Do standards of care and early outcomes of periprosthetic fractures change during the COVID-19 pandemic? A multicentre study

BACKGROUND

Periprosthetic fractures (PPFs) are a growing matter for orthopaedic surgeons, and patients with PPFs may represent a frail target in the case of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The purpose of this study is to investigate whether hospital reorganisations during the most severe phase of the SARS-CoV-2 pandemic affected standards of care and early outcomes of patients treated for PPFs in Northern Italy.

MATERIALS AND METHODS

Data were retrieved from a multicentre retrospective orthopaedics and traumatology database, including 14 hospitals. The following parameters were studied: demographics, results of nasopharyngeal swabs, prevalence of coronavirus disease 2019 (COVID-19), comorbidities, general health status (EQ-5D-5L Score), frailty (Clinical Frailty Scale, CFS), pain (visual analogue scale, VAS), anaesthesiologic risk (American Society of Anaesthesiology Score, ASA Score), classification (unified classification system, UCS), type of operation and anaesthesia, in-hospital and early complications (Clavien-Dindo Classification, CDC), and length of stay (LOS). Data were analysed by means of descriptive statistics. Out of 1390 patients treated for any reason, 38 PPFs were included.

RESULTS

Median age was 81 years (range 70-96 years). Twenty-three patients (60.5%) were swabbed on admission, and two of them (5.3%) tested positive; in three patients (7.9%), the diagnosis of COVID-19 was established on a clinical and radiological basis. Two more patients tested positive post-operatively, and one of them died due to COVID-19. Thirty-three patients (86.8%) presented a proximal femoral PPF. Median ASA Score was 3 (range, 1-4), median VAS score on admission was 3 (range, 0-6), median CFS was 4 (range, 1-8), median EQ-5D-5L Score was 3 in each one of the categories (range, 1-5). Twenty-three patients (60.5%) developed post-operative complications, and median CDC grade was 3 (range, 1-5). The median LOS was 12.8 days (range 2-36 days), and 21 patients (55.3%) were discharged home.

CONCLUSIONS

The incidence of PPFs did not seem to change during the lockdown. Patients were mainly elderly with comorbidities, and complications were frequently recorded post-operatively. Despite the difficult period for the healthcare system, hospitals were able to provide effective conventional surgical treatments for PPFs, which were not negatively influenced by the reorganisation. Continued efforts are required to optimise the treatment of these frail patients in the period of the pandemic, minimising the risk of contamination, and to limit the incidence of PPFs in the future.

LEVEL OF EVIDENCE

IV.

Clinical Activities, Contaminations of Surgeons and Cooperation with Health Authorities in 14 Orthopedic Departments in North Italy during the Most Acute Phase of Covid-19 Pandemic

Background: From 10 March up until 3 May 2020 in Northern Italy, the SARS-CoV-2 spread was not contained; disaster triage was adopted. The aim of the present study is to assess the impact of the COVID-19-pandemic on the Orthopedic and Trauma departments, focusing on: hospital reorganization (flexibility, workload, prevalence of COVID-19/SARS-CoV-2, standards of care); effects on staff; subjective orthopedic perception of the pandemic. Material and Methods: Data regarding 1390 patients and 323 surgeons were retrieved from a retrospective multicentric database, involving 14 major hospitals. The subjective directors' viewpoints regarding the economic consequences, communication with the government, hospital administration and other departments were collected. Results: Surgical procedures dropped by 73%, compared to 2019, elective surgery was interrupted. Forty percent of patients were screened for SARS-CoV-2: 7% with positive results. Seven percent of the patients received medical therapy for COVID-19, and only 48% of these treated patients had positive swab tests. Eleven percent of surgeons developed COVID-19 and 6% were contaminated. Fourteen percent of the staff were redirected daily to COVID units. Communication with the Government was perceived as adequate, whilst communication with medical Authorities was considered barely sufficient. Conclusions: Activity reduction was mandatory; the screening of carriers did not seem to be reliable and urgent activities were performed with a shortage of workers and a slower workflow. A trauma network and dedicated in-hospital paths for COVID-19-patients were created. This experience provided evidence for coordinated responses in order to avoid the propagation of errors.

