Stability of posterior fracture-dislocations of the hip. Quantitative assessment using computed tomography.

Classifications in Brief: Letournel Classification for Acetabular Fractures

“…Radiographic and CT studies have evaluated posterior wall fractures and found instability may not be present unless more than 40% of the wall is fractured [3,8]. These authors suggest nonoperative management to be reasonable if less than 20% to 45% of the joint surface is involved [9,13,20]. The integrity of the posterior capsule may be responsible for this retained stability [22].…”

Acetabular fractures: easier classification with a systematic approach.

“…Size of the wall fragment is important for predicting posterior stability of the hip 120] and correlates with altered force distribution in the hip [32]. Based on studies of cadavers, if more than 40% of the poste rior wall is fractured, the risk of posterior in stability is increased significantly [20]. CT also aids in the assessment of comminution and associated impaction, both of which re late to prognosis [33].…”

Can Computed Tomography Predict Hip Stability in Posterior Wall Acetabular Fractures?

“…These fractures may be treated nonoperatively if there is a congruous and stable hip [16,20]. After initial successful closed reduction confirmed by plain radiographs in the emergent setting, 2-D CT is obtained for a more detailed evaluation of morphologic features of the fracture [3,5,6,8,11,16]. Studies using 2-D CT-derived-criteria indicate, in general, posterior wall fractures involving less than 20% of the posterior wall are stable and able to withstand physiologic loads, whereas those involving greater than 40% to 50% are unstable, leaving a wide range of posterior wall fractures classified as indeterminate [3,5,13].…”

“…After initial successful closed reduction confirmed by plain radiographs in the emergent setting, 2-D CT is obtained for a more detailed evaluation of morphologic features of the fracture [3,5,6,8,11,16]. Studies using 2-D CT-derived-criteria indicate, in general, posterior wall fractures involving less than 20% of the posterior wall are stable and able to withstand physiologic loads, whereas those involving greater than 40% to 50% are unstable, leaving a wide range of posterior wall fractures classified as indeterminate [3,5,13]. Therefore, the radiographic findings of subluxation of the hip or involvement greater than 50% of the posterior wall seen on CT are signs of hip instability and indications for operative repair [2,3,5,13,21].…”

“…or loss of joint parallelism, is indicative of dynamic hip instability [2,5,[13][14][15][17][18][19][20][21], and EUA is considered the gold standard for diagnosis of dynamic hip stability status [4,13,18,19]. However, EUA has not attained general clinical use status, and CT assessment of fragment size and position is thought to be able to identify clinically unstable hips requiring operative fixation [3,5,13].…”