EX-3.1

Exhibit 3.1

CERTIFICATE OF AMENDMENT
OF THE
RESTATED CERTIFICATE OF INCORPORATION
OF
REPLIDYNE, INC.

REPLIDYNE, INC. (the “Corporation”), a corporation organized and existing under and by virtue of the General Corporation Law of the State of Delaware (the “DGCL”), hereby certifies as follows:

FIRST: The name of the Corporation is Replidyne, Inc. A Certificate of Incorporation of the Corporation originally was filed by the Corporation with the Secretary of State of Delaware on December 6, 2000.

SECOND: This Certificate of Amendment amends the Restated Certificate of Incorporation of the Corporation and was duly adopted by the board of directors of the Corporation in accordance with the provisions of Sections 141 and 242 of the DGCL.

THIRD: The text of the Restated Certificate of Incorporation of the Corporation is hereby amended as follows:

1. Article I of the Restated Certificate of Incorporation of the Corporation is hereby amended and restated as follows:

“The name of this corporation is Cardiovascular Systems, Inc.”

2. Article IV of the Restated Certificate of Incorporation of the Corporation is hereby amended and restated as follows:

“A. Without regard to any other provision of this Restated Certificate of Incorporation, each one (1) share of Common Stock, either issued and outstanding or held by the corporation as treasury stock, immediately prior to the time this Certificate of Amendment becomes effective shall be and is hereby automatically reclassified and changed (without any further act) into one-tenth of a fully-paid and nonassessable share of Common Stock; provided, that no fractional shares shall be issued to any stockholder and no certificates or scrip for any such fractional shares shall be issued, each stockholder otherwise entitled to receive a fractional share shall receive the next lower whole number of shares of Common Stock, and the corporation shall pay in cash the dollar amount of such fractional shares (to the nearest whole cent), without interest, determined in each case by multiplying such fraction by the closing price of a share of Common Stock on the NASDAQ Global Market on the date immediately preceding the date on which this Certificate of Amendment becomes effective.

B. This corporation is authorized to issue two classes of stock to be designated, respectively, “Common Stock” and “Preferred Stock.” The total number of shares which the corporation is authorized to issue is one hundred and five million (105,000,000) shares. One hundred million (100,000,000) shares shall be Common Stock, each having a par value of one-tenth of one cent ($.001). Five million (5,000,000) shares shall be Preferred Stock, each having a par value of one-tenth of one cent ($.001).

C. The Preferred Stock may be issued from time to time in one or more series. The Board of Directors is hereby expressly authorized to provide for the issue of all or any of the shares of the Preferred Stock in one or more series, and to fix the number of shares and to determine or alter for each such series, such voting powers, full or limited, or no voting powers, and such designation, preferences, and relative, participating, optional, or other rights and such qualifications, limitations, or restrictions thereof, as shall be stated and expressed in the resolution or resolutions adopted by the Board of Directors providing for the issuance of such shares and as may be permitted by the DGCL. The Board of Directors is also expressly authorized to increase or decrease the number of shares of any series subsequent to the issuance of shares of that series, but not below the number of shares of such series then outstanding. In case the number of shares of any series shall be decreased in accordance with the foregoing sentence, the shares constituting such decrease shall resume the status that they had prior to the adoption of the resolution originally fixing the number of shares of such series. The number of authorized shares of Preferred Stock may be increased or decreased (but not below the number of shares thereof then outstanding) by the affirmative vote of the holders of a majority of the Common Stock, without a vote of the holders of the Preferred Stock, or of any series thereof, unless a vote of any such holders is required pursuant to the terms of any certificate of designation filed with respect to any series of Preferred Stock.

D. Each outstanding share of Common Stock shall entitle the holder thereof to one vote on each matter properly submitted to the stockholders of the Corporation for their vote; provided, however, that, except as otherwise required by law, holders of Common Stock shall not be entitled to vote on any amendment to this Certificate of Incorporation (including any certificate of designation filed with respect to any series of Preferred Stock) that relates solely to the terms of one or more outstanding series of Preferred Stock if the holders of such affected series are entitled, either separately or together as a class with the holders of one or more other such series, to vote thereon by law or pursuant to this Certificate of Incorporation (including any certificate of designation filed with respect to any series of Preferred Stock).”

FOURTH: Thereafter pursuant to a resolution of the board of directors of the Corporation, this Certificate of Amendment was submitted to the stockholders of the Corporation for their approval, and was duly adopted at a special meeting of the stockholders in accordance with the provisions of Section 242 of the DGCL.

