What Is the Possible Impact of High Variability of Distal Femoral Geometry on TKA? A CT Data Analysis of 24,042 Knees

Abstract

Background Previous studies analyzing femoral components of TKAs have demonstrated the limited ability of these components to accommodate size variations seen in the patient population, particularly width and femoral offset. Questions/purposes The purpose of this study was to use a large data set of knee CT scans (1) to determine the variations in the distal and posterior femoral geometries and to determine whether there is a correlation between distal condylar offset and posterior femoral offset as a potential parameter for symmetry/asymmetry; and (2) to evaluate what proportion of knees would have a substantial mismatch between the implant's size or shape and the patient's anatomy if a femoral component of a modern standard TKA of symmetric (sTKA) or asymmetric (asTKA) designs were to be used. One of the authors (SZ) is an employee of Conformis Inc (Billerica, MA, USA). One of the authors certifies that he (AS) has received personal fees for consultant teaching, during the study period, in an amount of less than USD 10,000 from Conformis Inc, outside the submitted manuscript. One of the authors certifies that he (WK) has received or may receive research support and royalties, during the study period, in an amount of USD 10,000 to USD 100,000 from Conformis Inc, outside the submitted manuscript. One of the authors certifies that he (FK) has received personal fees and grants, during the study period, in an amount of less than USD 10,000 from Conformis Inc, outside the submitted manuscript. One of the authors certifies that he (JB) has received personal fees for consultant teaching, during the study period, in an amount of less than USD 10,000, from Smith & Nephew (Smith & Nephew GmbH, Hamburg, Germany) and personal fees for consultant teaching in an amount of less than USD 10,000 from Conformis Inc, all outside the submitted manuscript. Clinical Orthopaedics and Related Research® neither advocates nor endorses the use of any treatment, drug, or device. Readers are encouraged to always seek additional information, including FDA approval status, of any drug or device before clinical use. Each author certifies that his or her institution waived approval for the reporting of this investigation and that all investigations were conducted in conformity with ethical principles of research.

Undercoverage of lateral trochlear resection is correlated with the tibiofemoral alignment parameters in kinematically aligned TKA: a retrospective clinical study

“…The mismatch of the femoral component aspect ratio has been widely considered in TKA [ 31 ]; this issue is of course no exception in KA-TKA. In this study, if undercoverage was found both in distal femoral resection and lateral trochlear resection, then the femoral component was appropriately lateralized to reduce the extent of lateral trochlear resection undercoverage.…”

The Use of Customized Total Knee Arthroplasty Implants to Increase Efficiency in the Operating Room and Improve Patient Outc

“…There is now over a decade of experience with customized implants, including over 100,000 implantations worldwide. Previous peer-reviewed studies confirm that patient specific TKA implants provide improved fit and alignment 9,10,11,12 , better kinematic function 13,14 , reduced short-term complication rates 15,16 , higher patient satisfaction 17,18 , and overall cost savings 15,16,19,20 when compared to standard off the shelf implants. Data from the UK National Joint Registry (UKNJR), recently released by Beyond Compliance, highlight a lower cumulative revision rate for the custom cruciate retaining implants than that of all other knee implants in the UKNJR 21 .…”

True Kinematic Alignment Is Applicable in 44% of Patients Applying Restrictive Indication Criteria—A Retrospective Analysis of 111 TKA Using Robotic Assistance

“…it is questioned whether it makes sense to reconstruct pathologic situations that have led to osteoarthritis, or to better correct these with surgery. Another point of criticism is whether it is possible to properly reconstruct the individual joint surface with the use of a standard, symmetric prosthesis or if the different patient morphologies might require an individualized prosthesis [ 6 , 7 ]. Thus, not all patients may be suitable for KA TKA.…”