A randomised, controlled trial of two mobile-bearing total ankle replacements.

We describe the results of a randomised, prospective study of 200 ankle replacements carried out between March 2000 and July 2003 at a single centre to compare the Buechel-Pappas (BP) and the Scandinavian Total Ankle Replacement (STAR) implant with a minimum follow-up of 36 months. The two prostheses were similar in design consisting of three components with a meniscal polyethylene bearing which was highly congruent on its planar tibial surface and on its curved talar surface. However, the designs were markedly different with respect to the geometry of the articular surface of the talus and its overall shape. A total of 16 ankles (18%) was revised, of which 12 were from the BP group and four of the STAR group. The six-year survivorship of the BP design was 79% (95% confidence interval (CI) 63.4 to 88.5 and of the STAR 95% (95% CI 87.2 to 98.1). The difference did not reach statistical significance (p = 0.09). However, varus or valgus deformity before surgery did have a significant effect) (p = 0.02) on survivorship in both groups, with the likelihood of revision being directly proportional to the size of the angular deformity. Our findings support previous studies which suggested that total ankle replacement should be undertaken with extreme caution in the presence of marked varus or valgus deformity.

Impending fractures in giant cell tumours of the distal femur: incidence and outcome.

Giant cell tumours are rare bone tumours that are characteristically benign but locally aggressive, most frequently occurring in the distal femur with pathological fractures being common. This paper investigates relationships between tumour size and cortical breach on initial X-rays and subsequent treatment. The X-rays of 54 patients with distal femoral giant cell tumours were reviewed. The volumes of the tumour, distal femur and a ratio between the two parameters were estimated. The presence of a cortical breach, discrete fracture and Campanacci grade was recorded. X-rays revealed intact cortical rim in 20 patients (37%), cortical breach in 22 patients (41%) and discrete fracture in 12 patients (22%). There was a significant difference in the ratio of tumour volume to distal femoral volume between the discrete fracture group and the cortical breach group. No significant differences in rates of local recurrence were demonstrated. Extended curettage was effective for intact and cortical breach groups; however, patients in the fracture group often required radical treatment.

Chondroblastoma of bone: long-term results and functional outcome after intralesional curettage.

We undertook this retrospective study to determine the rate of recurrence and functional outcome after intralesional curettage for chondroblastoma of bone. The factors associated with aggressive behaviour of the tumour were also analysed. We reviewed 53 patients with histologically-proven chondroblastoma who were treated by intralesional curettage in our unit between 1974 and 2000. They were followed up for at least two years to a maximum of 27 years. Seven (13.2%) had a histologically-proven local recurrence. Three underwent a second intralesional curettage and had no further recurrence. Two had endoprosthetic replacement of the proximal humerus and two underwent below-knee amputation after aggressive local recurrence. One patient had the rare malignant metastatic chondroblastoma and eventually died. The mean Musculoskeletal Tumour Society functional score of the survivors was 94.2%. We conclude that meticulous intralesional curettage alone can achieve low rates of local recurrence and excellent long-term function.

Metachronous haemorrhagic epithelioid and spindle cell haemangioma of bone.

We present the case of a 7-year-old boy with a haemorrhagic and spindle cell haemangiomas of the ring finger. The lesions appeared in a metachronous fashion initially in the distal phalanx and 16 months later in the proximal phalanx. Radiography revealed expansile lytic lesions of the phalanges. Haemorrhagic epithelioid and spindle cell haemangioma is a benign condition which, due to its unusual morphology, can be confused with more aggressive or malignant endothelial neoplasms. This condition with its possible multifocal presentation should be considered when diagnosing vascular lesions of bone in order that appropriate treatment can be implemented.

Measurement by intracoronary ultrasound of in vivo arterial distensibility within atherosclerotic lesions.