IN WITNESS WHEREOF, Replidyne, Inc. has caused this Certificate of Amendment to be signed by its duly authorized officer this 25th day of February, 2009.


	Replidyne, Inc.
	By:	/s/ Kenneth J. Collins
		Kenneth J. Collins
		President and Chief Executive Officer

RESTATED CERTIFICATE OF INCORPORATION
OF
REPLIDYNE, INC.

REPLIDYNE, INC. (“Corporation”), a corporation organized and existing under and by virtue of the General Corporation Law of the State of Delaware (the “General Corporation Law”), hereby certifies as follows:

SECOND: This Restated Certificate of Incorporation restates and integrates and further amends the Certificate of Incorporation of the Corporation, was duly adopted in accordance with the provisions of Sections 242 and 245 of the Delaware General Corporation Law, and was approved by written consent of the stockholders of the Corporation given in accordance with the provisions of Section 228 of the Delaware General Corporation Law (prompt notice of such action having been given to those stockholders who did not consent in writing).

THIRD: The text of the Certificate of Incorporation of the Corporation is hereby restated and amended to read in its entirety as follows:

The name of this corporation is Replidyne, Inc.

II.

The address of the registered office of the Corporation in the State of Delaware is 1209 Orange Street, Wilmington, Delaware 19801, (County of New Castle). The name of the registered agent of the Corporation at such address is The Corporation Trust Company.

III.

The purpose of this corporation is to engage in any lawful act or activity for which a corporation may be organized under the Delaware General Corporation Law (“DGCL”).

IV.

A. This corporation is authorized to issue two classes of stock to be designated, respectively, “Common Stock” and “Preferred Stock.” The total number of shares which the corporation is authorized to issue is one hundred five million (105,000,000) shares. One hundred million (100,000,000) shares shall be Common Stock, each having a par value of one-tenth of

one cent ($.001). Five million (5,000,000) shares shall be Preferred Stock, each having a par value of one-tenth of one cent ($.001).

B. The Preferred Stock may be issued from time to time in one or more series. The Board of Directors is hereby expressly authorized to provide for the issue of all of any of the shares of the Preferred Stock in one or more series, and to fix the number of shares and to determine or alter for each such series, such voting powers, full or limited, or no voting powers, and such designation, preferences, and relative, participating, optional, or other rights and such qualifications, limitations, or restrictions thereof, as shall be stated and expressed in the resolution or resolutions adopted by the Board of Directors providing for the issuance of such shares and as may be permitted by the DGCL. The Board of Directors is also expressly authorized to increase or decrease the number of shares of any series subsequent to the issuance of shares of that series, but not below the number of shares of such series then outstanding. In case the number of shares of any series shall be decreased in accordance with the foregoing sentence, the shares constituting such decrease shall resume the status that they had prior to the adoption of the resolution originally fixing the number of shares of such series. The number of authorized shares of Preferred Stock may be increased or decreased (but not below the number of shares thereof then outstanding) by the affirmative vote of the holders of a majority of the Common Stock, without a vote of the holders of the Preferred Stock, or of any series thereof, unless a vote of any such holders is required pursuant to the terms of any certificate of designation filed with respect to any series of Preferred Stock.

C. Each outstanding share of Common Stock shall entitle the holder thereof to one vote on each matter properly submitted to the stockholders of the Corporation for their vote; provided, however, that, except as otherwise required by law, holders of Common Stock shall not be entitled to vote on any amendment to this Certificate of Incorporation (including any certificate of designation filed with respect to any series of Preferred Stock) that relates solely to the terms of one or more outstanding series of Preferred Stock if the holders of such affected series are entitled, either separately or together as a class with the holders of one or more other such series, to vote thereon by law or pursuant to this Certificate of Incorporation (including any certificate of designation filed with respect to any series of Preferred Stock).

For the management of the business and for the conduct of the affairs of the corporation, and in further definition, limitation and regulation of the powers of the corporation, of its directors and of its stockholders or any class thereof, as the case may be, it is further provided that:

1. Board of Directors. The management of the business and the conduct of the affairs of the corporation shall be vested in its Board of Directors. The number of directors which shall constitute the Board of Directors shall be fixed exclusively by resolutions adopted by a majority of the authorized number of directors constituting the Board of Directors.

