Is bone graft fundamental in opening wedge high tibial osteotomy? Evaluation of the short-term results of opening wedge high tibial osteotomy without using bone graft

Introduction
High tibial osteotomy has been described as an effective procedure for treatment of medial compartmental osteoarthritis of knee. Many techniques have been developed (closing wedge, opening wedge, etc.), but opening (medial) and closing (lateral) wedge osteotomies are the most commonly used. The use of autograft was the gold standard in opening wedge osteotomy for a long time.
Patients and methods
This is a prospective study carried on 32 knees in 19 patients in a period between January 2011 and January 2013, with a mean follow-up of 17.4±2.87 months. There were 12 males and seven females, with a mean age of 42.5±10.68 years. There were 13 cases with 26 knees with primary osteoarthritis and six were post-traumatic. The preoperative varus angle was measured by the hip–knee–ankle angle on standing scanogram. A single surgical technique was used for knees: medial opening high tibial osteotomy with locked plate fixation but without filling the defect. The preoperative genu varum could not exceed 15°. The following were evaluated: International knee Documentaion committee Scoring (IKDC) functional score and long-leg standing film were performed preoperatively, postoperatively, and at follow-up to evaluate limb alignment and validate the precision of the correction and its stability over time.
Results
Bone union occurred at 4.3 months on average; two knees required revisions (6.25%). The first was because of delayed union and was revised with an autograft at the seventh month, and another case of nonunion with implant failure was revised at the fourth month by total knee replacement. Before the surgery, the average varus was174±2.18° (165°–176°); after the surgery, the hip–knee–ankle angle was183°±1.88° (179°–184°) (=0.0001). This correction was maintained at follow-up. Average Knee Score was improved from 68.0±20 preoperatively to 91.0±19 postoperatively. The Visual Analog Scale score was 76±23 and 38±19 at preoperative and postoperative, respectively, with an average reduction of 38 points. Full weight-bearing without assistance was possible after 3 months on an average.
Conclusion
Union of the arthritic knees was possible without using bone graft (BG). The time to union was comparable to that after using (BG). Meanwhile, It avoids the risks and complications that might be associated with the use BG or Bone substitutes.