<PAGE>
 
                                                                   Exhibit 10.20


                        DEPUY, INC.
                        RETIREMENT EXCESS PLAN
                        (As Amended and in Effect as of
                        October 1, 1996)
<PAGE>
 
DEPUY, INC.
RETIREMENT EXCESS PLAN
(As Amended and in Effect as of October 1, 1996)



<TABLE>
<CAPTION>
CONTENTS  
----------------------------------------------------------------- 
SECTION                                                      PAGE
<S>       <C>                                                 <C>
          ARTICLE I. ESTABLISHMENT OF THE PLAN
  1.1     Establishment and Restatement.                       1
  1.2     Purpose of Plan.                                     1

          ARTICLE II. DEFINITIONS AND CONSTRUCTION
  2.1     Definitions.                                         2
  2.2     Gender and Number.                                   2
  2.3     Employment Rights.                                   2
  2.4     Applicable Law.                                      2

          ARTICLE III. ADMINISTRATION           
  3.1     Administration.                                      3
  3.2     Finality of Determination.                           3
  3.3     Indemnification and Exculpation.                     3    
                                                
          ARTICLE IV. PARTICIPATION AND BENEFITS
  4.1     Participation.                                       4
  4.2     Establishment of Accounts.                           4
  4.3     Earnings.                                            4
  4.4     Payment of Accounts.                                 4
  4.5     Payments Upon Death.                                 4
                                                
          Article V. Limitations                
  5.1     Vesting.                                             5      
  5.2     Maximum Benefits.                                    5    
</TABLE>
                                       
                                       i

                                       
<PAGE>
 
DePuy, Inc.
Retirement Excess Plan
(As Amended and in Effect as of October 1, 1996)

 
<TABLE>
<CAPTION>
CONTENTS  
----------------------------------------------------------------- 
SECTION                                                      PAGE
<S>       <C>                                               <C>
          ARTICLE VI. MISCELLANEOUS 
  6.1     Amendment and Termination.                            6
  6.2     Funding.                                              6  
  6.3     Tax Liability.                                        6  
  6.4     Assignment.                                           6  
  6.5     Successors.                                           6  
  6.6     Severability.                                         7  
  6.7     Nonuniform Determinations.                            7  
  6.8     Separation From Other Plans.                          7  
  6.9     Effective Date.                                       7  
</TABLE>                                
                        
                                      ii

                                      
<PAGE>
 
ARTICLE I. ESTABLISHMENT OF THE PLAN

1.1 ESTABLISHMENT AND RESTATEMENT.

Boehringer Mannheim U.S. Holdings, Inc. previously established an excess benefit
plan on behalf of itself, its subsidiaries, and other affiliated corporations.
Such plan was adopted, effective as of January 1, 1991, and was originally known
as the "Boehringer Mannheim U.S. Holdings, Inc. Excess Benefit Retirement Plan"
(the "Plan").

The name of the Plan (and Plan sponsor) was subsequently changed, and on
September 30, 1996, the Plan was known as the Corange U.S. Holdings, Inc.
Retirement Excess Plan. Effective as of October 1, 1996, the liabilities under
the Plan which related to Participants employed by Boehringer Mannheim
Corporation or its participating affiliates were spun off and transferred to a
new plan, known as the Boehringer Mannheim Corporation Retirement Excess Plan.
The Plan is hereby renamed and will be known as the DePuy, Inc. Retirement
Excess Plan.

1.2 PURPOSE OF PLAN.

The Company sponsors the DePuy, Inc. Retirement Income Plan (the "RIP Plan"),
for the benefit of U.S. employees of the Employers and their beneficiaries. The
RIP Plan is intended to operate as a "qualified plan" as that term is defined
under the Internal Revenue Code (the "Code").

The RIP Plan is subject to limitations under section 415 of the Code that
sometimes result in the diminution of allocations on behalf of certain
employees. This Plan is established to offset this diminution for eligible
employees, is intended as an unfunded excess benefit plan as defined in section
3(36) of ERISA, and is fully exempt from the provisions of ERISA pursuant to
section 4(b)(5) thereof.


