[Pathology and pathophysiology] The tuberculosis of the greater trochanter of the femur can be divided into two types: bony and bursal. Among the bone tuberculosis, the central type is the most common. The pus from the bony type tuberculosis can penetrate the greater trochanter to the nearby bursa and cause secondary bursal tuberculosis of the greater trochanter, and conversely, bursal tuberculosis of the greater trochanter can also erode the greater trochanter bone and cause secondary bone tuberculosis. Whether the tuberculosis is of the bony or bursal type, the resulting pus often flows laterally, anteriorly, and posteriorly to the greater trochanter; occasionally it flows upward along the gluteus medius, gluteus minimus, or downward between the broad fascia and lateral femoral muscle due to gravity. Sometimes it can also reach the vicinity of the knee joint and even penetrate the knee capsule, causing knee tuberculosis, and the abscess breaks down to form a sinus tract. Long-term abscesses may become calcified. Tuberculosis of the greater trochanter can sometimes reach the hip joint. The route of invasion can be through the femoral neck or through the femoral head. If it occurs in children, the tissue near the lesion can be congested, stimulating the upper femoral epiphysis and accelerating its development, resulting in an increase in the stem angle of the femoral neck up to 150°, making the affected side 1 to 2 cm longer than the healthy side. [Diagnostic points] Clinical manifestations 1. Symptoms and signs Early symptoms are not obvious. Pain, swelling and pressure pain are limited to the local area, and limping and hip function limitation are not obvious. Therefore, it is often diagnosed until an abscess appears. The abscess breaks down and forms a sinus tract. 2.X-ray performance Bone type tuberculosis X-ray film can see typical osteochondral tuberculosis changes; bursal type tuberculosis can see soft tissue swelling and local osteoporosis. Abscesses are often calcified in the late stage. Differential diagnosis The diagnosis of osteoid tuberculosis is generally easy and should be differentiated from rheumatoid bursitis, giant cell tumor of bone, bone metastases, and chronic bone abscess. The diagnosis of bursal tuberculosis is more difficult, and it should be differentiated from non-specific bursitis and lipoma. Treatment overview】 Since there is little chance for tuberculosis of the greater trochanter to invade the hip joint, non-surgical treatment can be used for cases without obvious dead bone. Abscesses can be drained by puncture and local injection of anti-tuberculosis drugs. If treatment is ineffective, lesion debridement is used. The site is superficial, with no significant tissue, and is easily revealed surgically. However, because the lesion shown on X-ray is smaller than the actual lesion, the lesion should be fully exposed and completely removed, otherwise it may recur. If the abscess is far from the greater trochanter, another incision can be made to cross-cut the broad fascia and cut the iliotibial bundle, pulling the broad fascia tensor muscle forward and the gluteus maximus muscle backward to reveal the greater trochanter. To further expose the lesion at the top of the greater trochanter, the gluteus medius and minimus muscles are sometimes cut at 1 cm from the stop. Similarly, to reveal the lesion at the lower part of the greater trochanter, the superior lateral femoral muscle is sometimes dissected downward. Once the greater trochanter is fully exposed, the lesion is removed, and care is taken not to miss the abscesses in the interstitial spaces of the muscles, and the entire bursa should be removed as much as possible for bursal tuberculosis. Bony tuberculosis should be removed by enlarging the bone cavity and scraping the diseased bone and dead bone. In cases of localized bone defects with large cavities and no mixed infection, ipsilateral iliac bone graft can be used to fill the bone cavity. For those with mixed infections, broad fascial tensor fasciae with tipped muscle flaps can be implanted. In order to prevent the accumulation of blood and fluid in the postoperative wound, the wound can be bandaged with pressure with an “8” bandage. The patient should be bedridden for 3~4 weeks after surgery, and if there is much bone destruction, the time of getting up and weight-bearing should be postponed.