BackgroundRestoring the normal joint line (JL) is an important goal to achieve in total knee arthroplasty (TKA). We intended to study the veracity of several landmarks used to level the normal JL in Chinese people.MethodsTwo hundred fifteen standard CT scans of knee joint were included to measure the distances from landmarks to distal JL (DJL) and posterior JL (PJL), along with femoral width (FW) in order to calculate the ratios. Landmarks included adductor tubercle (AT), medial epicondyle (ME), lateral epicondyle (LE), tibial tubercle (TT), fibular head (FH) and the inferior pole of the patella (IPP). Ratios were calculated between distances and FW (e.g. FHDJL/FW). Linear regression analysis and t test were used to determine the accuracy and the differences amongst sides of the leg, genders and races.ResultsThe average of IPPDJL/FW, TTDJL/FW, FHDJL/FW, LEDJL/FW, LEPJL/FW, MEDJL/FW, MEPJL/FW, ATDJL/FW and ATPJL/FW were 0.165, 0.295, 0.232, 0.297, 0.281, 0.327, 0.3PJL, 0.558 and 0.313, respectively. No significant difference had been found between the left and right leg. A gender difference was only found statistically on the ratio of IPP, and also, no linear correlation was observed only between IPP and FW. Most of the difference values lain in a 4-mm threshold for MEDJL (95.81%), LEDJL (94.88%), MEPJL (97.21%), LEPJL (94.88%), ATPJL (93.49%) and ATDJL (100%). Significant differences were observed amongst different races.ConclusionsAT, ME and LE can be used as reliable landmarks to locate the normal JL in Chinese population intraoperatively. It is meaningful to come up with a set of ratios to different races.

Background: Despite the continued improvement in the surgical techniques during primary total knee arthroplasty (TKA), literatures indicate that up to 10 to 20% patients are not satisfied with their outcomes. Psychological factors in this dissatisfaction are yet to be clearly identified. The aim of this study is to develop a method to assess whether the patient's current mental state is suitable enough to accept a TKA surgery. Methods: Preoperative demographic and clinical data of 532 patients who underwent TKA were prospectively obtained from January 2012 until December 2016. We recorded the scores evaluated by SF-36 questionnaire and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) preoperatively and 1 year postoperatively. Preoperative Life Satisfaction Rating (LSR) is emphatically evaluated. Results: Poor preoperative score of LSR was a significant predictor of dissatisfaction after TKA. Patients with low LSR reported significant pain and stiffness, although there was no remarkable effect on functionality of the replaced joint. The results also showed that age and BMI were not strong predictors of satisfaction in TKA. Conclusion: Our outcomes can help clinicians evaluate whether a patient's current mental status is favorable for TKA. If patients have extreme low scores of LSR (less than 10), a psychological intervention should be recommended for better satisfaction following a TKA surgery. This would also allow surgeons to individually assess the risks and benefits of surgery.

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