This is common. If you make the diagnosis early, you need only drill the upper or lower end of a patient's femur, for which you will only need a limited incision. If you make the diagnosis late, osteomyelitis may have involved the entire shaft of the bone. If you approach it laterally, you can expose it from its greater trochanter to its lateral condyle. Cut straight through his vastus lateralis down to the bone. The head and neck of his femur are more difficult to reach. If osteomyelitis has involved the neck, which is partly inside the capsule of his hip joint, it will have also involved the head and his hip joint. This will need draining. You will find the anterior approach easiest for drilling the femoral neck (7.18). Refer him if you can.
Osteomyelitis of the femur commonly involves the hip joint, and occasionally the knee, but seldom both. When a child's knee is involved, his distal femoral epiphysis may slip. When this happens, the shaft of his femur usually slips anteriorly in front of the distal epiphysis[md]unlike trauma in which it slips posteriorly (79.16). Try to diagnose and treat him early; prevent further slipping by applying skin traction up to his mid thigh. You may need to manipulate him under anaesthesia.
Fig. 7-9 EXPOSING THE FEMUR. You can expose a patient's femur by cutting straight down to it along the lateral side of his thigh. A, prop him up on a sandbag. B, the middle third of his femur exposed. C, a cross-section of the middle of his thigh. D, a cross-section about 4 cm above his adductor tubercle. Kindly contributed by John Stewart.
THE SHAFT OF THE FEMUR Follow the general methods for osteomyelitis in Sections 7.4 to 7.6. Cross-match two units of blood for the patient[md]this can be a bloody operation, especially if you go too far posteriorly.
Lay him on his back with a sandbag under his hip on the infected side. Use a tourniquet when you operate on the middle or distal thirds of the bone.
Cut along the relevant part of the dotted line in A, Fig. 7- 9. This extends from just distal to his greater trochanter to just above his lateral femoral condyle. Cut through his skin, subcutaneous fat, and fascia lata. Then cut straight through his vastus lateralis, down to the lateral side of the shaft of his femur. There will be some bleeding, but much less than there would be if you cut posteriorly on to his linea aspera.
CAUTION ! (1) Take care to stay on the lateral surface of his femur. (2) Avoid his linea aspera, and the vessels which run close to it. (3) Remember that a small child does not have the blood volume of an adult, and that in him the loss of a given volume of blood is proportionately more serious (53-3).
If you are operating towards the distal end of a patient's femur: (1) Don't enter his knee joint or his suprapatellar bursa. (2) Stay strictly on the lateral side of his knee. (3) Don't go posteriorly, or you may injure his lateral popliteal nerve. (4) Don't go medially because you may injure the main vessels.
If he bleeds from the vessels of his linea aspera, catch them with a haemostat, and transfix them with a ligature on a curved needle. Pass the needle round under the haemostat and the vessels at least twice. Pull the ligatures tight as you release the haemostat. They are usually too deep into the wound to tie on the tip of a haemostat. If you cannot reach a bleeding vessel, pack the wound tightly, raise the foot of the table and wait for the bleeding to stop.
Postoperatively, apply skin traction. This will be easier than applying a medial plaster splint, which is the alternative. Later, put him in a hip spica or a plaster cylinder from his groin to his knee, give him crutches, and encourage weight- bearing.
Fig. 7-10 OSTEOMYELITIS OF THE TIBIA. A, and B, exposing the upper end of a patient's tibia. Note that the incision has been made over muscle on the lateral side. C, and D, exposing his lower tibia; again the incision has been made over muscle on the lateral side. E, F, and G, exposing the shaft of his tibia. The main part of the incision has been made on the lateral side and a flap reflected medially. H, and I, allowing the edges of the flap to fall into the wound to close it postoperatively.