Modified Kerboul Angle Predicts Outcome of Core Decompression With or Without Additional Cell Therapy

Background: Core decompression is the most common procedure for early-stage osteonecrosis of the femoral head (ONFH). This study investigated outcomes of core decompression with/without bone marrow aspirate concentrate (BMAC), based on the Kerboul combined necrotic angles using magnetic resonance imaging. Methods: We reviewed 66 patients (83 hips) with early ONFH, Association Research Circulation Osseous stages I-IIIa, who underwent core decompression alone (26 patients, 33 hips) or in combination with BMAC (40 patients, 50 hips). Survival rate and progressive collapse were analyzed using the Kaplan-Meier method, and conversion to total hip arthroplasty (THA) was evaluated. Subgroup analyses based on the modified Kerboul angle were performed: grade I (<200 degrees), grade II (200 degrees-249 degrees), grade III (250 degrees-299 degrees), and grade IV (>= 300 degrees). Results: Mean follow-up was 36 +/- 23 months. Femoral head collapse with BMAC (16 hips, 32%) was significantly lower than without BMAC (19 hips, 58%, P=.019). Conversion THA was significantly lower with BMAC (28%) thanwithout (58%, P=.007). Survival rates among groups showed significant differences (P=.017). In grade I, 0/12 hips with BMAC collapsed while 3/9 (33%) without BMAC collapsed (P=.063); in grade II, 2/16 hips (12%) with BMAC collapsed while 7/13 (54%) without BMAC collapsed (P=.023). There was no significant difference in collapse with (64%) or without (82%) BMAC in grade III-IV hips (P=.256). Conclusion: Core decompression with/without BMAC had a high failure rate, by increasing disease progression and the necessity for THA, for combined necrotic angles >250 degrees. In our study, addition of BMAC had more reliable outcomes than isolated core decompression for precollapse ONFH if the combined necrotic angles were < 250 degrees. (C) 2021 Elsevier Inc. All rights reserved.