<PAGE>   1

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

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

                                    FORM 10-Q

[X]     QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
        EXCHANGE ACT OF 1934

        For the quarterly period ended March 31, 1999

                                       or

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

        For the transition period from _________ to _________

                           Commission File No. 0-22958

                          INTERPORE INTERNATIONAL, INC.
             (Exact name of registrant as specified in its charter)

                DELAWARE                                        95-3043318
     (State or other jurisdiction of                         (I.R.S. employer
     incorporation or organization)                       identification number)

181 TECHNOLOGY DRIVE, IRVINE, CALIFORNIA                        92618-2402
(Address of Principal Executive Offices)                        (Zip Code)


       Registrant's telephone number, including area code: (949) 453-3200

                                 Not applicable
       ------------------------------------------------------------------
              (Former name, former address and former fiscal year,
                         if changed since last report)

        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 proceeding 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.       Yes  [X]     No  [ ]

        As of May 7, 1999, there were 14,102,403 shares of the registrant's
common stock issued and outstanding.

<PAGE>   2

                          INTERPORE INTERNATIONAL, INC.

                                      INDEX


<TABLE>
<CAPTION>
PART I.        FINANCIAL INFORMATION                                              Page(s)
                                                                                  -------
<S>            <C>                                                                <C>
Item 1.        Financial Statements

                  Condensed Consolidated Balance Sheets as of
                  March 31, 1999 (unaudited) and December 31, 1998 ..............     3

                  Condensed Consolidated Statements of Income (unaudited)
                  for the three month periods ended March 31, 1999 and
                  March 31, 1998 ................................................     4

                  Condensed Consolidated Statements of Cash Flows (unaudited)
                  for the three month periods ended March 31, 1999 and
                  March 31, 1998 ................................................     5

                  Notes to Condensed Consolidated Financial Statements ..........     6

Item 2.           Management's Discussion and Analysis of Financial
                  Condition and Results of Operations ...........................     9

PART II.       OTHER INFORMATION

Item 6.        Exhibits and Reports on Form 8-K .................................    13
</TABLE>


                                       2
<PAGE>   3

                          INTERPORE INTERNATIONAL, INC.
                      CONDENSED CONSOLIDATED BALANCE SHEETS
                        (in thousands, except share data)

<TABLE>
<CAPTION>
                                                                     MARCH 31,      DECEMBER 31,
                                                                       1999             1998
                                                                     ---------      ------------
                                                                    (unaudited)
<S>                                                                  <C>             <C>     
ASSETS
Current assets:
     Cash and cash equivalents                                       $  8,007        $  7,908
     Accounts receivable, less allowance for doubtful
          accounts of $534 and $506 in 1999 and 1998, 
          respectively                                                  7,278           6,418
   Inventories                                                         12,090          12,115
   Prepaid expenses                                                     1,338           1,205
   Deferred income taxes                                                1,426           1,426
   Other current assets                                                   231             436
                                                                     --------        --------
Total current assets                                                   30,370          29,508

Property, plant and equipment, net                                      1,693           1,467
Deferred income taxes                                                   2,559           2,559
Intangible assets, net                                                    378             338
Other assets                                                              318             330
                                                                     --------        --------
Total assets                                                         $ 35,318        $ 34,202
                                                                     ========        ========

LIABILITIES AND STOCKHOLDERS' EQUITY Current liabilities:
     Current portion of capital lease obligations                    $     15        $     15
     Accounts payable                                                   1,109             609
     Accrued compensation and related expenses                            888           1,010
     Accrued royalties                                                    373             300
     Reserve for products liability claims                                177             232
     Accrued disposition costs                                            209             250
     Accrued merger-related expenses and restructuring charges            618             726
     Other accrued liabilities                                            577             873
                                                                     --------        --------
Total current liabilities                                               3,966           4,015
                                                                     --------        --------
Long-term liabilities:
     Long-term debt                                                     3,152           3,152
     Deferred income taxes                                                 55              55
     Obligations under capital leases, net                                 25              29
                                                                     --------        --------
Total long-term liabilities                                             3,232           3,236
                                                                     --------        --------
Contingencies

