Background: There is a growing interest in TKA components alignment, especially around the kinematic technique, which aims at reestablishing the alignment of the native knee. However, the practical application of this technique has some limitations; (2) Methods: A series of consecutive full weight-bearing lower limbs radiographs performed in our Hospital without signs of osteoarthritis, post-traumatic deformities, and any previous surgical procedure (e.g. any joint replacement , osteotomy, anterior cruciate ligament reconstruction) were included. Several radiological parameters as the bisector line were measured by three members of our orthopedic unit and were then used to assess the inter-observer reliability.; (3) Results: 110 radiographic images belonging to 59 patients (both legs for 51 patients and one leg for 8 patients) were finally included in the present analysis. The bisector of the trochelar groove was perpendicular to the femoral joint line (mean 89.4°).; (4) Conclusions: The main finding of the current study was that the new anatomic landmark investigated, the bisector of the trochlear groove, was perpendicular to the femoral joint line viewed in the AP weight-bearing radiograph of the entire lower limbs of the healthy knee and therefore could potentially simplify the achievement of the kinematic alignment during a TKA procedure.

Kinesiophobia (fear of movement) has been recognized as a significant barrier to recovery and rehabilitation in patients after total knee arthroplasty (TKA). Our goal was to identify predictors of kinesiophobia and examine its correlation with early functional outcomes in TKA recipients. On the first and fifth postoperative days (POD1 and POD5), we evaluated pain using the International Pain Outcomes Questionnaire (IPO-Q) and created multidimensional pain composite scores (PCS). Pain Composite Score-total (PCStotal) assesses the overall impact of pain, taking into account outcomes of pain intensity, pain-related interference with function, and emotions and side effects. Functional status on POD 5 was determined by the Barthel index, 6-minute walking test, and knee range of motion. Kinesiophobia was measured on POD5 using the Tampa Scale for Kinesiophobia (TSK) and multivariable logistic regression was used to assess factors associated with kinesiophobia. Among 75 TKA patients, 27% exhibited kinesiophobia. The final regression model highlighted PCStotal on POD5 (OR=6.2, CI=1.9-19.9), PCStotal (OR=2.1, CI=1.2-3.8) on POD1, and the intensity of chronic pain before surgery (OR=1.4, CI=1.1-2.1) as significant kinesiophobia predictors. On POD5, those with kinesiophobia showed increased dependency, slower gait, and poorer knee extension recovery. This study highlights the importance of identifying and addressing kinesiophobia in TKA patients to optimize functional outcomes and improve recovery. Also, it is important to assess not only pain intensity but also the physical and emotional interference caused by pain, which can contribute to the development of kinesiophobia.

Background and objectives: Unrestricted kinematic alignment total knee arthroplasty (KA-TKA) with a soft tissue respecting technique (STRT) is a soft tissue-dependent tibial resection entailing restoration of the original soft tissue tension using ligamentotaxis after resurfacing the femur, based on the concept of restoring the native or pre-osteoarthritis alignment in each patient. However, there is no consensus on the indications of unrestricted KA-TKA with STRT. We modified the STRT, followed by investigation of the effects of surgery on the postoperative hip-knee-ankle angle (HKAA). Materials and Methods: We retrospectively analyzed the clinical background data, including the preoperative and postoperative HKAA, of 87 patients who underwent unrestricted KA-TKA with the modified STRT. Univariate and multivariate analyses were performed to determine the factors affecting the postoperative HKAA. A receiver operating characteristic (ROC) curve was plot-ted to investigate the change in the cut-off values of preoperative HKAA with respect to the safe zone of the postoperative HKAA. We generated two regression models, the linear regression model and generalized additive model (GAM) using machine learning, to predict the postopera-tive HKAA. Results: Univariate and multivariate analyses revealed the preoperative HKAA as the factor most relevant to the postoperative HKAA. ROC analysis revealed that the preoperative HKAA exhibited high predictive utility, with a cut-off value of -10°, when the safe range of postoperative HKAA was set at ± 5°. The GAM was the superior machine learning model, indicating a non-linear association between the preoperative and postoperative HKAA. Patients with preoperative HKAAs ranging from -18° to 4° were more likely to fall within the ± 5° safe range of the postoperative HKAA. Conclusions: The preoperative HKAA influences the postoperative HKAA in unrestricted KA-TKA with the modified STRT. Machine learning using the GAM may contribute to the selection of patients eligible for the surgical approach.