Computed tomography for the detection of thumb base osteoarthritis, comparison with digital radiography.

Transcription

1 Computed tomography for the detection of thumb base osteoarthritis, comparison with digital radiography. Poster No.: C-1981 Congress: ECR 2012 Type: Scientific Exhibit Authors: M. S. Saltzherr, J. W. van Neck, G. Muradin, R. Ouwendijk, J. J. Luime, J. H. Coert, S. E. R. Hovius, R. W. Selles; Rotterdam/NL Keywords: DOI: Comparative studies, Digital radiography, CT, Bones, Musculoskeletal joint, Arthritides /ecr2012/C-1981 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 12

2 Purpose Osteoarthritis of the thumb base Osteoarthritis (OA) of the thumb base or first carpometacarpal (CMC1) joint is a common condition, particularly in elderly women.[1] Typically, patients have activity-related pain localised at the base of the thumb and have a loss of hand function. Diagnosis and treatment The diagnosis of CMC1 OA and the selection of treatment are usually based on a combination of clinical symptoms and radiography. The radiographic Eaton and Glickel system classifies CMC1 OA into one of four radiographic stages, with each stage requiring different types of treatment.[2] The main difference between Eaton stage III and Eaton stage IV is the absence or presence of OA of the adjacent scapho-trapezialtrapezoidal (STT) joint. Eaton stage 3 can be treated with a hemi-trapezectomy, while surgery of Eaton stage 4 requires more invasive surgery that also adresses the STT joint. Detection of STT OA is therefore important, but it can be difficult to evaluate on a radiograph. CT (Computed Tomography) might improve detection, due to its higher spatial resolution. The purpose of this study was to compare CT with digital radiography in detecting osteoarthritis of the CMC1 and STT joint. Page 2 of 12

3 Methods and Materials Patient selection We retrospectively identified patients clinically suspected for CMC1 OA or STT OA between January 2008 and March 2011 at our Plastic, Reconstructive and Hand surgery outpatient clinic, who had both a digital radiograph and a CT-scan of the hand within a period of three months. Image evaluation The CT and radiographic images were scored independently and in random time order by two musculoskeletal radiologists, using a scoring system based on the Eaton and Glickel classification system[2] and the OARSI atlas[3]. Both the CMC1 and the STT joint were scored for joint space narrowing, osteophytes, subchondral sclerosis, bone cysts and erosions. An overview of the used scoring system is shown in Table 1 on page 4. For our analysis STT OA was defined as one or more "present" scores in the STT joint or 3 or more "doubtful" scores. Statistics Inter-reader agreement was calculated as a percentage agreement. Sensitivity and specificity of radiography for detecting STT OA were calculated, with CT used as the reference standard. Page 3 of 12

4 Images for this section: Table 1: Overview of the used scoring system. All CT and radiographic images were scored with this scoring system. Radiology, Erasmus MC, University Medical Center - Rotterdam/NL Page 4 of 12

5 Results Patient characteristics The images of 30 patients were scored and analyzed. Twenty-one of these patients were female, the median age was 57 years (inter quartile range 53-61), and 21 right and 9 left hands were assessed. Scoring results The inter-reader agreement summarized over all scored items was 77% for CT and 82% for radiography. In Table 2 on page 6 the scoring results of both readers for the radiographic and and CT images are shown. The number of subjects in which pathology was detected with CT and not with radiography for the first en second reader respectively were: CMC1 joint space narrowing: 8 and 2 CMC1 osteophytes: 7 and 5 CMC1 subchondral sclerosis: 12 and 20 CMC1 cysts: 11 and 11 CMC1 erosions: 2 and 0 STT joint space narrowing: 7 and 4 STT osteophytes: 4 and 2 STT subchondral sclerosis: 10 and -9 STT cysts: 9 and 6 STT erosions: 1 and 13 Two examples of STT joint space narrowing that are not detected with radiography but are detected with CT are shown in Fig. 1 on page 6 and Fig. 2 on page 7. Two by two tables for the detected STT OA by radiography and CT are shown in Table 3 on page 8. Sensitivity and specificity of radiography for the detection of STT OA with CT as the reference standard was 0.32 and 1.00 for reader 1, and 0.69 and 0.93 for reader 2. Page 5 of 12

6 Images for this section: Table 2: Scoring results of radiography and CT for both readers. Numbers represent the number of patients that were given that score. DR = digital radiography Radiology, Erasmus MC, University Medical Center - Rotterdam/NL Page 6 of 12

7 Fig. 1: Example of a patient in which STT OA was not detected with radiography. The scaphoid-trapezium joint space seem normals on the radiographs. However, on the CT images focal joint space narrowing between the scaphoid and the trapezium is visible. Radiology, Erasmus MC, University Medical Center - Rotterdam/NL Page 7 of 12

8 Fig. 2: Example of a patient with CMC1 OA in which STT OA was only detected with CT and not with radiography. The radiograph shows joint space narrowing, subchondral sclerosis and subluxation at the CMC1 joint, but the trapezium-trapezoid joint is hard to asses. The CT images also clearly shows these features at the CMC1 joint (top right), but additionally show joint space narrowing between the trapezium and the trapezoid (bottom pictures). Radiology, Erasmus MC, University Medical Center - Rotterdam/NL Page 8 of 12

9 Table 3: Two by two tables for the detected STT OA by both CT and radiography. Both readers have their own table. DR = Digital Radiography Radiology, Erasmus MC, University Medical Center - Rotterdam/NL Page 9 of 12

10 Conclusion Inter-reader reliability of CT is comparable to radiography. However, CT detected more OA pathology than CR. Since treatment selection of thumb base OA strongly depends on pathology presence of both the CMC1 and STT joint, CT may improve treatment selection and patient outcome. Page 10 of 12

11 References 1. Armstrong AL, Hunter JB, Davis TR. The prevalence of degenerative arthritis of the base of the thumb in post-menopausal women. J Hand Surg Br 1994;19(3): Eaton RG, Glickel SZ. Trapeziometacarpal osteoarthritis. Staging as a rationale for treatment. Hand Clin 1987;3(4): Altman RD, Gold GE. Atlas of individual radiographic features in osteoarthritis, revised. Osteoarthritis Cartilage 2007;15 Suppl A:A1-56. Page 11 of 12

12 Personal Information M. S. Saltzherr, MD. Department of Radiology Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands. Page 12 of 12