To evaluate the causal association between occupational severe cold exposure and the risk of frozen shoulder using Mendelian randomization (MR), and to provide evidence for occupational health interventions.

A two-sample MR design was conducted using exposure data from the UK Biobank and outcome data from the FinnGen database. Genetic variants significantly associated with severe cold exposure were employed as instrumental variables. The inverse variance-weighted method was the primary approach for causal effect estimation, supplemented by sensitivity analyses to ensure robustness.

The results indicated a significant association between occasional severe cold exposure and an increased risk of frozen shoulder [odds ratio (OR) = 2.78, 95% confidence interval (CI) (1.17, 6.57), P=0.020]. No significant associations were observed for rare or frequent severe cold exposure. Sensitivity analyses confirmed the robustness of these findings.

MR study indicates causal evidence linking severe cold exposure to frozen shoulder risk, occasional exposure to severe cold environments may represent a key risk factor for frozen shoulder.

To analyze the efficacy of arthroscopic meniscoplasty and suture fixation in treating discoid lateral meniscus (DLM) injuries, identify risk factors affecting outcomes, and construct a risk prediction model to provide a reference for improving the efficacy and prognosis of DLM injury treatment.

Inclusion criteria: MRI-confirmed DLM injury with symptoms; Watanabe type I or II; unilateral involvement and first-time arthroscopic surgery; complete clinical data without chronic knee diseases. Exclusion criteria: requirement for simultaneous bilateral surgery; history of knee surgery or other knee injuries; concurrent knee infection; surgical contraindications. A single-center, self-controlled cohort study was conducted. A total of 154 patients with DLM injuries who underwent arthroscopic meniscoplasty and suture fixation at the Department of Orthopedics, Renhe Hospital Affiliated to Three Gorges University between January 2020 and January 2024 were enrolled. Lysholm knee joint score scale (LKSS) was used to evaluate efficacy at six months after operation. The patients were divided into two groups based on efficacy: the excellent/good efficacy group (score ≥70) and the poor efficacy group (score <70). Univariation analysis and multivariate logistic regression analysis were performed to identify independent risk factors affecting efficacy, and a predictive model was constructed.

LKSS scores before surgeryand six monthsafter surgery were (67±7) and (90±7) respectively, with a statistically significant difference (t=29.701, P<0.001). The overall excellent efficacy rate at six months after operation was 81.8% (126/154). Univariation analysis and multivariate logistic regression analysis revealed that age [odds ratio (OR) = 1.189], disease duration (OR=1.054), and Outerbridge classification of cartilage injury (OR=1.251) were independent risk factors affecting efficacy ( all P<0.05). A predictive model was constructed based on these independent risk factors, with an area under the receiver operating characteristic (ROC) curve of 0.894 and a critical value of 90, indicating good discriminative ability.

Age, disease duration, and Outerbridge classification of cartilage injury are independent risk factors affecting the clinical efficacy of arthroscopic meniscoplasty and suture fixation for DLM injuries. These risk factors can be used for clinical prognosis risk prediction. High-risk patients (total score >90) with advanced age, prolonged disease duration, and severe cartilage injury may benefit from individualized interventions, treatments, and develop personalized treatment plans and rehabilitation programs.

To investigate the impact of refining the clinical pathway process and management training model for artificial joint replacement on medical efficiency, treatment outcomes, and the competency enhancement of resident physicians.

A total of 258 cases undergoing artificial joint replacementat Sun Yat-sen Memorial Hospital from June 2023 to June 2024 (experimental group) were included and subjected to a refined clinical pathway management model with hierarchical progressive diagnosis and treatment. These cases were compared with 201 cases managed under the traditional clinical pathway model by the same treatment team from June 2022 to May 2023. Inclusion criteria: patients undergoing primary unilateral total hip or knee arthroplasty. Exclusion criteria: revision surgery, multiple joint replacements, active infection, severe osteoporosis, neuromuscular disorders, and incomplete data.Independent samples t test and chi square test were used to compare hospital stay duration, costs, and complication rates between groups. Resident physicians in the experimental group followed the refined clinical pathway for clinical work and training, and their clinical competency improvement was compared with that of the control group.

The experimental group exhibited significantly shorter hospital stays (t=3.061, P<0.05), lower costs (t=5.515, P<0.05), and reduced overall complication rates (χ²=6.592, P<0.05) compared to the control group. The clinical competency of resident physicians under the refined clinical pathway improved significantly (t=-17.174, P<0.001).

