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What: Shares of MAKO Surgical (Nasdaq: MAKO) crashed by as much as 41% today after the company reported preliminary sales figures for its second quarter.

So what: RIO system sales came in at just nine systems, following up its disappointing first quarter, which saw only six systems sold. There were a total of 2,590 MAKOplasty procedures performed during the quarter, which was a 66% increase over last year. The company also sold nine total hip arthroplasty applications.

Now what: MAKO has had a rough year so far, even when acknowledging the back-end-loaded nature of its business with most purchases usually taking place during the latter half of each year. CEO Maurice Ferre expressed optimism in long-term growth, but said the company's near-term focus will be improving execution. For the second consecutive quarter, MAKO has now slashed full-year RIO system sales guidance and now expects to sell only 42 to 48 systems this year.

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