6


                                                                 EXHIBIT 10(xvi)

                                 Amendment No. 1

                                       to

                       Stock and Asset Purchase Agreement
                       ----------------------------------

         AMENDMENT  No. 1, dated as of October 22, 1998 (this  "Amendment"),  to
the STOCK AND ASSET PURCHASE AGREEMENT,  dated as of August 13, 1998 (the "Stock
and Asset  Purchase  Agreement"),  between  Pfizer Inc., a Delaware  corporation
("Pfizer"), and Stryker Corporation, a Michigan corporation ("Stryker").

                               W I T N E S S E T H
                               - - - - - - - - - -

         WHEREAS,  Pfizer  and  Stryker  desire  to amend  the  Stock  and Asset
Purchase Agreement in certain respects as more fully set forth below.

         NOW,   THEREFORE,   in   consideration  of  the  mutual  covenants  and
undertakings  contained  herein,  and subject to and on the terms and conditions
set forth, the parties hereto agree as follows:

         Section  1.  Capitalized  terms  used in this  Amendment  that  are not
otherwise  defined herein shall have the meanings  ascribed to such terms in the
Stock and Asset Purchase Agreement.

         Section 2.   The Stock and Asset Purchase Agreement shall be amended as
                      follows:

         2.1    Section 2.7 shall be amended to read in its entirety as follows:

                           "Section 2.7 PURCHASE PRICE.  (a) In consideration of
                   the sale and transfer of the Shares and the sale and transfer
                   of the Conveyed  Assets,  Purchaser  shall pay to Pfizer,  as
                   agent for the Seller  Corporations (or to Pfizer's Affiliates
                   as Pfizer may on behalf of the Seller  Corporations direct in
                   the written transfer  instructions  hereinafter referred to),
                   an aggregate  amount of One Billion Six Hundred Fifty Million
                   Dollars  ($1,650,000,000.00)  (the "Aggregate  Payment"),  in
                   immediately  available  funds, by wire transfer in accordance
                   with written  instructions  given by Pfizer to Purchaser  not
                   less than two (2) Business  Days prior to the Closing,  which
                   consideration   shall  be  subject  to  the  purchase   price
                   adjustment provided for in Section 2.8 and shall be allocated
                   as described below.

                           (b) In  consideration of the sale and transfer of the
                   Shares,  Purchaser  agrees to purchase from the Stock Selling
                   Corporations  the Shares for an aggregate  purchase  price of
                   Five Hundred  Twenty-Four Million One Hundred Eighty Thousand
                   Dollars  ($524,180,000.00),  allocated  among  the  Shares as
                   described in Schedule 2.9 (the "Share Purchase Price").





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                           (c) In  consideration of the sale and transfer of the
                   Conveyed  Assets,  the Purchaser agrees to purchase from each
                   Asset Selling  Corporation  the Conveyed Assets owned by such
                   Asset Selling  Corporation for an aggregate purchase price of
                   One Billion One Hundred  Twenty-Five  Million  Eight  Hundred
                   Twenty Thousand Dollars ($1,125,820,000.00),  allocated among
                   the Asset  Selling  Corporations  as described in Section 2.9
                   (the  "Asset  Purchase  Price" and,  together  with the Share
                   Purchase Price, the "Aggregate Purchase Price")."

                  2.2 The last  sentence of  Section  2.9 shall  be  deleted and
                      replaced by the following:

                           "If after all other adjustments to the Allocation are
                   made,  the  Allocation  with  respect  to any  Asset  Selling
                   Corporation  or Conveyed  Subsidiary  (or  Subsidiary),  when
                   expressed  in the  relevant  local  currency  at the  rate of
                   exchange  used to determine  Final Working  Capital,  is less
                   than  the  local  currency  net  book  value,  determined  in
                   accordance  with GAAP,  of the Conveyed  Assets of such Asset
                   Selling Corporation or the assets of such Conveyed Subsidiary
                   (or  Subsidiary) as of the Closing Date,  then the Allocation
                   with respect to such Asset  Selling  Corporation  or Conveyed
                   Subsidiary  (or  Subsidiary)  shall be adjusted so that it is
                   equal to such local currency net book value  converted at the
                   rate of exchange used to determine  Final Working Capital and
                   a  corresponding  adjustment  will be made,  as to the  first
                   $3,000,000, to the Allocation with respect to Howmedica Inc.,
                   and as to any balance in excess of the first  $3,000,000,  to
                   the Allocation with respect to Howmedica GmbH."

