Lameness

LAMENESS, claudicatio, change in gait due to impaired supporting function of a limb. The supporting function may be impaired for various reasons, such as change in length and shape of the limb, impairment of motor function, or finally the presence of a pain syndrome. L. in the narrow sense of this word, i.e., favoring one leg, is observed with pathological changes in one limb, however disturbances of gait are also noted with a number of deformities affecting both lower limbs. An example can be bilateral congenital dislocation of the hip, in which there is a typical, swaying, so-called duck gait, due on one hand to the absence of sufficient support for the femoral head, and on the other to changes in the normal tone of the gluteal muscles (see Dislocations, congenital). Change in length of the limb, absolute or relative, is observed with various congenital anomalies, such as as in micromelia, partial chondrodystrophy, unilateral congenital dislocation of the hip, etc. Acquired shortening of the limb can result from improperly healed fractures with greater or less displacement of fragments along the length, due to various inflammatory processes leading to destruction of part of the bony skeleton of the limb, or affecting during the period of incomplete growth of the organism the zone of enchondral growth, or finally accompanied by severe trophic disturbances (for example shortening of the limb in epiphyseal osteomyelitis, bone-joint tuberculosis, infantile paralysis, etc.). L., the cause of which is only the difference in length of the limbs, can be easily eliminated by wearing a compensating equalizing insert. In most cases, however, together with the change in length there are also various deformations, usually accompanied by a faulty position of the limb and impairment of function of one or another part of it. Compensation of such a limb only by equalizing it does not eliminate L., since the presence of a faulty position deeply impairs the supporting function. An example can be the flexor-adductor contracture of the hip joint, which occurs with inflammatory, in particular tuberculous, processes in the joint. Besides relative shortening of the limb, significantly exceeding the true shortening, there is asymmetrical standing of the pelvis, increased lumbar lordosis, and often compensatory lateral curvature of the knee joint with formation of genu valgum. Restoration of more normal static relationships is possible only by eliminating this faulty position (conservatively or mostly by operative means). Furthermore, the supporting function of the limb is lost or significantly impaired when the integrity of the skeleton of the limb is impaired, for example in non-union or insufficiently consolidated fractures, false joints, as well as in joint laxity, usually combined with a defect on the part of the ligamentous-muscular apparatus. Impairment of motor function depends either on changes of an articular nature with limitation or loss of mobility in the joints or on lesions of the neuromuscular apparatus. Limitation of mobility in at least one of the large joints of the lower limb affects the dynamics of the entire limb. The patient, adapting to new conditions, modifies the gait, and various mechanical conditions of using one and the other limb during walking determine the difference in supporting and dynamic functions and are manifested practically as L. With lesions of the neuromuscular apparatus, the statics and dynamics of the limb are directly impaired: with widespread paralysis, the function of the limb is completely excluded, with selective lesions there is a specific loss of function and discoordination of muscular traction, often leading to deformities of one or another part of the limb, which significantly increases the disturbance of gait. Various types of paralysis give different types of gait (see Gait). In addition, some types of paralysis (such as infantile paralysis-Heine-Med disease) are accompanied by severe trophic disturbances leading to significant shortening of the limb, as mentioned above. Even with only insufficiency of the muscular apparatus, the patient transfers the main support of his body to the healthy leg, which disrupts normal gait. The instinctive desire to unload the affected limb is also a cause of L. in the presence of a pain syndrome. In some cases, with chronically occurring joint diseases (for example tuberculous), L. is one of the early clinical symptoms and has great diagnostic significance, indicating the presence of a hidden pathological process. Sudden appearance and rapid disappearance of pain in endarteritis causes the so-called intermittent L.-claudicatio intermittens (see). e. Levashova.