Stockholders' equity:
  Series E convertible preferred stock, voting, par
    value $.01 per share: Authorized shares - 594,000;
    issued and outstanding shares - 31,573 at March 31,
    1999 and 32,906 at December 31, 1998; aggregate
    liquidation value of $237 at March 31, 1999 and
    $247 at December 31, 1998                                              --              --
  Preferred stock, par value $.01 per share:  Authorized
    shares - 4,406,000; outstanding shares - none                          --              --
  Common stock, par value $.01 per share: Authorized
    shares - 50,000,000; issued and outstanding shares
    - 14,096,029 at March 31, 1999 and 14,059,690 at
    December 31, 1998                                                     141             140
  Additional paid-in-capital                                           44,048          43,962
  Accumulated deficit                                                 (12,960)        (14,042)
                                                                     --------        --------
                                                                       31,229          30,060
  Less treasury stock, at cost - 605,000 shares at
    March 31, 1999 and December 31, 1998                               (3,109)         (3,109)
                                                                     --------        --------
Total stockholders' equity                                             28,120          26,951
                                                                     --------        --------
Total liabilities and stockholders' equity                           $ 35,318        $ 34,202
                                                                     ========        ========
</TABLE>

SEE ACCOMPANYING NOTES.


                                        3
<PAGE>   4

                          INTERPORE INTERNATIONAL, INC.
                   CONDENSED CONSOLIDATED STATEMENTS OF INCOME
                      (in thousands, except per share data)
                                   (unaudited)

<TABLE>
<CAPTION>
                                                   THREE MONTHS ENDED MARCH 31,
                                                   ----------------------------
                                                       1999            1998
                                                     --------        --------
<S>                                                  <C>             <C>     
Net sales                                            $  8,986        $  7,370
Cost of goods sold                                      2,809           1,836
                                                     --------        --------
Gross profit                                            6,177           5,534
                                                     --------        --------
Operating expenses:
     Research and development                             912             861
     Selling and marketing                              3,264           2,739
     General and administrative                         1,015           1,036
     Merger-related expenses                               --              68
                                                     --------        --------
Total operating expenses                                5,191           4,704
                                                     --------        --------
Income from operations                                    986             830
                                                     --------        --------
Interest income                                            96             240
Interest expense                                          (85)           (133)
Other income                                               85              65
                                                     --------        --------
Total interest and other income, net                       96             172
                                                     --------        --------
Income before taxes                                     1,082           1,002
Income tax provision                                       --              59
                                                     --------        --------
Net income                                           $  1,082        $    943
                                                     ========        ========
Net income per share:
     Basic                                           $    .08        $    .07
     Diluted                                         $    .08        $    .07

Shares used in computing net income per share:
     Basic                                             13,462          13,817
     Diluted                                           14,277          15,239
</TABLE>


SEE ACCOMPANYING NOTES.


                                       4
<PAGE>   5

                          INTERPORE INTERNATIONAL, INC.
                 CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS
                                 (in thousands)
                                   (unaudited)

<TABLE>
<CAPTION>
                                                              THREE MONTHS ENDED MARCH 31,
                                                              ----------------------------
                                                                  1999            1998
                                                                --------        --------
<S>                                                             <C>             <C>     
OPERATING ACTIVITIES
Net income                                                      $  1,082        $    943
Adjustments to reconcile net income to net cash
  provided by (used in) operating activities:
          Depreciation and amortization                              214             165
          Changes in operating assets and liabilities:
               Accounts receivable                                  (860)           (497)
               Inventories                                            25            (736)
               Prepaid expenses                                     (133)           (212)
               Other assets                                          219             668
               Accounts payable                                      500              28
               Accrued liabilities                                  (549)           (784)
                                                                --------        --------
Net cash provided by (used in) operating activities                  498            (425)
                                                                --------        --------
INVESTING ACTIVITIES
Sales of short-term investments, net                                  --           2,856
Capital expenditures                                                (413)           (104)
Expenditures for patent rights                                       (69)             (9)
                                                                --------        --------
Net cash provided by (used in) investing activities                 (482)          2,743
                                                                --------        --------
FINANCING ACTIVITIES
Repayment of long-term debt and capital lease obligations             (4)             (4)
Proceeds from exercise of stock options                               87             249
                                                                --------        --------
Net cash provided by financing activities                             83             245
                                                                --------        --------
Net increase in cash and cash equivalents                             99           2,563
Cash and cash equivalents at beginning of period                   7,908          11,809
                                                                --------        --------
Cash and cash equivalents at end of period                      $  8,007        $ 14,372
                                                                ========        ========
</TABLE>

SEE ACCOMPANYING NOTES.


                                       5
<PAGE>   6

                          INTERPORE INTERNATIONAL, INC.
              NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS
                                   (unaudited)


1.  ORGANIZATION AND DESCRIPTION OF BUSINESS

        Interpore International, Inc., doing business as Interpore Cross
International ("Interpore Cross"), is a medical device company that operates in
one business segment: the design, manufacture and marketing of synthetic bone
and tissue products and spinal implant devices. The products are distributed in
the United States and internationally.

