Rare Bi-focal Presentation of Avascular Necrosis of the Femoral Head: Successful Targeted Treatment as per the Diamond Concept and Review of the Literature

Avascular necrosis of the femoral head (AVNFH) is relatively infrequent, but if undiagnosed or untreated, it may result in significant functional disability, and due to severe ongoing pain, a total hip replacement (THR) may be necessitated. Most cases are associated with trauma, but a number of established risk factors exist. Diagnosis can be challenging but relies on clinical history, physical examination, and radiology. X-ray and MRI are used to stage avascular necrosis (AVN) lesions, which in turn influence management decisions. We present a male in his early 40s, diagnosed with a right-sided AVNFH (Ficat-Arlet stage I) five years previously at another centre. A number of risk factors were identified, such as chronic alcohol abuse, smoking, obesity, and Klinefelter’s syndrome. A 'watch and wait' approach was adopted, which included advice on reducing risk factors and commencement on aspirin and alendronic acid. However, his pain had recently increased, resulting in a significant reduction in mobility and an increased reliance on opiates. MRI demonstrated progression to Ficat-Arlet stage II, and the appearance of an additional smaller, second lesion located more medially in the same femoral head. Due to his symptom severity, he was offered a THR. In view of his young age, he came to our tertiary referral centre for a second opinion. He elected for a simultaneous dual surgical decompression of both AVN lesions and biological stimulation for bone-guided regeneration. This involved the delivery of growth factor (bone morphogenetic protein), progenitor cells, and a scaffold/matrix. At 36 months post-operatively, he continued to have the full, pain-free weight-bearing functional capacity, with radiographic imaging demonstrating no residual AVN or femoral head structural collapse. This was a unique case of bi-focal femoral head lesions, treated successfully with decompressions and biological enhancement using the 'diamond concept' for bone repair. In similar situations, when salvage of the femoral head is the preferred treatment option, such a strategy should be considered in the surgeon’s armamentarium.