Previous Acetabular Fracture
David G. Lewallen
Posttraumatic degenerative changes of the hip are common after acetabular fracture.
Fracture sequelae can include residual deformity due to malreduction and/or malunion.
Nonunion or resorption of original fracture fragments can result in major segmental or cavitary defects.
Retained hardware from prior fracture fixation can impinge on the joint or the acetabular preparation and may require removal in part (preferred) or less often in total.
Partial hardware removal can be facilitated by metal cutting tools.
Extensive hardware removal can place soft tissue and neurovascular structures at risk and is usually only indicated in the case of deep infection when a 2-stage reconstruction is planned.
Heterotopic bone formation can be a challenge at the time of arthroplasty and can complicate postoperative course.
Obtaining durable long-term fixation can be challenging, and consequently extra socket fixation often is needed.
Sterile Instruments and Implants
Standard hip arthroplasty instruments and retractors.
Extra-large or deep retractors for obese patients.
Proper screw drivers for retained hardware removal or “universal” screw driver sets with multiple heads can be very helpful.
Carbide cutting tools or high-speed burrs for sectioning metal screws or plates.
Sterile ultrasound gel to trap metal debris when burring.
Multihole highly porous acetabular components are preferred to allow 3 to 6 screws for secure cup fixation and encourage reliable bone ingrowth.
Large-diameter heads (36 mm or greater) to reduce dislocation risk.
Optional sciatic nerve monitoring if there is prior sciatic nerve dysfunction or complete removal of posterior column plate or posteriorly located heterotopic bone is required.
A second surgical assistant many times is helpful.
The posterolateral approach is commonly used, especially if a prior Kocher-type posterior incision was used for internal fixation of the acetabular fracture originally and especially when complete removal of posterior column hardware is required.
The direct lateral (and less often the direct anterior) approach can also be used, and both are preferred by some surgeons for some or even most cases. Partial hardware removal may be employed to manage any encroaching screws or hardware, generally using intra-acetabular access to those portions of the hardware encroaching on the joint or encountered during acetabular preparation.
Rarely trochanteric osteotomy or supplemental ilioinguinal approaches may be required when truly extensile exposure is needed for removal of large masses of heterotopic bone or for complete removal of extensive hardware present on the inner table or going well up onto the iliac wing posteriorly.
Complete hardware removal is not routine and is generally reserved for cases with associated deep infection.
Careful preoperative planning is important to anticipate special hardware removal needs as discussed earlier or to anticipate deformity or bone deficiency that might compromise implant fixation leading to cup loosening or cup malposition and associated hip instability.
An anteroposterior (AP) radiograph of the pelvis and AP and cross-table lateral radiographs of the affected hip are required views (Figure 14.1A-C).
Obturator and iliac oblique x-rays (Judet views) can also be very helpful in assessing bone defects and hardware location in some cases.
Selective use of axial imaging with computed tomography or magnetic resonance imaging can provide additional help in visualizing the 3-dimensional relationships around the acetabulum of bone defects and hardware, or heterotopic bone location (Figure 14.2).