Early mortality in hip fracture patients admitted during first wave of the COVID-19 pandemic in Northern Italy: a multicentre study

BACKGROUND

Treatment of hip fractures during the coronavirus disease 2019 (COVID-19) pandemic has posed unique challenges for the management of COVID-19-infected patients and the maintenance of standards of care. The primary endpoint of this study is to compare the mortality rate at 1 month after surgery in symptomatic COVID-positive patients with that of asymptomatic patients. A secondary endpoint of the study is to evaluate, in the two groups of patients, mortality at 1 month on the basis of type of fracture and type of surgical treatment.

MATERIALS AND METHODS

For this retrospective multicentre study, we reviewed the medical records of patients hospitalised for proximal femur fracture at 14 hospitals in Northern Italy. Two groups were formed: COVID-19-positive patients (C+ group) presented symptoms, had a positive swab for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and received treatment for COVID-19; COVID-19-negative patients (C- group) were asymptomatic and tested negative for SARS-CoV-2. The two groups were compared for differences in time to surgery, survival rate and complications rate. The follow-up period was 1 month.

RESULTS

Of the 1390 patients admitted for acute care for any reason, 477 had a proximal femur fracture; 53 were C+ but only 12/53 were diagnosed as such at admission. The mean age was > 80 years, and the mean American Society of Anesthesiologists (ASA) score was 3 in both groups. There was no substantial difference in time to surgery (on average, 2.3 days for the C+ group and 2.8 for the C- group). As expected, a higher mortality rate was recorded for the C+ group but not associated with the type of hip fracture or treatment. No correlation was found between early treatment (< 48 h to surgery) and better outcome in the C+ group.

CONCLUSIONS

Hip fracture in COVID-19-positive patients accounted for 11% of the total. On average, the time to surgery was > 48 h, which reflects the difficulty of maintaining normal workflow during a medical emergency such as the present pandemic and notwithstanding the suspension of non-urgent procedures. Hip fracture was associated with a higher 30-day mortality rate in COVID-19-positive patients than in COVID-19-negative patients. This fact should be considered when communicating with patients and/or their family. Our data suggest no substantial difference in hip fracture management between patients with or without COVID-19 infection. In this sample, the COVID-19-positive patients were generally asymptomatic at admission; therefore, routine screening is recommended.

LEVEL OF EVIDENCE

Therapeutic study, level 4.

Markers of Hemostatic System Activation during Thromboprophylaxis with Recombinant Hirudin in Total Hip Replacement

Coagulation activation markers were studied in 148 patients undergoing total hip replacement under recombinant-hirudin (Desirudin, TMRevasc) prophylaxis with the aim of investigating the efficacy and safety of this anticoagulant compared with heparin in terms of biological effects on coagulation variables and bleeding. Hirudin (10, 15 or 20 mg s.c. b.i.d.) or unfractionated heparin (5000IU s.c. t.i.d.) was administered immediately before surgery and continued for 8-12 days. Activated partial thromboplastin time (aPTT), prothrombin activation fragment F1+2 (F1+2), thrombin-antithrombin III complexes (TAT) and D-dimer were measured at baseline and on postoperative days 1,3 and 6, immediately before the morning injection.

In comparison with baseline values, heparin had little effect on aPTT whereas the three hirudin doses prolonged aPTT significantly with no differences among the three doses. Moreover, there were no group differences in perioperative or cumulative blood loss or transfusion requirements. F1+2 fragment, TAT and D-dimer plasma levels were higher than at baseline during the entire postoperative period, with different trends (F1+2 increasing, TAT decreasing, D-dimer increasing, decreasing and then increasing again), but without significant differences among the four treatment groups. Our findings suggest that specific inhibition of thrombin seems a safe and efficacious mode of blocking thrombin activity after hip surgery although it does not prevent thrombin generation.

