Benign and Malignant Entities Affecting the Hip

Hip pain can often be a challenge-presenting complaint with a complicated differential diagnosis due to the numerous etiologies of both primary and referred hip pain. When evaluating hip pain, tumor or tumor-like conditions are often left off of the differential. The rarity and/or lack of familiarity with these conditions, the subtle appearance, or other distracting causalities of hip pain often contribute to this gap in diagnosis.

In this special edition of Journal of Hip Surgery, we present several articles that review the incidence, characteristics, and treatment of various benign and malignant tumors and tumor-like conditions that can affect the hip joint. We hope this collection of articles will better inform the medical community of the source of their patients' hip pain and lead them to more carefully evaluate their patients' hip pain.

The first article by Hoskins et al is a literature review and case series of several pediatric patients with a diagnosis of chondroblastoma of the femoral head. The patients had a delay of several months in appropriate diagnosis and treatment of this locally aggressive bone tumor. After diagnosis and treatment, all patients were able to return to their preoperative function with no local recurrence.

The next two articles by Patel and colleagues review various benign tumors and benign tumor-like conditions affecting the hip joint. These articles outline the incidence, symptomatology, diagnostic imaging features, and treatment options for unicameral bone cyst, aneurysmal bone cyst, osteochondroma, giant cell tumor, chondroblastoma, osteoid osteoma, osteoblastoma, fibrous dysplasia, Paget's disease, pigmented villonodular synovitis, transient osteoporosis, and synovial chondromatosis.

The fourth article by Gianakos and associates summarizes the diagnosis and treatment of several primary malignant tumors affecting the hip joint; osteosarcoma, chondrosarcoma, Ewing's sarcoma, undifferentiated pleomorphic sarcoma, fibrosarcoma of bone, and iatrogenic sarcomas. In treating these tumors often times the surgical treatment of choice is endoprosthetic reconstruction for a proximal femur replacement. The authors outline a brief endoprosthetic reconstruction technique of the proximal femur after tumor resection.

The fifth article by Miller and colleagues reviews various benign tumors and tumor-like conditions affecting the hip specifically in pediatric patients. Many times these tumors and lesions are found incidentally after patients present with pain after minor injury. Dr. Miller and his coauthors review the incidence, diagnosis, and treatment of these conditions as it pertains to the pediatric population.

In the final article by Gianakos et al, metastatic disease, multiple myeloma, and lymphoma—the three most common causes for bony lesions in patients over 40 years of age—are examined. These entities commonly present with lesions in the hip region. The authors highlight the diagnosis and treatment of these entities as it pertains to orthopaedic surgeons treating the hip. The article also outlines a surgical technique for a cemented long-stem hemiarthroplasty for treating these conditions when they affect the proximal femur.

It is our hope that these articles will help clinicians to become familiar with these benign and malignant tumors and tumor-like conditions affecting the hip joint, leading to more appropriate diagnosis and treatment for patients in a timely manner.