Functional Outcome of Modified Downsloping Tibial Tuberosity Osteotomy in Biplanar Opening-wedge High Tibial Osteotomy: A Case Report

INTRODUCTION: Opening-wedge high tibial osteotomy (OWHTO) is a widely used procedure to improve knee function, decrease knee pain and delay arthroplasty in unicompartmental knee osteoarthritis in young patients. However, faulty technique can lead to patella baja and maltracking of extensor mechanism- leading to poor outcome. Modified biplanar downsloping OWHTO - where tibial tuberosity (TT) remains attached to proximal osteotomy fragment prevents patella baja by preventing TT to slide down during opening of osteotomy. Biplanar osteotomy also prevents rotation of distal tibial fragment. Biplanar along with downsloping osteotomy both factors combined prevents patella baja and change in quadriceps vector angle and hence patellar tracking is not altered leading to a better functional result. CASE REPORT: A 20 years male patient with right knee pain while walking for 2 years. Knee inspection shows varus deformity and varus thurst gait. No evidence of ligamentous laxity and meniscal injury. He was treated with modified biplanar downsloping OWHTO. Overall 12 patients were operated between 2018 and 2020 with same technique in a similar profile of patients. CONCLUSION: Outcome of OWHTO can be improved and untoward complications such as patella baja which invariably occurs when TT remains attached to distal osteotomy fragment or when osteotomy passes above TT. This can be easily avoided with this downsloping OWHTO technique to give a better outcome in all 12 cases.