Arterial distensibility is diminished by atherosclerosis. This process has not been well studied in the coronary arteries. The purpose of this study was to assess changes in coronary arterial distensibility in 4 groups of patients. Group I (n = 20) consisted of patients with normal vessels, group II (n = 40) with diseased undilated vessels, group III (n = 15) after successful percutaneous transluminal coronary angioplasty (PTCA), and Group IV (n = 20) after successful directional coronary atherectomy (DCA). Intracoronary ultrasound imaging was used to assess distensibility, plaque morphology and atherosclerotic burden (expressed as the percentage of total vessel cross-sectional area occupied by plaque: percent plaque area). Distensibility was defined as percent change in lumen area in a cardiac cycle. Group I (normal vessels) had a distensibility = 14 +/- 5%, which was significantly greater than that seen in group II (distensibility = 4 +/- 2%, p < 0.001). In undilated vessels, distensibility was related to the degree of atherosclerotic burden (r = 0.75). This relation was curvilinear with a marked decrease in distensibility when percent plaque area exceeded 30%. Distensibility in group III (after PTCA) was higher than in group II (10 +/- 3 vs 4 +/- 2%, p < 0.001) despite a larger plaque burden (percent plaque area of 56 +/- 12 vs 46 +/- 11%, p < 0.005). The distensibility in group IV (after DCA) was also higher than in group II (8 +/- 4 vs 4 +/- 2%, p < 0.001) despite a similar residual percent plaque area (49 +/- 13 vs 46 +/- 11%, p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanisms of angiographically successful directional coronary atherectomy: evaluation by intracoronary ultrasound and comparison with transluminal coronary angioplasty.

To assess the mechanisms of luminal improvement, 40 patients undergoing directional coronary atherectomy and a matched control group of 25 patients undergoing angioplasty were evaluated with intracoronary ultrasound imaging before and after intervention. Despite similar sized vessels, a similar angiographic severity of diameter stenosis (75 +/- 12% for the angioplasty group vs 69 +/- 15% for the atherectomy group, p = NS), and a similar plaque burden (percent plaque area) before intervention (84 +/- 5% in the angioplasty group vs 85 +/- 13% in the atherectomy group, p = NS), the residual plaque area after intervention was significantly smaller in the atherectomy group (54 +/- 14%) compared with the angioplasty group (65 +/- 13%, p = 0.002). Despite excellent angiographic results, significant residual plaque was noted after either successful intervention. Based on the absolute changes in lumen area, plaque area, and vessel area, improvement in the lumen area in the atherectomy group occurred as a result of plaque "compression" (48%), plaque removal (37%), and vessel expansion (15%). In the angioplasty group, plaque "compression" accounted for 94% of the improvement in lumen area, whereas vessel expansion contributed 6%. Thus "compression" of plaque remains the major mechanism of luminal improvement during atherectomy.

Intracoronary ultrasound imaging: correlation of plaque morphology with angiography, clinical syndrome and procedural results in patients undergoing coronary angioplasty.

OBJECTIVES: This study was designed to establish the relation between ultrasound-derived atheroma morphology and the clinical, procedural and angiographic features of patients presenting for coronary angioplasty. BACKGROUND: Intracoronary ultrasound imaging provides accurate dimensional information regarding arterial lumen and wall structures. Atheroma composition may also be assessed by ultrasound; however, only limited studies have been performed in patients. METHODS: In 65 patients a diagnostic ultrasound imaging catheter or a combination imaging-angioplasty balloon catheter was used during coronary angioplasty to image both the lesion and the vessel segment just proximal to it (reference segment). Ultrasound images were analyzed for lumen, total vessel and plaque areas and were classified into five morphologic subtypes (soft, fibrous, calcific, mixed plaque and concentric subintimal thickening). These data were compared with angiographic morphologic features, procedural results and clinical angina pattern (stable vs. unstable). RESULTS: Morphologic analysis of the ultrasound images obtained from the lesion correlated well with the clinical angina syndrome. Compared with patients with stable angina, patients with unstable angina had more soft lesions (74% vs. 41%), fewer calcified and mixed plaques (fibrotic, soft or calcific components in one or more combinations [25% vs. 59%]) and fewer intralesional calcium deposits (16% vs. 45%) (all p < 0.01). There was no correlation between ultrasound and angiographic lesion morphologic characteristics for either the reference segment or the lesion. Ultrasound demonstrated greater sensitivity than angiography for identifying unstable lesions (74% vs. 40%). Dimensional analysis demonstrated a large plaque burden in the reference segments (45 +/- 15% of total vessel area). Postangioplasty plaque burden was also high (62 +/- 9%). There was a significant, but only fair correlation between lumen area determined by angiography and ultrasound for both the reference segment (r = 0.70, p < 0.001) and the postangioplasty lesion (r = 0.63, p < 0.05). CONCLUSIONS: Morphologic plaque classification by ultrasound is closely correlated to clinical angina but has little relation to established angiographic morphologic characteristics. Intracoronary ultrasound imaging during angioplasty identifies a large residual plaque burden in both the reference segment and the lesion. In the future, determination of plaque composition by intracoronary ultrasound may be important in selecting or modifying interventional therapeutic options.

