Session 15:
Poster med foredrag B
Onsdag 21. oktober
11:00 – 12:00
Lokale: Stockholm / Copenhagen
Chairmen: Søren Overgaard / Casper Foldager
151. No effect on tissue oxygenation at the ankle level after sciatic and saphenous nerve block
Ane Linde, Thomas Fichtner Bendtsen, Niels Christian Jensen, Kristian Kibak Nielsen, Frank Linde
Foot and ankle section, department of orthopaedics, Aarhus University Hospital; Department of Anaestesiology, Aarhus University Hospital
Background: Wound healing complications is a
significant problem after major foot and
ankle surgery. A frequency of more than
30% wound healing complications is
reported after total ankle replacement.
The frequency has apparently not
changed over the years despite strict
selection of patients and interventions in
order to reduce wound healing
complications. Therefore other
components of clinical practice are
examined for possible negative effect on
wound healing.
A possible contributory factor to
reduction of oxygen tension and thereby
negative effect on wound healing
frequency could be peripheral nerve
blocks.
Purpose / Aim of Study: The purpose was to detect any
influence of sciatic and saphenous
nerve block on tissue oxygenation at
the ankle level.
Materials and Methods: 20 patients scheduled for major foot
surgery had a sciatic and saphenous
nerve block prior to surgery.
Transcutaneous oxygen tension (tcpO2)
was measured before and after the
nerve block and after surgery. TcpO2
was measured at the ankle level and at
the thigh of both legs. The TCM400
Transcutaneous pO2 Monitoring System
(Radiometer, Copenhagen) was used
for all measurements.
Findings / Results: The median tcpO2 at the ankle level was
63 mmHg (IQR 53-66 mmHg) before and
60 mmHg (IQR 54-66 mmHg) after the
nerve block (p>0,05, Wilcoxon sign test).
No significant changes occurred
in the ipsilateral thigh or the contralateral
leg.
Generally, a small increase of TcpO2
was observed both in the operated leg
and the non-operated leg the first few
postoperative hours. However, one
patient had a marked reduction at the
ankle level in tcpO2 from 66 mmHg to 45
mmHg after the nerve block has been
applied.
Conclusions: Sciatic and saphenous nerve blocks
have generally no influence on the
tissue oxygenation at the ankle level
measured by transcutaneous oxygen
tension.
152. Can MRI predict the tissue quality of a meniscus tear?
Ahmad Siar Barat, Trine Torfing, Uffe Christiansen Jørgensen
Orthopedicsurgery and traumatology, Odense University Hospital; Radiology, Odense University Hospital
Background: Studies suggest that arthroscopic treatment of
degenerative meniscus tears in middle-aged and
elderly patients have a small effect, but not more
than supervised physical exercise. The question is
however, can MRI predict if a meniscus tear is
degenerative or not?
Purpose / Aim of Study: The objective of this study was to investigate the
correlation between meniscus tissue quality
(degenerative/non-degenerative) assessed on MRI
and during arthroscopy, in order to predict
degenerative meniscus tears by MRI.
Materials and Methods: 51 menisci from 50 patients (31 males, 19 females,
mean age 41.2 years), who underwent arthroscopic
meniscus surgery due to clinical signs of meniscus
tear, were included in order to describe the meniscus
tissue quality (degenerative/non-
degenerative/combination of both/undetermined)
arthroscopically and on MRI. All surgeries were
performed or supervised by a senior surgeon in
knee arthroscopy. The tissue quality of the torn
meniscus was classified as hard or soft at resection.
MRI was analyzed by a senior musculoskeletal
radiologist according to a validated MRI score.
Findings / Results: 15 menisci were rated non-degenerative and 17
menisci were rated degenerative both arthroscopic
and on MRI. (p=0.003, Fisher’s exact test). This
suggests a statistically significant relationship
between meniscus tissue quality rated arthroscopic
and meniscus tissue quality rated on MRI. Cramer’s
V was calculated to V=0.38 indicating a medium to
large effect size.
