Background: Femorotibial rotational mismatch can occur when there is a rotational malalignment in either the tibial or femoral component. Self-aligned technique was proposed for orienting the tibial component in relation to the femoral prosthesis to reduce rotational malalignment between components. Therefore, we aimed to compare the rotational angle of the femoral and tibial components, as well as the femorotibial rotational mismatch, between the measured resection (MR) and gap-balancing (GB) techniques when combined with a self-aligned technique. Methods: We conducted a nonrandomized, experimental study with 50 patients in each group. The femoral rotation was set to 3° external rotation relative to the posterior condylar axis in the MR group, whereas the femur was resected to obtain an optimal rectangular flexion gap in the GB group. The self-aligned method was used to set the tibial rotation in both groups. Femoral and tibial rotational alignments were evaluated compared to a surgical transepicondylar axis of the femur using computed tomography.Rotational mismatch was defined as a difference between the femoral and tibial rotational alignments. A positive value indicated that the component was externally rotated relative to the reference line. Results: The femoral component of the GB group was more externally rotated than that of the MR group (1.52° ± 1.31° vs 0.28° ± 1.16°, p < 0.001). However, the tibial rotational angle was not statistically significantly different between the MR and GB groups (1.28° ± 3.17° vs. 1.86° ± 2.81°, p = 0.220), and the rotational mismatch was 1.00° ± 3.28° and 0.34° ± 2.71°, respectively ( p = 0.306). Conclusions Although the femoral component of the GB group had a greater degree of external rotation than that of the MR group, the use of a self-aligned technique for tibial component placement resulted in no significant difference in tibial rotational alignment or rotational mismatch. This technique helps align the tibial component with the femoral component and lessen the degree of rotational malalignment in both the MR and GB techniques.

Background: The main objective of treating fragility hip fractures is to maximize the patients’ ability to return to their basic activities of daily living (ADL) levels. This study explored prognostic factors associated with the ability to recover pre-fracture ADL levels at 1 year after fragility hip fractures. Methods: We retrospectively recruited patients admitted with fragility hip fractures between July 2016 and September 2018. Details of the following were extracted from electronic medical records: age, sex, body mass index; pre-fracture Charlson Comorbidity Index (CCI), Barthel index, and EuroQol-Visual Analog Scale (EQ-VAS) scores; pre-fracture ambulatory status; and fracture type and treatment. The primary endpoint was the ability to return to the pre-fracture ADL status at 1 year. Multivariable logistic regression analysis assessed the prognostic ability of predictors. Results: Of 405 patients, 284 (70.1%) managed to return to their pre-fracture ADL status. Multivariable logistic regression analysis demonstrated that the predictor with the most apparent effect size was pre-fracture EQ-VAS scores ≥ 65 (multivariable odds ratio [mOR], 12.90; p = 0.03). Other influential predictors were CCI scores < 5 (mOR, 1.96; p = 0.01) and surgical treatment for the hip fracture. Conclusions Three prognostic factors can predict a hip fracture patient’s ability to return to the pre-fracture ambulatory status at 1 year. They are the patient’s CCI score, operative treatment for the hip fracture, and the pre-fracture EQ-VAS score. This information could be used to develop a clinical prediction model based on the prognostic factors.