I. Hip Arthroscopy
A. Overview
1. Hip arthroscopy is used as a less invasive surgical procedure to treat various intra-articular hip disorders.
2. This surgical technique has an expanding role in the treatment of prearthritic and early arthritic hip disease.
B. Indications
1. Symptomatic acetabular labral tears
2. Early articular cartilage disease (chondral flaps, chondromalacia)
3. Hip impingement disorders
4. Synovitis
5. Loose bodies
6. Ligamentum teres ruptures
7. Diagnostic evaluation of the hip
C. Contraindications
1. Advanced degenerative joint disease
2. Disease states that limit arthroscopic access to the joint (morbid obesity, protrusio, joint ankylosis, heterotopic bone)
3. Intra-articular hip disease (eg, labral tear) associated with major structural abnormalities (developmental hip dysplasia) that require correction of the underlying structural problem
D. Clinical presentation and outcomes
1. Arthroscopic treatment of acetabular labral disease and associated articular cartilage degeneration is the most common indication for hip arthroscopy.
2. Presentation of symptomatic labral tears
a. Patients commonly are active females.
b. Onset of symptoms is insidious or follows minor trauma.
c. Patients commonly present with activity-related anterior inguinal (groin) pain that is also worsened with prolonged sitting, walking, running, and pivoting.
d. Associated bony abnormalities (developmental hip dysplasia and impingement disease) are common.
3. Clinical results associated with arthroscopic treatment vary depending on the diagnosis and condition of the articular cartilage.
a. Good to excellent clinical results are obtained at short-term follow-up in approximately 70% to 85% of the patients treated for labral disease.
b. A guarded prognosis is associated with moderate to advanced (grade IV) articular cartilage disease.
E. Complications
1. The surgical complication rate is low (1% to 3%).
2. Common complications
a. Neurovascular injury
i. Neurovascular complications are a risk because the arthroscopic portal sites are in close proximity to several neurovascular structures (
Table 1).
ii. The lateral femoral cutaeneous nerve is the most "at risk" structure (anterior portal).
iii. The most common neurovascular complication is a transient neurapraxia of the pudendal nerve related to traction.
b. Deep vein thrombosis
c. Instrumentation breakage, articular scuffing
d. Wound hematoma, infection
e. Ankle strain
[Table 1. Proximity of Neurovascular Structures and Arthroscopic Portals]
II. Acetabular and Proximal Femoral Osteotomies
A. General concepts
1. The goals of hip osteotomy are to alleviate pain, enhance function, and prevent or delay secondary osteoarthritis.
2. Various hip disorders can be managed with osteotomy, yet patient selection for surgery is critical to optimize surgical outcomes.
3. Major conditions amenable to osteotomy correction (
Table 2)
a. Developmental hip dysplasia (acetabular and proximal femoral dysplasia)
b. Slipped capital femoral epiphysis (SCFE)
c. Posttraumatic disorders (malunion/nonunion proximal femur, including femoral neck non-union)
d. Legg-Calve-Perthes deformities
e. Selected osteonecrotic lesions
B. Indications/contraindications
1. General indications for hip osteotomy
a. Relatively young physiologic age (<55 years)
b. Prearthritic or early arthritic joint disease
c. Adequate hip motion
d. Correctable structural abnormality
2. Relative contraindications
a. Advanced physiologic age
b. Morbid obesity
c. Major restriction of hip motion
d. Moderate to advanced degenerative joint disease
3. Developmental dysplasia of the hip is a common indication for osteotomy (
Figure 1).
4. Deficient (anterolateral) acetabular coverage of the femoral head is the dominant deformity resulting in structural instability and acetabular rim overload.
a. A reconstructive acetabular osteotomy is the treatment of choice in this clinical situation.
b. The Bernese periacetabular osteotomy (PAO) has been popularized for acetabular reorientation and is now a mainstay of surgical treatment.
C. Surgical procedures
1. Bernese PAO
|
a. |
Advantages |
|
|
i. |
One surgical incision |
|
|
ii. |
Preservation of blood supply to the acetabulum |
|
|
iii. |
Maintenance of posterior column integrity |
|
[Table 2. Characteristics of Common Hip Osteotomies]
|
iv. |
The ability to perform major multidimensional acetabular corrections |
|
|
b. |
Disadvantages |
|
|
i. |
Anterior overcorrection (producing acetabular retroversion and associated femoroacetabular impingement) |
|
|
ii. |
Neurovascular injury |
|
|
iii. |
Intra-articular fracture |
|
2. Chiari salvage osteotomy
a. In the less common clinical situation in which the dysplastic hip is unstable and grossly incongruous, Chiari salvage osteotomy can be considered.
b. The major disadvantage of a salvage osteotomy is that the femoral head is supported by metaplastic fibrocartilage rather than authentic articular cartilage.
