Malgaigne Fracture: Vertical Shear : Wheeless' Textbook of Orthopaedics

- Discussion:
- frx consist of frxs of both pubic rami plus posterior frx of SI complex or sacrum:
- there is vertically oriented frx thru anterior and posterior pelvis together w/ superior displacement of lateral "acetabulum-containing" fragment of pelvis;
- this injury is characterized by rupture of entire pelvic floor, including posterior SI complex as well as sacrospinous and sacrotuberous ligaments;
    - vertial stability:
             - sacrotuberous ligament: stout ligament which exteds to the posterolateral sacrum and dorsal aspect of the posterioriliac spine to the ischial tuberosity;
             - posterior sacroiliac ligaments, provides vertical stabilityto the pelvis.
    - injury may be unilateral or bilateral;
- these frx are unstable owing to the significant posterior pelvic disruption;
- usually results from fall from height onto lower limbs;

- Physical Exam:
- displacement in vertical plane is diagnosed by applying one hand to pelvic iliac crest and using other to apply traction to leg which should cause displacement in vertical plane;

- Radiographic Evaluation:
- anterior lesion: (see: anterior pelvic injuries)
- disruption of the symphysis
- disruption of the inferior and superior pubic rami
- disruption of all four rami
- disruption of two rami plus symphysis pubis;
- posterior lesion: (posterior pelvic injury:)
- posterior lesion may be a fracture of ileum
- dislocation or frx dislocation of SI joint
- more than 5-15 mm of cephalic displacement of posterior SI complex on outlet views gap implies instability;
- frx of 4th or 5th lumbar transverse process;
- ref: Fracture of the transverse process of the fifth lumbar vertebra.
- detachment of bony insertion of sacrospinous ligaments from either sacrum or ischial spine are evidence of vertical instability;

- frx of sacrum;
- the following is an example of a Malgaine frx equilavent, in a patient who fell out of a tree;
- the frx appears to have a shear component w/ vertical displacement of the fracture;
- ref:
- The role of standard roentgenograms in the evaluation of instability of pelvic ring disruption.
- Fracture of the transverse process of the fifth lumbar vertebra.
- Is a fracture of the transverse process of L5 a predictor of pelvic fracture instability?

- Initial Management:
- Malgaigne frxs are associated w/ heavy bleeding (see: bleeding from pelvic frx), requiring on average 7-8 units of pRBC;
- if pelvis is unstable w/ vertical migration or posterior displacement, then place of supracondylar femoral pin w/ 25-30 lbs of traction is used to pull the pelvis back down into a reduced position (w/ equal leg lengths);
- approximately one half of patients treated non operatively w/ traction may expect long term low back pain and/or leg discomfort;
- approximately one third will have a pelvic obliquity and/or limp;
- ref: Traction vertical shear pelvic ring fracture: a marker for severe arterial injury? A case report.

- External Fixation:
- serves only as adjunct to other forms of treatment for these frx;
- has little potential to control pelvic frx w/ involvement of SI joint, including sacral frxs & some posterior iliac wing fractures;
- indications:
- isolated pelvic frxs when pt does not require mobilization
- use traction to reduce vertical and/or posterior displacement, while external fixation frame is used to control rotation;
- complex frxs: where internal fixation may not be suitable;
- in the study by Lindahl J, et al (1999), the external fixator failed to give and maintain a proper reduction in 38 of the 40 type-C injuries.
- in type-C injuries more than 10 mm of residual vertical displacement of the injury to the posterior pelvic ring was significantly related to poor outcome;
- in 14 patients in this unsatisfactory group poor functional results were also affected by associated nerve injuries;
- special considerations:
- resistance to verticle displacement is almost doubled by using 5mm rather than 4 mm half pins for iliac wing fixation;
- stability is also enhanced by adding second pin group in each ilium between antero-inferior & superior iliac spines;
- most rigid construction:
                - involves combination of SI jont fixation & external frame placed anteriorly;
- ref:
          - Failure of reduction with an external fixator in the management of injuries of the pelvic ring. Long-term evaluation of 110 patients.
          - Anatomic and radiographic considerations in the placement of anterior pelvic external fixator pins.
- Biomechanical testing of new and old fixation devices for vertical shear fractures of the pelvis.
- External fixation of unstable Malgaigne fractures: the comparative mechanical performance of a new configuration.
- Unstable fractures of the pelvis treated by external fixation.
- The Role of External Fixation in Pelvic Disruptions.

- Posterior Fixation:
    - SI jont fixation
           - Vertically unstable pelvic fractures fixed with percutaneous iliosacral screws: does posterior injury pattern predict fixation failure?
    - sacral bars:
       - safest method of stabilizing a sacral fracture is to use sacral bars;
       - these bars pass from one posterior superior spine to other, thereby making direct fixation of fracture w/ lag screws unnecessary;
           - two sacral bars are used to prevent rotation;
       - bars must be posterior to sacrum to avoid entering sacral spinal canal