INTRODUCTION

Limp is defined as an uneven, jerky, or laborious gait, usually caused by pain, weakness, or deformity [1]. It is a common complaint in childhood, accounting for 4 per 1000 visits in one pediatric emergency department [2]. Limp is caused by benign and life-threatening conditions (table 1), and the management varies from reassurance to major surgery depending upon the cause [2,3].

The cause of limp usually can be determined through a careful history and physical examination. Radiographic studies often are necessary to confirm clinical suspicions, but diagnostic procedures rarely are required. While most cases of limp are caused by trauma or benign self-limiting conditions that resolve spontaneously [4], life- or limb-threatening conditions (table 2) must be diagnosed promptly [5].

An overview of the major causes of limp in children is presented here. The approach to the child with a limp is discussed separately. (See "Approach to the child with a limp".)

INFECTION

Septic arthritis — Septic bacterial arthritis is one of the diagnoses that must not be missed in the evaluation of a child with a limp, given the potential for rapid joint destruction and long-term morbidity with delayed diagnosis. Early diagnosis and treatment are the single most important factors in determining the outcome of septic arthritis. The knee and hip are the joints most commonly affected; involvement of the hip is seen more commonly in infants and young children [6]. In one review of 425 children who were admitted or seen in the emergency department during a 12-month period for a gait disturbance, 14 (3 percent) had septic arthritis [2].

Children with septic arthritis of the hip typically are febrile and ill-appearing, although occasionally the presentation is more subtle [7]. Neonates and infants with septic arthritis of the hip may present with irritability and pseudoparalysis of the affected limb, with or without fever [8-10]. Weightbearing and motion of the affected hip are quite painful and strongly resisted in all patients [11]. Other joints typically are spared, although up to 8 percent of septic arthritis in children is multifocal [12,13]. The presentation of septic arthritis can be altered by recent use of antibiotics.