Inge Reimann

A Histological Demonstration of Nerves in Subchondral Bone

Several different staining procedures were carried out on decalcified histological sections from human femoral heads to demonstrate the nerves in subchondral bone. The femoral heads were obtained at surgery from patients with fractures of the femoral neck or osteoarthritic hip joints. The Bodian technique was found to be the most suitable. Serial sections were used in order to disclose the various sources of error. It was not possible to demonstrate nerves in the bone matrix, but they were easily seen in the subchondral bone marrow, after related to the vessels. A comparison of the fracture and osteoarthritic cases revealed an obvious difference; more nerves were seen in osteoarthritis. The method described is considered suitable for further study of the nerves in osteoarthritic femoral heads.

Quantitative histologic analyses of articular cartilage and subchondral bone from osteoarthritic and normal human hips

Twelve femoral heads (two normal, four after fracture and six osteo-arthritic) were obtained at surgery or autopsy. Circumferential slices were obtained and five separate areas were analyzed in each for ash content; histological-histochemical grading of the severity of the cartilage changes; and quantitative morphometric analyses to establish the percentage of trabecular area, osteoblastic area and osteoclastic area. Analyses were performed to compare weight-bearing and non-weight-bearing areas of the femoral heads and to determine correlations between the bony and cartilaginous alterations. The data obtained showed wide variations in all parameters in the osteoarthritic specimens but consistently more marked cartilage and bony changes in the weight-bearing areas. Bone structures and metabolic parameters were distinctly increased for the osteoarthrities, differing significantly from both normal and fracture control groups. The bony change correlated directly with the severity of the cartilage lesions, as determined by the histological-histochemical grade.

The synovial membrane in human coxathrosis: light and electron microscopic studies.

Changes of the synovium are in integral part of osteoarthritis. Most authors regard these changes as secondary to cartilage degeneration. However, synovitis is a very early feature in osteoarthritis, and increased knowledge of changes in the chemical composition of the synovia focused our attention on the histologic characteristics of osteoarthritic synovium. Light and electron microscopic studies of the synovial membrane from patients with osteoarthritis and rheumatoid arthritis of the hip joints were performed. Two distinct types of osteoarthritic synovitis were observed: an early proliferative from characterized by venous stasis with edema, free erythrocytes and hemosiderine deposits in the interstitial tissue, that suggested increased capillary permeability. In the late form, fibrous synovitis, the microscopic picture was dominated by dense fibrous tissue. Synovium from rheumatoid arthritis showed the same vascular changes as in osteoarthritis. In addition, the histologic picture was characterized by severe inflammatory changes. In osteoarthritis the signs of inflammation were moderate or absent. The development from proliferative into fibrous synovitis is probably the result of long-standing chronic venous insufficiency. The essential feature of osteoarthritic proliferative synovitis--venous stasis with increased capillary permeability--correlates well with most of the known changes in the composition of the synovial fluid.In patients operated on for painful coxarthrosis, the synovium of the hip joint is always visibly abnormal. Most authors seem to agree with Lloyd-RobertsI2 that the changes in the synovium are secondary to cartilage destruction and result from displacement of joint detritus into the synovium. The changes in osteoarthritic synovium have been judged histologically to be nonspecific. I n Clinical experience suggests, however, that synovitis is a very early feature of osteoarthritis and that the synovial fluid-a dialysate of blood plasma from the synovial capillaries to which hyaluronate, synthesized by synovial lining cells, is added-is the vehicle that supplies oxygen and nutrition to the cartilage. Recent findings, such as a low oxygen tension in osteoarthritic synovia,I4 changes in the protein pattern that suggest an increased perme-

Experimental Osteoarthritis in the Rabbit: A Study of 133Xenon Washout Rates from the Synovial Cavity

Synovial perfusion in 6 rabbit knees, with experimentally induced osteoarthritis (joint instability), was studied by recording the initial 133Xe washout rates from the joint space. The unstable osteoarthritic knee was compared with the contralateral sham operated control knee at intervals of 6 to 96 weeks postoperatively. Within the first half year the ratio between the 133Xe washout rates in the osteoarthritic and control joints was significantly increased. These findings were supported by the increased blood flow to the joint region, visualized by scintigraphy of osteoarthritic rabbits given 99mTc-microspheres intracardially. However, methodological sources of error do not allow any conclusions regarding the much less increased 133Xe washout rates found in advanced osteoarthritis. The initially increased synovial blood flow coincided with the existence of joint effusion and the early development of osteophytes, all conditions supposed to be a consequence of posttraumatic synovitis. Attention is drawn to these pathogenic phenomena in studies dealing with the initial changes in experimental models of osteoarthritis and to a possible etiological significance.

