Ultrasonography in congenital dislocation of the hip. Simultaneous imaging of both hips from in front

We describe a new technique for examining the infant hip using ultrasound. Both hips are imaged simultaneously via an anterior approach. The examination can be done with the hip either extended or flexed and abducted. The method has three advantages: 1) since both hips are imaged simultaneously, lines can be drawn to assist in determining the relationship between the femoral head and the pelvis; 2) proximal, anteroposterior and lateral displacement of the femoral head can all be demonstrated; 3) the method is applicable to the infant in a harness or a plaster cast to demonstrate maintenance of reduction of a dislocated hip. The usual direction of dislocation of the femoral head was anterior and lateral. Proximal migration was also observed in cases with more severe dislocation. In flexion, the dislocated head of the femur often moved posterior to the acetabulum. Of 1276 hips, in 638 infants aged from three weeks to one year, 49 showed congenital dislocation. The accuracy of our anterior method of sonography in diagnosing congenital dislocation of the hip compared well with the method of Graf and with radiography.     

Types of persistent dysplasia in congenital dislocation of the hip.

This article reports five types of persistent bony dysplasia in patients with congenital dislocation of the hip (CDH), suggests the pathogeneses, and discusses the treatment options. We consider the five types to be (1) maldirected acetabulum, (2) capacious acetabulum, (3) false acetabulum, (4) lateralized acetabulum, and (5) femoral deformity. The maldirected acetabulum persists when the acetabulum continues to face forward and laterally. The capacious acetabulum arises from joint instability; capsular laxity permits the proximal femur to slide within the acetabulum. The false acetabulum results from an ectopic fibrocartilaginous cavity in the pelvis created by the subluxated or dislocated femoral head.44 The lateralized acetabulum occurs with ossification of the cotyloid cavity from longstanding lateral subluxation or dislocation or premature closure of the triradiate cartilage. Femoral deformities include valgus and anteversion of the femoral neck, capital femoral physeal growth arrest, discrepancy between the greater trochanter and the femoral head, and femoral head asphericity. After clinical and radiographic evaluation, we believe that an understanding of the pathogeneses and types of dysplasia will facilitate appropriate treatment programs. Treatments consist of acetabular redirection, acetabular reconstruction, femoral osteotomies, and salvage procedures.     

Diagnosis by ultrasound of congenital dislocation of the hip joint

Two hundred thirty-four hips of 117 babies from one day to 18 months of age were examined ultrasonographically for congenital dislocation of the hip joint. Ten hips in eight babies were dislocated or subluxated and there were 11 hip dysplasias in seven babies. In the normal hip, the adaptation between the acetabulum and the femoral head is well demonstrated, and there is no apparent interposition of the limbus between the acetabular roof and the cartilaginous head. In the dislocated hip, the protrusion of the acetabular rim is not so clear as that of the normal hip, and the limbus is seen to be interpositioned between the acetabular roof and the cartilaginous head. In severe cases, the acetabular rim is hidden under the shade of the femoral head. Ultrasonography is an effective method of determining the incidence of dislocation and of diagnosing hip subluxation as well as dysplasia and does not have the hazards of x-ray examination.     

Diagnosis and imaging studies of traumatic hip dislocations in the adult

Traumatic dislocation of the hip represents a major injury that is associated with significant morbidity. In particular, the risk of osteonecrosis of the femoral head is greatly affected by the time it takes to reduce the hip. Therefore, thorough understanding of the clinical and radiologic features is essential if this injury is to be recognized and treated promptly. Most patients present in severe distress after a high-energy injury such as a motor vehicle accident. Associated injuries, particularly of the knee, are common and the leg usually is held in a specific posture characteristic of the direction of dislocation. Plain anteroposterior radiographs of the pelvis will clearly show the dislocation in most patients but lateral views or a computed tomography scan may be required to confirm the diagnosis and to show the direction if the signs are subtle. Associated acetabular wall fractures and femoral head fractures also may be identified by computed tomography scans. After reduction, plain radiographs alone are not adequate to assess reduction; computed tomography is more sensitive in detecting osteochondral fragments and may reliably detect residual subluxation of 2 mm in any part of the joint. Magnetic resonance imaging is useful in detecting changes of osteonecrosis but rarely is indicated in the early treatment of this condition.     