2.  BASIS OF PRESENTATION

        The accompanying unaudited condensed consolidated financial statements
have been prepared without audit, pursuant to Securities and Exchange Commission
regulations. In the opinion of management, the accompanying condensed
consolidated financial statements include all adjustments (consisting only of
normal recurring adjustments) necessary to present fairly the consolidated
financial position at March 31, 1999 and the consolidated results of operations
and cash flows for the three month periods ended March 31, 1999 and 1998.

        The accompanying condensed consolidated financial statements include the
accounts of Interpore Cross and its subsidiaries after elimination of all
significant intercompany transactions.

        The results of operations and cash flows for the three months ended
March 31, 1999 are not necessarily indicative of results to be expected for
future quarters or the full year.

        The merger of Interpore and Cross has been accounted for as a
pooling-of-interests. Accordingly, financial information for all periods
presented has been restated to include the financial information of each
company.

        These consolidated financial statements should be read in conjunction
with the financial statements included in Interpore Cross' Annual Report on Form
10-K for the year ended December 31, 1998, as filed with the Securities and
Exchange Commission.

3.   BUSINESS COMBINATION

        On May 7, 1998, Interpore International ("Interpore") merged with Cross
Medical Products, Inc. ("Cross"), a publicly traded Ohio-based worldwide
supplier of spinal implant systems used to treat degenerative conditions and
deformities of the spine. Shareholders of Cross received 1.275 shares of
Interpore common stock for each share of issued and outstanding Cross common
stock. Accordingly, Interpore issued 6.7 million shares of its common stock to
Cross shareholders in exchange for all of the outstanding common stock of Cross.
In addition, approximately 895,000 shares of Interpore Cross common stock were
reserved for issuance upon the exercise of assumed Cross stock options.


                                       6
<PAGE>   7

4.  INVENTORIES

        Inventories are stated at the lower of average cost or market.
Inventories are comprised of the following (in thousands):

<TABLE>
<CAPTION>
                           March 31,       December 31,
                             1999              1998
                           ---------       ------------
<S>                        <C>               <C>    
     Raw materials         $ 1,063           $ 1,024
     Work-in-process           391               279
     Finished goods         10,636            10,812
                           -------           -------
                           $12,090           $12,115
                           =======           =======
</TABLE>

5.  CONTINGENCIES

        Cross and a number of other spinal implant manufacturers were named as
defendants in various products liability lawsuits alleging injuries from spinal
implants supplied by Cross and others. All such lawsuits were consolidated for
pretrial proceedings in the Federal District Court for the Eastern District of
Pennsylvania and, on February 22, 1995, class certification was denied. This
forced the plaintiffs to file individual, rather than class action suits. Over
1,100 such suits were initially filed; however, Cross was dismissed from these
lawsuits for failure of the plaintiffs to state a viable claim. A large number
of plaintiffs filed new lawsuits against Cross and others alleging, in addition
to damages from spinal implants, a conspiracy among manufacturers, physicians
and other spinal implant industry members to defraud the public and market
products without the proper regulatory approvals. Cross was named as a
defendant, among others, in approximately 797 such lawsuits. Interpore Cross
cannot estimate precisely the number of such lawsuits that may eventually be
filed or in how many lawsuits Cross will be named as a defendant. In
approximately 235 of these cases, which involved products manufactured by
Acromed, another spinal implant manufacturer, Cross has been dismissed as a
defendant. Cross has also been dismissed as a defendant from approximately 79
additional cases. Of the remaining conspiracy cases, none involve products
manufactured by Cross.

        The conspiracy cases remain coordinated for pretrial purposes only.
Plaintiffs in the conspiracy cases typically seek relief in the form of monetary
damages, often in unspecified amounts. While the aggregate monetary damages
eventually sought in all of such individual actions are substantial and exceed
the limits of Cross' products liability insurance policies, Interpore Cross
believes that Cross has affirmative defenses, and that these individual lawsuits
are otherwise without merit.

        The lawsuits are being defended by Cross' insurance carrier, in some
cases under a reservation of rights. Cross maintains claims made products
liability insurance policies with at least $5 million of coverage both per
occurrence and in the aggregate. Interpore Cross and Cross believe that they
have adequate insurance for their businesses, however, there can be no assurance
that the limits of coverage will be sufficient to cover the cost of defending
all lawsuits or the payment of any amounts that may be paid in satisfaction of
any settlements or judgments. Further, there can be no assurance that Cross will
continue to be able to obtain sufficient amounts of products liability insurance
coverage at commercially reasonable premiums. Future operating results could be
materially adversely affected by the cost of defending litigation or the formal
resolution of pending cases or future claims, whether or not such defense costs,
cases or claims are covered by insurance.