Conclusions: Our results suggest a statistically significant
relationship between meniscus tissue quality rated
arthroscopically and on MRI in patients with a
meniscus tear. Degenerative and non-degenerative
tears could not be predicted in all cases by MRI. The
predictive effect was medium to large.
153. Preoperative Oral Anticoagulants in Fast-track Hip and Knee Arthroplasty, Practice and Outcomes
Christoffer C Jørgensen, Kehlet Henrik
Section for Surgical Pathophysiology & The Lundbeck Foundation Centre for Fast-Track Hip and Knee Re, Rigshospitalet
Background: Perioperative management of oral
anticoagulants(OAC) is an increasing
challenge in major joint arthroplasty. Current
guidelines are complex and the benefit of
preoperative bridging in patients with
preoperative OAC treatment vs. potential
increased risk of bleeding is uncertain.
Purpose / Aim of Study: Investigation of management of OAC and
adherence to local and Danish Society of
Thrombosis and Hemostasis guidelines,
postoperative symptomatic thromboembolic
(TE), venous thromboembolic (VTE) and
major bleeding events.
Materials and Methods: Descriptive cohort study in THA and TKA,
prospective data on comorbidity and
dispensed prescriptions on OAC 6 months
prior to surgery. Information on perioperative
management of OAC, cause of length of
hospital stay (LOS) >4 days, and 30-days
readmissions from the Danish National
Patient Registry and medical records.
Findings / Results: Of 13775 procedures, 717(5.2%) had
OAC (649 Vitamin-K (Vit-K) antagonists/
68 new oral anticoagulants (NOAC)) of
which 78% were due to atrial flutter. Of
Vit-K, 66% received pre and
postoperative heparinbridging while 33%
paused preoperatively and were bridged
postoperatively. Local and national
guidelines were followed in 75% and
50% of OAC-patients respectively. There
were 5 (0.8%) TE in Vit-K (p<0.05) vs 22
(0.2%) in non-OAC patients. No TE
occurred in NOAC patients. We found no
difference in VTE between OAC and
non-OAC-patients (0.4 vs 0.5%). There
were 11 (1.5%) vs. 76 (0.5%) major
bleedings in OAC vs non-OAC patients
(p<0.05), 7 (1.6%) were in bridged Vit-K
and 3 (4%) in NOAC (p<0.05 vs non-
OAC).
Conclusions: National guidelines for OAC management are
not routinely used in clinical practice. There
was no difference in VTE, but increased risk
of TE and major bleeding with OAC,
especially in bridged Vit-K and NOAC
patients.
154. The influence of infecting microorganisms on outcome after infectious revision knee arthroplasty. A two year nationwide study
Martin Lindberg-Larsen, Frederik Taylor Pitter, Marianne Voldstedlund, Henrik Schrøder, Jens Bagger
Department of Orthopaedic Surgery, Bispebjerg Hospital; Section of Surgical Pathophysiology, Rigshospitalet; Department of Infectious Disease Epidemiology , Statens Serum Institut; Department of Othopaedic Surgery, Næstved Hospital
Background: The initial surgical treatment of the
infected knee arthroplasty is in most
cases a partial revision (surgical
debridement and exchange of tibial
insert) or a revision to spacer
procedure. Impact of the ethiological
agent on outcome is unknown.
Purpose / Aim of Study: To describe the distribution of
microorganisms causing primary
infection and influence on outcome
after revision surgery, measured as
re-infection or death.
Materials and Methods: 105 partial revisions and 218 revision-
to-spacer procedures were
registered in the Danish Knee
Arthroplasty Register (DKR) from
July 1 2011 to June 30 2013. Re-
infections causing re-revision (follow-
up=396 days) and 90 days mortality
were obtained from the Danish
National Patient Register and DKR.
