Session 3: Knee
Torsdag den 24. oktober
09:00 – 10:30
Chairmen: Poul Torben Nielsen / Henrik Schröder
Morten Grove Thomsen, Henrik Husted, Thor Bechsgaard, Anders Troelsen
Dept. of Orthopedic Surgery, Copenhagen University Hospital of Hvidovre
Background: To achieve good clinical results and low
revision rates after TKA, traditional
recommendations have been to aim for
anatomical AP alignment (0-7°of valgus)
based on a perpendicular cut on the tibia.
Accordingly, “safe-zones” for component
position have been suggested. Recent
studies, however, have challenged the
suggested importance of these
Purpose / Aim of Study: To investigate 1) the rate of TKAs inside
traditional safe-zones of alignment and
component position, 2) if outlier TKAs are
associated with increased aseptic revision
Materials and Methods: By random selection 678 primary TKAs
inserted at our institution between 2007 and
2011 were included. 40 TKAs were
excluded because of previous knee surgery
or postoperative revision due to infection.
Pre- and postoperative radiographs were
assessed for anatomical alignment (AP) and
position of the individual components (AP
and sagittal). 15 of 638 TKAs (2.4%)
undergoing revision due to aseptic
complications were identified.
Findings / Results: Postoperative safe-zones were achieved for
AP alignment in 74%, femoral component AP
position in 68%, tibia component AP position
in 78%, and femoral component sagittal
position in 78%. We found no statistically
significant relationships between alignment
or component position outside safe-zones
and rates of revision due to aseptic
complications for AP limb alignment
(p=0.86), femur- and tibia AP component
positions (p=0.60 and p=0.87) and femur
sagittal component position (p=0.52).
Conclusions: Limb alignment and position of TKA
components within so-called “safe-zones” is
not an easy target. It seems that TKAs
outside the safe-zones are not associated
with increased risk of aseptic revision.
Further investigations looking at both long-
term functional outcomes and patient
satisfaction are needed.
Christian Wied, Morten Grove Thomsen, Lis Myhrmann, Lotte Skov Jensen, Henrik Husted, Anders Troelsen
Dept. of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre, Denmark
Background: Fast-track total knee arthroplasty
(TKA) has significantly shortened the
time available for physiotherapists to
optimize knee Range of Motion
(ROM) before discharge. Safety
aspects concerning knee stiffness and
the need for manipulation in a fast-
track setting need to be illuminated.
Purpose / Aim of Study: The study aims were to analyze if
fast-track TKA can be considered safe
considering rates of knee
manipulation and if there is an
association between knee ROM at
time of discharge and the need for
Materials and Methods: Primary TKAs operated in 2011 at
our institution were eligible for
inclusion (n=398). Of these, we
excluded 20 that had revision
surgery, and 19 that did not have
measurement of ROM at discharge.
The study group consisted of 359
TKAs (338 patients/ 65% females).
Knee manipulations within 1 year of
surgery were recorded.
Findings / Results: Manipulation of the knee was
performed in 21 of 359 knees (5.8%).
Median length of stay was 2 days.
The prevalence of knee manipulation
showed a statistically significant
association with the achieved knee
flexion at discharge (p=0.02): 13.6 %
if discharge flexion was < 70°, 6.6 %
if discharge flexion was 70°- <85°,
and 2.7 % if discharge flexion was ≥
85°. Only one of 66 TKAs with a
flexion ≥ 85° combined with an
extension deficit of ≤ 5° underwent
Conclusions: Compared with literature findings
fast-track TKA surgery may be
considered safe based on the
acceptable rate of knee
manipulations after TKA.
Combined knee ROM of ≤ 5°
extension deficit and ≥ 85° flexion
at time of discharge can be
considered a “safe-zone” with very
low risk of manipulation.
Extraordinary follow-up may be
warranted in TKAs with discharge
flexion < 70°.
Maiken Stilling , Claus Fink Jepsen, Lone Rømer, Ole Rahbek, Kjeld Søballe, Frank Madsen
Departmen of Orthopaedics, Aarhus University Hospital; Department of Radiolgy, Aarhus University Hospital
Background: The tibial component often has a stem
to aid fixation in the tibial bone.
Purpose / Aim of Study: The purpose of this study was to
compare implant fixation, periprosthetic
bone change, and clinical outcome of
tibial components with different stem
Materials and Methods: 54 patients/knees (15 males) with knee
osteoarthritis at a mean age of 77
years (70 – 90) were randomly
allocated to receive tibial components
with either an I-Beam stem (n=27) or a
finned stem (n=27) (CoCr modular
Tibial Tray Interlok, Biomet Inc). The
tibial component was cemented on the
cut surface (Palacos R bone cement)
but not around the stems. Five patients
(I-Beam stems) were lost to follow-up.