        Aside from the conspiracy litigation, the nature of Interpore Cross'
business subjects it to products liability and various other legal proceedings
from time to time. In the opinion of management, the amount of ultimate
liability with respect to any known proceedings or claims, excluding the
conspiracy litigation, will not materially affect the financial position or
results of operations of Interpore Cross.


                                       7
<PAGE>   8

6.  LONG-TERM DEBT

        The 8.5% Convertible Subordinated Debentures (the "Debentures") due June
1, 2003 are convertible at any time before maturity, unless previously redeemed,
into shares of Interpore Cross common stock at a conversion price of $6.37 per
share. Beginning July 1, 1999 and on July 1 of each succeeding year, Interpore
Cross will be obligated to redeem any Debentures tendered by June 1, 1999 or
June 1 of any succeeding year, respectively, at 100% of the principal amount
thereof plus accrued interest, subject to an annual limitation of $25,000 per
holder and an annual aggregate limitation of $262,500. During the first three
months of 1999, no Debentures were converted into shares of Interpore Cross
common stock. The fair value of the Debentures approximates the book value at
March 31, 1999 and December 31, 1998.


                                       8
<PAGE>   9

ITEM 2. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
        OF OPERATIONS

DESCRIPTION OF BUSINESS

        Interpore International, Inc. ("Interpore Cross") designs, manufactures
and markets synthetic bone and tissue products and spinal implant devices. Our
merger with Cross Medical Products, Inc. ("Cross") in May 1998 has significantly
increased our focus on the spine market, one of the fastest growing areas within
the orthopaedic marketplace. We report our sales in two product categories: bone
biologics and spinal products.

        Bone biologics are comprised of Pro Osteon(R) bone graft substitute
products and OEM hydroxyapatite products. These products are derived from coral
and serve as a lattice for new bone growth when implanted into a bone defect.
The unique, interconnected porous architecture of the product is a key to its
success as a bone graft substitute. Bone graft substitutes such as Pro Osteon
offer distinct advantages over autografts and allografts. In an autograft, bone
is taken from another part of the patient's body, and frequently creates pain,
longer recovery, and risk of other complications for the patient. An allograft,
or bone taken from a cadaver, carries the risk of implant rejection or disease
transmission. Bone biologics also includes our recently introduced AGF(TM)
(Autologous Growth Factors(TM)) related products, which can be used with a bone
graft material, such as Pro Osteon, to encourage bone growth. AGF is comprised
of concentrated growth factors derived from platelets in the patient's own blood
during the surgical procedure.

        In the spine products category, we offer the Synergy(TM) Spinal System,
which is used to facilitate spine fusions in patients suffering from
degenerative conditions and deformities of the spine. These conditions
frequently cause severe pain and loss of muscle function in patients. The
Synergy System is comprised of titanium or stainless steel hooks, rods and
screws and the instruments required for the surgeon to assemble a construct
which restores the natural anatomy, keeping it immobilized while a bone graft
eventually fuses the vertebrae naturally.

        Prior to the merger, we distributed our bone biologics products through
employee direct sales representatives and commissioned independent agents in the
U.S., and through stocking distributors outside the U.S. In the U.S. we had been
converting to direct representatives because we believed, with only bone graft
products in our product portfolio, we could get more focused sales time compared
to independent agents carrying other product lines. Cross was distributing its
products in the U.S. solely through independent agents, and internationally
through stocking distributors. In the U.S., both companies' sales forces were
calling directly on the same decision-maker - the orthopaedic/spine surgeon,
providing part of the rationale for the merger. Once the merger was completed,
the respective companies' product portfolios were combined, and as a result we
found we could attract independent agents that desired our complementary product
portfolio and that possessed strong surgeon relationships, an important factor
for competing in this industry. Therefore, we expect to continue to increase our
use of independent agents for the domestic distribution of both bone biologics
and spine products.

        Currently, the surgeon is the key decision maker with respect to the
purchase of our products, and the hospital pays our invoices directly. However,
for many other medical device products, the purchasing decision has been assumed
by hospital purchasing departments, buying groups or managed care organizations.
Also, for some other medical device products, insurance companies and Medicare
have refused to reimburse the hospital, or the company directly in the case of
direct-to-insurer billing by the company, and therefore reimbursement becomes an
issue. These factors have not been an issue for us to-date. However, in the
future there can be no assurance that the decision-making responsibility will
not shift from the surgeon, or that reimbursement will not become an issue
affecting our revenues. Other factors potentially affecting continued revenue
growth include: the pricing practices of our competitors, competitive new
product introductions, and our ability to continue to attract and retain
qualified direct sales representatives, independent agents, and distributors.
Sales to our OEM customers and our international distributors are affected by
their purchasing practices, and in the case of international sales, by the
financial capacity of our distributors and the economic conditions in their
countries. Continued revenue growth may also depend upon our ability to
successfully introduce new products or product improvements. See "Certain
Business Considerations" in our 1998 Annual Report on Form 10-K.


