The Effect of Cataract on Early Stage Glaucoma Detection Using Spatial and Temporal Contrast Sensitivity Tests

BACKGROUND

To investigate the effect of cataract on the ability of spatial and temporal contrast sensitivity tests used to detect early glaucoma.

METHODS

Twenty-seven glaucoma subjects with early cataract (mean age 60 ± 10.2 years) which constituted the test group were recruited together with twenty-seven controls (cataract only) matched for age and cataract type from a primary eye care setting. Contrast sensitivity to flickering gratings at 20 Hz and stationary gratings with and without glare, were measured for 0.5, 1.5 and 3 cycles per degree (cpd) in central vision. Perimetry and structural measurements with the Heidelberg Retinal Tomograph (HRT) were also performed.

RESULTS

After considering the effect of cataract, contrast sensitivity to stationary gratings was reduced in the test group compared with controls with a statistically significant mean difference of 0.2 log units independent of spatial frequency. The flicker test showed a significant difference between test and control group at 1.5 and 3 cpd (p = 0.019 and p = 0.011 respectively). The percentage of glaucoma patients who could not see the temporal modulation was much higher compared with their cataract only counterparts. A significant correlation was found between the reduction of contrast sensitivity caused by glare and the Glaucoma Probability Score (GPS) as measured with the HRT (p<0.005).

CONCLUSIONS

These findings indicate that both spatial and temporal contrast sensitivity tests are suitable for distinguishing between vision loss as a consequence of glaucoma and vision loss caused by cataract only. The correlation between glare factor and GPS suggests that there may be an increase in intraocular stray light in glaucoma.

Inferring community structure in healthcare forums. An empirical study

BACKGROUND

Detecting community structures in complex networks is a problem interesting to several domains. In healthcare, discovering communities may enhance the quality of web offerings for people with chronic diseases. Understanding the social dynamics and community attachments is key to predicting and influencing interaction and information flow to the right patients.

OBJECTIVES

The goal of the study is to empirically assess the extent to which we can infer meaningful community structures from implicit networks of peer interaction in online healthcare forums.

METHODS

We used datasets from five online diabetes forums to design networks based on peer-interactions. A quality function based on user interaction similarity was used to assess the quality of the discovered communities to complement existing homophily measures.

RESULTS

Results show that we can infer meaningful communities by observing forum interactions. Closely similar users tended to co-appear in the top communities, suggesting the discovered communities are intuitive. The number of years since diagnosis was a significant factor for cohesiveness in some diabetes communities.

CONCLUSION

Network analysis is a tool that can be useful in studying implicit networks that form in healthcare forums. Current analysis informs further work on predicting and influencing interaction, information flow and user interests that could be useful for personalizing medical social media.

Hip protectors: recommendations for conducting clinical trials--an international consensus statement (part II)

INTRODUCTION

While hip protectors are effective in some clinical trials, many, including all in community settings, have been unable to demonstrate effectiveness. This is due partly to differences in the design and analysis. The aim of this report is to develop recommendations for subsequent clinical research.

METHODS

In November of 2007, the International Hip Protector Research Group met to address barriers to the clinical effectiveness of hip protectors. This paper represents a consensus statement from the group on recommended methods for conducting future clinical trials of hip protectors.

RESULTS AND CONCLUSIONS

Consensus recommendations include the following: the use of a hip protector that has undergone adequate biomechanical testing, the use of sham hip protectors, the conduct of clinical trials in populations with annual hip fracture incidence of at least 3%, a run-in period with demonstration of adequate adherence, surveillance of falls and adherence, and the inclusion of economic analyses. Larger and more costly clinical trials are required to definitively investigate effectiveness of hip protectors.

Hip fracture discrimination by imaging ultrasound measurements of the calcaneus

Quantitative ultrasound measurements of the os calcis have recently been upgraded with imaging facilities. This has made measurements of a specific region of interest possible and improved the reproducibility of the method, but the diagnostic ability of imaging ultrasound has not yet been investigated thoroughly. We measured broadband ultrasound attenuation (BUA) and speed of sound (SOS) using imaging ultrasound as well as forearm bone mineral density (BMDarm) using dual-energy X-ray absorptiometry in three age-matched groups of women: (1) 25 women who were admitted to hospital due to a hip fracture; (2) 23 women who were admitted to hospital due to a fall without any fracture; and (3) 26 normal women. Furthermore, BMD of the hip (BMDhip) was measured in a subgroup of the hip fracture patients and those who had fallen. All measurements were performed during the index hospitalization in order to avoid any influence from bone loss due to immobilization after the fracture. We found a -0.48 SD deviation from expected age-matched values in BUA among the hip fracture patients, whereas the patients who had fallen showed a +0.16 SD deviance. For SOS, the figures were -0.70 SD for the hip fracture group and -0.06 SD for the patients who had fallen. For BMD of the arm we found values of -0.65 SD and +0.08 SD, respectively, whereas the figures for BMD of the hip were -0.66 SD and +0.13 SD, respectively. All parameters were significantly lower in the hip fracture group compared with the patients who had fallen. None of the parameters in the patients who had fallen deviated significantly from expected normal age-matched values. Neither BMD of the arm or BMD of the hip separated hip fracture patients and patients who had fallen significantly better than ultrasound (BUA or SOS) did. We conclude that imaging ultrasound (BUA or SOS) separates age-matched groups of hip fracture and non-fracture patients as well as BMD measurements do.

