Actual FAI surgery success rates - nowhere near as good as advertised

Another study on the success of surgery for FAI (not good news for patients)

When people are considering surgery for femoroacetabular impingement, they often hear some extraordinarily positive predictions of success.  I had one client say his surgeon said it was 99% certain that the surgery would solve his hip problems. I’ve had people email me from around the world say their surgeons are 90% certain that the surgery will solve their hip pain. But what is the real FAI surgery success rate?

Is the FAI surgery success rate at 90%?

I’ve posted on this topic before, and if you haven’t read that article, it’d be a good idea to do so now. The short version is thatit's extremely optimistic to think FAI surgery is successful over 90% of the time.

The study we’re looking at today is newer and shows us two very important points about the success of FAI surgery. One major point is the overall long term satisfaction rates for the patients. How good is it?

The second point is a hidden issue that the medical literature doesn't pay much attention to. It has to do with how "success" for surgery is calculated. When you see how success scores are calculated for FAI, it becomes very clear that the surgery is not as good as it's long been advertised.

1) What is the overall satisfaction rate of FAI surgery in this study?

For a surgery that surgeons tell you is 90% likely to solve your hip problems, you would expect some pretty great satisfaction results. However, in this study, the results were nothing like 90%.

After two years, "64% of patients were satisfied with their surgical outcome.”

After two years, "64% of patients were satisfied with their surgical outcome.

That is better than a coin toss, but it’s not that much better. That means one out of every three patients was dissatisfied with the surgery. There could be some plausible explanations for that. Perhaps doctors were not selecting patients properly. Perhaps there were a host of confounding factors involved. Perhaps the patients had expectations that were too high? Perhaps the surgery itself is not based on sound physiological principles (the same as many other orthopedic surgeries in the past)? All of these murky possibilities could factor into low satisfaction rates.

The important question is then: how do you minimize the chance of being dissatisfied? Unfortunately, that doesn’t really get looked at deeply in this study. But that leads us to the second major point.

2) Success for the surgeon is not the same as success/satisfaction for the patient

This is a drastically under appreciated element of the story, and this study is a perfect illustration of the problem.

A 20.5 point increase in the NAHS certainly sounds like a spectacular improvement! But look more closely at how it’s scored, and you’ll see how patient satisfaction and surgical “success” are not well aligned.

The study abstract presents some success scores using the Non-arthritic Hip Score (a hip health questionnaire that takes a patient’s answers and creates a numerical representation of their hip health).

"Mean NAHS at preoperative was 54.9...and 24 months: 75.4. This represents a 20.5-point improvement in NAHS (P < 0.001)...In conclusion, arthroscopic surgery for symptomatic femoroacetabular impingement in the community setting provides safe and successful outcomes.

A 20.5 point increase in the NAHS certainly sounds like a spectacular improvement! But look more closely at how it’s scored, and you’ll see how patient satisfaction and surgical “success” are not well aligned.

There are 20 questions in the NAHS. For each question, there are 5 possible answers. If you answer a question in positive way (the answer you would give with a perfectly functioning, non-painful hip), you score 4 points on that question. If you answer in a negative way (meaning you have tons of pain and disability), you’ll get 0 points.

For example, one question is:

How much pain do you have walking on a flat surface?
4 = none
3 = mild
2 = moderate
1 = severe
0 = extreme

If you’re someone with tons of pain, you’ll answer 0, extreme. If you’re in fantastic shape, you answer 4, none.

You answer all 20 questions in the NAHS, multiply your points by 1.25, and you get your final score out of 100. 100 is the best score.

Now, let’s look at the average of 54.9 points that was in this study for patients before the operation. Take a hypothetical person and say they scored 55 points. That means across 20 questions, they generally answered around a 2 or 3 on every question (Total score 55 divided by 1.25 divided by 20 = 2.2). It would be safe to say they had moderate to mild issues with all the questions on the NAHS. On some they may have scored more extreme and on some maybe better, but for simplicity, they averaged out to 2s and 3s on the questionnaire.

