Christopher P. Beauchamp
The list of miscellaneous disorders that can affect the hip is lengthy. This section addresses some of the unique and more troublesome problems. Patients can present with symptoms of pain and functional loss or may simply present with a radiographic abnormality discovered incidentally (Table 7-1). Some of these problems are rare and can be difficult to treat. Some disorders have characteristic radiographic features that can be diagnostic (Table 7-1).
Pigmented Villonodular Synovitis of the Hip
Pigmented villonodular synovitis (PVNS) of the hip is an uncommon disorder characterized by an effusion, thickened hyperplastic synovium with joint erosions and cysts. It can present with an insidious onset, and the ultimate diagnosis can be difficult to make as it may mimic other inflammatory disorders. Patients who present with a nontraumatic monoarticular effusion should be suspected of having PVNS.
Etiology
The cause is unknown. It is debatable whether this disorder is the result of a true neoplastic process or whether it is merely a reactive monoarticular arthritis. The fact that it is monoarticular supports the concept that it is a neoplastic disease. Although rare, polyarticular disease can occur.
Epidemiology
PVNS occurs equally in males and females and is most common in the third to fifth decade of life. The incidence of this disorder is 1.5 per million; it most commonly affects the knee, hip, ankle, hand, and foot.
Pathology
The gross appearance is characteristic: the joint fluid is blood tinged and the synovium is thickened, nodular, and stained reddish brown with yellow nodules. Histologically, there is a mononuclear stromal cell infiltrate with multinucleated giant cells and foamy histiocytes and there are areas of macrophages containing hemosiderin.
Presentation
Patients usually present with an irritable hip, with pain and diminished range of motion. Symptoms can be insidious.
Radiographic Examination
Plain radiographs range from being normal to end-stage arthritis. The classic radiographic changes that are present include bone erosions in the head and neck of the femur and the acetabulum. The MRI typically shows an effusion with hypertrophic synovium with areas of low signal on T1 and bright areas on T2. Because of the hemosiderin present, there will be other small areas of low signal intensity of T1- andT2-weighted images.
Diagnosis
The diagnosis is most often made with MR imaging. The differential diagnosis may include infection or other inflammatory arthritis and an aspiration may be appropriate. Histologic changes from other inflammatory arthritis disorders can often mimic PVNS, particularly if there have been recurrent hemarthroses; thus this condition is often overdiagnosed on pathology reports.
Treatment
The preferred treatment for PVNS is open synovectomy. Attempts at radionucleotide synovectomy have been disappointing. The surgical recurrence rate is high, especially with the diffuse form; therefore, thorough synovectomy, curettage of the cystic lesions, and bone grafting of cavitary defects must be meticulously performed. To visualize the joint completely, the hip must be dislocated. Surgical dislocation of the hip is safe, and the risk of avascular necrosis is very low if the procedure is done correctly. I prefer a
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classic trochanteric slide osteotomy. Care is taken to avoid dissection of any of the posterior capsular structures. The anterior hip capsule is exposed, and an arthrotomy is made in line with the femoral neck. Flaps are then created at the base of the neck toward the lesser trochanter anteriorly and posteriorly along the superior aspect of the capsule just distal to the labrum. A Z-shaped capsular arthrotomy now permits an anterior dislocation of the hip. The ligamentum teres is avulsed or transected, and the dislocation is complete. Adequate visualization now permits a complete synovectomy.
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TABLE 7-1 Radiographic Diagnoses any Orthopaedic Surgeon Should be able to Make |
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For recurrent disease or aggressive extensive initial disease, moderate dose radiation therapy can be considered. Older patients or those with associated substantial degenerative arthritis are best managed with complete synovectomy and an arthroplasty. Fortunately, with more choices in implant materials, such as metal on metal or ceramic on ceramic bearing surfaces, younger patients can enjoy the reduced recurrence rate and better function that total joint arthroplasty can offer.