                                       1

                                       
<PAGE>
 
ARTICLE II. DEFINITIONS AND CONSTRUCTION

2.1 DEFINITIONS.

Whenever the following terms are used in this Plan, they shall have the meaning
specified unless a contrary intention is specifically and clearly indicated.
(a)  "ADMINISTRATOR" means the Company.
(b)  "BOARD" means the Board of Directors of the Company.
(c)  "CODE" means the Internal Revenue Code of 1986, as it may be amended from
     time to time. Reference to a section of the Code shall also include any
     comparable provision of the Code that supersedes said section.
(d)  "COMPANY" means DePuy, Inc. an Delaware corporation, or any successor
     corporation resulting from a merger or consolidation with the Company or
     transfer of substantially all of the assets of the Company.
(e)  "EMPLOYER" means the Company and any other entity which is an "Employer" as
     that term is defined in the RIP Plan.
(f)  "PARTICIPANT" means an employee of an Employer who has met the
     participation requirements set forth in section 4.1 of the Plan.
(g)  "PLAN" means this DePuy, Inc. Retirement Excess Plan.

2.2 GENDER AND NUMBER.

Except when otherwise indicated by the context, words in the masculine gender
shall include the feminine and neuter genders; the plural shall include the
singular and the singular shall include the plural.

2.3 EMPLOYMENT RIGHTS.

Establishment of the Plan shall not be construed to give any Participant the
right to be retained in the employment of an Employer or to any benefits not
specifically provided by the Plan.

2.4 APPLICABLE LAW.

This Plan provides benefits limited by Section 415 of the Code; therefore, it is
fully exempt from the provisions of ERISA pursuant to Section 4(b)(5) thereof
and shall be governed and construed in accordance with the laws of the State of
Indiana.


                                       2

                                       
<PAGE>
 
ARTICLE III. ADMINISTRATION

3.1 ADMINISTRATION.

Except as specifically provided elsewhere in the Plan, the Administrator shall
have all such powers as may be necessary to carry out the provisions of the Plan
and the transaction of the Plan's business. The authority granted under this
Article shall be subject to the right of the Board to amend or terminate the
Plan, as provided in section 8.1.

3.2 FINALITY OF DETERMINATION.

The determination of the Administrator as to any disputed questions arising
under this Plan, including questions of construction and interpretation shall be
final, binding, and conclusive upon all persons.

3.3 INDEMNIFICATION AND EXCULPATION.

Any individual who is directed by the Company to carry out responsibilities or
duties imposed by the Plan shall be indemnified and held harmless by the Company
against and from any and all loss, cost, liability, or expense that may be
imposed upon or reasonably incurred by them in connection with or resulting from
any claim, action, suit, or proceeding to which they may be a party or in which
they may be involved by reason of any action taken or failure to act under this
Plan and against and from any and all amounts paid by them in settlement (with
the Company's written approval) or paid by them in satisfaction of a judgment in
any such action, suit, or proceeding. The foregoing provision shall not be
applicable to any person if the loss, cost, liability, or expense is due to such
person's gross negligence or willful misconduct.


                                       3

                                       
<PAGE>
 
ARTICLE IV. PARTICIPATION AND BENEFITS

4.1 PARTICIPATION.

An employee will become eligible to participate in this Plan on the first day of
a year following any calendar year in which the amounts allocable to his account
under the RIP Plan are limited by the defined contribution limit under section
415(c)(1) of the Code. Notwithstanding the preceding sentence, no Employer
contributions shall be credited to the account of an employee during a calendar
year in which the employee is a participant in another nonqualified retirement
plan sponsored by any Employer.

4.2 ESTABLISHMENT OF ACCOUNTS.

The Company shall establish an account on its books on behalf of each
Participant in this Plan. A Participant's account will be credited with the
employer contribution that would have been credited to his account under the RIP
Plan if the contributions to the RIP Plan were not limited by the defined
contribution limit under section 415(c)(1) of the Code, reduced by the employer
contribution actually credited to his account under the RIP Plan.

4.3 EARNINGS.

The account established for each Participant pursuant to section 4.2 shall be
adjusted to reflect an assumed rate of earnings. Such rate shall be the rate of
earnings achieved by the GIC Fund maintained under the RIP Plan.

4.4 PAYMENT OF ACCOUNTS.

The account established for each Participant under section 4.2, increased for
earnings under section 4.3, shall be payable to the Participant when such
Participant becomes eligible to receive benefits under the RIP Plan. The account
shall be paid in a single lump sum payment.

