We measured on the radiographs of 100 knees the length of the patellar ligament and the anterior cruciate ligament, and the distance between the tibial tubercle and the femoral insertion of the anterior cruciate. The length of the patellar ligament was always greater than that of the anterior cruciate ligament, but shorter than the distance between the tibial tubercle and the femoral insertion of the anterior cruciate by a mean of 14.2 mm (3 to 22). We conclude that anatomical, isometric replacement of the anterior cruciate is possible using a free graft, but not by the technique of retaining the tibial attachment originally described by Jones (1970).

Most patients with dominantly inherited osteogenesis imperfecta have blue sclerae and relatively mild symptoms. However, in a small group of families the patients have normal sclerae and this disorder has been classified as Type 4 osteogenesis imperfecta. This paper reports the clinical and radiographical features of 48 patients from 16 families with Type 4 osteogenesis imperfecta and compares the findings with those of the classical disorder with blue sclerae (Type 1 osteogenesis imperfecta). The two types are similar in usually causing a mild disease but with a wide range of severity, and in both types the rate of fracture declines in adolescence. There are, however, some significant differences apart from the colour of the sclerae. In Type 4 the first fracture more commonly occurs at birth, dentinogenesis imperfecta is more frequent than in Type 1 and bruising and nose-bleeds are less common. As in Type 1, the radiographic appearances of the bones may be normal. It is important that Type 4 osteogenesis imperfecta should be recognised because of the need for competent genetic counselling, because the management may be different from that appropriate for Type 1 and because it may be mistaken for idiopathic juvenile osteoporosis or child abuse.