THE KNEE SOCIETY VIRTUAL FELLOWSHIP

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1 THE KNEE SOCIETY VIRTUAL FELLOWSHIP CHAPTER 2: RADIOGRAPHIC EVALUATION OF THE KNEE Radiographic Evaluation of the Knee Presented by: R. Michael Meneghini, MD COPYRIGHT 2016 THE KNEE SOCIETY

2 Disclosures Consulting Payments / Royalties DJO OsteoRemedies PixarBio Investment / Ownership Shares IU Health Saxony ASC Research Support NIH R15 IU School of Medicine Foundation Fellowship Funding OMEGA Editorial Boards Journal of Arthroplasty

3 RADIOGRAPHIC EVALUATION OF THE NATIVE KNEE Standing Bilateral Weight Bearing AP: Used to assess degree and location of disease and in particular joint space narrowing. Bilateral exams recommended for a comparison with unaffected side for more accurate correlation of symptoms to radiographic changes. Weight-bearing views more accurately assess the joint space loss compared with supine views COPYRIGHT 2016 THE KNEE SOCIETY

4 RADIOGRAPHIC EVALUATION OF THE NATIVE KNEE COPYRIGHT 2016 THE KNEE SOCIETY Bilateral PA Flexion Weight Bearing: Recommended to assess the posterior femoral condylar cartilage and is found to be more accurate, sensitive and specific. It is obtained with the patient standing, knees flexed to 45-degrees and patella touching the cassette. The x-ray beam is directed 10 degrees caudad directed at the inferior patellar pole.

5 RADIOGRAPHIC EVALUATION OF THE NATIVE KNEE Lateral: Used to assess peri-articular osteophytes, patellar anatomy, patella tendon length (Insall-Salvati ratio), tibial slope, joint-line position. Is obtained with the knee flexed 30-degrees lying on the affected side. COPYRIGHT 2016 THE KNEE SOCIETY

6 RADIOGRAPHIC EVALUATION OF THE NATIVE KNEE Bilateral Patellofemoral (Merchant) View: The preferred view is the Merchant view used to evaluate patellofemoral position, alignment and patellar anatomy. Obtained with the patients lying supine knees flexed to 45-degrees, held with a fixed or adjustable platform, the x-ray beam angled 30 degrees from the horizontal COPYRIGHT 2016 THE KNEE SOCIETY

7 HIP TO ANKLE PLAIN RADIOGRAPHS May be used to assess extraarticular deformity and overall limb alignment May be indicated if history of diaphysial extra-articular trauma or childhood procedures COPYRIGHT 2016 THE KNEE SOCIETY

8 KNEE SOCIETY RADIOGRAPHIC SCORE In 1989, The Knee Society developed clinical [1] and radiographic [2] evaluation systems to support standardized research on total knee arthroplasty (TKA) outcomes. An updated version of The Knee Society Clinical Rating System was published in [3, 4] 1. Insall JN, Dorr LD, Scott RD, Scott WN. Rationale of the Knee Society clinical rating system. Clinical Orthopaedics and Related Research. 1989: Ewald FC. The Knee Society total knee arthroplasty roentgenographic evaluation and scoring system. Clinical Orthopaedics and Related Research. 1989: Noble PC, Scuderi GR, Brekke AC, Sikorskii A, Benjamin JB, Lonner JH, Chadha P, Daylamani DA, Scott WN, Bourne RB. Development of a new Knee Society scoring system. Clinical Orthopaedics and Related Research. 2012;470: Scuderi GR, Bourne RB, Noble PC, Benjamin JB, Lonner JH, Scott WN. The new Knee Society Knee Scoring System. Clinical Orthopaedics and Related Research. 2012;470:3-19.

9 KNEE SOCIETY RADIOGRAPHIC SCORE The purpose of this study was to develop a modernized and updated radiographic evaluation for TKA to accompany the new clinical Knee Society Score. Modernization was especially important in light of the diverse variety of knee designs that have emerged in the past 25 years.