                                       9
<PAGE>   10

SIGNIFICANT EVENTS

        In February 1998, we entered into an agreement to merge with Cross, a
publicly traded Ohio-based worldwide supplier of spinal implant systems used to
treat degenerative conditions and deformities of the spine. The shareholders of
both companies approved the merger on May 6, 1998 and it became effective on May
7, 1998. We exchanged approximately 6.7 million shares of our common stock for
all of the common stock of Cross. We accounted for the merger as a
pooling-of-interests.

RESULTS OF OPERATIONS

        The following table presents our results of operations as percentages:

<TABLE>
<CAPTION>
                                                 Three months ended March 31,         Change
                                                 ----------------------------     -------------
                                                    1999             1998         1999 vs. 1998
                                                    -----            -----        -------------
<S>                                                 <C>              <C>               <C>  
Net sales                                           100.0%           100.0%            21.9%
Cost of goods sold                                   31.3%            24.9%            53.0%
                                                    -----            -----             ----      
    Gross profit                                     68.7%            75.1%            11.6%
                                                    -----            -----             ----      
Operating expenses:
  Research and development                           10.2%            11.7%             5.9%
  Selling and marketing                              36.3%            37.2%            19.2%
  General and administrative                         11.3%            14.0%            (2.0%)
  Merger related expenses                              --               .9%              n/a
                                                    -----            -----             ----      
Total operating expenses                             57.8%            63.8%            10.4%
                                                    -----            -----             ----      
Income from operations                               10.9%            11.3%            18.8%
                                                    =====            =====             ====
</TABLE>

        For the quarter ended March 31, 1999, net sales of $9.0 million were
$1.6 million or 21.9% higher than net sales of $7.4 million for the same period
of 1998.

<TABLE>
<CAPTION>
                                       Three months ended March 31,                Change
                                       ----------------------------       ---------------------
                                           1999            1998           Amount             %
                                          ------          ------          ------           ---- 
<S>                                       <C>             <C>             <C>              <C>  
Spinal implant product sales              $4,843          $3,663          $1,180           32.2%
Bone biologics product sales               4,143           3,707             436           11.8%
                                          ------          ------          ------           ---- 
Total net sales                           $8,986          $7,370          $1,616           21.9%
                                          ======          ======          ======           ==== 
</TABLE>

        Sales of spinal implant products increased in the quarter ended March
31, 1999 by $1.2 million or 32.2% to $4.8 million compared to $3.7 million for
the quarter ended March 31, 1998. The increase reflects continued market
penetration of this relatively new system, aided by the improved distribution
and greater domestic territory coverage following the merger.

        Sales of bone biologics products increased by $436,000 or 11.8% to $4.1
million for the three months ended March 31, 1999 compared to $3.7 million for
the three months ended March 31, 1998. Our new AGF related products, used to
collect and concentrate growth factors from the patient's blood, were sold to
selected pre-launch reference sites and accounted for $319,000 of the increase
in sales of bone biologics products. OEM bone biologics products, which are
dependent upon the ordering patterns of two customers, increased by $203,000 or
188% in the first quarter of 1999 compared to the same quarter of 1998. Pro
Osteon sales decreased by $86,000 or 2% versus the same quarter of 1998. We
believe the lack of growth in Pro Osteon sales was primarily related to the
shift in domestic distribution from direct sales representatives to independent
agents which we believe were focusing a greater portion of their efforts on
spinal products sales.


                                       10
<PAGE>   11

        Total domestic sales of bone biologics and spinal implant products
increased 28.5% or $1.5 million to $6.8 million for the three months ended March
31, 1999 compared to $5.3 million for the same period of 1998. International
sales increased $96,000 or 4.7% to $2.1 million for the first quarter of 1999
from $2.0 million for the first quarter of 1998.

        For the quarter ended March 31, 1999, the gross margin was 68.7% of
sales compared to 75.1% of sales for the quarter ended March 31, 1998. The gross
margin in the first quarter of 1998 was the highest of 1998, largely due to
favorable manufacturing variances at Cross. The remaining quarters of 1998
experienced an average gross margin of 71% of sales. Additionally, spinal
implant products have lower gross margins than our bone biologics products, and
the comparatively higher growth in sales of spinal implant products versus bone
biologics products reduced the weighted average gross margin on total sales.