Coagulation Activation Markers in the Prediction of Venous Thrombosis after Elective Hip Surgery

Background. Despite prophylaxis, deep vein thrombosis (DVT) after hip surgery continues to occur frequently. Thus it would be helpful if before surgery patients at higher risk of DVT could be identified and more adequate prophylaxis given. As part of an international study on the prevention of DVT after total hip replacement, we investigated whether preoperative levels of three coagulation activation markers, prothrombin fragment F1+2 (F1+2), thrombin-antithrombin III complexes (TAT) and D-dimer, correlate with results of postoperative venography.

Methods. 159 patients undergoing total hip replacement were randomized to receive 10, 15 or 20 mg desirudin bid or 5000 IU unfractionated heparin tid immediately before surgery and then for 11 days, until bilateral venography was performed. Preoperative F1+2, TAT and D-dimer plasma levels were measured using ELISA procedures. As no difference among anticoagulant treatments or in the interaction between treatments and DVT was detected for any of the three variables, results are reported as pooled data.

Findings. The frequency of DVT was 18.8% in the low (0.75-1.33 nM) vs 65.7% in the high third of distribution (1.77-3.47 nM) of F1+2 (p ˂.001), 27.3% in the low (2.00-2.50 μg/1) vs 57% in the high third (5.10-61.00 μg/l) of TAT (p = .042), and 29.4% in the low (39-59 μg/1) vs 57.1% in the high third (129-651 μg/1) of D-dimer (p = .051).

Interpretation. Preoperative F1+2, TAT and D-dimer levels are associated with the risk of development of DVT after total hip replacement.

Diagnostic Value of Compression Ultrasonography and Fibrinogen-related Parameters for the Detection of Postoperative Deep Vein Thrombosis following Elective Hip Replacement: a Pilot Study

To determine their ability to diagnose postoperative deep vein thrombosis (DVT) D-dimer – by three methods – fibrinogen degradation products (FgDP) and fibrinogen levels were measured in 68 consecutive patients before elective surgery for hip replacement and on postoperative day 1, 3, 6, and 10. All patients received prophylaxis and underwent compression real-time B-mode ultrasonography (C-US) on postoperative day 5 and 9, and bilateral ascending venography on day 10. Twenty-two out of 68 patients developed asymptomatic postoperative DVT, which was limited to the calf veins in 14 and involved the proximal veins in 8 patients. C-US was negative in all patients on day 5. On day 9, C-US sensitivity and specificity for proximal DVT were 63% (95% confidence interval: 26%-90%) and 98% (89%-100%) respectively. Postoperative changes in the laboratory parameters evaluated were not different in patients with or without DVT until day 10. On day 10, mean D-dimer, FgDP and fibrinogen levels were significantly higher in patients with DVT than in those without DVT (p values between 0.006 and 0.032), but only D-dimer was higher with DVT involving two or more venous segments than with thrombosis involving one venous segment only (p <0.05). Stepwise logistic regression analysis identified D-dimer and fibrinogen on day 10 as predictors of postoperative DVT. In a receiver operator curve and after weighing for the coefficients generated by logistic regression analysis, the combination of a latex photometric immunoassay and of PT-derived fibrinogen yielded - at a cut-off value of 7.0 - a sensitivity of 100% (73%-100%) and a specificity of 58% (39%-75%) for DVT, with a negative predictive value of 100% (78%-100%), a positive predictive value of 52% (32%-71%) and an overall accuracy of 71% (55%-83%). These results suggest that two simple, fast and reproducible tests may permit the identification of patients at low risk of having postoperative DVT and that a combination of sensitive laboratory assays and of the highly specific C-US may select patients requiring anticoagulant treatment. Efficacy and cost-effectiveness of this approach should be evaluated in large clinical management studies.

