Coxofemoral Joint
Hip dysplasia
Legg-Calve-Perthes disease
Hip luxation
Iliopsoas muscle/tendon strain
Osteochondritis dissecans of femoral head
Trauma/fractures
Hip dysplasia
Signalment
Breeds – Large and giant breeds of dogs
Gender – Males may be predisposed, but females are commonly affected.
Age – Initial clinical signs may occur between 4 and 12 months of age. Dogs often clinical improve, but may not. Signs often occur in later life as a result of continued progression of osteoarthritis, or in some cases, hip luxation.
Etiology - Hip dysplasia is an abnormal development of the hip joint, usually bilateral, that occurs primarily in medium and large breed dogs. The causes are multifactorial and include genetic predisposition, rapid growth rate, and diet.
History
Owners may report dogs have difficulty rising, decreased activity level, ‘bunny-hopping’ gait, and loss of muscle mass in the hindquarters. Difficulty jumping up or negotiating stairs may also be reported.
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Clinical Findings
Dogs may have a "bunny hopping gait", difficulty rising, difficulty climbing stairs, and muscle atrophy, especially of the gluteal muscles. Because most cases have bilateral involvement, the gait may have a "waddling" type appearance. In young dogs, palpation of the hip joint(s) may indicate laxity (subluxation), by doing an Ortolani test. In younger and older dogs, there may be pain with hip extension, limited hip extension and abduction, and crepitus with joint manipulation. Dogs with hip luxation may have displacement of the greater trochanter and severe crepitus and pain. In cases of hip dysplasia with hip luxation, reduction of the hip is not recommended because of severe remodeling of the hip joint and great probably of re-luxation.
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Diagnostics
Radiographs may appear normal win very young dogs, although some degree of subluxation may be evident. In young dogs, PennHIP is the best method to quantify hip joint laxity and to obtain a distraction index which tells the likelihood of developing osteoarthritis in the future. This technique may be performed as easy as 16 weeks.
As the condition progresses, radiographs show varying degrees of osteoarthritis with remodeling of the femoral head and acetabulum. The rate of progression of hip dysplasia varies between individuals and is difficult to predict. Some dogs may have degenerative changes by 9 months of age, while many individuals develop advanced OA in mid-life or later.
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OFA evaluation can be performed at any age, although a definitive score will not be given until 2 years of age, when 95% of dogs with hip dysplasia will have radiographic signs. This DOES NOT mean that hip dysplasia cannot be diagnosed with OFA-like views before 2 years of age; in fact it may usually be diagnosed before skeletal maturity with clinical and radiographic evaluation
Treatment Options
In young dogs, there are a number of surgical procedures that are designed to change the joint alignment in order to improve joint stability and slow the progression of OA. The most common of these procedures are the triple pelvic osteotomy (TPO) and juvenile pubic symphsiodesis. Triple pelvic osteotomy is performed on dogs that have shown early signs of hip dysplasia and have joint laxity, but have not progressed to the point of having radiographic evidence of OA. Most dogs that fit these criteria are between 4 and 10 months of age. They usually have atrophy of the gluteal and thigh muscles. The technique involves making 3 osteotomies in order to change the orientation of the acetabulum. A bone plate is used to stabilize the ilium. Postoperatively, activity is restricted for 4 to 6 weeks to allow for bone healing. A similar procedure, the double pelvic osteotomy (DPO) has similar inclusion criteria, but only two osteotomies are performed rather than three. These procedures appear to slow the progression of osteoarthritis and reduce clinical signs, but there will be some progression of arthritis.
Juvenile pubic symphysiodesis is performed in dogs between 16 and 20 weeks of age that are considered to be at risk for developing hip dysplasia. The pubic symphysis is surgically damaged, causing it to fuse and alter pelvic growth. These puppies are often clinically normal at the time of the procedure and the surgical trauma is minimal. This technique is often helpful in reducing the progression of osteoarthritis in dogs with mild to moderate hip joint laxity, but there may not be enough correction in pelvic structure if the laxity is severe.
