Exhibit 10.15

Pages or exhibits where confidential treatment has been requested are stamped 
"Confidential portions omitted and filed separately with the Commission."  The 
appropriate section has been marked at the appropriate place with an "*".
 
                     AMENDMENT TO SECOND LICENSE AGREEMENT

     This AMENDMENT TO SECOND LICENSE AGREEMENT is made and entered into
effective as of the 25th day of March, 1985, by and between Biomedical
Engineering Trust, successor in interest to Biomedical Engineering Corp., whose
address is c/o 153 Irvington Avenue, South Orange, New Jersey 07079 (hereinafter
referred to as LICENSOR) and DePuy, Division of Boehringer Mannheim Corporation,
successor to DePuy Division of BioDynamics, Inc., whose Post Office address is
P.O. Box 988, Warsaw, Indiana 46580 (hereinafter referred to as LICENSEE),

                                  WITNESSETH:
                                  ----------

     WHEREAS LICENSOR and LICENSEE entered into a LICENSE AGREEMENT dated April
25, 1977, and amended December 9, 1977 (hereinafter referred to as "FIRST
LICENSE AGREEMENT"), which FIRST LICENSE AGREEMENT was cancelled in favor of a
novation denominated SECOND LICENSE AGREEMENT effective as of July 24, 1979; and

     WHEREAS LICENSOR and LICENSEE agree that certain aspects of the 
relationships between LICENSOR and LICENSEE must be defined and clarified; and

     WHEREAS LICENSOR and LICENSEE agree that the following amendments to the
SECOND LICENSE AGREEMENT will clarify the relationship between the parties as of
the date hereof;


 
        NOW, THEREFORE, in view of the foregoing premises and the following 
mutual covenants, the adequacy and sufficiency of which as consideration are 
hereby acknowledged, the parties hereby agree as follows:

A.      Paragraph 2 of the SECOND LICENSE AGREEMENT shall be and is hereby 
deleted and new Paragraph 2 shall be and hereby is substituted therefor as
follows:

        2(a).  LICENSEE agrees to pay LICENSOR earned royalty at the rate of * 
percent (* %) of the "sales price" (as defined below) of each of said Floating 
Center Shoulder Prosthesis, Surface Replacement Shoulder, Trunion Ankle, and 
Sliding Bearing Ankle and modifications thereof, and * percent (* %) of the 
sales price of each of said N.J. Knee or components therefor and of the sales 
price for Instruments therefor.  However, with respect to the sale of 
porous-coated components of the N.J. Knee occurring in the United States of 
America prior to January 1, 1986, earned royalties shall be discounted such as
to be earned at the rate of * percent (*%) of * (*) of the sales price of each
such porous-coated component. In no event shall the discount as to porous-coated
components for the N.J. Knee extend beyond January 1, 1986.

         (b).  For purposes of this Agreement, the terms "sales price" as to 
sales in the * shall mean the * 

         however, *.


* Confidential portions omitted and filed separately with the Commission.


 

*                                             , the sales price shall be the 
          *                                                         LICENSOR 
agrees that where compensation is received neither by LICENSEE, nor a 
sub-licensee, nor a distributor nor any other person from the sale or transfer 
of any component or instrument, no royalties shall be paid to LICENSOR.

        (c).    For purposes of this Agreement, the term "sales price"
as to sales                      *                               shall mean the 
                                 *
                                  
                            A

                                 *

        (d).    All royalty payments shall be made quarterly in accordance with 
Paragraph 4 below.

B.      The parties agree that with respect to sales occurring prior to the 
effective date of this agreement, an accounting shall be conducted, particularly
with respect to sales outside the United States of America and sales of 
instruments, to determine such royalties as may presently be due and payable to 
LICENSOR calculated based upon the foregoing.

C.      In the first line of Paragraph 5 of the SECOND LICENSE AGREEMENT, delete
"* price" and insert --sales price-- therefor.

* Confidential portions omitted and filed separately with the Commission.

 
WITNESS:                                BIOMEDICAL ENGINEERING TRUST


[Signature appears here]                By /s/ Frederick F. Bruchel
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WITNESS:                                BIOMEDICAL ENGINEERING TRUST


[Signature appears here]                By /s/ Michael J. Pappas
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WITNESS:                                DePUY



[Signature appears here]                By /s/ James A. Lent
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