Stay with the Apollos. Have had them since they came out - added steel straps later. Dove with Mares Avanti Quatros before that. I also have a pair of Force fins - like English ale, an acquired taste. (My wife bought them for $20 at an estate sale- virtually unused). Have used a variety of ins over the years going back to raw rubber fitted US divers. Simlpy put, the Aploolos are the best. If you can't find a deal on ebay, craigslist or whatever, you would still be better off even if you had to pay stone cold retail. Cannot address the orthopedic issue; however, prior to the Apollos I had occasional leg cramps (calf). Zero cramps since then. That tells me that here is much less strain. All that with far superior performance (speed, efficiency, reduced air consumption).