Abstract
Soft-tissue release plays an integral part in primary total knee arthroplasty by ‘balancing’ the knee. Asian patients often present late and consequently may have large deformities due to significant bone loss and contractures medially, and stretching of the lateral collateral ligament. Extra-articular deformities may aggravate the situation further and make correction of these deformities more arduous.
Several techniques have been described for correction of deformity by soft-tissue releases. However, releasing the collateral ligament during TKA has unintended consequences such as the creation of significant mediolateral instability and a flexion gap which exceeds the extension gap; both of these may require a constrained prosthesis to achieve stability. We will show that soft-tissue balance can be achieved even in cases of severe varus deformity without performing a superficial medial collateral ligament release.
The steps are: Determining pre-operatively whether deformity is predominantly intra-articular or extra-articular; Individualizing the valgus resection angle and bony resection depth; Reduction osteotomy, posteromedial capsule resection, sliding medial condylar osteotomy, extra-articular corrective osteotomy; Compensating for bone loss; Only rarely deploying a more constrained device.
Case examples will be presented to illustrate the entire spectrum of varus deformities.
