Acetabulum Fractures Workup
- Author: Mihir M Thacker, MBBS, MS(Orth), DNB(Orth), FCPS(Orth), D'Ortho; Chief Editor: William L Jaffe, MD more...
The complicated anatomy of the acetabulum necessitates clear-cut visualization of the fracture fragments and their relationships with each other and the rest of the pelvis if anatomic reconstruction of the acetabulum is planned. The following imaging modalities can be used:
Plain radiographs - Pelvis with both hips (AP view), Judet views, and, if required, inlet and outlet views of the pelvis (in cases with concomitant pelvic injury)
Computed tomography (CT) - Plain and with three-dimensional (3D) reconstructions
Doppler ultrasonography or venography may be performed in cases where deep vein thrombosis (DVT) is suspected.
Pelvis with both hips
This is an essential radiograph and may depict the following:
Associated pelvic ring fractures independent of the acetabular fracture passing through the iliac wing, obturator foramen, or the sacrum
Dislocation through or disruption of one or more joints in the pelvic ring
Rarely, a bilateral acetabular fracture
The acetabular fracture itself
This view enables visualization of the six fundamental radiologic landmarks of the acetabulum, as follows:
Borders of the anterior wall (acetabulo-obturator line) and posterior wall of the acetabulum
Roof or dome of the acetabulum
Teardrop of Köhler
Ilioischial line of Duverney-Parent
In the obturator oblique technique, the injured hip is raised to 45°, and the beam is centered over a point 1 fingerbreadth below and medial to the anterior superior iliac spine. In a correctly taken obturator oblique, the anterior and posterior iliac spines are superimposed, the iliac wing is seen in section as narrow as possible, and, correspondingly, the obturator foramen is seen as large as possible. Features to be studied include the following:
Articular surface, especially the posterior lip
Obturator foramen and the anterior column
Iliac wing in section
Junction of the anterior and posterior columns as seen as a line just above the roof
In the iliac oblique technique, the uninjured hip is elevated to 45°, with the injured part resting on the table. The beam is centered one fingerbreadth below the level of the anterior superior iliac spine and at the midpoint of a transverse line from the anterior superior iliac spine to the midline. In a correctly positioned iliac oblique, the iliac wing is seen widely spread out and the obturator ring is as thin as possible. Features to be studied include the following:
Anterior lip of the acetabulum
Posterior column and posterior border of the iliac bone
Interpretation of the plain films is based on understanding the normal radiographic lines of the acetabulum and what each line represents. Disruption of any of the normal lines of the acetabulum represents a fracture involving that portion of the bone. Displacement of the articular surface is inferred by displacement of these normal lines of the acetabulum.
On the AP view, the inferior three fourths of the iliopectineal line represents the pelvic brim and is a landmark of the anterior column. The superior fourth of this line is formed by the tangency of the x-ray beam to the superior quadrilateral surface and the greater sciatic notch. The ilioischial line is formed by the tangency of the x-ray beam to the posterior portion of the quadrilateral surface and is, therefore, a radiographic landmark of the posterior column.
The teardrop and ilioischial line both result from the tangency of the x-ray beam to a portion of the quadrilateral surface. Thus, they are always superimposed in the normal acetabulum. Separation of the teardrop and the ilioischial line indicates rotation of the hemipelvis or fracture of the quadrilateral surface.
The roof of the acetabulum is a radiographic landmark resulting from the tangency of the x-ray beam to the subchondral bone of the superior acetabulum. Interruption of the radiographic line of the roof is indicative of a fracture involving the superior acetabulum.
The anterior rim is the lateral margin of the anterior wall of the acetabulum and is contiguous with the inferior margin of the superior pubic ramus. The posterior rim is the lateral margin of the posterior wall of the acetabulum. Inferiorly, the posterior rim is contiguous with the posterior horn of the acetabulum.
In most cases, the fracture can be classified properly from plain films alone. Plain films are usually best for assessing the congruence between the femoral head and the roof of the acetabulum.
Roof-arc angles are used to assess the size of the intact portion of acetabulum.[17, 18, 19, 20] These angles are made on the AP, obturator, and iliac oblique radiographic views.
A vertical line is drawn to the geometric center of the acetabulum. Another is drawn through the point where the fracture line intersects the radiographic roof of the acetabulum and again to the geometric center of the acetabulum. The angle drawn in this way represents the medial, anterior, or posterior roof arc as seen on the AP, obturator oblique, or iliac oblique view, respectively. The roof-arc measurements roughly describe the position and orientation of the acetabular fracture and, therefore, the intact portion of superior acetabular articular surface.
