Open capsulotomy vs arthroscopy
Small osteochondral fragments, as determined by MRI, can be removed either through a capsulotomy, or arthroscopically.
The indication for arthroscopic removal depends on the surgeon's skill with hip arthroscopy.
The advantages of hip arthroscopy are:
- Minimally invasive capsulotomy
- Enhanced visualization of the joint
- Visualization of the osteochondral defect in the head
The limitation of an arthroscopic approach is the size of the fragment. Larger fragments will require conversion to an open approach.
Note: Flake fractures are mostly the result of traumatic hip dislocation.
Incongruency after dislocation is very often overlooked on conventional x-rays.
Gentle distraction of the joint may facilitate irrigation and visualization.
For arthroscopic removal, a fracture table is always used.
Note: For a detailed description, the reader is referred to the corresponding textbooks, or literature.
In an open procedure, "free-hand" distraction, or distraction using the fracture traction table is at the discretion of the surgeon.
The advantage of free-hand distraction is the ability to rotate the femoral head. However, the amount of distraction possible is less than when using a traction table.
Depending on the approach, the patient may be placed either
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For this procedure the following approaches may be used:
In some specific cases (eg, large fragments, or a bigger defect on the femoral head),
surgical hip dislocation
can become necessary for removal of the fragment. Surgical hip dislocation also facilitates reattachment of the fragment, or corrective osteotomy to reorientate the intact part of the femoral head into a good loading position.
Removal of fragments
After the capsulotomy, the joint is irrigated and large fragments are picked out using forceps, pituitary rongeurs etc.
All fragments identified on the preoperative MRI should be accounted for.
Subluxation by traction, with internal and external rotation, is useful for visualization of the joint and to free trapped fragments.
Irrigation of the subluxed joint will often flush out hidden fragments.
For larger fragments, complete hip dislocation may be necessary.
Image intensification should be used to confirm concentric reduction.
History: A 7-year-old boy sustained a ski injury while jumping over a bump and landing directly on the hip.
The right hip was dislocated.
After reduction, the joint space was asymmetric and a fragment was seen in the joint space.
This is an absolute indication for removal of the fragment.