Microbiology data was obtained from
the Danish Microbiology Database. 7
cases without microbiology data were
excluded.
Findings / Results: In 66(20.4%) cases cultures were
negative and in 12(3.3%) cases 1/5
intraoperative biopsies were culture
positive and thus considered
contaminated. S.aureus infections
were most common (n= 67;28%) and
associated with 13.4% re-infections,
6.0% mortality and 2(0.8%) cases of
methicillin resistance (MRSA).
S.epidermidis was found in 46
(19.2%) cases with 8.7% re-
infections and no deaths. Gram-
negative species caused infection in
16(6.7%) cases with 23.5% re-
infections and 12.5% mortality. In 63
(26.4%) cases a mixed genera
caused infection with 17.5% re-
infections and 1.6% mortality.
S.epidermidis infections were more
common in revision-to-spacer
procedures (23.1%) than in partial
revisions(11.4%). The distribution of
the remaining species did not differ
between surgical subgroups.
Conclusions: The most frequent ethiological agent
was s. aureus, but with a low rate of
MRSA. The highest re-infection rates
after revision surgery were found in
polymicrobial or gram-negative
infected knees.
155. Safety of Metal-on-Metal Articulation
Kim Pagh Sperling
Orthopedic Clinic, Aleris-Hamlet Copenhagen
Background: Results after MoM THAs are generally
good. Reports have emerged of
abnormal soft-tissue reactions to MoM
THAs and Total Hip Resurfacing (THR)
Purpose / Aim of Study: To assess the prevalence of
pseudotumours in patients, who have
received a large diameter MoM
prosthesis. To assess the revision rate
of large diameter MoM prosthesis. To
correlate these findings to the type of
prosthesis (THA versus THR).
Materials and Methods: 182 hips (160 patients), 103 THR
(Recap Biomet) (93 patients) and 78
MoM THA (uncemented Bi-Metric,
Biomet and Magnum head, Biomet)
(67 patients) were included in the
study designed as an observational
cross-sectional study. The follow-up
included a clinical hip examination,
standardized AP pelvic and lateral hip
radiographs, blood serum samples for
metal ion level of chrome and cobolt.
Patients with elevated metal ion levels
(119nmol/L for cobalt and 134,5
nmol/L chromium) or patients with
groin pain lasting at least one month
considers CT imaging indicated in
these patients.
Findings / Results: Mean observation 3,5 year (1-7). X-ray
showed two acetabular components
with retroversion (1 THA / 1 THR)
(elevated ion levels) underwent
revision. In total 14 patients (7 THA/7
THR) had elevated ion levels. These
and six patients with reaction pain from
the hip underwent CT scan (9 THA/ 11
THR). The CT scan showed one
pseudotumor (1227 nmol/L Cobalt and
1589 nmol/L Chromium) underwent
revision and one minor cyst without
clinical symptoms (123 nmol/L Cobalt
and 107 nmol/L Chromium) is still
under observation. One patient (THR)
with groin pain is additional revised.
Conclusions: The main subject was to find the
prevalence of cyst formation and
correlate to the types of MoM
prostheses (THA/THR). There was one
in the THA group and NS to the THR
group. Revision rate was 2,2 % (2
THA / 2 THR) NS and comparable to
traditional hip arthroplasty.
156. Mononucleated Bone Marrow Cells do not Survive During Long-Term in vitro Culture
Kris Chadwick Hede, Helle Lysdahl, Bjørn Borsøe Christensen, Martin Lind, Casper Bindzus Foldager
Orthopedic Research Lab, Aarhus University Hospital; Department of Sports Traumatology, Aarhus University Hospital
Background: The use of mononucleated cells in bone
marrow aspirate concentrate (BMAC) for
cartilage repair has shown promising early
clinical results. The mode of action of the
BMAC used with biodegradable scaffolds is
unknown.