A similar determination can be made from the CT scan. The CT scan of the superior acetabular articular surface from the vertex to 10 mm inferior to the vertex is equivalent to an area described by all three roof-arc measurements of 45°. At 10 mm below the acetabular vertex, the subchondral bone appears as a ring or arc.
If nonoperative treatment is to be considered, the head should remain congruous with the roof of the acetabulum on the three views of the pelvis with the patient out of traction, and all roof-arc measurements should be more than 45°, or there should be no displaced fracture lines involving the superior acetabular articular surface in the superior 10 mm of the acetabulum on CT.
Vrahas et al, in a cadaveric study, concluded that fractures that have a medial roof-arc angle of 45° or less, an anterior roof-arc angle of 25° or less, or a posterior roof-arc angle of 70° or less across the weightbearing portion of the acetabulum should be treated operatively.
Roof-arc measurements are not commonly used. This technique is most applicable to the anterior column and less applicable to the posterior column. Roof-arc measurements are particularly helpful in evaluating the anterior column component of a T-shaped fracture. If the anterior column component is low (< 10 mm of the acetabular vertex), only the posterior portion of the fracture must be addressed surgically.
The use of CT for acetabular fractures has revolutionized the imaging of a particularly difficult area and, with 3D reconstruction, has enormously facilitated the visualization of the fracture anatomy, the degree of comminution, and associated fracture patterns; it has also helped in the preoperative planning of the surgical reconstruction.[21, 22, 23, 24, 25]
It is important to have sections taken at 2- or 3-mm intervals; incarcerated fragments may be missed if sections are taken at 5-mm intervals.
Three-dimensional CT is an invaluable tool for demonstrating the overall fracture orientation in displaced fractures, as well as for deciding the choice of operative approach to the fracture. Because of smoothening artifacts, however, it may not depict minimally displaced fractures.
Special views are available that enable selective study of the details of the acetabular fracture after computer subtraction of the femoral head from the image. These provide unrestricted access for visualization of the fracture.
Axial images are more sensitive than plain radiographs for demonstrating the following:
Location and extent of the acetabular fracture
Degree of comminution, rotation of the fragments, and impaction of the weightbearing dome and the posterior wall
Intra-articular/incarcerated fragments (see the image below)
Injury to the femoral head
Minimally displaced iliac wing fractures and quadrilateral plate fractures that may have been missed on plain films
Sacroiliac joint integrity
Postoperatively, CT is an invaluable investigative tool whenever joint penetration by a fixation device is suspected (see the image below).
Laboratory studies that may be helpful include the following:
Hemoglobin and hematocrit levels
Type and crossmatch blood
Routine evaluation of fitness for anesthesia and major surgery
Hadley NA, Brown TD, Weinstein SL. The effects of contact pressure elevations and aseptic necrosis on the long-term outcome of congenital hip dislocation. J Orthop Res. 1990 Jul. 8(4):504-13. [Medline].
Judet R, Judet J, Letournel E. Fractures of the acetabulum: Classification and surgical approaches for open reduction. J Bone Joint Surg. 1964. 46A:1615-38.
Letournel E. Fractures of the Acetabulum. 2nd ed. New York. Springer-Verlag. 1993.
Letournel E. Acetabulum fractures: classification and management. Clin Orthop. 1980 Sep. (151):81-106. [Medline].
Milenkovic S, Saveski J, Radenkovic M, Vidic G, Trajkovska N. Surgical treatment of displaced acetabular fractures. Srp Arh Celok Lek. 2011 Jul-Aug. 139(7-8):496-500. [Medline].
Matta JM. Fractures of the acetabulum: accuracy of reduction and clinical results in patients managed operatively within three weeks after the injury. J Bone Joint Surg Am. 1996 Nov. 78(11):1632-45. [Medline].
Dakin GJ, Eberhardt AW, Alonso JE, et al. Acetabular fracture patterns: associations with motor vehicle crash information. J Trauma. 1999 Dec. 47(6):1063-71. [Medline].
Peltier LF. Complications associated with fractures of the Pelvis. J Bone Joint Surg. 1962. 44B:550-561.
Reed MH. Pelvic fractures in children. J Can Assoc Radiol. 1976 Dec. 27(4):255-61. [Medline].
