1st Joint ESMAC-GCMAS Meeting - Análise de Marcha

O-38
BIOMECHANICAL AND METABOLIC PERFORMANCE OF A NEW ORTHOTIC
KNEE JOINT PRINCIPLE FOR STANCE PHASE SAFETY
Schmalz, T., PhD 1 , Blumentritt, S., PhD 1 , Drewitz, H., CPO 2
1 Department of Research, Otto Bock Health Care, Duderstadt, Germany
2 Orthopaedic Workshop, Rehabilitation Centre, Göttingen, Germany
Summary
Recently developed orthotic knee joints that are integrated into a knee-ankle-foot-orthosis
(KAFO) stabilize the paralyzed knee in stance phase while permitting natural flexion and
extension at the knee during swing phase. The functional advantages for these patients can be
documented by metabolic and biomechanical parameters.
Introduction
For many patients with lower limb weakness or paralysis, functional mobility is achieved by
means of a KAFO. In traditional orthoses, the knee joint is locked throughout the complete gait
cycle (knee completely locked – KTL) to guarantee safety during stance phase. Over the last
few years, 5 new orthotic systems ([1]) have been developed worldwide which stabilize the
knee joint during stance phase without interfering with knee flexion in swing (knee locked
during stance – KLDS). In the present study, KAFOs utilizing KTL and KLDS principles are
compared based on metabolic and biomechanical parameters.
Statement of clinical significance
This study investigates and documents the functional advantages that patients with lower limb
weakness or paralysis can anticipate from orthoses utilizing the new KLDS principles.
Methods
6 patients (5 male patients and 1 female patient, aged 48±14y, height 177±9cm, body mass 83
±14kg) with paresis of the m.quadr. fem. who had been fitted with a KAFO (Free Walk, Otto
Bock, Germany) were examined. The knee joint in this orthosis can be used in either KTL and
KLDS settings. Metabolic energy consumption was measured while walking on a treadmill
(velocities between 0.6 and 0.95m/s) using the CPX system (MedGraphics, USA). Kinematic
and kinetic parameters determined while walking on level ground at each subject’s selfselected
comfortable speed (VICON 460, Oxford Metrics, GB; Kistler Force Plates, Kistler
AG, Switzerland). A similar gait analysis on level ground was conducted with a group of
healthy people (n=30, age 28±5y, height 175±6cm, body mass 71±9kg) for comparison.
Results
Using the KLDS principle on a treadmill, a significant reduction of oxygen consumption
averaging 12% was demonstrated. Average heart rate also dropped significantly by 7% (table
1). Biomechanical gait parameters demonstrated that the abnormal pelvic obliquity, necessary
to clear the foot when the KAFO was in the KTL mode, is eliminated in the KLDS mode.
(Figure1, left). Furthermore, the distinct overload on the joints of the contralateral leg, which
was present in KTL mode, is significantly reduced in the KLDS situation. (reduction of strong
external extension moments in knee and hip joint, figure 1, right).
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