Introduction: Sickle cell disease (SCD) is one of the most prevalent hemoglobinopathies worldwide. This autosomal recessive disorder leads to hemolysis, life-threatening acute complications, and chronic damage to various organs. A significant chronic complication that adversely affects patients' quality of life is avascular necrosis (AVN). Although the exact prevalence of AVN in SCD is not well established, studies utilizing magnetic resonance imaging (MRI) report a prevalence of up to 41%. The femoral head is the most commonly affected site. AVN can occur at any age, while its frequency increases with advancing age. This study aimed to investigate the frequency of femoral head AVN in patients with SCD, its association with other acute and chronic SCD complications, and treatment approaches in patients seen at pediatric and adult hematology departments in the Çukurova region of Türkiye, where SCD is prevalent.Methods: A total of 329 SCD patients followed up between January 2017 and January 2025 in two university hospitals were included in the study. Demographic and clinical characteristics (acute and chronic complications related to SCD, transfusion frequency in the last year, and hydroxyurea use) were noted. Age of diagnosis of AVN, bone affected by AVN and treatment applied for AVN were obtained from the web-based National Hemoglobinopathy Registry System. Femoral head AVN was diagnosed using plain radiography and MRI and staged according to the Ficat and Arlet classification system. The study was conducted in accordance with the ethical standards described in the Declaration of Helsinki.

Results: Of the 329 patients, 172 (52.3%) were female and 157 (47.7%) were male, with a median age of 38 years (IQR: 28 – 50 years, 18 pediatric and 311 adult patients). Femoral head AVN was detected in 126 (38%) patients (68 female, 58 male). The median age of femoral head AVN diagnosis was 26 years (IQR: 18 – 34 years). 32/126 (25.4%) patients were under 18 years of age at the time of femoral head AVN diagnosis. 26/126 (20.6%) patients with femoral head AVN had Ficat stage III and 70/126 (55.6%) had Ficat stage IV AVN, and 95/126 (75.4%) had bilateral involvement. There was no significant difference between patients with and without femoral head AVN in terms of chronic organ damage, hydroxyurea use, and compliance to hydroxyurea treatment (p > 0.05). The frequency of HbSS genotype, number of attacks of painful crises per year, number of simple transfusions per year, and number of past acute chest syndrome was higher in patients with femoral head AVN compared to patients without (p = 0.032, p < 0.001, p = 0.003, and p < 0.001, respectively). Compared with SCD without acute painful crises, SCD with 1-2 attacks of acute painful crises/year was not associated with the occurrence of femoral head AVN (p = 0.096). Patients with 3-4 attacks of acute painful crises per year were at 3.3 times greater risk of having femoral head AVN [Odds (95% CI) = 3.26 (1.27 - 8.38), p = 0.014] while patients with ≥ 5 attacks of acute painful crises per year were at 6.4 times greater risk of having femoral head AVN [Odds (95% CI) = 6.35 (1.99 – 20.18), p = 0.002]. The most common treatment for femoral head AVN was physiotherapy (64.3%, n = 81/126) while 33/126 (26.2%) patients underwent arthroplasty. Despite treatment, 84.8% of patients with femoral head AVN continued to experience pain and limitation of movement ability.

Conclusions: Femoral head AVN is a frequent and morbidity-increasing complication in patients with SCD. It is more common in patients with more severe clinical symptoms. Frequency of vaso-occlusive crisis/year is associated with the occurrence of femoral head AVN and despite treatment, clinical symptoms may persist in SCD patients with femoral head AVN. Notably, most patients are diagnosed at a late stage. These findings underscore the importance of early diagnosis and effective management strategies.

This content is only available as a PDF.
2025
Sign in via your Institution