Concordance in Radiological Parameters of Different Knee Views After Total Knee Arthroplasty

Abstract

Background Total knee arthroplasty (TKA) is a cost-effective treatment for the end-stage of knee osteoarthritis. Despite the improvements in this surgery, a significant percentage of patients still report dissatisfaction after knee arthroplasty. Radiological results have been used to predict clinical outcomes and satisfaction after knee replacement. This study aims to evaluate the concordance of a set of radiographic views to assess alignment on total knee arthroplasty. Methods A concordance study was designed with 105 patients (130 TKA) that underwent conventional total knee arthroplasty cruciate-retaining design recruited for the study and scheduled for their annual radiograph control. Measurements were performed on the following radiograph after total knee replacement: full-length standing anteroposterior and lateral radiograph, anteroposterior standing, lateral and axial knee view, and the knee "seated view". A musculoskeletal radiologist and a knee surgeon were recruited to perform the radiological measurement and then estimate the interobserver agreement. Results There was an excellent correlation between Limb Length (LL), Hip-knee-ankle angle (HKA), Sagittal mechanical tibial component alignment (smTA), extension lateral and medial joint space (eLJS and eMJS), 90º flexion lateral and medial joint space (fLJS and fMJS) and Sagittal anatomic lateral view tibial component alignment (saLTA); the good correlation between Mechanical lateral femoral component alignment (mLFA), Sagittal anatomic tibial component alignment (saTA), Sagittal anatomic lateral view femoral component alignment 2 (saLFA2), Patella Height (PH); and moderate to poor correlation for the rest of measurements. Conclusion Excellent and good concordance can be achieved for radiographic measurements in different knee views to assess results after TKA. These findings must encourage future studies to address functional and survival outcomes using all knee views and not just one plane.

Keywords: knee replacement; patient; radiograph; satisfaction; total knee arthroplasty.

Figure 1. Full-length standing anteroposterior radiograph

(a) Limb length (yellow line), the hip-knee-ankle angle (green line); (b) Mechanical lateral femoral component alignment, and mechanical medial tibial component alignment.

Figure 2. Full-length standing lateral radiograph

(a)Sagittal anatomic femoral component alignment 1; (b) Sagittal anatomic femoral component alignment 2; (c) Sagittal mechanical femoral component alignment 1; (d) Sagittal mechanical femoral component alignment 2; (e) Sagittal anatomic tibial component alignment; (f) Sagittal mechanical tibial component alignment

Figure 3. Anteroposterior standing knee view

(a) Extension lateral and medial joint space; (b) Extension joint angle

Figure 4. Seated view

(a) 90º flexion lateral and medial joint space; (b) 90º flexion joint angle; (c) Femoral component rotation

Figure 5. Lateral knee radiograph

(a) Sagittal anatomic lateral view femoral component alignment 1; (b) Sagittal anatomic lateral view femoral component alignment 2; (c) Sagittal anatomic lateral view tibial component alignment; (d) Patela Height (yellow line). Patela Height 2 (green line); (e) Offset femoral anterior; (f) The anterior inclination angle of the femoral component

Figure 6. Axial knee radiograph

(a) Patellar lateralization distance; (b) Opening lateral patellar angle; (c) Patellar tilt angle; (d) Patellofemoral joint space; (e) Lateral patellar overhanging