Implant migration (Model-Based RSA),
periprosthetic bone mineral density
(BMD), and American Knee Society
Score (AKSS) was evaluated through
5 years follow-up.
Findings / Results: At 5 years follow-up, total translation
(p=0.10) was 0.84mm (SD 0.76) and
0.45mm (SD 0.49), and total rotation
(p=0.08) was 1.51° (SD 1.27) and
0.81° (SD 0.85), for the I-beam stem
and the finned stem tibial components,
respectively. Between baseline and 1
year the peri-prosthetic BMD on AP
scans decreased 10% (0.09 g/cm2)
around I-beam and 2% (0.02 g/cm2)
around the finned stem components
(p=0.02). In the tibia below the stem
BMD decreased by 6% and increased
by 3% (p=0.01) at 1 year for the I-
beam and finned stem components,
respectively. At 2 years BMD loss
progressed in general in both groups.
5 year DXA data are currently being
analyzed. Knee score, function score,
pain, and satisfaction were similar.
Conclusions: RSA showed similar stability of the
tibial components with I-Beam and
finned stems at 5 years follow-up.
There was a heterogeneous BMD
changes between the groups at 2
years that may jeopardize implant
stability of the I-Beam stem and further
analyses in the 5 year data are
currently being done.
Ashir Ejaz, Anders C. Laursen, Andreas Kappel, Sten Rasmussen, Mogens B. Laursen, Poul T. Nielsen
Department of Orthopaedics , Aalborg University Hospital; Department of Orthopaedics, Aalborg University Hospital
Background: Use of pneumatic tourniquet to obtain a
bloodless surgical field for total knee
artroplasty (TKA) has always been highly
debated and many parameters such as pain,
bloodloss, range of motion, operation time
and complications have been investigated.
Achieving a stable fixation of the tibial
component is still a major challenge and
concern when doing TKA. Very little data
regarding implant fixation is available.
Purpose / Aim of Study: To investigate whether tibial component
fixation is compromised when tourniquet is
not used and active bleeding occurs during
TKA, assessed with radiostereometric
analysis (RSA) and plain radiographs.
Materials and Methods: A RCT with 70 consecutive patients aged
50-85 (mean= 68) underwent primary
unilateral TKA performed by a single
surgeon. Patients were randomly allocated
to one of two groups: Group A surgery with
tourniquet and Group B surgery without
tourniquet. Tantalum markers were placed in
the tibial metaphysis and implant and RSA
was performed postoperatively and at 2
months, 6months and 12 months.
Findings / Results: Plain radiograph were assessed for radio
lucent lines and RSA performed. All implants
appeared stable, except in one case of early
loosening otherwise no differences
between groups were observed.
Micromotions of more than 1 mm and 1º
were considered to be clinically relevant.
RSA endpoints were maximum total point
motion (MTPM), tibial subsidence, lift-off and
rotations and translations along the x-, y, z-
Conclusions: At 1 year follow up no cases of clinical
loosening of implants had been observed.
Performing TKA without use of tourniquet
does not seem to affect the fixation of the
cemented tibial component.
Toke Kirchberg Nilsson, Andreas Kappel, Anders Christian Laursen, Poul Torben Nielsen
Background: Uni-compartmental osteoarthritis of the
knee joint has a wide range of different
surgical treatment options including
uni-compartmental knee arthroplasty
(UKA), total knee arthroplasty (TKA) and
ACO is not included in the Danish
national registers for systematic
analysis, as surgical registry codes
cover several different procedures over
Purpose / Aim of Study: The study aims at estimating the Danish
activity of ACO, pre-surgical assessment
and surgical techniques.
Materials and Methods: A questionnaire survey among 42
orthopaedic departments and private
clinics in Denmark selected on the basis
of Danish Regions' and the Departments'
own reports. In case of doubt, regarding
a clinic's relevance to the survey, a
questionnaire was submitted.
Findings / Results: 34/42 (81%) responded to the survey.
Fifteen departments/clinics preform ACO
with a total national activity estimated
between 162 to 221 procedures/year
[range 1-70 for single clinics].
Twelve (80%) departments use open wedge
technique with internal fixation to
treat medial osteoarthritis. Seven (47%)
departments offer ACO (varus osteotomy)
in lateral osteoarthritis.
