Slipped Upper Femoral Epiphysis (SUFE): Causes, Symptoms, Diagnosis, and Treatment

What is SUFE hip?

SUFE, or Slipped Upper Femoral Epiphysis, is a serious orthopedic condition in adolescents where the head of the thigh bone (femoral epiphysis) slips off the neck of the femur at the growth plate, often requiring urgent medical intervention.

Understanding Slipped Upper Femoral Epiphysis (SUFE)

Slipped Upper Femoral Epiphysis (SUFE), sometimes referred to as Slipped Capital Femoral Epiphysis (SCFE), is a condition primarily affecting pre-adolescent and adolescent children, typically during periods of rapid growth. It involves a displacement of the femoral head (the ball of the hip joint) from the femoral neck, occurring through the epiphyseal plate, also known as the growth plate. This slip usually happens posteriorly (backward) and inferiorly (downward) relative to the femoral neck. SUFE is considered an orthopedic emergency due to the potential for severe complications if not promptly diagnosed and treated.

Anatomy Involved

To grasp SUFE, it's essential to understand the anatomy of the proximal femur:

• Femoral Head: The spherical top part of the femur that articulates with the acetabulum (hip socket) to form the hip joint.
• Femoral Neck: The narrow section connecting the femoral head to the shaft of the femur.
• Epiphyseal Plate (Growth Plate): A layer of cartilage near the ends of long bones in growing children. It's where new bone tissue forms, allowing the bone to lengthen. In the proximal femur, this plate is located between the femoral head and the femoral neck. During adolescence, this growth plate is still active and, crucially, is the weakest point of the bone structure, making it susceptible to shear forces that can cause a slip.

In SUFE, the femoral head remains in the hip socket, but the rest of the femur (including the neck and shaft) displaces anteriorly and superiorly relative to the slipped epiphysis.

Causes and Risk Factors

While the exact cause of SUFE is not always clear, it's believed to result from a combination of mechanical stress and inherent weakness of the growth plate. Several factors increase the risk:

• Adolescent Growth Spurts: The most common age for SUFE is during puberty (10-16 years for boys, 8-15 years for girls), when growth plates are rapidly expanding but not yet fully ossified and strengthened.
• Obesity: This is the most significant risk factor. Increased body weight places greater mechanical stress on the hip joint and the vulnerable growth plate.
• Endocrine Disorders: Conditions affecting hormone balance, such as hypothyroidism, growth hormone deficiency, hypogonadism, or panhypopituitarism, can weaken the growth plate. Children with these conditions may develop SUFE at an earlier age or with less typical presentations.
• Trauma: While SUFE can occur acutely after significant trauma, it often develops gradually with minimal or no history of injury, suggesting chronic, repetitive stress as a primary contributor.
• Genetic Predisposition: There may be a familial component, though it's less common.
• Renal Osteodystrophy: Kidney disease can lead to bone abnormalities that weaken growth plates.

Signs and Symptoms

Recognizing the symptoms of SUFE is critical for early diagnosis. The presentation can vary from acute, severe pain to insidious, mild discomfort:

• Hip Pain: This is the most common symptom, though it can be vague. The pain is often felt in the groin, thigh, or, importantly, the knee. Knee pain without a history of direct knee injury should always prompt an evaluation of the hip, especially in an adolescent.
• Limp: The child may develop a noticeable limp, often favoring the affected leg.
• Reduced Range of Motion: Specifically, there is typically a loss of internal rotation and abduction of the hip. As the hip is flexed, the leg often externally rotates automatically.
• External Rotation of the Leg: When walking or standing, the affected leg may appear to be externally rotated.
• Leg Length Discrepancy: In more severe or chronic cases, the affected leg may appear shorter.
• Stiffness: The hip joint may feel stiff, especially after periods of rest.

Diagnosis

Diagnosis of SUFE requires a thorough clinical examination and imaging:

• Physical Examination: The physician will assess gait, range of motion, and palpate for tenderness. The classic finding is limited internal rotation and obligatory external rotation with hip flexion.
• X-rays: This is the primary diagnostic tool. Specific views are crucial:
  • Anteroposterior (AP) view: Shows the hip from the front.
  • Frog-leg lateral view: The leg is flexed at the hip and knee, and the thigh is externally rotated, providing a crucial profile view of the growth plate. This view is often the most revealing for detecting a subtle slip.
• Bilateral Imaging: It is standard practice to image both hips, as there is a significant risk (up to 40-50%) of the condition occurring in the other hip, either simultaneously or at a later time.

Treatment and Management

Treatment for SUFE is almost always surgical and aims to stabilize the slipped epiphysis to prevent further slippage and promote closure of the growth plate.

• Surgical Fixation: The most common procedure is in situ pinning. This involves inserting one or more screws across the growth plate to fix the femoral head to the femoral neck. The goal is to stabilize the slip where it is, rather than attempting to reduce or correct the deformity, to minimize the risk of complications.
• Non-Weight Bearing: Before surgery, the child will be advised to avoid weight-bearing on the affected leg to prevent further slippage.
• Post-Operative Care: After surgery, a period of protected weight-bearing or non-weight-bearing may be required, followed by gradual rehabilitation.
• Addressing Underlying Causes: If an endocrine disorder is identified, it will also need to be managed.

Potential Complications

Despite appropriate treatment, SUFE can lead to several significant complications:

• Avascular Necrosis (AVN) of the Femoral Head: This is a severe complication where the blood supply to the femoral head is disrupted, leading to the death of bone tissue. It can result in collapse of the femoral head and severe arthritis. The risk is higher with unstable slips or attempts at forceful reduction.
• Chondrolysis: Degeneration and destruction of the articular cartilage, leading to joint stiffness and pain.
• Femoroacetabular Impingement (FAI): If the slip results in a bony deformity, it can lead to impingement between the femur and the acetabulum, causing pain and potentially accelerating the development of osteoarthritis.
• Early Osteoarthritis: Long-term, patients with SUFE are at increased risk of developing hip osteoarthritis due to altered biomechanics and potential cartilage damage.

Prognosis and Long-Term Outlook

The prognosis for SUFE is generally good if diagnosed and treated early, before significant slippage or complications occur. Early stabilization prevents further displacement and allows the growth plate to fuse. However, lifelong monitoring may be necessary due to the risk of long-term complications like AVN or FAI, which can lead to premature hip arthritis. The risk of developing SUFE in the contralateral hip also necessitates careful follow-up.

Importance of Early Detection

For fitness professionals, coaches, and parents, understanding SUFE is crucial. Any adolescent presenting with new-onset hip, thigh, or knee pain, especially if accompanied by a limp or changes in gait, warrants immediate medical evaluation. Dismissing knee pain as "growing pains" without a thorough assessment can delay diagnosis and significantly worsen the outcome. Early detection and prompt surgical intervention are paramount to minimize the degree of slippage and prevent devastating complications like avascular necrosis, preserving hip function and joint health.

Conclusion

Slipped Upper Femoral Epiphysis (SUFE) is a critical orthopedic condition of adolescence that demands prompt recognition and treatment. As an expert in exercise science and kinesiology, it's vital to be aware of the signs and symptoms, particularly the often-referred knee pain, to ensure that young individuals receive timely medical attention. Understanding the biomechanical implications and potential long-term complications underscores the importance of a comprehensive approach to adolescent health and musculoskeletal well-being.