Clinical Utility of Prothrombin Fragment 1+2, Thrombin Antithrombin III Complexes and D-dimer Measurements in the Diagnosis of Deep Vein Thrombosis following Total Hip Replacement

Background: Measurements of prothrombin fragment 1+2 (F1+2), thrombin antithrombin III complexes (TAT) and D-dimer plasma levels have been proposed as non-invasive screening tests to exclude postoperative deep venous thrombosis (DVT). We investigated the diagnostic efficacy of these coagulation activation markers to rule out postoperative DVT in patients undergoing hip surgery under antithrombotic prophylaxis. Methods: In this substudy of a randomized double-blind thrombosis prophylaxis trial comparing three doses of desirudin (10, 15 or 20 mg b.i.d.) with unfractionated heparin (5000 IU t.i.d.) we used ELISA procedures to measure F1+2, TAT and D-dimer in 159 patients undergoing total hip replacement at baseline (day 0) and on postoperative days 1, 3 and 6. Bilateral venography was performed in all cases 8-11 days after surgery. Results: For the F1+2 assay sensitivity ranged from 73 to 83% in the three postoperative days investigated, and negative predictive value (NPV) from 68 to 74%. For TAT and D-dimer sensitivity ranged from 71 to 73% and from 71 to 83% and NPV from 61 to 65% and from 61 to 74% respectively. Interpretation: In terms of sensitivity and NPV F1+2 and D-dimer are equivalent and are superior to TAT. However, their accuracy is too low to rule out the presence of DVT after hip surgery under antithrombotic prophylaxis.

Mid-term results of an uncemented femoral stem with modular neck options

We prospectively assessed the results of 239 primary total hip replacements performed using a conical stem combined with modular necks of different lengths and inclinations (Modulus System, Lima Corporate San Daniele Del Friuli, Udine, Italia) in 222 patients (50 men, 172 women), undergoing surgery between October 2001 and December 2006 and presenting with anatomical deformities of the proximal femur and/or acetabulum, including developmental dysplasia (DDH), ankylosis, and sequelae of osteotomies or fractures. Such conditions can make hip replacement problematic. The mean age at the time of surgery was 57.6 years (22 ÷ 83). No patients were lost to follow-up. 3 femoral components underwent revision. At a mean of 5 years follow-up the Harris Hip Score showed a significant improvement, increasing from 35 preoperatively to a mean of 96.6. Using Kaplan-Meier analysis the survival rate at 5 years was 98.28%. The Modulus stem showed good mid-term results in terms of survival, as well as clinical and radiographic outcome.

Modular stems in DDH

The Modulus (Lima-Lto) system has been created on the association of a conical stem and a modular neck in order to address the so called "difficult hip". Modularity can maximize the options for a correct reconstruction in a total hip replacement of the coxofemoral anatomy as well as biomechanics. Modulus should be used in CDH, primary hip arthritis, the sequelae of osteotomies and in each case in which we face a congenital or acquired hip deformity. The Modulus stem has been commonly utilised in association with the Delta cup (Lima-Lto) with the chance to use big diameter heads (32-36 mm) and ceramic on ceramic coupling. Modulus has been used in association with Delta cup since November 2002. 51 patients affected by CDH have been treated. Clinical and radiographic results can be considered very good. The average evaluation based on Merle D'Aubigné schedule is equal to 17.5 with a significant increase in the results with respect to the preoperatory score (with an average score equal to 10). In the light of the above, Modulus should be considered a valuable system to optimize the results of total hip replacement also in those more complex situations with a modified femoral morphology, allowing the restoration of a normal biomechanics in terms of off-set and anteversion with benefit in terms of stability and length of the implant as well as in terms of satisfaction of the patient as far as limb length and ROM are concerned. The association of Modulus with big diameter heads gives a higher guarantee in terms of duration of the implant and restoration of the functionality in young patients with a serious deformity and increased functional demands.

