Abstract
Varus deformity encompasses a wide spectrum of pathology and merits individualised treatment. In most knees there is loss of articular cartilage or bone medially; this is associated with contractures of posteromedial structures of varying rigidity. In addition, there may be significant elongation of lateral ligamentous structures, and associated extra-articular femoral or tibial bowing or angulation. The principles of correction of varus include (i) a thorough clinical and radiological assessment of the limb before surgery and examination under anesthesia, (ii) appropriate bone cuts to correctly orient prostheses and restore normal alignment of the limb, (iii) equalising medial and lateral balance in flexion and extension by soft tissue releases and concomitant bony procedures and (iv) addressing associated bony defects and extra-articular deformity. Examples of each of these situations will be shown along with the technique deployed.
Results of conventional TKA in treating 173 knees with varus deformity exceeding 20o will be presented. Our technique of selective posteromedial release, reduction osteotomy of posteromedial tibial flare, sliding medial condylar osteotomy and bone grafting of medial defects, with preservation of medial collateral ligament integrity will be shown. The method of correcting extra-articular deformity will be depicted. With these techniques, mean tibiofemoral angle of 22.7 degrees varus pre-operatively (range 15–62) was corrected to 5.3 degrees valgus (range 2–9) post-operatively. 86% knees were in 4–10 degrees valgus post-operatively. Recent experience with CAS in treating over 200 patients with deformity exceeding 20 degrees will be presented along with the risk factors leading to malalignment.
Correction of severe varus deformity by the techniques reported can successfully restore alignment, painfree motion, and stability without the use of highly constrained implants.
