The two most common features of the presentation of SCFE are pain and altered gait. The classic presentation is that of an obese adolescent with a complaint of nonradiating, dull, aching pain in the hip, groin, thigh, or knee without a history of trauma. However, 15% of patients present with isolated thigh or knee pain.8 SCFE is more likely to be missed at the initial visit if hip pain is absent or thigh pain is present.
SCFE has traditionally been classified based on intensity and duration of symptoms into four patterns of presentation: pre-slip, acute, acute on chronic, and chronic.
Pre-slips refer to those with pain but without discernable displacement of the epiphysis.
Children with acute slips have symptoms of less than 3 weeks duration. The acute presentation is often associated with trauma. The symptoms are characterized by the onset of severe pain, external rotational deformity and limitation of motion of the hip, shortening, and frequently inability to bear weight. Active motion of the hip is severely limited by muscle spasm, and the patient complains of intense pain with any attempt at passive motion.
The acute on chronic presentation occurs when a patient with an extended history of symptoms, and signs of chronic SCFE presents with an acute increase in pain and loss of motion of the affected hip. Chronic SCFE is the most frequent pattern of presentation and is characterized by vague, intermittent symptoms over a protracted period, generally considered to be longer than 3 weeks.
Patients with chronic SCFE generally have limited any strenuous and sporting activities due to discomfort. They often complain of dull pain often exacerbated by walking or going up stairs and does not resolve quickly with rest. Patients often complain of knee or thigh pain rather than hip pain. On physical examination the patient will usually have altered gait. If a unilateral SCFE is present, the patient will have an antalgic gait (pain on weight bearing of the affected side so that the patient takes a quick, short step on the involved side and a long step on the other side). If bilateral SCFE's are present, the patient will have more of a waddling gait. On inspection, the affected leg is in an externally rotated position and may be shortened. Disuse atrophy of the upper thigh and gluteal muscle may be present. On palpation, there may be tenderness over the hip anteriorly. Despite a complaint of pain to the general area of the knee, there will be no localized tenderness to palpation and the remainder of the knee examination is normal. Range of motion is decreased primarily on internal rotation, abduction, and flexion but may be painful in all directions. The degree of restriction of range of motion is dependent upon the severity of the slip. When the hip is passively flexed from an extended position, the thigh of the affected limb abducts and externally rotates. This finding is very suggestive of SCFE.9
SCFE has also been classified based on biomechanical stability as “stable” or “unstable.”10 A slip is stable if walking and weight-bearing is possible with or without crutches. Unstable slips are those in which the child has such severe pain that walking is not possible even with crutches. Patients with unstable slips may have forewarning symptoms such as vague pain in their hips, thighs, or knees for weeks to even months prior to sustaining an unstable SCFE.11
Lastly, SCFE can be classified by severity and graded as mild, moderate, or severe. A mild slip is one in which the displacement of the epiphysis is less than one-third of the diameter of the femoral neck. A moderate slip is displacement of more than one-third but less than one-half of the diameter of the neck. A severe slip is displacement of more than one-half of the diameter of the neck.