Proximal ITB Enthesopathy

Runners during the marathon REUTERS/Annegret Hilse.

Overuse hip injuries are common in runners due to repetitive microtrauma⁽¹⁾. Common conditions include proximal hamstring and hip flexor tendinopathies, greater trochanteric pain syndrome (GTPS), gluteus tears, and iliac crest stress injuries in adolescent athletes^(1,2). Clinicians define enthesopathy as the metabolic, inflammatory, traumatic, or degenerative pathological changes that occur at the enthesis⁽³⁾. Proximal iliotibial band (ITB) enthesopathy is often misdiagnosed, leading to ineffective treatment. Clinicians should consider this as a potential cause of lateral hip pain.

“Diagnosing proximal ITB enthesopathy can be challenging…”

Anatomy^(2,4-6)

 The fascia lata, or deep fascia, is a fibrous structure that envelops the hip and thigh musculature and attaches at multiple sites. The iliac tubercle is a prominent bony landmark on the outer lip of the iliac crest, located five centimeters posterior to the anterior superior iliac spine (ASIS), where the tensor fascia lata (TFL) originates at its anterior portion. Some fibers of the ITB attach to a distinct region of fascial thickening (see figure 1). At the proximal lateral aspect of the hip, the ITB blends with the TFL and gluteal aponeurotic fascia. Distally, the ITB inserts onto Gerdy’s tubercle at the lateral aspect of the tibia.

The enthesis is an area where tendon, ligament, fascia, or joint capsule inserts into bone. Entheses transmit tensile loads from soft tissue to bone and play a vital role by ensuring the efficient transfer of muscle-generated forces to the skeletal attachment, while also dispersing stress away from the enthesis, guiding it from the tendon into the bone. Entheses are classified according to the type of tissue present at the skeletal attachment site, i.e., dense fibrous connective tissue or fibrocartilage. Dense fibrous entheses are commonly attached to metaphyses and diaphyses of long bones, whereas fibrocartilaginous entheses are frequently attached to epiphyses and apophyses. The entheses of the ITB are fibrocartilaginous and are more prone to overuse.