Aims

Rheumatoid arthritis (RA), which mainly results from fibroblast-like synoviocyte (FLS) dysfunction, is related to oxidative stress. Advanced oxidation protein products (AOPPs), which are proinflammatory mediators and a novel biomarker of oxidative stress, have been observed to accumulate significantly in the serum of RA patients. Here, we present the first investigation of the effects of AOPPs on RA-FLSs and the signalling pathway involved in AOPP-induced inflammatory responses and invasive behaviour.

Aims

This study aimed to determine the relationship between pedicle-lengthening distance and bulge-canal volume ratio in cases of lumbar spinal stenosis, to provide a theoretical basis for the extent of lengthening in pedicle-lengthening osteotomies.

Discogenic low back pain is a common cause of disability, but its pathogenesis is poorly understood. We collected 19 specimens of lumbar intervertebral discs from 17 patients with discogenic low back pain during posterior lumbar interbody fusion, 12 from physiologically ageing discs and ten from normal control discs. We investigated the histological features and assessed the immunoreactive activity of neurofilament (NF200) and neuropeptides such as substance P (SP) and vasoactive-intestinal peptide (VIP) in the nerve fibres.

The distinct histological characteristic of the painful disc was the formation of a zone of vascularised granulation tissue from the nucleus pulposus to the outer part of the annulus fibrosus along the edges of the fissures. SP-, NF- and VIP-immunoreactive nerve fibres in the painful discs were more extensive than in the control discs. Growth of nerves deep into the annulus fibrosus and nucleus pulposus was observed mainly along the zone of granulation tissue in the painful discs. This suggests that the zone of granulation tissue with extensive innervation along the tears in the posterior part of the painful disc may be responsible for causing the pain of discography and of discogenic low back pain.

We examined the pathogenesis of Schmorl’s nodes, correlating the histological findings from 12 lumbar vertebrae with the corresponding conventional radiographs, tomographs, MR images and CT scans. The last revealed round, often multiple cystic lesions with indistinct sclerotic margins beneath the cartilaginous endplate. The appearances are similar to the typical CT changes of osteonecrosis. Histological examination of en-bloc slices through Schmorl’s nodes gave clear evidence of subchondral osteonecrosis. Beneath the cartilage endplate, we found fibrosis within the marrow cavities with the disappearance of fat cells. Osteocytes within bone trabeculae were either dead or had disappeared. We suggest that Schmorl’s nodes are the end result of ischaemic necrosis beneath the cartilaginous endplate and that herniation into the body of the vertebra is secondary.

Materials & method: From July 1990 to July 1997, we reviewed 58 hips in 47 patients receiving primary cemented hip arthroplasty with porous-coated prosthesis. There were 31men and 16 women. The diagnoses included AVN of femoral head in 18, OA in 4, femoral neck fracture in 33 and RA in 3 patients. The prosthesis included PCA 17, Osteonics in 18, United in 21 and Richard in 1.

Initially, all the femoral canals were prepared with the routine cementless fixation technique modified by the author (rasp-ream-rasp technique). With insertion of the final-size rasp, reliable fixation was not obtained possibly due to poor bone quality or inherent canal geometry. To avoid fracture with insertion of the next-sized stem, bone cement was added as gap-filler to augment fixation of the final-sized stems.

Result: The average age of the patients at operation was 51.1 years old (range, 34 to 88). The mean follow-up was 5.8 years (range, 2 to 10). No patients were lost to follow-up. The mean Harris hip score at final F/U was 92 points. The X-rays taken postoperatively, 3months, 6months, 1 year, 2 years and the last F/U were checked carefully. Radiographically, there was no stem loosening, no measurable subsidence or demarcation line both in bone-cement and implant–cement interfaces. Even in the thinnest area of cement layer, no breakage or fracture was detected. Load transfer predominantly occurred at proximal 1/3 in 38 stems, at middle 1/3 in 20 stems (i.e. junction of porous coating and uncoated surface of the stem). No load transfer was noted at distal 1/3.

Conclusion: When reliable cementless stem fixation is not obtained intraoperatively, cement can be added to function as “gap-filler” for augmenting the initial fixation. The clinical and radiological result is quite favorable. Thin (< 2mm) cement mantle between bone and porous-coated stem will not result in early cement mantle break and implant failure.