Fractures of the ilium are among the most common pelvic injuries in small animals and typically occur as part of multi-site pelvic trauma following motor vehicle accidents or significant blunt impact. Because the ilium forms the largest portion of the pelvis and functions as a primary load-bearing strut, instability or displacement in this region can compromise pelvic canal size, weight transmission from the hindlimb, and acetabular alignment. Surgical stabilization is recommended for most ilial body fractures to restore normal pelvic biomechanics, prevent chronic pain, and maintain normal limb function.

I. Pre-Operative Assessment and Planning

Ilium fractures rarely occur in isolation. A careful, systematic assessment is mandatory to identify concurrent life-threatening injuries.

1. Indications for Surgical Stabilization

Internal fixation of the ilium is strongly recommended when any of the following are present:

A. Narrowing of the pelvic canal

Most ilial body fractures are oblique, causing the caudal segment to displace medially. This can reduce canal diameter and predispose to:

• Chronic constipation

• Dyschezia

• Difficulty whelping (females)

• Long-term discomfort and gait abnormalities

B. Associated acetabular fracture

Stabilization of the ilium is essential before acetabular reduction because it restores the mechanical foundation for subsequent joint reconstruction.

C. Multisite pelvic instability

Fracture of the ilium combined with pubic, ischial, or sacroiliac injury destabilizes the hemipelvis. Ilium stabilization re-establishes weight-bearing alignment.

D. Markedly displaced ilial wing fractures

Although non-weight-bearing, severe displacement may require fixation for cosmetic alignment and to support the gluteal musculature.

2. Diagnostic Evaluation

A. Systemic Trauma Screening

High-impact trauma may produce:

• Pulmonary contusions

• Pneumothorax

• Myocardial bruising

• Hemorrhage

• Urethral or bladder rupture

These must be stabilized prior to orthopedic surgery.

B. Neurological Assessment

Evaluate for injury to:

• Lumbosacral trunk

• Sciatic nerve

• Obturator nerve

Neurological deficits may influence prognosis and postoperative mobility.

C. Imaging Requirements

• Orthogonal pelvic radiographs (VD + lateral) for initial assessment

• CT scanning is highly recommended for definitive preoperative planning, providing accurate delineation of fragment geometry, pelvic canal narrowing, and sacroiliac involvement

II. Surgical Repair of Ilial Body Fractures

Optimal timing: Within 3–4 days of injury to allow reduction before fibrous adhesion formation.

1. Surgical Approach

A standard lateral approach to the ilium is performed.

Key steps include:

• Incising along the cranial border of the wing

• Elevating the middle gluteal muscle dorsally

• Retraction of the deep gluteal muscle to access the lateral ilial surface

• Preserving neurovascular structures (cranial gluteal vessels, sciatic nerve)

Adequate exposure of the lateral ilium is essential for plate application.

2. Reduction Principles

The typical displacement involves medial rotation of the caudal ilial segment. Reduction requires:

• Traction applied to the greater trochanter

• Levering the caudal segment laterally using bone-holding or reduction forceps

• Rotational correction achieved through controlled manipulation of the caudal fragment

Once the pelvic canal width is restored, temporary fixation (K-wires or pointed reduction forceps) can be applied.

III. Fixation Techniques

Bone plating of the lateral ilium is the gold-standard stabilization method.

1. Plate Selection and Contouring

Common implant choices:

• Dynamic Compression Plate (DCP)

• Limited Contact DCP (LC-DCP)

• Locking Compression Plate (LCP)

The plate must be pre-contoured to match the natural curvature of the ilium. A slightly more concave contour is recommended to ensure outward tension when the plate is tightened, helping restore the pelvic canal diameter.

Order of fixation:

1. Attach plate to the caudal segment first

   • This gives the surgeon a stable lever arm for traction

2. Apply lateral traction via the greater trochanter

3. Seat the cranial end of the plate and secure it with screws to the cranial ilial body

This sequence facilitates anatomic reduction.

