Patients Receiving a Primary Unicompartmental Knee Replacement Have a Higher Risk of Revision but a Lower Risk of Mortality Than Predicted Had They Received a Total Knee Replacement: Data From the National Joint Registry for England,Wales, Northern Ireland,and the Isle of Man

BackgroundTo determine unicompartmental (UKR) and total knee replacement (TKR) revision rates, compare UKR revision rates with what they would have been had they received TKR instead, and assess subsequent re-revision and 90-day mortality rates.MethodsUsing National Joint Registry data, we estimated UKR and TKR revision and mortality rates. Flexible parametric survival modeling (FPM) was used to model failure in TKR and make estimates for UKR. Kaplan-Meier estimates were used to compare cumulative re-revision for revised UKRs and TKRs.ResultsTen-year UKR revision rates were 2.5 times higher than expected from TKR, equivalent to 70 excess revisions/1000 cases within 10 years (5861 excess revisions in this cohort). Revision rates were 2.5 times higher for the highest quartile volume UKR surgeons compared to the same quartile for TKR and 3.9 times higher for the lowest quartiles respectively. Re-revision rates of revised TKRs (10 years = 17.5%, 95% confidence interval [CI] 16.4-18.7) were similar to revised UKRs (15.2%, 95% CI 13.4-17.1) and higher than revision rates following primary TKR (3.3%, 95% CI 3.1-3.5). Ninety-day mortality rates were lower after UKR compared with TKR (0.08% vs 0.33%) and lower than predicted had UKR patients received a TKR (0.18%), equivalent to 1 fewer death per 1000 cases.ConclusionUKR revision rates were substantially higher than TKR even when demographics and caseload differences were accounted for; however, fewer deaths occur after UKR. This should be considered when forming treatment guidelines and commissioning services. Re-revision rates were similar between revised UKRs and TKRs, but considerably higher than for primary TKR, therefore UKR cannot be considered an intermediate procedure.     

Pig kidney xenotransplantation: Progress toward clinical trials

Pig organ xenotransplantation offers a solution to the shortage of deceased human organs for transplantation. The pathobiological response to a pig xenograft is complex, involving antibody, complement, coagulation, inflammatory, and cellular responses. To overcome these barriers, genetic manipulation of the organ‐source pigs has largely been directed to two major aims—(a) deletion of expression of the known carbohydrate xenoantigens against which humans have natural (preformed) antibodies, and (b) transgenic expression of human protective proteins, for example, complement‐ and coagulation‐regulatory proteins. Conventional (FDA‐approved) immunosuppressive therapy is unsuccessful in preventing an adaptive immune response to pig cells, but blockade of the CD40:CD154 costimulation pathway is successful. Survival of genetically engineered pig kidneys in immunosuppressed nonhuman primates can now be measured in months. Non‐immunological aspects, for example, pig renal function, a hypovolemia syndrome, and rapid growth of the pig kidney after transplantation, are briefly discussed. We suggest that patients on the wait‐list for a deceased human kidney graft who are unlikely to receive one due to long waiting times are those for whom kidney xenotransplantation might first be considered. The potential risk of infection, public attitudes to xenotransplantation, and ethical, regulatory, and financial aspects are briefly addressed.     

Granulomatosis with polyangiitis: clinical course and outcome of 60 patients from a single center in South India

Granulomatosis with polyangiitis (GPA) previously known as Wegener’s granulomatosis is one of the forms of idiopathic systemic vasculitis. There is very scanty data available on GPA in Asian and Indian population. We studied data of 60 patients from southern India, diagnosed with GPA to describe the physical characteristics, the treatment, and outcome. Patients who fulfilled any two of the four criteria proposed by the American College of Rheumatology, and those with clinical features of GPA with ANCA positivity and histopathological confirmation, were included in the study. Disease activity and damage were assessed by Birmingham Vasculitis Activity Score v. 3 (BVAS v. 3) and Vasculitis Damage Index (VDI), respectively. Relapses were defined as recurrence of GPA of sufficient severity to require treatment or increase in the dose of treatment on a patient who was previously stable. Out of 60 patients, initial BVAS evaluation showed that 57 (95%) patients had severe disease and 3 (5%) patients had limited disease where median BVAS was 21.5 (range 17–44). Follow-up BVAS evaluation for severe disease showed that 13 (22.8%) patients continued with severe disease of which 9 patients did not survive, 24 (42.3%) had remission, 11 (19.2%) had persistent disease, and 9 (15.7%) were lost to follow-up. The mean VDI score was 2.5 ± 2. Renal involvement was established in 42 (70%) patients. Upper and lower respiratory involvement was seen in 38 (63%) patients. Nervous system involvement was noted in the 15 (25%) patients. Articular manifestations were seen in 16 (27%) patients. Diverse clinical manifestation delay early diagnosis and treatment of this potentially treatable vasculitis. Focused approach could expedite early diagnosis and can reduce the mortality.     

SUNCT and SUNA: medical and surgical treatments

Cognitive deficits may contribute to falls in Parkinson’s disease (PD) and these deficits may be risk factors for falls. However, their association with falls has been generally studied in patients with continuous gait problems. There have been few studies in PD patients without postural instability. In addition, the effectiveness of various simple bedside cognitive tests in predicting falls has not been established. In this study, we investigated the effectiveness of three bedside cognitive tests in consecutive patients with PD without postural instability. Of the 119 patients, 39 experienced falls during the follow-up period. Of the bedside cognitive assessment methods examined, only the Montreal Cognitive Assessment (MoCA) score was significantly lower in the group of fallers than in the group of non-fallers. This result suggests that the MoCA is effective as a bedside test for evaluating the risk of falls.     

Feature integration in pattern perception

The human visual system is able to effortlessly integrate local features to form our rich perception of patterns, despite the fact that visual information is discretely sampled by the retina and cortex. By using a novel perturbation technique, we show that the mechanisms by which features are integrated into coherent percepts are scale-invariant and nonlinear (phase and contrast polarity independent). They appear to operate by assigning position labels or “place tags” to each feature. Specifically, in the first series of experiments, we show that the positional tolerance of these place tags in foveal, and peripheral vision is about half the separation of the features, suggesting that the neural mechanisms that bind features into forms are quite robust to topographical jitter. In the second series of experiment, we asked how many stimulus samples are required for pattern identification by human and ideal observers. In human foveal vision, only about half the features are needed for reliable pattern interpolation. In this regard, human vision is quite efficient (ratio of ideal to real ≈ 0.75). Peripheral vision, on the other hand is rather inefficient, requiring more features, suggesting that the stimulus may be relatively underrepresented at the stage of feature integration.     

Reassessing Medical Risk in Living Kidney Donors

The short- and long-term effects of unilateral nephrectomy on living donors have been important considerations for 60 years. Short-term risk is well established (0.03% mortality and <1% risk of major morbidity), but characterization of long-term risk is evolving. Relative to the general population, risk of mortality, ESRD, hypertension, proteinuria, and cardiovascular disease is comparable or lower. However, new studies comparing previous donors with equally healthy controls indicate increased risk of metabolic derangements (particularly involving calcium homeostasis), renal failure, and possibly, mortality. We discuss how these results should be interpreted and their influence on the practice of living donor kidney transplantation.