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The Bone & Joint Journal
Vol. 102-B, Issue 9 | Pages 1158 - 1166
14 Sep 2020
Kaptein BL den Hollander P Thomassen B Fiocco M Nelissen RGHH

Aims

The primary objective of this study was to compare migration of the cemented ATTUNE fixed bearing cruciate retaining tibial component with the cemented Press-Fit Condylar (PFC)-sigma fixed bearing cruciate retaining tibial component. The secondary objectives included comparing clinical and radiological outcomes and Patient Reported Outcome Measures (PROMs).

Methods

A single blinded randomized, non-inferiority study was conducted including 74 patients. Radiostereometry examinations were made after weight bearing, but before hospital discharge, and at three, six, 12, and 24 months postoperatively. PROMS were collected preoperatively and at three, six, 12, and 24 months postoperatively. Radiographs for measuring radiolucencies were collected at two weeks and two years postoperatively.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXVII | Pages 244 - 244
1 Sep 2012
Thomassen B Pool L Van Der Flier R Stienstra R
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High volume infiltration with local anaesthetics (LIA) during total knee arthroplasty (TKA) for postoperative pain relief may be beneficial as compared to traditional methods. Retransfusion drains are used in TKA as alternative for allogeneic blood transfusions. When combining both modalities, recollected blood may contain large doses of local anaesthetics potentially leading to systemic toxicity during retransfusion. We investigated the safety of combining LIA and retransfusion of shed blood.

Twenty patients scheduled for primary TKA were included. During surgery two peri-articular injections with ropivacaine (total 375 mg) were given. Patients received an intraarticular retransfusion drain and a wound catheter for continuous infusion of ropivacaine (8 mg/hr) for 24 hours. Blood collected in the retransfusion device, was not retransfused but used for laboratory analyses. Patients’ blood samples were taken immediately after surgery, 3, 6 and 24 hours postoperatively. We predicted cumulative ropivacaine concentrations using patient and shed blood samples from 6 hours postoperatively. We modelled instant retransfusion by estimating the cumulative plasma concentrations. Our safety threshold was 0.15 mg/L unbound ropivacaine in a venous plasma sample, based on literature.

Total ropivacaine concentration was highest 24 hours postoperatively and unbound ropivacaine was maximal predominantly at 6 hours. Total ropivacaine concentrations ranged from 0.7 to 1.9 mg/L and unbound ropivacaine concentrations varied between 0.03 and 0.11 mg/L. At 6 hours median shed blood volume was 600 mL (range 303–869 mL). Interestingly was the difference (mean ± SD) in free fraction ropivacaine, in shed blood (68.8–4.6%) and in plasma (4.8 ± 1.1%).

Assuming retransfusion, an average 13 mg (range 6–18mg) of unbound ropivacaine would have been administered intravenously. The model used to estimate cumulative ropivacaine plasma levels showed that instant retransfusion potentially would have led to unbound venous plasma concentrations of above 0.15 mg/L.

Under the conditions in our study it is safe to use LIA in combination with continuous infusion of ropivacaine. However, in combination with the retransfusion of shed blood collected with the Bellovac ABT system this may lead to toxic levels. Before implementing the combination of both modalities formal testing is required.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_II | Pages 191 - 191
1 May 2011
Thomassen B Kate JT Draijer W Kort N Verburg A
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Introduction: The stress-response to surgery, known as a variety of well-characterized hormonal, metabolic, haematological and immunological changes, may be smaller in less invasive operations. Decreased blood loss, less soft tissue damage and inflammation leading to fast recovery are arguments used in promoting minimal invasive surgery (MIS).

Purpose: Does MIS TKR with the subvastus approach lead to less inflammation and muscle damage than conventional TKR with the medial parapatellar approach?

Material and Methods: Inflammation parameters (IL-6, IL-8 and IL-10, and CRP), muscle damage parameters (myoglobin, CK) and Hb values were determined preoperative and at 5 moments postoperative in 41 patients. Twenty patients operated through a MIS subvastus approach were compared to 21 patients with the standard medial parapatellair approach.

Results: Average age in was 69.2 yrs in conventional TKR (contr) versus 68.9 yrs in MIS. The Hb levels were 13.9 g/dl preoperative and decreased to 10.8 g/dl (contr) and 11.6 g/dl (MIS) 72 hours postoperative.

The mean IL-6 concentration increased from 6.8 (contr) vs 1.3 (MIS) pg/ml to 68.8 (contr) vs 45.1 (MIS) pg/ml 6 hours postoperative. The mean myoglobin concentration increased in TKP group from 47.7 ug/l pre-operative to 90.1 ug/l 6 hours postoperative, the values for MIS were 27.8 μg/l preoperative and 202.3 ug/l 6 hours postoperative, with significant differences at 2, 4, 6 hrs and day 1 post-operative.

Conclusion: Haemoglobin levels show no significant differences between conventional and MIS approach. Inflammation parameters were not significant different between the two groups. Myoglobin was the only muscle damage parameter with significant differences on several time points between both approaches. This may be explained by the used forces on surrounded tissues. The retractors are necessary to visualise the knee joint in MIS. These results show a trend towards more muscle damage compared to conventional TKR.