Long-Term Outcome
The risk of local recurrence is significant. Patients need to be followed radiographically with periodic MRI scans. A baseline scan is done 6 weeks postsynovectomy. Asymptomatic small local recurrences can be observed. Patient counseling is very important with this disease, because there is risk of progressive arthritis and subsequent need for a total hip arthroplasty. At times this can be a frustrating, progressive, difficult-to-control disease, and patients need to understand this at the beginning of treatment.
Case Presentation
The patient is a 22-year-old man who presents with a one month history of increasing hip pain with episodes of severe hip pain. His physical examination reveals a limp and a painful restricted range of motion. His plain x-ray films and CT scan (Fig. 7-1A–C) demonstrate subtle soft tissue swelling and multiple radiolucent lesions affecting the femoral head and acetabulum. His MRI shows hypointensity on T1 and increased intensity on T2 with low T1 and T2 areas consistent with hemosiderin deposits (Fig. 7-1D–F). He was treated with an open arthrotomy with surgical dislocation of the hip, complete synovectomy, and curettage and bone grafting of the head and acetabular lesions (Fig. 7-1G). Nine months later he underwent removal of the screws in the event a total hip was ever required in the future. Currently 4 years later he remains in remission and has maintained a normal joint space (Fig. 7-1H).
Synovial Chondromatosis
This disease of unknown cause is characterized by a metaplastic transformation of synovial tissue. The disease can affect any synovial tissue. The synovium becomes thickened with the formation of nodules of cartilage. The cartilage nodules can grow and become fixed nodules or break off and become loose bodies. Bathed in synovial fluid, they can grow and ossify. The loose fragments can range from tiny radiolucent pieces of cartilage to large bony masses centimeters in diameter.
Epidemiology
The typical age group for this disorder is in the third to fifth decade. Males outnumber females four to one.
Presentation
Patients present usually with an insidious onset of pain, limp, and restricted range of motion. Symptoms of a loose body with locking and giving way are common. Occasionally patients present with end-stage osteoarthritis. The disease is monoarticular affecting the knee, shoulder, elbow, and hip most commonly. Extra-articular disease can occur anywhere there is synovial tissue.
Radiographic Examination
Plain radiographs can range from normal to end-stage osteoarthritis with numerous ossified loose bodies. However, the many loose bodies may be cartilage and unossified, and therefore not visible on plain radiographs. In the early stages, differentiation between other causes of an irritable hip can be difficult.
Computed tomography and magnetic imaging can often be diagnostic. These can demonstrate synovial proliferation with the presence of nodular disease and numerous loose bodies. Once calcified and ossified, the loose bodies can be more readily seen. Occasionally a large synovial extension into the soft tissues can result in an impressive collection of loose bodies.
Treatment
The preferred treatment is removal of all loose bodies and a complete synovectomy. This can be accomplished arthroscopically in some cases, but an open synovectomy allows a more thorough debridement. Arthroscopy has the
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advantage of lower morbidity with less subsequent scarring. Repeat arthroscopy also is more easily performed forrecurrent disease. If an adequate debridement and synovectomy cannot be performed with a scope, an open synovectomy with dislocation of the hip as described above should be performed. This disease has a high chance of local recurrence.
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Figure 7-1 A–C: Plain radiograph and CT scan demonstrating radiolucent lesions in both the femoral head and acetabulum with a normal joint space. D–F; MRI appearance, low signal on T1, bright on T2, marked proliferative synovitis, and small areas of dark signal on both T1 and T2 from hemosiderin. G–H: Immediate postoperative and 4-year follow-up films showing cavitary lesions following curettage and grafting. |
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Figure 7-2 A: Plain radiograph demonstrating numerous ossified loose bodies. B: CT scan showing marked synovial proliferation and ossified loose bodies C: MRI T2-weighted image revealing numerous nonossified, noncalcified cartilaginous loose bodies. D: Progression of chondromatosis to advanced secondary degenerative arthritis 4 years later. (Photos A, B, and D courtesy of John Hunter, MD.) |
Case Presentation
The patient is a 55-year-old man who presents with a 3-year history of increasing pain, a limp and diminished range of motion of his right hip. He has had numerous episodes of locking and giving way of his leg, but these events were short lived and are occurring less frequently
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now. His physical examination reveals a limp and a markedly reduced painful range of motion. His plain radiographs, CT, and MRI scan demonstrated minimal osteoarthritis with numerous ossified loose bodies (Fig.7-2A–C). The radiographic features are diagnostic of synovial chondromatosis. Four years later the patient developed progressive osteoarthritis. (Fig. 7-2D). Treatment at this stage consisted of a total hip arthroplasty with synovectomy and removal of the loose bodies.