Purpose / Aim of Study: The purpose of this study was to investigate
the chondrogenic differentiation of bone
marrow mononucleated cells (BM-MNCs) in
vitro. We hypothesized that the
chondrogenic response of BM-MNCs was
comparable to differentiated chondrocytes
following long-term culture.
Materials and Methods: BM-MNCs from 7 healthy donors were
isolated using Ficoll-Hypaque solution and
centrifugation. Chondrocytes were obtained
from 3 donors undergoing anterior cruciate
ligament reconstruction. BM-MNCs or
chondrocytes were seeded on Chondro-
Gide© scaffolds and cultured in HG DMEM
with 100 nM Dexamethasone, 50 μg/mL L-
Ascorbic Acid 2-Phosphate, 40 μg/mL L-
Proline, 1 mM Sodium Pyruvate, 1x ITS,
and 10 ng/mL TGFβ3 or DMEM-F12 with
10% FCS, respectively. Cellular distribution
in scaffolds was investigated by Hoechst
staining on day 7, 14, 21, 28, 42 and 56.
Findings / Results: A very limited number of BM-MNCs was
present in the scaffolds after 7 days and
after 28 days no viable cells were found. In
contrast, chondrocytes remained viable in
scaffolds cultured for 56 days. No RNA
could be extracted after 28 days from the
scaffolds on which the BM-MNCs had been
seeded; therefore the chondrogenic
response on mRNA level was not
investigated.
Conclusions: BM-MNCs cultured in chondrogenic medium
on Chondro-Gide© scaffolds do not remain
viable over the course of 28 days, and thus
do not undergo chondrogenic differentiation.
This suggests that the clinical benefits of
using BMAC in a one-step procedure with
scaffolds may exclusively be due to short-
term, humoral effects on native cells, and
not long-term proliferation and differentiation
of BM-MNCs.
157. Recurrent patellar dislocation in 37 adolescent knees treated with a modified Roux-Goldthwait procedure; a follow-up study with inferior results.
Lars Lykke Hermansen, Knud Gade Freund
Ortopædkirurgisk Afd., SVS Esbjerg
Background: Patients with recurring patellar dislocations
are often treated with stabilising surgery to
prevent additional events. In immature
patients with open growth zones, only soft
tissue operations are used in order not to
interfere with further growth. One of these
procedures is the Roux-Goldthwait
operation. Although the published literature
regarding this technique and immature
patients are sparse, it has shown very
good results through the last 115 years.
Nevertheless, it has been abandoned in
favour of various MPFL reconstruction
techniques.
Purpose / Aim of Study: The purpose of this study is to evaluate the
outcome after the Roux-Goldthwait
procedure in adolescent patients with open
growth plates.
Materials and Methods: Between 2000-2009, 37 adolescent knees
(30 patients) underwent surgery with the
Roux-Goldthwait technique due to
recurrent patella dislocation. Mean age
14,3 years (11,3–17,9 years). The same
surgeon performed all operations. Follow-
up was completed after a mean time of 6,6
years (2,6–11,8 years), with specific
interest in subsequent dislocation of the
patella. The patients were also evaluated
by a KOOS questionnaire.
Findings / Results: 28 patients answered (35 knees), whether
they have experienced patella dislocations
after surgery or not, and 26 patients (30
knees) returned the KOOS questionnaire.
2 patients (2 knees) were lost during
follow-up. 23 out of 35 knees had
experienced one/several patella
dislocation(s) during the follow-up period.
The average KOOS scores were; Pain =
81; Symptoms = 76; ADL = 85; Sport/Rec =
54; QOL = 54.
Conclusions: The present study supports the discarding
of the Roux-Goldthwait procedure in
immature patients. The majority of patients
experienced dislocations after their
operation. The study contradicts the
already published literature, properly due to
publication bias.