Total hip replacement involves replacing the acetabulum with an acetabular prosthesis, and replacing the femoral head with a femoral prosthesis implanted in the medullary canal of the femur. Most systems used today are bone ingrowth implants, although it may be necessary to secure the prosthesis with bone cement in some situations. The most common postoperative complication is hip luxation so post-operative care and muscle strengthening are important, especially since there is often preexisting muscle atrophy. Close confinement is enforced for the first postoperative month when the dog is unsupervised. During early ambulation, the dog is supported with a sling to prevent abduction of the limb and dislocation of the prosthesis. Muscle strengthening can be achieved using controlled walking, treadmill activity and sit to stand exercises. The duration of these activities is gradually increased during the first 2 months. Balance and proprioception reeducation may also be important. Dogs are restricted to leash walking, with no running or jumping for the first 3 postoperative months to reduce the chances of implant loosening or dislocation. In addition to prosthesis luxation and loosening of the prosthesis, infection and fracture of the femur may occur. Prognosis is good to excellent in most cases. A deterioration in limb use may signal loosening of the implant or the onset of another problem, such as a cranial cruciate ligament rupture.
Femoral head and neck ostectomy (FHO) is another salvage procedure that may be performed in dogs with advanced hip dysplasia and severe clinical signs that are not able to be managed with conservative treatments. Many small and medium-sized dogs do well with this procedure if it is done correctly and there is adequate post-operative rehabilitation. Larger dogs often have altered gait and weakness following this procedure, especially if the rehabilitation is not adequate. However, it is less expensive than a total hip and clinical signs of pain may be alleviated.
If surgery is not an option or dogs have mild or intermittent signs of hip dysplasia, dogs may be treated conservatively. This includes a combination of NSAIDs, other pain medications as needed, Disease Modifying Osteoarthritic Agents (DMOAs), rehabilitation techniques, diet and exercise, and is discussed in the section on OA. For dogs having pain that is not adequately managed by conservative methods, total hip replacement (THR) or femoral head and neck ostectomy (FHO) are salvage surgical options. Both procedures eliminate the normal joint, thus eliminating the pain. In general, THR is not an option after an FHO has been performed.
Legg-Calve-Perthes disease
Signalment
Breeds – Toy and miniature breeds of dogs, with Cairn terriers, Manchester terriers, Chihuahuas, dachshunds, Lhasa apsos, pugs, Yorkshire terriers, West Highland white terriers, miniature poodles, toy poodles, and miniature pinschers identified to be at greatest risk.
Gender – No gender predilection.
Age – Dogs usually develop lameness between 5 and 10 months of age
Etiology - Legg Calve Perthes disease is noninflammatory aseptic necrosis of the femoral head and neck that occurs in small breed dogs. The etiology is unknown, although a genetic component has been identified in some breeds.
History
The disease is often well under way before clinical signs are noticed by the owner. Dogs may be irritable and resist jumping up, especially on to furniture. They may also resist climbing stairs. Lameness generally progresses from barely perceptible to completely nonweight-bearing.
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Clinical Findings
Lameness is generally quite severe by the time the dog is brought to the veterinarian. As the condition progresses, pain may be elicited with extension and abduction of the hip joint. Atrophy of the muscles on the affected side is generally noticed within two weeks of onset.
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Diagnostics
Radiographs generally confirm the clinical diagnosis. Initially areas of lysis and demineralization may be present in the subchondral region of the femoral head and in the femoral neck. As the condition progresses, obvious collapse of the femoral head and neck may be apparent. Later in the course of the disease, evidence of re-mineralization and bone healing may be present. Secondary changes of osteoarthritis include osteophytes, flattening of the femoral head, and osteophytes along the dorsal acetabular rim.
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Treatment Options
Because the condition is not generally recognized until there are severe radiographic signs, the treatment of choice is generally Femoral Head and Neck Ostectomy. Prognosis is good after surgery, provided appropriate rehabilitation is performed beginning immediately after surgery. Early active use of the limb is encouraged to prevent excessive fibrosis and loss of motion of the pseudoarthrosis. Adequate analgesia throughout the rehabilitation program is a key factor for a successful outcome. Cryotherapy can also help reduce pain and early inflammation. Passive range of motion exercises are begun during anesthetic recovery and continued daily until the animal is using the limb well. Assisted weight bearing activity is initiated the day after surgery. Active weight-bearing activities are progressed to higher levels as tolerated by the animal, to improve limb use and muscle strength.
Hip luxation
Signalment
Breeds – Any breed is susceptible, but larger breeds are most frequently affected
Gender – No predilection
Age – Any age
Etiology - Trauma. Many cases occur as a result of automobile trauma. Because of this, careful evaluation of the thoracic and abdominal structures is important to detect cardiac arrhythmias, pneumothorax, pulmonary edema, diaphragmatic hernia, ruptured urinary tract, or abdominal hemorrhage. Although hip luxation secondary to severe hip dysplasia occurs with minimal trauma (sometimes as mild as bumping into a chair), this discussion will center on traumatic hip luxations.