Mears DC, Velyvis JH. Acute total hip arthroplasty for selected displaced acetabular fractures: two to twelve-year results. J Bone Joint Surg Am. 2002 Jan. 84-A(1):1-9. [Medline].
Mears DC, Velyvis JH, Chang CP. Displaced acetabular fractures managed operatively: indicators of outcome. Clin Orthop. 2003 Feb. 173-86. [Medline].
Porter SE, Schroeder AC, Dzugan SS, Graves ML, Zhang L, Russell GV. Acetabular fracture patterns and their associated injuries. J Orthop Trauma. 2008 Mar. 22(3):165-70. [Medline].
Matta JM, Mehne DK, Roffi R. Fractures of the acetabulum. Early results of a prospective study. Clin Orthop. 1986 Apr. (205):241-50. [Medline].
Olson SA, Bay BK, Chapman MW, Sharkey NA. Biomechanical consequences of fracture and repair of the posterior wall of the acetabulum. J Bone Joint Surg Am. 1995 Aug. 77(8):1184-92. [Medline].
Vrahas MS, Widding KK, Thomas KA. The effects of simulated transverse, anterior column, and posterior column fractures of the acetabulum on the stability of the hip joint. J Bone Joint Surg Am. 1999 Jul. 81(7):966-74. [Medline].
Thacker M. Post-operative management of acetabular fractures. Indian J Orthopaedics. 2002. 36(1):29-30.
Olson SA, Matta JM. The computerized tomography subchondral arc: a new method of assessing acetabular articular continuity after fracture (a preliminary report). J Orthop Trauma. 1993. 7(5):402-13. [Medline].
Matta J. Operative indications and choice of surgical approach for fractures of the acetabulum. Tech Orthop. 1986. 1:13-22.
Matta JM, Anderson LM, Epstein HC, Hendricks P. Fractures of the acetabulum. A retrospective analysis. Clin Orthop. 1986 Apr. (205):230-40. [Medline].
Øvre S, Madsen JE, Røise O. Acetabular fracture displacement, roof arc angles and 2 years outcome. Injury. 2008 Aug. 39(8):922-31. [Medline].
Brumback RJ, Holt ES, McBride MS, et al. Acetabular depression fracture accompanying posterior fracture dislocation of the hip. J Orthop Trauma. 1990. 4(1):42-8. [Medline].
Harley JD, Mack LA, Winquist RA. CT of acetabular fractures: comparison with conventional radiography. AJR Am J Roentgenol. 1982 Mar. 138(3):413-7. [Medline].
Tile M. Fractures of the Pelvis and Acetabulum. Baltimore. Lippincott Williams & Wilkins. 1984.
Borrelli J Jr, Peelle M, McFarland E, Evanoff B, Ricci WM. Computer-reconstructed radiographs are as good as plain radiographs for assessment of acetabular fractures. Am J Orthop. 2008 Sep. 37(9):455-9; discussion 460. [Medline].
Moed BR, Ajibade DA, Israel H. Computed tomography as a predictor of hip stability status in posterior wall fractures of the acetabulum. J Orthop Trauma. 2009 Jan. 23(1):7-15. [Medline].
Johnson EE, Kay RM, Dorey FJ. Heterotopic ossification prophylaxis following operative treatment of acetabular fracture. Clin Orthop. 1994 Aug. (305):88-95. [Medline].
Dailey SK, Archdeacon MT. Open reduction and internal fixation of acetabulum fractures: does timing of surgery affect blood loss and OR time?. J Orthop Trauma. 2014 Sep. 28(9):497-501. [Medline].
Mears DC, Rubash HE. Extensile exposure of the pelvis. Contemp Orthop. 1983. 6:21.
Mears DC, Rubash HE, eds. Pelvic and Acetabular Fractures. New Jersey. Slack Inc. 1986.
Dean DB, Moed BR. Late salvage of failed open reduction and internal fixation of posterior wall fractures of the acetabulum. J Orthop Trauma. 2009 Mar. 23(3):180-5. [Medline].
Isaacson MJ, Taylor BC, French BG, Poka A. Treatment of acetabulum fractures through the modified Stoppa approach: strategies and outcomes. Clin Orthop Relat Res. 2014 Nov. 472(11):3345-52. [Medline]. [Full Text].
Ebraheim NA, Patil V, Liu J, Haman SP. Sliding trochanteric osteotomy in acetabular fractures: a review of 30 cases. Injury. 2007 Oct. 38(10):1177-82. [Medline].
