Mortality following primary total knee replacement in public hospitals in Hong Kong

INTRODUCTION

More than 2000 total knee replacements are performed each year in Hong Kong and more than 10 000 patients are on the waiting list. How safe is total knee replacement, however? The aims of the study were to review the mortality of primary total knee replacement in public hospitals in Hong Kong and to identify risk factors for mortality in a high-volume hospital.

METHODS

All primary total knee replacements performed in Hospital Authority hospitals and Yan Chai Hospital from October 2011 to September 2014 were reviewed. Case-control analysis was performed for risk factors of total all-cause mortality in total knee replacement at Yan Chai Hospital.

RESULTS

There were 6588 patients in Hospital Authority hospitals and 1184 in Yan Chai Hospital (1095 unilateral and 89 bilateral total knee replacement). The mean follow-up time of patients in Yan Chai Hospital was 12.8 months. The mortality at 30 days, 90 days and 1 year was 0%, 0.08%, 0.34% for Yan Chai Hospital; and 0.1%, 0.2%, 0.7% for Hospital Authority hospitals, respectively. For Yan Chai Hospital, the mean operation-to-death interval was 21 months (range, 1-35 months). The mean age at death was 78 years and main causes were malignancy (50%) and pneumonia (21%). Predictors of mortality included age at surgery, American Society of Anesthesiologists class 3, and preoperative range of motion. Hospital surgery volume, preoperative co-morbidities, and postoperative deep vein thrombosis were not significant factors.

CONCLUSIONS

Mortality after primary total knee replacement was low in public hospitals in Hong Kong. Patients of older age or poorer general well-being in terms of poor range of motion or American Society of Anesthesiologists class 3 should be in optimal health before surgery and counselled about the higher mortality rate. A citywide joint replacement registry may help monitor and analyse postoperative total knee replacement mortality specific to our locality.

Short duration and low suction pressure drain versus no drain following total knee replacement

PURPOSE

To compare the short-term outcome in patients with or without a drain (short duration and low suction pressure) following total knee replacement (TKR).

METHODS

A consecutive series of 106 women and 48 men (mean age, 69 years) underwent unilateral TKR. The first 77 patients used a low suction pressure (200 mm Hg) drain following TKR for 24 hours, and the next 77 patients used no drain.

RESULTS

The 2 groups were comparable in terms of preoperative characteristics, the proportion of patients with pharmacological prophylaxis for deep vein thrombosis, the tourniquet time, and mode of anaesthesia. The mean drain output in the drain group was 221 ml. The time to achieve straight-leg-raising was earlier in the drain group (3.1 vs. 4.2 days, p<0.001).

CONCLUSION

The use of a short duration, low suction pressure drain following TKR enabled an earlier return of quadriceps power, without increasing haemoglobin drop and transfusion rate.

Risk factors for periprosthetic joint infection in total knee arthroplasty

PURPOSE

To evaluate the incidence and risk factors of periprosthetic joint infection (PJI) in patients undergoing total knee arthroplasty (TKA) in a high-volume hospital.

METHODS

Records of 1133 primary TKAs were reviewed. Correlation between surgery volume and infection rate was determined. Risk factors for PJI were identified using case-control analysis of variables. TKAs performed between October 2012 and March 2013 without infection were used as controls.

RESULTS

Of 1133 TKAs, 8 (0.71%) PJI occurred. The organisms involved were Staphylococcus aureus (n=4), coagulase-negative staphylococci (n=2), Pseudomonas aeruginosa (n=1), and methicillin-resistant S aureus (n=1). In the 6-month period chosen as the control period, one (0.52%) out of 192 TKAs developed PJI. Hospital annual volume did not correlate with infection rate (p=0.766). Significant risk factors included young age, comorbidities such as diabetes, anaemia, thyroid disease, heart disease, lung disease, and long operating time. Six of the 8 patients with PJIs had at least one risk factor. However, the number of patients with infection was too small to have sufficient power.

