Prevalence of Symptomatic Avascular Necrosis and the Operative Treatment in Adult Patients with Sickle Cell Disease

Introduction: Sickle cell disease (SCD) is complicated by widespread tissue and organ damage, including avascular necrosis (AVN) of the bones. Common sites of AVN include the shoulders and hips, which often causes severe pain and limited joint function, leading to surgical treatment. Although common, the prevalence of symptomatic AVN and optimal management for this disease has not been well defined. Furthermore, the overall effect of operative treatment on pain episodes requiring hospitalization is not known. The aim of this study is to retrospectively examine the prevalence of symptomatic AVN in adult SCD patients and assess the effects of surgical therapy.

Methods: The Adult Hemoglobinopathy Resource Center at Washington University provides care for adult SCD patients throughout the St. Louis, Missouri metropolitan area. All patients have confirmed SCD (Hgb SS, Hgb SC, Hgb Sβ⁺, Hgb Sβ⁰, Hgb SC Harlem, Hgb SOther) and have been seen at least once since 2011 to be included in the study. Patients with new onset or worsening hip or shoulder pain underwent imaging studies and the presence or absence of radiographic evidence of AVN was used to determine the prevalence. The medical record was reviewed to identify patients with orthopedic procedures for AVN. The operative history of individuals with AVN was assessed and data from the post-operative hospital course was collected. The medical record was also reviewed to assess for subsequent hospitalizations and to determine whether the complications were directly related to the surgery or not. Medical record data was collected through June 2014. The surgical procedures were determined by the treating orthopedists and were not prospectively evaluated.

Results: From October 2011 to June 2014, 324 patients have been evaluated. Of these patients, the mean age is 36 years (range 18-81); 180 are female (55.6%), and 144 are male (44.4%). The hemoglobinopathies include SS-205, SC-90, Sβ⁺-21, Sβ⁰-5, SC Harlem-2, and one unconfirmed genotype of SCD because of longstanding chronic transfusions. Out of the 324 patients, 94 (29%) had clinical and radiographic findings consistent with AVN of the hip(s) and 64 (19.8%) had findings consistent with AVN of the shoulder(s). No statistical difference was detected between genders (p >0.5) or among the genotypes, including between hemoglobin SS and SC (p>0.3). Forty-eight patients underwent 74 operations for AVN including 50 hip and 24 shoulder procedures. For the hip surgeries, these included 44 total hip arthroplasties, 2 hemiarthroplasties, 2 core decompressions and 2 other operative procedures. For the shoulder procedures, there were 11 total shoulder arthroplasties, 4 hemiarthroplasties, 8 core decompressions and 1 other operative treatment. All patients received pre-operative red cell transfusion support. The mean post-operative time in the hospital was 3.6 days (range <1-8) for hip surgery and 2.4 days (range <1-8) for shoulder surgery. Notably, there were thirteen re-hospitalizations within 30 days of surgery but these were all felt to be for pain syndromes not directly related to the surgical site. Fourteen patients were readmitted over the course of their care for joint-related complications resulting in 6 surgical revisions. Three had hemiarthroplasties converted to total arthroplasties, including both patients who originally received hip hemiarthroplasties. Both patients who underwent hip core decompressions later received total hip arthroplasties in those joints, and one patient of a shoulder core decompression also required total joint replacement. With three years of follow up, one patient underwent surgical removal of the prosthesis and insertion of an antibiotic spacer to treat a possible infection. Overall, patients who underwent surgical treatment for AVN had 2.4 hospitalizations per year for either joint related complications or other SCD related issues.

Conclusion: SymptomaticAVN of hips and shoulders is a frequently occurring complication for patients with SCD. This data supports the role for joint replacement surgery as an effective treatment to improve joint function with a low risk of complications. However, hospitalizations for other complications of SCD, particularly sickle cell related pain, continue to occur and strategies for preventing AVN remain to be defined.