Hi all,
The blog this week is super useful for clinicians. How often does a patient with Achilles tendon pain either ask or have concern about rupturing their tendon? I see 5-10 or so Achilles each week and I reckon most are in this category. This paper is tiny but packs a punch for that reason. It will help you convince patients that their risk of rupture is small – now that’s valuable!
Background: Everyone knows someone who has ruptured their Achilles tendon. Not a good injury. Takes months to recover and you need to do lots of rehab to restore calf function from almost zero. To add to that many people have suboptimal outcomes. These days in the clinic I don’t see many acute ruptures for management/rehab, but I see many people 6+ months down the track post Achilles rupture management (both surgical and conservative) who have ’failed’. Most are unable to do a single leg calf raise. There is a road back, but it is long and difficult (I always tell them that at the start, they don’t like it!).
So understandably, patients who have Achilles pain (and also by the logic above know someone who has previously ruptured their Achilles!) are often scarred to death of rupture. I routinely ask them and find this to be a common fear. Bit of a double-edged sword asking them, as you run the risk of planting the fear in their mind if they were not previously fearful, but you can get around this with good education.
Some of the rupture stats out there are downright scary. For example, the odds of a rupture (on the contralateral side) among someone who has already had a rupture are 176x greater than a rupture occurring in someone who has never had one (
Aroen et al 2004). Important to say we are talking about rare events – eg 6% of the previously ruptured group experienced another rupture. Regardless, that is not a stat that fills people who have ruptured an Achilles with great confidence (don’t tell them).
But we are getting of topic. The focus of the featured study was the following question: Doc, is this painful Achilles tendon likely to rupture on me?
The authors reasoned that Achilles tendons that are painful and those that rupture share similar pathology features. So therefore it is conceivable that some painful Achilles tendons may go onto to rupture.
This
seminal paper from Kannus gave us some answer to the question of how common rupture is when you have a painful tendon. They showed that only 20% among 891 tendons that spontaneously ruptured were previously painful. They prospectively recruited ruptured tendons that presented for treatment. They also took biopsies from the torn tendon and showed that almost all (about 98%) would have had tendon pathology prior to rupture.
Based on the Kannus study 4 out of 5 tendons that rupture have prior pain. The current paper answers the same questions using different methods.
What they did: Data was extracted from the USA-based PearlDiver Record Database. The dataset includes reported data from hospitals and physicians between 2007 and 2011 and has information on 20,484,172 patients. About 9% of people in the USA under 65 years old are represented. The authors identified (based on diagnostic codes) people with Achilles tendon rupture and Achilles tendinopathy between the ages of 20-69 years. The most interesting outcome was incidence of Achilles rupture among people with prior tendinopathy (ruptures on background of diagnosed painful tendinopathy/number with tendinopathy). The same outcome as the Kannus paper but based on retrospective database data rather than patients presenting prospectively for treatment.
What they found: The usual stuff about ruptures being most common among men between the ages of 40-49 was reported, blah, blah, blah. The incidence of ruptures was low (about 0.1%) whereas the incidence of Achilles tendinopathy was 10x higher (about 1%). Approximately 4.0% of patients with Achilles tendinopathy subsequently sustained a rupture and this was greatest in the 40-59 year olds (see figure below).
Clinical interpretation: This is the only study that I am aware that investigates whether tendinopathy leads to rupture among a large dataset. The authors conclude that this finding ‘underscores the success of the various treatment modalities specific to Achilles tendinopathy’. I I'm not sure about that, I think the main points are:
a) Rupture among people with Achilles tendon pain is rare (possibly less common than the 20% reported by Kannus)
b) Rupture and tendinopathy groups are probably different – the reasons for this are debated but may include conscious or unconscious change in motor output secondary to pain, or genetic differences between the groups.
There are major limitations to this retrospective design. First, we cannot be sure the patients were diagnosed accurately and the diagnostic criteria are unclear and may vary between clinicians. Second, it is conceivable that some people who subsequently ruptured did not report this rupture in the current database. Another big issue is not knowing what predisposing factors there may be, eg steroid, fluoroquinolone injection, metabolic factors, etc, that perhaps may have pushed the tendinopathy patients towards rupture. The only one we know about from this paper is age.
To finish with, here is a patient anecdote about the importance in predisposing factors (in this case steroid injection) in Achilles rupture. When working in a tendinopathy clinic in London many years ago I was involved in the management of a 69 yo male with Achilles tendon pain. Long story short, he was administered peri-tendinous steroid after failing initial conservative care (not by me but I was part of the team so had some responsibility). I remember doing a telephone follow up with him a few weeks later and he reported that he was happy with his outcome – he said he felt something go a couple weeks after the injection and had no pain since, but walking was harder. Mistakes will occur, as long as you cop it and learn!
See you next time
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