Adam Mitchell

Pseudotumors in Association with Well-functioning Metal-on-metal Hip Prostheses: A Case-control Study Using Three-dimensional Computed Tomography and Magnetic Resonance Imaging

INTRODUCTION Many papers have been published recently on the subject of pseudotumors surrounding metal-on-metal hip resurfacing and replacement prostheses. These pseudotumors are sterile, inflammatory lesions within the periprosthetic tissues and have been variously termed masses, cysts, bursae, collections, or aseptic lymphocyte-dominated vasculitis-associated lesions (ALVAL). The prevalence of pseudotumors in patients with a well-functioning metal-on-metal hip prosthesis is not well known. The purpose of this study was to quantify the prevalence of pseudotumors adjacent to well-functioning and painful metal-on-metal hip prostheses, to characterize these lesions with use of magnetic resonance imaging, and to assess the relationship between their presence and acetabular cup position with use of three-dimensional computed tomography. METHODS We performed a case-control study to compare the magnetic resonance imaging findings of patients with a well-functioning unilateral metal-on-metal hip prosthesis and patients with a painful prosthesis (defined by either revision arthroplasty performed because of unexplained pain or an Oxford hip score of <30 of 48 possible points). Thirty patients with a painful hip prosthesis and twenty-eight controls with a well-functioning prosthesis were recruited consecutively. All patients also underwent computed tomography to assess the position of the acetabular component. RESULTS Thirty-four patients were diagnosed with a pseudotumor. However, the prevalence of pseudotumors in patients with a painful hip (seventeen of thirty, 57%) was not significantly different from the prevalence in the control group (seventeen of twenty-eight, 61%). No objective differences in pseudotumor characteristics between the groups were identified. No clear association between the presence of a pseudotumor and acetabular component position was identified. The Oxford hip score in the group with a painful hip (mean, 20.2; 95% confidence interval [CI], 12.7 to 45.8) was poorer than that in the control group (mean, 41.2; 95% CI, 18.5 to 45.8; p ≤ 0.0001). CONCLUSIONS A periprosthetic cystic pseudotumor was diagnosed commonly (in thirty-four [59%] of the entire study cohort) with use of metal artifact reduction sequence (MARS) magnetic resonance imaging in this series of patients with a metal-on-metal hip prosthesis. The prevalence of pseudotumors was similar in patients with a well-functioning hip prosthesis and patients with a painful hip. Pseudotumors were also diagnosed commonly in patients with a well-positioned acetabular component. Although magnetic resonance imaging is useful for surgical planning, the presence of a cystic pseudotumor may not necessarily indicate the need for revision arthroplasty. Further correlation of clinical and imaging data is needed to determine the natural history of pseudotumors to guide clinical practice.

The painful metal-on-metal hip resurfacing

We carried out metal artefact-reduction MRI, three-dimensional CT measurement of the position of the component and inductively-coupled plasma mass spectrometry analysis of cobalt and chromium levels in whole blood on 26 patients with unexplained pain following metal-on-metal resurfacing arthroplasty. MRI showed periprosthetic lesions around 16 hips, with 14 collections of fluid and two soft-tissue masses. The lesions were seen in both men and women and in symptomatic and asymptomatic hips. Using three-dimensional CT, the median inclination of the acetabular component was found to be 55 degrees and its positioning was outside the Lewinnek safe zone in 13 of 16 cases. Using inductively-coupled plasma mass spectrometry, the levels of blood metal ions tended to be higher in painful compared with well-functioning metal-on-metal hips. These three clinically useful investigations can help to determine the cause of failure of the implant, predict the need for future revision and aid the choice of revision prostheses.

