BACKGROUND: Distal femur fractures remain treatment challenges with a considerable postoperative non-union rate. Concern remains that surgery may compromise osseous vascularity. This study aimed to determine effects of retrograde femoral intramedullary nailing (RFIN) on distal femur vascularity, and the locations of the middle genicular artery terminal branches in relation to the standard RFIN entry point.
METHODS: Five lower limb cadaveric pairs were obtained (ten specimens). Experimental limbs were randomly assigned, and contralateral limbs served as controls. An 11 mm femoral nail was implanted in experimental specimens. Controls only underwent a medial parapatellar incision with capsulotomy. Quantitative pre- and post-contrast-MRI was performed to assess arterial contributions to distal femur regions. Osseous vascularity was further evaluated with contrast-CT imaging. Next, specimens were injected with latex medium, and dissection was performed to assess extraosseous vasculature.
RESULTS: No statistically significant differences were found with quantitative-MRI in experimental and control groups for the entire distal femur or individual regions. The experimental group demonstrated a small mean decrease of 1.4% in distal femur arterial contributions. CT and anatomic dissection confirmed maintenance of middle genicular artery terminal branches. On average, 3.3 (±1.3) terminal branches entered along the posterior intercondylar notch. A mean distance of 15.2 mm (±6.9 mm) was found between the posterior RFIN entry point and these terminal branches.
CONCLUSIONS: RFIN did not significantly alter arterial contributions to the distal femur or disrupt the middle genicular artery terminal branches. However, care must be taken to ensure nail entry point accuracy given proximity of the entry point to terminal branches.

BACKGROUND: Fractures of the distal femoral third are an important cause of morbidity and mortality, and their treatment is currently controversial.
OBJECTIVE: To compare the results between minimally invasive techniques versus exposure of the fracture site. Secondly, to evaluate the relationship between demographic factors, mechanism of injury and surgical delay with patient prognosis.
METHODS: Retrospective cohort study carried out between 2015 and 2021 in a tertiary hospital. Data collection was performed by reviewing medical histories, measuring demographic and hospital parameters and definitive treatment strategy. One year of follow-up was completed in all patients, assessing the occurrence of surgical complications and mortality. A stratified analysis of the variables of interest was performed among patients over 65 years of age.
RESULTS: 128 fractures were recorded, with definitive osteosynthesis being performed in 117. Patients who underwent minimally invasive techniques required a shorter hospital stay (9 [7-12] vs. 12 [8.75-16] days) (p=0.007), with no differences in mortality or complications during follow-up. In those over 65 years of age, opening the fracture site was associated with an increased risk of infection compared to minimally invasive techniques (33.3% vs. 2%) (p=0.507). All the deceased were patients over 65 years of age (33.7% at one year). Surgical delay longer than 48h increased mortality by 10% among those older than 65 years (p=0.3). High-energy trauma had a higher proportion of pseudarthrosis (27.6% vs. 6.1%) (p=0.011).
CONCLUSIONS: Minimally invasive techniques decreased hospital stay but not complications or long-term mortality.
METHODS: IIb.

OBJECTIVE: This cohort study aimed to describe the functional outcomes, complications, and mortality of patients over 65 with acute distal femur fractures treated with open reduction and internal fixation (ORIF) or distal femoral replacement (DFR).
METHODS: We retrospectively analyzed all patients older than 65, operated consecutively for a distal femur fracture treated with ORIF or DFR. We included 75 patients (9 33A, 5 33B, and 61 33C AO/OTA fractures), 55 treated with ORIF, and 20 with DFR. We used Parker\'s mobility index (PMI) to assess functional outcomes at 1, 3, and 12 months and study closure. We analyzed complications, reoperations, and mortality at 30 days, one year, and at the end of the study.
RESULTS: The PMI was significantly higher in the DFR group at months 1 (p = 0.023) and 3 (p = 0.032). We found no significant differences between cohorts at one year and the end of follow-up. Postoperative complications were significantly more frequent in the ORIF group (38.10% vs. 10%, p = 0.022). Reoperations were similar in both cohorts (p = 0.98). Mortality at one month was 4% and 20% at one year, and at the end of follow-up, there were no significant differences between groups.
CONCLUSIONS: The outcomes of this study suggest that DFR offers a faster functional recovery with lower complication rates than those treated with ORIF. Additionally, both options have similar reoperation and mortality rates. Appropriately designed studies are needed to define the best treatment strategy for this type of patient.