CONCLUSION

Comorbidities are a risk factor for PJI. Perioperative optimisation of comorbidities and the use of antibiotic-loaded cement in patients with severe comorbidities should be considered.

Pulmonary embolism presenting as disseminated intravascular coagulation

We report an unusual case of disseminated intravascular coagulation. Occult pulmonary embolism is a recognised cause of disseminated intravascular coagulation. Unexplained shock should prompt the physician to search for a thrombotic cause such as pulmonary thromboembolism.

Depression in institutionalised older people with impaired vision

OBJECTIVES

For depression in institutionalised elders with visual impairment, there is a lack of information in the literature. A panel study was performed: (1) to determine the prevalence of depressive symptoms, and (2) to investigate the risk factors of depression.

METHOD

Residents of a nursing home for the aged blind were recruited. Measurements included: Geriatric Depression Scale (GDS), Snellen Eye Chart, age, duration of institutionalisation, duration of impaired vision, and functional ability.

RESULTS AND CONCLUSIONS

The proportion of participants who scored GDS> or =6/15 was 45.2%. The rate of depression among visually impaired nursing home residents is higher compared to other populations reported. The depressed participants had significantly shorter duration of institutionalisation (3.4 years vs 7.1 years, rank-sum, p=0.007) and lower functional ability (Barthel Index 60.7/100 vs 85.6/100, rank-sum, p=0.002) as compared to the non-depressed. No significant difference was found in age and length of impaired vision. A logistic regression model predicting depressive symptoms found that the duration of institutionalisation (odds ratio 0.75; 95% confidence interval 0.59-0.94), and functional ability (odds ratio 0.96; 95% confidence interval 0.92-0.99), were independently and inversely associated with depressive mood after controlling for age and duration of blindness. The effects of blindness and living in a long-term care institution were identified. Recommendations on screening and management of depression were provided.

Outcomes of critically ill elderly patients: is high-dependency care for geriatric patients worthwhile?

OBJECTIVES

To study the outcomes of elderly patients in a high-dependency care unit and to evaluate the costs and benefits of a geriatric high-dependency unit (GHDU).

DESIGN

Prospective data collection and analysis.

SETTING

Geriatric high-dependency unit.

PATIENTS

One hundred fifty patients > or =70 yrs of age who had been admitted to the GHDU over a 10-month period were investigated during their treatment and rehabilitation.

MEASUREMENT AND MAIN RESULTS

The patients' Acute Physiology and Chronic Health Evaluation (APACHE) II scores and Simplified Acute Physiology Scores (SAPS) were recorded. The APACHE II scores and SAPSs provided a close correlation with the patients' mortality (correlation coefficients were 0.97 and 0.92, respectively). The SAPS proved to have a better linear relationship with the elderly patients' mortality in comparison with APACHE II scores. Most of the elderly patients included in the study were suffering from multiple premorbid medical problems. Overall, the mortality rate up to 1 month after discharge from the hospital was 48%. For patients ranging in age from 70 to 84 yrs, the 1-month mortality was 39.6%; however, for patients > or =85 yrs of age, the 1-month mortality was 68.1%. The mortality ratio was 0.96 (for all patients), 0.88 (for those ages 70-84 yrs), and 1.05 (for those age 85 yrs and above). For patients with nil organ system failure, the mortality rate was 32%. For patients with one organ system failure, the mortality increased to 48%. For patients with two organ system failures, the mortality rate was 86%. Survival for patients with three or more organ system failures was unprecedented. Survivors and nonsurvivors were compared. Three poor-prognosis groups were identified: group 1, patients who had received preadmission cardiopulmonary resuscitation; group 2, patients with a recent history of malignant diseases; and group 3, patients who had been mechanically ventilated. All three groups had a significantly higher mortality than those without these factors (p<.05). Patients in the 85 yrs and above group had a significantly higher mortality rate than those in the 70- to 84-yr age group (p<.05). Patients with SAPS and APACHE II scores >20 and >30, respectively, had a poor prognosis. The geriatric outcome scoring system (GOSS) was used as the functional outcome test for the survivors. The GOSS has three components: activities of daily living, mobility status, and social condition. At 1 month after discharge, 66.7% of the survivors returned to their premorbid activities of daily living abilities, 79.5% maintained their mobility status, and 91.7% remained at the same social environment. No survivors deteriorated more than one grade in any of the three components measured by the GOSS. The severity-of-illness scores, percentage of mechanical ventilation utilization, mortality rate, length of GHDU stay, and total hospital stay were comparable with those of other intensive care units (ICUs). The cost of 1 GHDU bed-day was equivalent to 24% of 1 ICU bed-day.

