The clinical success and longevity of a primary total knee arthroplasty (TKA) in large part depend on our ability to control coronal alignment. However, controversy exists regarding which radiographs to use for the most accurate interpretation. The study assesses the accuracy of coronal alignment measurements using a single short knee radiograph (SKR) in comparison with full-length radiographs (FLRs).
Using our institutional database, we retrieved radiographs of all patients who have had pre- and postoperative FLRs for their primary TKA in 2014. The following measurements were obtained on both short and long radiographs: femoral-tibial angle (FTA), anatomic lateral distal femoral angle, medial proximal tibial angle, condylar-plateau angle, and condylar-plateau distance. A reliability analysis was conducted between the pre- and postoperative SKRs and FLRs using the intraclass correlation coefficient (ICC).
Radiographs of 236 limbs were included in the analysis. The FTA showed an ICC of 0.84 and 0.69 on the pre- and postoperative radiographs, respectively. Good ICC was seen in the lateral distal femoral angle in both the pre- and postoperative radiographs; these were 0.70 and 0.67, respectively. Also, the medial proximal tibial angle showed good to excellent correlation, with an ICC of 0.83 on the preoperative and 0.66 on the postoperative radiographs.
This study illustrates that SKRs could be an appropriate substitute for FLRs for the evaluation of primary TKA coronal alignment, especially in the postoperative assessment of these patients.
From the Division of Orthopaedic Surgery, Department of Surgery, London Health Sciences Centre University Campus, University of Western Ontario, London, Ontario, Canada (Dr. Alzahrani, Dr. Wood, Dr. Somerville, Dr. Howard, Dr. Lanting, Dr. Vasarhelyi), and the Department of Orthopaedic Surgery, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia (Dr. Alzahrani).
Correspondence to Dr. Alzahrani: email@example.com
Dr. Howard or an immediate family member is a member of a speakers' bureau or has made paid presentations on behalf of DePuy and Stryker; serves as a paid consultant to DePuy, IntelliJoint, and Stryker; has stock or stock options held in PersaFix Revision Technologies; has received research or institutional support from DePuy; and has received nonincome support (such as equipment or services), commercially derived honoraria, or other non–research-related funding (such as paid travel) from DePuy, Microport, Smith & Nephew, Stryker, and Zimmer. Dr. Lanting or an immediate family member serves as a paid consultant to DePuy, Integra, IntelliJoint, Smith & Nephew, and Stryker; has stock or stock options held in IdealFit Spacer Solutions and PersaFix Revision Solutions; has received research or institutional support from DePuy, Smith & Nephew, and Stryker; and has received nonincome support (such as equipment or services), commercially derived honoraria, or other non–research-related funding (such as paid travel) from DePuy, Smith & Nephew, Stryker, and Zimmer. Dr. Vasarhelyi or an immediate family member serves as a paid consultant to DePuy; has received research or institutional support from DePuy, Smith & Nephew, and Stryker. None of the following authors or any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this article: Dr. Alzahrani, Dr. Wood, and Dr. Somerville.