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Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXIII | Pages 43 - 43
1 May 2012
Crawford S Ward H Wills R
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We report decreased clinical VTE rates following increased use of mechanical prophylaxis in elective kip and knee arthroplasty. Usage of intermittent pneumatic compression (IPC) increased due to the increased availability of pump machinery. Timing of IPC use also changed with IPC used intraoperatively on the unoperated limb and for a longer period postoperatively Clinical VTE rates are assessed for two years prior to the change in practice (1140 procedures) and two years afterwards (1285 procedures). There was no other change in practice (chemical thromboprophylaxis, anesthetic technique, use of compression stockings, usage of tourniquet or usage of cement) or in patient profile.

Overall clinical VTE rates during admission dropped from 2.98% to 0.62% (p<0.0001). This decrease was seen in both hips 1.77% to 0.2% (p=0.029) and knees 3.97% to 0.89% (p=0.0002). There was a decrease in both pulmonary emboli 1.14% to 0.16% (p=0.0043) and symptomatic DVT 1.84% TO 0.47% (p=0.0023). There was no change in the rate of post discharge VTE events recorded 1.07% (p=0.57), either for DVT or PE (P=0.74 for each).

We conclude that IPC with non-sequential calf compression is effective in reducing the rates of clinical in-hospital VTE after elective hip and knee arthroplasty.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_II | Pages 313 - 314
1 May 2010
Wroblewski B Siney P Crawford S Purbach B Fleming P
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With an increasing number of primary total hip arthroplasties being carried out worldwide, and a lack or inadequate follow-up leading to delays in revision surgery, more complex problems including periprosthetic fracture have to be dealt with at revision surgery.

Unawareness, that clinical results do not reflect the mechanical state of the arthroplasty, together with strain shielding in the femur, progressive endosteal cavitation and stem migration may result in deterioration of the periprosthetic bone stock and femoral fracture.

Acute onset due to the fracture, severe symptoms and poor medical status of the patient usually demands immediate surgical intervention.

We have developed a modular cemented femoral component for revisions where deficiency of the proximal femur, or the femoral fracture, demands a variable extra-femoral portion of the stem. The shaft of the stem is 200mm or longer allowing the extra-medullary position to vary up to 15cm. It has a double polished taper

Between 1985 and 2007 the stem has been used in 79 revisions where there was a periprosthetic fracture. The mean age at surgery was 70 years (37–93) and the mean follow-up was 4 years (0–14 years 10 months). In 86% the primary surgery had been performed at another hospital. In 80% the fracture had united at one year. The main post-operative problem was dislocation in 10 cases between 7 days and 9 years after revision and was most common where the abductors were absent. 2 patients died in the post-operative period. Five hips have been re-revised, 3 for dislocation, 1 for Infection and 1 stem loosening.

Overall revision for periprosthetic fracture using this implant has given good results.

Although the results of this type of surgery are encouraging, this must not be considered as an alternative to regular follow-up and early intervention in cases where progressive loosening and deteriorating bone stock are likely to lead to a more demanding surgery.


Orthopaedic Proceedings
Vol. 87-B, Issue SUPP_III | Pages 301 - 301
1 Sep 2005
De Jong M Ray M Crawford S Crawford R
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Introduction and Aims: Reinfusion drains have been used to decrease the need for blood transfusion following total knee replacement. The aim of this study was to evaluate the degree of activation of platelets and leucocytes in both the blood that has been salvaged after total knee arthroplasty and the patients’ blood following reinfusion.

Method: A prospective series of 24 consecutive patients undergoing a primary total knee replacement in a case-control study were investigated. Post-operatively 12 patients received salvaged blood reinfusion and as a control, 12 patients underwent TKA with a standard drain. The reinfusion was initiated four hours after the operation. Blood samples were taken from all patients at three and five and a half to six hours post-operatively. A third sample was acquired in the treatment group from salvaged blood after reinfusion. Platelet, platelet-leucocyte and leucocyte activation markers were studied in both the drainage blood and the patients’ blood following reinfusion.

Results: Comparison between platelet, platelet-leucocyte and leucocyte activation markers in patients’ circulation prior to reinfusion compared to salvaged blood showed that almost all markers were significantly increased in salvaged blood. For example the platelet activation markers P-selectin (p< 0.01), Factor V (p< 0.01), CD40L (p< 0.01) and platelet derived microparticles (p< 0.01) were all significantly increased in the drainage blood. All studied platelet-leukocyte and leucocyte activation particles were also significantly increased. Following re-infusion of autologous salvaged blood there was no statistically measurable effect on activation markers of patients’ circulating platelets and leucocytes, but there was a slight drop in platelet count in the reinfused group compared to the control group. Levels of prothrombin fragment F 1+2 increased in the reinfused group compared to control indicating either activation of coagulation or simply the effect of addition of the high levels present in the salvage blood.

Conclusion: Blood from reinfusion drains showed a significant increase in activation of platelets and leukocytes indicating activation of coagulation. The reinfused blood did not lead to a difference in platelet and leukocyte activation but a decrease in platelets and an increase in fragment F1+2 suggests the possibility of activation of coagulation.


