Object In this paper the authors' goal was to identify histological and immunohistochemical differences between cervical disc herniation and spondylosis. Methods A total of 500 cervical intervertebral discs were excised from 364 patients: 198 patients with disc herniation and 166 patients with spondylosis. We examined en bloc samples of endplate-ligament-disc complexes. Types of herniation and graded degrees of disc degeneration on MR images were examined histologically and immunohistochemically. Results The herniated discs showed granulation tissue, newly developed blood vessels, and massive infiltration of CD68-positive macrophages, which surrounded the herniated tissue mainly in the ruptured outer layer of the anulus fibrosus. The vascular invasion was most significant in uncontained (extruded)-type herniated discs. Chondrocytes positive for matrix metalloproteinase (MMP)–3, tumor necrosis factor (TNF)–α, basic fibroblast growth factor (bFGF), and vascular endothelial growth factor (VEGF) were abundant in both herniated and spondylotic discs. Free nerve fibers, positive for nerve growth factor (NGF), neurofilament 68, growth-associated protein (GAP)-43, and substance P, were strongly apparent in and around the outer layer of uncontained (extruded)-type herniated discs, with enhanced expression of NGF. The authors observed that herniated discs showed more advanced degeneration in the outer layer of the anulus fibrosus around the granulation tissue than spondylotic discs. On the other hand, spondylotic discs showed more advanced degeneration in the cartilaginous endplate and inner layer of the anulus fibrosus than herniated discs. Spondylotic discs also had thicker bony endplates and expressed TNFα and MMP-3 more diffusely than herniated discs, especially in the inner layer of the anulus fibrosus. Conclusions The authors' results indicate that herniated and spondylotic intervertebral discs undergo different degenerative processes. It is likely that TNFα, MMP-3, bFGF, and VEGF expression is upregulated via the herniated mass in the herniated intervertebral discs, but by nutritional impairment in the spondylotic discs. Macrophage accumulation around newly formed blood vessels in the herniated disc tissues seemed to be regulated by MMP-3 and TNFα expression, and both herniated and spondylotic discs exhibited marked neoangiogenesis associated with increased bFGF and VEGF expression. Nerve fibers were associated with NGF overexpression in the outer layer of the anulus fibrosus as well as in endothelial cells of the small blood vessels.

We investigated the histological and immunohistochemical features of degenerative changes in the ligamentum flavum of the lumbar spine with calcium crystal deposition. We investigated degenerative changes in 270 ligamentum flavum specimens harvested from 198 patients who underwent decompressive surgeries for lumbar spinal canal stenosis. En bloc sections of the ligamentum flavum were examined histologically. We also examined immunoreactivity for transforming growth factor (TGF)-beta, vascular endothelial growth factor (VEGF), CD34, and CD68; immunoblot analysis for VEGF; and terminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate nick end-labeling (TUNEL) method. The ligamentum flavum showed fragmented and disorganized elastic fiber bundles with increased collagen fibrils in the matrix. Calcium deposition, which was identified as calcium pyrophosphate dihydrate crystals, was evident in 72 of 198 patients and in 99 of 270 samples, and was associated with appearance of hypertrophic chondrocytes and new blood vessel formation. Areas of calcium deposits were surrounded by abundant hypertrophic chondrocytes (with marked immunoreactivity to TGF-beta and VEGF) and a significant number of TUNEL-positive chondrocytes. Calcium crystal deposition in the lumbar ligamentum flavum progresses with reduction in elastic fibers and accumulation of collagen fibrils in the matrix as well as expansion of chondrometaplastic areas.

Using a nonlinear three-dimensional finite element analysis simulating loading conditions, we designed a new type of proximal-fitting, anterolaterally-flared, arc-deposit hydroxyapatite-coated anatomical femoral stem (FMS-anatomic stem; Japan Medical Materials, Osaka, Japan) for cementless total hip arthroplasty (THA) for Japanese patients with dysplastic hip osteoarthritis. The aim of the present study was to analyze the clinical and radiographic outcomes of the new stem. We reviewed 143 consecutive patients (164 hips; 13 men, 14 hips; 130 women, 150 hips; age at surgery, 56.6 +/- 7.6 years, mean +/- SD, range, 30-74) who underwent cementless THA using the FMS-anatomic stem at a single institution, with a follow-up period of 7.6 +/- 1.6 years (range, 5.3-11.0). Harris Hip score improved from 46.1 +/- 12.6 before surgery to 90.0 +/- 8.9 points post-THA. The 7.6-year survival rate of the stem was 99.0% after revision for aseptic loosening. Radiographs at follow-up confirmed the stability of the femoral stems within the femoral canal in all cases, with sufficient bone ingrowth. None of the patients had subsidence of the stem exceeding 2.0 mm within the femoral canal or changes in varus or valgus position of more than 2.0 degrees . The FMS-anatomic stem provided excellent results in patients with dysplastic hip osteoarthritis. Our analysis confirmed reduced radiolucency around the stem in Gruen zones, minimal subsidence, appropriate stress shielding, and promising medium-term stability within the femoral canal in our patients.

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