Fibrous Dysplasia
Fibrous dysplasia is a benign developmental abnormality affecting bone. It can be solitary (monostotic) or multiple (polyostotic) and can have a wide variation in severity. It can sometimes be associated with other medical conditions. This developmental abnormality results in the failure of primitive bone remodeling. The immature bone is imbedded in dysplastic fibrous tissue and is poorly mineralized; it therefore contains the normal constituents of bone but in a very disorganized form, resulting in marked reduction in mechanical strength. The bone is therefore prone to slowly developing deformities and pathologic fractures.
Etiology
The cause of fibrous dysplasia is now believed to be a postfertilization somatic cell line gene mutation. The severity of the disease is dependent on when and where the mutation occurs during embryogenesis.
Epidemiology
Males and females are equally affected. The disease may present at any age and is nonhereditary. The most common sites of involvement are the long bones, pelvis, ribs, and craniofacial bones.
Clinical Features
Patients present with fibrous dysplasia as an incidental finding, pain, deformity, or fracture. The pain can be owing to the mechanical insufficiency caused by the abnormal tissue or the lesion itself. The degree of deformity depends on the severity and location of the bone involved. The proximal femur is a common location, and the mechanical weakness can result in severe angular deformities with limb-length inequality. This is especially so in polyostotic fibrous dysplasia as it tends to progress in adult life. The classic deformity of the proximal femur is the so-called “shepherd's crook” deformity, a pronounced varus deformity with bowing of the femur and shortening of the limb.
Radiologic Features
Most lesions are noted incidentally. The plain radiograph is usually diagnostic, and the x-ray film characteristics are so distinctive that a diagnosis can be made with confidence. The lesion is usually well demarcated and consists of fairly homogenous fibro-osseous calcified material that has a ground-glass appearance. Occasionally the plain radiographs can be nonspecific owing to cystic degeneration, multiple fractures, or deformity. Patients with a nonspecific radiographic appearance require further investigation and sometimes a biopsy.
Computed Tomography
Computed tomography gives a detailed high-resolution view of the bone, and a diagnosis can often be made at this point. If the radiographic appearance is atypical, an MRI study and a biopsy may be needed.
Magnetic Resonance Imaging
The magnetic resonance image is usually a low-signal T1-weighted image and a T2 signal of higher intensity. The signal intensity is determined by the relative composition of fibrous tissue and mineralized immature bone. There may also be areas of cystic degeneration with a high T2 signal.
Treatment
The role of surgery is not to “remove the tumor” as it is not a neoplastic condition but rather to deal with the mechanical consequences of a relatively weak and deformed bone. Treatment of the deformed bone is difficult because of its poor mechanical strength, and eradication of the fibrous dysplasia usually is not possible.
Case Presentation
The patient is a 20-year-old woman with a history of increasing activity-related pain affecting the right groin and thigh. She has mild pain at rest and moderate pain at night. Her physical examination is essentially normal. Her CT scan shows a lesion in the femoral neck, largely radiolucent with a deficiency in the medial aspect of the cortex (Fig. 7-3A). There is a well-defined reactive rim with increased bone density. The radiographic differential is large, favors a benign process, and includes nonossifying fibroma, fibrous dysplasia, unicameral bone cyst, and eosinophilic granuloma, and so on. Owing to her symptoms, the location of the lesion, and the cortical defect, the patient underwent an open biopsy via a transtrochanteric window under fluoroscopic guidance. Frozen section was consistent with fibrous dysplasia. The lesion was then curetted, and a fibular strut graft was passed up through the neck along the medial cortex of the neck (Fig. 7-3B). A cortical fibular allograft strut was selected for the reconstruction to reduce the risk of dysplastic bone remodeling of the graft. Her follow-up radiograph 4 years later demonstrated a healed graft without replacement by fibrous dysplasia (Fig. 7-3C).
