Modified tetrachrome method for osteoid and defectively mineralized bone in paraffin sections.

A new modification of the tetrachrome method for bone osteoid in paraffin sections has been designed. The modified tetrachrome method suitable for routine use in any histology laboratory retains the simplicity of the original method and gives good results on the freshly fixed, decalcified, paraffin embedded material. Osteoid tissue is stained deep blue and normally mineralized bone is stained red. Defectively mineralized bone stains pale blue or pink and the cellular population is clearly identifiable. The ability to distinguish the osteoid tissue from mineralized bone and connective tissue and cartilage makes diagnosis of osteomalacia or osteoid producing tumors or assessment of ossification process straightforward, without the need for undecalcified sections. By displaying simultaneously irregularities in the mineralized matrix and morphology of bone cells, the method also permits the diagnosis of conditions recently described in patients with osteoporotic fractures, such as osteocytic degeneration and bone tissue defects.

Treatment of bone weakness in patients with femoral neck fracture by fluoride, calcium and vitamin D.

Twenty-three of 46 patients, aged 56 to 95 years, with fracture of the femoral neck (FNF) completed the first trial of 10 months treatment with oral sodium fluoride 60 mg and calcium 1800 mg on alternate days and 1 micrograms of vitamin D1 daily. Pre-treatment and post-treatment biopsy specimens and microradiographs of the iliac crest and metacarpal and spinal radiographs were evaluated together with biopsy material from seven untreated age-matched controls with FNF. In 17 patients the treatment improved the amount and quality of trabecular bone. Cortical thickness increased in nine patients and there were no losses of amount or mineralisation. The treatment was well tolerated by most patients and there were no major side-effects or signs of bone demineralisation. The study also revealed an unexpected rapid post-fracture deterioration of bone tissue in untreated FNF patients; thus there is an increased risk of further fractures which calls for the use of an effective treatment to increase bone mass.

Freezing of orthopaedic specimens before mechanical testing.

The effect of storage at sub-zero temperatures and subsequent thawing was investigated in dissected muscles, tendons, limbs and spines. Freezing caused a noticeable shortening of muscles which when thawed could easily be elongated; the same effects, though less pronounced, were observed with tendons. During freezing, myotomy or tenotomy led to the development of a striking deformity owing to unopposed shortening of the opposing muscles. After thawing, all frozen specimens containing muscles and joints showed an increased range of passive movements, easily demonstrable by mild tensile forces.

The use of Dexon as a replacement for the calcaneal tendon in sheep.

We have studied the use of filamentous polyglycolic acid (Dexon) for the induction of neotendon in the calcaneal tendon of sheep. Uniformly good results were obtained, with the formation of a thick neotendon. However, in a control group the power of spontaneous regeneration of the tendon was studied; it was found that, provided overlengthening of the gap was prevented, an equally good tendon resulted. It is concluded that this particular model is not an appropriate one for testing neotendon induction, despite its use for this purpose in the past. The favourable results of using filamentous polyglycolic acid as a tendon replacement suggest that it should be further investigated (in a more suitable model) since it may well have useful clinical applications.

Flexible carbon fibre in late ligamentous reconstruction for instability of the knee.

Sixty-three knees with chronic ligamentous instability treated with flexible carbon fibre are reviewed. Assessment was by pre-operative and postoperative grading of function in work and sport, together with a subjective evaluation of the result based on stability. Fifteen knees had collateral repairs, seven had cruciate repairs and 41 had combined collateral and cruciate repairs. Overall, 71% of knees showed improvement in function and 67% had good or excellent results subjectively. Clinical examination did not correlate well with the patient's evaluation of the result. Nineteen unselected cases with intra-articular (cruciate) carbon fibre had arthroscopies. Infiltration of collagen tissues into the cruciate replacement was a slower process than at the extra-articular (collateral) site. There was no clinical or macroscopic evidence of synovitis but microscopically there was evidence of synovial irritation.

Postmortem recognition and specimen fixation in early congenital and experimental limb deformities.

A method is recommended that facilitates the postmortem assessment of early stages of congenital or experimental paralytic and postural limb deformities, which otherwise are difficult to demonstrate on small specimens. One of the early signs detectable is change in the range of passive movements in the limb, and for its fine and objective assessment it is recommended that limb weight and gravity be used. Any disturbance of the original in vivo shape and position of the extremity during fixation of the postmortem specimen is prevented by suspension and free floating in the fixation fluid.

Changes in dimensions of large cancellous bone specimens during histological preparation as measured on slabs from human femoral heads.

Distortion of the dimensions of large cancellous bone specimens during all stages of histological processing and cutting of paraffin sections in various directions was measured on Xerograms taken from slabs and then sections from human femoral heads. Although some shrinkage in both width and height of the specimens occurred at every stage of the histological preparation, the main shrinkage (about 6%) occurred during the embedding process, and mainly in the cutting of the sections (10-27%, depending on the direction the knife was approaching the specimen). The shrinkage of cancellous bone tissue during histological preparation appears to be a constant factor, but its magnitude during the individual stages of the preparation can be predicted. For the quantitative measurements a comparison of two Xerograms--one taken from the original fresh bone slab and the other from the final stained section--would reveal the exact extent of the tissue shrinkage.

A technique for cutting slices from femoral heads and other awkwardly shaped bones.