CGRP inhibits osteoprotegerin production in human osteoblast-like cells via cAMP/PKA-dependent pathway

The osteoprotegerin (OPG)/receptor activator of nuclear factor-kappaB ligand (RANKL)/receptor activator of nuclear factor-kappaB (RANK) system was evaluated as a potential target of CGRP anabolic activity on bone. Primary cultures of human osteoblast-like cells (hOB) express calcitonin receptor-like receptor (CLR) and receptor activity modifying protein 1, and, because CGRP stimulates cAMP (one of the modulators of OPG production in osteoblasts), it was investigated whether it affects OPG secretion and expression in hOB. CGRP treatment of hOB (10(-11) M-10(-7) M) dose-dependently inhibited OPG secretion with an EC(50) of 1.08 x 10(-10) M, and also decreased its expression. This action was blocked by the antagonist CGRP(8-37). Forskolin, a stimulator of cAMP production, and dibutyryl cAMP also reduced the production of OPG. CGRP (10(-8) M) enhanced protein kinase A (PKA) activity in hOB, and hOB exposure to the PKA inhibitor, H89 (2 x 10(-6) M), abolished the inhibitory effect of CGRP on OPG secretion. Conditioned media from CGRP-treated hOB increased the number of multinucleated tartrate-resistant acid phosphatase-positive cells and the secretion of cathepsin K in human peripheral blood mononuclear cells compared with the conditioned media of untreated hOB. These results show that the cAMP/PKA pathway is involved in the CGRP inhibition of OPG mRNA and protein secretion in hOB and that this effect favors osteoclastogenesis. CGRP could thus modulate the balance between osteoblast and osteoclast activity, participating in the fine tuning of all of the bone remodeling phases necessary for the subsequent anabolic effect.

Human osteoblast-like cell proliferation induced by calcitonin-related peptides involves PKC activity

The calcitonin peptides [calcitonin (CT), calcitonin gene-related peptide (CGRP), amylin] share many biological actions, including activity on bone cells. In the present study, CT (10(-11) to 10(-9) M) stimulated [(3)H]thymidine incorporation in primary cultures of human osteoblasts (hOB), as already demonstrated for CGRP and amylin. RT-PCR analysis showed that the calcitonin receptor and the calcitonin receptor-like receptor are both expressed in hOB. In these cells, CT (10(-10) M) and amylin (10(-9) M), in contrast to CGRP (10(-8) M), did not increase cAMP production. All three peptides stimulated protein kinase C (PKC) activity. To evaluate PKC involvement in hOB proliferation, cells were incubated with phorbol 12,13-dibutyrate, a stimulator of PKC activity; cell proliferation was increased in a dose-dependent manner (EC(50) = 3.4 x 10(-8) M). Staurosporine (10(-9) M), a PKC inhibitor, blocked phorbol 12,13-dibutyrate-induced PKC activity and cell proliferation. Inhibition of PKC by staurosporine also counteracted the stimulatory effect of CT, CGRP, and amylin on hOB proliferation. From these data, it is deduced that the activation of PKC is important for hOB proliferation and that it is involved in the anabolic effect of CT peptides on bone.

Intraoperative epidural anesthesia and postoperative analgesia with levobupivacaine for major orthopedic surgery: a double-blind, randomized comparison of racemic bupivacaine and ropivacaine

STUDY OBJECTIVE

To compare the onset time and duration of epidural anesthesia, and the quality of postoperative analgesia produced by levobupivacaine, racemic bupivacaine, and ropivacaine.

DESIGN

Prospective, randomized, double-blinded study.

SETTING

Inpatient anesthesia at a University Hospital.

PATIENTS

45 ASA physical status I, II, and III patients, undergoing elective total hip replacement.

INTERVENTIONS

After standard intravenous midazolam premedication and infusion of 500 mL of Ringer's acetate solution, patients were randomly allocated to receive epidural block with 0.5% levobupivacaine (n = 15), 0.5% bupivacaine (n = 15), or 0.5% ropivacaine (n = 15). Postoperatively, after pinprick sensation recovered at T(t), a patient-controlled epidural infusion was provided with 0.125% levobupivacaine, 0.125% bupivacaine, or 0.2% ropivacaine, respectively (baseline infusion rate 5 mL/hr; incremental bolus 2 mL, lockout time: 20 min). Intravenous ketoprofen was also available for rescue analgesia if required.