158. Success rates and failures after infectious revision knee arthroplasty in Denmark. A two year nationwide study.
Martin Lindberg-Larsen, Christoffer Calov Jørgensen, Jens Bagger, Henrik Schrøder, Henrik Kehlet
Department of Orthopaedic Surgery, Bispebjerg Hospital; Section of Surgical Pathophysiology, Rigshospitalet
Background: The surgical treatment of
peiprosthetic knee infection is
generally either a partial revision
procedure (open debridement and
exchange of tibial insert) or a two-
stage exchange arthroplasty
procedure.
Purpose / Aim of Study: To describe success rates and
failures of these procedures.
Materials and Methods: 573 knee arthroplasties revised due
to infection from 1st July 2011 to
30th June 2013 were identified from
the Danish Knee Arthroplasty
Register. Revisions from spacer to
spacer, one-stage total exchange
procedures, arthrodesis and femoral
amputations were excluded. 105
partial revisions, 218 revisions to
spacer and 212 spacer to revision-
TKA procedures were included in the
final analysis. Data on hospitalizations
and mortality were obtained from the
Danish National Patient Register.
Failure was defined as surgically
related death ¡Ü90 days
postoperatively or re-revision due to
re-infection (follow-up 396 days).
Findings / Results: Re-revision rate (due to re-infection)
was 24.8% and mortality rate was
2.8% resulting in a success rate of
72.4% after partial revisions. The
median time from partial revision to
previous arthroplasty procedure was
34 days, without differences in re-
revision rates between cases revised
within 28 days or later. Re-revision
rate was 9.2% and mortality was
4.6% after revision to spacer
procedures, whereas re-revision rate
was 12.7% and mortality 0.9% after
spacer to revision-TKA procedures.
Only 75.6% of the revision to spacer
procedures (first stage) performed
within our study period were later
successfully revised from spacer to
revision-TKA (second stage).
Conclusions: The success rate of 72.4% after the
partial revision procedure may be
acceptable taking the relative limited
surgical trauma in consideration,
whereas the success rate of 75.6%
of the resource-intensive two-stage
revisions may call for reconsideration.
159. Chemical neutralization of carry-over contaminants in the evaluation of topical antimicrobial effectiveness
Nikolaj Milandt, Tine Nymark, Søren Overgaard, Hans Jørn Kolmos
The Orthopaedic Research Unit, Department of Orthopaedic Surgery and Traumatology, Odense University Hospital; Department of Clinical Microbiology, Odense University Hospital
Background: Valid measurement of bacterial
quantities on human skin following
disinfection often requires the use an
appropriate neutralization system to
prevent carry-over contamination from
topical antimicrobials. Failure to
neutralize such contamination may result
in overestimation of disinfection
efficacy. Some active components are
known, but there is no consensus on an
effective formulation for neutralization
of chlorhexidine gluconate and iodophor.
Purpose / Aim of Study: The aim of this study was to validate
the formulation of a chemical
neutralization system for use when
sampling human skin prepared with
chlorhexidine gluconate or iodophor,
using the cylinder-sampling method.
Materials and Methods: The system was tested in accordance with
ASTM standard 1054-08. We performed the
test using an antiseptic challenge
solution collected from human skin with
the cylinder-sampling method. The skin
had been disinfected with chlorhexidine
gluconate in ethanol with and without
subsequent covering with an iodophor
impregnated incise drape prior to
sampling. A test organism (staph
epidermidis) was exposed to the
antiseptic challenger for 1 and 30
minutes, with and without added
neutralizer, and compared to a control.
The organism was also added to the
neutralizer alone, observing for toxic
properties.
Findings / Results: We observed complete neutralization of
carry-over chlorhexidine gluconate and
iodophor. Not adding the neutralizer
resulted in significant loss in
viability of the test organism. No
organism loss was observed during an
exposure time of 30 minutes to the
neutralizer alone.
Conclusions: The neutralizer formulation was an
effective chemical neutralizer of
carry-over contamination from
chlorhexidine gluconate in topical skin
disinfection products and iodophor from
iodine impregnated incise drapes in
samples collected using the cylinder
sampling method.
