Total hip arthroplasty (THA) is one of the preferable solutions for regaining ambulatory activity for patients with end-stage osteoarthritis, and the procedure is well developed technically and large numbers of patients benefit from THA worldwide. However, despite the improvements in implant designs and surgical techniques, revision rates remain high, and the number of revisions is expected to increase in the future as a result of the increase in the volume of primary THA and the increase in the proportion of younger, more active patients who are likely to survive longer than their prosthetic implants. In revision THA, associated loss of bone stock in the acetabulum presents one of the major challenges. The aim of the present study was to analyze the clinical and radiographic outcomes and Kaplan-Meier survivorship of patients underwent revision surgeries of the acetabular cup sustaining aseptic loosening. We reviewed consecutive 101 patients (120 hips; 10 men 11 hips; 91 women 109 hips; age at surgery, 66 years, range, 45–85) who underwent acetabular component revision surgery, at a follow-up period of 14.6 years (range, 10–30). For the evaluation of the state of the acebtabulum, acetabular bony defects were classified according to the classification of the AAOS based on the intraoperative findings as follows; type I [segmental deficiencies] in 24 hips, type II [cavity deficiency] in 48 hips, type III [combined deficiency] in 46, and type IV [pelvic discontinuity] in 2. Basically, we used the implant for acetabular revision surgery that cement or cementless cups were for the AAOS type I acetabular defects, cementless cup, or cemented cup with reinforcement device were for type II, cemented cup with reinforcement device were for type III. Follow-up examination revealed that Harris Hip score improved from 42.5±7.8 points before surgery to 76±16.2 points (p<0.05). The survival rates of the acetabular revision surgery with cemented cups, cementless cups, and cemented cups with reinforcement devices were 65.1%, 72.8%, and 79.8%, respectively, however, there was no significant differences between the groups. There were nine cases, which failed in the early stage in the groups of cementless cups and cemented cups with reinforcement devices, because of the instability of the cementless cups or breakage of reinforcement plates caused by inadequate bone grafting. We conclude that the usage of the cementless cups for type I and II acetabular bony defects, and the cemented cups with reinforcement devices for type III bony defects will demonstrate durable long-term fixation in case of adequate contact between acetabular components and host-bone with restoration of bone stock by impaction bone grafting.

To investigate the histological findings for a herniated cervical intervertebral disc that produces a high intensity signal on MR images.

Fifty-five herniated cervical intervertebral discs harvested from 49 patients were histologically and immunohistochemically examined. Herniated cervical intervertebral discs with a high intensity signal on axial T2 MR images were classified as a globular, linear, or mosaic type. The specimens were embedded with paraffin using standard procedures. Serial 4 μm thick cryostat sagittal sections were prepared for HE, toluidine blue, PAS, and Elastica van Gieson staining as well as immunohistochemical study. The monoclonal antibodies used were specific for human CD68, IL-1β, and TNF-α.

Preoperative axial T2 MR images indicated that 3 discs had no high intensity signal and 52 discs had a high intensity signal; 22 discs were globular, 20 were linear, and 10 were mosaic. Histopathologically, high intensity signal areas in globular discs consisted of nucleus pulposus surrounded by macrophages. These macrophages and the chondrocytes around them expressed IL-1β and TNF-α. Almost all of the patients with a globular disc, had had severe radicular pain. For the linear disc patients, the fissure was observed consistent with the high intensity signal. A substance that would produce positive results for PAS staining was rarely observed.

The current histological study suggests that a globular type of disc with a high intensity signal on an axial T2 MR image consisted of a nucleus pulposus. Results demonstrated that, in these herniated discs, infiltrated macrophages and chondrocytes expressed inflammatory cytokines, and these reactions were associated with radicular pain. In contrast, linear and mosaic discs showed no obvious substance corresponding with the high-intensity zone, but the fissure was observed. It appears that a high-intensity zone for a linear or mosaic type of disc suggested of a fluid-filled area and/or mucoid fluid.