        Total operating expenses for the quarter ended March 31, 1999 increased
by 10.4% or $487,000 to $5.2 million as compared to $4.7 million for the same
quarter of 1998. As a percentage of sales, total operating expenses decreased
from 63.8% in the first quarter of 1998 to 57.8% in the first quarter of 1999.
Research and development expenses increased by 5.9% or $51,000 due primarily to
the hiring of personnel for spinal implant product development projects. Selling
and marketing expenses increased $525,000 or 19.2% compared to the first quarter
of 1998 primarily due to increased commissions on higher sales. General and
administrative expenses decreased by 2.0% or $21,000, the result of efficiencies
realized following the merger and consolidation of facilities. There were no
merger-related expenses during the first quarter of 1999.

        The $76,000 or 44.2% decrease in net interest and other income relates
to a reduction in interest income partially offset by reduced interest expense.
During 1998, cash and cash equivalents declined due to the payment of
merger-related expenses, restructuring charges and non-recurring charges; the
repurchase of our common stock; and the redemption of convertible debentures.
Average cash and cash equivalents balances were accordingly lower in the first
quarter of 1999 versus the first quarter of 1998, reducing interest income.
Also, the redemption of convertible debentures during 1998 reduced the
associated interest expense in the first quarter of 1999.

        No income tax provision was recorded in the first quarter of 1999 and
limited income tax provision was recorded in the first quarter of 1998 due to
the utilization of net operating loss carryforwards.

LIQUIDITY AND CAPITAL RESOURCES

        At March 31, 1999, cash and cash equivalents totaled $8.0 million as
compared to $7.9 million as of December 31, 1998. Total working capital
increased to $26.4 million from $25.5 million and the current ratio improved to
7.7 at March 31, 1999 from 7.3 at December 31, 1998.

        Our $8.0 million of cash and cash equivalents at March 31, 1999 is
available to support the continued investment in the development of our
business, including the development or acquisition of new bone biologic and
spinal implant products, and possible acquisitions of businesses. We have a $5
million revolving line of credit that had no amount outstanding at March 31,
1999 and which expires in July 1999. We intend to negotiate an extension of the
line of credit prior to its expiration, but there can be no assurance that an
extension will be obtained.

        At March 31, 1999, there were no material commitments for capital
expenditures.

        We believe we currently possess sufficient resources to meet the cash
requirements of our operations for at least the next year.


                                       11
<PAGE>   12

IMPACT OF YEAR 2000

        The Year 2000 issue is the result of computer programs being written
using two digits rather than four to define the applicable year. If not
corrected, many computer applications could fail or create erroneous results by
not recognizing "00" to mean the year 2000. We use only third party software,
and in our Annual Report on Form 10-K for the fiscal year ended December 31,
1997, we reported on our initial assessment of this software.

STATE OF READINESS

        In our initial assessment, we contacted the authors of our critical
software programs and determined that each was either already Year 2000
compliant or expected to be Year 2000 compliant by December 31, 1999. We have
identified our remaining software as well as hardware, vendors and customers
(collectively "Elements") and have determined those which we consider to be
mission critical. For Elements determined to be mission critical, we will seek
to obtain assurances of Year 2000 compliance. The assurances sought will be in
the form of vendor or customer certifications, identification of alternatives,
Company-administered testing efforts, or a combination of certain assurances. We
have no way of ensuring that mission critical vendors or customers will be Year
2000 compliant, and their inability to become compliant on a timely basis could
materially impact our operations or financial condition.

COSTS TO ADDRESS OUR YEAR 2000 ISSUES

        Through March 31, 1999, we have not incurred any material direct costs
associated with Year 2000 issues. Certain costs associated with the
consolidation of operations following our merger with Cross resulted in
obtaining software/hardware that is Year 2000 compliant. While the process of
evaluating Elements is not complete, at this time, we do not believe that we
will need to replace any material non-compliant systems or hire any Year 2000
solution providers. Therefore, at this time, we estimate that future costs to
address Year 2000 issues should not be material.

RISKS OF OUR YEAR 2000 ISSUES

        We have yet to identify any mission critical Element that we expect to
not be Year 2000 compliant. In the continuing process of evaluating Elements, we
will have to rely on third party certifications of Year 2000 compliance. In the
event that mission critical Elements fail to be compliant, we could experience a
material disruption in operations, including, but not limited to: interruption
in supply of parts from vendors, inability to deliver products to customers or
to produce products on schedule, or failure of financial systems, all of which
could materially affect our business and cause a loss of customers.