三维CT重建对先天性髋关节脱位的临床价值

目的探讨三维CT重建在先天性髋关节脱位(CDH)的临床应用.方法本组CDH患儿22例,其中双髋脱位15例,单髋脱位7例,另有正常髋2例,共计患髋37个,正常对照髋11个.采用Picker公司PQ6000螺旋CT机,在独立工作站进行表面遮盖成像(SSD)、最大密度投影(MIP)、多平面重建(MPR)和相关数据测量.结果分别对股骨头颈、髋臼及头臼关系行三维直观显示,运用MPR技术测量了髋臼指数(AI)和股骨颈前倾角(FNA).结论三维CT可以直观、全面及分解地显示髋关节结构,对于股骨头、髋臼形态和头臼关系的显示具有常规X线和普通CT平扫所无法比拟的优越性,加之更加精确的测量,大大提高了术前诊断的科学性和手术的预见性,为手术方案的制定提供了新的客观依据.     

Intraneural sciatic nerve pressures relative to the position of the hip and knee: a human cadaveric study

OBJECTIVES: To determine the effects of ipsilateral hip and knee position on intraneural sciatic nerve pressures. DESIGN: Intraneural sciatic nerve pressures measured in intact, fresh cadaveric specimens relative to ipsilateral hip and knee positions. LOCATION: Medical school anatomy laboratory. SUBJECTS: Randomly acquired adult cadavers. INTERVENTION: Pressure transducer placed within the sciatic nerve distal to the femoral attachment of the gluteus maximus. Intraneural pressures measured with the hip placed in 0, 45, and 90 degrees of flexion while the knee was positioned in 90, 45, and 0 degrees of flexion. MAIN OUTCOME MEASUREMENTS: Tissue fluid pressures within the sciatic nerve relative to the position of the ipsilateral hip and knee. Tissue fluid pressure within the sciatic nerve exceeded previously defined critical thresholds for alteration of neural microcirculation and function. Although increased intraneural pressures were realized as the hip was positioned in greater flexion and the knee was extended, clinically relevant pressures were realized only when the hip was flexed to 90 degrees and the knee was fully extended. Pressures with the limbs in these positions were fifty-five millimeters of mercury (range 38 to 74 millimeters of mercury). RESULTS: With the hip held flexed to 90 degrees, statistically significantly increased intraneural pressures were measured as the knee was extended from 90 to 45 degrees of flexion (p = 0.048) and again from 45 to 0 degrees of flexion (p < or = 0.01). With the knee positioned in 45 degrees of flexion, statistically significantly increased intraneural pressures were measured as the hip was flexed from 45 to 90 degrees (p < or = 0.0062). When the knee was held fully extended, statistically significantly increased intraneural pressures were measured as the hip was flexed from 0 to 45 degrees of flexion (p = 0.0006) and again when the hip was brought from 45 to 90 degrees of flexion (p < or = 0.01). CONCLUSIONS: Intraneural sciatic nerve pressures are influenced by the position of the ipsilateral hip and knee. The magnitude of the pressure elevation appears to be related to the excursion of the nerve as the linear distance between the greater sciatic notch and the distal aspect of the leg increases. Intraneural tissue fluid pressures measured within a localized section of the sciatic nerve appeared to exceed published critical thresholds for alterations of blood flow and neural function only when the hip was flexed to 90 degrees and the knee was fully extended.     

The natural history of congenital disease of the hip.

Fifty-four adults with eighty hips affected by congenital disease which had not been treated have been reviewed. Fifty-nine per cent of forty-two dislocated hips had fair or poor grading scores. The incidence of osteoarthritis was markedly increased in the presence of a well-developed false acetabulum. Unilateral dislocation led to valgus deformity and degenerative changes in the ipsilateral knee in seven of twenty-two patients. Dislocation did not increase the incidence of symptomatic lumbar spondylosis. The height of the dislocated head on the ilium was not found to be related to the prognosis for the hip, the knee or the lumbar spine and did not correlate with the development of the false acetabulum. Frank congenital subluxation eventually led to osteoarthritis of the hip.     

