Radiological evaluation of painful total hip replacement

Ninety-four cases of clinically failed, cemented, total hip prostheses requiring surgery were reviewed to determine the accuracy of preoperative plain radiography, culture of aspirated fluid, arthrography, and bone scanning. When radiopaque cement had been used to embed the prosthesis, plain radiography was highly accurate in detecting a loose femoral component, less so in detecting a loose acetabular component. Culture of aspirated fluid was accurate in diagnosing infection. A positive arthrogram identified loosening with good accuracy; however, a negative arthrogram did not reliably exclude loosening. 99mTc bone scans frequently differentiated loosening from loosening with infection. The suggested sequence of diagnostic tests is plain radiography followed by bone scanning. If the bone scan shows diffuse augmented uptake, culture of aspirated fluid followed by arthrography is indicated.     

Digital subtraction arthrography in preoperative evaluation of painful total hip arthroplasty

 Objective. The objective of this clinical study was to define the diagnostic value of plain radiography, digital subtraction arthrography and two-phase bone scintigraphy in patients with clinically loose or infected hip prostheses. Design. Digital subtraction arthrograms, scintigrams and plain radiographs of 70 consecutive patients who underwent revision hip arthroplasty were scored individually and in masked fashion for the presence or absence of features indicating loosening of femoral and/or acetabular components. The operative findings acted as the gold standard. Results. Digital subtraction arthrography was best (P<0.001) for predicting a loose acetabular component, while no significant additional predictive value was found for plain radiographs (P=0.24) and scintigraphy (P=0.27). Digital subtraction arthrography was also the most important modality for predicting a loose femoral component (P=0.001), while the plain radiograph was of significant (P=0.04) additional value and scintigraphy was of no additional value (P=0.13) on multivariate analysis. Conclusion. Digital subtraction arthrography gives the best results in the prediction of loosening of acetabular and femoral components. Plain radiographs give additional information on loosening of the femoral component, but scintigraphy offers no additional advantage.     

Arthrography of painful hips following arthroplasty: digital versus plain film subtraction

Digital and manual subtraction images obtained during the arthrographic evaluation of 78 painful hip prostheses were reviewed retrospectively. Revision arthroplasty was performed in 53 of these cases, and the arthrographic and surgical findings were correlated. The digital and manual subtraction images were evaluated without knowledge of the surgical results using established criteria for component loosening. Digital subtraction arthrography of the femoral component demonstrated a 96% sensitivity and 100% specificity for the diagnosis of component loosening. Sensitivity and specificity for acetabular component loosening were 83% and 80%, respectively. Plain film subtraction of the femoral component demonstrated a 79% sensitivity and 100% specificity; the sensitivity and specificity for the acetabular component were 75% and 80%, respectively. The difference between detection of femoral component loosening on digital as opposed to manual subtraction images was statistically significant (P<0.05). This study demonstrates that digital subtraction improves the evaluation of femoral component loosening in painful hip prostheses.     

Osteochondritis dissecans: analysis of mechanical stability with radiography, scintigraphy, and MR imaging

Twenty-one joints with stable (n = 9) or loose (n = 12) osteochondritis dissecans (OCD) lesions were examined in 15 subjects with plain radiography, three-phase bone scintigraphy, and magnetic resonance (MR) imaging. The lesion size and the thickness of the sclerotic margin as measured on plain radiographs were good parameters for predicting loosening. However, bone scintigraphy was more sensitive and specific in determining the mechanical stability of OCD lesions. MR imaging permitted direct visualization of loosening and fragment displacement; the latter permits differentiation of in situ loosening from a grossly unstable lesion. The noninvasive nature of bone scintigraphy and MR imaging makes them potentially preferable diagnostic modalities to arthrography for evaluating the mechanical status of OCD lesions.     