Collinge C, Archdeacon M, Sagi HC. Quality of radiographic reduction and perioperative complications for transverse acetabular fractures treated by the Kocher-Langenbeck approach: prone versus lateral position. J Orthop Trauma. 2011 Sep. 25(9):538-42. [Medline].
Helfet DL, Schmeling GJ. Management of complex acetabular fractures through single nonextensile exposures. Clin Orthop. 1994 Aug. (305):58-68. [Medline].
Routt ML Jr, Swiontkowski MF. Operative treatment of complex acetabular fractures. Combined anterior and posterior exposures during the same procedure. J Bone Joint Surg Am. 1990 Jul. 72(6):897-904. [Medline].
Schmidt CC, Gruen GS. Non-extensile surgical approaches for two-column acetabular fractures. J Bone Joint Surg Br. 1993 Jul. 75(4):556-61. [Medline].
Harris AM, Althausen P, Kellam JF, Bosse MJ. Simultaneous anterior and posterior approaches for complex acetabular fractures. J Orthop Trauma. 2008 Aug. 22(7):494-7. [Medline].
Bosse MJ, Poka A, Reinert CM, et al. Preoperative angiographic assessment of the superior gluteal artery in acetabular fractures requiring extensile surgical exposures. J Orthop Trauma. 1988. 2(4):303-7. [Medline].
Juliano PJ, Bosse MJ, Edwards KJ. The superior gluteal artery in complex acetabular procedures. A cadaveric angiographic study. J Bone Joint Surg Am. 1994 Feb. 76(2):244-8. [Medline].
Reinert CM, Bosse MJ, Poka A, et al. A modified extensile exposure for the treatment of complex or malunited acetabular fractures. J Bone Joint Surg Am. 1988 Mar. 70(3):329-37. [Medline].
Clement B. Master Techniques in Orthopedic Surgery: The Hip. Lippincott Williams & Wilkins. 1998.
Ganorkar S, Thacker M, Thakkar CJ. Implant selection and placement in acetabular fractures. Indian J Orthopaedics. 2002. 36(1):29-30.
Mehin R, Jones B, Zhu Q, Broekhuyse H. A biomechanical study of conventional acetabular internal fracture fixation versus locking plate fixation. Can J Surg. 2009 Jun. 52(3):221-8. [Medline]. [Full Text].
Gay SB, Sistrom C, Wang GJ, et al. Percutaneous screw fixation of acetabular fractures with CT guidance: preliminary results of a new technique. AJR Am J Roentgenol. 1992 Apr. 158(4):819-22. [Medline].
Parker PJ, Copeland C. Percutaneous fluoroscopic screw fixation of acetabular fractures. Injury. 1997 Nov-Dec. 28(9-10):597-600. [Medline].
Starr AJ, Jones AL, Reinert CM, Borer DS. Preliminary results and complications following limited open reduction and percutaneous screw fixation of displaced fractures of the acetabulum. Injury. 2001 May. 32 Suppl 1:SA45-50. [Medline].
Starr AJ, Reinert CM, Jones AL. Percutaneous fixation of the columns of the acetabulum: a new technique. J Orthop Trauma. 1998 Jan. 12(1):51-8. [Medline].
Kazemi N, Archdeacon MT. Immediate full weightbearing after percutaneous fixation of anterior column acetabulum fractures. J Orthop Trauma. 2012 Feb. 26(2):73-9. [Medline].
Heeg M, Visser JD, Oostvogel HJ. Injuries of the acetabular triradiate cartilage and sacroiliac joint. J Bone Joint Surg Br. 1988 Jan. 70(1):34-7. [Medline].
Bucholz RW, Ezaki M, Ogden JA. Injury to the acetabular triradiate physeal cartilage. J Bone Joint Surg Am. 1982 Apr. 64(4):600-9. [Medline].
Dora C, Zurbach J, Hersche O, Ganz R. Pathomorphologic characteristics of posttraumatic acetabular dysplasia. J Orthop Trauma. 2000 Sep-Oct. 14(7):483-9. [Medline].
Weber M, Berry DJ, Harmsen WS. Total hip arthroplasty after operative treatment of an acetabular fracture. J Bone Joint Surg Am. 1998 Sep. 80(9):1295-305. [Medline].
Bellabarba C, Berger RA, Bentley CD, et al. Cementless acetabular reconstruction after acetabular fracture. J Bone Joint Surg Am. 2001 Jun. 83-A(6):868-76. [Medline].
