progressively more intense cervical traction treatment, depending on severity of symptoms and neurological findings. Subjects received traction treatment at home, in an outpatient facility, or in the hospital. The percentage of patients with excellent or good outcomes was 92% in the home treatment category, 77% in the outpatient treatment category, and 65% in the hospital treatment category.
6. Is cervical traction effective for treatment of cervicogenic headache?
No clinical trials have been performed using cervical traction to treat cervicogenic headache, but two case studies suggest that cervicogenic headache can be treated successfully with traction. Using 25- to 30-lb home traction and cervical exercise, Olson reported success with two difficult cases of headache caused by chronic whiplash. The cervical exercise consisted of postural correction and stabilization exercises.
7. What are the important treatment variables for cervical traction?
• Chin halter versus occipital wedges—When traction is provided with a standard head halter with a chin strap, force is transmitted through the chin strap to the teeth, and the temporo- mandibular joints become weight-bearing structures. A common problem from administering cervical traction is aggravation of the temporomandibular joints because of the force applied at the chin. It is generally advisable to use a cervical traction system that pulls from the occiput, rather than placing pressure on the chin. If the patient has known temporomandibular dysfunction, a chin halter should never be used.
• Force—To effectively treat cervical radiculopathy, herniated disk, or other conditions requiring a separation of the intervertebral space, the traction force should be great enough to cause movement at the spinal segment. Based on our experience and the evidence available in the literature, we typically use a force of 25 to 40 lb for the midcervical and lower cervical spine. Less force is necessary when treatment is directed to the upper cervical area.
• Patient position—We recommend the supine position to facilitate patient relaxation, proper force application, and optimal cervical angle. The supine position is favored in the literature.
Cervical traction studies show that narrowingof the intervertebral spaces can actually occur during the traction treatment in patients who are unable to relax.
• Cervical angle—Cervical traction is performed with the head and neck in some degree of flexion. Some clinicians believe that the greater the angle of flexion, the greater the intervertebral separation in the lower cervical spine. While it is true that posterior separation does increase with more flexion, anterior separation decreaseswith flexion. In most cases, clinicians should try to achieve a combination of a posterior and anterior stretch. Thus the ideal traction device will flex the head and neck somewhat, but pull at a relatively flat angle. We recommend a 15-degree angle to accomplish this goal.
• Mode (static or intermittent)—The traction mode selected will depend on the disorder being treated and the comfort of the patient. Herniated disk is usually treated more effectively in static mode or with longer hold-rest periods (3- to 5-minute hold, 1-minute rest) in intermittent mode. Joint dysfunction and degenerative disk disease usually respond to shorter hold-rest periods (1- to 2-minute hold, 30-second rest) in intermittent mode.
• Time—When treating herniated disk, the treatment time should be relatively short. As the disk space widens, the intradiskal pressure decreases, causing the herniated disk material to be retracted into the disk space. The decrease in pressure is temporary, however, because eventually the decreased intradiskal pressure will cause fluid to be imbibed into the disk. When pressure equalization occurs, the suction effect on the disk protrusion is lost, and it is possible for patients to experience a sudden increase in pain when traction is released. If the traction time is 8 to 10 minutes, this effect is minimized. For other conditions, a treatment time of up to 20 minutes is often used. As a general rule, the higher the force, the shorter the treatment time. Often the first treatment is only 3 to 5 minutes long. This gives the clinician a chance to determine the patient’s reaction to treatment and plan treatment progression accordingly.
There is consensus in the literature that a force of 40% to 50% of the patient’s body weight is necessary to cause vertebral separation. In one of the earliest lumbar traction studies, Cyriax reported a visible separation between lumbar vertebrae with static traction of 120 lb for 15 minutes. Other studies have reported measurable separation in the lumbar spine at forces ranging from 80 to 200 lb. Judovich advocated a force equal to one half the patient’s body weight on a friction-free surface as the minimum force necessary to cause therapeutic effects in the lumbar spine.
