I try not to pay much attention to the quarter-by-quarter gyrations in analyst estimates and opinions, but sometimes you just can't escape it all. Take today, for instance. Zimmer (NYSE:ZMH) is trading lower not because of what might happen over the next three to five years but because of what might happen over the next three quarters.

That said, it wasn't as though this quarter was especially strong. Revenue was up 4% as reported (and 7% in constant currency terms), with pricing essentially stable for the company. Margins did improve, though, and that led to a low-teens boost in operating income. Above and beyond that, there was some juice in the cash flow numbers -- though not so much on a structural free cash flow basis.

In comparison with orthopedic companies that reported earlier, Zimmer was generally weaker. It matched Stryker (NYSE:SYK) with not much going on in the hip category, but it trailed that competitor in the knee and spine categories. It came up short on both the hip and knee categories, along with Biomet (NASDAQ:BMET). And while the dental business was pretty strong, it doesn't really account for much in terms of sales -- likewise for spine products.

Before Zimmer announced earnings Wednesday night, news had come earlier in the week that the company had reached a five-year agreement with HCA (NYSE:HCA), a large hospital operator. HCA and Zimmer have squabbled in the past, but I'd imagine this deal still gives HCA discounts on reconstruction products -- though perhaps not as much as HCA might have wanted.

Looking beyond the immediate line of sight of most analysts, I'm wondering what to make of Zimmer's long-term prospects. Although the stock looks intriguing, I've always held it in a little less esteem than Stryker's stock. On the other hand, Zimmer is trying some interesting things here and there -- like a new knee implant designed especially for women -- and it's an exceptionally profitable firm focused on cash generation.

So I'd still insist on a bit of a discount relative to Stryker shares, but I'm still a believer in an eventual recovery of investor confidence for this sector. Not knowing when that'll happen, though, I'm inclined to stick to my guns here and only buy when there is a fitting margin of safety.

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Fool contributor Stephen Simpson has no financial interest in any stocks mentioned (that means he's neither long nor short the shares).