Meniscal Pathology & Biomechanics article

[Eric Magrum]

Who doesn’t have a patient to relate some of the discussion in this review.

What specific points in this review were new to you; and how can you use those points to better take care of a specific patient you have/had or future patients?

Rainy Saturday article of the weekend

Attachments:

You must be logged in to view attached files.

[Sarah Bosserman]

1.Partial meniscectomy involving up to 50% of the width of the posterior horn of the medial meniscus does not increase contact pressures in the knee.
2. Vertical tears inc max contact pressures, but pressures can be restored to near normal levels with repair.
3. Horizontal cleavage tears have the least impact on contact pressure, thus resection should be reserved for those more symptomatic and should involve a single leaflet when possible.
4. Repair of a root tear may return contact pressures to near normal levels. Root avulsions can cause meniscal extrusion, loss of circumferential fibers which inhibit creation of hoop stresses (and thus prevent function of the meniscus) = act as a functional meniscectomy.
5. Early compensatory changes in gait to avoid or alleviate pain can cause long term changes: should pay attention to reduced ROM of the joint, subconscious gait adaptations developed early on, and muscular strength deficits in knee (isometric max voluntary contraction and rate of force development).
6. Partial meniscectomy has been shown to lead to inc KAM and inc stress to the ACL, predisposing them to OA.

-I thought this was an interesting review and reminded me of some of the points made during the running medicine conference after ACL-R. Quad strength and ability to recruit the muscle quickly, along with knee flexion angles were impacted for a more significant length of time (and to a greater extent) than I may have originally realized.
-Another good point: “Reductions in knee extensor moments may be an important indirect indicator of the presence of persistent pain and changes in joint loading” – this is seen in those with OA to decrease joint loading and may lead to development of a posterior capsule contracture due to prolonged knee flexion…In future patients, this is important to keep in mind, especially for those patient that have been dealing with pain for a long time before seeking treatment.

[Justin Pretlow]

1. Patients post meniscectomy exhibited decreased knee flexion moments during walking compared to contralateral limb – knee flexion moment increased over time from 3 months to 2 year follow up. This made me think of Heiderscheidt’s videos of ACL-R patients with decreased knee flexion moments years out from surgery and long after being allowed to return to sport. For the patient post meniscectomy, who is progressing well, but still walking with mildly decreased knee flexion on the operative limb – I may spend more time using a mirror or video of their gait to make sure they understand the compensation taking place and try to prevent it from becoming an unconscious habit.
2. Radial tears of the lateral meniscus resulting in no increase in contact pressure until they reached 90% or 100% of the width. These stats may be helpful in educating the patient with knee pain/dysfunction who has already had an MRI showing meniscus tear and has questions about why physical therapy can help or if they need surgery to address the tear.
3. Root avulsions can lead to meniscal extrusion, loss of circum. fibers, and inhibit the creation of hoop stresses, serving as a functional meniscectomy. I found this helpful in visualizing the impact of a root tear/avulsion on the function of the meniscus.
4. Partial meniscectomy involving up to 50% of the width of the posterior horn of the med. meniscus does not increase contact pressure in the knee joint vs. a complete med. meniscectomy can more than double contact pressures. No increase in contact pressure in this type of partial meniscectomy was surprising to me.

[Tyler France]

I would echo the points that Justin and Sarah found helpful above. I think that some of the points from the article, including the point about radial tears of the lateral meniscus not increasing contact pressure, are excellent things to keep in mind when educating these patients about possible surgery. When working with these patients in the future, I will certainly look more closely at gait and attempt to address if they appear to be compensating to ensure that they do not develop abnormal gait mechanics in the long term. I found the section about the increased strain on the ACL following medial meniscectomy particularly interesting. I have had a couple of patients undergo medial meniscectomy that expressed a desire to return to sports. With this knowledge, I will probably be more thorough and look more closely at functional tests (landing, cutting, etc) before giving a patient the okay to return to sports.

[Katie Long]

I agree with the points brought up above. A lot of this information was new to me in regards to which types of tears increased contact pressures and which did not. I thought the point made about root tears being the functional equivalent of a meniscectomy was very interesting. It makes sense in regards to the hoop stresses. It also reminded me of Dr. Gawathmy’s point regarding alterations in labral suction in hip surgeries gone bad. Those contact points for these connective tissues are essential and once that “seal” is lost, it obviously has very significant effects on contact pressures and function of the tissue. I also thought the information on the relationships between meniscal tears and resections in regards to ACL strain was interesting, but makes complete sense. As soon as intra-articular structures are altered, that stress and strain is going to have to go somewhere. I think keeping that in mind in these patients is a good treatment consideration. Maybe addressing an increased emphasis on hamstring strength and control to assist in anterior tibial translation control could be a good adjunct to care for these patients.

I am excited to see this published in the JBJS. I hope some of the MDs that refer to me see it! I tend to see a lot of patients after the surgical decision has been made, but I fully intend on using this article as an education tool if I get the chance!

[Author]

Posts