Refining the clinical pathway process enhances work efficiency and treatment outcomes, while also promoting the clinical competency of resident physicians.

To explore the therapeutic effect of application of orthosis after HyProCure tarsal sinus screw internal fixation on adolescent patients with flatfoot.

A retrospective study was conducted on 106 patients with flatfoot who were treated in Shangjin Hospital, West China Hospital of Sichuan University from July 2022 to July 2024. Inclusion criteria: age≤18 years old, complete clinical data, no history of surgery, imaging diagnosis of flatfoot (arch disappearance, scaphoid protrusion and heel valgus when standing) and repeated plantar/arch pain. Exclusion criteria: spinal disease, neuromuscular disease, severe osteoarthritis, immune system disease or signs of foot infection. According to the treatment methods, the enrolled patients were divided into operation group (n=52) and combination group (n=54). The operation group accepted HyProCure tarsal sinus screw internal fixation, while the combination group accepted orthosis at three weeks after HyProCure tarsal sinus screw internal fixation. The clinical efficacy as well as lower limb balance status, plantar pressure and imaging measurement indicators before and after treatment were compared between both groups by chi square test and t test.

The total clinical effective rate in the combination group was higher than that in the operation group (χ²=5.075, P<0.05). After treatment, compared with the operation group, the posterior ankle joint-hind foot function score in the combination group was higher (t=5.620, P<0.05). After treatment, the height of the first tarsometatarsal joint and calcaneal inclination angle (Pitch angle) in the combination group were higher than those in the operation group, and the first metatarsal angle (Meary angle) was smaller than that in the operation group (t=3.234, 6.666, 12.041, all P<0.05). The maximum plantar pressure and average plantar pressure in the combination group after treatment were lower than those in the operation group (t=6.568, 6.984, both P<0.05).

Orthosis application at three weeks after HyProCure tarsal sinus screw internal fixation in the treatment of adolescent flatfoot can enhance the clinical efficacy and lower limb balance, and improve the foot structure and plantar pressure of adolescent flatfoot.

To explore the effects of artesunate on wear particle-induced inflammatory osteolysis explored by in vitro and in vivo experiments.

In vitro experiments: healthy mouse embryonic osteoblast precursor cells MC3T3-E1 cells were selected and divided into four groups for culture: blank control group; Ti particle group, where titanium particles were added for osteogenic differentiation culture; artesunate group, where 10 μmol/L artesunate ester was added for osteogenic differentiation culture; combination group, where titanium particles and 10 μmol/L artesunate ester were added simultaneously for osteogenic differentiation culture. Cell activity was determined using the cell counting kit-8 (CCK-8), while apoptosis was analyzed by flow cytometry. In vivo experiments: forty C57BL/6J mice were randomly divided into four groups using a random number table. In the Ti particle group and the Ti + artesunate group, the mice’s scalps were incised and titanium was implanted to establish a mouse skull bone resorption model. In the sham group and the artesunate group, the same surgical procedures were performed without implanting titanium. After establishing the artesunate group and the titanium plus artesunate group, artesunate was administered by gavage at a dose of 50 mg/(kg·d). The mice were executed after two weeks, and hematoxylin-eosin method (HE) staining was used to observe the pathological changes of the skull; enzyme-linked immunosorbent assay (ELISA) was performed to measure the expression levels of inflammatory factors, tumor necrosis factor (TNF) α, interleukin (IL)-1β, and IL -6. Real-time quantitative polymerase chain reaction (RT-PCR) was used to assess the expression of osteogenic differentiation-related genes including alkaline phosphatase (ALP), osteocalcin (OCN), runt-related transcription factor 2 (Runx-2), and collagen type-Ⅰ (COL I). Two weeks after dosing, Micro-CT of the skull was conducted. For comparisons between groups of measurement data, independent samples t test or one-way analysis of variance was used; for multiple comparisons, LSD test was used; and for comparisons between groups of count data, chi square test was employed.