8/15 (53%) departments performing ACO
preform less than 6 procedures annually.
4/18 (22%) departments, that do not
offer ACO, offer UKA instead of ACO.
Conclusions: More then half the departments
preforming ACO have low annually
activity. The pre-surgical assessment,
indication for surgery and surgical
options are of wide national variation,
and we therefore propose to explore,
which pre-surgical assessment and
surgical procedure provide best outcome
in uni-compartmental knee osteoarthritis.
Anders Christian Laursen, Thomas Lind-Hansen, Mogens Berg Laursen, Poul Torben Nielsen
Orthopaedic Research Unit, Aalborg University Hospital; Dept. of Orthopaedics, Vejle Hospital; Dept. of Arthroplasty, Aalborg University Hospital
Background: In open-wedge, valgus osteotomy of the
upper tibia, there are concerns regarding
initial stability. Rehabilitation protocols vary
depending on the surgical technique, type of
implant, fixation method and tradition. Angle
stable implants theoretically offer initial
stability, and it has been indicated that early
full weight-bearing is feasible.
Purpose / Aim of Study: To validate early full weight-bearing in
patients with the Dynafix implant, by
means of radiostereometric analysis (RSA),
plain radiograph, and clinical outcome.
Materials and Methods: 26 consecutive primary open-wedge
valgus osteotomies were performed.
Patients were randomized at surgery
between two rehabilitation protocols, one
including full early weight-bearing, and
one with 6 weeks restricted weight-
bearing of 20 kgs. Migration and stability
of the osteotomy was measured by RSA,
post-operatively, at 6 weeks, and 1 & 2
years, with both reclining and
standing analysis. Plain radiographs and
clinical outcome (KOOS score) were
recorded at the same intervals.
Findings / Results: No difference in stability or retainment of
correction between the groups was
detected. All patients in both groups were
healed and stable in plain radiograph and
clinically fully healed at end of trial. No
significant differences in clinical outcome
scores or pains were recorded: In both
groups, pain and function improved
substantially. Patients in the early weight-
bearing group achieved the same clinical and
radiological outcome of surgery, with faster
and more convenient rehabilitation
Conclusions: Open-wedge high tibia valgus osteotomy
using the Dynafix implant allows early full
weight-bearing, without risk of instability or
clinicallly relevant loss of corrrection, and
with similar clinical outcome compared with
Maiken Stilling, Frank Madsen, Claus Fink Jepsen, Kjeld Søballe, Per Wagner Kristensen, Anders Odgaard
Department of Orthopaedics, Aarhus University Hospital
Background: The Cementless Oxford® Partial Knee
Tibial Tray (TT) was introduced to the
commercial market 5 years ago.
Purpose / Aim of Study: To compare fixation of cementless and
cemented (gold standard) Oxford®
Partial Knee TT up to 2 years follow-up
by radiostereometric analysis (RSA).
Materials and Methods: 79 patients (48 men) were randomly
allocated to surgery with cementless
hydroxyapatite-coated or cemented
Oxford® Partial Knee TT (Biomet Inc.)
at 2 hospital sites. Femoral
components were either single-pegged
or double-pegged in the cemented
group and double-pegged in the
cementless group. Refobacin bone
cement (Biomet Inc.) was used.
Evaluation of implant migration,
radiolucent lines (RLL), and clinical
outcomes (OKS) was performed at 6
weeks, 3 and 6 months, and 1 and 2
Findings / Results: Between 1 and 2 years follow-up
cementless TT (n=25) migrated
0.06mm (sd 0.06) and cemented TT
(n=45) migrated 0.12mm (sd 0.20)
mean total translation (p=0.22). 13%
(6/39) of cemented and 8% (2/25) of
cementless TT migrated more than
0.2mm between 1 and 2 years follow-
up (p=0.40). The cementless TT
(n=25) migrated more than the
cemented TT (n=55) at all follow-ups
(p<0.01), however migration had
stabilized at 6 months follow-up. At 2
years mean OKS was 40 (range 21-
47) (p=0.53) with similar improvement
from baseline (p=0.11) and satisfaction
was high in both groups. Analysis of
RLL at 2 years follow-up is ongoing.
Conclusions: Cementless Oxford® Partial Knee TT
migrate initially but stabilize at 6
months probably because of achieved
bony anchorage. Between 1 and 2
years follow-up cementless fixation is
as good as cemented fixation (gold
standard). Functional results were
good and similar in both groups.
