Center of Rotation - Ranawat method: How to perform

Last updated on July 6 2022

Description

In the unilateral hip diseases, the center of rotation can be easily determined by mirroring the opposite unaffected hip joint. However, when both hip joints have pathological deviations of the rotational center, other methods may apply. The Ranawat method is one of these methods and it estimates the acetabular position and indirectly constructs the center of rotation from an isosceles right triangle located 5 mm laterally from the intersection of Koehler’s and Shenton’s line. 

This procedure is useful to help find the center of rotation of the injured acetabulum through the location of the center of rotation of the contralateral hip. 

Measurements

There aren’t measurements for this procedure.

Auxiliary References

To show this procedure, PeekMed® needs additional references:

• Iliac Crests’ Line (ICL): line passing through the most proximal edges of the iliac crests;

• Ischial Tuberosities’ Line (ITL): line passing through the most distal edges of the two ischial tuberosities;

• Shenton’s curve: a curved line connecting the medial edge of the femoral proximal metaphysis and the proximal edge of the obturator foramen;

• Köhler's Line: line connecting the most lateral edge of the pelvic brim and the most lateral edge of the obturator;

• Pelvic Height Line: a perpendicular line connecting both ICL and ITL and passing 5 mm medial to the obturators;

• Point A: point resulting from the intersection of the Pelvic Height Line passing 5mm to the obturator;

• Point B: point above Point A exactly ⅕ of the Pelvic Height Line;

• Point C: point lateral to Point B at the same distance as Point B from the Point A;
• Isosceles Triangle: triangle formed connecting Point A, B and C.