A knot is a knot imho. Square knots are what I throw because that's what was pounded into me. Certainly square knots are useful for closing abdominal fascia, or other high tension closures, but square knots are not essential in every scenario.
If you think about it, why in the world is a square knot essential for closing skin? Most of the attendings in my program don't even use suture for skin... they use staples. And why should a square knot be essential for closing skin which should be under zero tension anyway? A "granny" knot will work just as well for skin or other zero tension closures. I've even started selectively using dermabond in the ED to close some small, clean, lacs...
Dre, I'm not trying to pick a knot fight here, but the "square knot mafia" mentality never made sense to me. Now, being ambidextrous does make sense, and I encourage all trainees to get equally comfortable with tieing with either hand.
I suppose I'm guilty of that as well. I make a point of throwing square knots because that's what's been drilled into me since I started sewing. As far as skin closure goes, it depends on what situation you're describing. For a small skin closure, by the time you get to the skin, it should be zero-tension. In most cases I favor a running subcuticular stitch over stapling, because the subcuticular stitch allows for closer approximation of wound edges, leading to a smaller scar. The real strength of closure derives from approximation of the superficial fascial system as described by Lockwood et al. However, when you're doing something like an a-plasty on a big person, the case can be long enough to allow for significant primary contraction and no matter how good your subcutaneous/SFS closure is, the dermis on the apposed wound edges always wants to pull away from itself, which can lead to exposed dermis without good subcuticular closure. That is, the size of the incision combined with the size of the patient dictates that there will be some tension on the skin closure.
No knot fight necessary, even though I've been forced to join the Square Knot Mafia. Ambidexterity is also good.
Studies have actually shown that loop (slip) knots have greater tensile strength under tension than do square knots.
Furthermore, it has been shown that anchoring a running stitch by starting with half-hitches and ending with a square knot is safer and more secure.
I read that study. I hadn't seen it before, and it's pretty interesting. However, there are a few problems with it: first, the study is based on only 5 knots with 5 throws each tied, all tied by the same person; second, the knots were tied in a "dry" fashion (i.e. not in a real operative situation); and third, the sutures all had their loops divided and forcibly distracted at 180 degrees (again, not realistic) at half a centimeter per minute with a preload of 1 kN (~100 kgf!). If I saw one of my sutures being stretched 50 mm in one minute, I would become mildly distressed. Finally, the study also concludes that larger suture has a lower tensile strength, which seems slightly counterintuitive.
Basically, the study conditions are not realistic, and the authors themselves acknowledge that they do not assess for knot slippage--only tensile failure of the material--and I've always been taught that a slipknot does just that, it slips. My guess is that the authors obtained the results that they did because their testing apparatus exposed the suture to artificially increased angles, which enhances the point of weakness (i.e. suture kinking) created by any knot, and extremely high tensile forces. A better way to test this question would be to reduce the angles to something closer to a real-life scenario, to have many different knot-tyers tying a much larger number of knots, to assess for knot slippage as a measure of knot failure, and to test more than three kinds of suture.
As for skin closure, many of our plastic and breast surgeons don't tie in the suture at all; they place a subq stitch without tieing either end (to approximate the skin), dermabond over the top and then pull out the suture (or cut it at the edge of the skin and leave it) when the dermabond is dry.
Every surgeon likes to do something different. Some people like to run a subcuticular Monocryl/Prolene/whatever with the ends left free and reinforce it with Dermabond or Steri-Strips, others like to anchor the subcuticular closure with a knot. Depends on who's operating. I personally favor Prolene with the ends left free and Steri-Strips.
gave me a few suggestions but a lot of the books don't do a great job if you've never learned them or don't have someone to show you. 
Not THAT many, promise! 
