Orthopaedics: when is conservative management of pelvic fractures appropriate?
Malcolm Jack - Head of Surgery
EBVS®European Specialist in Small Animal Surgery
BVSc(Hons) MANZCVS DipECVS MRCVS
The following information is by no means a comprehensive guide, but rather to give an overview of some of the considerations for deciding if conservative management of a pelvic fracture may be successful, or is an appropriate management choice. We should begin with the fact that the majority of pelvic fractures require or would benefit from surgery to achieve an optimal outcome.
Firstly, we need to understand the structure and function of the pelvis to better decide if conservative management may be appropriate. The pelvis transfers weight-bearing forces through the femur to the axial skeleton (Figure 1).
We should view the pelvis as a rigid box-like structure, and therefore we have the general rule that for fracture and displacement to occur, the pelvis must be fractured in more than one place. For example (Figure 2), the fracture through the ilium (black lightning bolt) could not displace without fracture of the pubis and ischium (blue lightning bolt).
Fractures along this primary weight-bearing pathway include fractures of the acetabulum, ilium, sacrum, and sacroiliac luxations. (Figure 3). Weight bearing elements were involved in 89% of cases in one study.
As a general rule if there is fracture or luxation along this pathway, think surgery.
Possible indications for conservative management:
- Minimally displaced (< 50%) SI luxation. Without contraindications, for example uncontrollable pain. This is an exception to the above rule, asSI luxations are along the primary weight bearing pathway.
- Minimal reduction in pelvic canal diameter (and not more than 50% reduction). Large reductions in pelvic canal diameter can cause constipation or obstipation, especially a concern in cats. Narrowing of the pelvic canal in an entire female also has the potential to prevent natural parturition.
- Isolated pubic/ischial fractures (Figure 4 and 5). Typically, these can be managed without surgery. The ischium is however an important origin for semitendinosus and semimembranosus, so if the injury occurred in a working dog or agility dog, surgery may be recommended to try and obtain maximum performance after fracture healing.
- With appropriate analgesia the patient is comfortable +/- ambulatory
- Financial limitations meaning surgery isn’t an option (as long as animal welfare is not jeopardised)
- Excessive pain (possible nerve entrapment) or instability. Ischial fractures can cause direct irritation/entrapment of the sciatic nerve where it passes over the bone, just caudal to the acetabulum, before coursing down the leg. If the level of pain clinically does not match that which would be expected, then nerve pain should be considered and addressed, possibly with surgery.
- ischium/Pubis – If there is concern regarding rupture or fracture avulsion of the prepubic tendon leading to an abdominal wall defect, then surgery may be required.
- Don’t forget injuries to other body systems! This is very important no matter if the management of pelvic fractures is surgical or conservative. The cat in Figures 4 and 5 was referred and then diagnosed with a ruptured urethra. One study on vehicular injury demonstrated that 71% of patients had multiple body system injuries.
- Does the radiograph fit the clinical picture? A unilateral pelvic injury should not stop a dog from moving its other hind limb or trying to walk on the contralateral limb. Consider if there could be another issue at play, such as a spinal injury. Utilise your neurological exam.
We have concentrated here on the type, location and displacement of the bony injury. However, it is very important to remember the other local and distant sites that can be injured in a traumatic incident.
This is not an exhaustive list and there are exceptions to some of the previously mentioned scenarios.
You are always welcome to send in you radiographs for assessment by one of our surgeons if you would like to be sure that conservative management is the right option.