Conundrum of Mechanical Knee Symptoms: Signifying Feature of a Meniscal Tear?

Thorlund JB, Pihl K, Nissen N, Jorgensen U, Fristed JV, Lohmander LS, & Englund M. Br J Sports Med. 2018; E-pub ahead of print August 31, 2018. DOI:10.1136/bjsports-2018-099431

Take Home Message: The number of adults with self-reported mechanical symptoms are comparable between patients with and without a meniscus tear. Self reported mechanical symptoms should not be a deciding factor for suspecting a person has a meniscal tear.

A patient often undergoes a knee arthroscopy to alleviate pain and other symptoms, including mechanical limitations associated with meniscal pathology. Surgery is often recommended when there are mechanical symptoms allegedly caused by the meniscal tear, yet newer evidence suggests that outcomes after a partial meniscectomy did not differ from a placebo surgery. Therefore, these researchers conducted this study to see if the presence of a meniscal tear during surgery was associated with self-reported mechanical symptoms before surgery. The authors used self-reported data and surgical reports from 817 adults from the Knee Arthroscopy Cohort Southern Denmark who had meniscal surgery for a suspected meniscal pathology. Within this cohort, 641 adults had a surgically confirmed meniscal tear. The authors defined self-reported mechanical symptoms using a question from the Knee Osteoarthritis Outcome Score (KOOS): “Thinking of your knee symptoms during the last week – Does your knee catch or lock when moving?” Participants were also asked if they can straighten their knee fully. Interestingly, 75% of those who reported mechanical symptoms actually had a meniscal tear, however, 82% of those without mechanical symptoms had a meniscal tear. There were no differences in the reporting rates of mechanical symptoms between those with and without a meniscal tear.

Reported Symptoms No Reported Symptoms
Catching or Locking
Meniscal Tear
No Meniscal Tear
Extension Deficit
Meniscal Tear
No Meniscal Tear

This study is very interesting because it appears that clinicians should be cautious in thinking that a meniscal tear is actually causing patient-reported mechanical symptoms. There are other pathologies that could cause these symptoms, and this needs to be further investigated. It would be interesting to see if patient strength, range of motion, or other clinical findings were associated with any of the patient-reported mechanical symptoms. For instance, a clinically detected mechanical pop during a McMurray’s test may be much different than a patient reporting that their knee catches. Some of the reported mechanical symptoms may be linked to strength deficits, degenerative changes, or other variables, and we should look in to this more. It would be interesting if there was a further look into a sex disparity in self-reported and surgical findings. It appeared that there was twice as many females versus males who did not have a meniscal tear – but I wonder what they reported in regards to their self-reported mechanical symptoms. Ultimately, mechanical symptoms may not relate to a meniscal tear, so as clinicians, we need a more thorough and convincing evaluation to better figure out how to treat our patients.

Questions for Discussion: What do you do as a clinician to help patients decide to have surgery or not? Are there any series of clinical findings that you rely on more than self-reported mechanical symptoms for meniscal tear?

Written by: Nicole Cattano

Reviewed by: Jeffrey Driban

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