Neurological disorders are often responsible for muscle spasticity and
contractures, which can affect any
joint1-3.
The functional impact can be considerable, altering the quality of life and
the autonomy of these
patients4-7.
Surgical treatment of musculoskeletal complications of cerebral palsy in
children has been the focus of many
studies8-15.
Studies of muscle contractures, particularly flexion contractures of the knee,
in adult patients with neurological disorders are rare. The most common
etiologies of spasticity in adults are traumatic brain injury, stroke,
multiple sclerosis, spinal cord injury, and cerebral
anoxia16. Distal
release of the hamstring tendons followed by immobilization in a cast or brace
has been advocated for
adults16. Compared
with treatment of contractures in children, treatment in adults is more
frequently followed by cutaneous and vascular
complications16,17
as well as by recurrence of the
contracture18.
The purpose of this study was to present our approach for treatment of
flexion contractures in adults, which consists of a distal hamstring release
and femorotibial external fixation when knee extension is limited by excessive
posterior soft-tissue tension. The advantages and disadvantages of this
therapeutic strategy are discussed, and we compare our results with those in
the most relevant series in the literature.
Patients
From 1993 to 2003, forty-seven men and twelve women (ninety-seven knees),
between the ages of twenty-one and seventy-seven years (mean, thirty-six
years), were treated for a flexion contracture of the knee secondary to a
neurological disorder. The causative lesion was a brain injury in twenty-six
patients, a stroke in ten, multiple sclerosis in nine, brain anoxia in six,
cerebral palsy in three, metabolic encephalopathy in three, and brain
abscesses or meningitis in two.
All patients had upper motor neuron lesions. Thirty-two patients had
tetraplegia; eleven, paraplegia; and sixteen, hemiplegia. Eight patients had
severe brain lesions causing a vegetative state. The patients' medical records
were retrospectively reviewed with the approval of our institutional review
board.
The flexion contracture was bilateral in thirty-eight patients. Imaging of
the knee revealed no evidence of neurogenic (Charcot) osteoarthropathy. All
patients were examined while they were under general anesthesia to eliminate
the spastic component of the deformity. Preoperatively, the mean flexion
contracture angle was 69° (range, 20° to 130°) and the mean
passive range of motion was 61° (range, 10° to 110°). In
forty-seven knees, the flexion contracture angle was >90°. The knee
flexion contracture was determined clinically by the same surgeon (P.D.)
preoperatively and postoperatively.
Preoperatively, twenty-four patients were confined to bed and were totally
dependent on nursing care and for sitting and walking (that is, they needed
assistance from one or two persons in order to sit or walk). For these
patients, the surgery was performed to improve nursing care and sitting
posture. Twenty-two patients were partially dependent on nursing care and were
totally dependent for sitting and walking. For these patients, the surgery was
performed to improve sitting posture and walking ability, with the goal of
walking more independently. The thirteen remaining patients were partially
dependent for walking (that is, they needed crutches to walk short distances
and a wheelchair to travel long distances). The goal of the surgery for these
patients was to enhance rehabilitation and improve walking ability. All
patients were enrolled preoperatively in a daily rehabilitation program, which
included strengthening of the quadriceps muscles, stretching of the hamstring
muscles, and knee positioning. Muscle relaxants such as baclofen, diazepam,
and dantrolene were routinely given. Surgery was considered only after
rehabilitation and medical treatment had failed.
A hip flexion contracture was noted in fifty-two patients, and it was
secondary to heterotopic ossification of the hip joint in twenty-one of them.
Thirty patients had bilateral equinovarus foot deformity. Seven patients had a
sacral decubitus ulcer preoperatively. Skin maceration and necrosis of the
posterior aspect of the knee were present in five patients who had severe
flexion contracture (>120°).
Arterial and venous Doppler studies were done in all patients, and
angiography was performed if the result of the Doppler study was abnormal.
Patients with severe arterial lesions (that is, arterial obstruction or
stenosis with residual flow of <50%) were not operated on and therefore
were excluded from the study.
Surgical Procedure
The surgical procedure was performed eight months to thirteen years (mean,
three years) after the onset of the neurological disorder. When a patient had
a hip flexion contracture or an equinovarus foot deformity, the treatment
included surgical correction of those associated deformities.
