Brace effects on the unstable knee in 21 cases. A roentgen stereophotogrammetric comparison of three designs.

Three designs of knee braces were investigated in 21 knees with arthroscopically verified old tears of the anterior cruciate ligament. Anterior-posterior and rotatory instability with and without anterior traction were recorded with roentgen stereophotogrammetric analysis. Two of the designs examined reduced the anterior-posterior instability (ECKO, modified Lenox Hill), but not to normal levels. At 20 degree of flexion, none of the braces decreased the internal rotatory instability, whereas one type (modified Lenox Hill) reduced the external rotatory instability.