MEASUREMENTS AND MAIN RESULTS

The onset time of sensory block was 31 +/- 16 minutes with levobupivacaine, 25 +/- 19 minutes with bupivacaine, and 30 +/- 24 minutes with ropivacaine (p = 0.98), after a median (range) volume of 15 (10-18) mL in Group Levobupivacaine, 14 (10-18) mL in Group Bupivacaine, and 15 (10-18) mL in Group Ropivacaine (p = 0.85). Six patients in the ropivacaine group (40%) showed an intraoperative Bromage score <2 as compared with only three patients of Group Levobupivacaine (20%) and no patient of Group Bupivacaine (p = 0.02). Recovery of pinprick sensation at T(t) occurred after 214 +/- 61 minutes with levobupivacaine, 213 +/- 53 minutes with bupivacaine, and 233 +/- 34 minutes with ropivacaine (p = 0.26). A similar degree of pain relief was observed in the three groups without differences in local anesthetic consumption and need for rescue analgesia. Motor blockade progressively resolved without differences among the three groups.

CONCLUSIONS

Levobupivacaine 0.5% produces an epidural block of similar onset, quality, and duration as the one produced by the same volume of 0.5% bupivacaine, with a motor block deeper than that produced by 0.5% ropivacaine. When prolonging the block for the first 12 hours after surgery with a patient-controlled epidural infusion, 0.125% levobupivacaine provides adequate pain relief after major orthopedic surgery, with similar recovery of motor function as compared with 0.125% bupivacaine and 0.2% ropivacaine.

Five-year follow-up with a ceramic sandwich cup in total hip replacement

The results of the first 56 consecutive total hip replacements using a new cementless, sandwich (alumina-polyethylene-titanium) acetabular component are reported. From March 1994 to March 1995 we operated on 39 female and 17 male patients; their mean age was 62.8 years (range 32-85 years). The Harris Hip Score was used for clinical evaluation. X-rays were examined according to the DeLee and Charnley method. At an average follow up of 62.4 months, 51 patients had complete clinical and radiographic data. For them, we recorded a good clinical result (average HHS 90.6), and we could detect no acetabular radiolucencies on X-rays. At the 5-year follow-up the results of this ceramic acetabular cup are quite encouraging. As a matter of fact, although the clinical results are very similar to those reported by other authors with conventional ceramic-polyethylene coupling prosthesis, the absence of periacetabular radiolucency and socket migration could mean less debris formation, less acetabular wear and, consequently, a longer life of the implant.

Effects of calcitonin gene-related peptide and amylin on human osteoblast-like cells proliferation

Expression of mRNA for calcitonin gene-related peptide (CGRP) and CGRP receptor has been detected in osteoblasts indicating that CGRP could play a role in bone metabolism. In the present study, we evaluated the effect of CGRP on primary culture of human osteoblast-like cells proliferation. The peptide was able to stimulate [3H]thymidine incorporation in human osteoblast-like cells with a maximal effect at 10(-8) M. The proliferating activity of CGRP was not inhibited by the two antagonists, CGRP-(8-37) or amylin-(8-37), whereas amylin fragment antagonized the proliferating activity of amylin. In human osteoblast-like cells CGRP, but not amylin, was able to stimulate adenylyl cyclase activity and this effect was completely antagonized only by CGRP-(8-37) and not by amylin-(8-37). These data suggest that the CGRP induced stimulation of cAMP is not involved in the peptide proliferating effect in human osteoblast-like cells and that in this cell population there are receptor subtypes for CGRP, distinct from that of amylin.

An extra-articular cause of locking knee

We report an uncommon case of locking of the knee in a 23-year-old girl. It was due to an osteochondroma at the medial aspect of the proximal tibia.