[Results after primary suture of rupture of the anterior cruciate ligament. A 4-5 year follow-up]

Forty patients (40 knees) with acute isolated or combined lesions of the anterior cruciate ligament treated by means of primary suture without reinforcement were followed-up 4-5 years postoperatively. In 75% of the patients, follow-up examination revealed clinical instability of the anterior cruciate ligament but only 25% of these had noteworthy subjective complaints (Lysholm knee score less than 83) and no significant difference was observed between the median knee scores for the group of patients with unstable knees and those with stable knees. On the other hand, however, a significant decrease in the level of activity (Tegner activity scale) was observed in patients with unstable knee joints as compared with patients with stable knees. These patients compensated for the defective stability by reducing the level of activity. Primary suture without plastic reinforcement cannot be recommended as the method of treatment of acute lesions of the anterior cruciate ligament because it does not provide long-term stability in the majority of patients.

Arthroscopy in diagnosis and treatment of hip disorders

Fourteen hip arthroscopies between January 1985 and May 1988 were reviewed. Included were ten women and four men with an age ranging from 12 to 76 years. Indications were avascular necrosis; loose bodies; osteoarthrosis, arthritis, or pain; and snapping hip. The diagnosis was verified in five cases, including arthroscopic removal of a loose body in one and resection of a plica bridging the space between the femoral head and acetabular roof in two patients. The diagnosis was rejected in three cases. In five cases, no pathologic changes were found. One arthroscopy was inconclusive because of a narrow field of vision in a dysplastic hip. No serious complications occurred. Hip arthroscopy is useful in diagnostics and surgical treatment of selected hip disorders. The rehabilitation time is short. Hip arthroscopy is, however, a technically demanding procedure.

Arthroscopic determination of patellofemoral malalignment

Patellofemoral alignment was determinant by arthroscopy according to the degree of knee flexion at which the lateral facet, the patellar ridge, and the medial facet of the patella gained contact with the femur. The intraarticular pressure was 75 mm Hg. In 17 patients with a normal patellofemoral joint, the lateral facet aligned at a mean knee flexion of 20 degrees, the patellar ridge at 35 degrees, and the medial facet at 50 degrees. Twelve patients with patellar subluxation showed no difference in the alignment of the lateral facet, but differed significantly with regard to alignment of both the ridge and the medial facet with contact at a mean flexion of 55 degrees and 85 degrees, respectively. The median measurements in 20 patients with idiopathic anterior knee pain did not deviate significantly from the normal material. However, the dispersion was increased significantly, with eight patients having increased measurements consistent with malalignment and three having decreased measurements below the lower limit of normal alignment. Patients with idiopathic anterior knee pain apparently can be reclassified according to the arthroscopically determined alignment, which may prove important in the treatment of these patients.

Treatment of clavicular fractures. Figure-of-eight bandage versus a simple sling

Seventy-nine out-patients with midclavicular fractures were included in a prospective, randomized trial comparing treatment with a figure-of-eight bandage and a simple sling. Sixty-one patients completed the study and were reevaluated clinically and radiographically after 3 months. We found that treatment with a simple sling caused less discomfort and perhaps fewer complications than with the figure-of-eight bandage. The functional and cosmetic results of the two methods of treatment were identical and alignment of the healed fractures was unchanged from the initial displacement.

Arthroscopy in acute knee injuries

The diagnostic value of arthroscopy was evaluated in 148 patients with acute hemarthrosis and/or instability of the knee. The treatment planned after clinical examination was compared with the treatment given after arthroscopy. Seventy-nine per cent of the patients had ligamentous injuries; 59 per cent of tears were combined with other injuries, and 71 per cent were complete ruptures. Stability testing under anesthesia was most inaccurate for the anterior cruciate ligament, with 13 per cent false positive and 30 per cent false negative results. The planned treatment was altered as a consequence of arthroscopy in 31 per cent of cases. Without arthroscopy, the preoperative diagnoses would have been seriously wrong in 15 per cent of the patients. Twenty per cent of total anterior cruciate ligament ruptures would have been overlooked.

