Session 7: Knee
Torsdag den 23. oktober
13:00 – 14:30
Lokale: Reykjavik
Chairmen: Jakob Klit / Frank Madsen
61. Feasibility and safety of intensive weight loss before total knee replacement in obese patients: A randomized controlled trial
Anette Liljensøe, Jens Ole Laursen, Henning Bliddal, Kjeld Søballe, Inger Mechlenburg
Department of Orthopedics, Aarhus University Hospital; The Parker Institute, Department of Rheumatology, Copenhagen University Hospital, Bispebjerg-Frederiksberg
Background: Annually 8500 total knee replacements
(TKR) are performed in Denmark.
About 80% of this population is
overweight or obese. The present
material is part of a longitudinal
randomized study. ClinicalTrial.gov:
NCT01469403
Purpose / Aim of Study: To investigate whether it is feasible
and safe to implement an intensive
weight loss program in order to reduce
preoperative body weight of obese
patients before total knee replacement
(TKR) surgery.
Materials and Methods: We conducted a pragmatic, single-
blind, single-center randomized study.
Eligible patients were scheduled for
TKR due to osteoarthritis (OA) of the
knee and obesity (BMI > 30kg/m2).
Participants were randomized to either
a control group that followed the
standard care or a weight loss group
that followed a low-energy diet (810
kcal/day) 8 weeks before TKR.
Outcomes were assessed before
intervention for the weight loss group,
and within 1 week preoperatively for
both the weight loss group and the
control group.
Findings / Results: Included were 77 patients (weight loss
group n=38; control group n=39), 71%
were females, the mean age was 65
years (range 46-85), and the average
BMI was 31. The average weight loss
after 8 weeks was 10.7 kg. According
to dual energy X-ray absorptiometry
(DXA), the weight loss consisted of a
6.7 kg reduction in fat mass, a 3.0 kg
reduction in lean body mass, and lean
body mass increased by 2.3%. The
intensive diets had few and mild
adverse effects. Serious cardiac
complications were found in two cases
in the intervention group and in one
case in the control group. All three
patients later underwent TKR without
complications. No perioperative
complications were recorded in any
group.
Conclusions: Our results show that it is feasible and
safe to implement a weight loss
program shortly before TKR.
62. Efficacy of preoperative progressive resistance training on postoperative functional capacity and muscle strength in patients undergoing total knee arthroplasty
Birgit Skoffer, Thomas Maribo, Inger Mechlenburg, Per Møller Hansen, Kjeld Søballe, Ulrik Dalgas
Institute of Clinical Medicine and Department of Physical and Occupational Therapy, Aarhus University and Aarhus University Hospital; MarselisborgCentret, Danish Rehabilitation Research Centre; National Public Health and Quality Impro, Central Denmark Region, Aarhus and Aarhus University; Institute of Clinical Medicine and Orthopaedic Research Centre, Aarhus University and Aarhus University Hospital; Orthopaedic Department, Silkeborg Regional Hospital; Orthopaedic Research Centre, Aarhus University Hospital ; Section of Sport Science, Department of Public Health, Aarhus University
Background: Reduced knee extensor muscle strength and
associated impaired functional capacity is a
common clinical finding in people with knee
osteoarthritis. Furthermore, knee extensor
muscle strength is a strong predictor of
functional capacity one year after total knee
arthroplasty (TKA).
Purpose / Aim of Study: To investigate the efficacy of 4 weeks of
preoperative and 4-week post-operative
progressive resistance training (PRT)
compared to 4 weeks of postoperative PRT
alone in patients undergoing total knee
arthroplasty. Outcomes were functional
capacity, muscle strength and patient
reported outcomes.
Materials and Methods: In a single-blinded, clinical, randomized,
controlled trial, 59 patients were randomized
to 4 weeks of preoperative PRT (PRT group)
or to a control group who “lived as usual”
(control group). All patients performed 4
weeks of PRT after TKA. At 6 weeks before
TKA, and at 6 weeks after TKA functional
capacity, knee extensor and flexor muscle
strength, patient reported functional
capacity, health related quality of life, pain
scores and medication was registered.
Findings / Results: A significant group difference was found in
favor of the PRT group for the 30sec-sit-to-
stand test (3.5± 1.2 rep; p<0.01), the timed-
up-and-go test (-1.56± 0.64 sec.; p<0.05), in
knee extensor muscle strength (19.3± 6.4
Nm; p<0.01) and in knee flexor muscle
strength (16.0± 5.5 Nm, p<0.01) when
evaluated 6 weeks after TKA. No
differences were found between groups on
patient reported outcomes except for the
KOOS sport subscale (13.6± 6.6 p<0.05)
favoring the PRT group.
