Cite This Article

Woodruff R, Tomesch A. A Real Kick in the Hip. Ortho Pearls. June 5, 2024; Available: https://www.orthoempearls.com/articles/a-real-kick-in-the-hip

What is your diagnosis?

Legg-Calve-Perthes (LCP) disease

• Pearl: LCP is a disease of the hip caused by avascular necrosis of the femoral head. Early stages of LCP are often not identifiable on X-ray and will only be detected by MRI, however as the disease progresses X-ray imaging can be useful [1]. In late stages x-ray will show joint space widening, increased lucency of the femoral head, and flattening and fragmentation of the femoral head (red dotted line, image 2).

Image 2. Annotations by Author. Case courtesy of Bruno Di Muzio, Radiopaedia.org, rID: 12153

What pathological injury can cause this finding? How can you rule it out?

LCP is associated with multiple risk factors that can predispose one to developing the disease, the most common risk factors are repetitive microtrauma, bleeding disorders, children born small for gestational age and/or with breech presentation [2] and environmental factors such as second hand smoke exposure [3]. While the etiology of LCP remains undefined, the pathophysiology is thought to result from a mismatch between growth of the femoral epiphyses and the slower development (or sometimes disruption) of vascular support to the area.

What Physical Exam findings are expected?

The diagnosis of LCP requires a high degree of clinical suspicion. Physical exam findings include decreased internal rotation and abduction of the hip, leg length discrepancy, and pain on rotation referred to the anteromedial thigh and/or knee [4]. Gait evaluation may find short-stance and/or Trendelenburg gait [4]

What is your disposition and management? Do I need an urgent Orthopedic consult?

Once the diagnosis of LCP has been made, the goal is to limit microvascular trauma and patients should be non-weight bearing while referral to pediatric orthopedic surgeon is made [5]. Emergent Orthopedic consultation is not typically required, but this may be system dependent. Treatment options typically consist of using braces and splints to contain the femoral head within the acetabulum or surgery [6]. Most patients experience improvement in pain initially, however long-term outcomes depend on age of onset (older than 6 y/o is less favorable) and the degree to which the femoral head was necrosed (greater than 50% is less favorable) [7,8].