In vitro experiments: CCK8 results showed that at artesunate concentrations ≤10 μmol/L, there was no significant effect on osteoblast proliferation. Titanium particle concentrations≤0.5 mg/ml did not significantly affect the proliferation of MC3T3-E1 cells. Flow cytometry results showed that titanium particles promoted apoptosis in MC3T3-E1 cells (t=57.46, P<0.001); artesunate inhibited the effect of titanium particles (t=19.64, P<0.01). In vivo experiments: HE staining showed that the number of inflammatory cells and the degree of bone destruction in the peri-cranial tissues of the Ti granules group were significantly higher than those of the Ti+artesunate, artesunate, and Sham groups; the inflammatory response was reduced and bone destruction was significantly improved after artesunate intervention. ELISA and PCR results showed that compared to sham group, the Ti particles stimulated a significant increase in the concentration of the three inflammatory factors (t=8.872, 15.6, 18.71, all P<0.05) and a decrease in the mRNA expression of osteogenesis-related genes (t=18.31, 20.47, 23.95, 27.22, all P<0.05). In contrast, compared with the Ti particles group, the Ti + artesunate group showed different degrees of down-regulation of the expression of the three inflammatory factors (t=4.672, 4.805, 3.405, all P<0.01) and increased expression of osteogenesis-related genes (t=12.2, 15.15, 22.02, 16.99, all P<0.05). Micro-CT scans showed that titanium particles led to an increase in bone destruction and induced osteolysisaround the skull, and that the titanium particle-induced osteolysis could be mitigated by the intervention of artesunate.

Artesunate can improve titanium particles induced osteolysis and bone destruction by inhibiting inflammatory factors and up-regulating the function of osteoblasts.

To explore the effect of the combined application of transforming growth factor-β3 (TGF-β3) and stromal cell-derived factor 1α (SDF-1α) with microporous hydrogel on the repair of cartilage injury.

TGF-β3 was transfected into rat bone marrow mesenchymal stem cells (BMSCs) by adenovirus to obtain bone marrow mesenchymal stem cells carrying the TGF-β3 gene (Ad-BMSCs). Genipin crosslinked gelatin microspheres (GMs) were infiltrated into cytokine SDF-1α solution to obtain GMs containing SDF-1α (GMs-S). Then the Ad-BMSCs and BMSCs were suspending in alginate solution, respectively, and mixed with GMs-S, to obtain two groups of hydrogel microspheres (HMs) after calcium in crosslinking reaction as group S+T (containing SDF-1α and TGF-β3) and group S (containing only SDF-1α). Similarly, these two cells alginate solution mixed with GMs respectively to obtain two groups of gelatin microsphere hydrogel as group T (containing TGF-β3) and the blank group.The HMs of each group were cultured in cell incubators under the same conditions,and cell proliferation was detected by cell counting kit-8 assay (CCK-8), the release of SDF-1α and/or TGF-β3 were detected by enzyme-linked immunosorbent assay (ELISA). The gene expression of type I collagen, type Ⅱ collagen, type X collagen and aggrecan (ACAN) were detected by polymerase chain reaction assay (PCR), and expression of sex related Y-box transcription factor 9 (SOX9) protein was detected by western blotting analysis (WB). All the tests in this study were repeated for three times; the quantitative data were described as ±s, t test was used to compare the difference between two groups, and single factor variance analysis was applied for multipe groups comparison. P<0.05 indicated the difference was statistically significant.

CCK-8 data indicated that group S+T had an outstanding ability of cell growth (F=6.904, R²=0.533, P<0.05). SDF-1α (P>0.05) and TGF-β3 (P>0.05) release curves of group S+T and group S were generally consistent. Other results demonstrated that group S+T had greater expression of typeⅡcollagen (comparing the blank group and the group S with the group S+T, P<0.05) and aggrecan (comparing the blank group and the group S with the group S+T, P<0.05) and more synthesized cartilaginous extracellular matrix. Moreover, the WB analysis suggested that the expression of SOX9 protein in group S+T was the highest (each group was compared with the group S+T, P<0.05).

Synergistic effect of SDF-1α and TGF-β3 on BMSCs cultured in microcavitary hydrogel can improve the effect of chondrogenesis.

To elucidate the epigenetic regulatory mechanisms underlying acetabular cartilage dysplasia and chondrocyte degradation in patients with developmental dysplasia of hip (DDH) using single-cell assay for transposase-accessible chromatin using sequencing (scATAC-seq) technology and provide new insights into the cell-specific molecular pathology of DDH.

