DOS Kongressen 2014 ·
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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 ex-
tensor muscle strength are associated, less is known about leg extension power
although leg power is closely related to functional performance in elderly per-
sons. 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 exten-
sion 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 exten-
sion power was tested in the Nottingham Leg Extension Power-Rig and pelvic
movements were derived from an inertial sensor with gyroscope placed be-
tween 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 as-
sociation 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.
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