<PAGE>   1
                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                                 ---------------

                                  FORM 10-K/A

[X]      ANNUAL REPORT UNDER SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT 
         OF 1934

         FOR THE FISCAL YEAR ENDED DECEMBER 31, 1998

                                       OR

[ ]     TRANSITION REPORT UNDER SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE 
        ACT OF 1934

                         Commission file number 0-23165

                                   RENEX CORP.

             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

                                 ---------------

                  FLORIDA                                    65-0422087
      (STATE OR OTHER JURISDICTION OF                     (I.R.S. EMPLOYER
       INCORPORATION OR ORGANIZATION)                  IDENTIFICATION NUMBER)

                                 ---------------

           201 Alhambra Plaza, Suite 800, Coral Gables, Florida 33134
          (ADDRESS OF PRINCIPAL EXECUTIVE OFFICES, INCLUDING ZIP CODE)
        Registrant's telephone number including area code: (305) 448-2044

           Securities Registered Pursuant to Section 12(b) of the Act:
                                      None

           Securities Registered Pursuant to Section 12(g) of the Act:
                          Common Stock, $.001 par value

-------------------------------------------------------------------------------
                                (TITLE OF CLASS)

    Indicate by check mark whether the registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the past 12 months (or for such shorter period that the registrant
was required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days. [ X] Yes [ ] No

    Indicate by check mark if disclosure of delinquent filers pursuant to Item
405 of Regulation S-K is not contained in this form, and no disclosure will be
contained, to the best of the registrant's knowledge, in definitive proxy or
information statements incorporated by reference in Part III of this Form 10-K
or any amendment to this Form 10-K. [ X ]

    The aggregate market value of Renex Corp. Common Stock, $.001 par value held
by non-affiliates of the Company was $24,745,505 as of March 22, 1999 based upon
the closing sales price of the Common Stock as reported on the Nasdaq National
Market System on such date.

    Number of shares of Common Stock of Renex Corp. outstanding as of March 22,
1999: 7,252,466

                       DOCUMENTS INCORPORATED BY REFERENCE

                                      None


<PAGE>   2



                                   SIGNATURES

    Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the registrant has duly caused this report to be signed on
behalf of the undersigned, thereunto duly authorized.


                                    RENEX CORP.



Date: MARCH 29, 1999                By: /s/ James P. Shea
                                        ---------------------------------------
                                           James P. Shea
                                           PRESIDENT AND CHIEF EXECUTIVE OFFICER

    Pursuant to the requirements of the Securities Exchange Act of 1934, this
report has been signed below by the following persons on behalf of the
registrant and in the capacities and on the dates indicates.

<TABLE>
<CAPTION>

        SIGNATURE                                  TITLE                          DATE
        ---------                                  -----                          ----
<S>                                  <C>                                        <C> 
  /s/ MILTON J. WALLACE              Chairman of the Board                   March 29, 1999
-----------------------------         Of Directors
    Milton J. Wallace                  

/s/ ARTHUR G. SHAPIRO, M.D.           Vice Chairman of the Board             March 29, 1999
-----------------------------         Director of Medical Affairs
 Arthur G. Shapiro, M.D.              

    /s/ JAMES P. SHEA                President/CEO, Director                 March 29, 1999
-----------------------------
      James P. Shea

   /s/ MARK D. WALLACE               Director/Secretary                      March 29, 1999
-----------------------------
     Mark D. Wallace

/s/ EUGENE P. CONESE, SR.            Director                                March 29, 1999
-----------------------------
  Eugene P. Conese, Sr.

 /s/ C. DAVID FINCH, M.D.            Director                                March 29, 1999
-----------------------------
   C. David Finch, M.D.

  /s/ JOHN E. HUNT, SR.              Director                                March 29, 1999
-----------------------------
    John E. Hunt, Sr.

  /s/ JEFFREY H. WATSON              Director                                March 29, 1999
-----------------------------
    Jeffrey H. Watson

  /s/ CHARLES J. SIMONS              Director                                March 29, 1999
-----------------------------
    Charles J. Simons

   /s/ ORESTES L. LUGO               Vice President/Chief                    March 29, 1999
-----------------------------         Financial and Principal
     Orestes L. Lugo                  Accounting Officer
                                      
</TABLE>





                                       48
<PAGE>   3
                                 EXHIBIT INDEX


Exhibit 
Number            Description
-------           -----------

10.11             Employment Agreement dated March 1, 1997 by and between 
                  Renex Corp. and Mignon Early