Systematic Comparison of the Early Outcome of Angioplasty and Endarterectomy for Symptomatic Carotid Artery Disease

Background and Purpose —Endoluminal treatment is being increasingly used for carotid artery disease. The aim of this study was to compare the stroke and death risk within 30 days of endovascular treatment or endarterectomy for symptomatic carotid artery disease. Methods —A systematic comparison of the 30-day outcome of angioplasty with or without stenting and endarterectomy for symptomatic carotid artery disease reported in single-center studies, published since 1990, was performed. Results —Thirty-three studies (13 angioplasty and 20 carotid endarterectomy) were included in this analysis. Carotid stents were deployed in 44% of angioplasty patients. Mortality within 30 days of angioplasty was 0.8% compared with 1.2% after endarterectomy (OR 0.68, 95% CI 0.43 to 1.05; P =0.6). The stroke rate was 7.1% for angioplasty and 3.3% for endarterectomy (OR 2.22, CI 1.62 to 3.04; P <0.001), while the risk of fatal or disabling stroke was 3.2% and 1.6%, respectively (OR 2.09, CI 1.3 to 3.33; P <0.01). The risk of stroke or death was 7.8% for angioplasty and 4% for endarterectomy (OR 2.02, CI 1.49 to 2.75; P <0.001), while disabling stroke or death was 3.9% after angioplasty and 2.2% after endarterectomy (OR 1.86, CI 1.22 to 2.84; P <0.01). Conclusions —In the treatment of symptomatic carotid artery disease, the risk of stroke is significantly greater with angioplasty than carotid endarterectomy. At present, carotid angioplasty is not recommended for the majority of patients with symptomatic carotid artery disease.

Magnetic Resonance Imaging Findings in Painful Metal-On-Metal Hips A Prospective Study

Metal artifact reduction sequence magnetic resonance imaging findings are reported in a prospective series of 31 patients with unexplained painful metal-on-metal (MOM) hips. The abnormalities identified were fluid collection (20 patients), solid mass (2 patients), moderate to severe muscle atrophy (23 patients), and muscle edema (8 patients). In conclusion, soft tissue lesions and muscle atrophy appear to be prevalent in unexplained painful MOM hips. Metal artifact reduction sequence magnetic resonance imaging may be useful to diagnose and monitor at-risk hips but requires validation in well-functioning MOM hips before it can guide clinical decision making.

Revision of metal-on-metal hip arthroplasty in a tertiary center: A prospective study of 39 hips with between 1 and 4 years of follow-up

Background and purpose Operative findings during revision of metal-on-metal hip arthroplasty (MOMHA) vary widely and can involve massive soft tissue and bone disruption. As a result, planning of theater time and resources is difficult, surgery is challenging, and outcomes are often poor. We describe our experience with revision of MOMHA and provide recommendations for management. Patients and methods We present the findings and outcomes of 39 consecutive MOMHAs (in 35 patients) revised in a tertiary unit (median follow-up time 30 (12–54) months). The patients underwent a preoperative work-up including CT, metal artifact reduction sequence (MARS) MRI, and blood metal ion levels. Results We determined 5 categories of failure. 8 of 39 hips had conventional failure mechanisms including infection and impingement. Of the other 31 hips, 14 showed synovitis without significant disruption of soft tissue; 6 had a cystic pseudotumor with significant soft tissue disruption; 7 had significant osteolysis; and 4 had a solid pseudotumor. Each category of failure had specific surgical hazards that could be addressed preoperatively. There were 2 reoperations and 1 patient (2 hips) died of an unrelated cause. Median Oxford hip score (OHS) was 37 (9–48); median change (ΔOHS) was 17 (–10 to 41) points. ΔOHS was similar in all groups—except those patients with solid pseudotumors and those revised to metal-on-metal bearings, who fared worse. Interpretation Planning in revision MOMHA is aided by knowledge of the different categories of failure to enable choice of appropriate personnel, theater time, and equipment. With this knowledge, satisfactory outcomes can be achieved in revision of metal-on-metal hip arthroplasty.

Chlamydia pneumoniae Does Not Influence Atherosclerotic Plaque Behavior in Patients With Established Carotid Artery Stenosis