After the surgery, let’s assume this person ends up with the total average score of 75.4. What does that mean for their answers to the questions? It means on average they answered 3 (mild problems) across the board (75.4 divided by 1.25 divided by 20).

Let’s make that even more clear: This average patient improved from problems in the 'mild to moderate' range to problems in the 'mild range'. This is not improvement to the point of having no problems. This is not even drastic improvement. The average answer went from 2.2 to 3. That means on a few questions the patient saw some improvement, but nothing had to drastically improve to create this “successful” outcome!

...This average patient improved from problems in the 'mild to moderate' range to problems in the 'mild range'...A 20 point improvement in the NAHS does not mean the hip problem was solved.

A 20 point improvement in the NAHS does not mean the hip problem was solved. At a score of 75.4, it’s highly likely hip irritation remains in mild form. Does that sound like a success from a patient perspective? That really depends on what the patient wants, but it’s highly likely, especially for the athletic population, that lingering mild hip irritation is not a "successful outcome."

Conclusion

Early studies on FAI were case-studies done by surgeons and reported fantastic results based on short term outcomes and questionable metrics. Some studies, like this one, are still claiming high success rates based on bad metrics and even in the face of questionable patient satisfaction rates. Read between the lines when "objective" measures claim great success for this surgery, and you can see why the satisfaction rates for the surgery are not as rosy as they once seemed.

Shane Dowd and I suffered with severe hip pain and limitations for years. We were both too scared to try surgery (since it can't be undone), so we worked on ways to free up our hips and get rid of our pain. We took everything we learned over that years-long struggle and condensed it into a DIY program to help other hip pain sufferers for less than cost of two physical therapy sessions. If you're looking for a solution to your hip problems that doesn't involve drugs, pills, or surgery (and is money-back guaranteed to help you), check out the FAI Fix.

Learn more about our DIY program to help you train out of hip pain.

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About the Author

Matt Hsu is a trainer and orthopedic massage therapist. He fought a long battle with chronic pain all over his body and won. He blends the principles he learned in his journey, empirical observations with clients, and relevant research to help others get their lives back.

Ryan Ferrell - February 1, 2017

A disappointing flaw in this study is not reporting the real-world meaning of the ~20-point gain from often “moderate” to “mild” answers. The authors used a patient-reported outcomes survey that assessed several functional and pain domains (e.g., sitting, traversing stairs, putting on socks, walking, jogging, etc.). Which domains improved exactly?

The worst flaw, however, is in the validity of the survey methodology for demonstrating sustained outcomes of a permanent surgical intervention. We all know our pain fluctuates week to week, day to day, sometimes hour to hour. Bilateral pain also doesn’t mean it stays bilateral; for me at least one hip may be “on” and the other “off” for weeks at a time. Thus, how useful is the author’s patient reported outcomes survey if it only evaluates the last 48 hours and was administered only three times over two years? How much variability in this score could be expected in patients from one week or month to another? A 20-point swing? More temporal resolution is needed to demonstrate sustained outcomes in the real world and eliminate biases in recall or other factors — and the validity of using this survey at just three time points over two years.

I was curious and took the survey this morning, which is relatively good day, and compared it to a fairly bad spell two weeks ago (but not my worst). My score swings from 75 to 47.5 — nearly 30 points. Today’s score of 75, again one of my better days, would NOT be a satisfactory outcome for me after surgery. My best recovery day ever was after soaking in a hot spring (hrm… that relaxed muscles, not bone structure). That evening I had zero pain and could jog without much discomfort at all. My score would have been 97.5 for about 12 hours.

Matt Hsu - February 3, 2017

Ryan, that’s an excellent point. Thank you for sharing that insight. The high variability from one day to the next is extremely important to consider when looking at questionnaires like this. Thank you for pointing this out!

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