Conclusions: Preoperative PRT is an effective intervention
improving postoperative functional capacity
and muscle strength but not patient reported
outcomes, without worsening pain or
increasing medication in patients undergoing
TKA.
63. EOS imaging for assessing lower limb alignment and implant positioning after Total Knee Arthroplasty (TKA)
Kirill Gromov, Viktor Hansen, Dov Goldvasser, Orhun Muratoglu, Henrik Malchau, Anders Troelsen
Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Harris Orthopaedic Laboratory, Massachusetts General Hospital
Background: The lower limb axis and implant alignment
are traditionally assessed to evaluate the
success of primary TKA surgery. EOS
imaging is a novel technology that can
provide the surgeon with full body images,
while exposing the patient to significantly
lower radiation dosage
Purpose / Aim of Study: In this study we seek to evaluate the
precision of EOS imaging for measuring
lower limb axes as well as implant alignment
following primary TKA
Materials and Methods: 32 patients that underwent TKA and had
EOS radiography performed pre- and
postoperatively were included in the study.
Hip-Knee-Ankle (HKA) axis and tibiofemoral
angle (TFA) was measured pre- and
postoperatively. Tibial and femoral implant
alignment was assessed in anterior-
posterior (AP) and lateral plane in respect to
anatomical as well as mechanical axis. Two
readers each assessed all images with
reassessment by one reader.. Intra- and
inter-reader variability was assessed by the
mean difference and 95% limits of
agreement (LoA)
Findings / Results: 95% LoA for postoperative HKA and TFA
were +/- 0.41° and +/-0.80°, respectively.
95% LoA for AP implant alignment in respect
to the mechanical axes were all within
+/-0.80° and within +/-1.47° in respect to
anatomical axes. 95% LoA for tibial lateral
implant alignment were within +/-1.50° and
within +/-3.65° for femoral lateral implant
alignment. There were no systematic
differences between observers.
Mean difference and LoA for tibial
component alignment in the AP plane in
respect to the mechanical compared to
anatomical axis was -0.18° +/-2.86°
Conclusions: EOS imaging can be used for precise
measurements of lower limb axis and
implant alignment following primary TKA.
This allows EOS imaging to be potentially
implemented as a clinical tool for evaluation
of results following TKA
64. Early progressive strength training to enhance recovery after fast-track total knee arthroplasty. A randomized controlled trial
Thomas Linding Jakobsen, Henrik Kehlet, Henrik Husted, Janne Petersen, Thomas Bandholm
Lundbeck Foundation Centre for Fast-track Hip and Knee Arthroplasty, Clinical Research Centre, Physi, Hvidovre Hospital, University of Copenhagen; Section for Surgical Pathophysiology 4074, Lundbeck Foundation Centre for Fast-track Hip and Knee Ar, Rigshospitalet, University of Copenhagen; Department of Orthopaedic Surgery, Hvidovre Hospital, University of Copenhagen; Clinical Research Centre, Hvidovre Hospital, University of Copenhagen; Physical Medicine and Rehabilitation Research - Copenhagen (PMR-C), Department of Physical Therapy, , Hvidovre Hospital, University of Copenhagen
Background: A pronounced loss of muscle strength
and functional performance has been
found after total knee arthroplasty (TKA).
A rehabilitation modality known to
increase muscle strength and functional
performance over time - such as
progressive strength training (PST) -
seems rational to enhance recovery after
TKA. However, the effect of
rehabilitation with PST has not been
investigated in a large assessor-blinded
randomized controlled trial.
Purpose / Aim of Study: To compare 7 weeks of supervised
rehabilitation with or without PST
commenced early after fast-track TKA on
functional performance.
Materials and Methods: Eighty-two patients with a unilateral
primary TKA were randomized to 7
weeks of supervised rehabilitation with
(PST-group) and without (CON-group)
PST commenced early after fast-track
TKA. The primary outcome was the
maximal distance walked in 6 minutes (6-
minute walk test). Secondary outcomes
were lower limb strength and power,
knee joint effusion and range of motion,
knee pain and self-reported disability and
quality of life. All outcome measures
were assessed before (baseline) and 4,
8 and 26 weeks after TKA.
