Hip

General

Problems of the hip account for about 15% of the practice of orthopedists. Many hip problems in adults have their origin during growth.

Development

Ossification of the ischium, ilium, pubis, femoral shaft, and distal femoral epiphysis occurs before birth. The femoral head ossifies between the second and eighth postnatal months (Fig. 1) and fuses with the neck between 15 and 21 years in boys and one year earlier in girls.

Figure 1. Ossification of proximal femur This sequence shows ossification in the normal child. Redrawn from Tönnis (1984).

Growth of the upper femur occurs not only in the capital epiphysis and trochanteric apophysis but also along the neck of the femur (Fig. 2). Growth from the triradiate cartilage is a major contribitor to acetabular development (Fig. 3). The deformities caused by trauma are site-specific (Fig. 2).

Figure 2. Pelvic growth This child had a phosphorolized oil dietary supplement as a child. Growth patterns are shown. Note the growth that occurs in the triradiate cartilage (orange arrow) and upper femur (red arrow). Courtesy I. Ponseti.

Figure 3. Proximal femoral growth Note that growth (red arrows) occurs at many sites about the upper femur, including appositional growth of the femoral neck. Damage to the greater trochanteric apophysis from curettage for a bone cyst (yellow arrow) or from reaming to place an IM nail (orange arrow) causes a reduction in width and functional elongation of the femoral neck.

Most growth of the acetabulum occurs from the triradiate cartilage. Closure will cause severe progressive dysplasia. Additional growth of the acetabulum occurs from the acetabular epiphysis. This growth is especially important late in childhood and during adolescence.

Damage to these growth centers, either from trauma or as a complication of treatment, is a common source of deformity and disability. The upper femur is very susceptible to vascular or epiphyseal injury.

Vascularity

Disturbances in blood supply to the upper femur are a common cause of many serious deformities and subsequent disability.

The femoral head may receive blood through the ligamentum teres, epiphyseal vessels, or metaphysis. The femoral head in the infant is supplied by epiphyseal vessels and vessels that traverse the epiphyseal plate (Fig. 4). These transphyseal vessels disappear as ossification develops in the femoral head. Circulation in the child is primarily through the metaphyseal vessels. Only in late childhood and adolescence do the ligamentum teres vessels make a significant contribution. After closure of the capital physeal plate, the metaphyseal vessels contribute to the circulation.

Figure 4. Vascularity of the femoral head In infancy, transphyseal vessels are often present (red arrow). In childhood, the femoral head is supplied by the lateral retinacular vessels that must traverse the joint (yellow arrow). From Chung (1976).

During most of childhood, this vascular supply is provided by two anastomotic rings formed by the medial and lateral circumflex vessels (Fig. 5). The pattern of distribution is variable, and deficiencies may contribute to the development of avascular necrosis.

Figure 5. Vascularity of the femoral head Note that the proximal femur is supplied by an arcade of vessels that arise from the profundus femoral artery.

Biomechanics

Loading within the joint is affected by the load-bearing area (Fig. 6). Increased loading is prominent when the hip is subluxated or shallow. Increased loading leads to osteoarthritis in adult life.

Operative procedures, especially osteotomies of the pelvis and femur, dramatically affect the biomechanics of the hip. The hip joint normally carries about four times its body weight. Hip joint loading is reduced by varus femoral osteotomy or by medializing the joint, as done in the Chiari osteotomy. When reconstructing a hip, try to achieve as normal an anatomy as possible.

Figure 6. Biomechanics of the hip In the normal hip, loading (green arrow) is low and well distributed. In dysplasia, loading is concentrated (red arrow), resulting in eventual cartilage degeneration.

Nomenclature

Hip terminology is reasonably straightforward (Fig. 7). The most significant recent change was the replacement of the term congenital with developmental in hip dysplasia. Congenital hip disease (CDH) thus becomes developmental hip dysplasia (DDH). Hip disorders caused by muscle disorders secondary to neurologic disorders such as cerebral palsy are called neurogenic dysplasia of the hip (NDH). The term dysplasia is a broad term covering disorders that may involve the acetabulum, upper femur, or both elements

Figure 7. Nomenclature for deformity These terms are commonly used to describe various patterns of hip deformity.

Evaluation

A thorough evaluation of the hip is important due to the vulnerability of the hip joint to damage, especially from impaired blood supply. Delays in diagnosis of DDH, septic arthritis, and slipped epiphysis are relatively common and sometimes result in joint destruction. The deep position of the hip joint makes evaluation more difficult than most extremity joints such as the knee or ankle. This, together with its tenuous vascularity, places the hip at special risk.

History

Is there a family history of hip problems? DDH is familial. Has the child complained of pain? Night pain suggests a neoplastic origin. Remember that hip pain may be referred to the knee (Fig. 8). Has the child limped? Were there systemic signs? Has the problem been getting worse or has it plateaued? Be certain to rule out septic arthritis and slipped epiphysis as acute disorders and DDH as a long-term problem.

Figure 8. Hip pain referred to knee The obturator nerve supplies articular branches to the hip and cutaneous coverage about the knee. Hip disorders may present with knee pain.

Physical Examination

Observation Does the child appear ill? Is there spontaneous movement of the limb? Pseudoparalysis is common in trauma and infections. Does the child limp? Limping from hip problems is usually antalgic or due to an abductor lurch.

Palpation Palpate for tenderness over the bony prominences. Tenderness is often found in the adolescent with bursitis, tendonitis, or overuse syndromes. By determining the point of maximum tenderness exactly, a presumptive diagnosis can often be made.

Range of Motion Hip disorders often result in loss of motion. Inflammatory disorders usually cause a reduction in internal hip rotation early on and eventually flexion and adduction contracture of the hip.

Hip rotation Assess with the child prone. Assessing the range of medial rotation is a valuable screening test (Fig. 9). The finding of asymmetric hip rotation is abnormal and indicates the need for a radiograph of the pelvis.

Figure 9. Hip rotation test Position the child prone with the knees flexed to 90°. Rotate the hips internally and note any guarding and the extent of rotation. Asymmetry of rotation is usually abnormal. In this child with Legg-Calvé-Perthes Diseaseon the left hip, rotation was limited compared to the normal right hip.

Flexion Detect the presence of a contracture using the Thomas or prone extension test (Fig. 10). The prone extension test is most accurate, especially in children with neuromuscular disorders.

Abduction–Adduction Assess while stabilizing the pelvis with one hand.

Figure 10. Hip flexion contracture assessment The Thomas test (left) is performed with the contralateral hip flexed. Extend to measure the degree of contracture. The prone extension test (right) is performed with the child prone. Gradually extend the hip until the hand on the pelvis begins to rise. The horizontal-thigh angle indicates the degree of contracture.

Trendelenburg Test

Assess an abductor lurch using the Trendelenburg test (Fig. 11). Ask the child to lift one leg at a time. The pelvis should rise on the elevated side. A drop of that side is a positive sign and suggests that the abductor mechanism is weak on the opposite side. This lurch may be due to weakness of the muscles, a change in shape of the upper femur, or inflammation of the joint.

