Wound infection in hip and knee arthroplasty

We have studied prospectively the outcome of wound discharge in patients after arthroplasty of the hip and knee. Over a period of 3.5 years 530 primary arthroplasties were carried out in one hospital. Postoperative wound infections developed in 82. At a mean follow-up of two years a comparison was made between these patients and 82 with healthy wounds, in terms of symptoms and signs of deep infection.

There was an incidence of 1.1% of early deep infection, within six weeks in all cases. The rate of ‘superficial’ infection was 17.3% in the hips, 10.5% in the knees and 14.3% in total. At a mean follow-up of 26 months, there were no significant differences between the patients with infected wounds and a matched group of patients with healthy wounds in terms of the ESR, level of C-reactive protein, white cell count and radiological scores, but clinical scores were significantly worse in the patients with infected knees (p < 0.05). The length of stay was also significantly longer in this group (mean 14.6 days in the healthy wound group, 19 days in the problem group; p < 0.005). There was, however, no convincing evidence that these wound infections led to deep infection and early revision in the early to medium follow-up period. A larger and longer prospective trial would be necessary to shed more light on this potential problem.

Wound infection in hip and knee arthroplasty

We have studied prospectively the outcome of wound discharge in patients after arthroplasty of the hip and knee. Over a period of 3.5 years 530 primary arthroplasties were carried out in one hospital. Postoperative wound infections developed in 82. At a mean follow-up of two years a comparison was made between these patients and 82 with healthy wounds, in terms of symptoms and signs of deep infection. There was an incidence of 1.1% of early deep infection, within six weeks in all cases. The rate of 'superficial' infection was 17.3% in the hips, 10.5% in the knees and 14.3% in total. At a mean follow-up of 26 months, there were no significant differences between the patients with infected wounds and a matched group of patients with healthy wounds in terms of the ESR, level of C-reactive protein, white cell count and radiological scores, but clinical scores were significantly worse in the patients with infected knees (p < 0.05). The length of stay was also significantly longer in this group (mean 14.6 days in the healthy wound group, 19 days in the problem group; p < 0.005). There was, however, no convincing evidence that these wound infections led to deep infection and early revision in the early to medium follow-up period. A larger and longer prospective trial would be necessary to shed more light on this potential problem.

The coagulation profile in hepatosplenic schistosomiasis

The biological activity of blood coagulation factors II, V, VII, VIII, IX, X, XI and XII, fibrinogen and prekallikrein was assessed in 15 healthy subjects and 60 patients with endemic Egyptian hepatosplenomegaly. The degree of liver disease was graded according to the Child-Pugh classification, the intensity of S. mansoni infection was monitored by determination of circulating schistosome immune complexes (CSIC) level using a monoclonal antibody and hemostasis activation was detected by measurement of hemostatic markers D-dimer and prothrombin fragment 1 + 2 (F1+2). Functional activity of antithrombin III, alpha2-antiplasmin and protein C as well as quantitative determination of plasma concentrations of alpha1-antitrypsin, C1 activator inhibitor and alpha2-macroglobulin were also carried out. The progressive deterioration of liver function which matched the severity of the disease and the intensity of schistosomal infection led to a reduction in anticoagulant proteins (decreases in antithrombin III and protein C) resulting in hypercoagulability and thrombin generation (increased F1+2) subsequently followed by consumption (prolongation of coagulation screening tests, thrombocytopenia, hypofibrinogenemia and decreased factor VIII resulting in hypocoagulability and secondary fibrinolysis (increased D-dimer and decreased alpha2-antiplasmin). A significant decline in fibrinogen and factors VII, XII and prekallikrein was detected in bleeders compared with ascitic patients. The decline in factor XII was closely related to CSIC high titers in all disease groups, but was not correlated to D-dimer or F1+2 concentrations. This suggests that circulating schistosome immune complexes may exert an inhibitory effect on contact factor XII which should be taken into account when considering the reasons for schistosomal coagulopathy and bleeding in hepatosplenic schistosomiasis.

Disseminated intravascular coagulation in endemic hepatosplenic schistosomiasis

Thrombin and plasmin generation were assessed in patients with endemic hepatosplenic schistomiasis (15 hepatosplenomegalic, 15 splenomegalic, 15 with advanced hepatic fibrosis and ascites and 15 hepatosplenic patients with hematemesis). Prolongation of prothrombin time, partial thromboplastin time and thrombin time, thrombocytopenia, hypofibrinogenemia, a decrease in antithrombin III and protein C and S levels and elevation in fibrinopeptide A, D-dimer and thrombin-antithrombin complex levels were detected in all groups. The deficit in hemostatic parameters was more pronounced with the advancement of the disease and was maximal in the hematemesis group. Our data demonstrate an increase in both thrombin and plasmin generation and indicate that low grade disseminated intravascular coagulation may occur in association with endemic Egyptian hepatosplenic schistosomiasis even in the steady state without overt bleeding.

Fibrinolysis and the bleeding tendency in patients with hepatosplenic schistosomiasis

Fifty seven patients with schistosomiasis of the liver and spleen in both the compensated and decompensated states and 15 non-bilharzial subjects were studied. Fibrinogen, plasminogen, fibrinogen/fibrin degradation products, alpha 2-macroglobulin, antithrombin III and Cl-activator concentrations were evaluated in an attempt to assess abnormalities at various stages of the disease. The results showed a progressive decrease in fibrinogen and plasminogen concentrations; fibrin degradation products showed a progressive increase as the disease progressed. Together with a falling platelet count, these data indicate the possible occurrence of disseminated intravascular coagulation with enhanced fibrinolysis which was most pronounced in those who vomited blood. Antithrombin III concentration showed a progressive decrease in parallel with the progress of the disease, possibly due to decreased synthesis or increased consumption, or both. Cl-activator concentration showed no significant change from that in normal controls at any stage of the disease. These findings provide further evidence that disseminated intravascular coagulation and enhanced fibrinolysis in the late stages of schistosomiasis may contribute to the haemorrhagic diathesis seen in the liver and spleen.