Findings / Results: There was no statistically significant
difference between the PST- and CON-
group 8-week postoperatively (primary
endpoint) for the 6-minute walk test (mean
difference between groups: -11.3 meters,
95% confidence interval -45.4 to 22.7
meters; analysis of variance , p=0.51).
There were no statistically significant or
clinically meaningful differences between
groups in change scores from baseline to
any other time point for all secondary
outcomes.
Conclusions: Seven weeks of supervised rehabilitation
with PST was not superior to 7 weeks of
supervised rehabilitation without PST in
improving functional performance, measured
as the maximal walking distance in 6
minutes, at the primary endpoint 8 weeks
after fast-track TKA.
65. Bone remodelling of the of the tibia after total knee arthroplastry with uncemented tibia implants
Mikikel Rathsach Andersen, Nikolaj Winther, Thomas Lind, Henrik Schrøder, Michael Mörk Petersen
Knæklinikken, Ortopædkirurgisk afdeling, Gentofte Hospital, Region Hovedstaden; Ortopædkirurgisk klinik U, Hovedortocenteret, Rigshospitalet, Region Hovedstaden
Background: Loss of bone stock as a response to
the bone trauma and postoperative
immobilisation is a well known
complication to joint replacement
surgery.
Purpose / Aim of Study: This study investigates the adaptive
bone remodelling of the tibia, after total
knee arthroplasty (TKA) with two
uncemented total knee arthroplastries.
Materials and Methods: We performed 1 year follow up of 54
patients (mean age 61,7 (38-70) years,
28/26=x/y, BMI 29,5) that received an
uncemented TKA in a prospective
randomised controlled trial, where the
patients were randomised into two
groups that recieved different tibial
components.
The TKAs were performed using the
uncemented Zimmer Nexgen®
trabecular metal tibia implants with
either a monoblock (A) or modular (B)
polyethylene design.
Measurements of bone mineral density
(BMD) were done postoperatively and
after 3, 6, and, 12 months. BMD was
measured in 3 regions of interest (ROI)
medially, laterally, and distally around
the tibial component.
Statistics: Paired and unpaired t-test
(P< 0.05 were considered significant).
Findings / Results: Significant changes in BMD after 12
months of follow-up was only seen in
group A, where BMD decreased
medially by 9.4% (p=0.002) and
laterally by 6.7% (p=0.009). When
comparing BMD changes between the
groups after 12 months differences
was found in the medial (p=0.01) and
lateral (p=0.053) ROIs.
Conclusions: A significantly different bone
remodelling pattern of the proximal
tibia was seen in the two groups with a
higher degree of bone loss seen in
knees that received the monoblock
design.
66. Similar polyethylene wear of cementless and cemented Oxford Partial Knee’s at 2 years follow-up. A Randomized RSA Study
Maiken Stilling, Anders Odgaard , Claus Fink Jepsen, Kjeld Søballe, Per Wagner Kristensen, Frank Madsen
Department of Orthopaedic Research, Aarhus University Hospital; Department of Orthopaedics, Copenhagen University Hospital Gentofte
Background: Wear of polyethylene is a significant
cause of revision surgery in partial
knee replacement. The Oxford Partial
Knee has a fully-congruent, mobile,
polyethylene (PE) bearing designed to
minimize wear. Well-functioning knees
have low PE wear, but impingement or
incongruous articulation may affect the
wear rate. Cementless components
are hydroxyapatite coated, which may
risk higher polyethylene wear.
Purpose / Aim of Study: To compare PE wear of cementless
(CL) and cemented (C) Oxford Partial
Knee’s at 2 years by radiostereometric
analysis (RSA).
Materials and Methods: 80 patients (48 men) were randomly
allocated to surgery with CL
hydroxyapatite-coated (n=25) or C
(n=55) Oxford Partial Knee’s (Biomet
Inc.) and UHMWPE at 2 hospital sites.
Refobacin bone cement (Biomet Inc.)
was used. Evaluations of PE wear
(model-based RSA y-translation,
weight bearing set-up) and clinical
outcomes (OKS, AKSS) was
performed between baseline and 2
years.
Findings / Results: At 2 years followup mean PE wear of
0.43 (sd 0.98) mm in cementless
knees was similar (p=0.10) to 0.11 (sd
1.08) mm in cemented knees. The
wear rate including creep was 0.21 (sd
0.48) mm in cementless knees and
0.06 (sd 0.54) mm in cemented knees
(p=0.10). PE wear did not correlate to
age (p=0.45), OKS (p=0.54), pain in
general (p=0.61), pain during work
(p=0.50), side instability (p=0.67), knee
axis (p=0.96), walking aids (p=0.50) or
patient reported walking distance
(p=0.27). At 2 years mean OKS was
40 (range 21-47) (p=0.53) with similar
improvement from baseline (p=0.11).