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Figure 7-3 A: Coronal CT scan demonstrating relatively nonspecific lesion with a pronounced rim of reactive bone surrounding a radiolucent lesion with a defect in the femoral neck. B: Intraoperative image following biopsy and curettage of fibrous dysplasia with insertion of an allograft fibular strut. C: Four-year follow-up radiograph showing healing of the graft and no evidence of graft erosion by fibrous dysplasia. |
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Figure 7-4 A: Plain radiograph of previously treated fibrous dysplasias. Some areas of radiolucency with a ground glass appearance. Previous Rush rod and surgical changes. Note the varus deformity. B: Follow-up radiograph 2 years following corrective osteotomy and reconstruction nail fixation. |
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Case Presentation
A 46-year-old man presents with a long history of episodes of his right hip and thigh pain. He has had episodes of severe pain sometimes requiring crutches. As a child he underwent a surgical procedure because of recurrent pain. His physical examination revealed a 1.5-cm. limb-length discrepancy with shortening in the femur. He had a nearly full range of motion of his hip with minimal pain at the extremes. His radiographs demonstrate mild osteoarthritis, a varus deformity of the femoral neck and proximal femur, evidence of previous surgery, and a mixed radiolucent/radiodense lesion. On close inspection, the bone has a ground-glass appearance (Fig. 7-4A.)His previous surgical records included a pathology report describing fibrous dysplasia. Given his symptoms and the varus deformity, a corrective osteotomy with intramedullary fixation was performed (Fig. 7-4B). The patient has since enjoyed a marked reduction in his symptoms.
Metastatic Disease of the Femoral Neck
Metastatic malignant disease commonly affects the proximal femur and acetabulum. The role of the orthopaedic surgeon in the management of a patient with metastatic disease is to establish the diagnosis, identify those patients at risk for fracture, and reconstruct bone defects following fracture (Table 7-2).
The management of a pathologic fracture is very different compared with a traumatic fracture in normal bone. Every effort must be directed to the restoration of the patient's function and relief of pain as quickly as possible. Fixation choices should include those options that permit immediate full weight bearing, with the assumption that the fracture itself will never heal. The surgeon must recognize that further local progression of the metastatic lesion may occur.
Femoral neck metastatic disease is rarely treated with retention of the femoral head. Curettage, cementation, and screw fixation of femoral neck lesions is rarely performed. Reduction and fixation of femoral neck fractures should not be performed. These lesions are best managed with either a total hip arthroplasty or hemiarthroplasty. Consideration should be given to using a long cemented stem. This permits predictable immediate fixation, allows for postoperative radiation therapy, and extends the scope of the reconstruction to prophylactically strengthen the remaining femur. The management of an impending femoral neck fracture is the same as for a completed fracture. However, palliative radiotherapy may be offered first as some patients may have a very good response and thus avoid surgery.
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TABLE 7-2 Metastatic Bone Disease Basic Surgical Principles |
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Case Presentation
The patient is a 56-year-old woman with known metastatic breast cancer. She has had increasing right hip pain for the past month. The pain was initially present only with weight bearing, but it is now present at rest and she is using crutches and a wheelchair. She has had radiation therapy to that area 4 weeks ago. Her physical exam demonstrated an otherwise healthy-appearing female, but her hip examination revealed a painful range of motion. Her plain radiographs and CT scan show widespread disease affecting the head, neck, and proximal femur. The patient has failed radiation therapy and is at risk of fracture. The intent of treatment is to fix the problem predictably, permit immediate return to function, and avoid future problems related to progression of the disease. Consequently, an arthroplasty was chosen. In this case, a total hip arthroplasty was performed; a hemiarthroplasty would work as well, but a total hip avoids the possibility of a painful hemiarthroplasty in a young patient. A long cemented stem was chosen to permit predictable immediate fixation, antibiotic delivery, and prophylactic stabilization of as much of the femur as possible (Fig. 7-5A–C).
