The articular surfaces of the hip include the femoral head and acetabulum. The femoral head is deeply recessed in the acetabulum, making surgical access difficult.

The articular cartilage of the hip joint is thickest ventrolaterally and becomes thinner in a concentric gradient toward the fovea of the femoral head and the acetabular fossa.¹⁹

The hip joint is surrounded anteriorly by the capsular, iliofemoral, and pubofemoral ligaments and posteriorly by the ischiofemoral ligament.

The labrum forms a C-shaped circumferential border around the acetabulum, attached to the transverse acetabular ligament posteriorly and anteriorly. It extends contact over the femoral head, maintains intra-articular negative pressure, and serves to augment and protect the articular cartilage.

Possible causes of chondral injury to the hip include trauma, femoroacetabular impingement, synovial disorders, instability, osteonecrosis, osteochondritis dissecans, osteoarthritis, slipped capital femoral epiphysis, and rheumatoid arthritis.¹⁶

Acute traumatic cartilage injury to the femoral head or acetabulum in the young athlete is often caused by a lateral impact injury, with impact loading over the greater trochanter.¹⁸

Chondral injury is associated with labral pathology. McCarthy et al²⁰ showed that 73% of patients with fraying or torn labrum had chondral damage.

Femoroacetabular impingement is one of the most common causes of hip chondral injury. Cam impingement leads to anterosuperior acetabular cartilage delamination without associated labral injury. Pincer impingement causes a contrecoup cartilage injury on the posteroinferior acetabulum with labral damage and ossification. Both pathologies commonly exist concurrently.⁴

Focal cartilage lesions increase the risk of progression to symptomatic osteoarthritis, especially for untreated defects larger than 2 cm without stable shoulders.²

Untreated cartilage injuries may precipitate the need for THA (FIG 1A).

The history and physical exam are used to determine whether the source of pain is intra-articular or extra-articular.

Patients display the C-sign to describe deep interior hip pain. Intra-articular injury typically does not present with pain on palpation.

There is no specific test for chondral injuries of the hip, although the flexion internal rotation (FIR), log roll test, and scour test are suggestive of intra-articular pathology.

Plain radiographs are the hallmark of assessing hip pathology, but their use is limited in detecting chondral defects.

Magnetic resonance imaging (MRI) is the gold standard in detecting cartilage injuries of the hip (FIG 2).

Noncontrast, cartilage-specific MRI sequencing has been proven effective, with strong agreement to arthroscopic findings. Mintz et al²¹ demonstrated 92% and 86% agreement of MRI and arthroscopic findings for femoral articular cartilage defects in 92 patients with two readers. Acetabular cartilage defects showed 88% and 85% agreement between MRI and arthroscopic assessment.

Magnetic resonance arthrography (MRA) may provide a more accurate assessment of chondral injury, with a contrast injection to outline the defect, although results have been less reliable than MRI. In addition, the contrast injection makes this a more invasive modality than MRI.

Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) enables assessment of glycosaminoglycan content and can thus detect deteriorating changes in cartilage. Cunningham et al⁸ showed that lower scores on the dGEMRIC index effectively predicted failure of periacetabular osteotomy.

Multidetector computed tomography arthrography (MDCTA) is another modality used to detect cartilage defects, but recent studies have shown conflicting levels of diagnostic accuracy.⁶,²³,²⁴

Ultrasound is a new option to diagnose hip injuries and can be used for diagnostic injections.

Non-hip

Hip

The first line of nonoperative treatment for cartilage injuries includes rest, physical therapy, nonsteroidal anti-inflammatory drugs, and intra-articular injections. Surgical treatment is indicated if hip pain persists.

There exist five surgical treatment options for cartilage injuries of the hip. These include débridement, direct suture repair, microfracture, osteochondral autograft transplantation (OATS), and autologous chondrocyte implantation or matrixinduced autologous chondrocyte implantation (ACI/MACI).
OATS and ACI are more commonly done as open procedures, whereas débridement, repair, and microfracture are conducted arthroscopically.

The surgical treatment of choice depends on patient age, acuity of injury, location and depth of defect, and surgeon’s experience with arthroscopic or open techniques (FIG 3).

Contraindications for any of the cartilage procedures include unwillingness or inability to complete the rehabilitation protocol as well as kissing lesions, advanced arthritis, and infection.