The knee flexion contracture was corrected through medial and lateral
approaches. The skin incisions were made more anterior than the course of the
tendon because excessive traction forces applied directly on a posterior scar
with knee extension can cause skin necrosis postoperatively
(Fig. 1).
In the lateral approach, the posterior half of the iliotibial tract was
divided and the biceps femoris tendon was z-lengthened. In the medial
approach, the distal parts of the sartorius, gracilis, and semitendinosus
tendons were sectioned and the semimembranosus tendon was z-lengthened.
A posterior capsulotomy was performed in thirty-five knees. The posterior
cruciate and collateral ligaments were left intact. Neurolysis of the peroneal
nerve was performed when there was excessive tension in extension.
Complete extension of thirty-four knees was achieved intraoperatively.
Complete intraoperative correction of the flexion contracture was not possible
in the remaining forty-four knees because of excessive skin and neurovascular
tension, as subjectively determined by the surgeon (P.D.). The residual
flexion contracture ranged from 10° to 30° in thirty-three knees and
was >30° in eleven.
A splint was used to maintain the correction in twenty knees in which the
preoperative flexion contracture had been <40° and had been completely
corrected intraoperatively. A unilateral external fixator (Orthofix, Gentilly,
France), consisting of two lateral femoral pins and two anterior tibial pins
connected by a single rod, was used to maintain the correction in
seventy-seven knees. A joining rod connecting both external fixators was used
for patients with a bilateral contracture. The lower limbs were positioned to
avoid cutaneous pressure sores.
Mobilization of the contractures was started on the day after the
operation. It consisted of passive and active mobilization
(Fig. 2), after removal of the
external fixator rod, performed four times daily. This was followed by
alternation of flexion and extension postures maintained by means of the
external fixator after the rod was reconnected. Initially, 10° of flexion
was maintained between the sessions to avoid cutaneous or neurovascular
problems. This degree of flexion was progressively diminished by mobilization
to obtain complete extension of the knee before the external fixator was
removed. The external fixator was removed at a mean of forty-two days (range,
thirty to seventy-five days) after the surgical procedure. Then a splint, with
the knee in extension, was used for one month.
The algorithm for our surgical strategy is summarized in
Figure 3.
The mean follow-up period was two years (range, one to five years). Three
patients (two who were treated postoperatively with splints only and one who
was treated with an external fixator) died during the follow-up period. The
mean residual flexion contracture was 6.2° (range, 0° to 40°).
Forty-five knees had complete extension, thirty-nine knees had a residual
flexion contracture of <10°, seven knees had a residual contracture
ranging from 10° to 25°, and six knees had a residual contracture
ranging from 26° to 40°. Two patients who had been able to walk
preoperatively, and had been treated with hamstring lengthening, mobilization,
and splints, could not walk postoperatively because of a residual flexion
contracture of 30°. Both underwent mobilization while under general
anesthesia followed by immobilization in serial long-leg casts. Both patients
had a satisfactory result and regained the ability to walk. One patient had a
residual flexion contracture of 10°, and the other had a residual
contracture of 15°.
Twenty-nine (30%) of the ninety-seven knees had a decrease in flexion, from
a mean of 130° preoperatively to a mean of 118° at the time of final
follow-up. However, the overall range of motion was improved in all patients,
to a mean of 111° (range, 85° to 145°). No recurrence of the
flexion contracture or knee instability was noted at the time of follow-up. In
one patient who had presented with quadriceps spasticity, knee recurvatum
progressed to 5° more than that seen one year postoperatively.
We noted seven postoperative complications but no neurovascular
complications. Three patients had cutaneous ulcerations, which were
successfully treated with local débridement. In a fourth patient, a
gastrocnemius muscle flap was necessary to achieve wound-healing. Three
patients had a low-grade infection around external fixator pins, which
resolved after removal of the external fixator and administration of
antibiotics.
At the time of final follow-up, thirteen patients were able to walk without
assistance, and twenty-four patients were able to walk with assistive devices.
Five patients benefited from the procedure in that it enabled them to maintain
a standing posture, and five benefited in that it enabled them to obtain a
comfortable posture for sitting. The only benefit for twelve patients was an
improvement in nursing care and hygiene. A comparison between the preoperative
and follow-up angular and functional results is shown in
Table I.
