If the traumas treated at Ishiuchi Clinic of Showa University during the past 31 years from 1957 to 1988 are classified by topical site and type, the traumas in the knee and ankle joints are seen in many cases, occupying totally 53% of the total traumas. Compared with these, the traumas in the hip joint are relatively rare, and particularly, the cases of traumatic dislocation of the hip joint are extremely rare articular traumas. The subject cases were 6 males and 5 females.
The traumatic mechanisms have been elucidated, and concurrently, super selective angiography was performed on the medial circumflex arteries in 8 cases to determine angiographically the time when loading began.
There are many cases whose posterior dislocations were presumably caused by a mechanism that, while the tibia is fixed by skiing boots in a position including forward in angles slightly wider than 90°, flexion and rotary strengths applied to the hip joint are much strong at the skier's position with extended knee joint because the safety binding does not come loose at the fall of the body forward.
The superior retinacular arteries are said to be very important remification of the medial circumflex femoral artery which supplies 2/3-3/4 of blood stream to the outside of the loaded epiphysial region. What are presumed as the causes for the ineffective and defective angiograms are (1) compression by hematoma, (2) extended SRA and (3) rupture of SRA. The time of loading to begin was found as 2 months in the case with favorable angiograms of SRA and 4 months in the cases with ineffective or defective angiogram.

1) The objectives of author's present study were 42, 245 patients with ratio of males to females of 7 to 3 in 44, 327 affected locations, covering the period of 23 years from the December of 1956 to the end of March of 1979.
2) All the injuries thus treated can be classified into 18, 815 (42.5%) of sprains, 11, 838 (26.7 %) of fractures, 9, 650 (21.8%) of lacerations, 2, 812 (6.4%) of contusions, 752 (1.7%) of dislocations and 460 (1.0%) of others.
3) Looking from auther's statistical study of the ski injuries in the past 23 years, the development of the ski equipments have largely effected on the ski injuries.
4) The lacerations on the head, face and arm are increased when the safety bindings have come into wide use. So, we expect the effect of the ski-stopper replacing the strap, in order to decrease the lacerations.
5) Injuries of the ankle have been decreased because of the plastic ski boots. Especially, “the ski fractures”, or, the abducted and external rotated fractures of the lateral malleolus are decreased remarkably.
6) The knee sprains, or, the ligamentous strains of medial colateral ligament of knee joint have been increased, because the stiff and high backed plastic ski boots have come into wide use.
7) Fractures of the lower legs and boot top fractures have been increased, according the development of the ski boots, such as from the leather boots to buckled boots to plastic boots.

This time the statistics for injuries and disorders due to sports in the five-year period up to 1985 were taken, evaluated and compared with those of the last five-year period. The following results were obtained :
1. There were 1, 300 cases of injuries and disorders due to sports in the five-year period up to 1985, which was 4.4% of the total number of outpatients in the department of orthopaedics.
2. Sex : There were more male patients, but the rate of female patients has been increasing lately.
3. Age : Patients in their teens or twenties accounted for about 70%.
4. Body Side : There was no significant difference between incidence of injury on the right side of body or the left, but cases of injuries on both sides have been increasing recently.
5. Kind of Sport : The largest number of trauma were due to skiing, although the number of trauma resulting from playing tennis has been high in the past five-years of investigation.
6. Time of Injury ; Most patients were injured during practice, followed by recreation and game.
7. Position of Truma : Most cases were injuries to their knee joints from skiing.

This time the statistics for injuries and disorders due to sports in the five-year period up to 1985 were taken, evaluated and compared with those of the last five-year period. The following results were obtained :
1. There were 1, 300 cases of injuries and disorders due to sports in the five-year period up to 1985, which was 4.4% of the total number of outpatients in the department of orthopaedics.
2. Sex : There were more male patients, but the rate of female patients has been increasing lately.
3. Age : Patients in their teens or twenties accounted for about 70%.
4. Body Side : There was no significant difference between incidence of injury on the right side of body or the left, but cases of injuries on both sides have been increasing recently.
5. Kind of Sport : The largest number of trauma were due to skiing, although the number of trauma resulting from playing tennis has been high in the past five-years of investigation.
6. Time of Injury ; Most patients were injured during practice, followed by recreation and game.
7. Position of Truma : Most cases were injuries to their knee joints from skiing.