Plain film and arthrographic findings in painful total hip arthroplasties with surgical correlation

The plain films and arthrograms performed on 42 painful cemented hip arthroplasties in 40 patients were reviewed and the radiological findings compared to the surgical assessment of component stability. All radiography, which included Judet views in the plain films, was reviewed without knowledge of the surgical findings and without comparison with previous studies. Criteria for the detection of loosening of cemented femoral and acetabular components were predetermined. The accuracy of plain film assessment of acetabular component stability was increased significantly (p less than 0.05) by including oblique views in the plain film assessment. The accuracy of assessment of acetabular component stability on plain films was 88%, on arthrography 90% and, with both studies combined, was 98%. Femoral component stability was assessed accurately on 90% of plain films and 90% of arthrograms, and this was not improved by combining the studies. The difficulty of detecting low grade infections is discussed with results of pseudocapsule aspiration.     

The use of [18 F]fluorodeoxyglucose positron emission tomography to differentiate between synovitis,loosening and infection of hip and knee prostheses

Pain is a common unspecific symptom in orthopaedic prosthetics. The accurate differentiation between synovitis, loosening or infection is often difficult with conventional X-rays, arthrography or bone scintigraphy. Because of the high glucose uptake of inflammatory cells, [18F]fluorodeoxyglucose (18F-FDG) is an appropriate tracer for the evaluation of suspected inflammation or infection. In this preliminary study we describe 18F-FDG PET findings in patients referred for evaluation of painful hip or knee prostheses. We studied 23 patients with 28 prostheses, 14 hip and 14 knee prostheses, who had a complete operative or clinical follow-up. 18F-FDG PET scans were obtained with an ECAT EXACT HR+ PET scanner. High glucose uptake in the bone prostheses interface was considered as positive for infection, an intermediate uptake as suspect for loosening, and uptake only in the synovia was considered as synovitis. The imaging results were compared with operative findings or clinical outcome. PET correctly identified three hip and one knee prostheses as infected, two hip and two knee prostheses as loosening, four hip and nine knee prostheses as synovitis, and two hip and one knee prostheses as unsuspected for loosening or infection. In three patients covered with an expander after explantation of an infected prosthesis PET revealed no further evidence of infection in concordance with the clinical follow-up. PET was false negative for loosening in one case. Our preliminary results suggest that FDG PET could be a useful tool for differentiating between infected and loose orthopaedic prostheses as well as for detecting only inflammatory tissue such as synovitis.     

Correlation between radiologic and clinical findings in Charnley total hip replacement. A 10-year follow-up study

The main purpose of this study was to evaluate the relationship between the radiologic findings in clinically successful Charnley total hip replacements (THR) at an average of five years postoperatively ('5-year follow-up') and the clinical result 10 to 14 years after operation ('10-year follow-up'). The study included 150 arthroplasties graded as clinically successful at the 5-year follow-up despite radiologic loosening of the femoral component in 41 per cent and of the acetabular component in 7 per cent. The incidence of clinical failure between the two follow-ups was 7 per cent (10 hips). Only 2 per cent (3/125) of THRs with intact components or a loose stem with migration not exceeding 4 mm became failures. Clinical failures resulted in 28 per cent (7/25) of THRs with more extensive loosening of the stem or with a loose socket. At the 10-year follow-up 47 per cent of the femoral and 13 per cent of the acetabular components were loose. Progression of loosening of the femoral stem occurred in 63 per cent and of the socket in 73 per cent between the two follow-ups. The incidence of loosening of the stem showed a significant correlation both with the extent of cementation distal to the tip and with the orientation of the prosthesis in the sagittal plane.     

