Predictors of poor outcome after both column acetabular fractures: a 30-year retrospective cohort study

Abstract

Background and purpose: Acetabular fractures are often combined with associated injuries to the hip joint. Some of these associated injuries seem to be responsible for poor long-term results and these injuries seem to affect the outcome independent of the quality of the acetabular reduction. The aim of our study was to analyze the outcome of both column acetabular fractures and the influence of osseous cofactors such as initial fracture displacement, hip dislocation, femoral head lesions and injuries of the acetabular joint surface.

Methods: A retrospective cohort study in patients with both column acetabular fractures treated over a 30 year period was performed. Patients with a follow-up of more than two years were invited for a clinical and radiological examination. Displacement was analyzed on initial and postoperative radiographs. Contusion and impaction of the femoral head was grouped. Injuries of the acetabular joint surface consisting of impaction, contusion and comminution were recorded. The Merle d'Aubigné Score was documented and radiographs were analysed for arthritis (Helfet classification), femoral head avascular necrosis (Ficat/Arlet classification) and heterotopic ossifications (Brooker classification).

Results: 115 patients were included in the follow up examination. Anatomic reduction (malreduction ≤ 1mm) was associated with a significantly better clinical outcome than nonanatomical reduction (p = 0.001). Initial displacement of more than 10mm (p = 0.031) and initial intraarticular fragments (p = 0.041) were associated with worse outcome. Other associated injuries, such as the presence of a femoral head dislocation, femoral head injuries and injuries to the acetabular joint surface showed no significant difference in outcome individually, but in fractures with more than two associated local injuries the risk for joint degeneration was significant higher (p < 0.001) than in cases with less than two of them.In the subgroup of anatomically reconstructed fractures no significant influence of the analyzed cofactors could be observed.

Conclusion: Anatomical reduction appears to be an important parameter for a good clinical outcome in patients with both column acetabular fractures. Additional fracture characteristics such as the initial displacement and intraarticular fragments seem to influence the results. Patients should also be advised that both column acetabular fractures with more than two additional associated factors have a significantly higher risk of joint degeneration.

Figure 1

Correlation between radiological outcome and MAS. The percentage share of patients with good radiological outcome is shown with the light grey columns. The percentage share of patients with radiological joint degeneration (Helfet, Brooker, Ficat/Arlet stadium 3 and 4) is shown with the dark grey columns. MAS groups were defined as group 1 (no functional limitations (18 points), group 2 (slight limitations (15–17 points)), group 3 (moderate limitations (13–14 points)) and group 4 (severe limitations (<13 points)).

Figure 2

The percentage of radiological joint failure increases in case of increasing number of associated cofactors (hip dislocation, intraarticular fragments, femoral head or acetabular joint surface impaction, initial displacement >10mm). ** p = 0.001.

Figure 3

a) This is a x-ray of a 48 year old motor cyclist, who suffered an accident with a both column acetabular fracture accompanied by a pelvic ring injury. Due to a massive soft tissue involvement of the pelvis and prolonged wound healing, an isolated ilio-inguinal approach was applied to reduce and stabilize the fracture. Therefore a nonanatomical reduction had to be accepted. b) X-ray 4 months after surgery. The combination of great initial displacement and nonanatomical reduction led to a rapid joint degeneration with poor clinical function.