3. Proximal femoral varus osteotomy
a. Occasionally, the dysplastic hip has a dominant femoral deformity (coxa valga) or a combined deformity with acetabular dysplasia and severe coxa valga. In such cases, a proximal femoral varus osteotomy may be indicated (alone or in combination with a PAO) to enhance hip stability and congruity.
b. Potential disadvantages of a proximal femoral varus osteotomy
i. Prolonged abductor weakness
ii. Prolonged limp
iii. Shortening of the extremity
4. Flexion, internal rotation proximal femoral osteotomy
a. One indication is residual deformity from a SCFE that causes hip impingement and secondary osteoarthritis.
i. Common clinical signs and symptoms include history of SCFE in adolescence, activity-related hip pain, restricted hip flexion motion, external rotation deformity and obligatory external rotation with hip flexion, and pain with prolonged sitting.
ii. In this setting, a flexion, internal rotation proximal femoral osteotomy can provide major deformity correction and improved function.
iii. Valgus correction can be incorporated into the osteotomy if there is major medial displacement of the epiphysis.
iv. Osteochondroplasty of the femoral head-neck junction augments the osteotomy and minimizes residual femoroacetabular impingement.
[Figure 1. Pelvic osteotomies for hip dysplasia. Dark lines indicate the location of each osteotomy. Each type of osteotomy has theoretic advantages and disadvantages.]
b. Another indication is posttraumatic malunions and nonunions of the proximal femur.
i. For malunions, the osteotomy is designed to correct the specific deformity.
ii. For example, a varus/external rotation intertrochanteric malunion is treated with a valgus/internal rotation intertrochanteric osteotomy.
5. Valgus-producing intertrochanteric proximal femoral osteotomy (Pauwel osteotomy)
a. This osteotomy is another effective way to manage femoral neck nonunion in a young patient (<55 years).
b. This osteotomy converts the vertical shear force across the nonunion into a compressive force by reorienting the nonunion site in a more horizontal position.
D. Clinical outcomes
1. The clinical outcomes of hip osteotomy surgery depend on the type of osteotomy performed and the severity of the underlying intra-articular hip disease.
a. In general, well-established osteotomy techniques provide good to excellent clinical results in 70% to 90% of patients at midterm follow-up.
b. The integrity of the acetabular labrum and condition of the articular cartilage are important prognostic variables in dysplastic hips. Delayed gadolinium-enhanced MRI of cartilage has been used to assess articular cartilage glycosaminoglycan changes in acetabular dysplasia and can be predictive in the prognosis of acetabular reorientation. Low content has been associated with periacetabular osteotomy failure.
2. Total hip arthroplasty after osteotomy surgery can yield excellent clinical results but can be complicated by previous incisions, scar tissue, retained hardware, and residual deformity.
a. Studies demonstrate good clinical results in most patients, yet the procedures can be associated with slightly longer surgical times, increased blood loss, and higher complication rates.
b. Osteotomy procedures should be performed to facilitate future total hip arthroplasty. Specifically, angular deformities of the femur produced by the osteotomy should be avoided.
III. Femoroacetabular Impingement
A. General concepts
1. Femoroacetabular impingement is now recognized as a common cause of hip dysfunction and secondary osteoarthritis.
2. Distinct structural abnormalities produce repetitive impingement between the acetabulum and femoral head-neck junction (
Table 3).
a. Cam impingement (abnormalities that are femoral-based, such as aspherical femoral head, reduced head-neck offset) results in repetitive abutment of the acetabular rim and femoral head-neck junction.
b. Pincer impingement (acetabular-based disorders such as acetabular retroversion, coxa profunda, acetabular protrusion) creates abnormal abutment of the acetabular rim and femoral head-neck junction.
c. Combined cam/pincer deformities are common.
3. These impingement abnormalities result in:
a. Labral degeneration and tears
b. Articular cartilage delamination
c. Secondary osteoarthritis
B. Evaluation
1. History and physical examination
[Table 3. Impingement Disorder Characteristics]
a. Patients with symptomatic hip impingement frequently present with:
i. Activity-related hip pain that is exacerbated by hip flexion activities
ii. Difficulty with prolonged sitting
iii. Mechanical symptoms secondary to labral and articular cartilage disease
b. Physical examination
i. Restricted hip flexion motion and limited internal rotation in flexion is revealed.
ii. The impingement test (flexion, adduction, and internal rotation) usually elicits hip pain.
2. Imaging
a. The AP pelvis view is used to assess acetabular anatomy including version (
Figure 2) and sphericity of the femoral head.
b. The cross-table lateral view (in 15° of internal rotation) is analyzed to assess femoral head sphericity and femoral head-neck offset.
c. MR arthrography provides information regarding the integrity of the articular cartilage and acetabular labrum. The anatomy of the proximal femur is also delineated.
C. Surgical management
1. The surgical management of impingement disease is rapidly evolving and includes arthroscopic, combined arthroscopic and open, and open techniques with surgical dislocation.
2. An open technique with surgical dislocation is the most established strategy for treating impingement disease.
a. Surgical dislocation uses a "trochanteric flip" to provide safe access to the proximal femur and acetabulum.
b. Advantages of the open technique with surgical dislocation
i. Preservation of the blood supply to the femoral head via the deep branch of the medial femoral circumflex artery
ii. Wide exposure of preoperative femoral acetabulum
iii. Ability to perform femoral head-neck junction osteochondroplasty, acetabular rim osteochondroplasty, and labral repair
3. Surgical treatment is indicated in patients with clinical signs and symptoms of impingement disease and a defined structural impingement lesion.
