Learning Points

* Define antalgic gait.

* Describe the two responses to pain in a limb that present obstacles to effective walking.

* List some of the common etiologies of antalgic gait.

Antalgic gait refers to a posture or gait assumed in order to avoid or lessen pain. The pain itself can be caused by numerous conditions such as diabetic foot, osteoarthritis, joint or limb deformity, degenerative arthritis of the cervical spine (cervical spondylosis), gout, trauma, rheumatoid arthritis..., etc. The key concept to keep in mind when dealing with antalgic gait is that the patient will try to minimize the amount of weight applied to the painful limb or joint and the amount of time that weight is applied. The result is a limp, a decreased single support time for the affected limb, a shortened stride length for the contralateral limb, and an increased double support time. Antalgic gait is more difficult to recognize if it is bilateral or central. In such cases apprehension of movement may be the only sign visible to the physician.

Excessive tissue tension is the primary cause of musculoskeletal pain (Perry, 176). Common causes of joint distension include trauma (e.g. gross instability or scarring following multi-ligamentous injury) and arthritis. Rapid movement of a pathologic joint increases tissue tension, and therefore, pain. The physiological responses to pain introduce two obstacles to effective walking: deformity and muscular weakness.

Deformity results from the natural resting postures of a swollen joint. The natural resting posture of a swollen joint is the position of minimal intra-articular pressure, where the capsule and ligaments are loosest. Thus, movement in either direction will cause an increase in intra-articular pressure and an increase in the tension of the capsule and ligaments. The minimal pressure postures for the ankle, knee, and hip are as follows: 15° plantar flexion, between 30° to 45° flexion, and 30° flexion respectively. For example, arthritis or other joint pathologies that cause swelling within the hip joint result in a flexed posture while walking in an attempt to keep the hip at minimal intra-articular pressure. The degree of flexion is between 30° to 40° , depending on the extent of the joint pathology. Furthermore, contralateral single limb support time is reduced (i.e. the amount of time the affected leg is in the swing phase) because progression of the limb increases the pressure on the joint capsule, leading to greater pain (Perry, 252).

Muscle weakness occurs secondary to the pain of joint swelling causing reduced activity. Experimentally it has been shown that activation of the quadriceps becomes more difficult when distension of the knee with sterile plasma increased intra-articular pressure. Once the pressure was raised high enough to prevent all muscular activity in the quadriceps, anesthetizing the joint returned full quadriceps activity. This finding indicates that there is a feedback mechanism designed to protect the joint structures from excess pressure. The final effect in the patient is disuse atrophy. During gait analysis, the patient will have less strength and more protective posturing when the joints are swollen.

Arthritis

Primary degenerative arthritis may occur in the hip, knee, ankle, or foot. A history of trauma may be present. Symptoms include morning stiffness and pain with weight bearing and motion of the effected joint. Other findings include joint tenderness to palpation, pain with range of motion, swelling, and crepitance.

Problems at the tarso-metatarsal joint are much more frequent in the elderly due to progressive osteoarthritis at this joint (Spivack, 210). It usually begins and predominates at the first metatarsal medial cuneiform joint. The joint becomes thicker dorsally, medially, and finally, plantarward. It is when the bony prominence reaches the plantar surface that the foot becomes painful on weightbearing.

In the hindfoot, spontaneous osteoarthritis is relatively rare unless there has been prior hindfoot or ankle fracture. A painful hindfoot secondary to congenital deformities and corrective surgery may have secondary osteoarthritis of the subtalar joint and/or ankle. Such a scenerio is often seen with club foot deformities (Spiveck, 212).

Rheumatoid Arthritis

Rheumatoid arthritis always involves the feet, usually bilaterally. With long-standing rheumatoid arthritis, many patients develop bunions, hallux vagus, and hammer toes. With time the metatarsal fat pads atrophy leading to painful anterior metatarsalgia and tender bony metatarsal heads just under the plantar skin. At this stage painless ambulation is not possible and it is necessary to excise the metatarsal heads (the Hoffmann operation).

Gout

Gout is the most common metabolic disorder involving the foot. Gout may result from chronic renal disease or antihypertensive medication. The classical presentation involves the first MTP joint. In acute gout onset is very rapid, often within a few hours, the involved joint swells and becomes very tender to touch and excrutiatingly painful with motion.

Diabetic Foot

Diabetic foot involves small vessel disease, large vessel disease, and peripheral neuropathy. Diabetic foot is more severe and occurs at younger ages in insulin-dependent diabetics. Insulin-dependent diabetics also experience neurovascular and systemic complications earlier. Peripheral neuropathy is a problem because subjective symptoms may be minimized as a result. Peripheral neuropathy often involves numbness or tingling of the feet due to soft tissue (including intrinsic muscles) and fat pad atrophy.

Tendon Rupture

Aside from neurovascular deficiency, tendon pathology is the most disabling foot problem in the elderly (Spivack, 196). Patients with old unrecognized ruptured Achilles tendons, who do not run, have minimal disability. Disorders of the hindfoot are relatively common and are often caused by spontaneous tendon ruptures of the tibialis posterior . This condition can cause plantar or posterior heel pain and when left untreated progresses to a painful flat foot deformity (peritalar dislocation). Spontaneous ruptures of the tibialis anterior tendon often occurs in the sixth or seventh decade. The result is a mild drop foot, which usually does not require surgical repair. A high-top shoe or low boot prevents the foot from dropping further.

Fracture

The effects of fractures are many depending on the bone involved, the location of the fracture on the bone, and the extent of the fracture. The basic priciples of fracture care include acquisition and maintenance of bony alignment, immobilization, and restoration of function. The events following fracture include hemorrhage, edema, tissue necrosis, and inflammation. For 2 to 4 weeks following fracture, weightloading of the bone will not facilitate bony union. Until the bone is healed the patient should walk flat-footed to minimize lower extremity joint movement during weightbearing.

Return to Top

Last Updated: May 15, 1999.
Copyright © 1997-2000 Molson Medical Informatics Project. All Rights Reserved.