Boraiah S, Ragsdale M, Achor T, Zelicof S, Asprinio DE. Open reduction internal fixation and primary total hip arthroplasty of selected acetabular fractures. J Orthop Trauma. 2009 Apr. 23(4):243-8. [Medline].
Bartlett CS, DiFelice GS, Buly RL. Cardiac arrest as a result of intraabdominal extravasation of fluid during arthroscopic removal of a loose body from the hip joint of a patient with an acetabular fracture. J Orthop Trauma. 1998 May. 12(4):294-9. [Medline].
Haidukewych GJ, Scaduto J, Herscovici D Jr, et al. Iatrogenic nerve injury in acetabular fracture surgery: a comparison of monitored and unmonitored procedures. J Orthop Trauma. 2002 May. 16(5):297-301. [Medline].
Helfet DL, Anand N, Malkani AL, et al. Intraoperative monitoring of motor pathways during operative fixation of acute acetabular fractures. J Orthop Trauma. 1997 Jan. 11(1):2-6. [Medline].
Middlebrooks ES, Sims SH, Kellam JF, Bosse MJ. Incidence of sciatic nerve injury in operatively treated acetabular fractures without somatosensory evoked potential monitoring. J Orthop Trauma. 1997 Jul. 11(5):327-9. [Medline].
Johnson EE, Eckardt JJ, Letournel E. Extrinsic femoral artery occlusion following internal fixation of an acetabular fracture. A case report. Clin Orthop. 1987 Apr. (217):209-13. [Medline].
Probe R, Reeve R, Lindsey RW. Femoral artery thrombosis after open reduction of an acetabular fracture. Clin Orthop. 1992 Oct. (283):258-60. [Medline].
Burd TA, Lowry KJ, Anglen JO. Indomethacin compared with localized irradiation for the prevention of heterotopic ossification following surgical treatment of acetabular fractures. J Bone Joint Surg Am. 2001 Dec. 83-A(12):1783-8. [Medline].
Kendoff D, Gardner MJ, Citak M, Kfuri M Jr, Thumes B, Krettek C. Value of 3D fluoroscopic imaging of acetabular fractures comparison to 2D fluoroscopy and CT imaging. Arch Orthop Trauma Surg. 2007 Aug 7. [Medline].
Moed BR, Karges DE. Prophylactic indomethacin for the prevention of heterotopic ossification after acetabular fracture surgery in high-risk patients. J Orthop Trauma. 1994. 8(1):34-9. [Medline].
Johnson EE, Matta JM, Mast JW, Letournel E. Delayed reconstruction of acetabular fractures 21-120 days following injury. Clin Orthop. 1994 Aug. (305):20-30. [Medline].
Shim VB, Böshme J, Vaitl P, Josten C, Anderson IA. An efficient and accurate prediction of the stability of percutaneous fixation of acetabular fractures with finite element simulation. J Biomech Eng. 2011 Sep. 133(9):094501. [Medline].
Wright R, Barrett K, Christie MJ, Johnson KD. Acetabular fractures: long-term follow-up of open reduction and internal fixation. J Orthop Trauma. 1994 Oct. 8(5):397-403. [Medline].
Mayo KA. Open reduction and internal fixation of fractures of the acetabulum. Results in 163 fractures. Clin Orthop. 1994 Aug. (305):31-7. [Medline].
Pennal GF, Davidson J, Garside H, Plewes J. Results of treatment of acetabular fractures. Clin Orthop. 1980 Sep. (151):115-23. [Medline].
Ragnarsson B, Mjoberg B. Arthrosis after surgically treated acetabular fractures. A retrospective study of 60 cases. Acta Orthop Scand. 1992 Oct. 63(5):511-4. [Medline].
Brown GA, Firoozbakhsh K, Gehlert RJ. Three-dimensional CT modeling versus traditional radiology techniques in treatment of acetabular fractures. Iowa Orthop J. 2001. 21:20-4. [Medline].
Citak M, Gardner MJ, Kendoff D, Tarte S, Krettek C, Nolte LP, et al. Virtual 3D planning of acetabular fracture reduction. J Orthop Res. 2008 Apr. 26(4):547-52. [Medline].
|Fracture type||Letournel,  %
(n = 567)
|Matta,  %
(n = 255)
|Dakin et al,  %
(n = 85)
|Transverse with posterior wall||20.6||23.5||35.3|
|Anterior column with posterior hemitransverse||8.8||5.9||3.5|
|Posterior column with posterior wall||3.5||3.9||18.8|