0
Editorial   |    
Comparing Two Articles on Osteonecrosis in Sickle Cell Disease
James V. LuckJr., MD1
1 Orthopaedic Hospital Los Angeles, California
View Disclosures and Other Information
The Journal of Bone and Joint Surgery, Incorporated
J Bone Joint Surg Am, 2006 Dec 01;88(12):2563-2564. doi: 10.2106/JBJS.F.01198
5 Recommendations (Recommend) | 3 Comments | Saved by 3 Users Save Case
This issue contains two articles on osteonecrosis of the femoral head in patients with sickle cell disease: "The Natural History of Asymptomatic Osteonecrosis of the Femoral Head in Adults with Sickle Cell Disease," by Hernigou et al., and "Physical Therapy Alone Compared with Core Decompression and Physical Therapy for Femoral Head Osteonecrosis in Sickle Cell Disease: Results of a Multicenter Study at a Mean of Three Years After Treatment," by Neumayr et al. Both are meaningful studies that add to our body of knowledge in the orthopaedic management of patients with sickle cell disease but appear to report strikingly different outcomes in similar patient populations. In the report by Hernigou et al., ninety-one (75%) of 121 patients required reconstructive surgery during the term of the study, with total hip replacement being performed in forty-two patients, valgus femoral osteotomy in twenty-three, and injection of cement into the femoral head in twenty-six. In comparison, in the study by Neumayr et al., only three (7.9%) of thirty-eight patients required reconstructive surgery in the form of total hip replacement. There are some similarities between the two studies, but several important differences may account for some of the variance in outcome. The two studies are compared in Table I. The average age (twenty-six years) was the same in both studies. However, the patients in the study by Neumayr et al. were as young as ten years old, whereas the youngest patient in the study by Hernigou et al. was eighteen years old. The prevalence of hemoglobin SS was 76% in the study by Neumayr et al., compared with 40% in the study by Hernigou et al. In the latter study, 48% of the patients had hemoglobin SC disease. Seventeen (45%) of the thirty-eight patients in the study by Neumayr et al. had Steinberg stage-III involvement at the beginning of the study, whereas none of the patients in the study by Hernigou et al. had more than stage-II involvement. Each of these factors might be expected to result in a worse outcome for the group in the study by Neumayr et al.
 
Anchor for JumpAnchor for JumpTABLE I  A Comparison of the Studies by Hernigou et al. and Neumayr et al.
Hernigou et al. Neumayr et al.
No. of participants/no. of patients who met selection criteria 121/121 38/176
Duration of follow-up*(yr) 14 (range, 10 to 20) 3
Age (yr) 26 (range, 18 to 31) 26 (minimum age, 10)
Steinberg stage (no. of patients)
    Stage 0 56 0
    Stage I 42 10
    Stage II 23 11
    Stage III 0 17
Hemoglobin SS 40% 76%
Percentage of patients at each Steinberg stage undergoing major surgery within three years†
    Stage 0 0% NA
    Stage I 20% 10%
    Stage II 60% 18%
    Stage III NA 18%
The values are given as the mean, with the range (or minimum value) in parentheses when available. †NA = not applicable.
The most critical difference between these two studies is the mean duration of follow-up: three years in the study by Neumayr et al. and fourteen years (range, ten to twenty years) in the study by Hernigou et al. If we look at comparable timelines, the percentage of patients with stage-I disease who required surgery after three years was not strikingly different: 20% in the study by Hernigou et al. and 10% in the study by Neumayr et al. However, for patients with stage-II disease, this value was 60% in the study by Hernigou et al. and only 18% in the study by Neumayr et al. None of the patients in the report by Hernigou et al. had stage-III disease at the start of the study. In the report by Neumayr et al., patients with stage-III disease had the same failure rate as did those with stage-I disease (18%). As stated above, these differences cannot be accounted for on the basis of disease severity.
The patient populations were very different in terms of selection. The study by Hernigou et al. included 121 consecutive patients, and none of the patients were lost to follow-up. In the study by Neumayr et al., 420 patients were screened, 176 met the selection criteria, and forty-six were selected. Eight of these patients declined to participate or were withdrawn from the study by the parents or the investigator. It is possible that one factor in this selection was patient cooperation and pain tolerance, which could affect disease management and possibly influence progression of the hip disease. Because of severely painful, episodic crises beginning in early childhood, many patients with sickle cell disease require regular use of narcotic analgesics, sometimes to extraordinary levels. Pain tolerance and the use of narcotic analgesics (both prescribed and self-procured) were not accounted for in the selection process and could have influenced the outcome. Narcotic use per month is listed for the patients in the study by Neumayr et al., but there are no data on the 138 patients who met the inclusion criteria but were screened out. A group of more cooperative patients with good pain tolerance would be expected to respond better to the physical therapy regimen and other conservative treatments than a group of less cooperative patients addicted to narcotic analgesics. Furthermore, surgical decision-making is based more on pain than on radiographic stage. Finally, eight patients in the study by Hernigou et al. had another risk factor (a history of use of steroid therapy or alcohol abuse) associated with sickle cell disease. Patients with these risk factors were eliminated in the study by Neumayr et al.
As pointed out in both articles, the prevalence of osteonecrosis in patients with sickle cell disease is very high, approaching 50%. As demonstrated by Hernigou et al. and others, progression to collapse is almost universal and the results of total hip replacement are much more problematic than in patients with other types of arthritis. The perioperative complication rate has been reported to be as high as 50%1, and the prevalence of late postoperative infection has been reported to approach 20%1-4. Given this scenario, therapies and non-arthroplasty procedures that will forestall, and possibly prevent, the need for total hip replacement are very attractive. The study by Neumayr et al. has demonstrated the efficacy of a physical therapy regimen that seems to decrease symptoms in a selected group of patients with sickle cell disease. How much it will forestall the need for total hip replacement will require much longer follow-up, and its effect on the full spectrum of patients with sickle cell disease will await a more inclusive study. The authors of both studies are to be congratulated for advancing our understanding of the orthopaedic management of this challenging condition.
Acurio MT, Friedman RJ. Hip arthroplasty in patients with sickle-cell haemoglobinopathy. J Bone Joint Surg Br.1992;74: 367-71.74367  1992  [PubMed]
 