History
There is an acute onset of severe lameness as a result of trauma. Caution should be taken to assess the entire patient for other injuries.
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Clinical Findings
Dogs are usually nonweight-bearing lame. Craniodorsal luxation is by far the most common. The stifle and foot are externally rotated and the limb is usually held in a flexed position. There is pain and crepitus with manipulation. When evaluating anatomical differences, the greater trochanter is located on above a line drawn from the dorsal aspect of the wing of the ilium and the tuber ischium. There is greater space between the greater trochanter and tuber ischium as compared to the contralateral normal limb (thumb notch test). In addition, when the dog is placed in dorsal recumbency and both pelvic limbs are extended, the affected limb is shorter, and when the pelvic limbs are pulled forward by flexing the hips, the affected limb is longer. Ventral luxation sometimes occurs, with the femoral head trapped in the obturator foramen. Dogs are lame and the greater trochanter is located distally and more medially as compared to the contralateral normal limb.
Diagnostics
Radiographs confirm the clinical diagnosis. Radiographs may also show bone fragments associated with the damaged ligament of the head of the femur.
Treatment Options
Closed reduction is attempted first. The animal should be anesthetized when safe to do so, and traction should be applied by hanging the limb (the body should be lifted from the table) from a ceiling hook or IV pole for 5-10 minutes to fatigue the muscles. A towel or sling is placed around the abdomen to provide dorsal countertraction. The person performing the reduction grasps the limb, adducting and externally rotating the femoral head. Constant traction is applied until the greater trochanter is below a line between the dorsal wing of the ilium and the tuber ischium. Then, one hand applies pressure to the greater trochanter to push the femoral head into the acetabulum while simultaneously internally rotating and abducting the femoral head. If successful, there is a distinct feel as the reduction occurs. There may be some crepitus felt during the reduction. Digital pressure is maintained on the greater trochanter while rotating the hip to express fibrin and other debris from the articulation and to re-establish the fluid seal between the femoral head and acetabulum for approximately 5 minutes. The pressure on the greater trochanter is released, and the hip is placed through passive range of motion and the integrity of the hip is gently tested. If the hip immediately luxes, surgical stabilization is usually necessary. If the hip maintains reduction, an Ehmer sling is placed. Radiographs should be made post-reduction to be certain that the femoral head has been completely reduced. It is quite common to think that the hip has been reduced, only to find that it was only partially reduced. Additional attempts may be tried. If closed reduction is successful, the hip is maintained in the Ehmer sling for 2 weeks. If attempts of closed reduction are unsuccessful, then open reduction and stabilization is recommended.
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If a ventral hip luxation is present, the same distraction process is carried out under anesthesia. To reduce the hip, the limb is abducted, the hip is externally rotated, and the limb is pulled distally. Closed reduction is generally successful. To prevent recurrence while the joint capsule is healing, hobbles are placed on the rear limbs to prevent abduction of the limb.
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If closed reduction is not successful for a craniodorsal hip luxation, surgical stabilization techniques include capsulorrhaphy, toggle pin fixation, prosthetic joint capsule, antirotational suture, and displacement of the greater trochanter caudally and distally. The limb is kept in an Ehmer sling after surgery while the joint capsule begins to heal.
Iliopsoas muscle/tendon strain
Signalment
Breeds – Generally working and sporting dogs, and medium to large breeds in general.
Gender – No gender predilection
Age – Usually middle aged to older
Etiology - The iliopsoas muscle or tendon may be stretched or torn under extreme circumstances. True iliopsoas tendon damage is likely over diagnosed. Most causes of iliopsoas region pain are secondary to other underlying pelvic limb conditions. With most orthopedic conditions of the stifle or hip, the joint is painful in extension. Therefore, dogs are reluctant to fully extend the hip joint, leading to adaptive shortening of the iliopsoas muscle. When there is sudden, powerful extension of the hip, there may be a mild muscle strain which results in pain and discomfort. A primary underlying cause of lameness should be sought in such cases.
History
Dogs are presented with pain, lameness, and reluctance to perform if they are a working or sporting dog.