Osteoid Osteoma
Osteoid osteoma is a benign bone tumor with an often characteristic presentation. The lesion is typically ≤1 cm in diameter. It is characterized by a radiolucent nidus with surrounding reactive bone formation. The diagnosis is easy to make histologically.
Epidemiology
This lesion can occur at any age but is more common in children and young adults, with a male predilection of two to one; it can occur in any bone. The lesion produces prostaglandins, which mediate pain and produce new bone formation. Aspirin and other anti-inflammatories block the production of prostaglandin, hence controlling the symptoms.
Presentation
Patients classically present with a deep distressing throbbing pain, typically worse at night. The pain is particularly responsive to aspirin, something patients often stumble on by themselves. Patients may medicate themselves to the
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point of developing tinnitus. If the tumor is present in the neck or head of the femur, it can present with typical pain as well as an irritable hip.
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Figure 7-5 A: Multiple radiolucent destructive lesions affecting the femoral head and neck B: CT scan demonstrating diffuse disease from metastatic breast carcinoma C: Pose operative radiograph, long stemmed cemented total hip arthroplasty. |
Radiographic Evaluation
Plain radiographs are often diagnostic, with the lesion classically demonstrating a radiolucent nidus with a surrounding area of reactive bone produced by prostaglandin production. Technetium bone scanning typically shows a hot spot. A bone scan is helpful when the lesion is not readily apparent on plain radiographs. Computed tomography is often diagnostic and is helpful in locating the lesion in difficult anatomic locations. Dynamic enhanced (gadolinium angiography) magnetic resonance imaging is helpful in differentiating an osteoid osteoma from other similar-appearing lesions. The nidus of an osteoid osteoma will show a bright blush from the gadolinium.
Osteoid osteoma involving the hip joint can have a dramatic appearance on magnetic imaging with edema involving the bone and surrounding soft tissues. A prominent and florid synovial reaction can occur if the lesion is intra-articular, on the surface of the femoral neck, or near the synovium. This can mimic other synovial proliferative disorders both clinically and radiographically.
Treatment
The treatment of choice when medical management fails or is not acceptable is radiofrequency ablation. With the precise guidance of computed tomographic fluoroscopy under general anaesthesia, a radiofrequency needle is placed within the center of the nidus and heated to 90°C for 6 minutes. The morbidity is low, the failure rate is low, and typically the patient is painfree the next day. A biopsy is done at the time of needle insertion, but because of the small size of the needle used, representative tissue is seen only 40% of the time. More than 95% of patients can be expected to be cured with a single treatment. The risk of relapse is low. The patient may resume full unrestricted activity immediately following treatment.
Case Presentation
The patient is a 12-year-old boy with an 8-month history of intermittent hip pain. It has been increasing over the last 2 months and is particularly worse at night. The patient has been taking ibuprofen with moderate pain relief. Physical examination reveals a marked restriction in range of motion of the hip and muscular atrophy. MR imaging reveals a lesion on the neck of the femur with an effusion, synovitis, and surrounding edema (Fig. 7-6A). The image was initially suggestive of either infection or Ewing sarcoma. The clinical and radiographic features were more consistent with osteoid osteoma with a brisk inflammatory reactive response (Fig. 7-6B–D). The patient was treated with a CT-guided radiofrequency thermal ablation (Fig. 7-6E). The patient had an excellent response and remains symptomfree 2 years later.