2. Screw Placement Guidelines

The ilium has variable bone density. For maximum stability:

• Place screws into the sacral body when possible to enhance purchase

• Use longer cortical screws to maximize thread engagement

• For oblique fractures, lag screws can be added to increase interfragmentary compression

• In small breeds, pins + compression wire can be used as an alternative

3. Addressing Concurrent Injuries

When ilial fractures coexist with additional pelvic injuries:

• Stabilize the ilium first (creates a foundation for acetabular or sacroiliac repair)

• Reassess alignment after ilium fixation before proceeding to adjacent structures

• Avoid over-manipulation of already compromised soft tissues

IV. Postoperative Management

1. Activity Restriction

Strict confinement is essential until radiographic healing occurs:

• Cage rest for 6–10 weeks

• Short, controlled leash walks for elimination

• No stairs, jumping, or running

• Provide padded bedding to prevent decubital sores

2. Implant Management

• Plates and screws are typically left in place permanently

• Removal is only indicated for implant irritation, infection, or loosening

• Routine removal is not recommended

3. Postoperative Monitoring

Monitor for:

• Neurological deterioration

• Constipation or discomfort from pelvic canal narrowing

• Implant failure (rare with proper fixation)

• Persistent pain or lameness

Radiographs at 6 weeks and 10 weeks confirm healing progression.

V. Prognosis

With correct fixation and restricted postoperative activity, most patients regain excellent pelvic stability and near-normal limb function. Early stabilization prevents long-term issues such as:

• Abnormal gait

• Chronic pelvic canal narrowing

• Persistent lameness

• Malunion deformities

Prognosis is strongly influenced by the presence of neurological injury, concurrent pelvic fractures, and the level of preoperative displacement.
FAQs: Ilium Fracture Repair

1. When is surgical fixation of the ilium mandatory?

Surgery is strongly indicated when there is:

• Medial displacement of the caudal ilial segment causing pelvic canal narrowing

• Concurrent acetabular fracture requiring a stable foundation for reduction

• Multi-site pelvic instability (ilium + pubis/ischium/SIJ)

• Marked displacement of the iliac wing
  Non-displaced or minimally displaced wing fractures may be managed conservatively.

2. What is the best imaging modality for preoperative planning?

CT is highly recommended—especially for complex or multi-fragment fractures—as it provides precise alignment, canal measurements, and SIJ status. Standard pelvic radiographs are acceptable but less detailed.

3. What is the preferred surgical approach?

A lateral approach to the ilial wing and body, retracting the middle and deep gluteal muscles dorsally, provides broad exposure for plate placement and reduction.

4. How do ilial body fractures typically displace?

Most are oblique with the caudal segment displaced medially, causing narrowing of the pelvic canal. Reduction requires lateral traction of the trochanter and controlled levering of the caudal fragment.

5. What is the recommended fixation method?

A contoured lateral bone plate (DCP, LC-DCP, or LCP) is the gold standard. The plate should be slightly more concave than the natural bone curvature to help restore canal diameter during fixation.

6. How should screws be placed for maximum stability?

Place screws into the sacral body when possible, as ilial bone is thin and offers weaker purchase. Long cortical screws increase stability. Lag screws are beneficial for oblique fractures.

7. When are tension-band constructs indicated?

In small breeds with oblique ilial fractures or when plating is not feasible, pins + tension-band wire may be used to achieve interfragmentary compression.

8. What is the recommended order of fixation?

Plate the caudal ilial segment first, then secure the cranial segment while applying traction at the trochanter. This helps restore pelvic alignment and canal width.

9. How should acetabular or sacroiliac injuries be handled when present?

Always stabilize the ilium first, then proceed with acetabular or SIJ repair. This restores a mechanical foundation for further reconstruction.

10. What are the most common complications?

• Malreduction causing persistent pelvic canal narrowing

• Implant loosening (rare with correct technique)

• Neurological deficits from pre-existing trauma

• Constipation/dyschezia during early healing

• Pain associated with muscle elevation or implant irritation

11. How long must activity be restricted?

Strict confinement for 6–10 weeks, with radiographs taken at 6 and 10 weeks to confirm healing.

12. Do ilial plates require removal?

Generally no. Plates can remain indefinitely unless the patient develops irritation, infection, or implant failure.