CONCLUSION

The prognostic information that we gathered from an unselected group of critically ill elderly patients is useful. The GHDU achieved treatment results similar to those achieved by an ICU and is therefore seen as an innovative way of treating critically ill elderly patients. High-dependency care for the elderly patient is worthwhile.

Colchicine-induced myopathy and neuropathy

Myopathy and neuropathy that have been induced by colchicine have been described only occasionally, although colchicine is a widely used drug. We describe a case of colchicine-induced myopathy and neuropathy in an 84-year-old woman who had renal impairment. Results from a muscle biopsy showed characteristic vacuolar myopathy and autophagic vacuoles. The cessation of medication resulted in a marked improvement of myopathy.

Lymphocyte subpopulation reference ranges for monitoring human immunodeficiency virus-infected Chinese adults

Two hundred eight healthy human immunodeficiency virus (HIV) type 1- and HIV type 2-seronegative Chinese adults (78 males and 130 females; mean age, 32 years; age range, 18 to 71 years) were analyzed for lymphocyte subsets by a standardized and quality-controlled flow cytometric immunophenotyping technique. While the leukocyte differential values were comparable to those found in studies of Caucasians, the means, medians, and 95% reference ranges of lymphocyte subsets were very different. The 95% reference ranges in absolute counts per microliter of whole blood (percentage of lymphocytes) for CD3+, CD3+ CD4+, CD3+ CD8+, CD3- CD19+ (B), and CD3- with CD16+ and/or CD56+ (NK) cells were 672 to 2,368 (54.8 to 83.0%), 292 to 1,366 (23.1 to 51.0%), 240 to 1,028 (17.9 to 47.5%), 82 to 560 (5.1 to 20.8%), and 130 to 938 (7.1 to 38.0%), respectively. CD3+ CD4+ cells showed significant sex difference (for males, mean of 702 [34.8%] and standard deviation of 258 [7.5%]; for females, mean of 728 [37.3%] and standard deviation of 254 [7.4%]) as well as an increase with age of 42 (1.6%) per decade. Investigations of the NK cell population did not show similar findings. Classification of HIV disease, treatment, and prophylactic regimens based on studies which relied heavily on estimations of lymphocyte subsets alone should be used with special caution for Chinese patients. Provided that adequate quality control measures are taken to ensure comparability of data, we recommend that these ranges be used on a day-to-day basis in laboratories that have not yet established their own reference ranges.

Postpartum anaemia is not related to maternal iron status in the third trimester

OBJECTIVE

To determine whether the maternal haemoglobin and iron stores of non-anaemic mothers (haemoglobin > or = 10 g/dl) who developed postpartum anaemia were lower compared to mothers who did not develop postpartum anaemia.

STUDY DESIGN

A prospective study was conducted in a teaching hospital on 467 low-risk mothers recruited from the antenatal clinic over a 3-month period, who were given only low dose iron supplement and delivered in the same hospital. Blood was drawn at 28-30 weeks for the measurement of haemoglobin, mean cell volume, serum ferritin, serum iron and total iron binding capacity. These results were compared between mothers with a postpartum day 3 haemoglobin of > or = 10 g/dl and those < 10 g/dl. Statistical analysis was performed with parametric and non-parametric methods as appropriate.