Figure 11. Trendelenburg test This girl has DDH with weakness of the left hip abductors. When standing on her right leg, right hip abductors contract to elevate the left pelvis to maintain the head centered over the body (green lines). When standing on the weaker left leg, abductor weakness allows the right pelvis to fall (blue arrow). She must then shift her weight over the left leg (red lines).

Laboratory Studies

A CBC and an ESR and CRP are often helpful in evaluating hip disorders. The ESR and CRP are useful in differentiating septic arthritis from toxic synovitis. Infections usually elevate the ESR above 25–30 mm/hr. Toxic synovitis causes only a slight elevation in the ESR and CRP. Hematologic disorders such as leukemia and sickle cell disease may cause pelvic pain.

Hip Joint Aspiration

The aspiration of the hip is the most certain method of establishing the diagnosis of septic arthritis. Aspirate the joint promptly if the diagnosis of septic arthritis is seriously included in the differential. Although a negative aspirate (even when documented by an arthrogram) is not absolutely definitive, it is highly suggestive that the problem is not within the joint.

Delays in diagnosing septic arthritis may be catastrophic because it jeopardizes the vascularity to the femoral head and articular cartilage. Joint aspiration does not affect bone scans and should not be delayed by plans to perform imaging procedures.

Imaging

Imaging is required to evaluate hip disorders in children. Imaging is the only way to establish a prognosis. The vast majority of hip problems in children can still be managed adequately by careful examination and conventional radiographs.

Conventional radiography Evaluate most hip problems with conventional radiography. Except for the initial study, use a gonad shield. Obtain a single AP study (Fig. 12). Several useful measures may be made from this simple study (Fig. 13)

Figure 12. AP x-ray of pelvis Much can be learned from this simple study. The right hip is normal. Acetabular dysplasia is present on the left. Note the triangular shape of the tear drop (red arrows). Note that the joint space (orange line) is widened. Shenton's line (green lines) is disrupted. The sourcil, or acetabular roof (yellow arrows), is sclerotic. The left hip joint is slightly higher and more laterally positioned than the normal side.

Figure 13. Center-edge (CE) angle This child has a normal left hip with a CE angle of 30°. The right hip is aspherical and subluxated, and the CE angle is 10°. Note that measures are made with the pelvis level (white line).

Note any asymmetry in ossification of the pelvis. A painful condition such as an osteoid osteotomy results in hemideossification (Fig. 14). Be aware of the situations in which false negative studies are commonly misleading. A negative study does not rule out DDH in the neonate or an early septic arthritis. An AP radiograph may not show a mild slipped capital femoral epiphysis (SCFE).

Figure 14. Hemideossification Note the bone loss of the left hemipelvis (red arrow) due to an osteoid osteoma (yellow arrow) of the proximal femur.

Add other views as necessary. The frog-leg lateral allows comparison of both upper femora. The true lateral is useful in assessing the degree of slip in SCFE, the degree of involvement in Legg– Calvé–Perthes disease, or anterior coverage in DDH (Fig. 15).

Figure 15. Lateral X-rays of the proximal femur Frog-leg lateral (red arrow) is only an oblique view. A true lateral (yellow arrow) requires special positioning but provides more information, as it is made at right angles to the AP view. Note the lack of anterior coverage (red arrow).

Useful special views include the abduction––internal rotation study for hip dysplasia (Fig. 16), maximum abduction and adduction views for assessing hinge abduction problems, and anteversion studies. Femoral anteversion measurement is seldom necessary.

Figure 16. Abduction internal rotation (AIR) view The resting position (red arc) shows the hip in a 14-year-old child with cerebral palsy. The hip is subluxated (orange lines), and Shenton's line (green arc) is disrupted (red arc). The AIR view (yellow arrow) shows improved congruity and less subluxation and restoration of Shenton's line.

The load-bearing area of the hip significantly affects its longevity. A reduction in this area may be due to one or more of the following factors:

Simple hip dysplasia The hip joint is either maldirected or shallow. Both reduce contact area. The depth of the acetabulum is often assessed by the CE angle. This angle increases during childhood as the joint ossifies. At the end of growth, values are like those of adults, with a normal range of 25°–45°. Features of the normal hip are used as a basis for assessing deformity (Fig. 17) and planning reconstruction.

Figure 17. Normal measurements These are measurements of the normal adolescent hip.

Incongruity reduces contact area The femoral head is normally round and matches the shape of the acetabulum (Fig. 18).

Figure 18. Congruity Congruity of the hip may be either spherical or aspherical and congruous or incongruous. Incongruity (red) results in areas of excessive load, causing excessive cartilage wear and eventually osteoarthritis.

An aspherical femoral head is usually due to vascular problems. In the young child, the acetabulum usually remodels to become congruous, and the hip becomes aspherical and congruous (Fig. 19). If acetabular remodeling fails to occur, the hip may be aspherical and incongruous—a bad combination.

Figure 19. Aspherical congruity This deformity resulted from Legg-Calvé-Perthes Diseaseduring middle childhood. The head became flattened and the acetabulum remodeled (red arrows) to become congruous.

Displacement of the femoral head The relationship between the femoral head and acetabulum is normally congruous. If the head is displaced, it becomes subluxated. If all cartilage contact is lost, the joint is dislocated.

Ultrasonography (US) Ultrasound studies are of greatest value when readily available and performed by an orthopedist in conjunction with the overall evaluation. Cost, restricted access, and operator inexperience may limit value. Ultrasound's greatest potential usefulness is in assessing DDH in early infancy. Assessing joint effusion, localizing abscesses, and assessing the severity of SCFE, head size in LCP disease, and neck continuity in coxa vara are other applications. This imaging technique is underutilized in North America.

Scintigraphy Bone scans (BS) are useful in localizing inflammatory processes about the pelvis (Fig. 20)  and in assessing the circulation of the femoral head. Order high-resolution or pinhole-collimated AP and lateral scans of both proximal femora when assessing avascular necrosis (AVN). The bone scan is useful in confirming a preslip and assessing bone tumors.

Figure 20. Imaging options This bone scan shows inflammation of the sacroiliac joint (red arrow), and in a different patient, the MRI shows a slipped epiphysis (yellow arrow).

Arthrography The usefulness of this procedure is limited, as it is invasive and requires sedation or anesthesia. Arthrography is appropriate to confirm joint penetration in negative taps for suspected joint sepsis and for special situations in managing DDH. The role in LCP disease is more controversial.

Magnetic resonance imaging (MRI) These studies are the most expensive and require sedation for infants and young children. MRI studies are most useful in assessing intraarticular disorders of the hip. Cartilagenous loose bodies or fracture fragments, deformity of the cartilagenous femoral head, status of the growth plate, and avascular necrosis are usually definable.

Computerized tomography (CT) Order CT studies to evaluate inflammatory conditions such as an iliopsoas abscess or the configuration of the upper femur and acetabulum. CT scans have replaced to––mog–––raphy in assessing AVN and physeal bridges.

