GAIT TRAINING AND KNEE HYPEREXTENSION P Teran-Yengle1, NA Segal2, NF Johnston1, B Singh1, JC Torner3, R Walace3, HJ Yack1 1 Program in Physical Therapy & Rehabilitation Science 2 Department of Orthopaedics & Rehabilitation 3 School of Public Health The University of Iowa Email:
[email protected] INTRODUCTION The health of articular cartilage is associated with appropriate stress occurring in appropriate regions (2). In the knee, abnormal arthokinematics can result in abnormal loading patterns that can potentially be detrimental to the integrity of the cartilage resulting in osteoarthritic changes (3). While knee hyperextension has been linked to a number of neuromuscular pathologies, the connection with osteoarthritis is less clear, but clinically evident (1). It is unclear if hyperextension contributes to the initiation of knee OA or if it evolves from compensatory strategies adapted by the patient. Changing gait kinematics in order to correct for knee hyperextension is generally viewed as an appropriate goal when working with patients who have knee OA. The methods to accomplish this have typically been limited to taping, bracing, and/or muscle strengthening and have had only limited success. The purpose of this study was to investigate the use of gait training with real-time biofeedback in controlling knee hyperextension. This initial report provides data on three subjects who were part of a larger project studying interventions with knee OA patients. METHODS One female and two male patients with diagnosis of bilateral knee osteoarthritis underwent the gait training for correction of knee hyperextension. Knee hyperextension on these individuals was documented during their initial over-ground gait evaluation. The gait evaluation was conducted along an 8 m walkway using a three-dimensional motion analysis system (Optotrak, NDI; Kistler) with subjects walking at 1.12 m/s. Gait data were processed using Visual 3D software (C-Motion). The gait information in combination with the
physical evaluation information was used to establish goals during gait training. Subjects participated in supervised treadmill gait training twice a week for 12 weeks. Subjects walked on an instrumented treadmill (Gaitway, Kistler) at self selected walking speeds for 8 minute intervals with 3 to 5 minute rest periods. During the gait training, the subjects were provided with realtime biofeedback (Visual 3D) for correction of kinematic patterns representing knee hyperextension. Gait and physical evaluation were reassessed during the 8th, 16th, and 24th visits. The objective with our participants was to progressively introduce real-time biofeedback to reduce and control knee hyperextension. First, the general body movement was shown using the skeleton model. Subjects then transitioned to using a running representation of their knee sagittal plane angle (Figure 1). Feedback was also provided during rest periods to reinforce corrected patterns over ground walking.
Figure 1: Example of single plane kinematic feedback used to provide subjects information on the position of their knee. Yellow area represents target region which was set at 5 degrees of knee flexion.
RESULTS & DISCUSSION All three subjects responded positively to the gait training and showed improved control of knee hyperextension. Figure 2 shows ensemble of knee sagital plane range of motion for participant #3 for one gait cycle. The changes in range of motion for the knee in the sagittal plane are presented in Table 1. This table shows the improvements at the heel contact and forward progression of the involved knee for each subject.
subject demonstrated ability to carry over corrected gait patterns without visual feedback and referred improved awareness in knee alignment when standing and pain reduction at night. In regards to participant #11, she showed reduction of knee hyperextension at both heel contact and push off (Table 1), and reduction of knee adduction moment on both knees. Participant also referred improved ability to stand for longer periods of time without pain on either knee.
Knee Kinematics: Sagittal Plane Movement Participant #3
The gait training addressed modifications during the heel contact and forward progression to develop confidence in the stance-phase controlling for pelvic rotation, hip extension, and dorsiflexion range.
Right
Left
CONCLUSIONS The gait training showed that knee sagittal plane kinematics can be influenced with dynamic gait training using real-time biofeedback.
Figure 2: Example gait data showing ensemble averaged of knee sagittal plane range of motion for one gait cycle (toe-off to toe-off). Blue (Baseline); Red (After 1st month); Purple (after 2nd month) of gait training
At the initial evaluation, participant #3 showed 1.36 and 4.92 degrees of left knee hyperextension at heel contact and forward progression, respectively. After three months of training, the hyperextension was reduced to 0.88 and 2.05 degrees. Participant #10 showed reduction of left knee extension at the push off. This reduction was achieved along with a more stable pelvis during weight transfer. This particular Knee Joint Angle (deg)
REFERENCES 1.Fish D, Kosta Ch. Genu Recurvatum: Identification of Three Distinct Mechanical Profiles. Journal of Prosthetics & Orthotics 10(2):26-32, 1998. 2.Maly M. Abnormal and Cumulative Loading in Knee Osteoarthritis. Current Opininion in Rheumatology, 2008. 3.Andriacchi TP, Koo S, Scanlan S. Gait Mechanics Influence Healthy Cartilage Morphology and Osteoarthritis of the Knee. J Bone Joint Surg Am. 91:95-101, 2009. ACKNOWLEDGEMENTS This research was supported by the Beeson Career Development Award in Aging Program (NIH/NIA 1K23AG030945)
Pre Training HC
Post Training PO
HC
PO
Participant #3 (Left Knee)
1.36
4.92
0.88
2.05
Participant #10 (Left Knee)
1.28
5.65
4.80
-1.80
Participant #11 (Right Knee)
2.86
2.05
1.25
-0.46
Table 1: Involved knee join angles at heel contact (HC) and push off (PO) pre and post gait training