Clinical Findings
Dogs may have lameness. Extension of the hip and internal or external rotation puts stress on the insertion of the iliopsoas on the lesser trochanter. Palpation of the groin area very proximally and medially may cause extreme muscle fasciculations of the pectineus and iliopsoas muscles. Palpation of the iliopsoas insertion on the lesser trochanter is accomplished by palpating caudal to the pectineus muscle; the lesser trochanter is located on the caudal aspect of the medial femur. Alternatively the iliacus muscle may be painful at its origin on the ventromedial border of the body of the ilium. Caution should be exercised to be certain that the sartorius muscle is not the cause of pain; it is located further cranially and may be the source of discomfort in some cases.
Diagnostics
In addition to palpation and manipulation of the area, ultrasound of the region of the iliopsoas may give information if there has been muscle or tendon damage. Often, there are no lesions visible. Care should be taken to do a thorough orthopedic examination of the pelvic limbs and caudal spine to evaluate for other causes of pelvic limb lameness that may result in biomechanical changes, inducing excessive stress to the iliopsoas.
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Treatment Options
Rest, cryotherapy, stretching and massage of the affected areas is usually successful. Recurrence is frequent, especially if the period of rest is insufficient or there is a primary underlying cause of pelvic limb lameness that is not addressed. Extracorporeal shockwave treatment may be beneficial, and therapeutic laser has also been used.
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Severe cases or cases that are non responsive to conservative therapy may be treated by tenotomy of the tendon from the lesser trochanter.
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Osteochondritis dissecans of femoral head
Signalment
Breeds – Large and giant breed dogs
Gender – Males are predisposed, but females also affected
Age – Generally noted from 4 to 9 months of age
Etiology - Abnormal endochondral ossification of the deep layers of articular cartilage results in focal areas of thickened cartilage that are prone to injury. In the absence of excessive stress, the lesion may heal. However, further stress on the cartilage may result in a cartilage flap. This condition is termed osteochondritis dissecans (OCD). Although osteochondrosis and osteochondritis dissecans are common in other joints, especially the shoulder, its occurrence in the hip is rare. Other causes of lameness should be carefully evaluated.
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History
Mild to moderate lameness, decreased activity
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Clinical Findings
Mild to moderate lameness, atrophy of the pelvic limb muscles, pain may be elicited with extension of the hip.
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Diagnostics
Generally diagnosis suspected on orthopedic exam and confirmed with a V-D radiograph of the hip. It is likely that a CT will be necessary to confirm a diagnosis of OCD of the femoral head.
Treatment Options
Removal of cartilage flap with an arthrotomy or arthroscopy, curettage of subchondral bone, change diet to a large breed growth diet, nonsterodal anti-inflammatory medication, rehabilitation
Trauma/fractures
Signalment
Breeds – Any breed
Gender – No gender predilection
Age – Any age
Etiology – Trauma. Many cases occur as a result of automobile trauma. Because of this and the fact that the pelvic limb is affected, careful evaluation of the thoracic and abdominal structures is important to detect cardiac arrhythmias, pneumothorax, pulmonary edema, diaphragmatic hernia, damage to the urinary system, or internal hemorrhage. Fractures of the acetabulum, femoral head, neck and greater trochanter are possible. Capital femoral physeal fractures are common in skeletally immature dogs.
History
Often owners witness trauma, such as a fall, hit by automobile, or other sudden traumatic event that results in sudden onset of severe lameness.
Clinical Findings
Fractures of the hip joint result in severe lameness and pain on manipulation and crepitation.
Diagnostics
Radiographs are generally diagnostic, but CT evaluation may give additional details.
Treatment Options
Most fractures of the hip joint require internal fixation to restore joint anatomy and minimize arthritis development.
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Information regarding fractures of the acetabulum may be found in the trauma section of the pelvis.
Femoral head fractures and capital femoral physeal fractures are generally managed with divergent pins and/or a screw from the base of the greater trochanter to the femoral head. In some cases it may be necessary to do a trochanteric osteotomy to gain adequate access for the repair.
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Greater trochanter fractures are repaired with a pin and tension band technique.
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Capital femoral physeal fractures are common in skeletally immature dogs. Repair is with divergent pins from the base of the greater trochanter to the femoral head. It is important to do the repair as soon as safely possible due to the risk of demineralization of the femoral neck and an "apple core" appearance that results in poor reduction of the capital epiphysis. Further, the age of the patient at the time of injury is important. Dogs less than 6 months of age have a much greater chance of developing moderate to severe osteoarthritis because of premature closure of the growth plate, femoral head/acetabulum incongruity because of the differential in growth between the two components of the hip joint, and subsequent joint incongruity. Alternatively, if surgery is not performed until later or if arthritis development affects limb use and mobility, a femoral head and neck ostectomy or total hip replacement may be performed.
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