Complications of total hip arthroplasty: MR imaging-initial experience

PURPOSE: To investigate the use of standard magnetic resonance (MR) imaging sequences with simple parameter modifications for the detection and characterization of total hip arthroplasty (THA) complications. MATERIALS AND METHODS: An initial phantom study was performed with cobalt-chrome and titanium prostheses to establish the imaging parameters for a subsequent clinical study. In the clinical study, coronal and transverse MR imaging of 14 THA prostheses was performed before and after intravenous contrast material administration in 12 patients who were being considered for revision arthroplasty. The images were reviewed for evidence of juxtaarticular or periprosthetic abnormalities, patterns of contrast enhancement, and quality of periprosthetic tissue depiction. RESULTS: Phantom study results showed improved periprosthetic tissue depiction with use of thin sections, increased frequency-encoding gradient strength, and fast spin-echo sequences. The clinical study results demonstrated periprosthetic abnormalities in 11 cases: mechanical loosening in two cases (including one case with an associated periprosthetic fracture); granulomatosis, eight; and infection, one. In 100% of cases, tissue depiction around the femoral component was judged to be of "diagnostic quality." Tissue depiction around the acetabular component was of diagnostic quality in five (36%) cases. In all seven surgically confirmed cases, a correct diagnosis was made preoperatively with MR imaging. CONCLUSION: By using simple modifications to standard MR imaging sequences, diagnostic-quality MR imaging of THA complications can be performed, particularly around the femoral prosthetic stem.     

Radionuclide imaging of musculoskeletal infection: conventional agents

The diagnosis of musculoskeletal infection can be clinically challenging, and radionuclide imaging is often performed as part of the diagnostic workup. Conventional studies include bone scan, gallium imaging, and labeled leukocyte imaging. No single test is equally efficacious in all situations, and thus the procedure(s) performed should be optimized for the individual patient. Three-phase bone imaging, readily available and relatively inexpensive, is very accurate in unviolated bone. In the setting of underlying osseous abnormalities, however, the specificity of the test decreases. Four-phase bone, sequential bone/gallium, and labeled leukocyte imaging all have been used in an effort to enhance specificity. Labeled leukocyte imaging is the radionuclide procedure of choice for diagnosing so-called complicating osteomyelitis such as infected joint prostheses, diabetic pedal osteomyelitis, and infection of the neuropathic joint. To maximize the accuracy of the study, complementary bone marrow imaging often must be performed. Labeled leukocyte imaging is of limited value in spinal osteomyelitis, however, because this entity often presents as a nonspecific photopenic defect on white cell studies. The conventional radionuclide study for evaluating spinal osteomyelitis is gallium imaging, which should be performed regardless of the findings on a contemporaneous bone scan. The reasons for this are as follows: Gallium improves the specificity of the bone scan; gallium detects accompanying soft tissue infection, whereas the bone scan does not, and gallium may be more sensitive than the bone scan in elderly patients.     

A simple method of identifying loosening or infection of hip prostheses in nuclear medicine

Joint replacement is now established as a reliable orthopaedic procedure for the relief of many painful degenerative conditions of the hip. When successful it enhances hip movement and relieves pain with a concomitant improvement in function and well being for the patient. When unsuccessful the persistence of pain usually signifies loosening or infection. Loosening may result from mechanical failure or infection. Accurate distinction between septic and aseptic loosening is important for planning and executing surgical intervention. The experience of the Department of Nuclear Medicine in Coventry assessing pathology in painful hip prostheses was retrospectively reviewed in 47 patients. These patients were imaged from 1985 to 1987 and all had good clinical follow-up enabling the diagnosis of loosening, infection or normal to be made with confidence. All patients had three phase bone imaging and some had additional gallium imaging. The images were reviewed with particular emphasis on the pattern of uptake in the late bone image and congruence of abnormal uptake in the early bone image and gallium image. It is concluded that for the majority of patients simple three phase bone imaging will provide the required diagnostic information.     

Radiography, radionuclide imaging, and arthrography in the evaluation of total hip and knee replacement

Twenty patients with 21 total joint replacements including 17 hips and 4 knees were studied by plain film radiography, radionuclide imaging, and subtraction arthrography to evaluate these procedures for assessing prosthetic complications. Surgery was performed in 14 patients and confirmed loosening of 8 femoral and 7 acetabular hip prosthesis components and 1 femoral and 4 tibial knee prosthesis components. Plain films suggested loosening of only 9 hip components and no knee components. In contrast, radionuclide imaging and subtraction arthrography were considerably more effective in demonstrating loosening as well as other causes of the painful total joint prosthesis.     

