What is Semimembranosus Tendinopathy?

Semimembranosus Tendinopathy is the inflammation of the insertion of the semimembranosus tendon. This may be leading to activity-related posteromedial knee pain.

Semimembranosus muscle is one of the hamstring muscles situated at the posteromedial aspect. The most important function of the semimembranosus muscle in flexion and internal rotation of the knee joint. Additionally, it facilitates the extension of the hip joint and stabilizes the pelvis.

The incidence is more common in older patients as well as the athletic population.

Causes and mechanism of Semimembranosus tendinopathy:

  • During repetitive knee flexion, the semimembranosus tendon is subjected to increased friction from the adjacent structures.
  • Repetitive eccentric loading and friction of the tendon can cause degenerative changes.
  • The stress placed on the tendon is due to a sudden increase in intensity, frequency, or duration of training.
  • Common risk factors are:
    • distance running,
    • triathlon,
    • race walking,
    • weightlifting,
    • climbing,
    • running down hills,
    • poor strength and flexibility,
    • failure to warm up properly before activity,
    • Incorrect knee alignment (knock knees or bowlegged) and flat feet.
  • Other knee pathologies such as;
    • Chondromalacia patallae,
    • Degenerative medial meniscal tears,
    • Osteoarthritis.

Clinical Presentation of patients:

  • An insidious, progressive pain in the posteromedial aspect of the knee,
  • Tenderness on palpation,
  • Pain is usually localized at the posteromedial knee at the direct insertion. Pain may radiate distally to the medial calf or proximally up the posteromedial thigh,
  • Symptoms increase with activities that involve significant hamstring activation- running, cycling, walking downstairs, or sudden deep knee flexion.

Physiotherapy Management:

  • Pain relief by:
    • Icing, isometric exercises, Cryo compression therapy.
  • Therapeutic modalities:
    • Short wave diathermy, Combo therapy (U.S + TENS), Extracorporeal Shock Wave Therapy.
  • Soft tissue mobilization
  • Hamstring strengthening:
    • Isometric exercises- this can help in strengthening the muscle as well as reduce pain. And include such as:
      • Isometric leg curl,
      • Bridge holds – hip in neutral,
      • Isometric straight leg pulldowns,
      • Trunk extensions,
      • Performing isometric long leg bridges on two, progressing to one leg holds.
    • Isotonic exercises- this will help to restore hamstring strength, muscle bulk, and capacity in a functional range of movement. In isotonic exercises, we have eccentric and concentric exercises. For example:
      • Single leg bridge,
      • prone hip extension,
      • prone leg curl,
      • Nordic hamstring exercise,
      • Bridging progressions,
      • Supine leg curler.