RESULTS

Mothers with postpartum anaemia had a higher incidence of postpartum haemorrhage (19.6% vs. 3.9%, P < 0.001) as well as heavier mean intrapartum blood loss (444 ml vs. 304 ml, P < 0.001), but there was no difference in the haemoglobin, mean cell volume, serum ferritin, serum iron and total iron binding capacity.

CONCLUSIONS

In mothers without antenatal anaemia, the development of postpartum anaemia is not related to the maternal iron status in the third trimester.

Lipids, lipoproteins and other coronary risk factors in Chinese male survivors of myocardial infarction

OBJECTIVE

To assess the importance of an abnormal lipid profile as a risk factor in relation to non-biochemical risk factors, and to define the risk levels for lipid, lipoprotein and apolipoprotein in a Chinese population.

PATIENTS AND METHODS

Serum lipids, lipoproteins, apolipoproteins and other cardiovascular risk factors were studied in 89 Chinese men 3 months after acute myocardial infarction and 56 controls.

RESULTS

Cases had higher mean total cholesterol (TC), LDL- and VLDL-cholesterol, triglycerides and apolipoprotein B (Apo B), and lower mean HDL-cholesterol and apolipoprotein AI (Apo AI). Mean BMI was also higher, as was the prevalence of smokers and subjects with a history of hypertension. In univariate analysis, the odds ratios for TG > or = 1.6 mmol/l, LDL-cholesterol > or = 4.1 mmol/l, VLDL-cholesterol > or = 0.73 mmol/l, Apo B > or = 104 mg/dl were of the same order of magnitude as being a current smoker, having a BMI > or = 24.3 kg/m2, and a history of hypertension. High HDL-cholesterol (> or = 1.39 mmol/l) and Apo AI (> or = 139 mg/dl) were protective factors. The odds ratios for successively higher quartile values of cholesterol were not statistically significant. Multiple logistic regression identified smoking habit, history of hypertension, obesity, high Apo B and low Apo AI concentrations as independent risk factors for myocardial infarction.

CONCLUSIONS

In a Chinese population, low serum Apo AI and high Apo B are risk factors for myocardial infarction of a comparable magnitude to smoking, hypertension and obesity.

Territory-wide survey of hospital infection in Hong Kong

A territory-wide prevalence survey of hospital infection in 10 Hong Kong hospitals was carried out in January 1987 using a standard protocol. Out of 9848 patients included in the survey, 2542 (25.8%) had infection, of which 844 (8.6%) were acquired in hospital and 1746 (17.7%) in the community. Although in North American studies there are higher rates of hospital-acquired infection in tertiary-referral and university-affiliated hospitals than in community hospitals, this was not found to be the case in Hong Kong. Factors contributing to the high rate of hospital-acquired infection in Hong Kong include the proportion of high-risk patients, the frequency of inter-hospital transfers, the crowdedness of wards and the education level of staff. In Hong Kong, hospital-acquired infections are important in large, as well as in small, hospitals.

Detection of single copies of Epstein-Barr virus in paraffin wax sections by non-radioactive in situ hybridisation

A highly sensitive non-isotopic in situ hybridisation technique was developed for the localisation of Epstein-Barr virus (EBV) in paraffin wax embedded tissue sections. The method uses a repeated sequence of the EBV genome as a probe, labelled with the novel reporter molecule, digoxigenin. The method can identify individual copies of EBV by detection of both EBV DNA and highly localised RNA transcripts. A combination of careful proteolytic digestion of tissue sections, high temperature denaturation of probe and target DNA, and sensitive immunocytochemical detection are used to attain single copy sensitivity. The technique is quicker and simpler to perform than some other methods used for the identification of EBV, and provides simultaneous morphological information which cannot be obtained by methods using tissue extracts. This method permits the investigation of the role of EBV in neoplastic conditions of lymphoid and epithelial cells, and may prove valuable in determining the sites of latent virus in healthy subjects.