Epps CH Jr, Bryant DD 3rd, Coles MJ, Castro O. Osteomyelitis in patients who have sickle-cell disease. Diagnosis and management. J Bone Joint Surg Am.1991;73: 1281-94.731281  1991  [PubMed]
 
Bishop AR, Roberson JR, Eckman JR, Fleming LL. Total hip arthroplasty in patients who have sickle-cell hemoglobinopathy. J Bone Joint Surg Am.1988; 70: 853-5.70853  1988  [PubMed]
 
Hanker GJ, Amstutz HC. Osteonecrosis of the hip in the sickle-cell diseases. J Bone Joint Surg Am.1988;70: 499-506.70499  1988  [PubMed]
 

Submit a comment

Anchor for JumpAnchor for JumpTABLE I  A Comparison of the Studies by Hernigou et al. and Neumayr et al.
Hernigou et al. Neumayr et al.
No. of participants/no. of patients who met selection criteria 121/121 38/176
Duration of follow-up*(yr) 14 (range, 10 to 20) 3
Age (yr) 26 (range, 18 to 31) 26 (minimum age, 10)
Steinberg stage (no. of patients)
    Stage 0 56 0
    Stage I 42 10
    Stage II 23 11
    Stage III 0 17
Hemoglobin SS 40% 76%
Percentage of patients at each Steinberg stage undergoing major surgery within three years†
    Stage 0 0% NA
    Stage I 20% 10%
    Stage II 60% 18%
    Stage III NA 18%
The values are given as the mean, with the range (or minimum value) in parentheses when available. †NA = not applicable.

References

Acurio MT, Friedman RJ. Hip arthroplasty in patients with sickle-cell haemoglobinopathy. J Bone Joint Surg Br.1992;74: 367-71.74367  1992  [PubMed]
 
Epps CH Jr, Bryant DD 3rd, Coles MJ, Castro O. Osteomyelitis in patients who have sickle-cell disease. Diagnosis and management. J Bone Joint Surg Am.1991;73: 1281-94.731281  1991  [PubMed]
 
Bishop AR, Roberson JR, Eckman JR, Fleming LL. Total hip arthroplasty in patients who have sickle-cell hemoglobinopathy. J Bone Joint Surg Am.1988; 70: 853-5.70853  1988  [PubMed]
 
Hanker GJ, Amstutz HC. Osteonecrosis of the hip in the sickle-cell diseases. J Bone Joint Surg Am.1988;70: 499-506.70499  1988  [PubMed]
 
Accreditation Statement
These activities have been planned and implemented in accordance with the Essential Areas and policies of the Accreditation Council for Continuing Medical Education (ACCME) through the joint sponsorship of the American Academy of Orthopaedic Surgeons and The Journal of Bone and Joint Surgery, Inc. The American Academy of Orthopaedic Surgeons is accredited by the ACCME to provide continuing medical education for physicians.
CME Activities Associated with This Article
Submit a Comment
Please read the other comments before you post yours. Contributors must reveal any conflict of interest.
Comments are moderated and will appear on the site at the discretion of JBJS editorial staff.

* = Required Field
(if multiple authors, separate names by comma)
Example: John Doe





Related Content
The Journal of Bone & Joint Surgery
JBJS Case Connector
Topic Collections
Hip
Related Audio and Videos
PubMed Articles
Clinical Trials
Readers of This Also Read...
JBJS Jobs
04/16/2014
Ohio - OhioHealth Research and Innovation Institute (OHRI)
10/04/2013
California - Mercy Medical Group
01/22/2014
Pennsylvania - Penn State Milton S. Hershey Medical Center