Autograft reconstructions for bone defects in primary total knee replacement in severe varus knees

Abstract

Background:Large posteromedial defects encountered in severe varus knees during primary total knee arthroplasty can be treated by cementoplasty, structural bone grafts or metallic wedges. The option is selected depending upon the size of the defect. We studied the outcome of autograft (structural and impaction bone grafting) reconstruction of medial tibial bone defects encountered during primary total knee replacement in severe varus knees.Materials and Methods:Out of 675 primary varus knees operated, bone defects in proximal tibia were encountered in 54 knees. Posteromedial defects involving 25-40% of the tibial condyle cut surface and measuring more than 5 mm in depth were grafted using a structural graft obtained from cut distal femur or proximal tibia in 48 knees. For larger, peripheral uncontained vertical defects in six cases, measuring >25 mm in depth and involving >40% cut surface of proximal tibial condyle, impaction bone grafting with a mesh support was used.Results:Bone grafts incorporated in 54 knees in 6 months. There was no graft collapse or stress fractures, loosening or nonunion. The average followup period was 7.8 years (range 5-10 years). We observed an average postoperative increase in the Knee Society Score from 40 to 90 points. There was improvement in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores in terms of pain, stiffness and physical function during activities of daily living.Conclusion:Bone grafting for defects in primary total knee is justified as it is biological, available then and is cost effective besides preserving bone stock for future revisions. Structural grafts should be used in defects >5 mm deep and involving 25-40% of the cut proximal tibial condyle surface. For larger peripheral vertical defects, impaction bone grafting contained in a mesh should be done.

Use of autogenous onlay bone graft for uncontained tibial bone defects in primary total knee arthroplasty

“…One study evaluating prerequisites for complete graft incorporation in 24 primary or revision knees reported that pertinent coverage of the graft by the component can prevent resorption of unstressed graft which may contribute to failure by collapse [ 1 ]. However, our study included one case of undersized tibial component on the cortical wall of the proximal tibia related to an our unintentional error during the initial learning curve.…”

“…A severe tibial bone defect in primary total knee arthroplasty (TKA) is one of the biggest challenges to treat for the surgeon, which can lead to a poorly balanced tibial component. Moreover, an uncontained defect is associated with a resultant angular deformity that is usually posterior and medial in a more than 20° varus knee from primary TKA [ 1 ]. The management of bone defects on the tibial aspect can vary depending on the size and location of the loss of bone, and it is necessary to consider other patient specific factors such as age, functional requirements, and bone quality.…”

Using Tibia Proximal Cut Autograft in Advanced Varus Knee Deformity in Total Knee Arthroplasty; Outcomes Compared to the Control Group

“…It is not preferable that the proximal tibia cut level is lower than accepted measures. [ 1 , 6 , 12 ] That is because the tibial base plate cannot be supported by softer cancellous bone and the tendons and ligaments adhering to the proximal tibia may be damaged [ 1 , 6 ]. For this reason, most of the defects of tibial medial plateau have to be reconstructed.…”

“…In advanced varus deformed knees, the defect in the proximal medial tibia usually requires additional surgical procedures. [ 1 - 3 ] Methods used by surgeons for the reconstruction of this defect consist of providing support through cement, metal wedges, the use of autograft, etc . [ 1 , 4 - 8 ] Although TKA has been known to be a satisfying surgery with a success rate above %90, in the case of advanced varus knee deformity, the outcomes of TKA is not clear.…”

“…[ 1 - 3 ] Methods used by surgeons for the reconstruction of this defect consist of providing support through cement, metal wedges, the use of autograft, etc . [ 1 , 4 - 8 ] Although TKA has been known to be a satisfying surgery with a success rate above %90, in the case of advanced varus knee deformity, the outcomes of TKA is not clear. [ 9 - 11 ] We reconstructed the proximal medial defect by using proximal tibial cut bone to provide a firm support for the tibial base-plate.…”