Femoral Lateral Bowing and Varus Condylar Orientation Are Prevalent and Affect Axial Alignment of TKA in Koreans

Abstract

Background Coronal alignment is considered key to the function and longevity of a TKA. However, most studies do not consider femoral and tibial anatomical features such as lateral femoral bowing and the effects of these features and subsequent alignment on function after TKA are unclear. Questions/purposes We therefore determined (1) the prevalence of lateral femoral bowing, varus femoral condylar orientation, and severe tibia plateau inclination in female Koreans undergoing TKA; (2) whether postoperative alignments are affected by these anatomical features and improved by the use of navigation; and (3) whether postoperative coronal alignments are associated with function.Methods We measured alignment in 367 knees that underwent TKA and 60 sex-and age-matched normal knees (control group). We determined patterns and degrees of femoral bowing angle, femoral condylar orientation, and tibial plateau inclination on preoperative full-limb radiographs. Postoperatively, coronal alignment of limbs and of femoral and tibial components was measured. We compared American Knee Society scores, WOMAC scores, and SF-36 scores in aligned knees and outliers (beyond ± 3°o r ± 2°) at 1 year. Results The prevalence of lateral femoral bowing was 88% in the TKA group and 77% in the control group. Mean femoral condylar orientation angle was varus 2.6°in the TKA group and valgus 1.1°in the control group, and mean tibial plateau inclination was varus 8.3°in the TKA group and varus 5.4°in the control group. Femoral lateral bowing and varus femoral condylar orientation were associated with postoperative alignments. Several clinical outcome scales were inferior in the outliers in mechanical tibiofemoral angle, anatomical tibiofemoral angle, and tibial coronal alignment but not in femoral coronal alignment outliers. Conclusions Lateral femoral bowing, varus condylar orientation, and severe varus inclination of the tibia plateau should be considered when performing TKA in Korean patients or patients with otherwise similar anatomical features.

Clinical Faceoff: Do We Need Special Strategies for Asian Patients with TKA?

“…Furthermore, if Asian patients have certain demographic and anatomical characteristics known to affect clinical outcomes, special strategies to accom modate the unique nature of Asian patients may be required for preoperative patient counseling, prosthesis design, surgical technique, and postoperative rehabilitation. At the same time, considering the wide variances reported even within the same ethnicity group [16,18,25], treating Asian patients undergoing TKA similarly to patients from the West may render better outcomes in function and longevity, because the Western patient population is generally a diverse group, and treatment has evolved to best accommodate this diversity.…”

“…TK Kim: Several previous studies reported that Asian patients seeking TKA for their advanced osteoarthritic knees present with different anatomical characteristics and deformity patterns, for example, more severe varus deformity and flexion contracture with yet well-preserved knee flexion [3,16]. To what degree should the same surgical principles, namely, creation of neutral limb alignment and balanced gaps, be preserved?…”

“…Simply choosing the center of the articular surface would result in varus alignment in some patients. Lateral bowing of the femur is another typical deformity in Asian patient [16]. In patients with severe deformities, we may need additional femoral osteotomy, either simultaneous or staged, along with TKA.…”

CORR ® International—Asia-Pacific: How To Live a Happy Life as an Orthopaedic Surgeon

“…(2) Decide what modifications should be made in postoperative rehabilitation protocols to accommodate the unexpected events during surgery. For example, vigorous medial ligament release, which is often required in TKA for Asian knees with severe varus deformity, sometimes end up with complete release of superficial MCL, subsequently causing medial instability [5,7]. This type of medial instability originating from complete release of superficial MCL, arguably can be treated by surgical repair without using constrained types of prostheses [9] or even bracing without additional surgical remedy [6].…”

CORR ® International—Asia-Pacific: Making the Transition From Training to Practice: A Guide For Young Surgeons in the Asia-Pacific Region

“…Certain surgical techniques may be more applicable in Asia than in the West. For Asian patients with TKA, additional surgical steps are more frequently required to address severe coronal or torsional deformity, which left untreated, can result in unbalanced asymmetrical gaps [3][4][5][6]. While ''traditional medicine'' may be a fad in the West, the ''traditions'' come from the East, and those traditions run long and deep in some parts of Asia.…”