Perhaps the last major paper on knee flexion contracture in spastic adults
was written by Keenan et
al.16 and published
in 1988. This long lag period could be explained by a lack of interest among
orthopaedic surgeons in the treatment of spasticity in adults. However, hip
and knee flexion contractures are common in spastic
adults19, and an
increase in survival rates among patients with central nervous system injury
or cerebral palsy has resulted in a growing number of adult
patients16 with
this condition.
For neurologically impaired patients with knee flexion contractures who
have the potential for walking, the goal of surgery is to improve walking
ability. For patients with severe deformities, especially those with severe
neurological impairment who cannot walk, the aim of surgery is to improve
comfort, nursing care, and hygiene. For fifteen patients in our
series, the surgery made nursing care easier and enabled them to use a
wheelchair, with resultant improvement in their self-image. For thirty
patients, the extension of the knee achieved by the surgery made an upright
position possible and improved walking ability. The surgical objectives were
limited for some of our patients because of their underlying neurological
status and degree of knee flexion contracture. The best results were obtained
for patients who had a brain injury with residual lower-limb spasticity
following recovery of good upper-extremity function.
Nonoperative methods of treatment, including
physiotherapy7,
postural exercises4,
and serial
casts20,21,
have been proposed for the correction of knee flexion contractures. Surgical
treatment consisting of proximal hamstring release in children has been
described by many
authors11,22,23.
Proximal and distal releases of the hamstring tendons have been found to be
useful alternative procedures, but they should be done only in patients who
cannot walk because proximal hamstring release may result in pelvic
anteversion, lumbar hyperlordosis, and subsequent hip flexion contracture in
ambulatory
patients14.
Distal hamstring release, often associated with posterior capsulotomy, is
the most common method described in the literature for the treatment of knee
flexion contracture in adult
patients8,16,18,24-26.
Minor flexion deformity of the knee in adults can be treated with
supracondylar
osteotomy27-29.
We used the surgical technique described by Keenan et
al.16 for
soft-tissue release; however, we added a posterior capsulotomy of the knee
joint in thirty-five patients. We did not remove the posterior cruciate
ligament or the posterior parts of the collateral ligaments to avoid
postoperative knee instability and posterior subluxation of the tibia.
We found the use of an external fixator to be preferable to serial splints
or casts for patients with a residual knee flexion contracture after
soft-tissue release. As occurred in the study by Herzenberg et
al.30, there were
minor infections around some pins in our series. Fractures and peroneal nerve
palsy have been described after progressive correction of knee flexion
contractures with the Ilizarov
technique10. In our
series, the use of a simple external fixator device maintained the knee
extension achieved during the daily manipulations postoperatively. The
deformity correction was progressive after soft-tissue release and permitted
optimal postoperative physiotherapy and skin management. However, because of
the potential for cutaneous, nerve, or vascular problems in patients with
severe knee flexion contractures, we stress the importance of a very slight,
progressive increase in the mobilization force applied daily to the knee joint
and soft tissues. We treated two patients with a severe flexion contracture
with serial casts after removal of the external fixator.
Preoperatively, we performed a systematic vascular evaluation with arterial
and venous Doppler studies of both lower limbs for all patients, and we
excluded patients with poor arterial or venous flow, who were at high risk for
vascular complications.
Progressive recurvatum developed in one patient with quadriceps spasticity.
This was previously described by Herzenberg et
al.30 after
excessive hamstring lengthening, and one should be aware of the possibility of
progressive genu recurvatum in patients with quadriceps spasticity. If
complete extension of such a knee is easily obtained, a plaster splint should
be used to avoid excessive correction of the knee flexion contracture during
the first few months following the surgery.
Our clinical experience is consistent with that of Keenan et
al.16, in that
eighteen months following the onset of the neurological disorder appears to be
the optimal time for the correction of such deformity. We consider surgical
treatment only after rehabilitation and medical treatment have failed. We
agree with many
authors2,14,23,31
that treating all lower-extremity deformities with a single surgical approach
provides better functional results for these patients. We stress the
importance of a rehabilitation program during and after the period of internal
fixation. We believe that this is the main reason why none of the flexion
contractures had recurred at the time of follow-up. ?