SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G
(Amendment No. 4)

Under the Securities Exchange Act of 1934


Replidyne, Inc.
(Name of Issuer)


Common Stock, $0.001 par value
(Title of Class of Securities)


76028W107
(CUSIP Number)


December 31, 2008
(Date of Event Which Requires Filing of this Statement)

Check the following box to designate the rule pursuant to which the Schedule is filed:
 
o 
Rule 13d-1(b)
x
Rule 13d-1(c)
o 
Rule 13d-1(d)
 
*The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).
 
 
CUSIP No. 76028W107
  
   
 
1.
Names of Reporting Persons
I.R.S. Identification Nos. of above persons (entities only)
D. E. Shaw Valence Portfolios, L.L.C.
13-4046559
  
       
 
2.
Check the Appropriate Box if a Member of a Group (See Instructions)
 
   
(a)
o 
  
   
(b)
o 
  
         
 
3.
SEC Use Only
 
       
 
4.
Citizenship or Place of Organization
Delaware
  
       
Number of
Shares
Beneficially
Owned by
Each
Reporting
Person With
5.
Sole Voting Power
-0-
  
       
     
6.
Shared Voting Power
24,553
  
           
     
7.
Sole Dispositive Power
-0-
  
           
     
8.
Shared Dispositive Power
24,553
  
           
 
9.
Aggregate Amount Beneficially Owned by Each Reporting Person
24,553
  
       
 
10.
Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) o 
 
  
       
 
11.
Percent of Class Represented by Amount in Row (9)
0.1%
  
       
 
12.
Type of Reporting Person (See Instructions)
OO
  
 
 
CUSIP No. 76028W107
 
 
1.
Names of Reporting Persons
I.R.S. Identification Nos. of above persons (entities only)
D. E. Shaw & Co., L.P.
13-3695715
     
 
2.
Check the Appropriate Box if a Member of a Group (See Instructions)
   
(a)
o 
   
(b)
o 
       
 
3.
SEC Use Only
     
 
4.
Citizenship or Place of Organization
Delaware
     
Number of
Shares
Beneficially
Owned by
Each
Reporting
Person With
5.
Sole Voting Power
-0-
     
     
6.
Shared Voting Power
24,553
         
     
7.
Sole Dispositive Power
-0-
         
     
8.
Shared Dispositive Power
24,553
         
 
9.
Aggregate Amount Beneficially Owned by Each Reporting Person
24,553
     
 
10.
Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) o 
 
     
 
11.
Percent of Class Represented by Amount in Row (9)
0.1%
     
 
12.
Type of Reporting Person (See Instructions)
IA, PN


CUSIP No. 76028W107
  
   
 
1.
Names of Reporting Persons
I.R.S. Identification Nos. of above persons (entities only)
David E. Shaw
  
       
 
2.
Check the Appropriate Box if a Member of a Group (See Instructions)
 
   
(a)
o 
  
   
(b)
o 
  
         
 
3.
SEC Use Only
 
       
 
4.
Citizenship or Place of Organization
United States
  
       
Number of
Shares
Beneficially
Owned by
Each
Reporting
Person With
5.
Sole Voting Power
-0-
  
       
     
6.
Shared Voting Power
24,553
  
           
     
7.
Sole Dispositive Power
-0-
  
           
     
8.
Shared Dispositive Power
24,553
  
           
 
9.
Aggregate Amount Beneficially Owned by Each Reporting Person
24,553
  
       
 
10.
Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) o 
 
  
       
 
11.
Percent of Class Represented by Amount in Row (9)
0.1%
  
       
 
12.
Type of Reporting Person (See Instructions)
IN
  
 
 
Item 1.
 
(a) 
Name of Issuer: 
   
     Replidyne, Inc.
 
 
  
 
(b) 
Address of Issuer's Principal Executive Offices: 
   
1450 Infinite Drive
Louisville, CO 80027
 
Item 2.
 
(a) 
Name of Person Filing: 
   
D. E. Shaw Valence Portfolios, L.L.C.
D. E. Shaw & Co., L.P.
David E. Shaw
     
 
(b) 
Address of Principal Business Office or, if none, Residence: 
   
The business address for each reporting person is:
120 W. 45th Street, Tower 45, 39th Floor
New York, NY 10036
     
 
(c) 
Citizenship: 
   
D. E. Shaw Valence Portfolios, L.L.C. is a limited liability company organized under the laws of the state of Delaware.
D. E. Shaw & Co., L.P. is a limited partnership organized under the laws of the state of Delaware.
David E. Shaw is a citizen of the United States of America.
     