Three-dimensional CT reconstructions are often helpful in visualizing complex deformities of the hip, which is necessary when planning surgery (Fig. 21).

Figure 21. Three-dimensional CT reconstructions Reconstructions are useful in assessing complex hip deformity prior to surgery. The deformity of the proximal femur (red arrow) is secondary to avascular necrosis associated with DDH management in infancy.

Developmental Hip Dysplasia

DDH is a generic term describing a spectrum of anatomic abnormalities of the hip that may be congenital or develop during infancy or childhood. The spectrum covers mild defects such as a shallow acetabulum to severe defects such as teratologic dislocations. Teratologic dislocations occur before birth and include severe deformity of both the acetabulum and proximal femur.

Incidence

DDH incidence depends on how much of the spectrum is included (Fig. 22). At birth, hip instability is noted in 0.5–1% of joints, but classic DDH occurs in about 0.1% of infants. The incidence of mild dysplasia contributing to adult degenerative arthritis is substantial. It is thought that half of the women who develop degenerative arthritis have preexisting acetabular dysplasia.

Figure 22. Spectrum of hip dysplasia Dislocated hips are usually diagnosed during infancy, but hip dysplasia may not become evident until adult life and then present as degenerative arthritis.

Etiology

DDH is considered to be inherited by a polygenic mode. DDH is more common in breech deliveries (Fig. 23), in children with joint laxity (Fig. 24), and in girls.

Figure 23. Breech association DDH is often associated with breech presentation.

Figure 24. DDH and joint laxity Children with DDH often show excessive joint laxity.

Pathology

The acetabulum is often shallow and maldirected. The proximal femur shows antetorsion and coxa valga. Structural interpositions between the displaced femoral head and acetabulum are common (Fig. 25). The iliopsoas tendon is insinuated between the femoral head and acetabulum, causing a depression in the joint capsule. This gives the capsule an hourglass configuration. The acetabular labrum is inverted into the joint, the ligamentum teres is enlarged, and the acetabulum may contain fat (pulvinar).

Figure 25. Structures blocking reduction in DDH These interpositions may block reduction of the hip.

Natural History

Residual acetabular dysplasia is common in DDH. This may occur even following an apparently good early reduction (Fig. 26).

Figure 26. Conceptual chart showing disability from DDH Pain, altered function, and cosmetic problems often result from persisting hip deformity due to DDH.

The disability from dysplasia is related to the degree of displacement (Fig. 27). Greater displacement causes more function disability. Pain is most common with severe subluxation or articulation in a false acetabulum (Fig. 28).

Figure 27. DDH with residual acetabular dysplasia Radiographs at birth, 3, 10, and 19 years (top to bottom) show persisting dysplasia.

Figure 28. Adult degenerative arthritis Note that arthritis is most severe in the subluxated (red arrow) hip as compared with the totally dislocated hips (yellow arrows).

Diagnosis

The early diagnosis of DDH is critical to a successful outcome. Acetabular development is abnormal if a hip is subluxated or dislocated. Delays in management result in residual abnormalities and eventual degenerative arthritis.

Neonatal examination Every newborn should be screened for signs of hip instability. The hip should be examined using both the Barlow and Ortolani techniques (Fig. 29, 30). Examine one hip at a time. The infant should be quiet and comfortable so the muscles about the hip are relaxed. Use no force. Test for instability in several positions.

Figure 29. Barlow's sign Hip instability is demonstrated by attempting to gently displace the hip out of the socket over the posterior acetabulum.

Figure 30. Ortolani's sign The thigh is first adducted and depressed to subluxate the hip. The thigh is then abducted. The hip reduces with a palpable “clunk.”

Changing manifestations of DDH The signs of DDH change with the infant's age (Fig. 31). For example, the incidence of hip instability declines rapidly, 50% within the first week. The classic findings of stiffness and shortening increase over the first few weeks of life. These signs become well established in the older infant (Fig. 32).

Figure 31. Changing signs of DDH With increasing age, signs change.

Figure 32. DDH in older infant Note the limited abduction (red arrow) and shortening (blue arrow) on the affected left side.

Repeated examinations The hip should be examined during each “well baby” examination. In the neonatal period, DDH is detected by different signs, based on the infant's age. In early infancy, instability is the most reliable sign. Later, limitation of abduction and shortening are common. Beware of bilateral dislocations, as they are more difficult to identify (Fig. 33). If hip abduction is less than about 60° on both sides, order an imaging study.

Figure 33. Bilateral DDH This girl has symmetrical bilateral dislocations. The hip symmetry makes early diagnosis more difficult. Note the typical lumbar lordosis (arrow) that occurs with high dislocations.

Mother's intuition Although not proven, a common clinical experience is the accuracy of the mother's sense that something is wrong. Take the mother's intuition seriously (Fig. 34).

Figure 34. Mother's intuition This mother had DDH as a child. She suspected that her son's hip was abnormal, but the primary care physician found nothing on examination. She insisted on a radiograph. This study demonstrated a dislocation (red arrow). This scenario is not uncommon.

Hip-at-risk factors The presence of several factors increase the risk of DDH (Fig. 35, 36). When risk factors are present, the infant should be examined repeatedly and the hip imaged by ultrasound or radiography.

Figure 35. Risk factors These factors increase the risk of DDH and signal the need for careful and repeated examinations and imaging studies.

Figure 36. DDH and torticollis This infant showed the typical features of muscular torticollis with a sternocleidomastoid tumor (red arrow). A radiograph of the pelvis demonstrated DDH.

Hip “clicks” and asymmetrical thigh folds Hip clicks are fine, short-duration, high-pitched sounds that are common and benign. These are to be differentiated from “clunks,” the sensation of the hip being displaced over the acetabular margin. Clicks and asymmetrical thigh folds are common in normal infants (Fig. 37).

Figure 37. Asymmetrical thigh folds These occur in up to 20% of normal infants.

Radiography Radiographs become progressively more diagnostic with increasing age. By 2–3 months of age, radiography is reliable and this is the optimum age for screening by this method. A single AP radiograph is adequate. Draw the reference lines and measure the acetabular index. Normally, the AI in early infancy falls below 30°, is questionable in the 30°–40° range, and abnormal if above 40°. Hip subluxation or dislocation may often be demonstrated by the metaphysis of the femur positioned lateral to the lateral acetabular marginal line (Fig. 38).

Figure 38. Assessing radiographs in early infancy Note that in the normal hip (green arrow) the femoral metaphysis lies medial to the acetabular line. In the subluxated hip (yellow arrow) and dislocated hip (red arrow) the metaphysis falls progressively more lateral.

Ultrasound imaging The effectiveness of ultrasound imaging depends upon the skill and experience of the examiner. A skillful ultrasound evaluation is an effective screening technique for DDH (Fig. 39). The major problem with this screening is in the interpretation of the findings. If the hip is unstable, imaging is unnecessary. Imaging is appropriate to evaluate a suspicious finding, when hip-at-risk factors are present, and to monitor the effectiveness of treatment.

