Trokos

Test library › Knee

Valgus stress test — 30° flexion

For: MCL sprain

An injury to the medial collateral ligament on the inside of the knee, usually from a force pushing the knee inwards.

A weak test on its own
Sensitivity78%
Specificity67%
LR+ (positive)2.3
LR− (negative)0.33

These figures have not been confirmed against the full paper (checked against the abstract or a secondary source only).

What the numbers mean

  • Positive result: a small shift: a positive result nudges the diagnosis up, but does not settle it.
  • Negative result: a small shift: a negative result nudges the diagnosis down, but does not exclude it.

Work out what a result means for your patient: probability calculator

Source

Kastelein M, Wagemakers HP, Luijsterburg PA, Verhaar JA, Koes BW, Bierma-Zeinstra SM. Assessing medial collateral ligament knee lesions in general practice. Am J Med. 2008;121(11):982–988. PubMed · single study

Figures as they will appear in Rule It In, Rule It Out (Trokos, forthcoming). If a newer or better study changes them, this page changes with the book. Figures last updated from the book on 6 October 2026.

Get the book for how to do and read each knee test with published figures, and which ones to trust for the ACL, meniscus and kneecap

This page gives the published figures. Rule It In, Rule It Out adds how to do this test, what counts as positive, how to read the result, and, where studied, whether combining it with other tests helps.

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One study, one test, once a month

Rule It In is a free evidence letter for musculoskeletal clinicians: one recent study explained, one examination test with its real numbers. From Trokos, publisher of Rule It In, Rule It Out.