A total of 64 053 acetabular chondrocytes were collected from six DDH patients (those with a history of hip surgery, infection, or systemic diseases were excluded) and six patients with traumatic femoral neck fracture (TNOF) as controls in Xi’an Honghui Hospital. These cells were analyzed by scATAC-seq to construct a map of genome-wide single-cell chromatin accessibility and reveal cellular heterogeneity. The differences in the proportions of cell types between the two groups were analyzed using Mann-Whitney U test.

Six distinct cell populations in DDH cartilage were identified, such as fibrocartilage chondrocytes (FC), homeostatic chondrocytes (HomC), prehypertrophic chondrocytes (preHTC) and hypertrophic chondrocyte (HTC) as well as regulatory chondrocytes (RegC). The percentage of FC (U=35, P=0.004), HomC (U=36, P=0.002) and preHTC (U=35, P=0.004) were significantly higher in the DDH group than those in the control group. While compared to the control group, the percentage of RegC was remarkably lower in the DDH group (U=1, P=0.004). Disease associated candidate differentially accessible peaks and transcription factors (TF) were revealed, such as HINFP (log₂ FC= 2.84, P=6.31×10⁻⁴) for HomC population and runt related transcription factor 2 (RUNX2) (log₂ FC=1.02, P=1.95×10⁻⁵) for RegC population.

The identified cell types exerted different influences on the development of DDH, which may be driven by corresponding key transcription factor of differential accessible peaks. These findings may provide novel clues for understanding etiology and pathogenesis as well as therapeutic targets of DDH.

To investigate the causal relationship between sulcal morphology (specifically sulcal depth and opening distance) and osteonecrosis through Mendelian randomization analysis, thereby providing new perspectives for research on osteonecrosis pathogenesis and early screening of high-risk populations.

A two-sample Mendelian randomization design was employed, using genetic variants associated with sulcal depth as instrumental variables. Data were derived from large-scale GWAS datasets in the NHGRI-EBI and FinnGen repositories. The primary analysis was conducted using the inverse variance-weighted (IVW) method, with sensitivity analyses to validate the robustness of the findings.

Among 44 sulcal features analyzed, only the sulcal opening depth of the right anterior inferior temporal sulcus was significantly associated with osteonecrosis, showing a negative causal relationship [odds ratio (OR) =0.348, 95% confidence interval (CI) (0.143, 0.847), P=0.020]. Other sulcal features demonstrated no statistically significant associations (all P>0.05).

There might be a causal link between the sulcal depth of the right anterior inferior temporal sulcus and osteonecrosis, which suggests sulcal depth as a potential biomarker for osteonecrosis screening in at-risk population.

To evaluate the clinical efficacy of vertebroplasty combined with anti-osteoporosis drugs in the treatment of osteoporotic vertebral compression fractures in the middle-aged and elderly by meta-analysis.

According to the population, intervention, comparison, outcome and study design (PICOS) principle, the search strategy is formulated and implemented. Cochrane Library PubMed, Excerpta Medica Database (Embase), China National Knowledge Infrastructure (CNKI), Wanfang database, China Science and Technology Journal Database (VIP), Chinese BioMedical Literature Database (CBM) were searched for randomized controlled trials of vertebroplasty combined with anti osteoporotic drugs in the treatment of osteoporotic vertebral compression fractures in middle-aged and elderly patients. The time range of literature search was limited from January 2015 to January 2025, and meta-analysis, review, non randomized controlled trial research and animal experiments were removed. After evaluating the quality of the literature, and extracting the treatment outcome, visual analogue scale (VAS), bone mineral density (BMD), Barthel index score, Oswestry dysfunction index and other outcome indicators, Revman 5.3 and Stata 15.0 software were used for statistical analysis, and fixed effect or random effect models were used to evaluate the heterogeneity.

A total of 11 randomized controlled studies were included in this meta-analysis, including 953 patients, including 481 cases in the experimental group and 472 cases in the control group. The results of meta-analysis showed that the VAS score of vertebroplasty combined with drug therapy for osteoporosis group was lower than that of vertebroplasty alone group [mean difference (MD)=-1.37, 95%confidence interval (CI) (-1.42, -1.32), P<0.05]. BMD was higher in the vertebroplasty combined with drug therapy for osteoporosis group [MD=0.20, 95% CI (0.17, 0.23), P<0.05]. The treatment outcome of vertebroplasty combined with drug therapy for osteoporosis group was better [odds ratio (OR)=2.45, 95% CI (1.41, 4.24), P<0.05]. The Barthel index score was higher in the vertebroplasty combined with drug-therapy-for-osteoporosis group [MD=18.44, 95% CI (16.72, 20.15), P<0.05]. The Oswestry dysfunction index was lower in the vertebroplasty combined with drug therapy for osteoporosis group [MD=-8.38, 95% CI (-9.15, -7.61), P<0.05].