CONTINGENCY PLANS

        We have not established a contingency plan relative to Year 2000 issues.
As our assessment continues, if it is determined that any mission critical
Elements are likely not to be Year 2000 compliant, we will develop a contingency
plan.

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


        THE QUARTERLY RESULTS CONTAINED HEREIN ARE UNAUDITED AND REFLECT CERTAIN
ASSUMPTIONS OF MANAGEMENT THAT MAY CHANGE. RESULTS OF THE QUARTER MAY NOT BE
REPRESENTATIVE OF RESULTS FOR FUTURE QUARTERS OR INDICATIVE OF OUR FINANCIAL
RESULTS FOR THE YEAR. CERTAIN STATEMENTS IN THIS QUARTERLY REPORT ON FORM 10-Q
ARE FORWARD-LOOKING AND MAY INVOLVE RISKS AND UNCERTAINTIES, INCLUDING, BUT NOT
LIMITED TO: PRODUCT DEMAND AND MARKET ACCEPTANCE RISKS; RISKS RELATED TO THE
DEVELOPMENT OF FUTURE PRODUCTS; RISK THAT WE WILL NOT RECEIVE ADDITIONAL
REGULATORY APPROVAL OF PRODUCTS; AND THE IMPACT OF COMPETITIVE PRODUCTS.
ADDITIONAL INFORMATION ON FACTORS THAT COULD AFFECT OUR FINANCIAL RESULTS AND
GROWTH PROSPECTS IS DISCLOSED IN REPORTS WE FILE FROM TIME TO TIME WITH THE
SECURITIES AND EXCHANGE COMMISSION, INCLUDING IN THE "CERTAIN BUSINESS
CONSIDERATIONS SECTION" OF OUR ANNUAL REPORT ON FORM 10-K.


                                       12
<PAGE>   13

PART II -      OTHER INFORMATION

ITEM 6.        EXHIBITS AND REPORTS ON FORM 8-K

        a.     Exhibits.

               Reference is made to the Exhibit Index on Page 15 hereof.

        b.     Reports on Form 8-K.

               No reports on Form 8-K were filed during the fiscal quarter ended
               March 31, 1999.


                                       13
<PAGE>   14

                                   SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the
Registrant has duly caused this report to be signed on its behalf by the
undersigned, thereunto duly authorized.

DATE:    May 10, 1999             INTERPORE INTERNATIONAL, INC.
                                  (Registrant)


                                  By:   /s/ David C. Mercer
                                        ------------------------------------
                                        David C. Mercer,
                                        Chairman and Chief Executive Officer



                                  By:   /s/ Richard L. Harrison
                                        ------------------------------------
                                         Richard L. Harrison
                                         Sr. Vice President and
                                         Chief Financial Officer


                                       14
<PAGE>   15

                                  EXHIBIT INDEX

<TABLE>
<CAPTION>

 Exhibit
 Number                            Description
 ------                            -----------
<C>     <S>
3.01    Certificate of Incorporation of Interpore International, Inc. as 
        amended (1)
        
3.02    Bylaws of Registrant (1)

3.03    Amendment Number One to Bylaws (17)

4.01    Rights Agreement dated November 19, 1998, between Interpore
        International, Inc. and U.S. Stock Transfer Corporation, which includes
        the form of Certificate of Determination of the Series A Junior
        Participating Preferred Stock of Interpore International, Inc. as
        Exhibit A, the form of Right Certificate as Exhibit B and the Summary of
        Rights to Purchase Preferred Shares as Exhibit C. (2)

10.01   Revised License Agreement dated March 12, 1984, between Registrant and
        Research Corporation Technologies, Inc., as amended by a First Amendment
        dated December 7, 1984, and as further amended by a Fourth Amendment
        dated July 22, 1988 (3)

10.02   Cancellation and Release Agreement dated March 1, 1993 among Registrant,
        Interpore Orthopaedics, Inc., Pfizer, Inc. and Howmedica, Inc. (3)

10.03   Series E Preferred Stock and Common Stock Warrant Purchase Agreement
        dated December 19, 1991 (3)

10.04   Series E Preferred Stock Purchase Agreement dated October 30, 1992 (3)

10.05   Single Tenant Lease dated July 25, 1991 between Registrant and The
        Irvine Company as amended by a Third Amendment to Lease dated December
        11, 1996 (4)

10.06   Amended Schedule to Loan and Security Agreement dated August 11, 1998
        among Registrant, Interpore Orthopaedics, Inc., Cross Medical Products,
        Inc. and Silicon Valley Bank (5)