Documentation Document your hip evaluation. The failure to diagnose DDH is a common cause of suits against physicians. If the diagnosis is delayed, a record showing that appropriate examinations of the hip were made provides the best defense. DDH may be missed by even the most skilled examiners. Failure to screen for DDH is not acceptable by current standards.

Figure 39. Graf grading of DDH by ultrasound Drawing shows how the hips can be graded by measurements based on the ultrasound evaluation. The grades shown are divided by Graf into four types. Each is subdivided into subtypes (not shown). Reference lines are drawn to show the iliac margin (green), and the joint inclination (red). The alpha angle (yellow arc) can be constructed to show severity. The ultrasound image shows a severe displacement (orange arrow) of the femoral head (tan circle) in an infant with DDH.

Management

The management of DDH is challenging. Delays in diagnosis or problems in management often lead to residual anatomic defects and subsequent degenerative arthritis. The objectives of management include early diagnosis, reduction of the dislocation, avoidance of avascular necrosis, and correction of residual dysplasia.

Birth to 6 Months

This is the ideal age for management (Fig. 40). Treat DDH in this age group first with an abduction orthosis such as the Pavlik harness.

Figure 40. DDH management flowchart, birth to 6 months

Pavlik harness This widely used orthosis allows motion in flexion and abduction. Be certain that it is fitted properly (Fig. 41), both initially and as applied by the parents.

Figure 41. Proper fit of Pavlik harness The harness should be carefully fitted. Make certain it is the proper size for the infant. The harness must be comfortable. Check the fit after the parent applies the harness to assess problems before the parent leaves the clinic.

Advise the family on ways of transporting the infant (Fig. 42, 43).

See the infant weekly in the brace.

Figure 42. DDH mobility These carriers are ideal, as they provide abduction, mobility, and comfort for the infant and parent.

Figure 43. DDH splints and car transportation These splints should fit into standard infant car seats.

Make certain the brace is being fitted properly (Fig. 44) and progress is being made. The hip should become progressively more stable.

Figure 44. Pitfalls in management Triple diaper management (orange arrow) is ineffective and gives a false sense that treatment has been initiated. Pavlic harness errors are common. Make certain that the straps are not too tight (red arrows), the calf strap is not too low (yellow arrow), and the infant is comfortable (white arrow).

If harness treatment is successful, continue full-time bracing for 6–8 weeks to allow the hip to become stable. Monitor with ultrasound imaging or by AP radiographs of the pelvis about every 2–4 weeks. Continue the brace at night until the radiographs are normal.

If a dislocated hip has not reduced by 3–4 weeks, abandon Pavlic treatment. Persisting with this treatment may cause head deformity and posterior fixation, making closed reduction difficult or impossible. Proceed with closed or open reduction. Manage as is described for infants over 6 months of age.

Night splinting After the hip is reduced and stable, continue with night splinting to facilitate acetabular development. Continue until the radiographs are normal. A simple abduction splint is inexpensive and is well accepted by the infant.

Closed Reduction of DDH

Closed reduction is appropriate management for most infants under about 18 months of age with DDH. Management involves several steps.

Arthrographic Evaluation

This step can be omitted if the hip easily reduces, is stable, and the conventional radiograph shows satisfactory reduction. If reduction or pathology is uncertain, perform an arthrogram. Fill a 20-cc syringe with diluted dye (Fig. 45).

Figure 45. Figure. No caption available

Attach flexible tubing and fill the tubing with dye. Advance a 3-inch #20 needle through the adductor approach under fluoroscopic guidance into the empty acetabulum (Fig. 46).

Figure 46. Figure. No caption available

This step is facilitated by filling a second syringe with saline to be used to confirm joint entry. Once the joint is thought to be entered with the needle, inject a few cc of saline. Remove the syringe and medially rotate the leg. Joint entry is confirmed if saline drips from the needle hub. Repeat if necessary. Once entry is confirmed, attach the tubing and inject a few cc of dye while imaging the joint. Avoid excessive dye injection. Image in the position of dislocation (Fig. 47) and reduction (Fig. 48). Note any obstacles to reduction. The labrum (red arrow) is interposed but the medial dye pool (yellow arrow) is not excessive. Unless the hip is stiff, an interposed limbus often is accepted because the limbus will remodel with time. splinting.

Figure 47. No caption available

Figure 48. No caption available

Stability of Reduction

The second step is to determine the stability of reduction. Reduce the hip in flexion and determine the stability of reduction (Fig. 49).

Figure 49.

 If an adductor contracture limits abduction, narrowing the arc of stability (green or safe zone), perform a percutaneous adductor tenotomy (Fig. 50).

Figure 50. No caption available

Percutaneous Adductor Tenotomy

This procedure is performed with a pointed blade through a stab incision just distal to the inguinal crease. Identify the palpable tendon of the adductor longus and divide the tendon by placing the blade first on the lateral side of the tendon and cutting in a medial direction away from the femoral artery (Fig. 51).

Figure 51. No caption available

Indications for an Open Reduction

If the limbus is interposed but the hip is stable, allow the interposition to be resolved by remodeling. If the interposition results in an unstable reduction or if the dislocation cannot be reduced or cannot be maintained without excessive abduction, perform an open reduction.

Immobilize in a Spica Cast

Most reductions may be safely maintained with the hip positioned in about 80° of flexion, 45° of abduction, and neutral rotation. While maintaining this position, place the infant on a spica frame and apply first the liner and padding (Fig. 52) and then the cast. Be aware of the natural tendency for the person holding the position to allow the thighs to fall in greater abduction and less flexion during the cast application, making the reduction less stable and increasing the risk of AVN.

Figure 52. No caption available

Post-Reduction Management

Document the reduction by an AP radiograph in the cast. If the quality of reduction is uncertain, confirm the reduction by a CT scan prior to discharge. Plan to change the cast under anesthesia in 4–6 weeks. If limbus interposition was present, repeat the arthrogram during the second cast change to confirm that the reduction remains concentric. Remove the second cast in the clinic. Follow with shielded AP pelvic radiographs at 3, 6, 12, 18, 24, 36, and 48 months following cast removal. Some advocate night splinting until age 3 years, but no data confirm the value of this

Medial Approach Open Reduction (Ludloff)

This procedure was described by Ludloff in 1908 to provide a direct approach for open reduction of the hip in DDH. This procedure is one of several approaches for open reduction (Fig. 53).

Figure 53. No caption available.

Indications

The procedure is useful for management of dislocations of the hip due to DDH and arthrogryposis in infants under about 18 months of age.

Technique

Preparation Place a folded towel to elevate the pelvis (Fig. 54). If necessary both hips may be reduced at one operative setting. Perform an arthrogram if indicated (Fig. 55). Prepare the skin, and drape with the limb(s) free (Fig. 56). Abduct the hip and identify the adductor longus tendon.

Figure 54. No caption available.

Figure 55. No caption available.

Figure 56. No caption available.

