Age and sex differences in presentation of symptoms among patients with acute coronary disease: the REACT Trial. Rapid Early Action for Coronary Treatment.

BACKGROUND: There are few data on possible age and sex differences in presentation of symptoms for patients with acute coronary disease. OBJECTIVE: To investigate demographic differences in presentation of symptoms at the time of hospital presentation for acute myocardial infarction (AMI) and unstable angina. METHODS: The medical records of patients who presented with chest pain and who also had diagnoses of AMI (n = 889) or unstable angina (n = 893) on discharge from 43 hospitals were reviewed as part of data collection activities of the Rapid Early Action for Coronary Treatment trial based in 10 pair-matched communities throughout the USA. RESULTS: Dyspnea (49%), arm pain (46%), sweating (35%), and nausea (33%) were commonly reported by men and women of all ages in addition to the presenting complaint of chest pain. After we had controlled for various characteristics through regression modeling, older persons with AMI were significantly less likely than were younger persons to complain of arm pain and sweating, and men were significantly less likely to report vomiting than were women. Among persons with unstable angina, arm pain and sweating were reported significantly less often by elderly patients. Nausea and back, neck, and jaw pain were more common complaints of women. CONCLUSIONS: Results of this study suggest that there are differences between symptoms at presentation of men and women, and those in various age groups, hospitalized with acute coronary disease. Clinicians should be aware of these differences when diagnosing and managing patients suspected to have coronary heart disease.

Treatment of acute fractures with a collagen-calcium phosphate graft material. A randomized clinical trial.

A prospective, randomized clinical trial was conducted concurrently at eighteen medical centers in order to compare the safety and efficacy of two types of graft material for the treatment of fractures of long bones: autogenous bone graft obtained from the iliac crest, and a composite material composed of purified bovine collagen, a biphasic calcium-phosphate ceramic, and autogenous marrow. Two hundred and thirteen patients (249 fractures) were followed for a minimum of twenty-four months to monitor healing and the occurrence of complications. We observed no significant differences between the two treatment groups with respect to rates of union (p = 0.94, power = 88 per cent) or functional measures (use of analgesics, pain with activities of daily living, and impairment in activities of daily living; p > 0.10). The prevalence of complications did not differ between the treatment groups except for the rate of infection, which was higher in the patients who were managed with an autogenous graft. Twelve patients who were managed with a synthetic graft had a positive antibody titer to bovine collagen; seven of them agreed to have intradermal challenge with bovine collagen. One patient had a positive skin response to the challenge but had no complications with regard to healing of the fracture. We concluded that, for traumatic defects of long bones that necessitate grafting, use of the composite graft material appears to be justified on the grounds of safety, efficacy, and elimination of the increased operative time and risk involved in obtaining an autogenous graft from the iliac crest.

Cardiac arrest during hip arthroplasty with a cemented long-stem component. A report of seven cases.

Seven patients had a cardiac arrest during hip arthroplasty with a cemented long-stem femoral component. Four patients died in the operating room, and three patients were successfully resuscitated. When the three survivors were eventually discharged from the hospital, they had no known permanent cardiac, pulmonary, or neurological sequelae. Factors that were common to all of the patients were advanced age, osteoporotic bone, a previously undisturbed intramedullary canal, and use of a long-stem femoral component and several batches of methylmethacrylate. Hip arthroplasty with a long-stem femoral component is associated with substantial risk in these patients. Excessive pressurization of cement should be avoided, and invasive hemodynamic monitoring should be used when the described conditions are present.

The effect of periodontal bone loss on bite force discrimination.

This study compared bite force discrimination between 14 treated periodontal patients with significant bone resorption and 14 control subjects who were free of periodontal disease. Bite force was measured using a strain gauge scale which permitted subjects to visually monitor when their bite force equaled a preset resistance. A bite force of 500 gm was selected as the standard. Subjects were presented with a series of paired resistance settings, one at a time, the first of each pair being the standard and the second being the comparator setting of some predetermined different amount. This procedure was continued until the subject's difference limen (DL) value, the threshold of discrimination between two bite forces, was established. The periodontal patients required an average of 334 additional grams of resistance over the standard before they could detect a difference, whereas the control subjects required only 201 additional grams. These group means were significantly different (P less than 0.01). The results of this study suggest that the periodontal ligament provides sensory feedback relative to bite force discrimination.