2. Election of Directors

a. Subject to the rights of the holders of any series of Preferred Stock to elect additional directors under specified circumstances, following the closing of the initial public offering pursuant to an effective registration statement under the Securities Act of 1933, as amended (the “1933 Act”), covering the offer and sale of Common Stock to the public (the “Initial Public Offering”), the directors shall be divided into three classes designated as Class I, Class II and Class III, respectively. At the first annual meeting of stockholders following the closing of the Initial Public Offering, the term of office of the Class I directors shall expire and Class I directors shall be elected for a full term of three years. At the second annual meeting of stockholders following the closing of the Initial Public Offering, the term of office of the Class II directors shall expire and Class II directors shall be elected for a full term of three years. At the third annual meeting of stockholders following the closing of the Initial Public Offering, the term of office of the Class III directors shall expire and Class III directors shall be elected for a full term of three years. At each succeeding annual meeting of stockholders, directors shall be elected for a full term of three years to succeed the directors of the class whose terms expire at such annual meeting.

b. Notwithstanding the foregoing provisions of this section, each director shall serve until his successor is duly elected and qualified or until his death, resignation or removal. No decrease in the number of directors constituting the Board of Directors shall shorten the term of any incumbent director.

3. Vacancies. Subject to the rights of the holders of any series of Preferred Stock, any vacancies on the Board of Directors resulting from death, resignation, disqualification, removal or other causes and any newly created directorships resulting from any increase in the number of directors, shall, unless the Board of Directors determines by resolution that any such vacancies or newly created directorships shall be filled by the stockholders, except as otherwise provided by law, be filled only by the affirmative vote of a majority of the directors then in office, even though less than a quorum of the Board of Directors, and not by the stockholders. Any director elected in accordance with the preceding sentence shall hold office for the remainder of the full term of the director for which the vacancy was created or occurred and until such director’s successor shall have been elected and qualified.

1. Bylaw Amendments. The Board of Directors is expressly empowered to adopt, amend or repeal the Bylaws of the corporation. The stockholders shall also have power to adopt, amend or repeal the Bylaws of the corporation; provided, however, that, in addition to any vote of the holders of any class or series of stock of the corporation required by law or by this Certificate of Incorporation, the affirmative vote of the holders of at least sixty-six and two-thirds percent (66 2/3%) of the voting power of all of the then-outstanding shares of the capital stock of the corporation entitled to vote generally in the election of directors, voting together as a single class, shall be required to adopt, amend or repeal any provision of the Bylaws of the corporation.

2. The directors of the corporation need not be elected by written ballot unless the Bylaws so provide.

3. No action shall be taken by the stockholders of the corporation except at an annual or special meeting of stockholders called in accordance with the Bylaws or by written consent or electronic transmission of stockholders in accordance with the Bylaws prior to the closing of the Initial Public Offering and following the closing of the Initial Public Offering no action shall be taken by the stockholders by written consent or electronic transmission.

4. Advance notice of stockholder nominations for the election of directors and of business to be brought by stockholders before any meeting of the stockholders of the corporation shall be given in the manner provided in the Bylaws of the corporation.

VI.

A. The liability of the directors for monetary damages shall be eliminated to the fullest extent under applicable law. If the DGCL is amended to authorize corporate action further eliminating or limiting the personal liability of directors, then the liability of a director of the corporation shall be eliminated to the fullest extent permitted by the DGCL, as so amended.

B. Any repeal or modification of this Article VI shall be prospective and shall not affect the rights under this Article VI in effect at the time of the alleged occurrence of any act or omission to act giving rise to liability or indemnification.

VII.

A. The corporation reserves the right to amend, alter, change or repeal any provision contained in this Certificate of Incorporation, in the manner now or hereafter prescribed by statute, except as provided in paragraph B. of this Article VII, and all rights conferred upon the stockholders herein are granted subject to this reservation.

B. Notwithstanding any other provisions of this Certificate of Incorporation or any provision of law which might otherwise permit a lesser vote or no vote, but in addition to any affirmative vote of the holders of any particular class or series of the corporation required by law or by this Certificate of Incorporation or any certificate of designation filed with respect to a series of Preferred Stock, the affirmative vote of the holders of at least sixty-six and two-thirds percent (66-2/3%) of the voting power of all of the then-outstanding shares of capital stock of the corporation entitled to vote generally in the election of directors, voting together as a single class, shall be required to alter, amend or repeal Articles V, VI and VII.

IN WITNESS WHEREOF, the undersigned has caused this Restated Certificate of Incorporation to be duly executed on behalf of the Corporation on July 3, 2006.


	REPLIDYNE, INC.
	By:	/s/ Kenneth J. Collins
		Kenneth J. Collins
		President and Chief Executive Officer