重组骨形态发生蛋白-2结合软骨下钻孔治疗犬关节软骨全层缺损的实验研究

目的 研究重组骨形态发生蛋白-2(rhBMP-2)结合软骨下骨钻孔治疗犬关节软骨全层缺损的可行性，为临床应用提供实验依据。方法 依照软骨缺损处理方法的不同将64侧股骨髁随机均分为4组：①结合组：软骨下骨钻孔 胶原海绵吸附rhBMP-2充填软骨缺损；②BMP组：胶原海绵吸附rhBMP-2充填软骨缺损；③钻孔组：单纯软骨下骨钻孔；④对照组：不作处理或单纯用胶原海绵填塞。术后2、4、8、12周取材观察其大体、光镜、透射电镜、免疫组织化学情况。结果 除对照组仅有纤维组织修复外，其余3组均有不同程度的软骨修复，但结合组的修复在组织细胞形态、超微结构、Ⅱ型胶原含量等方面均明显优于其他两组。结论rhBMP-2结合软骨下骨钻孔能有效修复犬膝关节软骨的全层缺损，该技术可行，有望在临床应用。     

Morphomechanics of the humero-ulnar joint: II. Concave incongruity determines the distribution of load and subchondral mineralization

Background: A deeper joint socket (concave incongruity) is found at most angles of flexion of the humero-ulnar joint and maintained over a wide range of physiological loading. It is, however, unclear how far this incongruity affects the distribution of load and subchondral mineralization of this joint as compared with a congruous configuration. Methods: Two nonlinear, axisymmetrical finite element models with two cartilage layers were constructed, one congruous and one incongruous, with a joint space of realistic magnitude. The distribution of subchondral mineralization was determined by computed tomography osteoabsorptiometry in the same six specimens that were investigated in the first part of the study, and compared with the biomechanical data obtained there and the predictions of the models. Results: In the congruous case, the center of the socket is highly loaded, whereas the periphery does not experience mechanical stimulation. A central bone density maximum is predicted. With concave incongruity the position of the contact areas shifts from the joint margin towards the center as the load increases, and the peak stresses are considerably lower. A bicentric ventro-dorsal distribution pattern of subchondral mineralization is predicted, and this is actually found in the six specimens. Conclusions: Concave incongruity is shown to determine load transmission and subchondral mineralization of the humero-ulnar joint. It is suggested that this shape leads to a more even distribution of stress, provides intermittent stimulation of the cartilaginous tissue, and has beneficial effects on the metabolism, nutrition, and lubrication of the articular cartilage during cyclic loading. © 1995 Wiley-Liss, Inc.     

Changes in mean trabecular orientation in the medial condyle of the proximal tibia in osteoarthritis

In osteoarthritis of the knee, degenerative changes occur in the articular cartilage and underlying subchondral bone, particularly of the medial tibial condyle. Cancellous bone sclerosis that accompanies osteoarthritis is not only the result of an increase in bone volume fraction but also a change in trabecular structure. In a comparison with agematched controls (n=4), osteoarthritis (n=11) demonstrated a significant (P0.05) increase in bone volume fraction and trabecular thickness. Overal trabecular orientation in the osteoarthritic group was more vertical or perpendicular to the articular surface than the control group (P0.05) especially in the trabeculae of the cancellous bone layer closest to the articular surface. These alterations in trabecular bone structure could have significant consequences for the mechanical properties of osteoarthritic bone.     

Articular degeneration after subchondral cementation for giant cell tumors at the knee