Osteoconductive materials and their role as substitutes for autogenous bone grafts.

The term osteoconduction applies to a three-dimensional process that is observed when porous structures are implanted into or adjacent to bone. Capillaries, perivascular tissues, and osteoprogenitor cells migrate into porous spaces and incorporate the porous structure with newly formed bone. The observed process is characterized by an initial ingrowth of fibrovascular tissue that invades the porous structure followed by the later development of new bone applied directly within it. This article reviews observations of commonly used osteoconductive matrices to increase understanding of this process.

Bone cells and matrices in orthopedic tissue engineering.

The ability to harvest and manipulate osteogenic cells gives clinicians the opportunity to harness capacity of these cells for targeted regeneration and repair of skeletal tissues. Further opportunities to optimize use of cells exist in the ability to design specialized matrices that act as conductive scaffolds. Realization of the full potential of engineered matrix materials and cell-matrix composites can provide new solutions to many clinical problems in skeletal reconstruction.

The use of Mitek anchors to secure mesh in abdominal wall reconstruction.

Abdominal wall complications of TRAM flap breast reconstruction are well described. Synthetic mesh abdominal reinforcement is believed to decrease the incidence of these complications. An innovative technique with commonly available suture anchors has been used in a case of recurrent abdominal laxity after a TRAM flap. Osseous fixation of synthetic mesh with the Mitek GII suture anchor will undoubtedly be used more widely in abdominal wall reconstruction.

Failure of bipolar hemiarthroplasty: a retrospective review of 31 consecutive bipolar prostheses converted to total hip arthroplasty.

Bipolar hemiarthroplasty has been widely used for the treatment of femoral neck fractures in elderly patients. Outcome studies show excellent results with near preoperative ambulation and lasting, painless hip function. However, what has only recently been considered is that, in some cases, failure of bipolar hemiarthroplasty may be due to wear of the thin, ultra-high-molecular weight polyethylene (UHMWPE) insert between the inner and outer bearings of the prosthesis with subsequent generation of particulate debris, periprosthetic osteolysis, and stem loos ening. We reviewed 31 consecutive bipolar hemiarthroplasties converted to total hip arthroplasties by a single surgeon between 1986 and 1994. The average time to failure was 38 months. Fifty-six percent of the cases showed radiographic evidence of osteolysis around the stem. Radiographic migration of the bipolar head of more than 1 mm into the pelvis, suggestive of cartilage wear, occurred in 67% of the cases. Among the patients with radiographic osteolysis and a loose stem at the time of revision, 92% showed a characteristic histiocytic and giant cell reaction to polyethylene particles in tissue obtained during surgery. The UHMWPE liners from the retrieved outer shells showed an average wear rate of 0.7 mm per year. Recent studies comparing bipolar to unipolar hemiarthroplasty show little difference between the two with regard to morbidity, mortality, or functional outcome. In light of our findings, it might be prudent to reconsider the design and indications for bipolar hemiarthroplasty.

Effect of mouth opening on bite-force discrimination.

The purpose of this study was to determine whether different extents of mouth opening affect normal subjects' (N = 24; 12 women, 12 men) ability to discriminate differences in their interincisor bite force. Three mouth openings were selected including 50, 70, and 90 percent of maximum opening for each subject. Bite force was measured using a specially designed strain gauge scale which permitted subjects to monitor visually when their biting force equalled a preset resistance. Resistance forces of 500 and 1000 gm. were selected as standards. The procedure involved the use of a modified method of constant stimuli in which each subject was presented with a series of paired resistance settings, one at a time--the first resistance setting being the standard and the second resistance was the comparator. This paired-comparisons procedure was continued until the subjects' difference limen (DL) value (the threshold of discrimination between two forces) could be established. An analysis of variance yielded no significant differences in subjects' ability to discriminate bite force as a function of mouth opening.

Proper design of clinical trials for the assessment of bone graft substitutes.

To assess the effectiveness and safety of engineered bone graft substitutes proper, clinical trials will need to be performed. Although the randomized placebo controlled prospective clinical trial is the gold standard, clinical trials of this design are difficult to perform in the surgical setting. At this writing, several clinical trials evaluating bone graft materials have been performed, and much was learned toward improving the design of future studies. This article reviews alternatives to the placebo controlled randomized clinical trials in the surgical setting. The importance of long term surveillance is emphasized.