BACKGROUND: Fractures of the distal femoral third are an important cause of morbidity and mortality, and their treatment is currently controversial.
OBJECTIVE: To compare the results between minimally invasive techniques versus exposure of the fracture site. Secondly, to evaluate the relationship between demographic factors, mechanism of injury and surgical delay with patient prognosis.
METHODS: Retrospective cohort study carried out between 2015 and 2021 in a tertiary hospital. Data collection was performed by reviewing medical histories, measuring demographic and hospital parameters and definitive treatment strategy. One year of follow-up was completed in all patients, assessing the occurrence of surgical complications and mortality. A stratified analysis of the variables of interest was performed among patients over 65 years of age.
RESULTS: 128 fractures were recorded, with definitive osteosynthesis being performed in 117. Patients who underwent minimally invasive techniques required a shorter hospital stay (9 [7-12] vs. 12 [8.75-16] days) (p=0.007), with no differences in mortality or complications during follow-up. In those over 65 years of age, opening the fracture site was associated with an increased risk of infection compared to minimally invasive techniques (33.3% vs. 2%) (p=0.507). All the deceased were patients over 65 years of age (33.7% at one year). Surgical delay longer than 48hours increased mortality by 10% among those older than 65 years (p=0.3). High-energy trauma had a higher proportion of pseudarthrosis (27.6% vs. 6.1%) (p=0.011).
CONCLUSIONS: Minimally invasive techniques decreased hospital stay but not complications or long-term mortality.
METHODS: IIb.

BACKGROUND: The stiffness of locked plates suppresses healing process, prompting the introduction of far cortical locking to address this issue. This study aimed to demonstrate the clinical efficacy of far cortical locking constructs in treating distal femoral fractures in an Asian population.
METHODS: This multicenter prospective observational study was conducted at four university hospitals between February 2018 and February 2021. Demographic data, the presence of metaphyseal comminution, and surgical fixation details were recorded. Clinical outcomes, including single-leg standing, EQ-5D, and EQ-VAS scores, and radiologic outcomes, including the RUST score of each cortex, were evaluated and compared according to the presence of metaphyseal comminution.
RESULTS: There were 37 patients (14 men and 23 women) with a mean age of 67.3 ± 11.8 years. Twenty-two patients had metaphyseal comminution (59%), and 15 presented simple fractures in metaphyseal areas. Four patients (13%) could stand on one leg >10s at 6 weeks, and 24 patients (92%) at 1 year. EQ-5D increased from 0.022 ± 0.388 to 0.692 ± 0.347, and the mean EQ-VAS 51.1 ± 13.1 to 74.1 ± 24.1 between discharge (n = 37) and post-operative 1 year (n = 33), respectively. RUST score presented increment for time, from 6.2 ± 1.8 at 6 week to 11.6 ± 1.1 at 1 year. Radiological healing demonstrated rapid increase from week 6 (16/28, 43%) to month 3 (27/31, 87%), with no obvious increase was observed in 6 months (23/26, 89%) or 12 months (25/28, 89%). Simple metaphyseal fractures presented significantly higher RUST scores at 6 weeks and 3 months, but there was no difference in RUST scores at 6 months or 1 year according to metaphyseal comminution.
CONCLUSIONS: Plate constructs with far cortical locking screws provided safe and effective fixation for distal femoral fractures, with consistent radiological and clinical results, regardless of metaphyseal comminution.

Purpose: Correctly classifying distal femur fractures is essential for surgical treatment planning and patient prognosis. This study assesses the potential of Cinematic Rendering (CR) in classifying these fractures, emphasizing its reported ability to produce more realistic images than Volume Rendering (VR). Methods: Data from 88 consecutive patients with distal femoral fractures collected between July 2013 and July 2020 were included. Two orthopedic surgeons independently evaluated the fractures using CR and VR. The inter-rater and intra-rater agreement was evaluated by using the Cicchetti-Allison weighted Kappa method. Accuracy, precision, recall, and F1 score were also calculated. Diagnostic confidence scores (DCSs) for both imaging methods were compared using chi-square or Fisher\'s exact tests. Results: CR reconstruction yielded excellent inter-observer (Kappa = 0.989) and intra-observer (Kappa = 0.992) agreement, outperforming VR (Kappa = 0.941 and 0.905, respectively). While metrics like accuracy, precision, recall, and F1 scores were higher for CR, the difference was not statistically significant (p > 0.05). However, DCAs significantly favored CR (p < 0.05). Conclusion: CR offers a superior visualization of distal femur fractures than VR. It enhances fracture classification accuracy and bolsters diagnostic confidence. The high inter- and intra-observer agreement underscores its reliability, suggesting its potential clinical importance.

(1) Background: Bone healing is influenced by various mechanical factors, such as stability, interfragmentary motion, strain rate, and direction of loading. Far cortical locking (FCL) is a novel screw design that promotes bone healing through controlled fracture motion. (2) Methods: This study compared the outcome of distal femur fractures treated with FCL or SL (standard locking) screws and an NCB plate in a randomised controlled prospective multicentre trial. The radiographic union scale (RUST) and healing time was used to quantify bone healing on follow-up imaging. (3) Results: The study included 21 patients with distal femur fractures, 7 treated with SL and 14 treated with FCL screws. The mean working length for patients with SL screws was 6.1, whereas for FCL screws, it was 3.9. The mean RUST score at 6 months post fracture was 8.0 for patients with SL plates and 7.3 for patients with FCL plates (p value > 0.05). The mean healing time was 6.5 months for patients with SL plates and 9.9 months for patients with FCL plates (p value < 0.05). (4) Conclusions: Fractures fixed with SL plates had longer working lengths and faster healing times when compared to FCL constructs, suggesting that an adequate working length is important for fracture healing regardless of screw choice.

