Bertil Widenfalk

The Early Development of Articular Cartilage After Perichondrial Grafting

In an experimental series of 39 rabbits the articular cartilage of the femur condyles was resected and the defect covered by a perichondrial graft from rib cartilage. The graft was fixed to the bony surface by using Tisseal (Immuno AG) and the joint was immobilized for two weeks. Beginning 24 hours postoperatively the neochondrogenesis from the perichondrial graft was analyzed histologically, sacrificing the rabbits with 48 hours interval. The fibrin glue acted as a visible border line between the bony surface and the graft. No vascular proliferations penetrated the fibrin glue, indicating that the perichondrial graft must be nourished by the synovial fluid only. The neochondrogenesis was found to occur in the median and fibrous layer of the graft.

The Effect of Growth Factors and Synovial Fluid on Chondrogenesis in Perichondrium

Reconstruction of cartilage with perichondrium depends on the chondrogenic property of the perichondrial fibrocytes. The present investigation concerns the conditions for the differentiation of fibrocytes into chondrocytes both in vivo and in vitro. For the in vivo studies specimens of rib and auricular perichondrium from adult rabbits were wrapped round silicon rods which were enclosed in dialysis bags. One was placed in the suprapatellar pouch of the knee joint and one was placed intraperitoneally in each rabbit. After two months the bags were extracted, the perichondrium prepared for microscopic examination, and the chondrogenesis evaluated. In vitro the perichondrium was divided into small pieces and incubated with tissue culture medium. The medium was supplemented with fetal calf serum, together with epidermal growth factor, platelet derived growth factor, synovial fluid, or with human serum albumin (control group). After three weeks the explants were prepared for microscopy. Chondrogenesis was judged by the degree of cellular enlargement, capsule formation, deposition of matrix, and activation of the outer fibrocytic layer. In vivo, good cartilage development was found in all specimens placed in the knee joint but, in those placed intraperitoneally, little if any chondrogenesis was seen. In vitro profound differentiation occurred in all cultures supplemented with epidermal growth factor and platelet derived growth factor. An equivalent differentiation was found in perichondrium that had been incubated with synovial fluid. We conclude that the differentiation of perichondrial fibrocytes is initiated in vitro by growth factors. In addition, we have shown that synovial fluid contains factors that promote and enhance the development of cartilage from perichondrium.

Origin of sympathetic and sensory innervation of the knee joint

SummaryThe origin of sympathetic and sensory innervation of the knee joint was investigated by the intra-axonal transport method. After injection of horseradish peroxidase (HRP) or horseradish peroxidase conjugated to wheat germ agglutinin (WGA-HRP) into the knee joint unilaterally in adult rats, labelled neurons were found ipsilaterally both in sympathetic and dorsal root ganglia at the lower thoracic and lumbosacral levels. A maximum of 1500 and 1000 peroxidase-positive cells were observed in the sympathetic and dorsal root ganglia, respectively; in the former they were mainly located at the levels of L2–L4, and in the latter mainly at L3–L5. The functional implications of the above observations are discussed in relation to pain mechanisms in joints and to the earlier hypothesis that a nervous component might be involved in the pathogenesis of chronic joint inflammation.

Perichondrial arthroplasty using fibrin glue and early mobilization. An experimental study.

An experimental study was performed in rabbits to find out whether fibrin glue, used to simplify the procedure for graft fixation in perichondrial arthroplasty, would also allow earlier mobilization of the grafted joint, thereby reducing the risk for postoperative stiffness of the joint. The results indicate the possibility of reducing the time used for postoperative fixation from three weeks originally to one week, and still achieve the same results regarding graft healing and cartilage regeneration. Immediate post-operative mobilization caused loosening of the graft and endangered the results.