Satisfaction was high in both groups.
No revisions.
Conclusions: Cementless Oxford Partial Knee’s had
a tendency towards higher PE wear at
2 years followup, and all knees had
higher wear rate than reported for well-
functioning partial knees in the
literature. Functional results were good
and similar in both groups.
67. Does knee awareness differ between knees in bilateral simultaneous TKA? Predictors of high knee awareness.
Katrine Abildgaard Nielsen, Morten Grove Thomsen, Roshan Latifi, Thomas Kallemose, Henrik Husted, Anders Troelsen
Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre, Denmark
Background: Low knee awareness during activities of
daily living has become the primary goal
when evaluating outcome after Total
Knee Arthroplasty (TKA). However, it is
still unclear how patient derived factors
(e.g. knee alignment) influence
postoperative knee awareness and
functional outcome. The Forgotten Joint
Score (FJS) evaluates to what extent the
patient is aware of the artificial knee and
thereby, whether the knee feels natural
or not.
Purpose / Aim of Study: To evaluate knee awareness of patients
undergoing bilateral simultaneous TKA and to
clarify the factors that predict a high or low
score.
Materials and Methods: This cross sectional study was
conducted on 120 simultaneous bilateral
TKAs (cemented CR AGC, Biomet)
performed at our institution between
2008 and 2012 (2-6 years follow-up). All
patients received 1 set of questionnaires
(FJS and Oxford Knee Score (OKS)) for
each knee. 99 patients (45 men, 54
women, mean age at operation 66,6
years) completed the survey and were
eligible for analysis. Based on FJS
scores patients’ knees were divided into
two groups - “best” and “worst” knees.
The FJS and OKS scores were
compared between groups.
Findings / Results: The absolute difference in FJS and OKS
score between the knees within each
patient was calculated, a non-parametric
bootstrap was used to create a 95 %
confidence interval (CI) for the median of
these differences. The results was a median
of 1 (CI: 0-4) for the FJS score and 1 (CI: 0-
1) for the OKS score. A predictive model
found that KL-score (p=0.006) and
preoperative knee-alignment (p=0.017) had a
significant effect on FJS score.
Conclusions: Knee awareness and functional outcome did
not differ significantly between the best and
worst knee in patients undergoing bilateral
simultaneous TKA. More severe
preoperative varus alignment and more
severe KL-grades predict lower knee
awareness after TKA.
68. Evaluation of peri-implant bone mineral density changes after femoral osseointegrated prosthesis surgery
Rehne Lessmann Hansen, Peter Holmberg Jørgensen, Kjeld Søballe, Klaus Kjær Petersen, Maiken Stilling
Department of orthopaedic research, University Hospital of Aarhus; Department of orthopaedic surgery, University Hospital of Aarhus
Background: Trans-femoral amputees have reduced bone
mineral density (BMD) in the residual femur,
hip and ipsilateral pelvis. Insertion of an
osseointegrated (OI) prosthesis may affect the
BMD additionally.
Purpose / Aim of Study: To study the effects of unloading/loading and
stress shielding after OI-prosthesis surgery.
Materials and Methods: 20 patients (13 males) mean age 48 (range
30-66) years, were operated with an OI
femoral implant in two stages. DXA scans were
performed at baseline and at intervals of 3, 6,
9, 12, 18 months postoperatively. The first 9
months partial weight bearing (PW) was
allowed, and after 9 months full weight bearing
(FW) was encouraged. The femoral peri-
implant bone was evaluated in 3 regions of
interest (ROIs), proximally (Rp), medially (Rm)
and laterally (Rl) to OI implant.
Findings / Results: From baseline to 18 months follow-up total
peri-prosthetic BMD was unchanged (p=0.44).
However, during PW periprosthetic BMD
decreased (p=0.005) 25% and during FW
BMD increased (p=0.04) 17%.
All 3 periprosthetic ROIs had a decrease in
BMD (p<0.0007) during the PW rehabilitation
period of 30%, 20% and 24% for Rp, Rm and
Rl, respectively.
During FW rehabilitation BMD increased
(p<0.04) in Rp 19% and in Rm 14%, whereas
the BMD in Rl was similar (p=0.06). However,
baseline values were not reached at 18
months.