 
(d) 
Title of Class of Securities: 
   
   Common Stock, $0.001 par value
     
 
(e) 
CUSIP Number: 
   
76028W107
 
Item 3.
If this statement is filed pursuant to Rule 13d-1(b) or 13d-2(b) or (c), check whether the person filing is a:
 
Not Applicable
 
Item 4.
Ownership
   
As of December 31, 2008:
  
   
(a) Amount beneficially owned:
  
   
    D. E. Shaw Valence Portfolios, L.L.C.:
24,553 shares
   
D. E. Shaw & Co., L.P.:
24,553 shares
This is composed of 24,553 shares in the name of D. E. Shaw Valence Portfolios, L.L.C.
   
David E. Shaw: 
24,553 shares
This is composed of 24,553 shares in the name of D. E. Shaw Valence Portfolios, L.L.C.
 
 
(b) Percent of class: 
 
   D. E. Shaw Valence Portfolios, L.L.C.:
0.1%
D. E. Shaw & Co., L.P.:
0.1%
David E. Shaw: 
0.1%
     
(c) Number of shares to which the person has: 
  
(i) 
Sole power to vote or to direct the vote: 
  
     D. E. Shaw Valence Portfolios, L.L.C.:
-0- shares 
 
D. E. Shaw & Co., L.P.: 
-0- shares 
 
David E. Shaw: 
-0- shares 
     
(ii) 
Shared power to vote or to direct the vote: 
  
     D. E. Shaw Valence Portfolios, L.L.C.:
24,553 shares
 
D. E. Shaw & Co., L.P.: 
24,553 shares
 
David E. Shaw: 
24,553 shares
     
(iii) 
Sole power to dispose or to direct the disposition of: 
  
     D. E. Shaw Valence Portfolios, L.L.C.:
-0- shares 
 
D. E. Shaw & Co., L.P.: 
-0- shares 
 
David E. Shaw: 
-0- shares 
     
(iv) 
Shared power to dispose or to direct the disposition of: 
  
     D. E. Shaw Valence Portfolios, L.L.C.:
24,553 shares
 
D. E. Shaw & Co., L.P.: 
24,553 shares
 
David E. Shaw: 
24,553 shares

David E. Shaw does not own any shares directly. By virtue of David E. Shaw’s position as President and sole shareholder of D. E. Shaw & Co., Inc., which is the general partner of D. E. Shaw & Co., L.P., which in turn is the managing member and investment adviser of D. E. Shaw Valence Portfolios, L.L.C., David E. Shaw may be deemed to have the shared power to vote or direct the vote of, and the shared power to dispose or direct the disposition of, the 24,553 shares as described above constituting 0.1% of the outstanding shares and, therefore, David E. Shaw may be deemed to be the beneficial owner of such shares. David E. Shaw disclaims beneficial ownership of such 24,553 shares.
 
Item 5.
Ownership of Five Percent or Less of a Class
If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than 5 percent of the class of securities, check the following [X].
 
Item 6.
Ownership of More than Five Percent on Behalf of Another Person
Not Applicable
 
Item 7.
Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company or Control Person
Not Applicable
 
Item 8.
Identification and Classification of Members of the Group
Not Applicable
 
Item 9.
Notice of Dissolution of Group
Not Applicable
 
Item 10.
Certification
By signing below, each of D. E. Shaw Valence Portfolios, L.L.C., D. E. Shaw & Co., L.P., and David E. Shaw certify that, to the best of such reporting person’s knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having such purposes or effect.
SIGNATURE
 
After reasonable inquiry and to the best of their knowledge and belief, the undersigned certify that the information set forth in this statement is true, complete and correct.  A Power of Attorney, dated October 24, 2007, granted by David E. Shaw in favor of Rochelle Elias, is attached hereto.

Dated: February 17, 2009
       
 
D. E. Shaw Valence Portfolios, L.L.C.  
  By:
D. E. Shaw & Co., L.P., as
    managing member
 
 		  
 		    
 
    
By: 
 /s/ Rochelle Elias
   
Rochelle Elias
Chief Compliance Officer
 
     
  D. E. Shaw & Co., L.P.
 
 		  
 		  
 
  By:    /s/ Rochelle Elias
 
Rochelle Elias
Chief Compliance Officer
 
     
  David E. Shaw
 
 		  
 		  
 
  By:    /s/ Rochelle Elias
 
Rochelle Elias
Attorney-in-Fact for David E. Shaw