Abstract
THA after acetabular fracture presents unique technical challenges. These challenges include bone deformity, bone deficiency, sclerotic or dysvascular bone, non-united bony fragments, pelvic discontinuity, retained hardware, heterotopic ossification, previous incisions, and concerns regarding the sciatic nerve. Despite these challenges, with current treatment methods, a high degree of success can be achieved with modern technology.
Preoperative evaluation for infection - In previously operated acetabular fractures, infection is always a concern. Screening C-reactive protein and sedimentation rate may be performed. If a concern regarding infection is present, the hip may be aspirated; Incisions - In most cases, a previous incision may be utilised. If necessary, an incision may be extended or a new limb can be created and attention should be paid to maintaining optimal skin bridges.
In cases with a high degree of concern about infection, a staged procedure may be considered. However, in most cases, hardware removal can be done selectively at the time of THA surgery. Hardware that does not compromise placement of the THA may be left in place. Sometimes hardware can be cut off within the acetabulum to minimise exposure needs.
The reconstructive goal is to place the hip center as close as possible to normal hip center but also to gain good support of the socket on host bone. In most cases, both goals can be met. When necessary, some compromise in hip center of rotation may be considered to optimise implant stability on host bone. The principles of revision surgery are followed using uncemented acetabular components fixed with augmentation screws.
Most bone deficiencies may be managed with methods similar to revision hip surgery. However, in the acetabular fracture patient, usually the host femoral head is available and this can be used as bone graft, either in particulate or bulk form. Most cavitary deficiencies can be dealt with particulate bone graft. Some superolateral bone deficiencies from posterior wall fractures may be considered for bone grafting or augmentation techniques.
Nonunited fractures are not uncommon in these circumstances. Small wall nonunions may be managed as noted above for bone deficiency. If pelvic discontinuity is present, it is usually best treated by following the rules established for treatment of pelvic discontinuity with pelvic plating. Pelvic plating provides a reasonable likelihood of bone healing in these circumstances when combined with bone grafting techniques.
Heterotopic ossification is common in previously operated acetabular fractures. Removal of heterotopic bone at the time of surgery to gain hip motion is routine. Postoperative measures to reduce the likelihood of bone formation (that is either shielded radiation or use of a nonsteroid anti-inflammatory agent) may be strongly considered.
The sciatic nerve is at risk during these procedures. In many cases, avoiding the nerve and the region of the nerve is a reasonable approach. When a lot of work must be done on the posterior column, the surgeon needs to know exactly where the nerve is and in such cases the nerve may be exposed distally beneath the gluteus maximus tendon and followed proximally with careful and judicious dissection.
Results of total hip arthroplasty after acetabular fracture have varied in the past. More recent series have shown a high rate of acetabular fixation associated with uncemented hemispherical implants. Acetabular fracture patients are disproportionately young and active with unilateral hip disease and, therefore, bearing surfaces should be chosen accordingly.
