Chapter 107 Fractures of the Pelvis
Pelvic fractures in dogs and cats are extremely common. Severe trauma, such as motor vehicular accidents, is usually the cause of pelvic fractures. Concurrent injuries to other body systems, including life-threatening injuries, are also common and must be identified and treated in a timely fashion. Several specific types of injury occur in the pelvis, including sacroiliac luxation, fractures of the non-articular portions of the pelvis, and articular fractures. Specific management protocols for each are described below.
ANATOMY
• Each half of the pelvis is composed of the ilium, ischium, pubis, and acetabulum, which are fused as the os coxae, or hip bone (Fig. 107-1).
• The sacroiliac joint has a limited range of motion and is composed of a synchondrosis craniodorsally and a synovial articulation ventrally.
• The sacrotuberous ligament extends from the caudolateral part of the apex of the sacrum and the transverse processes of the first caudal vertebra to the lateral part of the ischiatic tuberosity. The sacrotuberous ligament is absent in the cat.
• The sacrum and pelvic bones form a complete bony canal. Therefore, pelvic fractures usually are multiple, or pelvic fracture may be accompanied by sacral fracture or sacroiliac luxation. If a pelvic fracture appears to be single, examine radiographs carefully for evidence of additional undisplaced fractures. There are two exceptions to this general rule: fractures in very young dogs and impaction fractures of the acetabulum in adult dogs and cats. In the former case, the bones of young dogs can allow a fracture in one location and an incomplete fracture or plastic deformation (bending) without actual fracture of the bones of the pelvis in other areas. In the second instance, the femoral head is driven through the acetabulum by a lateral blow to the greater trochanter.
• The major weight-bearing regions of the pelvis are the sacroiliac joint, body of the ilium, and acetabulum.
DIAGNOSIS
Concurrent Thoracic and Abdominal Injuries
• Treat aggressively for shock and pain (see Chapters 6 and 156). After emergency treatment, complete the general physical examination as soon as possible.
• Concurrent thoracic, abdominal, intrapelvic, and spinal cord or peripheral nerve injuries are common with pelvic fractures. Management of cardiopulmonary, neural, and urinary system injuries and management of uncontrollable hemorrhage have priority over orthopedic injury.
• Radiograph the thorax routinely in animals with suspected pelvic fractures to identify pulmonary contusions, pneumo- or hemothorax, diaphragmatic herniation, and preexisting cardiac disease.
• Perform a 10-lead electrocardiogram and lead 2 rhythm strip every 12 hours for the first 48 to 72 hours following the trauma to identify cardiac dysrhythmias.
• Obtain abdominal radiographs, ultrasound examination, or diagnostic peritoneal lavage if free blood, urine, or bile is suspected in the abdomen.
• Perform excretory urography, cystography, or urethrography to identify the specific location of injury if rupture of the urinary tract is suspected.
• Urethral injuries are more common in male dogs where the urethra crosses through the ventral pelvic canal. The ability to urinate, presence of bruising or pubic fractures, and hematuria are not accurate predicators for or against urethral or bladder injury.
Pelvic Injuries
• Carefully palpate the pelvic bones, manipulate the hip joints, and perform a rectal examination to detect pelvic fractures and to check for a palpable defect in the rectal wall.
• Palpate the craniodorsal iliac crest, greater trochanter, and ischiatic tuberosity for symmetry, motion, and pain (Fig. 107-2).
• Radiograph the pelvis in at least two projections to fully evaluate bone injury. Sedate or anesthetize the patient to obtain high-quality diagnostic radiographs. Closely examine the coccygeal vertebrae and sacral foramina for fractures that may result in neurologic injury to the tail, perineum, and bladder.
• Although rectal tears are not commonly associated with pelvic fracture, failure to make an early diagnosis usually results in severe pelvic infection, sepsis, and patient death.
• If an animal is not in shock but is unwilling to stand, do not attempt to make the animal stand unless you have palpated the dorsal spinous processes for malalignment and pain (point tenderness). Check the animal’s spinal reflexes, including the sciatic and femoral nerve tracts; perception of noxious sensation over the pelvic limbs; withdrawal response; anal tone; and perineal sensation.
Figure 107-2 Diagram illustrating the normal position of the greater trochanter, iliac crest, and ischiatic tuberosity.
(From Fossum TW: Small Animal Surgery, 2nd ed. St Louis: Mosby, 2002.)
TREATMENT
Non-surgical Treatment
Nursing Care
• Dogs and cats with pelvic fractures often are reluctant to stand and may be unable to turn over. Turn these animals regularly, use a padded bed, and keep these animals clean and dry to help prevent decubital ulcers.
• Give analgesics as needed. Typically, at least 1 to 2 weeks of analgesic therapy is indicated (see Chapter 6).