Conclusions: Unloading, or less than full weight bearing, in
the first 9 months after IO implantation causes
pronounced stress-shielding and peri-implant
BMD loss. Increased or full loading between 9
and 18 months increases BMD, but not to
baseline values. Patients will be followed to
investigate if direct femoral bone loading from
the OI implant will result in continued BMD
increase of the peri-implant bone.
69. Functional capacity is associated with both extensor and flexor strength in patients scheduled for total knee arthroplasty: a cross-sectional study
Birgit Skoffer, Ulrik Dalgas, Inger Mechlenburg, Kjeld Søballe, Thomas Maribo
Institute of Clinical Medicine and Department of Physical and Occupational Therapy, Aarhus University and Aarhus University Hospital; Section of Sport Science, Department of Public Health, Aarhus University; Institute of Clinical Medicine and Orthopaedic Research Centre, Aarhus University and Aarhus University Hospital; Orthopaedic Research Centre, Aarhus University Hospital; MarselisborgCentret, Danish Rehabilitation Research Centre; National Public Health and Quality Impro, Central Denmark Region and Aarhus University
Background: Impairment of the knee extensor muscle
strength in patients with knee osteoarthritis
(OA) is well documented. Furthermore, pain
and reduced functional capacity in
combination with radiographically confirmed
severe OA are the main indications for total
knee arthroplasty (TKA).
Purpose / Aim of Study: To test in people scheduled for TKA if
muscle strength would be 1) strongly
associated with both objectively
measured functional capacity and
patient-reported measures; 2) more
closely associated with lower extremity
function when measured during
concentric than during isometric
contractions and; and 3) more strongly
related to the 30-sec-sit-to-stand
(30sSTS) test than to the timed-up-and-
go (TUG) and walking tests.
Materials and Methods: In fifty nine patients (70.4±6.8 years).
Associations between muscle strength and
objectively measured functional capacity and
patient reported outcomes were calculated.
Findings / Results: Both knee extensor and knee flexor strength
were associated with functional capacity
outcomes. Generally, the isokinetic knee
flexor muscle strength was more strongly
associated with functional capacity than the
isometric knee flexor strength. Isokinetic and
isometric knee extensor strength were of
equal importance. The 30sSTS test was
better than the TUG and the walking tests at
determining muscle strength.
Conclusions: Knee extensor and knee flexor muscle
strength and functional capacity are
generally associated. Focus on knee
extensor and knee flexor muscle strength is
of equal importance to improve or maintain
functional capacity. Furthermore, the
30sSTS test was found to be the best proxy
measure of muscle strength when more
advanced equipment for measurement of
muscle strength is not available.
70. Does knee awareness differ between different TKA designs? A matched, case-control, cross-sectional study.
Morten Grove Thomsen, Roshan Latifi, Thomas Kallemose, Henrik Husted, Anders Troelsen
Dept. of Orthopedic surgery, Copenhagen University Hospital of Hvidovre, Denmark
Background: Low knee awareness after TKA has become
the ultimate goal in trying to achieve a
natural feeling knee that meet patient
expectations. To accommodate this
manufacturers of TKAs have developed
new prosthetic designs that potentially could
give patients a more natural feeling knee
during activities.
Purpose / Aim of Study: To compare the Forgotten Joint Score (FJS)
and Oxford Knee Score (OKS) of patients
treated with a previous generation standard
CR TKA to the scores obtained by patients
treated with a newer generation CR TKA or
a mobile bearing CR TKA.
Materials and Methods: We identified all patients receiving a new
generation CR TKA or mobile bearing TKA
at our institution between 2010 and 2012.
These were matched to a population of
patients receiving a standard CR TKA
regarding age, gender, year of surgery, KL-
grade and pre- and postoperative knee
alignment. Patients were asked to complete
the FJS and OKS questionnaires. Of the
316 patients completing the survey 64
standard CR TKAs to 45 new generation
CR TKAs and 121 standard CR TKAs to 68
mobile bearing TKAs were matched. The
FJS and OKS scores of the three TKA
designs were compared.
Findings / Results: When comparing the new generation CR
TKAs to the standard CR TKAs we found
statistically significant higher OKS and FJS
scores (6 (p=0.04) and 16 (p=0.03) points
respectively) for the new generation CR
TKAs. When comparing the mobile bearing
TKAs to the standard CR TKAs we found a
statistically significant higher OKS score (3
points, p=0.04), and a higher FJS score (4
points, p=0.48) for the mobile bearing TKAs.
