The significance of the pelvic incidence measurement as a possible predictor of TKA outcome

Abstract

Purpose To evaluate the association between the sagittal alignment of the pelvis and residual knee lexion contracture after total knee arthroplasty (TKA). This is important as a lexion contraction can be associated with the risk of poor outcomes and patient satisfaction after TKA. Methods This was a retrospective, case-control, study of 200 osteoarthritic knees, contributed by 200 patients, over a mean follow-up of 2.4 years. The following factors were compared between patients 'with' (46 knees) and 'without' (154 knees) a residual lexion contracture ≥ 10° after TKA: age, sex, pelvic incidence (PI), anterior femoral bowing, femoral component lexion angle (FFA), and patient-reported outcomes. Logistic regression and receiver operating characteristic curve analyses were used to identify predictive factors. ResultsThe following factors were predictive of a residual lexion contracture ≥ 10°: a pelvic incidence ≥ 55° (odds ratio, 1.29; 95% conidence interval, 1.05−1.59; P = 0.031) and the FFA (odds ratio, 1.08; 95% conidence interval, 1.03−1.14; P = 0.044). A pelvic incidence cutof of 55° yielded a signiicant between-group diference, with a sensitivity of 78.4% and speciicity of 89.9% to diferentiate a residual knee lexion contracture ≥ 10° (P = 0.001), patient satisfaction (P = 0.029), EuroQol 5-Dimension score (P = 0.028), anterior femoral curvature (P = 0.031), and Knee Injury and Osteoarthritis Outcome Score-Joint Replacement score (P = 0.046). Conclusion A pelvic incidence > 55° is associated with a residual knee lexion contracture ≥ 10° after TKA. The signiicance of the pelvic incidence measurement as a possible predictor of TKA outcome was highlighted, including its impact on patient satisfaction. Level of evidence III.

Restricted kinematically aligned total knee arthroplasty with an anatomically designed implant can restore constitutional coronal lower limb alignment

“…Particularly, the postoperative mLDFA, MPTA, and HKA converged to a varus phenotype within 3°, indicating reliability in restoring the knee by more closely approximating constitutional knee phenotypes [27]. Sagittal lower limb alignment in the standing position, especially the KFA, is important for physiological knee function, the pathology of knee osteoarthritis, and to improve a patient's quality of life [31][32][33]. However, there are few studies on sagittal lower limb alignment in TKA [34].…”

“…Sagittal lower limb alignment in the standing position, especially the KFA, is important for physiological knee function, the pathology of knee osteoarthritis, and to improve a patient's quality of life [31–33]. However, there are few studies on sagittal lower limb alignment in TKA [34].…”