4.5 PAYMENTS UPON DEATH.

Each Participant shall have the right to designate a beneficiary to receive
death benefits under this Plan. In the absence of such a designation, the
beneficiary of the Participant under the RIP Plan will be the beneficiary of the
Participant's benefits under this Plan. In the event of a Participant's death
prior to the payment of benefits under section 4.4, the Participant's
beneficiary shall receive the balance in the Participant's account under section
4.3 in a single lump sum payment as soon as practicable following the death of
the Participant.


                                       4

                                       
<PAGE>
 
ARTICLE V. LIMITATIONS

5.1 VESTING.

Notwithstanding anything to the contrary in Article IV, a Participant shall
forfeit any portion of his account under this Plan (and any earnings thereon) if
the Participant's employment with the Company and all affiliates terminates
before the Participant completes five years of service with the Company.

5.2 MAXIMUM BENEFITS.

The maximum amount allocable to a Participant under section 4.2 for any single
calendar year shall be $10,000.


                                       5

                                       
<PAGE>
 
ARTICLE VI. MISCELLANEOUS

6.1 AMENDMENT AND TERMINATION.

The Board may at any time terminate or amend the Plan in any respect. A
termination or amendment of the Plan shall not, without the written consent of a
Participant, adversely affect the rights of the Participant with respect to
amounts credited to the Participant's account under Article V prior to such
termination or amendment.

6.2 FUNDING.

All amounts paid under this Plan shall be paid in cash from the general assets
of the Employer, unless paid from a grantor trust established under section 671
of the Code. Such amounts shall be reflected on the accounting records of the
Employer but shall not be construed to create, or require the creation of, a
trust, custodial or escrow account. No employee shall have any right, title or
interest whatever in or to any investment reserves, accounts or funds that the
Employer may purchase, establish or accumulate to aid in providing the benefits
under this Plan. Nothing contained in this Plan, and no action taken pursuant to
its provisions, shall create a trust or fiduciary relationship of any kind
between the Employer and an employee or any other person. Neither an employee or
beneficiary of an employee shall acquire any interest greater than that of an
unsecured creditor.

6.3 TAX LIABILITY.

The Company may withhold, or direct the withholding of, from any payment of
benefits hereunder any taxes required to be withheld and such sum as the Company
may reasonably estimate to be necessary to cover any taxes for which the Company
may be liable and which may be assessed with regard to such payment.

6.4 ASSIGNMENT.

The Participant may not assign, pledge, or otherwise transfer or encumber any of
Participant's benefits under this Plan.

6.5 SUCCESSORS.

The Plan and the rights and obligations of the company hereunder shall be
binding upon, and inure to the benefit of the Participants and their
beneficiaries only, and the successors and assigns of the Company.


                                       6

                                       
<PAGE>
 
6.6 SEVERABILITY.

In the event that any one or more of the provisions of this Plan shall be held
to be invalid, illegal, or unenforceable, the validity, legality, or
enforceability of the remaining provisions shall not in any way be affected or
impaired thereby.

6.7 NONUNIFORM DETERMINATIONS.

The determinations of the Administrator under the Plan need not be uniform and
may be made selectively among Participants who receive, or are eligible to
receive, benefits under the Plan, whether or not such Participants are similarly
situated. Such determinations, however, may not result in payment to a
Participant of an amount that is less than the amount that is otherwise provided
for under the terms of this Plan.

6.8 SEPARATION FROM OTHER PLANS.

Except as otherwise required by law, no benefits under the Plan shall be taken
into account in determining any benefit under any other pension, retirement,
thrift, profit sharing, 401(k), group insurance, or other benefit plan
maintained or hereafter established by the Company.

6.9 EFFECTIVE DATE.

This Plan, as initially adopted, is effective as of January 1, 1991.

                              * * * * * * * * * *

IN WITNESS WHEREOF, DePuy, Inc. has caused this instrument to be executed by its
duly authorized officers on this 31 day of December, 1996, effective as
of the 1st day of October, 1996.

                                                DEPUY, INC.
ATTEST:
                                                By /s/ G. Taylor Seward
                                                   ____________________________

By /s/ Carol Hadley
   _________________________



                                       7