Approach Make a 3-cm skin incision 1 cm distal and parallel to the inguinal crease centered over the anterolateral margin of the adductor longus tendon. On the lateral aspect of the incision, identify and avoid the long saphenous vein. Identify the interval just lateral to the adductor longus muscle and tendon. Through this interval, identify the lesser trochanter. This is best done by palpation (Fig. 57). Bring the trochanter into profile by flexing and laterally rotating the thigh. Extend the finger dissection until the prominence of the trochanter is palpated. Place retractors to visualize the trochanter and free overlying soft tissue (Fig. 58)

Figure 57. No caption available.

Figure 58. No caption available.

Psoas tenotomy Place a curve clamp around the psoas tendon just above its insertion (Fig. 59). Divide the tendon completely (Fig. 60). Free the hip capsule. Apply traction to approximate the femoral head within the capsule and rotate the thigh to feel the rotation of the femoral head.

Figure 59. No caption available.

Figure 60. No caption available.

Reduction Incise the capsule and extend the capsulotomy medially to include the transverse acetabular ligament. Perform a tendinotomy of the adductor longus tendon. Remove the ligamentum teres and pulvinar to allow a concentric reduction. To confirm that division of the ligament is complete, slide a curved clamp over the medial acetabular margin. Reduce the dislocation (Fig. 61).

Figure 61. No caption available.

Stability Determine the arc of stability and the degree of flexion, abduction, and rotation that provides optimum stability while remaining within the safe zone. Obtain an AP radiograph with the hip reduced. The surgeon should maintain this position of stable reduction while an assistant performs the subcutaneous skin closure and applies the spica cast (Fig. 62). To ensure maintenance of the reduction, make a second comparable AP radiograph in the cast. If any loss of reduction is demonstrated, remove the cast, re-reduce the hip, and apply a new cast.

Figure 62. No caption available.

Postoperative Care

Confirm the reduction with a CT scan. Expect considerable swelling about the perinenum. The patient may be discharged the next day. Reschedule for cast change in 6 weeks. Continue cast immobilization for 12 weeks. Maintain afterwards in a night splint (Fig. 63). About a third of the hips show persisting dysplasia and require a pelvic osteotomy.

Figure 63. No caption available.

Complications

Redislocation is best prevented by thorough release and careful positioning and follow-up in the cast. Avascular necrosis is the most common complication, as with other methods of reduction. Try to avoid by careful dissection for exposure and positioning in the cast without excessive abduction.

6 to 18 Months

In this age group, most cases of DDH can be managed by closed reduction and spica cast immobilization (Fig. 64, 65).

Figure 64. Home traction Setup at home is less expensive, less stressful for the infant, and often more convenient for the family.

Figure 65. Spica cast immobilization Infants require cast immobilization to retain the reduction of a dislocated hip.

Traction The need for traction is controversial. The current practice is to omit traction in most cases. Traction may be useful if the hip is stiff and closed treatment is planned. Use home traction when possible. Maintain for about 3 weeks with the legs flexed and abducted about 45° with 2–3 pounds of traction applied to each limb (Fig. 66).

Figure 66. DDH management flowchart, 6 to 18 months

Scheduling Schedule and obtain consent for a closed, or possibly open, reduction.

Reduction by closed means is first tried. If unsuccessful, open reduction is required. These procedures are outlined on the previous page.

Arthrography is useful when the quality of reduction is uncertain or the decision regarding management is difficult [D].

Follow-up After reduction, the infant should be followed carefully to assess the effect of time on growth, reduction, and acetabular development. Follow with AP radiographs made quarterly through infancy, yearly though early childhood, and then about every third year during middle and late childhood. The frequency of follow-up studies should be individualized based on the severity of any residual dysplasia.

18 to 30 Months

In this age group, operative management is usually required (Fig. 67). Occasionally, an infant with a “loose dislocation” can be managed as described in the flowchart for infants 6–18 months of age. If the hip is unusually stiff, be prepared to add femoral shortening, as described for management of children over 30 months of age.

Figure 67. DDH management flowchart, 18 to 30 months

Management Manage with an open reduction through an anterolateral approach and perform a concurrent Salter or Pemberton osteotomy. The open reduction is technically challenging. Add the pelvic osteotomy to improve results and save the child a second procedure.

Open reduction is the most difficult part of the procedure. The pelvic osteotomies are relatively simple, but the reduction can sometimes be difficult. The open reduction requires good exposure, careful dissection to minimize the risk of avascular necrosis, and a concentric reduction. The obstacles to reduction must be corrected (Fig. 68).

Figure 68. Open reduction Open reduction is often difficult, and obstruction must be corrected.

Iliopsoas tendon This tendon is interposed between the femoral head and acetabulum and must be released.

Capsular constriction Open the capsule widely to ensure a complete release.

Transverse acetabular ligament This structure lies across the base of the acetabulum and will block a deep concentric reduction unless released.

Pulvinar is fatty fibrous tissue that often fills the depth of the acetabulum. Remove with a rongeur.

Ligamentum teres is elongated and sometimes hypertrophied. Removal is usually required. The vascular contribution through this ligament is minimal.

Limbus is often inverted and hypertrophied. Do not excise this structure. Once the hip is concentrically reduced, the limbus will remodel and form the labrum, an important structure for hip stability and longevity.

Concurrent osteotomy This choice may be based on the pathology and on the experience and preference of the surgeon.

Femoral osteotomy Proximal femoral varus osteotomy is becoming less commonly used because the acetabular dysplasia is the more significant deformity. Include only minimal rotational correction.

Salter innominate osteotomy is suitable for unilateral mild to moderate dysplasia. The procedure is simple, risks are few, and results good.

Pemberton pericapsular osteotomy (Fig. 69) is more versatile because it can be performed bilaterally, does not destabilize the pelvis, provides greater correction, and requires no internal fixation. Avoid overcorrection. Stiffness is more common with this procedure, as the operation changes the shape of the acetabulum.

Figure 69. Pemberton pericapsular osteotomy The osteotomy hinges at the triradiate cartilage (red arrow) and graft wedges open the osteotomy (yellow arrows).

Postoperative care is determined by the treatment. If closed or open reduction is performed with an osteotomy, plan at least 12 weeks of spica cast immobilization. Usually, the cast is changed once or twice during this period. If a concurrent osteotomy is performed, stability is improved and only 6 weeks of immobilization are necessary.

Follow-up must be continued until the end of growth. Usually, a single AP radiograph of the pelvis is made every 6 months for 3 years, then yearly for 3 years, then every 3 years until maturity. At each visit, compare the current study with previous radiographs to determine the effect of time and growth on the development of the hip.

30+ Months

In this older age group, the opportunity to achieve an early reduction has passed (Fig. 70). Avascular necrosis is still a threat and dysplasia is a certainty. Management is much more difficult and controversial, and a poor outcome with degenerative arthritis in early adult life is likely.

Indications for reduction Consider the child's age, bilaterality, the family's values, and the experience of the surgeon (Fig. 70).

Figure 70. DDH management flowchart, 30+ months Outcomes are seldom good or excellent in this age range

Early childhood In early childhood, reduction is usually appropriate. This requires a femoral shortening, open reduction, and a pelvic osteotomy (Fig. 71). If the dislocations are bilateral, correct one side at a time. Allow 6 months between procedures to allow the child to recover. Reduction improves function, reduces the limp, and may make performing some salvage procedure more effective.