Magnetic resonance imaging after reduction for congenital dislocation of the hip

BACKGROUND: Reliable concentric reduction of the femoral head and subsequent retention in a centred position are indispensable preconditions for the remodelling of the acetabulum in developmental dysplasia of the hip (DDH) and to prevent damage to the hip joint, i.e. avascular necrosis. The objective of this study is to evaluate the necessity of verifying the reduced position of the articulation in the plaster cast. METHOD: MRI was carried out in 15 infants with 21 unstable hip joints after reduction under arthrographic control and fixation in a plaster cast in the 'human' position with the hips flexed above 90 degrees and abducted to 50 degrees or 60 degrees. When the reduction was found to be inadequate-the hip still partially or completely dislocated-the plaster cast was removed, reduction repeated, a new cast applied, and MRI carried out again. RESULTS: After primary reduction, 1 of 21 hips was dislocated, and 2 showed unsatisfactory reduction. Three hip joints out of 21 (14.3%) were not fixed in the plaster cast in the optimal centred position. CONCLUSION: In view of the number of inadequate reductions in plaster casts, we recommend verifying the position of the hip joint by MRI. This MRI documentation should be established as a standard examination post-reduction.     

Septic arthritis of the hip in the infant and young child

Septic arthritis of the hip is an orthopaedic emergency which, treated late or inadequately, can have devastating consequences for the developing hip joint. The invading organism, most commonly Staphylococcus aureus, usually spreads from either an adjacent area of osteomyelitis or by haematogenous seeding. The hip is typically held abducted, flexed and externally rotated. The child may be limping, with a pyrexia and raised erythrocyte sedimentation rate. If the diagnosis is doubtful, urgent ultrasound and aspiration can be helpful. The mainstay of treatment remains arthrotomy and antibiotic administration. The majority of children over 2 years recover well, but there is a poorer prognosis in infants and with a delay in treatment. Infants may need later reconstruction, which is aimed at maintaining a stable hip with the head centrally located in the developing acetabulum. If the head and neck are destroyed, trochanteric arthroplasty may produce more favourable results than leaving the hip dislocated.     

Proximity of the Femoral Neurovascular Bundle During Hip Resurfacing

A standard posterior approach was performed in 5 fresh frozen cadaveric limbs. An anterior incision was then used to measure the distance of the femoral neurovascular structures to the anterior capsule. Magnetic resonance imaging (MRI) of 11 hips was also analyzed to validate our cadaveric method. Cadaveric results demonstrated that before dislocation the femoral artery and vein were closest to the anterior capsule (mean distance, 21 mm), and the femoral nerve was the furthest away (mean distance, 25 mm). These results were not significantly different from the MRI findings. When the hip was dislocated, these distances significantly increased. This study suggests that the neurovascular structures are relatively well protected during an anterior capsulotomy performed during hip resurfacing. The procedure may be safer if the capsulotomy is performed with the hip dislocated and in a flexed position while cutting the anterosuperior aspect and in an extended position while cutting the anteroinferior aspect.     

A reappraisal of the Ortolani examination in children with developmental dysplasia of the hip

The Ortolani maneuver is currently accepted as an accurate test to detect developmental dislocation of the hip. However, the clinical sign does not always correlate with the findings seen on ultrasound. The ultrasound-documented position of the femoral head was correlated with the result of the clinical Ortolani examination to better understand the value and validity of the Ortolani test. Two populations were compared: hips with a positive Ortolani sign and hips with a negative Ortolani sign but with an ultrasound-documented dislocated hip. In the Ortolani-positive group, there were 45 patients (53 affected hips), and in the Ortolani-negative group, there were 24 patients (25 dislocated hips). Position of the femoral head at rest, side of involvement, and sex showed no significant difference between the Ortolani-positive and -negative groups. Mean age of patients in the Ortolani-positive group was less (mean, 28 days) and was statistically different (P < 0.05) from those in the Ortolani-negative group (mean, 91 days). In conclusion, dislocated hips that show similar femoral head movement can produce an Ortolani-positive examination in a younger patient and an Ortolani-negative examination in an older patient. The classic clinical method described by Ortolani for detecting hip dislocation in which the thigh of the affected hip is abducted and the femoral head was thought to be reducing into the acetabulum can be erroneous. All Ortolani-positive hips were abnormal, as the sensation characteristic of a positive Ortolani examination may be felt without full reduction and, in some cases, with no reduction, as documented by ultrasound.     

