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Semimembranosus tendinopathy
Other Resources UpToDate PubMed

Semimembranosus tendinopathy

Contributors: Robert Lachky MD, Eric Ingerowski MD, FAAP
Other Resources UpToDate PubMed

Synopsis

Semimembranosus tendonitis / tendinopathy results from repetitive knee flexion, causing the tendon to rub against surrounding structures, which include the medial femoral condyle, medial tibial plateau, semitendinosus tendon, and joint capsule; this can cause tendon damage and an inflammatory response. Patients usually present with a complaint of posterior knee pain, and then pain localized further to the posteromedial knee. Usually, it is a vague pain with insidious onset (described as an ache); onset will be more acute if there was a sudden, dramatic increase in physical activity.

Semimembranosus tendonitis / tendinopathy can occur anywhere from origin to insertion of the tendon; there is also a bursa in this region that can become inflamed. Semimembranosus bursitis is a distinct entity from semimembranosus tendonitis, but it will be grouped together here since the approach is similar for a primary care / emergency physician.

The semimembranosus muscle originates at the lateral ischial tuberosity, and the muscle runs down the posterior medial thigh. The muscle belly ends and the tendon begins just above the knee joint. The tendon then has main insertion on the posteromedial tibial plateau; it also spreads out into different insertion points (eg, one anteriorly on the tibia, one on the popliteus muscle fascia, and one on the posterior medial aspect of femoral condyle). The functions of the semimembranosus muscle are knee flexion, internal rotation, and hip extension.

Patients typically fall into 2 categories:
  • Relatively young adult, athletic individuals
  • Middle-aged / elderly patients
The condition often affects those who climb or cycle as well as triathletes and marathon runners. It may also be triggered by a sudden increase in activity or in intensity of activity. 

There may be other injuries at the same time, and they may be easier to diagnose. Such injuries may overshadow the semimembranosus tendinopathy; often, they will be part of the pathophysiology: Semimembranosus tendinopathy is frequently an overcompensation injury, as the tendon sees more stress if a patient is overcompensating, eg, because of a medial meniscus tear.

The true incidence of semimembranosus tendinopathy is unknown; it is probably underdiagnosed. Posteromedial knee pain is less common than anterior or lateral knee pain.

Codes

ICD10CM:
M76.899 – Other specified enthesopathies of unspecified lower limb, excluding foot

SNOMEDCT:
202873009 – Semimembranosus tendinitis

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Last Reviewed:06/28/2019
Last Updated:11/17/2020
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Semimembranosus tendinopathy
Copyright © 2021 VisualDx®. All rights reserved.