Figure 71. Unilateral open reduction and pelvic and femoral osteotomy This combination of procedures is necessary in the child. Femoral shortening (red arrow) must be added to allow tension-free reduction. The distal fragment is aligned (black arrow) and fixed (green arrow).

Mid or late childhood In the older child, leaving the hip unreduced is a reasonable option, especially when the condition is bilateral (Fig. 72). The child will limp but is less likely to have pain. Hip arthroplasty may be elected after maturity.

Figure72. Bilateral DDH in the child Staged corrections can be done in early childhood. In late childhood or adolescence, leaving the hips unreduced may be prudent.

Pelvic ostoeotomy Select the type of osteotomy based on the severity of the dysplasia and the age at the time of treatment. Select the Salter osteotomy for mild dysplasia. This procedure can be performed at any age and it does not change the shape of the acetabulum. Select the Pemberton osteotomy if dysplasia is moderate or severe. Avoid this osteotomy if the child is older than 6 years of age or if the acetabulum is hypoplastic.

Femoral osteotomy Femoral shortening osteotomy is nearly always necessary. If the deformity is severe, the femoral shortening is performed first, then the open reduction, followed by the pelvic osteotomy. The femoral fragments are then aligned, with gentle traction on the limb. The overlap is then determined and the overlapping distal femoral segment is resected. The procedure is primarily a shortening osteotomy with little or no varus or rotational components required (Fig. 73).

Figure 73. DDH Management Avoiding avascular necrosis is often not appreciated as one of the primary objectives.

Avascular Necrosis

Next to achieving a concentric reduction, preventing AVN is of utmost importance. Unless the necrosis is mild, this complication causes altered proximal femoral growth, creates deformity (Fig. 74), and often leads to premature degenerative arthritis.

Figure 74. Type 4 deformity Note the progressive changes throughout infancy and childhood from a central physeal bridge (red arrow) with shortening of the femoral neck and relative trochanteric overgrowth.

Types The spectrum of AVN includes severe necrosis, extensive physeal bridge formation (Fig. 75), and shortening of the femoral neck, which leads to degenerative arthritis during adult life. At the other end of the spectrum is the mild resolving form characterized by irregular ossification but without physeal bridge formation and subsequent deformity.

Figure 75. Classification of AVN patterns These patterns depend upon the severity and location of the ischemic necrosis. Based on Kalamchi and MacEwen (1980) classification.

Type 1 This pattern is common and usually resolves spontaneously with no residual deformity.

Type 2 This type of bridge is common and may not be apparent in early childhood, becoming obvious toward the end of growth. These bridges cause a tethering of growth and, if eccentric, a tilting of the growth plate (Fig. 76).

Figure 76. Type 2 AVN Note the lateral bridge (arrow) with shortening of the superior portion of the femoral neck and tilting of the physis.

Type 3 This type of bridge is relatively uncommon and produces some shortening of the inferior aspect of the femoral neck and a more vertical orientation of the physis.

Type 4 Central bridges cause total arrest with shortening of the femoral neck, relative trochanteric overgrowth, and mild femoral shortening.

Management Manage the deformity based on its severity and the type of deformity (Fig. 77).

Figure 77. Management of AVN occurring as a complication of DDH treatment

Prevention Attempt to prevent AVN by using preliminary traction and open reduction in stiff hips with an obstructing limbus, percutaneous adductor tenotomy, femoral shortening in the child, and immobilization in the “safe” or human position. Despite all precautions, AVN may still occur (Fig. 78).

Figure 78. Reduction pitfalls Consider these factors. Some are controversial.

Early signs The early signs of AVN (Fig. 79) are often followed by evidence of a growth disturbance.

Figure 79. Early signs of AVN These are signs that suggest AVN. From Salter.

Deformity The type and severity of the deformity is related to the location and extent of the physeal bridge. The residual deformities of Type 4 AVN often require a combined distal and lateral transfer of the trochanter and a contralateral arrest of the distal femoral epiphysis. These procedures may be combined with the procedures performed at the age calculated to be appropriate for the epiphysiodesis to correct the leg length difference.

Persisting dysplasia

The third objective in DDH management is the correction of persisting hip dysplasia (Fig. 80). Dysplasia should be corrected during growth to prevent osteoarthritis.

Figure 80. Effect of growth on acetabular development Follow acetabular development by placing radiographs in chronologic order and assessing the effect of time. Measure the acetabular index (AI) for each study. Compare this sequence of measurements with the chart of normal AI measurements. If improvement occurs (yellow arrow) and the values become normal (green dots), treatment is not required. If AI values remain elevated (red dots and arrow), then pelvic osteotomy will be necessary.

Dysplasia may involve the femur, the acetabulum, or both. The most pronounced deformity is in the acetabulum. The most severe dysplasia includes subluxation. Subluxation and dysplasia cause osteoarthritis, which may begin during the teen years. Disability occurs later with simple dysplasia.

Femoral Dysplasia The proximal femur is anteverted and the head may not be spherical due to the dislocation. The deformity may be due to ischemic necrosis.

Acetabular dysplasia is the most pronounced deformity and includes shallowness and anterolateral orientation of the socket.

Acetabulofemoral relationship The femoral head is subluxated if not concentric with the acetabulum. The head may also be lateralized following growth with the head subluxated. The acetabulum often becomes saucer shaped, causing instability.

The femoral head may be spherical or aspherical as a result of ischemic necrosis. The fit with the acetabulum may be congruous or incongruous. Asypherical incongruity is common because, over years of growth, the acetabulum assumes a shape to match that of the femoral head.

Timing of correction Correct hip dysplasia as soon as it is evident that the rate of correction is unsatisfactory, preferably before age 5 years (Fig. 81).

Figure 81. Management of acetabular dysplasia Manage based on age, severity, congruity, and lateralization.

Establish a time line of a series of AP radiographs [A] of the pelvis taken at 4–6 month intervals during infancy and early childhood. Measure the acetabular index, note the smoothness of the acetabular roof (sourcil), and observe the development of the medial acetabulum (tear drop). Assess by studying the sequence of films. Perform a pelvic osteotomy if the AI remains abnormal and the other features remain dysplasic after 2 to 3 years of observation. Avoid delaying an obvious need for correction (Fig. 82).

Figure 82. Severe acetabular dysplasia Attempt to correct acetabular dysplasia before it becomes this severe.

Principles of correction Proper correction of hip dyplasia in DDH follows these certain basic principles:

• Correct the primary or most severe deformity. This is usually the acetabular deformity.
• Correction should be adequate. If the deformity is severe, combine a pelvic and femoral osteotomy or perform a shelf operation.
• Avoid creating incongruity. Avoid the Pemberton procedure in the older child. Consider the shelf or Chiari procedure if aspherical congruity is present.
• Medialize the lateralized hip in the older child with a Chiari osteotomy.
• Articular cartilage is more durable than fibrocartilage as develops in the shelf and Chiari procedures.