The effect of femoral component head size on posterior dislocation of the artificial hip joint

BACKGROUND: Posterior dislocation continues to be a relatively common complication following total hip arthroplasty. In addition to technical and patient-associated factors, prosthetic features have also been shown to influence stability of the artificial hip joint. In this study, a dynamic model of the artificial hip joint was used to examine the influence of the size of the head of the femoral component on the range of motion prior to impingement and posterior dislocation following total hip replacement. METHODS: Six fresh cadaveric specimens were dissected, and an uncemented total hip prosthesis was implanted in each. Each specimen was mounted in a mechanical testing machine and loaded with use of a system of seven cables attached to the femur and pelvis that simulated the action of the major muscle groups crossing the hip joint. The hip was taken through a range of motion similar to that experienced when rising from a seated position. The three-dimensional position of the femur at the points of impingement and dislocation was recorded electronically. The range of joint motion was tested with prosthetic femoral heads of four different diameters (twenty-two, twenty-six, twenty-eight, and thirty-two millimeters). RESULTS: Significant associations were noted between the femoral head size and the degree of flexion at dislocation in ten (p = 0.001), twenty (p < 0.001), and thirty (p = 0.003) degrees of adduction. Increasing the femoral head size from twenty-two to twenty-eight millimeters increased the range of flexion by an average of 5.6 degrees prior to impingement and by an average of 7.6 degrees prior to posterior dislocation; however, increasing the head size from twenty-eight to thirty-two millimeters did not lead to more significant improvement in the range of joint motion. The site of impingement prior to dislocation varied with the size of the femoral head. With a twenty-two-millimeter head, impingement occurred between the neck of the femoral prosthesis and the acetabular liner, whereas with a thirty-two-millimeter head, impingement most frequently occurred between the osseous femur and the pelvis. CONCLUSIONS: With the particular prosthesis that was tested, increasing the diameter of the femoral head component increased the range of motion prior to impingement and dislocation, decreased the prevalence of prosthetic impingement, and increased the prevalence of osseous impingement. CLINICAL RELEVANCE: These results suggest that femoral heads with a twenty-eight-millimeter diameter increase the range of motion after total hip replacement. This may be beneficial when additional factors compromising joint stability are encountered.     

Sonography in congenital dislocation of the hip

A new technique for ultrasonic examination of the hip joint was evaluated in neonatals and infants. An anterior approach was used with the sound sector centered over the femoral head and parallel to the femoral neck. The ultrasonograms corresponded to lateral radiographs of the joint with the leg in Lorenz' first position. It was possible to evaluate the size and depth of the acetabulum and the size and position of the femoral head. The projection also permitted a dynamic examination for determination of hip instability. Thus, the technique provided a method for an objective diagnosis in congenital dislocation of the hip (CDH). In 216 hips, the results of clinical evaluation for CDH were correlated with the degree of instability demonstrated by ultrasound. The comparison showed the clinical diagnosis to be highly inaccurate.     

Femoral neck fracture complicating orthopedic reposition of a dislocated hip: four cases

Posterior dislocation of the femoral head with fracture is an exceptional hip injury. Emergency reduction is required. Reposition into the acetabular cavity of the dislocated femoral head may not be feasible. Irreducibility, instability, and more rarely accidental fracture of the femoral neck may also occur. We encountered this latter complication in four patients and report here its frequency and mechanism and propose preventive therapeutic measures. Seventy dislocations and fracture-dislocations of the hip were treated in our unit from March 1997 to February 2003. Among these cases, fourteen hip dislocations were complicated by femoral head fractures. Fracture of the femoral neck occurred during reduction in four. All four cases occurred in men, mean age 49.7 years, who were traffic accident victims (drivers or passengers). There were two Pipkin IV fracture-dislocations and two Pipkin II. The first reduction, achieved under general anesthesia in an emergency setting, was performed by an orthopedic surgeon in one patient and a general surgeon in three patients. Arthroplasty was used to treat the femoral neck fracture in three patients and pinning in one. We reviewed retrospectively the clinical and imaging data before and after reduction. Sub-capital fracture situated 4.0 cm (mean, range 3.5-4.5 cm) from the lesser trochanter occurred in all four cases. The head remained attached above and posteriorly to the acetabulum and was rotated less than 90 degrees . The fragment remaining in the acetabulum was displaced in two cases. In one patient, the fracture-dislocation of the head was associated with a fracture of the posterior rim of the acetabulum. This complication appears to result from an abrupt inappropriate reduction movement. The neck fracture would occur when capsulomuscular retention of the femoral head is associated with a head defect which catches on the rim of the acetabulum during the reduction movement. Neck fracture during reduction of traumatic hip dislocation is a serious complication. Prevention of this iatrogenic event requires a slow, progressive reduction limiting the trauma to a minimum; first intention open surgery may be required in selected cases.     

