This Knee Joint Simulator serves to investigate the tribological behaviour of total knee prostheses. In order to register the most important influences upon it, it is necessary to derive first of all the requirements upon the simulation of the various movements and loads from the physiological knee joint. These and some other requirements which are of a common sort, serve as the basis of the construction, the function of which is to be described in the following passage.

We compared two groups of patients with whplash injury. The first group of 17 patients received a life annuity or a cash settlement, whereas the second group, comprised of 84 people, received no compensation at all. This comparison revealed some considerable differences. However, with regard to statistically significant factors, the 2 groups differ only in neurological symptoms, giddiness, and degenerative changes revealed by X-ray. In the first group, 11 patients who received compensation showed two of the statistically significant factors; 5 patients showed one factor; and 1 showed none. The criteria which govern the granting of compensation are being discussed in detail on the basis of our own cases and the literature. It is an exception when permanent damage due to whiplash is accepted. In individual cases, however, continuous complaints and objective findings years after the trauma are justification for a moderate compensation.

1. The articular surfaces of the femoral head of rats have been studied by scanning electron microscopy after in vitro treatment with hyaluronidase. 2. The cartilage surface has been digested mildly by the buffer medium (control). 3. The matrix of the cartilage has selectively been removed by the hyaluronidase. 4. Chondrocytes have been seen on the surface after treatment with hyaluronidase for a longer period. 5. We discuss the result of enzymatic digestion.

By means of electromyographic evaluation we investigated the function of the rectus femoris, the vastus medialis, the tibialis anterior and the triceps muscle. The effects of immobilisation in above or below knee PoP were investigated with view to the muscular activity in walking and the effect of the immobilization in isometric exercises. The results are discussed. The vastus medialis can only be activated very poorly in a PoP and is not inervated at all during gait. The functional activity of the triceps is reduced markedly in either above or below knee PoP. In knee movement this muscle starts to be activated only over 90 degrees of flexion. The results suggest that an above knee PoP is sufficient to immobilise defects of the quadriceps and its tendon. Defects of the triceps and its tendon seem not necessarily to request an above knee PoP for immobilization. This case has however the advantage to decrease the danger of unexpected knee movements followed by a reflectoric muscle contraction. Its force could be greater than the stability of the repaired tendon.

Residual valgus deformity and overgrowth was found in 4 children out of 6 with proximal tibial metaphyseal fractures. Primary reduction of this minimally displaced fracture under general anaesthesia is advised. In case of an irreducable fracture open revision is suggested. In case of an established valgus of more then 20 degrees a tibial wedge osteotomy is necessary. Recurrence of the deformity is very common especially in young children.

Tear fractures of the os calcis are rare. If they do occur, the cause may be osteoporosis. This could be proved in an experimental study rupturing the achilles tendon. Usually, the tendon is the weakest link in the muscle-tendon-bone-chain. In case of osteoporosis, the insertion of the tendon is more vulnerable.

31 cases of infected pseudarthrosis of the femur were re-osteosynthesized with the interlocking nail. Bony consolidation was obtained in 26 patients, in all cases the chronic osteomyelitic infection subsided with removal of the nail. Pseudarthrosis persisted in 3 cases, after removal of the nail the patients could walk with a walking splint. In one of this group bony consolidation was obtained after repeated interlocking nailing. Persisting pseudarthrosis and infection was the indication for amputation in 2 cases.

The treatment of osteogenesis imperfecta with magnesium is theoreticaly sound, but usually works in a few individuals. There are greater expectations with calcitonin, which reduces the overall osteolysis. The treatment of fractures should, whenever possible, be concervative. Internal fixation by plates is not indicated, because the plate should span from metaphysis to metyphysis, which leads to a softeming of the underlying cortex. Because of the weak bone, srews do not hold well. For operative treatment of the lower limb, the Küntscher nail is the fixation of choice, as well as for treatment of deformity by multiple fragmentation. Rapidly progressive scoliosis should be treated operatively from 9 years of age on.

Temperature measurements are reported effected by aid of thermocouples enclosed in tubules in TEP-implantations of the hip. Two techniques were employed: the first using as acrylic bone cement Palacos or Sulfix-6 without concomitant cooling, the second Palacos after precooling of the femur with crushed ice/water mixtures. The first method yielded, at the acrylic bone cement/bone interface, temperatures above the coagulation point of the protein (56 degrees C). The novel technique of implantation is described, i.e. the cooling of the bone with ice-water prior to the cement implantation. This technique provides a means of restricting the average temperature at the aforesaid interface to 45 degrees C.

The literature regarding bone level concentrations of different antimicrobial agents is reviewed. The investigation using Azlocillin shows a sufficiantly high concentration in human bone to include this agent among other semisynthetic penicillins.

Bone transplantations are made often in the treatment of benign bone tumours or tumour like affections. Especially at the appropriate infantile illness the use of an autologous transplant may prove impossible. Homologous and heterologous osseous transplants are largely unsuitable, because of the induction of immunological reactions. So called syngenesioplastic transplants let expect a tolerance of the recipient organism. This is a report of the results of clinical, radiological and especially immunological follow-up-examinations of 11 patients treated from August 1974 to October 1976 with syngenesioplastic spongiosa transplantation.

Corrective osteotomy is indicated in young manual workers with significant malalignment after fracture of the distal radius without associated degenerative changes in the wrist joint. Chronic pain, limited motion and impaired power can be avoided and the cosmetic appearance of the hand improved, by restoration of the functional anatomy of the wrist. The operation consists of an opening-wedge osteotomy at the fracture site, sometimes combined with resection of the distal ulna. The approach may be dorsal or volar. A small iliac cortico-cancellous bone graft is inserted at the osteotomy site. Fixation is by an AO-small fragment-T-plate allowing early functional after-treatment.

From 1917--1976 68 pelvis fractures of children (up to 14 years) were hospitalized at the department of Surgery, University of Göttingen. About 75% were traffic accidents. The lesions prefer the iliosacral joints, symphysis and the biogenic connections. Experimental compressions confirm the clinical fractures. The controls show sufficient subjective results. Because of pelvis dislocation and scoliosis controls are necessary.

The problems of the treatment of femoral neck fractures in young patients are discussed on 22 cases as well as the operative technique, post-operative treatment, late complications and their treatment. We feel that femoral neck fractures in children and young ones should be treated operatively. The three flanged nail should be used for internal fixation, giving a better fixation than K-wires. We have not seen any damage caused by the crossing of the epiphyseal plate with a nail or K-wires. Postoperatively the patient should walk non weight bearing on the fractured hip for 9 months, especially in transcervical fractures. The danger of aseptic necrosis of the femoral head is clearly diminished by this precaution. The late results of femoral neck fractures in juveniles are clearly worse than in children. The femoral neck fracture of the young is to be treated as an emergency. If the therapy is too late or not adequate the consequences for the hip joints of the juveniles can be drastic.