Reconstructive procedures These are procedures that provide articular cartilage for load bearing. Select the appropriate procedure based on the site of deformity, age, severity, and congruity [C, previous page]. The choices are numerous (Fig. 83).

Figure 83. Options for osteotomies of the hip Procedure is shown in red. Orange lines show fibrocartilage articulations.

Femoral osteotomy Femoral shortening is essential in the older child with unreduced DDH. Remove just enough bone to allow reduction. Reduce the neck–shaft angle by about 20°. Limit rotational correction to about 20°. See next page for details.

Salter osteotomy This is the best choice for correcting mild deformities at any age (Fig. 84). The osteotomy will reduce the AI about 10°–15° and the CE angle by 10°.

Figure 84. Salter osteotomy This procedure is useful for mild to moderate dysplasia and may be performed at any age after about 18 months.

Pemberton osteotomy This is the best choice for bilateral or moderate to severe dysplasia (Fig. 85) in children under the age of 6 years.

Figure 85. Pemberton osteotomy This osteotomy extended into the triradiate cartilage and provided excellent correction (red arrow).

Dega osteotomy The osteotomy is more posterior in the ilium, providing posterior and lateral coverage most suitable for neurodysplasia correction.

Triple osteotomies Several types are available. They provide the best choice for correcting moderate dysplasia in adolescence when spherical congruity is present (Fig. 86). These procedures are technically challenging.

Figure 86. Pelvic osteotomies These procedures are useful in dysplasia in the adolescent patient. The triple innominate osteotomy (yellow arrow) and the Ganz osteotomy (orange arrow) are shown.

Ganz osteotomy This periacetabular osteotomy allows major correction appropriate just before or after skeletal maturity [C]. The procedure is technically challenging.

Sutherland procledure This procedure is a double innominate osteotomy seldom performed because correction is limited.

Salvage procedures These procedures create an articular surface of fibrocartilage that is more prone to degeneration with time.

Chiari osteotomy This is appropriate when the hip is lateralized and severely dysplasic. It may be used with aspherical congruity. Avoid excessive medialization. Coverage is by fibrocartilage.

Shelf procedure This procedure enlarges the acetabulum with fibrocartilage. It is versatile and may be considered for severe dysplasia without lateralization when aspherical congruity exists. This is the least risky of the major procedures.

Varus Femoral Osteotomy

Proximal femoral osteotomy is useful in cerebral palsy, DDH, Perthes disease, and other conditions causing hip instability. To enhance stability and early union, perform the osteotomy at the intertrochanteric level and consider medial displacement of the distal fragment.

Fixation Methods

Select the method of fixation based on the procedure, patient age, concurrent procedures, and available devices.

Altdorf hip clamp (Fig. 87) is suitable for infants and young children. It is usually used in DDH. The clamp may be fabricated by cutting a notch in a standard fixation plate.

Figure 87.

Crossed pins or absorbable pins or screws (Fig. 88, 89, 90) require spica cast immobilization to supplement this fixation. The osteotomy must be high with a broad cancellous surface to provide stability. Multiple devices are necessary. Metallic fixation may be left in place.

Figure 88.

Figure 89.

Figure 90.

Coventry hip screw (Fig. 91, 92) is suitable for children.

Figure 91.

Figure 92.

AO blade plate (Fig. 93, 94) fixation is widely used. This fixation is very stable. Plan to place the fixation below the trochanteric apophysis.

Figure 93.

Figure 94.

Length Following Osteotomy

The osteotomy technique affects femoral length. Creating varus reduces femoral length. Intentional shortening may be appropriate when reducing a dislocated hip; maintaining length is an objective in Perthes disease.

Closing wedge osteotomy is often indicated, as the shortening is minimal and a broad contact is created (Fig. 95).

Figure 95. No caption available.

Intentional shortening (Fig. 96) is indicated when reducing a high-riding dislocation.

Figure 96.

Opening wedge [G] design is useful when preserving length is desired, as in Perthes disease.

Combining Procedures

Creating varus to enhance hip stability is often combined with other procedures.

Varus + rotational osteotomy (VDRO) (Fig. 97) is common in cerebral palsy. Use guide pins to monitor the amount of rotation.

Figure 97.

Varus + greater trochanteric apophysiodesis (Fig. 98) is used in managing Perthes disease. The apophysiodesis may be achieved by placing a screw with a washer across the apophysis, or by curetting out the apophysis.

Figure 98.

Varus osteotomy + pelvic procedures (Fig. 99) is used to enhance stability. The bone from a closing wedge may be used in creating a shelf or to provide the opening wedge for the Salter or Pemberton procedures.

Figure 99.

Examples

Some notable examples of varus osteotomy procedures are shown.

Perthes disease Double-level osteotomy with apophysiodesis. Varus osteotomy fixed with AO screws.

Cerebral palsy sequence showing bilateral VDRO procedures combined with a limited periacetabular osteotomy on the right hip.

Slotted Acetabular Augmentation

This procedure is one of the many shelf operations. The shelf enlarges the acetabulum by grafting bone over the joint capsule. The joint capsule under the graft undergoes metaplasia to fibrocartilage. As the coverage is fibrocartilage, the shelf procedures are considered as salvage operations. Shelves are easily combined with other procedures. For example, if coverage or congruity is inadequate with a Chiari, Salter, or Pemberton procedure, consider adding shelf to improve coverage.

Indications

The procedure is indicated if the acetabular deficiency is severe or if nonspherical congruity is present. Other factors that make a shelf attractive include excessive scarring; bilateral augmentation, as both sides can be corrected in one operative session; the need for combined procedures; and to provide containment in Perthes disease.

Contraindications

When indicated, hyaline cartilage moving procedures such as the Salter or Pemberton osteotomy are preferred. Excessive laterization is best managed by the Chiari procedure (unless bilateral).

Operative Planning

From a standing radiography of the pelvis, measure the CE angle and draw in a CE angle of 40°. Measure the needed width of the augmentation. Compare the standing radiograph with another taken in abduction in internal rotation. A difference in reduction indicates that the hip is unstable and a cast will be necessary.

Technique

Anatomy Note that the reflected head of the rectus takes origin at the superior margin of the acetabulum (Fig. 100).

Figure 100.

Approach Place a towel under the pelvis to elevate the hip. Prep and drape the leg free. Through a bikini incision, expose the iliac crest. Identify the sartorius rectus interval. Incise the fascia over the sartorius and dissect through the interval to the hip joint without exposing the lateral femoral cutaneous nerve. Divide the apophysis or sharply divide the origin of the abductors from the iliac crest. Strip the abductor origin from the anterolateral side of the ilium to expose the hip capsule.

Elevate tendon Identify the tendon of the reflected head of the rectus. Divide it anteriorly, and sharply elevate it from the underlying joint capsule while preserving its posterior attachments (Fig. 101).

Figure 101.

Create a slot in the ilium just at the lateral acetabular margin about 1 cm deep and 5 mm wide (Fig. 102). Extend it as far anterior and posterior as needed to provide required coverage.

Figure 102.

