Chapter 57 Hip luxation

Question 1

The hip joint is a ball and socket joint stabilized by different structures. Name the primary and
secondary stabilizing structures.

Answer 1

Primary; ligamentum teres femoris or round ligament, joint capsule, dorsal acetabular rim
Secondary; acetabular labrum, hydrostatic pressure caused by joint fluid, peri-articular muscles

Question 2

A. What is the most common direction of luxation of the hip joint and what is the relative occurrence
percentage?
B. The luxation of the femoral head in ventral or caudal direction typically occurs when a traumatic
incident forces the pelvic limb into abduction, it also may be associated with a certain type of fracture,
which fracture?

Answer 2

A. The craniodorsal luxation, 75% of the hip luxations.
B. Avulsion fracture of the greater trochanter

Question 3

List at least 5 clinical findings common with craniodorsal luxation of the hip joint?

Answer 3

1. Pain in the hip region
2. Lameness (usually non-weight bearing initially)
3. External rotation and adduction of the affected limb
4. Asymmetry of the hips due to dorsal displacement of the greater trochanter
5. Increased distance between the greater trochanter and the ischiatic tuberosity
6. Apparent shortening of the affected limb
7. Crepitus of the hip joint

Question 4

Joint reduction should be performed soon after injury to minimize destruction of cartilage and before
muscle spasticity and fibrosis prevent easy relocation. What is the recommende maximum time after
trauma when a hip luxation should be reduced?

Answer 4

Within 72 hours after trauma

Question 5

Closed reduction of the luxated hip joint is more likely to be successful if performed in the first few
days after luxation. Which factors negatively influence the outcome of the closed reduction?

Answer 5

1. Intra-articular fracture
2. Muscle contracture
3. The presence of soft tissue or heamatoma in the acetabulum
4. Inflammation of the lig. Teres femoris
5. Peri-articular fibrosis

Question 6

Reluxation has been reported in more than 50% of the cases following closed reduction alone.
Therefore, the application of closed or open techniques to stabilize the joint is recommended after
closed reduction. List three techniques after closed reduction and explain them, i.e., why do they
work?

Answer 6

1. For craniodorsal luxation; Ehmer Sling; figure of eight bandage. The Ehmer sling flexes the hip
   joint and abducts and internally rotates the femur to position the femoral head within the
   acetabulum.
   è Reluxation occurs most often during external rotation of the femur and extension of the hip
   joint.
2. For ventral luxations; Hobbles; bandage at the hocks or stifles to prevent limb abduction.
   è Ventral luxations typically occur because of excessive force during abduction.
   è However, many ventral luxations are managed successfully without Hobbles
3. For caniodorsal luxation; Ischioilial pinning; Insertion of a Steinmann pin from ventral to the
   ischium, passed cranially over the femoral head and embedded into the wing of the ilium
   cranially.
   è Prevents dorsal movement of the femur
   è Study of 21 dogs showed that reduction was maintained in 73%
   è This study also showed a complication rate of 32%
4. External Skeletal Fixation
5. Trans-articular pinning

Question 7

What is the reported success rate for open reduction and stabilization?
A. 55%
B. 65%
C. 75%
D. 85%

Answer 7

Answer C

Question 8

What factors should be considered when choosing an appropriate surgical technique for stabilizing hip
luxations? List at least 5.

Answer 8

1 Patients activity level
2 Patients body weight
3 The direction of the luxation
4 The extent of the injury to the cartilage and joint capsule
5 Concurrent injuries
6 Economic constraints
7 Surgeon preference

Question 9

Which of the following statements are true considering the ‘toggle rod stabilization’ technique?
A When a toggle rod technique has been applied an Ehmer Sling is advisable, since it will reduce the
amount of reluxations.
B The use of ‘home made toggles’ is not advisable, because they cause higher rates of relaxation
compared to commercially available toggles.

Answer 9

A False, The success of a Toggle rod stabilization appeared unaffected by the postoperative use of an
Ehmer Sling
B True, Significant variability in mechanical strength was identified in ‘home made toggles’ depending
on how they were configured and how they were oriented within the pelvis. Only one of four possible
orientations was considered acceptable.

Question 10

List at least 7 other surgical stabilization techniques for hip luxations.

Answer 10

1 Capsulorraphy
2 Prosthetic Capsule Technique
3 Transposition of the Greater Trochanter
4 Transarticular pinning
5 Fascia Lata loop stabilisaton
6 Transposition of the sacrotuberous ligament
7 Extra-articular Iliofemoral suture
8 Triple Pelvic Osteotomy
9 Total hip arthroplasty
10 Femoral head and neck excision