BACKGROUND: Geriatric fractures including distal femur and hip fractures are associated with high mortality rates. Currently, prognostic factors for in-hospital postoperative mortality are not identified. We aimed to evaluate overall in-hospital mortality and related potential risk factors in elderly patients who underwent distal femur fracture surgery.
METHODS: A retrospective cohort study of patients older than 60 years, who underwent distal femur fracture surgery between January 01, 2003, and December 31, 2021, was conducted. A case-control study was conducted to compare two age-matched groups of elderly patients of equivalent ages at a 1:4 ratio. The in-hospital mortality rate was calculated and potential confounders were compared between groups.
RESULTS: A total of 170 patients were enrolled; five died during hospital stay after undergoing surgery, yielding a 2.94% in-hospital mortality rate. Twenty patients who did not die were included in the control group. Patients\' demographics were similar. The case-control comparison showed that the time from injury to surgery, preoperative hemoglobin level, estimated glomerular filtration rate (eGFR), and white blood cell count were significant factors correlated with in-hospital mortality.
CONCLUSIONS: The overall in-hospital mortality rate was 2.94%. Significant risk factors for in-hospital mortality included a longer time from injury to surgery, lower preoperative hemoglobin level and eGFR, and higher preoperative white blood cell count. In conclusion, preoperative comprehensive geriatric assessment, including cognitive, nutritional, and frailty status, should also be considered in the elderly fracture care model.

OBJECTIVE: Distal femur fractures (DFF) are rare, but associated with high complication rates and mortality, particularly in patients with osteoporosis. To improve preoperative assessment, we analyzed if cortical bone thickness on CT and AP radiographs is associated with clinical parameters of bone quality.
METHODS: Retrospective single-center study of adult patients presenting at a level-one trauma center, with a DFF between 2011 and 2020. Clinical parameters for bone quality, such as age, sex, body mass index (BMI), energy impact level of trauma, and known history of osteoporosis, were assessed. Mean cortical bone thickness (CBTavg) on AP radiograph was determined using a previously published method. Cortical thickness on CT scan was measured at 8 and 14 cm proximal to the articular surface of the lateral condyle.
RESULTS: 71 patients (46 females) between 20 and 100 years were included in the study. Cortical thickness determined by CT correlated significantly with CBTavg measurements on AP radiograph (Spearman r = 0.62 to 0.80; p < 0.001). Cortical thickness was inversely correlated with age (Spearman r = - 0.341 to - 0.466; p < 0.001) and significantly associated with trauma impact level and history of osteoporosis (p =  < 0.001). The CT-based values showed a stronger correlation with the clinical parameters than those determined by AP X-ray.
CONCLUSIONS: Our results showed that cortical thickness of the distal femur correlates with clinical parameters of bone quality and is therefore an excellent tool for assessing what surgical care should be provided. Interestingly, our findings indicate that cortical thickness on CT is more strongly correlated with clinical data than AP radiograph measurements.

Distal femoral fractures are commonly treated with lateral straight plates. However, the lateral approach may not always be desirable, and 180°-helical plates may be an alternative.
To investigate the biomechanical competence of 180°-helical plating versus standard straight lateral plating of unstable fractures at the distal femur.
Twelve left artificial femora were instrumented with a 15-hole Locking Compression Plate-Distal Femur, using either 180°-helical plates (group 1) or conventional straight lateral plates (group 2). An unstable distal femoral fracture AO/OTA 33-A3.3 was simulated. All specimens were biomechanically tested under quasi-static and progressively increasing combined cyclic axial and torsional loading in internal rotation until failure.
Initial axial stiffness (N/mm) was significantly higher in group 1 (185.6 ± 50.1) compared to group 2 (56.0 ± 14.4), p < 0.001. Group 1 demonstrated significantly higher initial interfragmentary flexion (°) and significantly lower initial varus/valgus deformation (°) under 500 N static axial compression versus group 2 (2.76 ± 1.02 versus 0.87 ± 0.77 and 4.08 ± 1.49 versus 6.60 ± 0.47), p ≤ 0.005. Shear displacement (mm) under 6 Nm static torsion was significantly higher in group 1 versus group 2 in both internal (1.23 ± 0.28 versus 0.40 ± 0.42) and external (1.21 ± 0.40 versus 0.57 ± 0.33) rotation, p ≤ 0.013. Cycles to failure and failure load (N) (clinical/catastrophic) were significantly higher in group 1 (12,484 ± 2116/13,752 ± 1518 and 1748.4 ± 211.6/1875.2 ± 151.8) compared to group 2 (7853 ± 1262/9727 ± 836 and 1285.3 ± 126.2/1472.7 ± 83.6), p ≤ 0.001.
Although 180°-helical plating using a pre-contoured standard straight lateral plate was associated with higher shear and flexion movements, it demonstrated improved initial axial stability and resistance against varus/valgus deformation compared to straight lateral plating. Moreover, the helical plates were associated with significantly higher endurance to failure. From a biomechanical perspective, 180°-helical plating may be considered as a valuable alternative to standard straight lateral plating of unstable distal femoral fractures.