9. Is lumbar traction effective for lumbar radiculopathy?
Epidurography and CT investigations have shown that high-force traction can reduce disk protrusions and relieve spinal nerve root compression symptoms. Despite these findings, lumbar traction is currently out of favor in the literature. Four reviews summarizing lumbar traction studies have concluded that there is no significant benefit for patients treated with lumbar traction compared to a control group. However, wide variations of methods and techniques were described in the studies cited. Some of the studies that showed lumbar traction was ineffective were performed with low forces. In many of the studies, patient selection criteria were poorly defined.
Most studies tended to group all patients with low back pain together and did not distinguish between subgroups or by diagnosis. The only two studies that looked specifically at traction for herniated disk did not use forces generally considered sufficient to separate the intervertebral spaces.
10. What are the most important treatment variables for lumbar traction?
• Force—To effectively treat lumbar radiculopathy, herniated disk, or other conditions requiring a separation of the intervertebral space, the traction force should be great enough to cause movement at the spinal segment. Based on our experience and the evidence available in the literature, we typically use a force of 40% to 50% of the patient’s ideal body weight. Often the first treatment is a little less to ensure patient tolerance.
• Spinal position—The position of the spine during traction is an important treatment variable.
In our experience, disk herniation is most effectively treated with the patient lying prone with a normal lordosis. However, this position is not always possible because the patient with acute herniated disk may not tolerate any position of normal lordosis. If this is the case, the treatment must be given in flexion initially with the goal of gradually working toward neutral lumbar lordosis. Foraminal (lateral) stenosis is usually more effectively treated with the lumbar spine in a flexed (flattened) position initially, with the goal of achieving a neutral lordosis when possible.
Soft tissue stiffness/hypomobility and degenerative disk or joint disease may be treated in neutral position or some degree of flexion or extension, depending on the goals of treatment.
Patient comfort and the patient’s ability to remain relaxed during the treatment are important considerations when choosing the most beneficial position, and no absolute rule applies.
Variations of flexion, extension, and lateral bending should be tried to find the most beneficial position for each patient.
• Mode (static or intermittent) and time—See question 7.
11. Does spinal traction change somatosensory evoked potentials (SSEPs)?
SSEP latencies were decreased after cervical traction in patients with radiculopathy and cervical sprain. In patients with severe myelopathy, latencies may increase. Traction may improve conduction by improving blood flow to cervical nerve roots.
Bibiolography
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1. What is the average adult walking velocity?
• On level surfaces, approximately 80 m/min
• In men, 82 m/min
• In women, 79 m/min
2. Does walking velocity decline with age?
Yes. Declines of 3% to 11% in healthy adults >60 years old have been reported.
3. Name contributors to an individual’s walking velocity.
• Step (or stride) length
• Cadence
4. What is considered normal stride and step length?
• Stride length is the distance from ipsilateral heel contact to the next ipsilateral heel contact during gait (i.e., right-to-right or left-to-left heel contact). Normal adult stride length averages approximately 1.39 m, with the mean stride length of men (1.48 m) being slightly longer than that of women (1.32 m).
• Step length is the distance between ipsilateral and contralateral heel contact (e.g., right-to-left heel contact) and is on average equal to half of stride length.
5. What is normal cadence?
Cadence is the number of steps per minute.
• In adults without pathology, average 116 steps/min
• In women, 121 steps/min
• In men, 111 steps/min 6. Define gait cycle.
Gait cycle is a repetitive pattern that extends from heel contact to the next episode of heel contact of the same foot. The gait cycle can be further subdivided into a period of stance, when the limb is in contact with the ground (approximately 60% of the gait cycle), and a period of swing, when the limb is not in contact with the ground (approximately 40% of the gait cycle).
7. Describe the functional tasks associated with normal gait.
Functionally, each gait cycle can be divided into three tasks:
1. Weight acceptance 2. Single limb support 3. Swing limb advancement
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Normal and Pathologic Gait
Judith M. Burnfield, PT, PhD, and Christopher M. Powers, PT, PhD
During weight acceptance, body weight is accepted onto the limb that has just completed swinging forward. The limb must absorb shock arising from the abrupt transfer of body weight, while remaining stable and allowing continued forward progression of the body.
During single limb support, only the stance limb is in contact with the ground, and the limb must remain stable while allowing continued forward progression of the body over the foot.