Preoperative plasma levels of prothrombin fragment 1 + 2 correlate with the risk of venous thrombosis after elective hip replacement

Better preoperative identification of those patients at high risk of developing a deep vein thrombosis (DVT) after hip surgery could reduce the incidence of this postoperative complication, which still occurs despite prophylaxis. One hundred fifty-nine patients undergoing elective total hip replacement and given anticoagulant prophylaxis, were investigated, looking for the presence of a hypercoagulable state, that represents one element of Virchow's triad predisposing to DVT. Plasma levels of three markers of coagulation activation, namely prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin III complexes (TAT) and D-dimer were measured using ELISA procedures and were correlated with the results of the postoperative phlebography. A high correlation (p < 0.001) between the preoperative plasma levels of F1 + 2 and the risk of postoperative venous thromboembolism was detected. The performance of TAT and D-dimer levels in predicting DVT was lower. These findings support the hypothesis that preoperative measurement of coagulation activation markers might be useful in predicting DVT following a total hip replacement.

Clinical utility of prothrombin fragment 1+2, thrombin antithrombin III complexes and D-dimer measurements in the diagnosis of deep vein thrombosis following total hip replacement

BACKGROUND

Measurements of prothrombin fragment 1+2 (F1+2), thrombin antithrombin III complexes (TAT) and D-dimer plasma levels have been proposed as non-invasive screening tests to exclude postoperative deep venous thrombosis (DVT). We investigated the diagnostic efficacy of these coagulation activation markers to rule out postoperative DVT in patients undergoing hip surgery under antithrombotic prophylaxis.

METHODS

In this substudy of a randomized double-blind thrombosis prophylaxis trial comparing three doses of desirudin (10, 15 or 20 mg b.i.d.) with unfractionated heparin (5000 IU t.i.d.) we used ELISA procedures to measure F1+2, TAT and D-dimer in 159 patients undergoing total hip replacement at baseline (day 0) and on postoperative days 1, 3 and 6. Bilateral venography was performed in all cases 8-11 days after surgery.

RESULTS

For the F1+2 assay sensitivity ranged from 73 to 83% in the three postoperative days investigated, and negative predictive value (NPV) from 68 to 74%. For TAT and D-dimer sensitivity ranged from 71 to 73% and from 71 to 83% and NPV from 61 to 65% and from 61 to 74% respectively.

INTERPRETATION

In terms of sensitivity and NPV F1+2 and D-dimer are equivalent and are superior to TAT. However, their accuracy is too low to rule out the presence of DVT after hip surgery under antithrombotic prophylaxis.

Coagulation activation markers in the prediction of venous thrombosis after elective hip surgery

BACKGROUND

Despite prophylaxis, deep vein thrombosis (DVT) after hip surgery continues to occur frequently. Thus it would be helpful if before surgery patients at higher risk of DVT could be identified and more adequate prophylaxis given. As part of an international study on the prevention of DVT after total hip replacement, we investigated whether preoperative levels of three coagulation activation markers, prothrombin fragment F1 + 2 (F1 + 2), thrombin-antithrombin III complexes (TAT) and D-dimer, correlate with results of postoperative venography.

METHODS

159 patients undergoing total hip replacement were randomized to receive 10, 15 or 20 mg desirudin bid or 5000 IU unfractionated heparin tid immediately before surgery and then for 11 days, until bilateral venography was performed. Preoperative F1 + 2, TAT and D-dimer plasma levels were measured using ELISA procedures. As no difference among anticoagulant treatments or in the interaction between treatments and DVT was detected for any of the three variables, results are reported as pooled data.

FINDINGS

The frequency of DVT was 18.8% in the low (0.75-1.33 nM) vs 65.7% in the high third of distribution (1.77-3.47 nM) of F1 + 2 (p < .001), 27.3% in the low (2.00-2.50 micrograms/l) vs 57% in the high third (5.10-61.00 micrograms/l) of TAT (p = .042), and 29.4% in the low (39-59 micrograms/l) vs 57.1% in the high third (129-651 micrograms/l) of D-dimer (p = .051).

INTERPRETATION

Preoperative F1 + 2, TAT and D-dimer levels are associated with the risk of development of DVT after total hip replacement.

