What makes knee arthritis more likely after meniscectomy? What doesn’t?

PainSci » bibliography » Salata et al 2010
updated Aug 3, 2016

Tags: knee, surgery, arthritis, counter-intuitive, leg, limbs, pain problems, medicine, treatment, aging

Two pages on PainSci cite Salata 2010: 1. The Causes of Runner's Knee Are Rarely Obvious 2. Your Back Is Not Out of Alignment

PainSci commentary on Salata 2010: ?This page is one of thousands in the PainScience.com bibliography. It is not a general article: it is focused on a single scientific paper, and it may provide only just enough context for the summary to make sense. Links to other papers and more general information are provided wherever possible.

Meniscectomy is a common surgery (and a fairly useless one, see Thorlund). And almost everyone believes that loss of meniscal tissue — a loss of “padding” — leads to knee osteoarthritis. These researchers looked for evidence of it in research done up to 2010.

The data is a bit of a mess and they found a lot of lower level evidence of not much use (“garbage in”). However, they did detect some interesting patterns, a few factors that were clearly associated with either more or less osteoarthritis five or more years after surgery. For instance, they identified several factors that were not associated with more arthritis: gender, age, activity level, and poor mechanical alignment of the knee. Most of those are a bit surprising (all but gender). Surely poor alignment would spell trouble? That’s a common assumption! But apparently it doesn’t.

And since when does age not correlate with arthritis? And wouldn’t the association be even stronger after having some meniscal tissue trimmed away? How odd!

So what did make arthritis more likely? Fairly obvious things: weight, getting more meniscus removed, and crappy genes (inferred from osteoarthritis in other joints). The researchers pointed out that there are likely quite a few other variables that just aren’t represented in this data at all, like smoking and other injuries. “More research needed,” of course.

~ Paul Ingraham

original abstract †Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.

Knee meniscectomy is the most common procedure performed by orthopaedic surgeons. While it is generally believed that loss of meniscal tissue leads to osteoarthritis and poor knee function, many variables may significantly influence this outcome.

Through literature search engines including PubMed and Ovid, 4 randomized controlled trials, 2 prospective cohorts, and 23 retrospective cohorts that fit the criteria for level I, II, and III level of evidence were included in this systematic review. For the level III evidence studies, follow-up of 5 years or more was required. Preoperative and intraoperative predictors of poor clinical or radiographic outcomes included total meniscectomy or removal of the peripheral meniscal rim, lateral meniscectomy, degenerative meniscal tears, presence of chondral damage, presence of hand osteoarthritis suggestive of genetic predisposition, and increased body mass index.

Variables that were not predictive of outcome or were inconclusive or had mixed results included meniscal tear pattern, age, mechanical alignment, sex of patient, activity level, and meniscal tears associated with anterior cruciate ligament (ACL) reconstruction. While an intact meniscus or meniscal repair was generally favorable in the ACL-reconstructed knees, meniscal repair of degenerative meniscal tissue was not favorable.

There is a lack of uniformity in the literature on this subject with a preponderance of lower level evidence. Although randomized controlled trials are considered to be the gold standard in medical research, a multicenter prospective cohort design may be more appropriate in assessing the long-term outcome of meniscal surgery and the role that multiple preoperative and intraoperative variables may play in clinical outcomes. In addition, future studies should include factors not assessed or adequately evaluated by several of the included studies, such as meniscal tear pattern, age, mechanical alignment, sex of the patient, activity level, meniscal tears associated with other injuries such as the ACL, smoking, and the effect of previous surgery.

original abstract †Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.

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