Removal of osteochondral fragment

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 supine or lateral.

For this procedure the following approaches may be used:

• Anterior approach
• Anterolateral approach
• Lateral approach via trochanteric flip

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.

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.

After surgical stabilization, the construct should be sufficiently robust to allow protected weight bearing. Smaller children may not be able to comply with this and may need immobilization.

See the additional material on postoperative infection.

Forces through the hip are less with toe-touch weight bearing than with non-weight bearing. Therefore, toe-touch is normally recommended for initial mobilization. This needs to be taught to children by a physiotherapist.

Range-of-movement exercises should start in the immediate postoperative period to prevent stiffness. Surgeons should indicate if any extremes of movement are forbidden.

Having started with toe-touch weight bearing, children progress to partial weight bearing and then to full weight bearing according to their age and the predicted rate of healing of their fracture.
Even older adolescents should be fully weight bearing without aids at three months.

Swimming can be allowed as soon as partial weight bearing is permitted.
Contact sports should be avoided for at least six months.

X-rays are generally taken immediately after the surgery and at 6 and 12 weeks.

Implants that cross the physis should be removed if there is significant growth remaining. The fracture should be healed and consolidated prior to removal (see Healing times).

Implants in young children should always be removed to prevent them from being covered by bony overgrowth.

Implant removal is not compulsory in adolescents.