What joint‑preserving treatment is recommended for a patient with early‑stage (Ficat and Association Research Circulation Osseous grade II) avascular necrosis of the femoral head using autologous bone‑marrow aspirate concentrate?

Core Decompression with Autologous Bone Marrow Aspirate Concentrate for Grade II AVN

For Ficat/ARCO Grade II avascular necrosis of the femoral head, core decompression is the primary surgical intervention, achieving approximately 88% success rates when performed at this stage, and while autologous bone marrow aspirate concentrate (BMAC) can be added as an adjunct, the evidence supporting its additional benefit over core decompression alone remains controversial. 1

Primary Surgical Recommendation

• Core decompression is the definitive joint-preserving procedure for Grade II (pre-collapse) AVN, with the goal of preventing articular collapse and postponing or avoiding total hip replacement. 1

• Success rates are stage-dependent: approximately 92% for Stage I and 88% for Stage II disease when patients adhere to postoperative protocols. 1

• The procedure should not be delayed, as success rates decline sharply once articular collapse occurs—dropping to only 14% in Stage IV disease. 1, 2

Role of Bone Marrow Aspirate Concentrate

• BMAC supplementation remains controversial despite being mentioned as a potential adjunct to core decompression. 1

• The highest-quality recent evidence shows no enhanced efficacy when BMAC is added to core decompression in terms of:

  • Delaying radiographic progression (Odds ratio 1.41,95% CI 0.55-3.62) 3
  • Preventing conversion to total hip arthroplasty (Odds ratio 0.92,95% CI 0.41-2.06) 3

• However, one prospective randomized controlled trial (2014) demonstrated that BMAC combined with core decompression showed superior outcomes for early-stage disease:

  • Significant pain relief at 24 months (P <0.05) 4
  • Only 8% progression to next stage versus 33.3% with core decompression alone (P <0.05) 4
  • 100% non-progression rate for Stage I/II hips in the BMAC group versus 66.7% in controls 4

Reconciling Contradictory Evidence

The divergence in outcomes likely reflects differences in patient selection and disease stage. For Grade II AVN specifically, BMAC may provide additional benefit in preventing progression, particularly when the necrotic lesion is well-targeted. 4, 5 The negative meta-analysis included predominantly post-collapse (Stage III-IV) cases where BMAC showed no benefit. 3

Prognostic Factors That Mandate Intervention

Before proceeding, assess these critical risk factors that predict collapse:

• Lesion size >30% of femoral head carries 46-83% risk of progression to collapse versus <5% for lesions <30%. 1

• Age >40 years and BMI >24 kg/m² independently increase collapse risk. 1

• Presence of joint effusion or bone marrow edema on MRI signals higher progression risk. 1

Surgical Technique Considerations

• CT-based three-dimensional modeling with computer navigation improves targeting of the necrotic lesion center, potentially enhancing outcomes by ensuring precise delivery of therapy. 6

• The procedure minimizes attempts to reach the lesion and confirms three-dimensional positioning within the necrotic zone. 6

Alternative Adjuncts Beyond BMAC

• Vascularized fibular grafts or electric stimulation may be employed as alternatives, though their efficacy also remains controversial. 1

• Non-invasive modalities (statins, bisphosphonates, anticoagulants, extracorporeal shock-wave therapy, hyperbaric oxygen) have limited supporting data but can be considered as adjuncts. 1

Critical Pitfalls to Avoid

• Do not perform core decompression once articular collapse is evident—success rates plummet and arthroplasty becomes indicated. 1

• Evaluate the contralateral hip, as 70-80% of nontraumatic AVN cases are bilateral. 1, 7

• Screen for multifocal involvement: knee (44%), ankle (17%), shoulder (15%) can be affected. 1

• Ensure postoperative protocol adherence is emphasized, as the 88% success rate depends on patient compliance. 1

When to Proceed Directly to Arthroplasty

• Resurfacing hemiarthroplasty is indicated once late-stage osteonecrosis with confirmed articular collapse occurs. 1

• Total hip arthroplasty is reserved for severe secondary osteoarthritis. 1

• AVN accounts for approximately 10% of all total hip replacements in the United States. 1