• Pain, bone instability, and neurologic injury may make it difficult for animals with pelvic fractures to urinate and defecate normally. If necessary, give a mild laxative or stool softener to prevent constipation.
• Empty the urinary bladder regularly by manual expression or catheter drainage, to prevent excessive distention, overflow incontinence, and urine soiling. If a urinary catheter is placed, follow strict aseptic technique to slow the onset of bacterial urocystitis.
• Some patients are able to stand and walk within a few days; however, restrict activity to a cage for 3 to 4 weeks followed by activity limited to only leash walking for 3 to 4 weeks. Avoid slick floors and any uncontrolled activity.
• Physical therapy, in the form of passive range of motion, will lessen the degree of disuse atrophy and loss of joint range of motion.
• If limb adduction is weak as a consequence of ventral pelvic fractures or muscle trauma, use a body sling or towel support around the abdomen as necessary to assist recovery.
Surgical Treatment
Indications
Surgical treatment is indicated for the following injuries:
• Fracture of the ilium with associated fracture of the pubis and ischium creating an unstable acetabulum.
• Severe bilateral fractures of the pelvis or displaced pelvic fractures associated with an additional major orthopedic injury of a pelvic limb, such as hip luxation or fracture of the femur.
• Fractures of the ischium that have an intra-articular component in the acetabulum, or that are suspected of entrapping the sciatic nerve.
• Fracture of the pubis or separation of the pubic symphysis associated with abdominal wall rupture and herniation of abdominal or pelvic organs.
• Gross displacement of the iliac crest or ischiatic tuberosity. These portions of the pelvis serve as the point of origin for the sartorius and semitendinosus and semimembranosus muscles, respectively. Significant distraction of these fragments may result in loss of mechanical advantage and proper function of these muscles.
FRACTURES OF THE ILIUM
Preoperative Considerations
• Fractures of the ilium are usually oblique and are often accompanied by fractures of other regions of the pelvis.
• Perform a thorough neurologic examination (see Chapter 125), particularly with markedly displaced fractures. Damage to the sciatic nerve may be present.
• Surgical repair of fractures of the ilium is generally recommended because most fractures of the ilium are displaced or unstable and the ilial shaft is a component of the weight-bearing portion of the pelvis.
• Precontouring the bone plate to the ilium of an intact pelvis from a cadaver of similar size reduces operating time for the inexperienced surgeon.
• Administer prophylactic antibiotics at the time of anesthetic induction. A first-generation cephalo-sporin such as cefazolin is generally appropriate.
Surgical Procedure
Equipment
• Hand-held retractors such as Myerding retractors and an assistant. Alternatively, Gelpi or Weitlaner self-retaining retractors can be used but generally are not as efficient at making adjustments as an assistant using a hand-held retractor.
• Orthopedic surgical pack with AO-ASIF “clamshell” and Kern bone-holding forceps and Hohmann retractors.
• Bone-plating equipment. Use dynamic compression plates (DCP) or the newer limited contact (LC-) DCP. For complex fractures, reconstruction plates can be used. The latest advance in plating, locking compression plates (LCP) allow the screws to be locked to the plate and are helpful for areas where the bone is weak or subject to failure. Avoid semitubular plates, finger plates, and other thin plates.
Technique
1. Perform a hanging limb prep by preparing the skin for aseptic surgery on the lateral and medial sides of the pelvic limb from the tarsocrural joint to the dorsal and ventral midline and from the mid-lumbar area to the base of the tail.
2. Place the animal in lateral recumbency on a circulating warm water blanket and stabilize the pelvis by placing sandbags under the animal and securing the animal to the table. Rotate the animal table toward the surgeon with towels, inflatable positioners, or a tilting table to improve exposure and reduce back strain of the surgeon.
4. Identify and separate the tensor fasciae latae and middle gluteal muscles. Retract the tensor fasciae latae muscle ventrally, and retract the middle gluteal muscle dorsally to expose the ilium (Fig. 107-3). Subperiosteal elevation of the middle and deep gluteal muscles ventrally from the surface of the ilium exposes the lateral surface of the body of the ilium. Retract the sartorius muscle cranially as needed. Remember that there is little to no plane of dissection at the confluence of sartorius, middle gluteal muscles, and tensor fasciae latae. Sharply incise these muscles where they join and continue the dissection dorsally along the cranial edge of the iliac crest as needed to “roll up” the gluteal to provide adequate exposure of the ilium. The iliolumbar artery is present along the ventral edge of the cranial ilium in these muscles and is usually severed during the muscular dissection. Electrocoagulate or ligate this artery when it is encountered.
a. During exposure of the body of the ilium, it may be necessary to retract or transect branches of the cranial gluteal vein, artery, and nerve that supply the tensor fasciae latae muscle.
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
