Tibia Valga Morphology in Osteoarthritic Knees: Importance of Preoperative Full Limb Radiographs in Total Knee Arthroplasty Ahmed Alghamdi, MD a , Michel Rahmé, MD b , Martin Lavigne, MD, MSc, FRCS c , Vincent Massé, MD c , Pascal-André Vendittoli, MD, MSc, FRCS c a King Fahad Medical City, Riyadh, KSA b Hôpital de Hautepierre, Strasbourg, France c Hôpital Maisonneuve-Rosemont, Montréal, Québec, Canada abstract article info Article history: Received 18 December 2013 Accepted 2 March 2014 Keywords: tibia valga genu valgum total knee arthroplasty knee morphology Osteoarthritis of the knee is associated with deformities of the lower limb. Tibia valga is a contributing factor to lower limb alignment in valgus knees. We evaluated 97 valgus knees and 100 varus knees. Long-leg films were taken in weight bearing with both knees in full extension. For valgus knees, 52 knees (53%) had a tibia valga deformity. Average tibia valgus deformation was 5.0°. For varus knees, there was only 1 case of tibia valga (1%), with a deformation of 2.5°. The aim of this study was to assess the prevalence of primary tibia valga in valgus and varus knees and understand how it affects our approach to total knee arthroplasty (TKA). We recommend having full-leg length films when planning for TKA in valgus knees. © 2014 Elsevier Inc. All rights reserved. Multiple risk factors have been linked to osteoarthritis (OA) in epidemiological studies [1–3]. Mechanical, biological, traumatic or a combination of these factors can lead to degenerative changes resulting in functional deterioration of the knee [2,3]. The degree of lower limb malalignment influences the rate of structural progression of degenerative changes in the arthritic knee [4,5]. One important measure of limb alignment is the hip–knee–ankle angle (HKA) [6–8]. The HKA defines the dynamic load distribution across the medial and lateral knee articular surfaces. In neutrally aligned limbs, the medial compartment bears 60% to 70% of the force across the knee during weight bearing [9,10]. The wide variation in lower limb alignments among normal individuals makes it difficult to define the normal spectrum [11]. The deviation from the neutral mechanical axis can arise from intra-articular or extra-articular deformities (the femur, the tibia or both) [12]. Historically, valgus knees have frequently been associated with distal metaphyso-epiphyseal femoral deformities (lateral condyle hypoplasia). In a study aiming to evaluate femoral hypoplasia as a cause of valgus knee, the average difference between medial and lateral condyles radii was 0.2 mm, with larger lateral than medial femoral condyle (P b 0.006) [13]. A valgus deformity of the tibial diaphysis was reported in one patient to be a contributing factor to the deviation of lower limb axis in a knee with valgus angulation [14]. In our practice we observed that such primary valgus deviation of the tibial diaphysis (not associated with any pathological cause or surgery) was present in many TKA cases performed for degenerative valgus knees. Therefore, we attempted to quantify the tibia valga prevalence and its contribution to overall lower alignment in valgus and varus arthritic knees and to evaluate its potential impacts on TKA procedure. Materials and Methods We retrieved from our database the patients operated for a TKA between 1994 and 2011. The operating surgeons classified the pre- surgery lower limb alignment as valgus or varus. Various methods have been utilized by each surgeon to classify the preoperative arthritic knee in our database based on overall alignment; those methods include combination of the physical examination [15] and the measurement of either/or both anatomic axis (6.85° ± 1.4°) [12,16] and mechanical axis using HKA [7]. In the neutrally aligned limb, the HKA angle approaches 180° (Varus deviations are negative HKA angle and valgus deviations are positive HKA angle) [17]. Inclusion criteria to the study group consisted of all patients of any age or gender with a full-leg hip to ankle preoperative radiographs in valgus mechanical axis alignment (Valgus alignment: knee center is medial to the line connecting the hip center to the centre of the talus (HKA is positive)) [17]. The inclusion and exclusion criteria were set so only idiopathic knee arthritis will be evaluated. Exclusion criteria included arthritic knees of traumatic or congenital cause, previous femoral or tibial osteotomy, previous fracture of the lower limb with or without internal fixation, and previous partial arthroplasty of the knee or total ankle arthroplasty. One hundred and thirty TKAs were preoperatively The Journal of Arthroplasty 29 (2014) 1671–1676 The Conflict of Interest statement associated with this article can be found at http:// dx.doi.org/10.1016/j.arth.2014.03.001. Reprint requests: Pascal-André Vendittoli, MD, MSc, FRCS, Hôpital Maisonneuve- Rosemont, 5415 Boul L'Assomption, Montréal, Québec, Canada, H1T 2M4. http://dx.doi.org/10.1016/j.arth.2014.03.001 0883-5403/© 2014 Elsevier Inc. All rights reserved. Contents lists available at ScienceDirect The Journal of Arthroplasty journal homepage: www.arthroplastyjournal.org