The impact of modern cement techniques on acetabular fixation in cemented total hip replacement.

A radiographic study was performed to assess acetabular fixation in 78 total hip replacements performed between 1971 and 1980. In 1979, the technique of acetabular component insertion was modified to include water-pik lavage, preservation of subchondral bone of the acetabulum during reaming, multiple fixation holes in the pubis ischium and ilium, and devices that improve pressurization of the cement into the cancellous bone surfaces. The impact of these techniques was studied. A cumulative radiolucency score was calculated for each acetabulum from 5-year follow-up radiographs, and the mean cup radiolucency scores for two chronologic groups were compared using the t-test for independent samples. No significant differences in patient age, weight, or sex, type of prosthesis, or approach used was found between groups. The acetabular components inserted between 1979 and 1980 had significantly lower cup radiolucency scores than those inserted between 1971 and 1978, at 5-year follow-up evaluation. Modern cement technique may be responsible for significantly enhanced durability of acetabular fixation in cemented total hip replacement.

Current understanding of osteoconduction in bone regeneration.

Bone tissue is osteoconductive. In particular, cancellous bone with its porous and highly interconnected trabecular architecture allows easy ingrowth of surrounding tissues. When placed in an osseous environment, living tissue for the host bed migrates into the cancellous structure, which results in new bone formation and incorporation of that structure. This is the process of osteoconduction. The mineral and collagenous components of bone are osteoconductive. Osteoconduction also is observed in fabricated materials that have porosity similar to that of bone structure. Corallin ceramics, hydroxyapatite beads, and combinations of hydroxyapatite and collagen all have osteoconductive properties, and porous metals and biodegradable polymers. Osteoconduction appears to be optimized in devices that mimic not only bone structure, but also bone chemistry. The incorporation of calcium salts and collagen by osteoconductive matrices leads to more complete ingrowth with new bone formation.

A clinical and radiographic analysis of loosening of total knee arthroplasty components using a bilateral model.

Patients undergoing bilateral, simultaneous total knee replacement provide a unique opportunity to study the role of operative techniques in the development of radiolucent lines because variables such as age, sex, weight, diagnosis, and bone quality are internally matched when the result on one side is compared with that of the other. This allows more conclusive examination of operative factors, such as component alignment, level of tibial bone resection, and cement handling. With this as the objective, the clinical and radiographic results of the first 50 bilateral total knee replacements performed by the senior author were studied. Postoperative alignment was found to influence significantly the incidence of tibial radiolucent lines. Use of cement to reconstruct defects in the proximal tibia resulting from preoperative deformity consistently led to the development of radiolucent lines in the area of the defect. There was also indirect evidence that failure to achieve an intimate microinterlock at the bone-cement interface may play a major role in the development of tibial radiolucent lines.

Bilabial compression force discrimination by human subjects.

This study examined and compared bilabial compression force difference limen (DL) values (the minimally perceivable difference between two compression forces) for a group of twenty normal-speaking female subjects (mean age, 25 years) under conditions with and without the teeth clenched. In addition, measures of maximum bilabial compression force under conditions with and without the teeth clenched were obtained. Mean DL values obtained against a standard of 100 gm were 36 gm for the clenched condition and 38 gm with no clenching. Discrimination performance under these two conditions was not significantly different (P greater than 0.05). Mean maximum bilabial compression force was 411 gm with the teeth clenched and 568 gm without clenching. This difference in performance was significant (P less than 0.01). This study provides initial normal data against which individuals with labial sensorimotor dysfunction can be compared.

High-dose DDAVP intranasal spray (Stimate) for the prevention and treatment of bleeding in patients with mild haemophilia A, mild or moderate type 1 von Willebrand disease and symptomatic carriers of haemophilia A.

