It's true. Factors other than our patients influence the care physicians provide. In the case of American orthopedic surgery, as I write for The Atlantic, Factor X is the medical device industry.
Today, most orthopedic surgeons train one or two more years extra (that's after eight years of medical school and residency) to focus on specific surgeries that use specific equipment. This wasn't the case a few decades ago. At the same time this trend took off, the companies developing those procedures and marketing that equipment started cutting checks to grease the orthopedic training machine everywhere from America's top hospitals to small private practices.
Despite new rules (detailed in The Medical-Industrial Complex) the money continues to flow. Here's my 2010 rank list of orthopedic fields as favored by the medical device industry:
1. Spine Surgery
2. Hip and Knee Surgery
3. Shoulder and Elbow Surgery
4. Trauma Surgery
5. Orthopedic Oncology
The list is based on the number of training slots available in a given area versus the industry money accepted by the training programs in that area (not gross total funding). It's approximate, given that the number of slots fluctuate, and it's based on the records of the two industry-fed funds for which I was able to obtain records: OREF and OMeGA.