Management of Extra-articular Deformity in the Setting of Total Knee Arthroplasty

Abstract

Extra-articular deformities of the femur and tibia in conjunction with advanced knee osteoarthritis pose unique challenges for the arthroplasty surgeon. Careful preoperative planning is needed to evaluate both the intra-and extra-articular deformities and to determine the best route to total knee arthroplasty. An intra-articular compensatory correction can typically be performed if the extraarticular deformity is distant from the joint or if preoperative templating shows that bony cuts do not interfere with ligamentous attachments. Staged osteotomy followed by arthroplasty is beneficial in severe cases in which bony cuts are excessive or would interfere with softtissue structures and in cases with leg-length discrepancy. Osteotomies can be performed percutaneously and fixed with intramedullary nails, external fixators, or plate and screw constructs. Ligamentous laxity after correction and risk of peroneal nerve injury are increased in extra-articular deformity cases and must be considered during the knee arthroplasty procedure with increased implant constraint and patient counseling, respectively. Computerassisted navigation has an emerging role in total knee arthroplasty in patients with extra-articular deformity. M ore than 700,000 total knee arthroplasties (TKAs) are performed annually in the United States. 1 Although correction of intra-articular pathology is a mainstay of TKA, less has been published on the evaluation and management of extra-articular deformity in the setting of TKA. An extra-articular deformity may be a result of previous trauma or skeletal developmental abnormalities and may increase the risk of knee osteoarthritis. 2 Thus, orthopaedic surgeons should be aware of the diagnosis and treatment algorithms for extraarticular deformity in the setting of TKA. Performing a TKA without addressing underlying extra-articular malalignment may place the patient at risk of ongoing pain and early implant failure. 3 The purpose of this article is to present treatment algorithms for the management of extra-articular deformity in either the femur or tibia and in the coronal, sagittal, or axial plane and to review the radiographic imaging, surgical planning, and multidisciplinary approach necessary to optimize clinical outcomes and minimize arthroplasty failure. Causes of Extra-articular Deformity of the Femur and Tibia and Its Association With Knee Osteoarthritis Causes of extra-articular deformity of the femur and tibia are numerous

One-Stage Total Knee Arthroplasty Plus Corrective Osteotomy for Osteoarthritis Associated With Severe Extra-articular Deformity

“…proposed that the amount of deformity and distance to the joint line determine the extension of bone resection and the optimal balance of the soft tissues to achieve a successful arthroplasty. The larger the deformity 12 and the closer it is to the joint, 13 the greater impact (stress) on the knee joint. The need to associate a corrective osteotomy to the TKA depends, in our opinion, on 2 factors: the magnitude of deformity and the distance of its apex to the joint line.…”

“…As a matter of fact, for this procedure, it is essential that the articular line that runs perpendicular to the mechanical axis of the femur or tibia does not intersect with the osseous insertion of collateral ligaments of the knee. This would imply the need to sacrifice them during surgery, destabilizing the joint, which is unacceptable 5, 12…”

“…However, when knee osteoarthritis is associated with severe EAD or an EAD that is far from the joint, a simple TKA could be insufficient to address both problems and ensure a functional and durable survival of the implant 5, 10. Currently, there are 3 options available for addressing this clinical situation: 2-staged surgical treatment (corrective osteotomy followed by TKA), 1-stage surgical treatment (simultaneous osteotomy and TKA), or a computer-assisted navigation TKA trying to avoid an extra-articular osteotomy to the TKA 11, 12…”

1-stage total knee arthroplasty and proximal tibial non-union correction using 3-D planning and custom-made cutting guide

“…Surgery was performed through a standard midline incision, which was extended distally and medially to join a previous incision, a medial parapatellar arthrotomy was used, and the Primary total knee arthroplasty (TKA) in the presence of extra-articular deformity and non-union is challenging (Papagelopoulos et al 2007, Sculco et al 2019. Bony correction can be staged prior to TKA surgery or simultaneously as a 1-stage procedure.…”

“… 2007 , Sculco et al. 2019 ). Bony correction can be staged prior to TKA surgery or simultaneously as a 1-stage procedure.…”