Angle Stable Plate Fixation vs Hemicallotasis in Medial Opening Wedge High Tibial Osteotomy: A Comparative Study

Varus alignment associated with medial compartment degeneration is the most common presentation of knee osteoarthritis and often presents in young active adults where arthroplasty might be unsuitable.

To compare the accuracy of the angle stable medial high tibia plate and self-adjusting HTO (high tibial osteotomy) fixator in achieving correction of varus deformity of the knee by medial opening wedge HTO and to evaluate functionality between the groups.

Prospective randomized control study.

Forty patients each underwent medial opening wedge high tibial osteotomy with acute correction and stabilization using the angle stable plate (ASP group) or with the hemicallotasis technique using the self-adjusting HTO external fixator (HCO group). Anatomical and functional outcomes were compared to the pre-operative values at the 6th and 12th month.

The FTA (femoro-tibial axis), mechanical axis, and functional scores improved significantly in both groups. There was also a significant change in the patellar height and tibial slope. Except for a better KOOS (Knee Injury and Osteoarthritis Outcome Score) in the angle stable plate group at the 6-month follow-up, there were no significant differences between the groups.

Both methods of performing a medially based proximal tibial osteotomy gave equivalent outcomes at the 1-year follow-up.