Design and field-of-view calibration of 114-660-GHz optics of the Earth observing system microwave limb sounder

This paper describes the optics design and field-of-view (FOV) calibration for five radiometers covering 114-660 GHz which share a common antenna in the Microwave Limb Sounder instrument on the National Aeronautics and Space Administration's Aura satellite. Details of near-field pattern measurements are presented. Estimated systematic scaling uncertainties (3/spl sigma/) on calibrated limb emissions, due to FOV calibration uncertainties, are below 0.4%. 3/spl sigma/ uncertainties in beamwidth and relative pointing of radiometer boresights are 0.006/spl deg/ and 0.003/spl deg/, respectively. The uncertainty in modeled instrument response, due to the scan dependence of FOV patterns, is less than /spl plusmn/0.24 K equivalent black-body temperature. Refinements to the calibration using in-flight data are presented.     

Uncemented total shoulder arthroplasty. A review

Clinicians have had much experience with uncemented humeral components. A press-fitted humeral component will usually remain stable in the absence of a glenoid component. From the information available, surgeons should not continue to use press-fitted humeral components for total shoulder arthroplasty. Tissue ingrowth humeral components offer promise; however, the reports to date have short or intermediate length followup, and radiographic results do not equal those of cemented components. Early clinical results with tissue ingrowth glenoid components are excellent; radiographically evident changes occur much less frequently than they do following cement fixation. However, their disadvantage is the possibility of accelerated polyethylene wear and subsequent metal-induced synovitis. As such, there are no clear cut indications for cement fixation versus tissue ingrowth fixation for the glenoid component other than those intuitively based on bone quality and quantity in the glenoid fossa. Accruing experience will help to define the indications better, but given the similarity of clinical outcomes to date, distinction between the options may be difficult.     

Revision total shoulder arthroplasty for the treatment of glenoid arthrosis

The development of painful glenoid arthrosis is the most common reason for reoperation after replacement of the humeral head. We performed twenty-two revision total shoulder arthroplasties, between 1983 and 1992, for the treatment of painful glenoid arthrosis in shoulders that had a prosthetic replacement of the humeral head. Eighteen shoulders (seventeen patients) were included in the study as their preoperative and operative records were complete and they had been followed for at least two years (mean, 5.5 years; range, 2.3 to 10.0 years). The indications for the hemiarthroplasty were trauma (ten shoulders), osteoarthrosis (four), rheumatoid arthritis (two), and osteonecrosis secondary to the use of steroids (two). The mean interval between the hemiarthroplasty and the total shoulder replacement was 4.4 years (range, 0.8 to 12.7 years). The mean score for pain in the shoulder decreased from 4.3 points before the revision to 2.2 points after it (p = 0.0001). The mean active abduction increased from 94 degrees before the revision to 124 degrees after it (p = 0.01), and the mean external rotation increased from 32 to 58 degrees (p = 0.007). Two shoulders needed another operation after the revision because of a late infection in one and particulate synovitis associated with instability in the other. With the numbers available for study, we did not detect a significant difference in pain relief and range of motion with respect to gender, diagnosis, subluxation, or the presence of periprosthetic radiolucency. Our findings indicate that most patients with painful glenoid arthrosis after a hemiarthroplasty have marked pain relief and improvement in motion after revision to a total shoulder replacement. However, seven of the eighteen shoulders that had this procedure had an unsatisfactory result due to a limited range of motion or the need for a subsequent operation. Therefore, long-term studies are necessary to evaluate the durability of total shoulder replacement in this group of patients.     

Status of total shoulder arthroplasty

Some patients with degenerative, rheumatoid, and traumatic diseases of the glenohumeral joint require treatment primarily to relieve pain. In the absence of complete knowledge of basic mechanical requirements, clinical trials with both constrained and resurfacing prosthesis were initiated. Three types of constrained prostheses were placed in 23 patients. Pain relief was satisfactory, but six reoperations were necessary and motion greater than 90 degrees was rarely achieved. Twenty-five prostheses that were used to replace the glenohumeral articulation, but were not stable by virtue of design, were implanted. Again, pain relief was excellent; mechanical problems were not present, and motion was almost always greater than 90 degrees. Achieving stability by capsular-muscle cuff repair has not been as great a problem as anticipated. These results suggest that more emphasis should be placed on repair of the glenohumeral stabilizing structures than on their replacement.