HIP
JOINT ANKYLOSIS - COMPENSATION MECHANISMS
by B. Westhoff, R. Krauspe
Higher quality photo images (and photo captions) can be viewed by clicking on the relevant photo thumbnail.
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Figure 1: The gait lab team (left to right): Dr. med. A. Wild, Mrs. I. Kamps, Dr. med. B. Westhoff, Prof. Dr. med. R. Krauspe, M. Hirsch Ph.D. |
In 1999 Prof. Dr. Rüdiger
Krauspe took the helm as Chair of the Department of Orthopedics at Heinrich-Heine
University, Düsseldorf, Germany. Among his areas of expertise, he has a
strong interest in pediatric orthopedics and neuromuscular disorders. For appropriate
analysis of the patterns of gait and movement the installation of a gait analysis
facility was absolutely necessary.
In December 1999 the Vicon 512 system with 6 cameras was ready for a first gait
analysis of a CP-child. The technical equipment includes 2 digital video cameras,
2 AMTI-force plates and a dynamic 8-channel EMG. Actually two further cameras
are installed. The walkway is 12 m in length.
During the first months Dr. Bettina Westhoff, orthopedic staff surgeon in the
Department of Orthopedics, coordinated the set up of the local structure for
the gait laboratory - beside her clinical and operative work. The current team
also includes a technician (Mrs. Kamps) and a physiotherapist (Mrs. Coenen).
Through recent cooperation with the Department of Neurology of the Heinrich-Heine-University
(chairman Prof. Dr. J. Freund) additional personnel support was made available
in the form of Mark Hirsch, who holds a research appointment at the Department
of Neurology (H-H University) and is Assistant Professor of Physical Medicine
and Rehabilitation at the Department of Physical Medicine and Rehabilitation
at Johns Hopkins University, Baltimore, Maryland, USA.
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Figure 2: X-ray of the pelvis (Patrick W., 14yrs) |
The use of 3-D video gait
analysis in our department serves three main purposes: (1) it is introduced
for routine pre-operative screening of functional gait parameters in
CP-patients before lower limb surgery (foot, knee, hip) to confirm or refine
the operative strategy otherwise based on clinical findings and x-ray analysis,
(2) post-operative gait analysis is done routinely to evaluate the outcome,
to control the effect of orthoses and to further advise physiotherapy in detail,
and (3) it is a valuable research tool with broad applications in orthopedic
and neurological patient populations with multiple acute or chronic pathologies
affecting upper and lower limbs.
For scientific research there is special interest in evaluating functional impairment
of hip disorders in children without any underlying neuromuscular disorders
(developmental dysplasia of the hip, Legg-Calvé-Perthes disease, slipped
capital femoral epiphysis etc.). Recently cooperative projects were started
to evaluate neurological patients after strokes and to detail the effects of
Botulinum toxin injections on their gait and movement pattern.
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Figure 3: Kinematics of the left knee joint during barefoot walking (green) and walking with a shoe lift (red) |
A single subject gait analysis
study is presented here to illustrate an example of the lab's activities:
Patrick W. is a 14-year-old male showing a limping, painfree gait, who developed
septic coxitis as an infant and underwent multiple surgeries over the course
of several years. He subsequently developed ankylosis of his left hip. The clinical
evaluation revealed a shortening of 6 cm and a position of the left hip in 20
degrees flexion, 0 degrees abduction and 0 degrees rotation. Radiographic analysis
shows adduction of 4 degrees (Figure 2).
Well documented medium- and long-term sequelae of hip arthrodeses show secundary
ipsilateral knee and lumbar spine degeneration. The objectives of this study
were to (1) quantify the mechanism of how the patient compensates for lack of
hip motion, and (2) to assess the possibilities for improving the pathological
kinetic and kinematic data by balancing the leg length discrepancy. It was hypothesized
that treatment would have a positive effect on the patient's degenerative knee
and spine problems and this would, in turn, be reflected in functionally improved
gait parameters.
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Figure 4A: Kinematics of the left ankle joint during barefoot walking (green)and walking with a shoe lift (red) |
During gait analysis, the
patient walked at a self-selected pace and we compared barefoot walking with
walking with a custom designed orthopedic shoe, which normalized the patient's
leg length discrepancy (6 cm). Toe and heel markers were changed between barefoot
and orthopedic shoe trials. No other markers were changed. Data were averaged
from five trials and these were included in the final analysis.