CT与常规X线诊断髋关节创伤的对比分析

目的比较CT与X线平片对髋关节创伤的诊断效能。方法就76例髋关节创伤病例进行X线平片和CT检查,比较两种检查方法对髋臼骨折、股骨头及股骨颈骨折、关节腔内游离碎骨、髋关节脱位及关节周围软组织损伤的诊断效能。结果CT在髋臼骨折的分型诊断、发现股骨头隐匿性骨折和关节腔内游离碎骨等方面优于X线平片,CT还能显示髋关节积液、积血及关节周围软组织肿胀等形态变化。结论CT是全面评估髋关节创伤的必要检查手段,其总体诊断效能优于X线平片。     

Avascular osteonecrosis of the acetabulum

 Objective. To investigate the possible occurrence of osteonecrosis in the acetabulum in patients with non-traumatic necrosis of the femoral head. Design and patients. One hundred and seventy-nine patients with non-traumatic femoral head necrosis were assessed by MRI and radiography for the presence of acetabular necrosis. Three criteria were established to differentiate between osteonecrosis and osteoarthritic changes: (1) heterogeneous morphology and irregular contours of the lesion; (2) typical demarcation lines of osteonecrosis; (3) deficient accumulation of intravenous gadolinium in the affected regions. Results. In four patients histological confirmation of acetabular necrosis was obtained. The MR analysis of 22 acetabula (9.5% of those examined) showed changes which suggested osteonecrosis. No cystic lesions were demonstrated in the subchondral bone of any patient. Two cases of acetabular necrosis were found without an ipsilateral femoral head necrosis. In two patients of the 14 who had undergone total hip replacement following necrosis of the femoral head, aseptic loosening of the acetabular component was found. Conclusion. The study suggests that acetabular necrosis may be an accompaniment to aseptic necrosis of the femoral head. Further work is required to assess its importance in premature loosening of the acetabular element of total hip arthroplasty.     

Cemented total hip prosthesis: radiographic and scintigraphic evaluation

Conventional radiographs, technetium-99m bone scans, and gallium-67 scans were reviewed in 44 patients who had undergone cemented total hip joint replacement and were imaged because of suspicion of prosthesis loosening or infection. A complete radiolucent line of 2 mm or wider along the bone-cement interface or metal-cement lucency on conventional radiographs was used as the criterion for prosthetic loosening with or without infection and proved to be 54% sensitive and 96% specific. Scintigraphic criteria for prosthetic loosening were increased focal uptake of the radiopharmaceutical for the femoral component and increased focal or diffuse uptake for the acetabular component. For bone scintigraphy, sensitivity was 73% and specificity was 96%. Combining the results of conventional radiographs and bone scans increased sensitivity to 84% and decreased specificity to 92% for the diagnosis of loosening, infection, or both. The study also showed that Ga-67 scintigraphy has a low sensitivity for the detection of infection.     

Colour Doppler ultrasound assessment of well-functioning mature arteriovenous fistulas for haemodialysis access

OBJECTIVE: To summarize and compare the diagnostic accuracy of contrast and subtraction arthrography in the assessment of aseptic loosening of total hip arthroplasties. DESIGN: This meta-analysis was performed using methods described by the Cochrane Methods Group on Systematic Reviews of Screening and Diagnostic Tests. We included original, English-language papers published between January 1975 to October 2004 that examined contrast-enhanced arthrography with or without subtraction for diagnosis of loosening of total hip prostheses. A qualitative and quantitative analysis was performed by two investigators. RESULTS: With regard to the acetabular component, pooled sensitivity and specificity for contrast arthrography was 70% (95% confidence interval, 52-84) and 74% (95% CI, 53-87), respectively. Subtraction arthrography had a significantly higher sensitivity of 89% (95% CI, 84-93) (p=0.01), with a similar specificity of 76% (95% CI, 68-82). For the femoral component, pooled sensitivity and specificity for contrast arthrography were 63% (95% CI, 53-72) and 78% (95% CI, 68-86). Pooled estimates for subtraction arthrography revealed a significantly higher sensitivity of 86% (95% CI, 74-93) (p=0.003). Specificity was 85% (95% CI, 77-91) and was similar to the data of contrast arthrography (p=0.23). CONCLUSION: Using the present data we found that the subtraction arthrography is a sensitive technique for detection of loosening of total hip prostheses, offering added value over contrast arthrography, especially for evaluation of the femoral component.     

