what-when-how
In Depth Tutorials and Information
PERI
OPERATIVE CONSIDERAT
IONS
of the greater trochanter may be stable and, if minimally
displaced, may be treated nonoperatively (
Figure 49.2
).
The most typical deformity in patients with OI is a varus
femur, which often makes the placement of a straight
The operating table must be well padded, and great
care must be taken when transferring, positioning and
preparing the patient to avoid fracturing noninvolved
bones.
Table 49.1
summarizes difficulties in placing hip
and knee replacements in patients with OI.
Hip Replacement
Exposure can be difficult in patients with OI. If the
hip is very stiff, the use of an extended trochanteric
osteotomy may need to be considered just to obtain
access. Another tactic is to cut the femoral neck
in situ
and to remove it. Care must also be taken during any
intraoperative maneuvers such as dislocating or relocat-
ing the hip. Excessive force can easily lead to additional
fracture of the femur.
The most common difficulty in acetabular recon-
struction is protrusio of the acetabulum.
6
In this situa-
tion, the surgeon should be prepared to use bone graft
behind the acetabular component and to use additional
screw fixation, which will allow him or her to recreate
the true hip center. An intraoperative radiograph to
show cup placement is always worthwhile in this situ-
ation. Periprosthetic acetabular fracture, ordinarily rare,
is more common in patients with OI. Because the bone
is brittle, cup impaction can lead to posterior column
fracture. The surgeon should be prepared in this situa-
tion for plate and screw fixation of the fracture so that a
stable cup can be placed (
Figure 49.1
).
FIGURE 49.1
An intraoperative acetabular fracture occurred in this
patient with OI. A posterior plate was used to stabilize the acetabulum
to allow the placement of an uncemented cup with multiple screws.
Femoral Component
Femoral component placement can be made diffi-
cult by several factors, including the presence of defor-
mity, the presence of hardware and poor bone quality.
Even in patients with mild OI, insertional fracture of
the femur may occur. Fractures of the calcar should be
treated with cabling of the femur, and consideration
should be given for a fully coated prosthesis. Fractures
TABLE 49.1
difficulties in Joint Replacement in Patients with OI
Pre-existing hardware
Deformity
Proximal femoral bowing for femoral stem insertion
Distal femoral or tibial bowing for total knee insertion
Acetabular protrusio
Small bone diameter
Small bone size
Bleeding diathesis
Bone fragility leading to intraoperative or postoperative fracture
Ligamentous laxity leading to difficulty in balancing a knee
replacement
FIGURE 49.2
Anteroposterior radiograph of a patient with mild
OI who sustained an intraoperative greater trochanteric fracture. It
was treated nonoperatively, and it healed uneventfully.