10.07   Amendment to the Loan Agreement dated August 11, 1998 among Registrant,
        Interpore Orthopaedics, Inc., Cross Medical Products, Inc. and Silicon
        Valley Bank (5)

10.08   Amended and Restated Stock Option Plan dated March 19, 1991 (6), First
        Amendment to the Amended and Restated Stock Option Plan, effective
        October 15, 1991 (3); Amendment to the Amended and Restated Stock Option
        Plan dated September 17, 1994 (7)

10.09   1995 Stock Option Plan (8)

10.10   Stock Option Plan for Non-Employee Directors of Interpore 
        International (9)

10.11   Danninger Medical Technology, Inc. Amended and Restated 1984
        Non-Statutory Stock Option Plan (10)

10.12   Danninger Medical Technology, Inc. Amended and Restated 1984 Incentive
        Stock Option Plan (10)

10.13   Cross Medical Products Inc. Amended and Restated 1994 Stock Option 
        Plan (10)

10.14   Asset Purchase Agreement dated March 12, 1997, among Cross Medical
        Products, Inc., Danninger Healthcare, Inc. and OrthoLogic Corp. (11)

10.15   Indenture concerning 8.5% Convertible Subordinated Debentures between
        Cross Medical Products, Inc. and Fifth Third Bank (12)

10.16   Supplemental Indenture between Interpore International, Inc. and Cross
        Medical Products, Inc. and Fifth Third Bank (5)

10.17   Form of Indemnification Agreement (13)

10.18   Schedule of Parties to Form of Indemnification Agreement (14)
</TABLE>


                                       15
<PAGE>   16

<TABLE>
<CAPTION>

 Exhibit
 Number                            Description
 ------                            -----------
<C>     <S>
10.19   Non-Competition Agreement dated September 6, 1996 between Cross Medical
        Products, Inc. and Stephen R. Draper (15)

10.20   Agreement between Dr. Edward Funk and Cross Medical Products, Inc. dated
        February 11, 1998 (16)

10.21   Form of Employment Agreement dated August 17, 1998 between Interpore
        International, Inc. and its executive officers (14)

10.22   Schedule of Parties to Form of Employment Agreement dated August 17,
        1998 (14)

10.23   1999 Consultants Stock Option Plan (18)

10.24   Amended and Restated Employee Qualified Stock Purchase Plan dated 
        November 13, 1998

11.01   Computations of Net Income per Share

27.01   Financial Data Schedule
</TABLE>

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

(1)     Incorporated by reference from our Registration Statement on Form S-4,
        Registration No. 333-49487.

(2)     Incorporated by reference from our Current Report on Form 8-K dated
        December 1, 1998.

(3)     Incorporated by reference from our Registration Statement on Form S-1,
        Registration No. 33-69872.

(4)     Incorporated by reference from our Current Report on Form 8-K dated
        February 11, 1998.

(5)     Incorporated by reference from our Quarterly Report on Form 10-Q for the
        fiscal quarter ended June 30, 1998.

(6)     Incorporated by reference from our Registration Statement on Form S-8,
        Registration No. 33-77426.

(7)     Incorporated by reference from our Registration Statement on Form S-8,
        Registration No. 33-86290.

(8)     Incorporated by reference from our Proxy Statement for the 1994 Annual
        Meeting of Shareholders.

(9)     Incorporated by reference from our Proxy Statement for the 1995 Annual
        Meeting of Shareholders.

(10)    Incorporated by reference from our Registration Statement on Form S-8,
        Registration No. 333-53775.

(11)    Incorporated by reference from the Cross Medical Products, Inc. Annual
        Report on Form 10-K for the year ended December 31, 1996.

(12)    Incorporated by reference from the Cross Medical Products, Inc.
        Registration Statement on Form S-2, Registration No. 333-02273.

(13)    Incorporated by reference from our Quarterly Report on Form 10-Q for the
        fiscal quarter ended March 31, 1998.

(14)    Incorporated by reference from our Quarterly Report on Form 10-Q for the
        fiscal quarter ended September 30, 1998.

(15)    Incorporated by reference from the Cross Medical Products, Inc.
        Quarterly Report on Form 10-Q for the fiscal year ended September 30,
        1996.

(16)    Incorporated by reference from the Cross Medical Products, Inc. Annual
        Report on Form 10-K for the year ended December 31, 1997.

(17)    Incorporated by reference from our Annual Report on Form 10-K for the
        year ended December 31, 1998.

(18)    Incorporated by reference from our Proxy Statement for the 1999 Annual
        Meeting of Stockholders.


                                       16