Conclusions: Patients receiving the new generation CR
and mobile bearing CR TKAs obtained
higher FJS and OKS scores when
compared to patients receiving a standard
CR TKA, indicating that the use of these
newer prosthetic designs facilitate less knee
awareness and better function after TKA.
71. Composition of The Knee Index, a novel three-dimensional biomechanical index for knee joint load, in subjects with mild to moderate knee osteoarthritis
Brian Clausen, Thomas Andriacchi, Dennis Brandborg Nielsen, Ewa Roos, Anders Holsgaard-Larsen
Department of Sports Science and Clinical Biomechanics, University of Southern Denmark; Department of Mechanical Engineering, Department of Orthopedic Surgery, Stanford University, Stanford, USA; Veterans Administration, Palo Alto; Department of Orthopaedics and Traumatology, Department of Clinical Research, Odense University Hospital, University of Southern Denmark
Background: Knee joint load is an important factor
associated with progression of knee
osteoarthritis. To provide an overall
understanding of knee joint loading, the
Knee Index (KI) has been developed to
include moments from all three planes
(frontal, sagittal and transversal).
However, before KI is used in clinical
trials a biomechanical analysis
identifying the respective contributions
of the knee moments derived from the
three planes is needed.
Purpose / Aim of Study: The purpose of this study was therefor
to investigate how the frontal, sagittal
and transversal moments contribute to
KI, a novel biomechanical index of joint
load for the knee, in patients with mild
to moderate knee osteoarthritis.
Materials and Methods: The contribution of frontal, sagittal
and transversal plane knee moments to KI
was investigated in 24 subjects (13
women, age: 58 ± 7.6 years, BMI: 27.1 ±
3.0) with clinically diagnosed mild to
moderate knee osteoarthritis according
to the ACR criteria. Three dimensional
gait analysis was performed. Subjects
walked barefoot at self-selected walking
speed. The first peak magnitude KI from
all three planes were calculated using
inverse dynamics.
Findings / Results: Frontal plane kinematics contributed
with 59.3% (SD 25.6) of KI while
sagittal plane kinematics contributed
with 40.5% (SD 26.1). A substantial
inter-subject variation in the relative
contribution of the flexion and
extension moment components to KI was
observed.
Conclusions: Our findings support the notion that the
primary contributor to KI is the frontal
plane kinematics (i.e. the knee
adduction moment), and secondarily the
sagittal plane kinematics (i.e. the knee
flexion moment). This holds promise for
using KI in clinical trials since both
frontal and sagittal knee joint moments
have been suggested to be associated
with the knee osteoarthritis disease
progression.
72. Pelvic movement strategies and leg extension power in patients with end-stage medial knee osteoarthritis: A cross-sectional study
Signe Kierkegaard, Peter Bo Jørgensen, Ulrik Dalgas, Kjeld Søballe, Inger Mechlenburg
Orthopaedic Research, Aarhus University Hospital; Department of Sport Science, Aarhus University
Background: While it is well-known that knee
osteoarthritis (OA) and knee extensor
muscle strength are associated, less is
known about leg extension power
although leg power is closely related to
functional performance in elderly
persons. Patients with medial knee OA
use a variety of compensatory movement
strategies to minimize the joint load in the
affected leg. Little is known about these
movement strategies of the pelvis during
functional performance tests.
Purpose / Aim of Study: The aim of the study was to investigate leg
extension power and pelvic movements
during walking, stair climbing and stepping in
patients with end-stage medial knee OA and
in healthy controls.
Materials and Methods: 57 patients (mean age 65.6 years)
scheduled for medial uni-compartmental knee
arthroplasty (UKA) were included in the
cross-sectional study together with 29 age
and gender matched controls. Leg extension
power was tested in the Nottingham Leg
Extension Power-Rig and pelvic movements
were derived from an inertial sensor with
gyroscope placed between the posterior
superior iliac spines during walking, stair and
step ascending and descending.
Findings / Results: Both the affected and the contralateral leg of
the patients were weaker than the matched
control legs. Patients used a greater pelvic
movement than controls during stair and step
ascending and descending, which was
especially evident during descending.
Furthermore a significant inverse association
between leg extension power and pelvic
movements during stair and step descending
was found in the patient group.
Conclusions: Compared to controls, patients with medial
knee OA use greater pelvic movements
during advanced functional performance
tests, especially during descending tasks.
Further longitudinal studies are required to
investigate pelvic movements after UKA.