Graft Harvest abundant graft from the ilium (Fig. 103).

Figure 103.

Place graft Place cancellous graft into the slot and over the capsule laterally as determined to create a CE angle of about 40° (Fig. 104).

Figure 104.

Secure graft Secure the graft by resuturing the reflected head over the graft (Fig. 105).

Figure 105.

 Reattach the abductors. Place the additional graft under the abductors to create a thick augmentation (Fig. 106 – G). The graft should be congruous with the acetabulum (Fig. 106 – H). Close the wound and apply a spica cast if the hip is unstable.

Figure 106.

Postoperative Management

If the hip is unstable, immobilize in a cast for about 6 weeks. Nonweight-bearing crutching is continued until the graft has consolidated—usually an additional 6 weeks. Full activity is allowed at 6 months.

Examples

Unilateral augmentation Note the thick augmentation (Fig. 107).

Figure 107.

Bilateral augmentation Bilateral procedures may be performed concurrently (Fig. 108).

Figure 108. No caption available.

Pemberton Osteotomy

This pericapsular osteotomy was described by Pemberton in 1965. It has become more widely used with time for correction of dysplasia due to developmental hip dysplasia and neuromuscular disorders.

Indications

This osteotomy is indicated for correcting persisting acetabular dysplasia in the child less than 6–7 years of age with DDH and about 10–12 years of age with neurodysplasia. The procedure changes the shape of the acetabulum, as the osteotomy hinges at the triradiate cartilage.

Pemberton and Salter osteotomies have similar indications. The advantages of the Pemberton procedure are the feasibility to perform bilateral procedures in one operative session, the lack of need for pin fixation, and a greater capacity for correction. The disadvantage is the alteration in the shape of the acetabulum, which requires the procedure to be performed early in childhood to allow sufficient time for remodeling to create congruity with the femoral head.

Preoperative Planning

Make available curve osteotomes. Special Pemberton osteotomes with a 90° curve are available for the final portion of the osteotomy but are not essential. Determine in advance the need for an open reduction by abduction internal rotation radiographs and/or a preliminary arthrogram.

Technique

Prep and drape the leg free with the pelvis slightly elevated. Make a bikini incision parallel to and slightly below the iliac crest (Fig. 109).

Figure109. No caption available.

Expose the inner and outer pelvis through a standard approach. Place a retractor in the sciatic notch. Perform a psoas release (Fig. 110 – B) and an open reduction if indicated. Perform a curved osteotomy that starts just above the insertion of the rectus and curves paralleling the acetabulum and into the triradiate cartilage just lateral to the sciatic notch (Fig. 110 – C drawing & radiograph). If uncertain about the osteotomy, monitor with imaging. From the ilium, remove a triangular wedge of bone with the base about 2–3 cm (Fig. 110 – D). Open the osteotomy with a lamina spreader and place the graft (Fig. 110 – E drawing & radiograph) in under compression. Create an acetabular index of about 10°, but avoid overcorrection. Trim graft. The graft should be solidly impacted in the osteotomy and secure without fixation (Fig. 110 – F drawing & radiograph). Close the wound and apply a spica cast with the hip in about 30° flexion, 30° abduction, and neutral rotation. Remove the cast in the clinic in 6 weeks. Hip stiffness may occur but will resolve spontaneously over a period of a few weeks or months.

Clinical Examples

Unilateral dysplasia A 12-month-old infant with DDH following closed reduction is shown (Fig. 110 – G). Persisting dysplasia was noted at 24 months. A Pemberton osteotomy was performed at 28 months.

Bilateral dysplasia A 30-month-old infant with DDH has persisting dysplasia corrected by concurrent bilateral Pemberton osteotomies (Fig. 110 – H).

Figure 110. No caption available.

Salter Osteotomy

This single innominate osteotomy is useful to correct mild to moderate acetabular dysplasia from ages 18 months into adult life. The procedure is widely used, and good to excellent outcomes are usually reported. Modifications include infrapelvic lengthening and performing the osteotomy with an osteotome, preserving the medial cortical periosteal attachments, enhancing stability, and eliminating the need for internal fixation.

Technique

Exposure Expose the hip through a bikini incision (Fig. 111) and an iliofemoral approach splitting the iliac apophysis. Perform an open reduction as necessary. By subperiosteal dissection, expose the inner and outer surfaces of the ilium to expose the sciatic notch. Place retractors in the notch to protect the sciatic nerve.

Figure 111.

Psoas tenotomy In most patients, an intramuscular lengthening of the psoas is performed before the osteotomy. Identify the tendon within the muscle and divide only the tendon, leaving the muscle intact (Fig. 112).

Figure 112.

Osteotomy Perform the innominate osteotomy with a Gigli saw (Fig. 113).

Figure 113.

 Passing the wire saw around the notch is the most difficult step in the procedure. This may be accomplished by using the special saw passer, by placing a curved clamp around the notch, or by simply bending the saw blade and guiding it around with a curved clamp. Once the saw is passed, position the retractors to protect the soft tissues, and perform the osteotomy. Make certain the osteotomy exits at the anterior inferior iliac spine.

Graft Place a towel clip in the anterior iliac spine to secure the graft. Remove a triangular graft that includes the anterior iliac spine using a bone cutter or osteotome. Reshape the graft into the desired triangular shape with the base about 2–3 cm in width (Fig. 114 – D).

Placing the graft Place a second towel clip through the ilium just above the acetabulum. Place the leg in a figure 4 position, and with pressure on the flexed knee and traction on the towel clip, open and slightly laterally displace the acetabular segment. This should open the osteotomy laterally while keeping the medial cortical margins approximated (Fig. 114 – E). Place the graft in the open defect.

Figure 114.

Fixation Secure the fixation with two or three pins that penetrate the graft and both iliac surfaces (Fig. 115). These pins may be smooth or threaded. Make certain the pins do not penetrate the hip joint and are long enough for firm purchase on the lower fragment. Cut off the pins, allowing about 5–10 mm protruding above the cortical margin. It is important to cut the pins at a length that is long enough to facilitate removal but not so long as to cause skin irritation.

Figure 115.

Closure is standard with a subcuticular skin closure. Immobilize in a spica cast for 6 weeks.

Differences Based on Disease

DDH Correct before age 4 years when possible. Immobilize in a spica cast for 6 weeks. In the older, cooperative child, with firm internal fixation, nonweight-bearing for 6 weeks is adequate. Make certain that the hip is concentrically reduced before performing the osteotomy.

Perthes disease When performed without a femoral osteotomy to decompress the joint, establish a good range of motion preoperatively and consider fixation with three larger pins to allow early mobilization following surgery.

Examples

This 18-month-old female has a right DDH (Fig. 116). Open reduction was performed, but acetabular dysplasia persisted (Fig. 117). At age 4 years, a Salter osteotomy was performed (Fig. 118). Good correction was seen on radiographs taken at 8 (Fig. 119) and 16 (Fig. 120) years. The scar was linear and not noticeable (Fig. 121).

Figure 116.

Figure 117.

Figure 118.

Figure119.

Figure 120.

Figure 121.