Polylactic acid polymer interference screws are commonly used in anterior cruciate ligament (ACL) reconstructions, especially in proximal tibia fixation. However, several concerns have been raised, including the acid products during its degradation in vivo. In recent years, biodegradable magnesium (Mg)-based implants have become attractive because of their favourable mechanical properties, which are more similar to those of natural bone when compared with other degradable materials, such as polymers, apart from their alkaline nature during degradation. We developed a pure Mg interference screw for ACL reconstruction. In the present study, 24 fresh cadaver knees were used to compare the mechanical properties of pure Mg interference screws and polylactic acid polymer interference screws for ACL reconstruction via their application on the proximal tibia tested using specific robotics. Results showed that the pure Mg interference screw group showed similar mechanical stability to the polylactic acid polymer interference screw group, implying comparable postoperative fixation effects. As there are no commercially available Mg-based interference screws for ACL reconstruction clinically and the in vivo degradation of pure Mg promotes bone formation, our cadaveric study supports its clinical tests for ACL reconstruction.

Background: Vitamin D deficiency is a common comorbidity in geriatric hip fracture patients. However, there is still an ongoing debate regarding the influence of preoperative Vitamin D status on postoperative mortality in hip fracture patients. Methods: Elderly patients (≥ 60 years) who underwent surgical interventions for unilateral hip fracture from 2015 to 2020 in our center were included. We retrospectively retrieved the demographic data from the electronic medical database. Preoperative serum total 25-hydroxy-Vitamin D was set as the independent variable and patients were classified as the Vitamin D deficiency (< 20ng/mL) and the control groups consequently. Clinical outcomes include all-cause mortality, walking ability, and major postoperative complications in the first postoperative year. Propensity score matching (PSM) was performed in a ratio of 1:1 in the two groups for further comparison. Results: A total of 210 patients were included and 121 patients (57.6%) were diagnosed with Vitamin D deficiency. Patients in the Vitamin D deficiency group were much older and therefore preferred peripheral nerve block, and had significantly higher proportions of females, preoperative dementia, higher ASA grade, and lower baseline serum albumin level. Overall, 79 patients were identified in the Vitamin D deficiency and control groups after PSM, respectively. Patients diagnosed with Vitamin D deficiency showed a significantly higher one-year mortality (21.5% vs 6.3%, P=0.011) and a much lower one-year independent walking rate (67.1% vs.84.8%, P=0.016) after the matching. Regarding the dataset before PSM and after PSM, the AUC for serum Vitamin D for predicting one-year mortality was 0.656 (P=0.006) and 0.695 (P=0.002), respectively. Conclusion: Our retrospective PSM-design study provides new evidence that Vitamin D deficiency was associated with a significantly higher mortality and poor walking ability in the first year after surgical intervention based on southern Chinese populations.

Objective: To investigate the influence of preoperative osteopenia/osteoporosis on periprosthetic bone loss after total hip arthroplasty (THA) and the efficiency of zoledronate (ZOL) treatment in periprosthetic bone preservation.Methods: This multicenter, prospective cohort study was conducted in four centers between April 2015 and October 2017. Patients were assigned to Normal BMD, Osteopenia, and Osteoporosis+ZOL groups. Patients with osteopenia received daily oral calcium (600 mg/d) and vitamin D (0.5 μg/d), while patients in the Osteoporosis+ZOL group received additional ZOL annually (5 mg/year). Periprosthetic bone mineral density (BMD) in seven Gruen zones, radiographic parameters, Harris hip score, EuroQol 5‐Dimensions (EQ‐5D) score, and BMD in hip and spine were measured within 7 days, 3 months, 12 months postoperation and annually thereafter.Results: A total of 266 patients were enrolled, while 81 patients that completed the first year follow‐up were involved in the statistical analysis. The mean follow‐up time was 1.3 years. There were significant decreases of mean BMD in total Gruen zones (−4.55%, P < 0.05) and Gruen zone 1 (−10.22%, P < 0.01) in patients with osteopenia during the first postoperative year. Patients in the Osteoporosis+ZOL group experienced a marked increase in BMD in Gruen zone 1 (+16%) at the first postoperative year, which had a significant difference when compared with the Normal BMD group (P < 0.05) and the Osteopenia Group (P < 0.001). Low preoperative BMD in hip and spine was predictive of bone loss in Gruen zone 1 at 12 months after THA in patients with normal BMD (R² = 0.40, P < 0.05).Conclusions: Patients with osteopenia are prone to higher bone loss in the proximal femur after cementless total hip arthroplasty (THA). ZOL, not solely calcium and vitamin D, could prevent the accelerated periprosthetic bone loss after THA in patients with osteopenia and osteoporosis.

Photocatalytic therapy holds great prospects in high-performance tumor treatment owing to its advantages of noninvasiveness and oxygen nonreliance. However, there is still a lack of ideal photocatalyst materials that respond to near-infrared (NIR) light, especially with organelle-specific features. Here, a mitochondria-biomimetic organic semiconductor photocatalyst was designed for NIR-activatable photocatalytic immunotherapy of recurrent and metastatic tumor. With biomimetic of mitochondrial membrane, a NIR-responsive conjugated polymer YBSe-SS was prepared into biomimetic nano-photocatalysts (Mito-NPs). Upon NIR-light irradiation, the Mito-NPs achieved effective photocatalytic oxidation of reduced nicotinamide adenine dinucleotide and mitochondria dysfunction, benefiting from the mitochondria-targeted performance. Also, relatively high multiphototheranostics were demonstrated by the Mito-NPs. Subsequently, with Mito-NP–regulated mitochondrial function and metabolism, the in vivo experiments proved that the photocatalytic Mito-NPs combined with immune checkpoint therapy achieved photocatalytic immunotherapy for suppressing primary and pulmonary metastasis of osteosarcoma. This work offers a practical paradigm for NIR-activatable organic photocatalytic materials for high-performance tumor therapy.

Purpose: To compare the effects of peripheral nerve block (PNB) and spinal anesthesia (SA) on one-year mortality and walking ability of elderly hip fracture patients after hip arthroplasty. Methods: Patients ≥ 65 years who underwent unilateral hip arthroplasty due to femoral neck fracture, using either PNB or SA from 2014 to 2019, were included. Demographic data, comorbidities, and results of preoperative screening were retrospectively collected. Propensity score matching (PSM) was performed in a ratio of 1:1 for PNB and SA groups. The primary outcomes were 30-day, 90-day, and one-year mortality. Secondary outcomes included walking ability in the first postoperative year, major complications, length of stay, and the cost of hospitalization. Survival analysis was performed using Kaplan–Meier method. Results: Three hundred and sixteen patients were included, of whom 200 received SA and 116 received PNB. Eighty-nine patients in each group were matched after PSM. Patients in the PNB group showed significantly lower risks of death in 30 days (2.2% vs 10.1%, P=0.029) and 90 days (3.4% vs 12.4%, P=0.026) after hip arthroplasty, when compared to the SA group. There was no significant difference in one-year mortality, walking ability, major complications, and length of stay. Higher hospitalization cost was found in the PNB group (53,828.21 CNY vs 59,278.83 CNY, P=0.024). One-year accumulated survival rate was higher in the PNB group without reaching a significant level. Conclusion: PNB was related to lower 30- and 90-day mortality but higher hospitalization cost in elderly hip fracture patients after hip arthroplasty. However, the anesthesia types were not associated with one-year mortality, one-year walking ability, major complications, and length of stay.