PurposeTo quantify joint degeneration and the clinical outcome after curettage and cementation in subchondral giant cell tumors of the bone (GCTB) at the knee.MethodsWe conducted a retrospective analysis of 14 consecutive patients (seven female, seven male) with a mean age of 34 years (range 19–51) who underwent curettage and subchondral cementation for a biopsy-confirmed GCTB at the distal femur or the proximal tibia between August 2001 and August 2017, with a mean follow-up period of 54.6 months (range 16.1–156 months). The Whole-Organ Magnetic Resonance Imaging Score (WORMS), Kellgren-Lawrence (KL) classification, and Musculo-Skeletal Tumor Society (MSTS) score were assessed.ResultsRadiological degeneration progressed from preoperative to the latest follow-up, with a median WORMS from 2.0 to 4.0 (p = 0.006); meanwhile, the median KL score remained at 0 (p = 0.102). Progressive degeneration (WORMS) tended to be associated with the proximity of the tumor to the articular cartilage (mean 1.57 mm; range 0–12 mm) (p = 0.085). The most common degenerative findings were cartilage lesions (n = 11), synovitis (n = 5), and osteophytes (n = 4). Mean MSTS score increased from 23.1 (preoperatively) to 28.3 at the latest follow-up (p < 0.01).Seven patients (50%) were treated for a local recurrence, with six revision surgeries performed. Removal of the cement spacer and filling of the cavity with a cancellous autograft was performed in seven patients. Conversion to a total knee arthroplasty was performed in one patient for local tumor control.ConclusionsCementation following the curettage of GCTB around the knee is associated with slight degeneration at medium-term follow-up and leads to a significant reduction in pain. Removal of the cement and reconstruction with an autograft may be beneficial in the long term.     

Conditions Simulating Primary Bone Neoplasms

A number of nonneoplastic conditions can mimic tumors of bone. Some of the more common mimics of primary bone tumors include infectious, inflammatory, periosteal, and degenerative joint disease-associated lesions that produce tumorlike bone surface-based or intraosseous lesions. This article considers a spectrum of reactive and nonreactive processes including stress fracture, subchondral cysts, osteonecrosis, heterotopic ossification, osteomyelitis, sarcoidosis, and amyloidoma that can present in such a way that they are mistaken for a tumor arising primary in bone.     

Bi-layer collagen/microporous electrospun nanofiber scaffold improves the osteochondral regeneration

An optimal scaffold is crucial for osteochondral regeneration. Collagen and electrospun nanofibers have been demonstrated to facilitate cartilage and bone regeneration, respectively. However, the effect of combining collagen and electrospun nanofibers on osteochondral regeneration has yet to be evaluated. Here, we report that the combination of collagen and electrospun poly-l-lactic acid nanofibers synergistically promotes osteochondral regeneration. We first fabricated bi-layer microporous scaffold with collagen and electrospun poly-l-lactic acid nanofibers (COL-nanofiber). Mesenchymal stem cells were cultured on the bi-layer scaffold and their adhesion, proliferation and differentiation were examined. Moreover, osteochondral defects were created in rabbits and implanted with COL-nanofiber scaffold. Cartilage and subchondral bone regeneration were evaluated at 6 and 12 weeks after surgery. Compared with COL scaffold, cells on COL-nanofiber scaffold exhibited more robust osteogenic differentiation, indicated by higher expression levels of OCN and runx2 genes as well as the accumulation of calcium nodules. Furthermore, implantation of COL-nanofiber scaffold seeded with cells induced more rapid subchondral bone emergence, and better cartilage formation, which led to better functional repair of osteochondral defects as manifested by histological staining, biomechanical test and micro-computed tomography data. Our study underscores the potential of using the bi-layer microporous COL-nanofiber scaffold for the treatment of deep osteochondral defects.     

Effect of different doses of transforming growth factor-β1 on cartilage and subchondral bone in osteoarthritic temporomandibular joints

Transforming growth factor-beta (TGF-β) plays an important part in the repair of cartilage in osteoarthritis. It has been hypothesised that intra-articular injection of TGF-β₁ promotes repair of cartilage and protects the subchondral bone from damage in osteoarthritic temporomandibular joints (TMJs). We made bilateral partial perforations of the disc to induce osteoarthritic joints in 36 rabbits. TGF-β₁ 20, 40, or 80 ng were injected into the right joint, and vehicle alone was injected into the left joint. Four additional animals were used as normal controls. Microcomputed tomography was used to quantify the three-dimensional microarchitecture of subchondral bone, followed by assessment of the proteoglycan content. All joints treated with TGF-β₁ were covered by a layer of well-organised fibrocartilage, and had increased proteoglycan content and normal microarchitectural properties, whereas the joint treated by vehicle alone had typical osteoarthritis-related degradation of cartilage and sclerosis of subchondral bone. These results suggested that TGF-β₁ is an effective way of treating osteoarthritis of the TMJ.