External Rotation Recurvatum Test

External Rotation Recurvatum Test ,for Posterolateral Knee Instability, is a gross evaluation of the amount of external femoral rotation that occurs when the knee is hyperextended with the femur stabilized.

See Also: Knee PCL Injury

How do you perform the External Rotation Recurvatum Test?

• With the patient Lying supine, the Examiner Standing at the side of the patient, with one hand stabilizing the distal femur and the other grasping the great toe/ medial foot.
• The examiner passively extends the knee while maintaining stabilization of the femur on the table.

A modification of the test is described:

While holding the heel, the examiner flexes the knee 40°. The opposite hand grasps the posterolateral aspect of the knee. The examiner passively extends the knee while noting external rotation and hyperextension relative to the opposite extremity.

What is a positive External Rotation Recurvatum Test?

Positive Test if there is marked difference in hyperextension, external femoral rotation, and varus alignment between the two knees.

The positive test indicates:

1. Posterolateral corner trauma,
2. ACL sprain,
3. Posterolateral rotary instability.

Reliability

Note that the test is essentially identifying anterior translation of the tibia on the femur. Positive findings are strongly associated with a combined injury to the ACL and the posterolateral corner.

In a Randomized controlled trial study, the sensitivity and specificity of this test was:

• Sensitivity: 3-33%
• Specificity: 94-99 %

Notes

Posterolateral corner injuries can be difficult to diagnose. The external rotation recurvatum test was one of the first clinical tests described to diagnose these injuries. 

The presence of a positive external rotation recurvatum test finding should alert the clinician to the presence of a probable combined posterolateral knee and anterior cruciate ligament injury.

Tightness and spasm of the biceps femoris and semimembranosus may obscure a positive external rotational recurvatum test in the acute or chronic condition.

The external rotational recurvatum test will be negative when the anteromedial and intermediate bundles of the anterior cruciate ligament are intact owing to their contact with the intercondylar shelf in extension.

It is important for the examiner to recognize that a positive finding may not be indicative of any pathology and instead may simply be representative of one’s normal joint extensibility.

Several other selective special tests have been documented to identify trauma to the posterolateral corner of the knee and/or posterolateral rotary instability (PLRI). These techniques are based on replicating the subluxation and/or reduction of the tibia on the femur. Those tests that reproduce tibial subluxation are:

1. the external rotation dial test,
2. the external rotation recurvatum test,
3. the posterolateral drawer test,
4. The reverse-pivot shift test.

References

• LaPrade RF, Ly TV, Griffith C. The external rotation recurvatum test revisited: reevaluation of the sagittal plane tibiofemoral relationship. Am J Sports Med. 2008 Apr;36(4):709-12. doi: 10.1177/0363546507311096. Epub 2008 Jan 8. PMID: 18182654.
• Hughston JC, Norwood LA Jr. The posterolateral drawer test and external rotational recurvatum test for posterolateral rotatory instability of the knee. Clin Orthop Relat Res. 1980 Mar-Apr;(147):82-7. PMID: 7371321.
• Rubinstei n RA Jr, Shelbourne KO, Mccarroll JR, VanMeter CO, Rettig AC. The accuracy of the clinical examination in the setting of posterior cruciate ligament injuries. Am J Sports Med. l 994;22 (4) :550-557.