Swing limb advancement includes the phase when weight is being transferred from the reference limb to the opposite limb as well as the entire reference limb swing period. During swing limb advancement, the foot must clear the ground to ensure forward progression.
8. Describe the key motions and muscular activity patterns at the ankle, knee, and hip during weight acceptance.
At the beginning of weight acceptance, the ankle is positioned in neutral, the knee observationally appears to be fully extended (it is actually in 5 degrees of flexion), and the hip is flexed approxi- mately 20 degrees (relative to vertical) in the sagittal plane. These combined joint positions allow the heel to be the first part of the foot to contact the ground. During weight acceptance, as the foot positions itself flat on the ground, the ankle moves into 5 degrees of plantar flexion, controlled by eccentric activity of the dorsiflexors. The knee moves into 15 degrees of flexion, controlled by eccentric activity of the quadriceps. The hip remains in 20 degrees of flexion, primarily owing to isometric activity of the single joint hip extensors.
9. Describe the key motions and muscular activity patterns at the ankle, knee, and hip during single limb support.
Movement of the ankle from 5 degrees of plantar flexion to 10 degrees of dorsiflexion is controlled by eccentric activity of the calf. The knee moves from 15 degrees of flexion to what observationally appears to be full extension (actually 5 degrees of flexion by motion analysis), in part as a result of concentric activity of the quadriceps (early single limb support) in combination with passive stability achieved when the ground reaction force vector moves anterior to the knee joint (late single limb support). The hip moves from 20 degrees of flexion to 20 degrees of apparent hyper- extension (a combination of full hip extension, anterior pelvic tilt, and backward pelvic rotation), in part as a result of concentric activity of the single joint hip extensors (early single limb support) in combination with passive stability achieved when the ground reaction force vector moves posterior to the hip joint.
10. Describe the key motions and muscular activity patterns at the ankle, knee, and hip during swing limb advancement.
Initially, as the more proximal joints begin to flex, the foot remains in contact with the ground and the ankle moves passively into a position of 15 degrees of plantar flexion. Once the foot lifts from the ground, the ankle moves to neutral dorsiflexion owing to concentric activity of the pretibial muscles. The knee initially moves into 40 degrees of flexion (while the foot is still on the ground) primarily as a result of passive forces. As the foot is lifted from the ground, the knee moves into 60 degrees of flexion, owing to concentric activity of knee flexors (biceps femoris short head, gracilis, and sartorius). During late swing limb advancement, the knee fully extends, in part as a result of momentum and quadriceps activity. The hip moves from 20 degrees of apparent hyperextension to 25 degrees of flexion by the middle of swing because of a combination of hip flexor muscle activity and momentum. In late swing, hip flexion decreases to 20 degrees as the hamstrings decelerate further progression of the leg.
11. What factors contribute to shock absorption during weight acceptance?
• Eccentrically controlled knee flexion to 15 degrees allows for dissipation of forces generated by the abrupt transfer of body weight onto the limb.
surfaces. The rate of this motion is controlled by eccentric activity of the tibialis anterior and posterior.
12. What allows for stance stability during single limb support?
• Stability arises primarily from the action of the calf muscles that restrain excess forward collapse of the tibia. As a result, the knee and hip are able to achieve a fully extended position with only minimal muscle activity requirements.
• In late single limb support, a reduction in the amount of subtalar joint eversion functions to lock the midtarsal joints and creates a rigid forefoot over which body weight can progress.
13. What allows for foot clearance during swing limb advancement?
• Early in swing limb advancement, knee flexion to 60 degrees (owing to passive and active factors) assists in clearing the limb.
• As swing limb advancement progresses, hip flexion to 25 degrees, in combination with ankle dorsiflexion to neutral, becomes critical to achieve foot clearance.
14. Name key factors that are essential to ensure forward progression during the gait cycle.
• Forward progression during weight acceptance results primarily from eccentric activity of the dorsiflexors, which not only lower the foot to the ground but also draw the tibia forward.
• During single limb support, controlled tibial progression resulting from eccentric calf activity allows forward progression without tibial collapse.
• The 20 degrees of apparent hyperextension achieved at the hip contributes to a trailing limb posture that increases step length and forward progression.