An open-label multicentre trial was conducted to evaluate high-dose DDAVP (desmopressin acetate) intranasal spray (Stimate; 1.5 mg mL(-1)), for the control of bleeding in 333 patients with mild haemophilia A, mild or moderate type 1 von Willebrand disease, or symptomatic carriers of haemophilia A. Overall, 278 patients received 2170 doses of high-dose DDAVP intranasal spray (1.5 mg mL(-1)). Using study-defined guidelines, patients evaluated the efficacy of high-dose DDAVP intranasal spray (1.5 mg mL(-1)) as 'excellent' or 'good' in 743 (95%) of 784 bleeding episodes. It demonstrated 'excellent' results in 384 (93%) of 413 administrations for prophylaxis and in eight of eight uses prior to acute surgical or dental procedures. When used for the treatment of menorrhagia, the efficacy of high-dose DDAVP intranasal spray (1.5 mg mL(-1)) was rated as 'excellent' after 655 (92%) of 721 daily uses. Of 2170 doses of high-dose DDAVP intranasal spray (1.5 mg mL(-1)), 172 (8%) were associated with adverse events. A total of 272 adverse events were reported among 80 patients. Of these, 239 (88%) were mild or moderate in intensity and only one patient was removed from the study due to an adverse event. These results demonstrate the safety and efficacy of high-dose DDAVP intranasal spray (1.5 mg mL(-1)) for control of bleeding episodes in patients with mildly decreased levels of factor VIII, von Willebrand factor, or both.

Unipolar versus bipolar hemiarthroplasty for the treatment of femoral neck fractures in the elderly.

This paper presents the short term results of an ongoing prospective randomized trial comparing a cemented unipolar with a cemented bipolar hemiarthroplasty for the treatment of displaced femoral neck fractures in the elderly. Forty-seven patients with an average age of 77 years completed 6-month followup. Outcomes at 6 weeks, 3 months and 6 months were assessed by completion of a patient oriented hip outcome instrument and by functional tests of walking speed and endurance. No differences in the postoperative complication rates or lengths of hospitalization were seen between the two groups. Patients treated with a bipolar hemiarthroplasty had greater range of hip motion in rotation and abduction and had faster walking speeds. However, no differences in hip rating outcomes were found. These early results suggest that use of the less expensive unipolar prosthesis for hemiarthroplasty after femoral neck fracture may be justified in the elderly.

Bite force discrimination by individuals with complete dentures.

The purpose of this study was to determine whether differences existed in interincisor bite force discrimination between a group of subjects wearing complete dentures and a group of dentate individuals. It was hypothesized that biting force is monitored at least in part by the sensory mechanism within the PDL and that the absence of the PDL would result in reduced bite force discrimination. A specially designed strain gauge scale was constructed for the measurement of bite force. Bite force discrimination was assessed at three different standards including 500, 1000, and 3000 gm. Data analysis revealed that, overall, bite force discrimination was not significantly different for the two groups. However, at the lightest standard of 500 gm, the dentate group performed significantly better (p less than .05) than the denture wearers. It is concluded that the sensory system within the PDL plays a role in monitoring bite force discrimination.

Human bite force discrimination using specific maxillary and mandibular teeth.

The purpose of this study was to determine whether performance differences existed in subjects' self-generated bite force discrimination ability using maxillary and mandibular central incisors, canines, premolars and first molars. Two separate studies were conducted: (i) to assess whether performance differences existed in subjects' bite force discrimination ability using central incisors and premolars; (ii) to compare subjects' performance on bite force discrimination using central incisors, canines and first molars. Assessment of bite force was measured using a specially designed strain gauge scale allowing subjects to visually monitor when their biting force equalled a preset resistance. Resistance forces of 500, 1000 and 3000 g were selected as standards. Subjects were presented with a series of paired resistance settings, one at a time, the first of each pair being the standard and the second being the comparator setting of a predetermined amount. This paired-comparisons procedure was continued until the subjects' difference limen (DL) value (the threshold of discrimination between two forces) could be established. The first study revealed no significant (P greater than 0.05) overall difference in subjects' bite force discrimination ability relative to specific teeth. In contrast, in the second study a significant difference (P less than 0.05) was identified in subjects' performance relative to specific teeth; subjects' performed better using central incisors compared to first molars. In both studies, subjects' performance was significantly better (P less than 0.05) using the 500 g standard compared to the 3000 g standard in the first study, and compared to the 1000 g standard in the second study. No significant differences (P greater than 0.05) were observed between the performance of males and females in either study.