CHARACTERISATION OF CELLS IN REGENERATING CARTILAGE FROM AUTOTRANSPLANTED PERICHONDRIUM. IMMUNOHISTOCHEMICAL EXPRESSION OF SMOOTH-MUSCLE ACTIN, DESMIN, VIMENTIN, AND Ki-67

Autotransplanted perichondrium from rib and ear sutured to the knee joints of 26 rabbits has been examined with immunohistochemistry and shows certain structural, functional, and proliferative characteristics of regenerating cartilage. Cryostat sections have been examined for the expression of smooth-muscle actin (SMA), desmin, vimentin, and Ki-67. In this rabbit model of perichondrial grafting SMA staining showed vivid vessel regeneration, particularly in the proliferating stage about two to three weeks after grafting, and no vessels in more mature parts one month or more after transplantation. Desmin staining showed expression and distribution similar to SMA. Vimentin staining shows the cytoskeleton of regenerating cartilaginous tissue and makes cellular borders apparent. Immunohistochemical expression of Ki-67 is constantly negative in perichondrial tissue from rib and ear before transplantation, clearly positive in the proliferative stage, but there is no expression in maturing cartilage. The study also shows that all human antibodies used are applicable in a rabbit model.

Expression of Platelet-Derived Growth Factor β Receptor in Chondrogenesis of Perichondrial Transplants

An experimental study was done in two rabbits to establish whether the early stages of cartilage generation involves stimulation via the platelet-derived growth factor beta receptor (PDGFR-beta). Rib perichondrium was dissected off and transplanted to the knee joint. The perichondrial grafts were removed for microscopic investigation at day 0 and day 6 and kept frozen until analysed by immunohistochemistry and in situ hybridisation for the presence of PDGF beta receptor protein and mRNA, respectively. Samples from day 0 showed sparse cells with a positive immunohistochemical reaction. In samples from day 6 there were signs of perichondrial proliferation and chondroid maturation and a more widespread immunohistochemical staining reaction could be seen mainly on proliferating perichondrial cells, but also on some chondrocytes. In situ hybridisation confirmed the expression of PDGF beta receptor mRNA in the same areas of serial sections. These findings may indicate that PDGF beta receptor activity is part of the early response after autotransplantation of perichondrium.

Treatment of a large aneurysmal bone cyst in a 15-year-old boy using a corticospongial bone graft and a 12-year follow-up after operation

Abstract We report the case of a 15-year-old boy with a large aneurysmal bone cyst in the third metacarpal, which was operated on radically with excision of the bone and grafting from the distal radius. At 12-year follow-up the patient had good cosmetic results and a perfectly functioning hand.

Multiple brown tumours of the upper extremity in a patient with secondary hyperparathyroidism as a result of chronic renal failure

Abstract A man with chronic renal failure was referred to the hand clinic because of massive osteolytic tumours in his right arm. Secondary hyperparathyroidism and brown tumours were suggested, and he was treated by subtotal parathyroidectomy. Rapid reduction of the vast tumours was noted postoperatively.

Involvement of Connections Between the Brainstem and the Sympathetic Ganglia in the Pathogenesis of Rheumatoid Arthritis: An anatomical study in rats

The central connections between the superior cervical ganglion of the sympathetic trunk and the brainstem were investigated in five rats by trans-synaptic transport of lectin-conjugated horse-radish peroxidase. After injection of this tracer into the superior cervical ganglion, labelled cells were seen in both the ventral and dorsal parts of the medullary reticular formation. The neurons were found mainly on the same side as the injection site. Besides retrograde labelling, there was an antegrade termination within the nucleus of the solitary tract. We hypothesise that a nervous mechanism is involved in the pathogenesis of rheumatoid arthritis, and that a supraspinal input to the sympathetic ganglia might influence this mechanism.

Ligament Reconstruction using Free Perichondrial Graft

In five adult rabbits the medial collateral ligament of one knee joint was replaced by a free perichondrial graft from a rib. When tested after 2 to 5 months the joints were stable in all cases. Histological sections showed a picture of mixed cartilaginous and ligamentous tissue in all specimens. These promising results may open new fields for the use of perichondrium as a ligament substitute for ligament--for example, in the wrist.