Orthopaedic Proceedings
Vol. 87-B, Issue SUPP_III | Pages 302 - 302
1 Sep 2005
Ray M Hatcher S Crawford S Crawford R McLoughlin L
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Introduction and Aims: Decreasing blood loss during total hip replacement (THR) remains a challenge for the orthopaedic surgeon. This study investigated the effects of the antifibrinolytics aprotinin and epsilon aminocaproic acid (EACA) against placebo on blood loss during primary total hip replacement. Their safety and mechanism of action was also investigated.

Method: Forty-five patients undergoing primary unilateral total hip arthroplasty were randomised to receive an infusion of either aprotinin, EACA, or placebo. Intra- and post-operative blood loss was measured, as was the rate of blood transfusion and changes in haemoglobin concentration. Clinical examination and duplex ultrasound was used in all patients to detect thrombotic events. All patients were assessed clinically six weeks post-op to detect adverse events. Platelet function was assessed using P-selectin, Platelet-monocyte aggregates (PMA) and factor V/Va levels. D-dimer activity was recorded as an indicator of fibrinolysis. Non-parametric statistical analysis was employed in the interpretation of results.

Results: There was no difference in demographics or pre-operative platelet function between the groups with the exception of the EACA group which had a lower pre-operative haemoglobin concentration. Intra-operative blood loss was significantly lower in the aprotinin group compared to placebo (p=0.01), similarly there was also a reduction in intra-operative blood loss in the EACA group but this did not reach statistical significance. Post-operative bleeding from closed suction drains was markedly reduced for both aprotinin (60%, p=< 0.01) and EACA (53%, p=< 0.001) compared to placebo. Markedly less haemoglobin was lost in drains in both antifibrinolytic groups, with aprotinin showing a 77% (p=< 0.0001) and EACA a 73% reduction (p=< 0.001) in post-operative haemoglobin loss. Despite this, no difference in the rate of blood transfusion was observed between groups. Total hip arthroplasty surgery led to the activation of platelets as evidenced by P-selectin, PMA and factor V/Va levels. However, platelet function was not affected by either aprotinin or EACA. Both antifibrinolytics showed a similar increase in D-dimer levels indicating a similar efficacy in inhibiting fibrinbolysis. There were no DVTs, PEs or infections recorded in the study, and no increase in adverse events was seen with the use of antifibrinolytics.

Conclusion: Infusion of either aprotinin or EACA reduces blood loss after primary THA. Both agents are equally effective and have a favourable safety profile. The two drugs inhibit fibrinolysis in a similar fashion, and this action appears to be independent of platelets.


The Journal of Bone & Joint Surgery British Volume
Vol. 85-B, Issue 5 | Pages 646 - 649
1 Jul 2003
Sterling GJ Crawford S Potter JH Koerbin G Crawford R

We prospectively investigated a consecutive series of ten patients undergoing a cemented primary total hip replacement (THR) for osteoarthritis in order to establish the elution characteristics of Simplex-tobramycin bone cement (Howmedica, Limerick, Ireland). Specimens of blood, urine and drainage fluid were collected for 72 hours postoperatively. Very high concentrations of tobramycin were found in the drainage fluid, with mean levels at one hour of 103 mg/l, which steadily declined to 15.1 mg/l after 48 hours. The mean serum tobramycin levels reached a peak of 0.94 mg/l at three hours and declined rapidly to 0.2 mg/l by 48 hours. The mean urinary tobramycin levels peaked at 57.8 mg/l at 12 hours with a rapid decline to 12.6 mg/l by 24 hours.

There was a direct correlation between the amount of tobramycin bone cement which was implanted and the amount of tobramycin systemically absorbed. Excellent local delivery was achieved with minimal systemic concentrations. Simplex-tobramycin bone cement is an efficient and safe method for the delivery of antibiotics after THR.


Orthopaedic Proceedings
Vol. 85-B, Issue SUPP_III | Pages 270 - 271
1 Mar 2003
Prasad S Bruce C Crawford S Higham MJ Garg J
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Introduction: It is commonly believed that markedly increased femoral anteversion is a primary abnormality and a consistent feature of hip dysplasia. It is also considered to be one of the main factors leading to redislocation. Apart from limited cadaveric studies, the true normal range of anteversion in infants is largely unknown. We measured femoral anteversion in infants using ultrasound. We are presenting our results measuring the femoral anteversion in both normal and DDH hips.

Methods and materials: Anteversion measurements are taken at the time of routine ultrasound screening for Developmental Dysplacia of Hip. This method was previously validated. We measured femoral anteversion in 76 infants with normal hips. We measured femoral ante-version in 27 hips with DDH. The mean femoral ante-version in normal babies is compared to the value in the babies with hip dysplasia using unpaired t-test.

Results: The mean value of femoral anteversion in normal babies in our series was 46.75° with 95% reference interval of 36.34° to 57.17°. The mean femoral anteversion in dysplastic hips was 50.39° with a 95% reference interval of 34.88° to 65.89°. The difference between normal and dysplastic hips was statistically significant (p value −0.0095 and 95% CI of 6.36° to 0.90°). This showed a small increase of femoral anteversion in the dysplastic hips.

Conclusion: We established reference ranges of femoral anteversion in normal and dysplastic hips. Our series showed only a small increase of femoral anteversion in the dysplastic hips. We showed that the markedly increased femoral anteversion was not a primary abnormality in hip dysplasia.