Tectoplasty for painful dislocation or subluxation of the hip. Long-term evaluation of a new acetabuloplasty

Tectoplasty is a new acetabuloplasty which aims to provide an extra-articular weight-bearing surface in cases of dysplastic acetabulum, hip subluxation or dislocation with a false acetabulum. The lateral wall of the iliac bone at the lateral edge of the affected acetabulum is raised as a proximally-based flap and massive bone grafts are inserted to provide a congruous, non-absorbable roof for the capsule and femoral head. An advantage is that the weight-bearing surface can be formed away from the original acetabulum, wherever the dislocated or subluxated femoral head may lie. Of 34 hips with congenital dislocation or severe subluxation treated by this method, 27 were evaluated after an average follow-up of 12 years. At review the patients averaged 35 years of age and satisfactory results with good relief of pain had been obtained in 78%. The results were unsatisfactory when degenerative changes had already developed before operation. Tectoplasty is indicated for pain due to congenital subluxation or dislocation of the hip under the age of thirty, in the absence of advanced osteoarthritis.     

可吸收钉棒内固定治疗股骨头、髋臼骨折

目的 应用可吸收钉棒(SR-PLLA)内固定治疗10例股骨头骨折、髋臼骨折的疗效。方法 本组病例中,4例股骨头骨折,4例髋臼后缘骨折,两者合并存在2例,术前9例合并髋关节后脱位,1例合并骶骼关节开放性脱位。均经髋关节后外侧或后路切开复位可吸收螺钉及固定棒固定,术后持续骨牵引6周,并主动下肢屈髋活动。结果 随访平均14.5个月,按髋关节功能评定标准:优6例,良3例,可1例,术后一年发生股骨头缺血性坏死1例,无感染、骨折移位、关节僵硬等并发症发生。结论 SR-PLLA内固定是治疗股骨头骨折、髋臼骨折的理想方法。     

Posterior dislocation of the hip joint with fracture of both the femoral head and neck

Fracture of both the femoral head and neck associated with posterior hip dislocation is a rare injury. This report describes a rare case of fracture-dislocation of the hip joint with a separated femoral head with a residual fragment in the acetabulum, and a subcapital fracture. We performed open reduction with internal fixation immediately after the injury. Osteonecrosis of the femoral head was detected one year after the surgery, however this patient had no symptoms related to the hip joint.     

不同髋臼杯前倾位置和球头假体大小对全髋关节置换术后后方稳定性的影响

目的探讨髋臼杯的前倾位置与球头大小对全髋关节置换（THA）术后后方稳定性的影响。方法利用计算机导航技术在假骨上模拟THA术后,不同髋臼杯前倾位置和不同球头大小在屈髋90°、内收0°和内收30°时髋关节内旋到引起脱位的角度进行测量和比较发生后脱位时的角度差异。结果在髋臼杯外展45°、前倾0°、5°、10°、15°时,28mm和36mm球头在屈髋90°内收0°和30°睛况下内旋至脱位的角度有明显差别（均为P〈0．05）,36mm球头可有更大的内旋角度,稳定性优于28mm球头。但当髋臼杯前倾20°时28mm与36mm球头内旋至脱位的角度间的差异无统计学意义（P〉0．05）,内收30°时比内收0°时髋关节内旋至脱位的角度减小。关节稳定性随髋臼杯前倾减小而下降。髋臼杯前倾0°和髋关节内收30°时,28mm球头在外旋位时就可发生脱位。结论髋臼杯前倾角度增加可增加THA术后关节的稳定性,大球头的稳定性优于小球头,前倾达到某一角度时,大球头和小球头间的后方稳定性无差别。     

Traumatic anterior dislocation of the hip associated with ipsilateral femoral neck fracture: a case report

A thirty-nine-year-old female patient was brought to the emergency room following an automobile accident. Radiographic examination revealed a subcapital fracture of the left femur associated with anterior femoral head dislocation, and a contralateral comminuted femoral shaft fracture. Computed tomography showed that the acetabulum was empty, with the femoral head dislocated anteriorly close to the obturator foramen. Uncemented total hip arthroplasty and locked intramedullary nailing were performed on the left and right sides, respectively. Sixty-two months after surgery, she had no difficulty in performing daily activities.