Glued periosteal grafts in the knee

Periosteal grafting was performed in 4 patients with osteochondritis dissecans of the medial femoral condyle and 1 patient with osteonecrosis of the lateral femoral condyle following prednisone therapy. The lesions were drilled out deep into the cancellous bone. The periosteal graft was taken from the medial facet of the tibia and fixed to the excavated bony defect by the tissue glue Fibrinkleber Human Immuno (Tisseel). The patients were followed clinically, by arthroscopic examination and by radiography at 3, 6, and 12 months. After 1 year the borderline between the new and surrounding cartilage was hardly visible.

The accuracy of clinical examination of injury of the knee joint

This study is an analysis of the clinical examination of 118 consecutive patients with severe, acute injury of the knee joint, that is, with intra-articular effusion or with clinical suspicion of ligamentous instability. Both the clinical examination and the examination under anaesthesia for ligamentous instability involve a large number of falsely positive and falsely negative diagnoses. The greatest uncertainty is attached to the examination of the anterior cruciate ligament and menisci. The diagnostic specificity and the diagnostic sensitivity of the clinical examination of the anterior cruciate ligament are 0.75 and 0.62 respectively. The corresponding values for examinations under anaesthesia are 0.86 and 0.76 respectively. Two-thirds of the patients without intra-articular effusion, whose clinical examination gives rise to suspicion of ligamentous instability, however, have subclinical intra-articular haemorrhage and have as many cruciate and combined lesions as the whole series, viz. respectively 63 and 47 per cent. On the basis of this we conclude that arthroscopy should be carried out in all patients with a traumatic haemarthrosis or indication of ligamentous instability.

A review of the morphology of Perthes' disease

There are differences of opinion about the pathogenesis of Perthes' disease. All are agreed that it is due to ischaemia, but the cause of this and the size and number of infarctions are in dispute. Through the generosity of the contributors six whole femoral heads and core biopsies of five other cases have been studied radiographically and histologically. The findings ranged from an ischaemic arrest of ossification in the capital articular cartilage without infarction to multiple complete infarctions of the epiphysial bone. The ensuing reparative process contributes to the pathology, which is of a range to warrant grading or grouping.

Dislocated femoral neck fractures. A follow-up study of 98 cases treated by multiple AO (ASIF) cancellous bone screws

A series of 98 dislocated femoral neck fractures were treated by closed reduction and osteosynthesis with multiple AO (ASIF) cancellous bone screws. The patients were followed up for 2 years (or until death). The degree of dislocation did not have a statistically significant influence on the failure rate, which was, however, significantly correlated with poor reduction. Thirty-nine percent of the fractures were complicated by non-union or late segmental collapse. Forty-three of the patients participated in the 2 year follow-up examination. Of these patients, 38 had achieved excellent or good hip function. It was concluded that the reduction was the most important single factor in treatment of these factors.

A new thermoplastic casting material. A comparison between plaster of Paris and Hexelite

Plaster of Paris and Hexelite, a new thermoplastic bandage, were compared in the treatment of 183 patients with malleolar fractures, Colles' fractures or distortions of the finger joints. There were no statistically significant differences between the two types of bandages taking into account the strength of the bandage, the amount of skin damage and the patient's opinion of the bandage. Hexelite is seven times more expensive than plaster of Paris, and, in addition, is more difficult to handle. Hence its use has been discontinued.

Legg-Calvé-Perthes' disease. Morphological studies in two cases examined at necropsy

Specimens of femoral heads were studied at necropsy in two cases of Legg-Calve-Perthes' disease. One was that of a boy aged four years ten months who died from appendicitis; the other was from a boy aged six years who died from a malignant glioma. Both had been treated for one and a half years for Legg-Calve-Perthes' disease which was in a stage of repair at the time of death. The diseased femoral heads were moderately flattened but the surface cartilage was intact. Epiphysial bone and bone marrow were partly replaced by cartilage, fibrous tissue and granulation tissue, and new bone was being formed. Inflammatory reaction was inconspicuous. Enchondral bone formation was only slightly decreased, and the structure of the growth plate was undisturbed. There was no sign of systemic bone disease. In the first case the changes indicated that more than one episode of ischaemia had occurred, and an occlusion--probably from an old thrombus--was demonstrated in the posterior inferior retinacular artery of the femoral head. The last episode of ischaemia, furthermore, had caused infarction of part of the metaphysial bone. In both cases, the central area of the metaphysial bone of the affected femur contained fat, but there were few haemopoietic cells and it therefore looked pale. The findings are discussed in relation to previous work on the pathology in Legg-Calve-Perthes' disease, recent information on the vascularisation of the femoral head in children, and experimental and comparative animal studies.