Results of the time-distance parameters during barefoot walking revealed an
asymmetrical gait with reduced single stance phase on the involved side (right
63,4% + 1,16%; left 51,6% + 1,33%), and a more symmetrical gait pattern reflected
by normalized single stance phase walking with the orthotic shoe (right 58,6%
+ 0,52%; left 58,5% + 0,49%). There was no change in cadence, while stride length
and gait velocity increased with the orthotic shoe fitted.
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Figure 4B: Moments of the left ankle joint during barefoot walking (green) and walking with a shoe lift (red) |
The analysis of the kinematic
data revealed that during barefoot walking there is an increased total range
of motion of the pelvis in the sagittal plane (14 degrees) with increased anteversion
of the pelvis compared to normal and - in spite of a 6 cm leg-length discrepancy
- no increased ROM in the frontal plane. During barefoot walking, the patient
compensated leg-length discrepancy with an equinus foot. In the transverse plane
there was an increased external rotation of the pelvis on the involved side
throughout the gait cycle with maximal external rotation (18 degrees) at the
end of the stance phase.
Balancing of the leg-length discrepancy in this patient produced: (1) no effect
on the ROM of the pelvis in the sagittal and frontal plane; (2) in the transverse
plane the maximum of external rotation of 18 degrees at the involved side persisted
- indicating that this mechanism enables the patient to increase the step length
of the contralateral non-involved side due to an inability to extend the involved
hip. The non-involved hip displayed pronounced enhancement of the ROM
in the sagittal plane (71 degrees), hyperflexion during initial contact and
hyperextension toward the end of stance phase. Wearing an orthotic shoe, maximal
ROM was reduced by 8 degrees, mainly because of reduced flexion during initial
foot contact. In general the enhanced ROM is necessary to increase the step
length of the affected, fused side.
The knee joint on the affected side revealed increased flexion on foot
contact, reduced extension in mid-stance and a reduced maximal flexion in swing
phase compared to normal. Wearing the orthotic shoe demonstrated an interesting
increased flexion throughout stance phase but no knee joint extension during
mid-stance (Figure 3).
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Figure 4C: Powers of the left ankle joint during barefoot walking (green) and walking with a shoe lift (red) |
Kinematic analysis of the
ankle joint movements on the affected side revealed the patient's compensation
mechanisms for leg-length discrepancy with equinus during barefoot walking.
Applying the shoe lift the patient displayed less pronounced ankle plantarflexion.
The double bump pattern of the ankle moment, as well as the substantial power-absorption
during loading response changed toward normal (Figure 4).
The gait analysis clearly revealed that in this patient pathological, compensatory
movement mechanisms due to hip joint stiffness and leg-length discrepancy
(i.e., equinus, time-distance parameters), could partially be improved by shoe
lift for balancing the leg-length discrepancy. Other parameters, such as increased
ROM in the sagittal plane of the pelvis, possibly a major reason for low back
pain, were not affected by equalising the leg-length discrepancy. The data shown
provide an important basis for a more precise definition of the pathologic patterns
and for adequately advising the patient for conservative and / or operative
treatment.
References:
Bennett D, Orr JF, Baker R: Kinematic gait analysis of hip arthrodesis patients.
Gait & Posture 2000, 12, 74
Gore DR, Murray MP, Sepic SB, Gardner GM: Walking patterns of men with unilateal
surgical hip fusion. J Bone Joint Surg 1975, 57A, 759 - 765
Iobst CA, Stanitzski CL: Hip arthrodesis: revisited. J Pediatr Orthop 2001,
21, 130 - 34
Karol LA, Halliday SE, Gourineni P: Gait and function after intra-articular
arthrodesis of the hip in adolescents. J Bone Joint Surg 2000, 82A, 561 - 9
Correspondence address:
Dr. Bettina Westhoff,
Gait Analysis Laboratory
Department of Orthopedic Surgery,
Heinrich - Heine - University,
Moorenstr. 5,
D 40225 Duesseldorf, Germany.
e-mail: westhoff@med.uni-duesseldorf.de