160. Changes in Bone Mineral Density of the Proximal Tibia After Uncemented Total Knee Arthroplasty. A Prospective Randomized Study Comparing a Novel Porous Titanium Construct (Regenerex) surface to a Well-Proven Porous- Coated Implant surface
Winther Nikolaj , Claus L Jensen, Thomas lind, Morten Boye Petersen, Henrik Schrøder, Michael Mørk Petersen
Orthopeadic, Rigshospitalet
Background: Regenerex is a novel porous titanium
construct with a 3-dimensional porous
structure and biomechanical characteristics
close to that of normal trabecular bone.It is
believed that these characteristics will
facilitate bone ingrowth and secure a better
fixation to the host bone, thus increasing the
implant survival.
Purpose / Aim of Study: The aim of this study was to evaluate the
adaptive bone remodeling of the proximal
tibia after uncemented total knee
arthroplasty (TKA) using a tibial tray with
this novel coating compared to a well-
proven standard porous coated (PPS) tibial
tray.
Materials and Methods: Sixty patients scheduled for TKA were
randomized to receive either a Regenerex
or a PPS tibial component. Changes in
bone mineral density (BMD) of the proximal
tibia were measured at 3, 6, 12 and 24
months by dual-energy x-ray absorptiometry
(DEXA).
Findings / Results: In the lateral region (ROI 3), a significant
increase in BMD was seen in both groups at
3, 6, and 12 months after surgery. The
relative increase at 12 months was 8.1% (P
=0.007) for the PPS group and 6.5% (P=
0.002) for the Regenerex group. Positive
values were retained at 24 months in both
groups. At 24 months BMD in the distal
region below the central stem (ROI 1), had
decreased in the PPS group by 3.4% (P=
0.005) and in the Regenerex group by 2.4%
(P=0.17). In the medial region (ROI 2) BMD
remained unchanged at all follow-up
evaluations in both groups. There were no
significant differences between the 2 groups
(P = 0.45).
Conclusions: The significant increase in BMD of the
lateral proximal tibia plateau with very
limited changes medially and distally seen
in both implants suggests that the novel
porous titanium construct and the PPS
implant have a pronounced beneficial effect
with regard to maintaining periprostetic
BMD in all regions of interest investigated.
161. Rising incidence of Bacteremia in a Danish Orthopedic Department
René Gren Hansen Voldby, Rolf Magnus Arpi, Jonas Bredtoft Boel
Department of Plastic- ,Breast- and Burnsurgery, Rigshospitalet; Department of Clinical Microbiology, Herlev Hospital
Background: Infections play an important role for the prognosis
of orthopedic patients with a high impact on length
of stay in the hospital, final mobility outcome and
quality of life. Bacteremia is the most severe and
life-threatening infection. The incidence of
bacteremia in orthopedic patients is poorly
elucidated.
Purpose / Aim of Study: To describe the incidence of bacteremia in the
Orthopedic Department at Herlev Hospital in the
15-year period 2000-2014.
Materials and Methods: Data about positive blood cultures was extracted
from the laboratory database at the Department of
Clinical Microbiology, Herlev Hospital. In patients
with more than one episode of bacteremia only the
first episode was included. Incidence of bacteremia
was calculated for the three 5-year periods 2000-
2004, 2005-2009 and 2010-2014 and reported as
number of bacteremic episodes per 1.000
occupied bed days.
Findings / Results: The incidence of bacteremia was 0.59, 1.13 and
1.74 per 1.000 occupied bed days in the periods
2000-2004, 2005-2009 and 2010-2014,
respectively. This almost 3-fold increase of the
incidence of bacteremia was highly significant
(p<0.001).
Conclusions: The rising incidence of bacteremia in orthopedic
patients is worrying and deserves further
investigation with focus on predisposing factors,
microbial etiology and resistance patterns.