Chondroblastoma
Chondroblastoma is a rare benign cartilaginous tumor that classically arises in the epiphysis and accounts for <1% of all primary bone tumors. Most tumors arise in patients with active epiphyses, and the most common location is the proximal humerus, followed by the knee and hip.
Presentation
Patients typically present with symptoms; it is rarely an incidental finding. Symptoms include pain, swelling, and a painful range of motion.
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Radiologic Evaluation
The lesion is typically radiolucent with a sharply defined reactive rim. The lesion may show subtle areas of calcification within it, and its location is usually indicative of the diagnosis. The lesion is hot on bone scan, and generalized uptake around the affected joint is not uncommon.
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Figure 7-6 A: T2-weighted MR image demonstrating marrow signal changes in the proximal femur with a large effusion. B: Axial MR image demonstrating the nidus. C: Dynamic enhanced MRI showing characteristic blush from gadolinium. D–E: CT images demonstrating the nidus and placement of the radiofrequency probe. |
Computed tomography is helpful in demonstrating intralesional calcification and better defines the plain radiographic appearance. Magnetic resonance imaging demonstrates a homogenous hypointense appearance on T1-weighted imaging and variable to hyperintense signal on T2-weighted images. A secondary aneurysmal bone cyst component is not uncommon with chondroblastoma. This is evident by an area of high signal on T2 suggestive of blood and fluid levels on both MRI and CT scans. A large amount of reactive edema in the bone and synovitis in the joint is often seen as well and explains the symptoms of pain and joint irritability seen with often relatively small lesions. Giant cell tumor and clear cell chondrosarcoma are in the differential, but these tend to occur in older patients. Clear cell chondrosarcoma can have a similar MRI appearance to chondroblastoma but is usually in an older age group, is larger, and extends beyond the epiphysis.
Treatment
Chondroblastoma usually responds well to intralesional curettage and bone grafting. This disorder has a local
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recurrence rate of 5% to 15%, largely depending on the thoroughness of resection. Chondroblastoma of the femoral head presents a challenge in all aspects of its management. In patients in whom the diagnosis is unlikely to be a clear cell chondrosarcoma, treatment can consist of open biopsy, frozen section, and immediate curettage and bone grafting. The surgical approach can include arthrotomy, surgical dislocation, and approaching the lesion from a window in the neck below the articular cartilage or a transtrochanteric tunnel through the neck of the femur. Open arthrotomy has a higher morbidity but would most likely allow for a more complete curettage. A transtrochanteric approach has a lower morbidity but a higher chance of local recurrence. The older patient with a radiolucent epiphyseal tumor is a more difficult problem. The differential diagnosis would include a clear cell chondrosarcoma. A biopsy has the potential to contaminate either the joint or the intertrochanteric region depending on the approach. If the index of suspicion is very high or if the femoral head is so involved and the joint is not contaminated, an excisional biopsy and total hip arthroplasty can be considered on very rare occasions.
Case Presentation
The patient is a 19-year-old female college student who presents with a 4-month history of left hip pain. Activity related, it is increasing in severity and is present at rest and at night. Physical examination reveals a limp and a generally diminished range of motion of her hip with severe pain at the extreme of motion. Plain radiographs demonstrate a radiolucent lesion arising solely in the epiphysis of the proximal femur (Fig. 7-7A). MRI demonstrates a well-defined lesion with a modest amount of edema (Fig. 7-7B, C). The clinical and radiographic features strongly favored a chondroblastoma. The patient was treated by an intralesional curettage and bone grafting. This was done via a transtrochanteric approach with fluoroscopic guidance. A core of bone was removed with a 16-mm trephine. The bone was reserved, and the curettage was guided by fluoroscopy with direct visualization using a laparoscope through the tunnel. Once completed, the core was reinserted into the defect and the lateral deficiency was grafted with morselized allograft. The postoperative MRI at 18 months shows the transtrochanteric approach and the resolution of the lesion with healing of the graft. (Fig. 7-7D–E).
