Low tibial osteotomy alone proves successful for ankles with specific varus-type OA

Yet, the procedure failed to achieve normal joint space in ankles with greater than 10° of varus tilt.

In a retrospective study of 25 women (26 ankles) that received open wedge osteotomy alone for varus-type osteoarthritis (OA), researchers from Nara Medical University in Japan clinically rated 19 ankles as having good or excellent results.

“Their mean scores for pain, walking and activities of daily living were significantly improved, but there was no change in the range of movement,” the researchers wrote in their study, which was published in the British edition of the Journal of Bone and Joint Surgery.

Yet, the investigators discovered better outcomes based on the ankles' preoperative varus-type. They categorized the ankles into the following stages:

Stage 1: osteophytes and early sclerosis, with maintenance of the joint space;
Stage 2: medial joint space narrowing (3 ankles);
Stage 3a: “obliteration of the joint space at the medial malleolus only” (11 ankles);
Stage 3b: obliteration through the dome of the talus (12 ankles); and
Stage 4: obliteration of the joint space and “complete bone contact.”

During a mean follow-up of 8 years and 3 months, the researchers found that all of the ankles preoperatively rated as stage 2 and 10 stage 3a cases advanced to Stage 1. Yet, only 2 ankles rated 3b progressed to the same level.

“Low tibial osteotomy provides good long-term results in varus osteoarthritis of the ankle limited to stage 2 and stage 3,” the researchers wrote.

An examination of varus tilt also revealed that ankles with 5° or less had good outcomes.

“However, none of the 7 ankles in which the varus tilt angle was more than 10° attained a normal joint space, indicating that stage 3b may be beyond the limit,” the researchers wrote. “Perhaps a combination of osteotomy and reconstruction of the lateral ligament would have provided better results for these ankles, although we consider this to be unlikely.”

For more information:
Tanaka Y, Takakura Y, Hayashi K, et al. Low tibial osteotomy for varus-type osteoarthritis of the ankle. J Bone Joint Surg Br.2006;88-B:909-913.