Thomas Bandholm, Kristian Thorborg, Troels Haxholdt Lunn, Henrik Kehlet , Thomas Linding Jakobsen
(1) Physical Medicine & Rehabilitation Research – Copenhagen (PMR-C), Department of Physical Therapy, Copenhagen University Hospital, Hvidovre; (1) Arthroscopic Centre Amager, Department of Orthopedic Surgery, (2) Physical Medicine & Rehabilita, Copenhagen University Hospital, Hvidovre; (1) Department of Anesthesiology, (2) The Lundbeck Foundation Centre for Fast-Track Hip and Knee Art, Copenhagen University Hospital, Hvidovre; (1) Section for Surgical Pathophysiology, (2) The Lundbeck Foundation Centre for Fast-Track Hip and , Rigshospitalet; (1) Lundbeck Foundation Centre for Fast-Track Hip and Knee Arthroplasty, Copenhagen, (2) Physical Me, Copenhagen University Hospital, Hvidovre
Background: Loading and contraction failure
(muscular exhaustion) are strength
training variables known to influence
muscle strength and muscle mass gains in
healthy subjects, and may have potential
benefits for rehabilitation after total
knee arthroplasty (TKA).
Purpose / Aim of Study: To investigate the effect of loading and
contraction failure on knee pain during
strength training, shortly following TKA.
Materials and Methods: Seventeen patients (72.0 ± 10.7 yrs, 11
women) were included 1 to 2 weeks after
their TKA. In a randomized order, they
performed 1 set of 4 standardized knee
extensions, using relative loads of 8,
14, and 20 repetition maximum (RM) (load
experiment), and ended with 1 single set
to contraction failure (14 RM load)
(failure experiment). The kilograms,
corresponding to the 8, 14, and 20 RM
loadings, were determined no less than
72 hours prior, during a familiarization
session. The patients rated their knee
pain during each repetition, using a
numerical rating scale. Patients as well
as the pain assessor were blinded to the
loads. 1.5 points was pre-specified as
the minimal clinically important change
in pain, and used to power the study.
Findings / Results: Two patients were lost to follow up.
Knee pain increased with increasing load
(20 RM: 3.1 ± 2.0, 14 RM: 3.5 ± 1.8, 8
RM: 4.3 ± 2.5, P=0.006), and repetitions
to contraction failure (10% failure: 3.2
± 1.9, 100% failure: 5.4 ± 1.6,
P<0.001). Resting knee pain 60 seconds
after the final repetition (2.7 ± 2.4)
was no different from that recorded
before strength training (2.7 ± 1.8,
Conclusions: Repetitions performed to contraction
failure during knee extension strength
training seems to induce a clinically
relevant – but transient – increase in
post-operative knee pain during strength
training, shortly following TKA.
Martin Lindberg-Larsen, Christoffer Calov Jørgensen, Torben Bæk Hansen, Søren Solgaard, Anders Odgaard, Henrik Kehlet
Section of Surgical Pathophysiology and The Lundbeck Centre for Fast-track Hip and Knee Arthroplasty, Rigshospitalet; Department of Orthopedic Surgery and The Lundbeck Centre for Fast-track Hip and Knee Arthroplasty., Holstebro Hospital
Background: Limited data exist on early outcomes
after revision total knee arthroplasty
(TKA) (1,2) , and especially with a fast-
track set-up (2).
Purpose / Aim of Study: To investigate length of stay (LOS),
readmissions and mortality ¡Ü 90 days
after aseptic revision TKA in Denmark
Materials and Methods: All patients undergoing TKA revision
procedures in DK from 01.10.2009 to
30.09.2011 were analyzed using the
Danish National Patient Registry with
additional information from the Danish
Knee Arthroplasty Registry. Only
elective, aseptic revisions were included.
The revisions were subdivided into 3
groups: 1. Replacement of both tibia-
and femur components, 2. Replacement
of one of the components (tibia or
femur), 3. Replacement of the liner,
patellar button or secondary insertion of
the patella button.
Findings / Results: 1042 aseptic TKA revision procedures
were performed in 42 centres in DK in
the study period. Mean age was 65.7
(range: 27-92), median LOS 6 days
(IQR: 4-10), mean LOS 8.5 (1-120) days,
90 days readmission rate 12.5 % and 90
days mortality 0.6 %. In group 1 (n =
713) median LOS was 7 days (4-10),
readmission rate 12.5 % and mortality
0.8 %. In group 2 (n = 150) median LOS
was 5 days (3-10) and readmission rate
16.0 %. In group 3 (n = 179) median
LOS was 5 days (4-9) and readmission
rate 9.5 %. No deaths in group 2 and 3.
