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WSV18-0228
ORTHOPEDIC SURGERY
FEMORAL HEAD EXCISION: A PRACTICAL APPROACH TO SIMPLIFYING THIS SURGERY AND IMPROVING OUTCOMES
M. Glyde1
1BVSc MACVSc MVS HDipUTL Diplomate ECVS, College of Veterinary Medicine. Murdoch University
Learning Objectives
At the end of this session you will be able to:
· Identify the surgical landmarks for correct excision of the femoral head and neck
· Position the limb correctly to ensure the correct plane of excision
The dog is positioned in lateral recumbency with the affected leg uppermost. The procedure is simplified if the leg is free-draped so that the stifle and hock joints are within the sterile field and can be manipulated during the surgery by a scrubbed-in assistant.
An incision is made immediately cranial to the greater trochanter. The incision is centered at the level of the trochanter and extends distally about 1/5 of the femoral length and the same amount proximally.
The subcutaneous tissue is dissected on the same line. The fascia between the biceps femoris caudally and the tensor fascia cranially is incised along the same line from the trochanter distally. The cranial edge of the superficial gluteal muscle is incised and separated from the tensor fascia muscle.
The division between the middle gluteal dorsally and the tensor fascia lata muscle ventrally is developed. The line of this division is the ventral edge of the ilium – this will be at right angles to the midpoint of your initial incision.
If you are struggling to find the division between the middle gluteal and the tensor fascia lata due to fat or hemorrhage or edema from trauma palpate the wing of the ilium and draw a line from the ventral edge of the ilial wing to the greater trochanter. This is the line that the ventral edge of the middle gluteal muscle lies on.
The middle gluteal is retracted dorsally to expose the deep gluteal. Both insert on the greater trochanter. The middle gluteal has a muscular insertion onto the greater trochanter while the deep gluteal has a white tendinous insertion. The middle gluteal is much thicker than the deep gluteal.
Blunt dissect between the middle and deep gluteal muscles just cranial to the greater trochanter. Use a Langenbeck or similar blade retractor to retract the deep gluteal dorsally to visualize the tendon of the deep gluteal.
A partial tenotomy of the deep gluteal tendon is then made. The deep gluteal tendon is cut transversely at right angles to the direction of the tendon for 1⁄2-2/3 of its width about 5mm from its insertion on the greater trochanter.
A cut is then made from the dorsal edge of the transverse tenotomy in a cranial direction running parallel with the muscle fibers. This will also be the line of incision along the femoral neck into the joint capsule.
The deep surface of the deep gluteal muscle is loosely attached to the joint capsule of the hip. The deep surface of the deep gluteal muscle is blunt dissected away from the joint capsule.
The Langenbeck retractor is now placed more deeply to retract both the middle and deep gluteal muscles.
You should now be looking at the joint capsule of the hip joint and be able to see the thin capsularis coxae muscle running over the joint capsule.
This is the point where people often get “lost” in the approach. You are looking at the joint capsule covering the femoral head and neck however it is not as easy to see as it appears in some of the surgical approaches texts.
Externally rotate the leg and palpate the femoral head. You can feel a curved “groove” which is the dorsal acetabular rim.
Now incise the capsule directly along the head and neck. There are 3 ways you can identify the line for this incision.
The first and easiest way is that the capsular incision is on the same line as the longitudinal incision through the deep gluteal tendon.
The second is that it is at the most dorsal part of the femoral head and neck. The third is that it runs on the same line as the thin capsularis coxae muscle. Use a scalpel blade and make this capsular incision cutting down on the femoral head and neck.
Continue the capsular incision along the femoral head and neck laterally along the cranial surface of the proximal femur through the origin of the vastus muscles.
Combine sharp (scalpel) and blunt (periosteal elevator) dissection to reflect the joint capsule and associated vastus muscles from the cranial aspect of the proximal femur. The capsular tissue will not elevate and will need sharp dissection with a scalpel blade to elevate it. The vastus muscle will elevate easily with a periosteal elevator if you push at 45 degrees to the bone surface and find the subperiosteal plane.
Reflect the vastus muscles from the cranial surface sufficiently so that you will be able to eventually make the femoral neck cut on a line connecting the medial
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