• During swing limb advancement, knee extension and hip flexion to 20 degrees in late swing contribute to forward progression and step length.
15. Describe the role of the heel, ankle, and forefoot “rockers” during gait.
Collectively, the three rockers reflect a combination of joint motions and muscle actions that contribute to the smooth transition of body weight from the heel to the forefoot during stance.
The heel rocker occurs during weight acceptance. Eccentric activity of the pretibial muscles lowers the forefoot to the ground and draws the tibia forward, allowing body weight to roll across the heel.
Next is the ankle rocker, occurring during the first half of single limb support. The ankle moves from 5 degrees of plantar flexion to slight dorsiflexion. A gradual increase in eccentric calf muscle activity allows the tibia to remain stable as body weight progresses in front of the ankle. The forefoot rocker occurs during the last half of single limb support. A modulated increase in eccentric calf muscle activity permits the ankle to move into 10 degrees of dorsiflexion (without collapsing) and the heel to rise. Body weight smoothly transitions across the forefoot.
16. What is the functional significance of normal subtalar joint eversion/inversion during the stance phase of gait?
During weight acceptance, subtalar eversion is important for unlocking the midtarsal joints (calcaneocuboid and talonavicular) and creating a more flexible foot that is able to adapt to uneven surfaces. During single limb support, a reduction in the amount of subtalar eversion (motion toward inversion) functions to lock the midtarsal joints, creating a rigid forefoot lever over which the body weight can progress.
17. What effects would a weak tibialis anterior have on gait?
• Foot slap immediately after initial contact (lack of eccentric control)
• Footdrop during swing
• Excessive hip and knee flexion (steppage gait) to clear the toes during swing
18. Describe gait deviations that likely would be evident in a patient with plantar fasciitis or a heel spur.
Patients typically exhibit a forefoot initial contact, avoiding the pressure associated with heel impact during weight acceptance. As the plantar fascia becomes tight with the combination of heel rise and metatarsal-phalangeal joint dorsiflexion during late stance, patients may avoid this posture by prematurely unweighting the limb.
19. What are the consequences of a triple arthrodesis on gait function?
• Loss of subtalar joint motion results in reduced shock absorption during weight acceptance.
• The inability to supinate in terminal stance diminishes the forefoot rocker effect.
• The ability to progress beyond the supporting foot is compromised.
• Stride length is diminished.
20. Describe the effect of calf weakness on ankle function during gait.
Calf weakness results in the inability to control forward advancement of the tibia, causing excessive dorsiflexion during single limb support and a lack of heel rise during late stance. As a result of the inability to control the tibia through eccentric action, the tibia advances faster than the femur, causing knee flexion during stance. The flexed knee posture necessitates activity of the quadriceps, which normally are quiescent during single limb support.
21. Describe the effect of a plantar flexion contracture on ankle function during gait.
A plantar flexion contracture (>15 degrees) results in either a flat-foot or a forefoot-initial contact.
This disrupts normal advancement of the tibia and may limit the knee from flexing to dissipate the forces associated with weight acceptance. During single limb support, the primary limitation is the inability to progress over the foot. Because 10 to 15 degrees of ankle dorsiflexion is necessary for normal stance phase function, compensatory mechanisms are necessary. Progression may be augmented through a premature heel rise, forward trunk lean, knee hyperextension, or a combination thereof. The inability to achieve a neutral ankle position during swing also necessitates compensatory movements to ensure foot clearance.
22. What are the characteristics of quadriceps avoidance?
Quandriceps avoidance manifests as reduced knee flexion during weight acceptance. This compensatory strategy results in decreased quadriceps demand and diminished muscular forces acting across the knee.
23. With what orthopaedic conditions could quadriceps avoidance be associated?
• Patellofemoral pain
• Anterior cruciate ligament deficiency
• Quadriceps weakness
• Quadriceps inhibition (owing to pain or effusion)
24. Discuss the penalty associated with a knee flexion contracture.
A knee flexion contracture (>15 degrees) results in excessive knee flexion during weight acceptance, during single limb support, and at the end of swing limb advancement. The penalties include