For cutting thin, parallel slices from round and other awkwardly shaped bones, we have developed an useful aid by modifying the Microslice II cutting saw primarily designed for geological or metallurgical purposes. To ensure a good grip of the bone, the specimen is embedded in a bolus of wax in a cylindrical container and is advanced along the container by a screw plunger toward the cutting blade of the machine. It is thus possible to cut even from awkwardly shaped bones 2-30 mm thick parallel slices suitable for decalcified or undecalcified histological sections and also for radiodensitometry or quantitative microradiography.

A review of the morphology of Perthes' disease.

There are differences of opinion about the pathogenesis of Perthes' disease. All are agreed that it is due to ischaemia, but the cause of this and the size and number of infarctions are in dispute. Through the generosity of the contributors six whole femoral heads and core biopsies of five other cases have been studied radiographically and histologically. The findings ranged from an ischaemic arrest of ossification in the capital articular cartilage without infarction to multiple complete infarctions of the epiphysial bone. The ensuing reparative process contributes to the pathology, which is of a range to warrant grading or grouping.

Two phases of the bone mineral as revealed by the high resolution scanning electron microscope on ion-etched bone surfaces and as seen on surfaces untreated and chemically etched.

Recently reported uses of the technique of high resolution scanning microscopy of polished and Argon ion-etched bone surfaces have revealed that, at the ultrastructural level, the bone mineral is spatially arranged in a network of twisted, closely packed segments containing globular and cylindrical components. The ion-etching technique, which preferentially removes organic and less dense material from the bone surface, has been subsequently used by the present authors for detailed screening of a quantity of human cortical and trabecular bone of different age and maturity during which it has been found that apart from this "structured bone' containing twisted segments, the mineral is also organised in another regular form, the "lining bone', which has the appearance of solid, smooth and dense slabs or sheets lining active bone surfaces and bone cell lacunae and canaliculi. In the present study, in order to exclude the possibility that these two newly described phases of the bone mineral microskeleton are results of an etching artifact, their SEM appearance in 14 Argon ion-etched human bone specimens from individuals aged 11 post-natal days to 79 years was compared in various compartments to that seen on surfaces which were untreated, just polished or etched by hot NaOCl. The results have shown that both the structured and lining bone are genuine features since although the best results for their clear and reliable distinction were achieved by the ion-etching technique, these images could also be recognised on bone surfaces which were untreated or treated in a different way.

Epidemic of fractures during period of snow and ice.

During four days of snow and ice in which more than 70% of pavements in the Cardiff area were covered by slippery hard snow and ice the number of patients who attended the accident and emergency department at this hospital with fractured bones increased 2.85 times as compared with those who attended during four control days with comparable hours of sunshine and four control calendar days a year later. Fractures of the arm were increased 3.7 times and of the forearm and wrist 7.3 times. For a town population of one million people who may walk on untreated slippery and icy pavements this means that on average in a single day 74 more people than usual sustain a fracture unnecessarily. This traumatic epidemic has all the characteristics of a "major accident" and should be treated as such, since mobilisation of additional facilities, staff, and reserves might be necessary. Snow and ice injuries, however, differ from injuries sustained in a major accident in one important point: they may be predicted and prevented. The mass media should warn the population about the oncoming hazards and give practical advice on safer walking on slippery surfaces. The most important aspect of prevention, however, is instant cleaning of pavements around buildings, shops, and houses, especially in town centres and other areas busy with pedestrians.

The site dependence of the articular cartilage transplant reaction.

Allografts of immature joint cartilage from the knees of lambs were transferred heterotopically into an intramuscular site in animals which had been presensitised by two sets of skin grafts from the same donors. All of these grafts were found to be largely destroyed by the immune response as early as four weeks after transfer. Similar grafts transferred orthotopically into the knees of the recipients, on the other hand, were found to be thriving even after twelve weeks and evoked a minimal response. Heterotopic autografts also provoked a mild though non-specific inflammatory reaction which the orthotopic grafts did not. It is concluded that cartilage matrix is capable of protecting grafts to a remarkable degree even from a severe immunological assault but only when the nutrition is adequate. It is suggested that the conflicting results of similar previous experiments may be explained by variations in the nutritional state of the graft which may be affected by the technique of transplantation used.

Experimental production of local osteomalacia.

The newly deposited bone which was laid down on necrotic bone in the experimentally produced osteochondral chips in the knee joint of 16 sheep and rabbits remained unmineralized and undermineralized in which respect it resembled osteomalatic bone. Local factors which interfere with the mineralisation of a new covering bone should be considered in the pathogenesis of osteomalacia, in healing of aseptic bone necrosis and fractures, and incorporation and fate of bone transplants.

Biological reaction to carbon fiber implants: the formation and structure of a carbon-induced "neotendon".

In 43 young rabbits, the tendo Achilles and flexor digitorum longus tendon were excised and replaced by filamentous carbon fiber. Tendo-Achilles in controls was repaired by silk or nylon sutures or left without replacement. Concurrent excision of the posterior tibial nerve was performed in one group of the carbon-replacing tendo-Achilles operations. When fully functioning, carbon-induced "neotendon" rapidly developed from young fibroblastic tissue outgrowths of the loose mesenchymal tissue of the perineurium and adventitia of the blood vessels in the adjacent neurovascular bundle. Silk or nylon replacement of the excised Achilles tendon did not lead to successful production of a new substitute. Carbon fibers were unsatisfactory for replacement implants for the flexor digitorum longus tendons.