Septic Arthritis with Pre-Existing Joint Disease
Septic arthritis in adults occurs infrequently. Occasionally, severe joint destruction can occur, most often when the diagnosis is delayed. This problem usually is managed with a resection arthroplasty and a delayed total hip arthroplasty.
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Epidemiology
Approximately 20,000 cases per year occur in the United States. The incidence is increased in immunocompromised and elderly patients with comorbidities. Forty-five percent of patients are older than 65 years of age. The morbidity and mortality rate is dependent on the organism.
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Figure 7-7 A: Plain radiograph showing a subtle radiolucent epiphyseal lesion. B–C: MR image demonstrating marrow edema involving the head and neck. D: Two-year postoperative MRI. The track made by the trephine to obtain access to the lesion is seen on this image. The bone graft is evident in the cavity. E: The corresponding plain radiograph showing the grafted lesion. |
Diagnosis
This disorder may present with a range of symptoms from subtle joint irritability to fulminant systemic sepsis. Typically, the presentation is monarticular and is usually acute in onset. Patients with pre-existing joint disease report a sudden increase in their joint symptoms.
Physical Examination
On examination, typically the hip is guarded in flexion and external rotation and any motion of the joint is extremely painful. With severely immunocompromised patients, the signs may be less obvious, and in patients with severe sepsis, the diagnosis of polyarticular sepsis may be difficult to make. Ninety percent of cases are monarticular.
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Diagnosis
The plain radiographs usually are normal. An MRI is very helpful in demonstrating an effusion with reactive edema. Patients with pre-existing hip pathology can present more of a challenge radiographically, as the underlying arthritic problem can be the source of pain.
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Figure 7-8 A: Plain radiograph showing advanced avascular necrosis and soft tissue swelling around the right hip joint. B: Interval antibiotic spacer prosthesis. The patient was allowed full weight bearing on this device. C: Subsequent definitive reconstruction with a cementless implant. |
Aspiration for culture, cell count, and joint fluid analysis is the test of choice. Treatment is based on the clinical findings and the preliminary joint fluid analysis. If the suspected diagnosis is sepsis, the treatment is arthrotomy, debridement, and antibiotic therapy.
Various approaches can be used, but I prefer an anterolateral approach, excision of the anterior capsule of the hip, and a synovectomy without dislocating the hip. In patients who have pre-existing end-stage hip disease or those patients with persistent infection with a destroyed hip joint, I resect the femoral head and insert a primary functionalantibiotic-impregnated spacer total hip prosthesis. Various spacers are now available. I prefer to use a therapeutic dosage of antibiotics in the bone cement, typically 4.8 g of gentamicin and 2.0 g of vancomycin per 40-g package of cement. The patient receives 6 weeks of parenteral antibiotics followed by a definitive arthroplasty, usually a minimum of 8 weeks later. The second stage can be deferred indefinitely in patients who are elderly and frail and have other significant comorbidities.
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Case Presentation
The patient is a 68-year-old man with a recent diagnosis of a low-grade gastrointestinal (GI) lymphoma and has been receiving chemotherapy. He has had right hip pain for the past 5 months. It began suddenly and has been getting worse. Over the past 3 days the pain has become severe, and he has been unable to get out of bed for the past 24 hours. On physical examination he appears unwell and his temperature was 39.5°C. His hip is extremely painful to any motion, and he has marked tenderness in his right groin. His hip was aspirated, revealing a white count of 65,000 cells with 80% nucleated polymorphonuclear cells. A Gram stain revealed Gram-positive cocci. His plain radiograph showed stage four avascular necroses (Fig. 7-8A). The patient was treated with surgical debridement and a two-stage total hip replacement, first using a functional antibiotic-impregnated spacer prosthesis (Fig. 7-8B). He was treated with 6 weeks of intravenous vancomycin and oral rifampin for methicillin-resistant staph aureus. He continued his chemotherapy, and initially it was planned to leave the temporary device in indefinitely. He did well with his lymphoma, was allowed to be as active as possible, and finally a year later his hip was replaced with a definitive prosthesis (Fig. 7-8C).
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