Effects of amylin on human osteoblast-like cells

Amylin has been reported to have bone-conserving effects. In the present study we evaluated the possible activity of the peptide on human osteoblast-like (hOB) cells in primary culture. Amylin between 10(-9) and 10(-6) M, dose-dependently stimulated cell proliferation with a maximal effect (200%) at 10(-6) M. In addition, amylin increased osteocalcin production when hOB cells were exposed to 1,25(OH)2D3 (10(-8)M) but there was a nonsignificant upward trend on alkaline phosphatase activity. The present results suggest that amylin could be included among the group of peptides endowed with osteogenic activity.

Markers of hemostatic system activation during thromboprophylaxis with recombinant hirudin in total hip replacement

Coagulation activation markers were studied in 148 patients undergoing total hip replacement under recombinant-hirudin (Desirudin, Revasc) prophylaxis with the aim of investigating the efficacy and safety of this anticoagulant compared with heparin in terms of biological effects on coagulation variables and bleeding. Hirudin (10, 15 or 20 mg s.c. b.i.d.) or unfractionated heparin (5000 IU s.c. t.i.d.) was administered immediately before surgery and continued for 8-12 days. Activated partial thromboplastin time (aPTT), prothrombin activation fragment F1 + 2 (F1 + 2), thrombin-antithrombin III complexes (TAT) and D-dimer were measured at baseline and on postoperative days 1,3 and 6, immediately before the morning injection. In comparison with baseline values, heparin had little effect on aPTT whereas the three hirudin doses prolonged aPTT significantly with no differences among the three doses. Moreover, there were no group differences in perioperative or cumulative blood loss or transfusion requirements. F1 + 2 fragment, TAT and D-dimer plasma levels were higher than at baseline during the entire postoperative period, with different trends (F1 + 2 increasing, TAT decreasing, D-dimer increasing, decreasing and then increasing again), but without significant differences among the four treatment groups. Our findings suggest that specific inhibition of thrombin seems a safe and efficacious mode of blocking thrombin activity after hip surgery although it does not prevent thrombin generation.

Diagnostic value of compression ultrasonography and fibrinogen-related parameters for the detection of postoperative deep vein thrombosis following elective hip replacement: a pilot study

To determine their ability to diagnose postoperative deep vein thrombosis (DVT) D-dimer - by three methods -, fibrinogen degradation products (FgDP) and fibrinogen levels were measured in 68 consecutive patients before elective surgery for hip replacement and on postoperative day 1, 3, 6, and 10. All patients received prophylaxis and underwent compression real-time B-mode ultrasonography (C-US) on postoperative day 5 and 9, and bilateral ascending venography on day 10. Twenty-two out of 68 patients developed asymptomatic postoperative DVT, which was limited to the calf veins in 14 and involved the proximal veins in 8 patients. C-US was negative in all patients on day 5. On day 9, C-US sensitivity and specificity for proximal DVT were 63% (95% confidence interval: 26%-90% and 98% (89%-100%) respectively. Postoperative changes in the laboratory parameters evaluated were not different in patients with or without DVT until day 10. On day 10, mean D-dimer, FgDP and fibrinogen levels were significantly higher in patients with DVT than in those without DVT (p values between 0.006 and 0.032), but only D-dimer was higher with DVT involving two or more venous segments than with thrombosis involving one venous segment only (p < 0.05). Stepwise logistic regression analysis identified D-dimer and fibrinogen on day 10 as predictors of postoperative DVT. In a receiver operator curve and after weighing for the coefficients generated by logistic regression analysis, the combination of a latex photometric immuno-assay and of PT-derived fibrinogen yielded-at a cut-off value of 7.0 a sensitivity of 100% (73%-100%) and a specificity of 58% (39%-75%) for DVT, with a negative predictive value of 100% (78%-100%), a positive predictive value of 52% (32%-71%) and an overall accuracy of 71% (55%-83%). These results suggest that two simple, fast and reproducible tests may permit the identification of patients at low risk of having postoperative DVT and that a combination of sensitive laboratory assays and of the highly specific C-US may select patients requiring anticoagulant treatment. Efficacy and cost-effectiveness of this approach should be evaluated in large clinical management studies.