of cartilage.

Meniscal cyst is a common condition and it has been suggested that the degeneration of the meniscus may be largely associated with the occurrence of a meniscal cyst. However, meniscal cysts forming after meniscal repair are exceedingly rare. Previous reports have suggested that meniscal cyst after meniscal repair can be attributed to the cystic degeneration of the meniscus and the thread used for the meniscal suture. In this report, the developmental mechanism of a meniscal cyst after meniscal repair suturing is discussed.

The purpose of this study was to evaluate the effect of the knee position at three different flexion angles in magnetic resonance (MR) delineation of the anterior cruciate ligament (ACL) in the knee and to determine the optimal knee position. Thirteen knees of normal volunteers were examined at 15 degrees, 30 degrees, and 45 degrees of flexion with a surface coil, and three sets of obtained oblique sagittal MR images were evaluated by four observers. MR images at 30 degrees of knee flexion most clearly delineate compared with those at 15 degrees and 45 degrees of knee flexion. We recommended examining the knee in 30 degrees of flexion.