Techniques for managing anatomic variations in primary total knee arthroplasty.

Primary total knee arthroplasties have high success rates, but certain patient anatomic or other variations may adversely affect the performance or the clinical outcomes of these procedures. Various technologies and techniques have been developed in attempts to overcome these challenges. However, there is controversy concerning whether these innovations are beneficial. This article assessed the scientific evidence regarding the use of these technologies to address various anatomic variations by examining the complete body of literature. The anatomic variations that were examined included extra-articular deformities, bone deficiencies, ligamentous instability, post-patellectomy knees, patella baja, variations in bone size and high-flexion knees. Recommendations for each circumstance were presented based upon the available scientific evidence.