                  2.3 Schedule 2.9 shall be amended and replaced in its entirety
                      by the Schedule 2.9 attached hereto as Annex A.

                  2.4 Section 4.2(c) shall be amended to read in its entirety as
                      follows:

                           "(c) Purchaser  shall have received funds pursuant to
                   the credit facilities  provided for in the commitment letter,
                   dated October 22, 1998, between  Purchaser,  on the one hand,
                   and  Goldman  Sachs  Credit  Partners  L.P.,  Bank of America
                   National  Trust  and  Savings   Association  and  Nationsbanc
                   Montgomery  Securities  LLC (the  "Arrangers")  on the  other
                   hand,  a copy of which  has been  furnished  to  Pfizer  (the
                   "Financing  Commitment  Letter").   The  parties  agree  that
                   Purchaser's  ability  to rely on the  condition  set forth in
                   this Section  4.2(c) is subject to the  provisions of Section
                   7.3(d) hereof."

                  2.5 Section 7.3(d) shall be amended to read in its entirety as
                      follows:

                           "(d)  Purchaser  shall use its best  efforts to cause
                   the  conditions  to funding  under the  Financing  Commitment
                   Letter  to be  satisfied  and to borrow  the  funds  provided
                   thereunder. Notwithstanding the foregoing, and subject to the
                   following provisions of this Section 7.3(d),  Purchaser shall
                   not  be  required  to  borrow   funds  under  the   Financing
                   Commitment Letter if the Arrangers notify





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                    Purchaser in writing (the "Arrangers' Notice") that pursuant
                    to the Financing  Commitment  Letter,  they have  determined
                    that changes in the tranche  amounts or interest rate margin
                    are  necessary  and such changes cause the weighted  average
                    Applicable Eurodollar Rate Margin determined as set forth in
                    the  Financing  Commitment  Letter on the credit  facilities
                    (including the  refinancing of the Japanese Yen  denominated
                    indebtedness  in the  amount of  approximately  $75  million
                    provided  for  therein)  to exceed  3.05 per cent per annum.
                    Purchaser  will  keep  Pfizer  informed  of  the  status  of
                    discussions  regarding  pricing  of the loans from and after
                    the date hereof and will notify Pfizer of its receipt of any
                    Arrangers'  Notice  within 24 hours and will provide  Pfizer
                    with a copy  thereof  and the  calculation  of the  weighted
                    average   Applicable    Eurodollar   Rate   Margin   and   a
                    determination  of the amount  thereof  that exceeds 3.05 per
                    cent per annum (such amount in excess of 3.05 per cent being
                    referred to as the "Maximum Excess Margin").  In such event,
                    Pfizer  shall  have the right (but not the  obligation),  by
                    notice  to  Purchaser  within 2  Business  Days of  Pfizer's
                    receipt  of any  Arrangers'  Notice,  to  elect  to bear and
                    reimburse  Purchaser on a quarterly basis an amount equal to
                    the portion of the weighted  average  Applicable  Eurodollar
                    Rate Margin which  accrued on the credit  facilities  during
                    that quarter that exceeds 3.05 per cent per annum, but in no
                    event shall Pfizer be responsible  for more than the Maximum
                    Excess  Margin.  If Pfizer  makes such  election,  Purchaser
                    shall be required  to borrow the funds  under the  Financing
                    Commitment  Letter unless the Maximum  Excess Margin exceeds
                    .25 per  cent,  in which  case  Purchaser  may  elect not to
                    borrow the funds  regardless of whether  Pfizer has made the
                    election  referred  to  above.  Within 15 days of the end of
                    each quarter,  Purchaser  will provide Pfizer with a written
                    statement of the amounts  outstanding  under each tranche of
                    the credit  facilities during the quarter and the Applicable
                    Eurodollar  Rate Margins  together with a calculation of the
                    weighted average  Applicable  Eurodollar Rate Margin accrued
                    during such  quarter and the amount  payable by Pfizer under
                    this  Section  7.3(d).  Pfizer  shall  pay  such  amount  to
                    Purchaser   within  5  Business  Days  of  receipt  of  such
                    statement from the Purchaser. Pfizer shall have no liability
                    to reimburse Purchaser for any additional interest which may
                    result  from  any  changes  in or  waivers  of the  terms of
                    payment under the credit facilities provided pursuant to the
                    Financing  Commitment  Letter after Pfizer's  election under
                    this Section 7.3(d) has been made,  whether such  additional
                    interest  results as a  consequence  of changes in  interest
                    rates  or  spreads,  refinancing,  default,  changes  in the
                    amounts  and timing of payments or  otherwise  (whether  any
                    such change is permitted by the original terms of the credit
                    agreement or results from subsequent modifications agreed to
                    by the lenders and Purchaser)."