Demonstration of Boundary Lubrication by Synovial Fluid

An account is given of an oscillatory rotating friction measurement apparatus which can be used for demonstration of boundary lubrication by synovial fluid when rubber and glass are employed as rubbing surfaces. A technical description of the apparatus is given. The greatest importance is placed on getting the apparatus to demonstrate reproducible results when saline and normal bovine synovial fluid are used as lubricant. The greatest variations are caused by differences in the cleaning of the rubber and in its tension. On the basis of bovine synovial fluid from ten different hock joints investigations were made of individual variations and changes occurring during storage at 4 degrees C. The individual variations were found to be of no importance; a decrease in the lubricating effect was observed only after storage for two months. Addition of trypsin confirmed that boundary lubrication by synovial fluid can be related to the protein component. The conclusion is that the apparatus is considered suitable for clinical investigations of boundary lubrication in connection with different joint diseases.

DEPRESSIVE EFFECTS OF ACRYLIC CEMENT COMPONENTS ON BONE METABOLISM Isotope Release and Phosphatase Production Studied in Vitro

In vitro methyl methacrylate bone cement components were found to depress the release of radioactive calcium and proline as well as the activity of both alkaline and acid phosphatases. These effects were dose dependent and reached levels observed for dead bone. These observations may reflect part of the pathogenesis of loosening of joint replacements involving the use of bone cement.

Repair of three-month-old experimental meniscal lesions in rabbits

Repair of three-month-old longitudinal meniscal lesions in the central avascular portion of the knee joint was investigated in 18 rabbits. Three months after a longitudinal incision was made in the avascular portion of the meniscus, no healing was observed. At that time a full-thickness radial cut from the lesion to the joint capsule, without using synovial flaps or implants, was performed in ten of the 18 rabbits. Three months later, nine of the ten menisci had healed mainly with cartilaginous tissue, although the repaired areas were different from the normal fibrocartilage both histologically and at gross inspection. Synovitis with hyperplasia of the lining cells, which was present in all cases at the time of repair, may play an important role in the healing process.

The Pathology of Congenital Metatarsus Varus: A Post-mortem Study of a Newborn Infant

A case of congenital metatarsus varus from an autopsy of a newborn infant was explored. Contracture of the anterior tibialis muscle was present as well as alterations in size and shape of the first cuneiform bone. Furthermore, subluxations in the fore- and midfoot were observed, especially round the first cuneiform bone. It is concluded that congenital metatarsus varus may be classified as a subluxation followed by secondary bone changes and contractures in the soft tissues.

A HISTOCHEMICAL STUDY OF ALKALINE AND ACID PHOSPHATASE ACTIVITY IN OSTEOARTHRITIC SYNOVIAL MEMBRANE

In order to determine the localization and activity of alkaline and acid phosphatase in the synovial membrane of osteoarthritic hip joints, enzymo-histochemical analyses were performed using Burstones and Barka & Andersons methods. Frozen sections of synovial biopsy material from 12 osteoarthritic and 6 control hip joints were studied. Alkaline phosphatase was found located in fibroblasts below the lining cells and in capillaries and precapillary arterioles. Acid phosphatase was seen in the lysosomes in the lining cells. Semiquantitative evaluation by means of initial time determination showed significantly greater activity in osteoarthritic synovia than in the control group. Whilst the increased activity of lysosomal enzymes is presumably implicated in the joint cartilage damage seen in osteoarthritis, the significance of elevated alkaline phosphatase levels is not yet clear.

Congenital Metatarsus Varus: On the Advantages of Early Treatment

Among 212 infants with congenital metatarsus varus 84 (39.6 per cent) of the infants were treated. Only the treated group is considered in the analysis. Daily manipulative therapy was given followed by fixation in elastic bandage or splint. The manipulations aimed at correcting the adduction of the fore part of the foot, as well as the increased valgus of the heel. In 68 infants treatment was instituted before one year of age. The results were good in 65 of these patients and correspondingly good results were obtained in 15 out of 16 patients treated at more than one year of age. Subluxation in the fore- and midfoot and bony incongruity present at birth are offered as a possible explanation for lack of spontaneous recovery before weightbearing as well as the occurrence of resistant cases. Spontaneous improvement may take place during childhood and may be explained by the influence of the position of the heel during weightbearing.