4. Relative contraindications include advanced physiologic age (>55 years), morbid obesity, and moderate to advanced degenerative joint disease.
5. Early to midterm follow-up (2 to 5 years) after surgical dislocation of the hip indicates good to excellent results in approximately 70% to 90% of patients.
a. Labral repair is preferred over labral resection when technically feasible.
b. Results are less predictable in hips with moderate to severe degenerative disease.
6. Potential complications
a. Heterotopic bone formation
b. Trochanteric nonunion
c. Sciatic nerve palsy
d. Osteonecrosis of the femoral head (uncommon)
e. The risk of femoral neck fracture is minimized by limiting the depth of femoral head-neck junction osteochondroplasty to <30% of the diameter of the femoral neck.
7. Use of hip arthroscopy to treat femoroautolabral impingement may be indicated if the process is localized and accessible or when advanced degeneration makes an open technique inadvisable.
IV. Arthrodesis
A. Indications/contraindications
1. Hip arthrodesis is an uncommon procedure that is used to treat advanced hip degeneration in a very specific patient population.
2. The patient must understand the limitations of a successful hip arthrodesis.
[Figure 2. Radiographic assessment of acetabular version. A, Line drawing of an AP view of a hemipelvis, showing a hip with normal version. Note the nearly parallel orientation of the anterior (bold line) and posterior (dashed line) acetabular walls. There is no crossover and the lines converge at the superolateral aspect of the acetabulum. B, Hip with acetabular retroversion. The "cross over" sign, which has been described as an indicator of acetabular retroversion, is present. The anterior aspect of the acetabular rim (bold line) projects laterally to the posterior aspect of the rim (dashed line) at the most proximal aspect of the acetabulum.]
3. Arthrodesis can be considered in patients with the following characteristics:
a. <30 years of age
b. High activity level (eg, manual labor)
c. Severe pain and stiffness
d. Posttraumatic arthritis or end-stage disease associated with previous infection
e. Normal neighboring joints (lumbar spine, contralateral hip, ipsilateral knee)
4. Contraindications to arthrodesis
a. Disease in the neighboring joints (lumbar spine, ipsilateral knee, and contralateral hip)
b. Major limb-length discrepancy (>2.0 cm)
c. Active infection
B. Surgical techniques
1. The goals of surgical treatment are to achieve bone apposition at the fusion site, rigid internal fixation, and early mobilization.
2. The most popular surgical techniques include cobra plating through the lateral approach with a trochanteric osteotomy or plating through an anterior approach to the hip.
3. The arthrodesis position is critical for optimizing function and minimizing deterioration of the neighboring joints. The preferred position is 25° to 30° of hip flexion, 0° to 5° of adduction, and 5° to 10° of lower extremity external rotation.
C. Results
1. Hip arthrodesis achieves lasting pain relief and satisfactory clinical results in most patients.
2. The survivorship of arthrodesis can be limited by symptomatic degenerative disease of the neighboring joints.
a. The lumbar spine, ipsilateral knee, or contralateral hip can demonstrate joint degeneration.
b. Low back pain and instability and osteoarthritis of the ipsilateral knee are the most common problems.
c. Occasionally, hip fusion conversion to total hip replacement is needed.
3. Conversion of a hip arthrodesis to total hip arthroplasty provides good clinical results in most patients.
a. Trochanteric osteotomy is frequently necessary for surgical exposure.
b. Rehabilitation is prolonged because of profound hip abductor weakness and the associated limp.
Top Testing Facts
1. Acetabular labral disease is commonly associated with hip impingement and developmental dysplasia structural abnormalities.
2. Hip osteotomy surgery is contraindicated in patients with major restriction of hip motion and/or advanced joint deterioration.
3. Advantages of the PAO include one surgical incision, maintenance of the posterior column, preservation of blood supply to acetabulum, and the ability to perform major multiplanar acetabular corrections.
4. Overcorrection or retroversion of the acetabulum with a PAO can produce secondary femoroacetabular impingement.
5. Delayed gadolinium-enhanced MRI of cartilage can be used to assess articular cartilage glycosaminoglycan content in acetabular dysplasia; low content has been associated with periacetabular osteotomy failure.
6. Cam impingement refers to femoral-based deformities (aspherical femoral head or reduced head-neck offset) that result in repetitive abutment of the acetabular rim and femoral head-neck junction.
7. Pincer impingement describes acetabular-based deformities (acetabular retroversion, coxa profunda, acetabular protrusio) that create abnormal abutment of the acetabular rim and femoral head-neck junction.
8. The technique of surgical hip dislocation with a "trochanteric flip" is based upon preservation of blood supply to the femoral head via the deep branch of the medial femoral circumflex artery.
9. Hip arthrodesis survivorship can be limited by symptomatic degenerative disease of the neighboring joints (lumbar spine, ipsilateral knee, contralateral hip).
10. The optimal position for hip arthrodesis is 25° to 30° of flexion, 0° to 5° of adduction, and 5° to 10° of external rotation.
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