RESUMO
BACKGROUND: Proper tibial alignment is an important goal of total knee arthroplasty. Most surgeons agree that tibial coronal alignment should be within three degrees of neutral mechanical alignment. The "midsulcus line" is a line drawn along the sulcus of the tibial spines, and then the line is continued in the sagittal plane and extended onto the anterior tibia where it intersects the tibial tubercle approximately 3 to 4mm lateral to the tubercle's medial border. The tibial cut was then made perpendicular to this line. The aim of our study was to assess, using CT scans, whether this line provided a consistent guide for planning the tibial cut in total knee arthroplasty. METHODS: We reviewed the CT scans of the knees of 107 patients with osteoarthritis who had undergone a CT scan for planning of custom cutting guides. The midsulcus line was drawn on all scans. RESULTS: We found that in 105 of 107 knees, a perpendicular cut to this tibial landmark would have delivered a cut surface within three degrees of neutral mechanical alignment. CONCLUSIONS: The midsulcus line is a reliable landmark for planning the tibial resection in total knee arthroplasty. LEVEL OF EVIDENCE: III.
Assuntos
Artroplastia do Joelho/métodos , Mau Alinhamento Ósseo/prevenção & controle , Tíbia/diagnóstico por imagem , Tíbia/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Artroplastia do Joelho/efeitos adversos , Mau Alinhamento Ósseo/etiologia , Feminino , Humanos , Imageamento Tridimensional , Masculino , Pessoa de Meia-Idade , Osteoartrite do Joelho/diagnóstico por imagem , Osteoartrite do Joelho/cirurgia , Tomografia Computadorizada por Raios XRESUMO
Proper mechanical and rotational alignment plays an important role in achieving the success of the total knee arthroplasty (TKA). The purpose of the present study was to retrospectively determine with computed tomography (CT) the distal femoral valgus angle (DFVA) and femoral rotation angle (FRA). Our cohort included 13,546 CT scans of patients undergoing TKA. The average DFVA was 5.7 ± 2.3° (range from 1 to -16°) with 13.8% of patients identified as outliers. The distal FRA angle average was 3.3 ± 1.5° (range from -3 to 11°) with 2.8% of patients identified as outliers. These data can be useful in making orthopedic surgeons aware of the variability of femoral anatomy. Using the same cutting angle may lead to malposition of the femoral component.