Scintigraphic abnormalities in patients with painful hip replacements treated conservatively.

A retrospective review of the scintigraphic appearances of 98 painful hip replacements was made. 16 patients (16%) underwent revision surgery whereas in the remaining 82 hips (84%), symptoms settled with conservative management. 73 of these (89%) had at least one area of increased activity on delayed diphosphonate scintigraphy with 27% having increased activity in three or more areas around the femoral component. Hips with increased activity at the lesser trochanter and tip were less likely to undergo spontaneous resolution of symptoms. Uncemented prostheses were more likely to have multiple areas of increased activity. Abnormalities in dynamic bone scintigraphy and gallium studies were also seen in patients whose symptoms resolved without surgery. Whereas a normal bone scintigram indicates that loosening or infection is most unlikely, the presence of increased activity does not necessarily indicate a need for revision surgery, even when multiple areas are present. A period of conservative management should be considered before operative intervention is undertaken.     

Loose hip prosthesis. Appearance in radionuclide arthrography

Radionuclide arthrography has been found to be valuable in the diagnosis of a loose hip prosthesis. The appearance of one normal case with no loosening and two abnormal cases with loosening of femoral and acetabular components are described. To diagnose this difficult problem, radionuclide arthrography should be used more frequently.     

Arthroscintigraphic evaluation of the painful total hip prosthesis

Arthroscintigraphy was performed in 19 patients with a painful total hip prosthesis by injecting both Tc-99m sulfur colloid and iodinated radiographic contrast material intra-articularly. Scintigraphic and radiographic results correlated exactly in 15 patients, with one false-negative scintigram, one false-positive scintigram, and one false-negative arthrogram. One patient was evaluated by scintigraphy alone. Although arthroscintigraphy is potentially more sensitive than conventional arthrography in the detection of femoral component loosening, acetabular component loosening cannot be evaluated by scintigraphy alone. A combination of scintigraphy and conventional arthrography appears to be the most accurate imaging method in the evaluation of hip prosthesis loosening.     

Infected knee prosthesis: diagnosis with In-111 leukocyte, Tc-99m sulfur colloid, and Tc-99m MDP imaging

Forty-one possible cases of infected total knee prostheses studied with indium-111-labeled leukocyte scintigraphy were retrospectively reviewed. Twenty-four of the prostheses were studied with technetium-99m methylene diphosphonate bone scintigraphy and 19 with Tc-99m sulfur colloid marrow scintigraphy. Nine prostheses were infected, and 32 were uninfected. The accuracy of combined labeled leukocyte and sulfur colloid marrow imaging (95%) was higher than that of labeled leukocyte scintigraphy alone (78%), bone scintigraphy alone (74%), or combined labeled leukocyte and bone scintigraphy (75%). The authors conclude that combined labeled leukocyte and sulfur colloid imaging is an accurate method for diagnosis of infected knee prostheses. In this series, this technique was superior to labeled leukocyte and bone imaging, alone or in combination.     

Bone imaging after cementless press fit total hip arthroplasty

In view of the high rate of loosening of conventional cemented hip prostheses, cementless implants are gaining popularity in Europe and North America. Smooth-surfaced "press fit" prostheses are designed for autolocking in the femoral canal at the time of installation. Fifteen patients were prospectively followed by bone imaging with Tc-99m MDP at three-month intervals after cementless "press fit" hip arthroplasty to define the "normal" distribution of mechanical stress to the surrounding bone, as well as the incorporation of bone allografts used for reconstruction of resorption sites in cases of revision surgery.