We reviewed 21 patients with Mason type-III fractures of the radial head treated by resection, evaluating the results at 16 to 30 years by a standard questionnaire and clinical and radiological examination of the elbow and wrist. Seventeen patients had an excellent result, three were good and one fair. Resection of the radial head is a satisfactory method of treatment of such fractures. Prosthetic replacement seems to be indicated only when there is valgus instability of the elbow.
The management of carpal dislocation after a late diagnosis is difficult. Open reduction is the usual treatment but collapse of the carpus may be hard to overcome without extensive dissection and consequent damage to the blood supply, ligaments and articular cartilage. A technique of distraction by an external fixator followed by semi-closed reduction is described and its successful use is reported in two cases.
Ischaemia resulting from increased joint pressure may play a role in the pathogenesis of necrosis of the femoral head epiphysis. We studied the effect of temporary vascular occlusion on this epiphysis in young rabbits. Occlusion for six hours resulted in necrosis of trabecular bone and of intertrabecular marrow and vascular tissue, later followed by revascularisation and repair, as has been demonstrated previously. In contrast, raised intra-articular pressure lasting for only two hours resulted in a more complex picture: trabecular osteocytes were dead, whereas the bone-forming marrow was shown by fluorochrome labelling to remain viable, and to form appositional repair bone throughout the epiphysis. We concluded that transient vascular occlusion may cause the death of trabeculae despite intact perfusion of the bone. This type of change may be important in the pathogenesis of Perthes' disease.
The pathogenesis of Perthes' disease has been related to increased intra-articular pressure secondary to a joint effusion. The pressure within the hip in different positions was measured in eight children with transient synovitis and four with the synovial stage of Perthes' disease. In the position of comfort for the hip this pressure was always less than the arteriolar blood pressure and in a supine position it did not exceed the systolic blood pressure. However, in extension with medial rotation the intra-articular pressure always became several times the systolic blood pressure. This high pressure was also recorded in the stable lateral position which occurs normally during sleep. It is concluded that in the presence of a synovial effusion in the hip, a position of extension and medial rotation causes an increase in intra-articular pressure which may compromise the blood supply to the capital epiphysis of the femur.
A diastasis between the femoral head and the acetabulum can be achieved for a short while by the application of manual traction on the lower extremity. The intra-articular low-pressure area can be visualised radiographically and is known as a "vacuum phenomenon". The resulting arthrogram clearly outlines the shape, thickness and extent of the cartilage. In the presence of an effusion the diastasis occurs without a vacuum phenomenon. This simple, non-invasive and inoffensive method of traction radiography will not only show abnormalities of the cartilage but also demonstrate the presence or absence of an effusion of the hip.