Background and Purpose Research for infectious agents in the etiology of atherosclerosis has identified Chlamydia pneumoniae as a possible candidate. While there is evidence of an association between presence of this microorganism and atherosclerosis, it is unclear whether infection has a genuinely etiologic role in this disease, whether its presence influences clinical outcomes, and, if so, at which stages of disease this occurs. We have approached this issue in patients with advanced carotid artery atherosclerosis using molecular biological detection methods and clinically relevant indicators of pathology in carotid artery atheroma to determine whether the presence of C pneumoniae correlates with plaque instability. Methods C pneumoniae was detected with the use of a sensitive nested polymerase chain reaction. Preoperative embolization and preoperative infarcts were recorded with the use of transcranial Doppler insonation of the middle cerebral artery and cerebral CT, respectively. Results C pneumoniae DNA was detected in 25.5% of a cohort of 98 symptomatic patients. There was no significant difference in plaque stability as measured by embolization rates between the chlamydial-positive and -negative specimens. There was also no correlation between the number of ipsilateral hemispheric infarcts in the territory of the middle cerebral artery and chlamydial status. Conclusions This study confirms that C pneumoniae is a common finding in atherosclerotic plaques of the carotid artery but suggests that the presence of the infectious organism has little detectable impact on plaque instability when measured by clinically significant markers. This raises important questions for the rationale of antibiotic therapy in atherosclerosis.

Clinical Outcome Following Infra-Inguinal Percutaneous Transluminal Angioplasty for Critical Limb Ischemia

AbstractObjective: The aim of this study was to assess the efficacy and durability of infra-inguinal PTA in patients with CLI, in terms of clinical outcome. Design: Retrospective study of 50 consecutive patients with CLI that were exclusively treated by infra-inguinal PTA. Methods: The indications for intervention were rest pain in seven (14%) patients, non-healing ulcers in 27 (54%), and gangrenous lesions in 16 (32%). Thirty-three (66%) of these patients presented with a single arterial lesion, and the remaining 17 (34%) with multilevel arterial lesions. Kaplan-Meier analysis was used to assess survival, patency, limb-salvage rates, and amputation-free survival. Results: A total of 67 endovascular procedures were performed and 59 (88.1%) of them were considered to be technically successful. The median follow-up period was 12 months (interquartile range: 17 months). The 30-day mortality was 4%, while the cumulative survival rates at 12, 24, and 36 months were 73%, 67%, and 59%, respectively. The cumulative primary patency rates at 12 and 24 months were 63% and 52%, respectively, and remained unchanged thereafter. The estimated secondary patency rate was 72% at 36 months. There was only one below-knee amputation in the patients that were treated exclusively with infra-inguinal PTA. The cumulative amputation-free survival at the same period was estimated at 60%. Conclusions: Infra-inguinal PTA had a good early and late outcome in this series of patients with a limited life expectancy. These results are comparable to historical results of surgical revascularization in the treatment of CLI. There is need for a randomized study to determine the primary optimal interventional approach for patients with CLI.

Endovascular Treatment of Renal Artery Stenosis

Significant changes have occurred in the treatment of renal artery disease over the past few years. Although excellent clinical results can be obtained with surgery, percutaneous transluminal renal angioplasty has proved similarly efficacious and is now the treatment of choice for nonostial atherosclerotic stenoses and fibromuscular dysplasia. The introduction of stents has become a valuable adjunctive therapy for postangioplasty restenosis and dissection.

Non-operative management of a complete anterior cruciate ligament injury in an English Premier League football player with return to play in less than 8 weeks: applying common sense in the absence of evidence

This case report illustrates and discusses the non-operative management of a complete anterior cruciate ligament (ACL) injury in an English Premier League football player, his return to play within 8 weeks and problem-free follow-up at 18 months post injury. When non-operative verses surgical ACL reconstruction is considered there are many fundamental gaps in our knowledge and currently, at elite level, there are no cases in cutting sports within the literature to guide these decisions. When the norm is for all professional footballers to be recommended surgery, it will be very challenging when circumstances and patient autonomy dictate a conservative approach, where prognosis, end points and risk are unclear and assumed to be high. This case challenges current dogma and provides a starting point for much needed debate about best practice, treatment options, research direction and not just at the elite level of sport.

Hydronephrosis after Embolization of Internal Iliac Artery Aneurysms

The treatment of internal iliac artery aneurysms is aimed at the prevention of rupture. Traditionally, this is undertaken surgically; however, endovascular techniques are an acceptable alternative and these techniques are also not without complication. Herein, the authors describe the endovascular treatment of two patients with internal iliac aneurysms. Although the treatments were initially successful, both patients presented with ureteric obstruction and hydronephrosis 2 months later.