10 METHODS Committee of six Knee Society members formed to develop an updated radiographic assessment and evaluation system. Systematic, Boolean search of EMBASE, CINAHL-plus, PubMed, and SCOPUS performed to identify TKA radiographic literature from January 1980 through September Based on literature review, a modernized and updated radiographic evaluation system was developed for both primary and revision TKA. Distributed to Knee Society membership for evaluation and feedback. Feedback was incorporated into the Knee Society Radiographic Evaluation System presented here.

11 Measuring Coronal and Sagittal Alignment Component Position Schematic of coronal plane radiographic measurements (in degrees) that denote femoral and tibial anatomic axis based on the implant alignment.

12 Measuring Coronal and Sagittal Alignment Component Position Schematic of sagittal plane radiographic measurements (in degrees) that denote femoral component flexion and tibial slope.

13 Measuring Coronal and Sagittal Alignment, Component Position (A) Radiographic patella tilt measurement (in degrees) relative to the femoral component denoted on the Merchant view radiograph. (B) Radiographic patella displacement measurement (in millimeters) relative to the central trochlea of the femoral component denoted on the Merchant view radiograph.

14 Implant Zone Classification for Documenting Deficiencies (A) Coronal and (B) sagittal radiographic schematic of keeled and two-peg implants with zones for documentation of radiolucent lines and osteolysis. (C) Sagittal plane radiographic schematic of femoral implant with zones denoted for documentation radiolucent lines and osteolysis. * Radiolucent lines should be denoted and documented as partial or complete and osteolysis documented in millimeters.

15 Implant Zone Classification for Documenting Deficiencies Patellofemoral view radiographic schematic of multi- or single-peg patella implant with zones denoted for documentation of radiolucent lines and osteolysis. * Radiolucent lines should be denoted and documented as partial or complete and osteolysis documented in millimeters.

16 Implant Zone Classification for Documenting Deficiencies Revision Implants (A) Coronal and (B) sagittal radiographic schematic of revision tibial implants that have stem extensions with zones for documentation of radiolucent lines and osteolysis. (C) Coronal and (D) sagittal radiographic schematic of revision femoral implants that have stem extensions with zones for documentation of radiolucent lines and osteolysis. Radiolucent lines should be denoted and documented as partial or complete and osteolysis documented in millimeters.

17 Implant Zone Classification for Documenting Deficiencies Patellofemoral radiographic view schematic denoting patella bone thickness, measured in millimeters.

18 Evaluating Implant Fixation: Radiolucent Lines and Osteolysis Examine AP, lateral, and patellofemoral radiographs for radiolucent lines. Examine the implant-cement and cement-bone interfaces, and the implant-bone interface in uncemented implants.

19 Evaluating Implant Fixation: Radiolucent Lines and Osteolysis Grade lucent lines as partial or complete with respect to the zones presented earlier and again below. Document regions of osteolysis in millimeters by zone.

20 Evaluating Implant Fixation: Radiolucent Lines and Osteolysis Determine whether radiolucent lines are stable or progressive on serial radiographs. Perform serial radiographs with nearly identical implant orientations, limb positions, and radiographic projections.

21 ADDITIONAL STUDIES: COMPUTED TOMOGRAPHY COPYRIGHT 2016 THE KNEE SOCIETY Not routinely used, but may be useful in certain situations: Evaluation of femoral and tibial implant rotation Evaluation of peri-prosthetic osteolysis Plain radiographs typically underappreciate the full extent of osteolytic lesions MRI is an additional option for evaluation of peri-articular osteolysis

22 ADDITIONAL STUDIES: NUCLEAR BONE SCAN Not routinely used, but may be useful in certain situations: Loosening that may not be obvious on plan radiographs (ie. debonding) WBC-tagged combined with Sulfur-colloid Scan may be helpful to identify infection COPYRIGHT 2016 THE KNEE SOCIETY

23 CONCLUSIONS This new radiographic evaluation system focuses on uniformity of assessment and documentation. Future research efforts should focus on the collection of standardized data to formulate criteria or scores to identify when TKA implants are at risk.