                  Section 3.  REFERENCES.  All references to "this Agreement" 
                  in the Stock and Asset Purchase Agreement shall mean the Stock
                  and Asset Purchase Agreement as amended hereby.

                  Section 4.  GOVERNING LAW.  This Amendment shall be governed 
                  by the laws of the State of New York, its rules of conflict 
                  of laws notwithstanding.





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                  Section 5. COUNTERPARTS. This Amendment may be executed in one
                  or more  counterparts,  each  of  which  shall  be  deemed  an
                  original,  and all of which shall  constitute one and the same
                  agreement.

                  Section 6. NO OTHER  AMENDMENTS.  Except as expressly  amended
                  hereby,  the  terms  and  conditions  of the  Stock  and Asset
                  Purchase Agreement shall continue in full force and effect.

                  IN WITNESS  WHEREOF,  the parties have executed or caused this
Amendment to be executed as of the date first written above.

                                   PFIZER INC.


                                      By:
                                          ----------------------------------
                                               Name:
                                               Title:


                                      STRYKER CORPORATION


                                      By:
                                          ----------------------------------
                                              Name:
                                              Title:





                                  SCHEDULE 2.9
                   SECTION 2.9(i) Allocation of Purchase Price

      Allocation Among Conveyed Subsidiaries and Asset Selling Corporations




                         CONVEYED SUBSIDIARIES
                                                                                                
Howmedica International Inc. (Panama)                                             $160,571,000
Benoist Girard & Cie S.C.A (France)                                                 95,776,000
Howmedica Leibinger Inc. (Delaware)                                                 85,105,000
Howmedica GmbH (Germany)                                                            59,391,000
Howmedica Leibinger GmbH & Co. KG (Germany)1                                        64,524,000
Jaquet Orthopedie S.A. (Switzerland)                                                21,100,000
Howmedica Iberica S.A. (Spain)                                                      22,579,000
Pficonprod Pty Ltd. (Australia)                                                     15,134,000
                                                                                   -----------
                                         SUBTOTAL CONVEYED SUBSIDIARIES                               $  524,180,000

                           ASSET SELLING CORPORATIONS
Howmedica Inc. (US)                                                               $736,697,000
Pfizer Seiyaku K.K. (Japan)                                                        148,639,000
Pfizer Italiana S.p.A (Italy)                                                       67,100,000
Howmedica France S.C.A. (France)                                                    39,947,000
Howmedica International Limited (U.K.)                                              27,008,000
Pfizer Canada Inc. (Canada)                                                         17,716,000
Pfizer Medical Technology Group A.B. (Sweden)                                       12,298,000
Pfizer Medical Technology Group (Netherlands) B.V.                                  11,061,000
Pfizer Medical Technology Group Ltd. (U.K.)                                         12,558,000
Pfizer Hellas A.E. (Greece)                                                         12,116,000
Roerig Farmaceutici Italiana S.p.A. (Italy)                                         10,076,000
Pfizer Medical Technology Group (Belgium) N.V.                                       6,861,000
Pfizer Corporation (Panama) Puerto Rico Branch                                       6,253,000
Pfizer Laboratories Ltd. (New Zealand)                                               4,863,000
Pfizer Limited (Taiwan)                                                              3,474,000
Laboratorios Pfizer Ltda. (Brazil)                                                   1,824,000
Laboratorios Pfizer Ltda. (Portugal)                                                 1,737,000
Howmedica Handelsgesellschaft m.b.H (Austria)                                        1,476,000
Duchem Laboratories Ltd. (India)                                                     1,216,000
Pfizer Oy (Finland)                                                                  1,138,000
Pfizer A/S (Denmark)                                                                   894,000
Pfizer Medical Technology Group A.B. (Sweden) Norway Branch                            521,000
Pfizer Laboratories (Proprietary) Ltd. (South Africa)                                  347,000
                                                                                   -----------
                       SUBTOTAL ASSET SELLING CORPORATIONS                                             1,125,820,000
                                                                                                      --------------


                         TOTAL PURCHASE PRICE ALLOCATION                                              $1,650,000,000
                                                                                                      ==============


- --------
1 Subsidiary of Conveyed Subsidiary Howmedica GmbH (Germany)