Conclusions: Revision TKA procedures are performed
in multiple centres in DK and the fast-
track methodology is not implemented in
relation to these procedures, calling for
improvement. A multicenter study on
revision TKA in a fast-track setting is in
the planning phase.
(1): Cram P et al. Total knee arthroplasty
volume, utilization, and outcomes among
medicare beneficiaries, 1991-2010.
(2): Husted H et al. Fast-track revision
knee arthroplasty. A feasibility study.
Acta Orthop. 2011;82:438-40.
Erik Malchau, Kirill Gromov, Henrik Husted, Henriks Malchau, Anders Troelsen
Orthopaedic Surgery, Copenhagen University Hvidovre Hospital
Background: Registry data from multiple countries have
documented an ongoing shift in THA fixation
towards uncemented fixation despite reports
of inferior survivorship. Similar paradoxical
trends in TKA surgery could be a concern.
Purpose / Aim of Study: To investigate: 1) current trends in TKA
fixation and cruciate ligament retention, and
2) if these trends are in accordance with
registry reported TKA survival.
Materials and Methods: Data regarding tibia component fixation,
cruciate ligament retention (CR vs. PS) and
implant survivorship in primary TKA were
extracted from publicly available national
joint registries’ annual reports from 2008
through 2012. Reports from Australia (AUS),
Denmark (DK), England-Wales (E-W),
Norway (NOR), Sweden (SWE) and New
Zealand (NZ) were assessed.
Findings / Results: During the 5-year period an increase in
cemented fixation was reported by AUS
(76% to 77%), DK (93% to 94%) and E-W
(90% to 95%). A decrease in cemented
fixation was observed in NOR (82% to 78%)
and SWE (100% to 96%). NZ reported no
change. AUS, DK, E-W, NOR, NZ and SWE
reported significantly higher risks of revision
comparing uncemented with cemented
fixation. AUS reported an increase in the use
of PS TKA and E-W reported no change.
Both countries and DK reported a higher risk
of revision for PS vs. CR TKA.
Conclusions: Cemented TKA still appears to be the gold
standard in TKA surgery in most countries.
However, there were considerable regional
differences in current use of uncemented
TKA (4-23 %). Countries with increases,
though small in absolute numbers, in
utilization of uncemented fixation and PS
TKA should monitor this as it could result in
deteriorating survivorship over time.
Ashir Ejaz, Anders C. Laursen, Andreas Kappel, Poul T. Nielsen, Sten Rasmussen
Department of Orthopaedics , Aalborg University Hospital; Department of Orthopaedics, Aalborg University Hospital
Background: Use of tourniquet to obtain a bloodless
surgical field during TKA is known to induce
ischemia, especially beneath the cuff. Little
is known regarding the extent of ischemia
and metabolic changes in the skeletal muscle
distal to the cuff. Microdialysis (MD) is a
unique In vivo technique to monitor
metabolites in the interstitial space of the
tissue of interest.
Purpose / Aim of Study: Investigate the metabolic changes during
ischemia and reperfusion in skeletal muscle
distal to the tourniquet
Materials and Methods: A RCT with 70 consecutive patients aged
50-85 (mean= 68) underwent primary
unilateral TKA. Patients were randomly
allocated to one of two groups: Group A
surgery with tourniquet and Group B
surgery without tourniquet. Prior to
surgery, MD catheters were inserted in
the gastrocnemius muscle of both legs,
non-operated leg served as reference.
Dialysate samples were collected before
and until 5hours after surgery at intervals
of 20 min. Concentrations of ischemia
markers pyruvate, glucose, lactate,
glycerol were analysed.
Findings / Results: In group A, for a period of 60-75 min of
tourniquet induced ischemia interstitial levels
of pyruvate and glucose decreased
significantly to 26 µmol/l CI95%[24;31] and
2,3 mmol/l CI95%[2;3] respectively,
compared to the reference leg.
Simultaneously, accumulation of lactate to
2,6 mmol/l CI95%[2,3;3,1] and glycerol 244
µmol/l CI95%[200; 249] were observed.
A return to normal baseline values occurred
during a period of 120-180 min. After 5
hours no changes were detected compared
with baseline. In Group B no significant
ischemia was detected.
Conclusions: We determined that performing TKA with
tourniquet is associated with significant
ischemia in the muscle distal to the cuff and
ischemia markers are affected until 2-3
hours after surgery. Tourniquet induced
ischemia may impair early recovery.