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Widening of the narrow rheumatoid knee joint space associated with combination of methotrexate and abatacept therapy
Hitoshi Imamura1, Katsunori Ikari1
1MD, PhD, Department of Orthopedic Surgery, Institute of Rheumatology, Tokyo Women’s Medical University, Shinjuku, Tokyo, Japan

Article ID: 100887Z01HI2018
doi: 10.5348/100887Z01HI2018CL

Corresponding Author:
Hitoshi Imamura,
MD, PhD, Department of Orthopedic Surgery,
Institute of Rheumatology, Tokyo Women’s Medical University,
Tokyo, Japan, 10-22 Kawada, Shinjuku,
Tokyo 162-0054 Japan

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How to cite this article
Imamura H, Ikari K. Widening of the narrow rheumatoid knee joint space associated with combination of methotrexate and abatacept therapy. Int J Case Rep Images 2018;9:100887Z01HI2018.


CASE REPORT

A 65-year-old female was diagnosed with rheumatoid arthritis about 10 years. She had experienced continous severe knee pain from the last six months in her right knee. She had undergone treatment with methotrexate (MTX) 6–8 mg/week as the sole regimen over the last eight years. At this time, the patient was walking with the aid of crutches, and her Knee Society Knee Score and Functional Score [1] were 47 points and 5 points, respectively. Severe joint space narrowing was evident on upright anteroposterior radiography (Figure 1A), which is an indication for total knee arthroplasty. Due to persistent disease activity (DAS28 = 4.1), the patient was started on MTX 8 mg/week plus intravenous abatacept 500 mg/month. After 18 months of this treatment, there was improvement of symptoms, mostly in the right knee. The patient’s Knee Society Knee Score and Functional Score had increased to 80 points and 60 points, respectively. She was able to walk independently without crutches, and upright anteroposterior radiography showed widening of the narrow knee joint space (Figure 1B).


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Figure 1: Upright anteroposterior knee radiography (A) Before abatacept introduction, (B) After 18 months of abatacept introduction.



DISCUSSION

To date, abatacept has been known as an agent that reduces the progression of radiographic structural damage in rheumatoid arthritis patients with an inadequate response to MTX [2][3][4] . However, this case showed widening of the narrow knee joint space after the introduction of abatacept treatment. We believe that our case is the first to demonstrate this knee joint space widening, which is expected to be extended with longer-term observations of this rheumatoid knee. As both the Knee Society Knee Score and Functional Score were also improved, it is likely that the impaired cartilage tissue within the right knee joint was being substituted by cartilage-like tissue through some as yet unclarified mechanisms. This change likely occurred because combined methotrexate and abatacept therapy has a strong effect on the chemical environment and cartilage regeneration within the rheumatoid knee joint.


CONCLUSION

This case showed widening of the narrow rheumatoid knee joint space associated with combination therapy with methotrexate plus abatacept. In addition, both the Knee Society Knee Score and functional score were also improved after the introduction of this combination therapy. Additional work is required for understanding the rheumatology underlying this case.

Keywords: Abatacept, Knee joint space, Methotrexate, Rheumatoid arthritis


REFERENCES
  1. Insall JN, Dorr LD, Scott RD, Scott WN. Rationale of the Knee Society clinical rating system. Clin Orthop Relat Res 1989 Nov;(248):13–4.   [CrossRef]   [Pubmed]    Back to citation no. 1
  2. Kremer JM, Genant HK, Moreland LW, et al. Effects of abatacept in patients with methotrexate-resistant active rheumatoid arthritis: A randomized trial. Ann Intern Med 2006 Jun 20;144(12):865–76.   [CrossRef]   [Pubmed]    Back to citation no. 2
  3. Genant HK, Peterfy CG, Westhovens R, et al. Abatacept inhibits progression of structural damage in rheumatoid arthritis: Results from the long-term extension of the AIM trial. Ann Rheum Dis 2008 Aug;67(8):1084–9.   [CrossRef]   [Pubmed]    Back to citation no. 3
  4. Kremer JM, Peterfy C, Russell AS, et al. Longterm safety, efficacy, and inhibition of structural damage progression over 5 years of treatment with abatacept in patients with rheumatoid arthritis in the abatacept in inadequate responders to methotrexate trial. J Rheumatol 2014 Jun;41(6):1077–87.   [CrossRef]   [Pubmed]    Back to citation no. 4

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Author Contributions
Hitoshi Imamura – Substantial contributions to conception and design, Acquisition of data, Analysis and interpretation of data, Drafting the article, Revising it critically for important intellectual content, Final approval of the version to be published
Katsunori Ikari – Substantial contributions to conception and design, Drafting the article, Final approval of the version to be published
Guarantor of Submission
The corresponding author is the guarantor of submission.
Source of Support
None
Consent Statement
Written informed consent was obtained from the patient for publication of this case report.
Conflict of Interest
Author declares no conflict of interest.
Copyright
© 2018 Hitoshi Imamura et al. This article is distributed under the terms of Creative Commons Attribution License which permits unrestricted use, distribution and reproduction in any medium provided the original author(s) and original publisher are properly credited. Please see the copyright policy on the journal website for more information.