Diagnosis of circumferential dissection of the ascending aorta by transesophageal echocardiography.

A 28-year-old woman with Marfan's syndrome presented with chest pain; transesophageal echocardiography showed circumferential dissection of the ascending aorta. Both aortic angiography with digital subtraction and computed tomography scanning with contrast were negative for dissection. Circumferential dissection of the ascending aorta was confirmed by surgery at which time replacement of the aorta and aortic valve were performed. Transesophageal echocardiography may become the most practical and reliable procedure for the diagnosis of aortic dissection.

Imaging in the catheterization laboratory.

In the past decade, there has been dramatic growth in the number of catheterization procedures, with over 1.3 million performed in 1990. In the past year, several large studies have documented the clinical safety of nonionic contrast agents for performing angiography. These agents are much more expensive than conventional high-osmolarity ionic agents, and thus their widespread use continues to be controversial. Digital recording of angiographic images is now routinely available. Although useful for rapid review of images, digital processing for analysis of stenoses, ventriculography, and coronary flow has not been widely accepted. Several recent studies compared quantitative techniques with subjective analysis and found little advantage. Similarly, although flow can be determined, no practical clinical method has emerged. Over the past year, intracoronary ultrasound and angioscopy have made important advances. These adjunctive imaging techniques allow careful investigation of atheroma morphology and lumen geometry not available with routine angiography. Use of these imaging modalities will contribute greatly to the study of vascular disease in the catheterization laboratory.

Study of the influence of left bundle branch block on the signal-averaged electrocardiogram: a qualitative and quantitative analysis.

UNLABELLED: To study the influence of left bundle branch block (LBBB) on the signal-averaged electrocardiogram (SAECG), quantitative and qualitative analyses of SAECG parameters were undertaken in 48 patients with electrocardiographic evidence of intrinsic LBBB and in 39 patients with a "normal" surface QRS duration (less than 120 msec) who underwent right ventricular pacing-induced LBBB. We assumed pacing of the right ventricular apex to be a suitable model of this conduction defect. Sustained monomorphic ventricular tachycardia (SMVT) was inducible in 16 of 48 patients with intrinsic LBBB and in 23 of 39 patients with pacing-induced LBBB. Utilizing a filter setting of 25 to 250 Hz, late potentials were defined as a total filtered QRS duration greater than or equal to 120 msec, a root mean square voltage in the terminal 40 msec (RMS 40) of less than or equal to 25 microV, and the duration of signals less than 40 microV (LAS 40) of greater than or equal to 38 msec. Only RMS 40 and LAS 40 criteria were used in patients with LBBB. Prolongation of LAS 40 and fragmentation of signals in the terminal portion of the filtered QRS were characteristic of all patients with LBBB aberration. Of those patients with intrinsic LBBB, the mean total filtered QRS duration, RMS 40, and LAS 40 for inducible and noninducible patients were significantly different (170 +/- 28, 16 +/- 10, 55 +/- 24, and 153 +/- 18 msec, 25 +/- 10 microV, 33 +/- 16.9 msec; p = 0.04, 0.009, and 0.007, respectively). Noninducible patients with a normal QRS duration demonstrated a 60% decrement in the mean RMS 40 value during pacing-induced LBBB. These changes resulted in a 59% false positive incidence of late potentials during pacing-induced LBBB. This correlated with a similarly low mean RMS 40 value in patients with intrinsic LBBB and no inducible SMVT, hence giving rise to a false positive incidence of late potentials of 63%. Since "standard" RMS 40 and LAS 40 criteria resulted in low specificity and positive predictive value, new parameters were selected and analyzed. The combination of RMS 40 less than or equal to 17 microV plus LAS 40 greater than or equal to 55 msec yielded the best overall statistical result, with a sensitivity, specificity, and total predictive accuracy of 69%, 81%, and 77%, respectively. IN CONCLUSION: (1) A reduction of RMS 40, prolongation of LAS 40, and fragmentation of signals in the terminal portion of the filtered QRS are characteristics of LBBB.(ABSTRACT TRUNCATED AT 400 WORDS)