Patellofemoral joint arthroplasty: patient selection,surgical technique and outcomes

Isolated patellofemoral arthritis is an increasingly recognized entity, and is usually associated with previous patellofemoral dysplasia or instability. Patellofemoral arthroplasty (PFA) has evolved significantly in recent years, both in terms of implant design and importantly in the understanding of appropriate patient selection. This review outlines the indications and investigations for PFA, provides a brief history of the development of contemporary implants, and presents the clinical outcomes for the prostheses most commonly used in the UK. In addition, it provides a detailed surgical technique for implantation of an onlay implant, with tips on how to optimize patellofemoral biomechanics and thus achieve a consistently good outcome.     

Effects of Nitroglycerin and Propranolol on the Distribution of Transmural Myocardial Blood Flow during Ischemia in the Absence of Hemodynamic Changes in the Unanesthetized Dog

Chronically instrumented awake dogs were used to study the effects of nitroglycerin and propranolol on the transmural distribution of myocardial blood flow during transient ischemia. Studies were carried out 7-14 d after implantation of an electromagnetic flowmeter probe and balloon occluder on the left circumflex coronary artery, placement of epicardial minor axis sonar crystals, and implantation of left atrial, left ventricular, and aortic catheters. The occluder was inflated to completely interrupt flow for 10 s followed by partial release to reestablish flow at 60% of the preocclusion level. During this partial release, which served as the control for the study, regional myocardial blood flow was measured with 7- to 10-mum radioactive microspheres. After control measurements, seven dogs were given nitroglycerin (0.4 mg i.v.) and eight dogs propranolol (0.2 mg/kg i.v.). 5 min later the occlusion and partial release sequence was repeated, and regional myocardial blood flow was measured when heart rate, aortic and left ventricular end-diastolic pressure, and minor axis diameter were unchanged from control values.The data values were selected so that total flow to the ischemic region during partial release after nitroglycerin or propranolol administration was not significantly different from flow during the control partial release. After nitroglycerin administration, endocardial flow (endo) in the ischemic region increased from 0.46+/-0.07 to 0.59+/-0.06 ml/min per g (P < 0.006); epicardial flow (epi) decreased from 0.78+/-0.09 to 0.70+/-0.08 ml/min per g (P < 0.04). The endo:epi ratio increased from 0.65+/-0.07 to 0.92+/-0.10 (P < 0.05). In contrast, administration of propranolol produced no significant change in transmural flow (endo, 0.42+/-0.02 and 0.46+/-0.03 ml/min per g; epi, 0.71+/-0.06 and 0.70+/-0.07 ml/min per g) or in the endo:epi ratio (0.60+/-0.03, 0.66+/-0.06) in the ischemic region.Nitroglycerin and propranolol produce different effects on the transmural distribution of blood flow to ischemic myocardium. Nitroglycerin can increase blood flow to the underperfused endocardium in the absence of alterations in heart size, hemodynamic parameters, and total transmural flow to the ischemic region. Under similar conditions, propranolol has no significant effect on the transmural distribution of blood flow to an ischemic region.     

Monitoring for undertransfusion

BACKGROUND: Most published reviews and audits of blood and blood component transfusion have focused on the issue of overtransfusion and on the inappropriate use of red cell components. There is growing concern that efforts to curb unnecessary transfusions may result in a trend toward undertransfusion of patients. There is little published information that addresses this issue or the magnitude of this practice. STUDY DESIGN AND METHODS: Undertransfusion was evaluated by examining the transfusion records from a 3-month period for 55 patients who met the study criteria of having either a hemoglobin level < 7 g per dL or a platelet count of < 10 × 10(9) per L. If the identified patient did not receive a transfusion within 24 hours of the reported hemoglobin level or platelet count, the medical record was reviewed by a resident physician. RESULTS: A total of 213 individual hemoglobin levels and platelet counts, representing the 55 patients, met our transfusion criteria. All except 8 of the identified patients received red cells and/or platelet transfusions. Reasons for not transfusing red cells included the patient's response to nutritional support and iron supplementation, refusal of blood, and noncompliance. Reasons for not transfusing platelets included falsely low platelet count because of platelet clumping in vitro, contraindication based on clinical diagnosis (e.g., immune thrombocytopenic purpura), and the patient's death before transfusion. CONCLUSION: Red cell and platelet transfusions were appropriately ordered for all patients who met the transfusion criteria. Undertransfusion is not a problem at this institution according to the criteria established. It is recommended that other institutions expand their blood utilization audits to include investigation for evidence of undertransfusion. Further research regarding the issue of undertransfusion is warranted and could be expanded to include other components.     

The relationship between physicians' self-reported target fasting blood glucose levels and metabolic control in type 2 diabetes. The QuED Study Group--quality of care and outcomes in type 2 diabetes

OBJECTIVE: To investigate the relationship between beliefs of physicians relative to intensive metabolic control in type 2 diabetes and levels of HbA1c obtained in a sample of their patients. RESEARCH DESIGN AND METHODS: Physicians' beliefs were investigated through a questionnaire sent to a sample of self-selected clinicians participating in a nationwide initiative aimed at assessing the relationship between the quality of care delivered to patients with type 2 diabetes and their outcomes. At the same time, physicians were asked to collect clinical data on a random sample of their patients, stratified by age (<65 vs. > or = 65 years). Mean HbA1c levels in the study population were thus evaluated according to target fasting blood glucose (FBG) used by their physicians. RESULTS: Of 456 physicians, 342 (75%) returned the questionnaire. Among the responders, 200 diabetologists and 99 general practitioners (GPs) recruited 3,297 patients; 2,003 of whom were always followed by the same physician and 1,294 of whom were seen by different physicians in the same structure on different occasions. Only 14% of the respondents used target FBG levels < or = 6.1 mmol/l, whereas 38% pursued values >7.8 mmol/l, with no statistically significant difference between diabetologists and GPs. The analysis of the relationship between FBG targets and metabolic control, restricted to those patients always seen by the same physician, showed a strong linear association, with mean HbA1c values of 7.0 +/- 1.6 for patients in the charge of physicians pursuing FBG levels < or = 6.1 mmol/l and 7.8 +/- 1.8 for those followed by physicians who used target values >7.8 mmol/l. After adjusting for patients' and physicians' characteristics, the risk of having HbA1c values > 7.0% was highly correlated with physicians' beliefs. Patients followed by different physicians in the same unit showed a risk of inadequate metabolic control similar to that of patients followed by physicians adopting a nonaggressive policy. CONCLUSIONS: Doctors adopt extremely heterogeneous target FBG levels in patients with type 2 diabetes, which in turn represent an important independent predictor of metabolic control. To improve patient outcomes, physicians-centered educational activities aimed at increasing the awareness of the potential benefits of a tight metabolic control in patients with type 2 diabetes are urgently needed.