Indications and Planning

The majority of acetabular fractures should be treated operatively as this leads to the best long-term results.¹ In some fracture types, conservative treatment is suitable if certain parameters are considered.

In this chapter, general indications for operative and conservative treatment of acetabular fractures are discussed. For detailed decision making in specific fracture types, refer to the fracture type chapters.

The decision regarding operative or conservative treatment and the possibility and the expected result of closed reduction techniques have to be considered. Anatomical reduction by closed techniques is often hard to achieve, although improvement of position of the articular fragments can be achieved in most cases.²^,³ Closed reduction can lead to an optimized result by ligamentotaxis only for associated both-column fractures.⁴

The main problem in closed reduction techniques is the rotation control of the fragments, especially in T-type fractures and associated both-column fractures because, in these fracture types, winglike displacement of the column fragments can lead to central dislocation.⁴

Traction is also considered insufficient as, irrespective of its duration, re-dislocation often occurs after traction is released.⁵

In general, the personality of the fracture should be considered.⁶^,⁷ The following factors should be analyzed: expectations and functional needs of the patient, physical and psychological status of the patient, personal experience of the surgeon in acetabular fracture surgery, and availability of perisurgical requirements, such as, adequate instruments, blood bank, intensive care unit, etc.

This chapter focuses on indications for conservative treatment, as indications for operative treatment are presented in detail in the respective chapters.

6.2 Indications for Conservative Treatment

Typical indications for nonoperative treatment include⁴:

Undisplaced or minimally displaced fractures
Fractures with displacement in joint areas considered as of no prognostic relevance
Secondary congruency in associated both column fractures
Local soft tissue compromise
Medical contraindications
Osteoporosis

Additional indications for nonoperative treatment are a stable hip joint, sufficient congruency of the hip joint, and minor involvement of the weight-bearing area of the acetabular dome.¹^,⁵^,⁸^,⁹^,¹⁰^,¹¹^,¹² The decision for nonoperative treatment in undisplaced fractures should not be made based on an anteroposterior (AP) pelvic X-ray alone. At least Judet views should be part of the evaluation, and a computed tomography (CT) scan with multiplanar reconstructions for detailed assessment of the fracture morphology and the displacement is recommended (▶ Fig. 6.1). In addition, marginal impaction zones and intraarticular fragments have to be ruled out.

Fig. 6.1 Minimally displaced anterior column fracture. CT scan with multiplanar reconstructions indicates a maximal displacement of 1–2 mm. Therefore, nonoperative treatment was chosen despite involvement of the acetabular roof and slight incongruency (minimally centralized femoral head).

Matta suggested a maximum tolerable displacement of 3 mm.⁵^,¹³

Certain displaced fractures with fracture lines extending into potentially less relevant weight bearing areas, such as small posterior rim fractures with a congruent and stable hip joint, can be treated nonoperatively. These fractures should be located outside the weight-bearing area of the joint, which corresponds to the superior part of the joint according to Rowe and Lowell.¹⁴ Optimized quantification of this area was reported by the roof–arc angle measurements according to Matta⁴^,⁵ and in the CT evaluation according to Olson et al¹² (see later).

A special situation is the concept of secondary congruency in associated both-column fractures.¹ By definition, the complete joint surface is detached from the axial skeleton in associated both-column fractures and therefore the fragments can position around the femoral head in an almost anatomical manner (▶ Fig. 6.2). Matta suggested a maximum displacement of 10 mm gaps for nonoperative treatment of these fractures.⁴ As good results are less likely compared to open anatomical reduction and internal fixation, the indication for conservative treatment of these injuries should be mainly in elderly patients.

Fig. 6.2 Associated both column fracture with concentric positioning of the fragments around the femoral head with good secondary congruency. After 4 years, the fracture is healed in slight malalignment and the joint is congruent without signs of osteoarthritis.

The clinical outcome of secondary congruency was analyzed by Gänsslen et al in 35 relatively young patients (mean age 37 years) with displaced associate both-column fractures who were treated nonoperatively for different reasons.¹⁵ A total of 88% healed with good secondary congruency; 80% of these patients reported none or little pain at follow-up; and 77% reported a good or excellent clinical outcome using in the Merle d’Aubigné score. Radiological joint failure was seen in 17%. However, no parameters allowing prediction of the long-term result could be identified.

Local soft tissue injuries, especially the Morel-Levallé lesions, are considered to be potential contraindications for operative treatment due to the risk of secondary wound infection. This injury is often observed in the trochanteric region.¹ The resulting epifascial space is filled with fluids and necrotic fat tissue.¹⁶^,¹⁷ Even in closed injuries, there is an increased risk for infection.¹^,¹⁶^,¹⁸ Therefore, debridement and necrosectomy, either open or minimally invasive, should be carried out prior to open reduction and internal fixation.¹⁶^,¹⁹^,²⁰ If these lesions were inadequately treated or infection persisted, nonoperative fracture treatment should be considered.

Medical contraindications are relative and depend on their severity and the risk for the patient, which depends on the duration and invasiveness of the proposed procedure itself and the accompanying anesthetic risks. Thus, a risk–benefit analysis is mandatory.

For evaluation of the extent of involvement of the weight-bearing area of the hip joint, different criteria were reported. The most common criterion is the roof–arc measurement according to Matta.⁴^,⁵

Using the three standard views, the medial roof–arc angle is measured using the AP pelvic X-ray, the posterior roof–arc angle using the iliac oblique view, and the anterior roof–arc angle using the obturator oblique view. A vertical line through the center of rotation of the hip joint is drawn. A second line from the center of rotation to the most lateral acetabular fracture line is drawn and the angle between these two lines is measured and referred to as roof–arc angle. Limitations of this method are posterior wall fractures that are often outside the acetabular roof and associated both-column fractures where the center of rotation can often not be determined.

Matta recommended roof–arc dependent nonoperative treatment in the following situations⁴^,⁵:

Congruent hip joint (femoral head and acetabulum roof are parallel)
Roof–arc angle > 45 degrees in all three standard views (▶ Fig. 6.3)
No relevant posterior wall fracture (CT scan may be necessary)

Fig. 6.3 Example of roof–arc measurement in the three standard X-rays.

Several data are available on roof–arc measurement values to decide between operative and nonoperative treatment.

In simulated transtectal and juxtatectal transverse fractures, a mean anterior roof–arc angle of 52 degrees, a mean medial roof–arc angle of 46 degrees, and a mean posterior roof–arc angle of 62 degrees were measured.²¹ The authors concluded that lower roof–arc angles are considered indications for operative treatment.

In a clinical analysis, normal values of 42 degrees for the anterior, 39 degrees for the medial, and 55 degrees for the posterior roof–arc angles were reported.²² Thus, roof–arc angles below these values suggest relevant involvement of the acetabular roof, whereas values ≥45 degrees, 45 degrees, and 62 degrees state no relevant involvement of the weight-bearing area and therefore nonoperative treatment may be suggested.

Another method of analysis of the extent of involvement of the acetabular roof was reported by Olson et al by measuring the size of the intact acetabular roof using CT.¹² The most proximal 10 mm of the acetabulum axial images were analyzed, as these correspond to the conventional roof–arc angles of 45 degrees.

Olson et al suggest conservative treatment in addition to the criteria by Matta if the proximal 10 mm of the acetabular roof remained intact without significant fracture lines (▶ Fig. 6.4).