Unhappy triad

Unhappy Triad in Magnetic Resonance Imaging. From left to right: rupture of the anterior cruciate ligament, rupture of the medial collateral ligament, inner meniscus tear (here complex tear of the posterior horn). Most of the time there is still a contusion in the back outside of the shin (far right).

The English term unhappy triad ( dt. , Unhappy triad ") describes the combination of a tear of the anterior cruciate ligament ( lat. Cruciate ligament anterior ) of the medial meniscus ( medial meniscus ) and the medial collateral ligament (inner belt) ( ligamentum collaterale tibiale ). The injury pattern was described by O'Donoghue in 1950 and referred to as the Unhappy Triad by him in 1964 .

So-called "flexion-valgus-external rotation injuries" have often been assumed as causes. This means that the knee is slightly bent, turned into the knock- kneed position and turned outward with the lower leg standing. Skiing accidents in which the patient gets stuck on a ski and thereby triggers the described mechanism are among the “classics” among the injuries.

In recent years, however, doubts about the combination described have been raised several times. In several patient series, the outer meniscus was affected significantly more often than the inner meniscus in the above-mentioned accident mechanism. The Unhappy Triad is therefore probably a less common injury pattern.

Individual evidence

1. ↑ DH O'Donoghue: Surgical treatment of fresh injuries to the major ligaments of the knee. In: J Bone Joint Surg Am 32A, 1950, pp. 721-738. PMID 14784482
2. ^ DH O'Donoghue: The unhappy triad: ethiolgy, diagnosis and treatment. In: Am J Orthop 6, 1964, pp. 242-247. PMID 14237439
3. ↑ E. Luciani: An in vitro study of the tensile forces in the anterior cruciate ligament and anterior cruciate ligament replacement (ligamentum patellae and semitendinosus plastic). Dissertation. LMU Munich, 2003
4. ^ KD Shelbourne and PA Nitz: The O'Donoghue triad revisited In: J Sports Med 19, 1991, pp. 474-477. PMID 1962712
5. ↑ T. Fridén et al .: Compression or distraction of the anterior cruciate injured knee. Variations in injury pattern in contact sports and downhill skiing. In: Knee Surgery, Sports Traumatology, Arthroscopy 3, 1995, pp. 144-147. PMID 8821269

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