For middle-aged and elderly patients with osteoporotic fractures with vertebral crush injuries, vertebroplasty combined with drug therapy for osteoporosis, compared with vertebroplasty alone, has significantly reduced visual analog score, significantly improved bone mineral density, better treatment outcome, higher Barthel index score, and lower Oswestry dysfunction index. It is suggested that vertebroplasty combined with drug therapy for osteoporosis, should be promoted in the treatment of middle-aged and elderly patients with osteoporotic fractures with vertebral crush injuries.

Articular cartilage has limited self-healing capacity due to the absence of blood vessels and nerves. Stem cell-based tissue engineering offers promising therapies for cartilage repair, but mesenchymal stem cell (MSC) sources are limited, and replicative senescence and decreased chondrogenic differentiation potential occur during in vitro expansion. Decellularized stem cell matrix (DSCM), a bioactive material, enhances MSC proliferation, chondrogenic differentiation, and resistance to replicative senescence and inflammation, making it a promising tool in cartilage tissue engineering. The regenerative efficacy of DSCM in cartilage repair is modulated by variables such as the cell source, fabrication techniques, and modes of application. Notably, its successful application in promoting cartilage regeneration in small animal models underscores its substantial potential for clinical translation. This review highlighted the impact of DSCM deposited by expanded MSCs in vitro on MSC proliferation, chondrogenic differentiation, replicative senescence, and inflammatory response, providing insights into its potential for cartilage repair through stem cell-based tissue engineering.

Hip osteoarthritis is a common degenerative joint disease, and the exact pathogenesis remains incompletely understood. However, substantial evidence suggests that local anatomical abnormalities of the hip joint are risk factors for the development of hip osteoarthritis. Morphological abnormalities such as acetabular dysplasia and femoroacetabular impingement syndrome may play important roles in the onset and progression of hip osteoarthritis. From an imaging perspective, this review summarized the radiographic assessment methods, clinical significance, and recent research advances related to hip morphological abnormalities—including acetabular dysplasia, femoroacetabular impingement, and coxa vara/valga—associated with hip osteoarthritis. The aim is to enhance the understanding of hip osteoarthritis and provide guidance for clinical diagnosis and treatment.

Total knee arthroplasty (TKA) is the main operation for the treatment of knee diseases such as knee osteoarthritis and knee rheumatoid arthritis. It has good effect in reducing the pain of diseased joints and improving joint function. In recent years, with the increasing pursuit of a better life, the amount of TKA surgery is also increasing year by year. However, up to 16%-33% of patients who receive TKA experience chronic pain after surgery, which is one of the main causes of postoperative dissatisfaction. In a large proportion of patients, their surgeons believe that intraoperative evaluation and post-operative radiography indicate that the operation has been successful. More and more surgeons are aware of the importance of non-surgical factors that cause chronic pain after surgery. There are many non-surgical factors that affect chronic pain after surgery. Joint surgeons should determine what kind of patients are likely to have chronic pain after surgery, adjust the status of patients before surgery, and lower the postoperative expectations of patients, so as to improve patient satisfaction and reduce medical disputes. In the event of postoperative chronic pain, revision surgery should only be performed if the cause of the pain has been clearly related to surgical factors, as revision surgery for unexplained pain has been shown to lead to poor outcomes. Through literature review, this article analyzed the non-surgical influencing factors of chronic pain after TKA, aiming to increase the attention of joint surgeons.

Perioperative blood management in total knee arthroplasty (TKA) is a critical measure for ensuring surgical safety and enhancing functional recovery. Recent evidence indicates that while minimally invasive techniques can expedite early postoperative rehabilitation, their effect on perioperative blood loss is limited. The use of tourniquets with restricted duration and low pressure can help reduce complication rates. Combined intravenous and topical administration of tranexamic acid is more effective in reducing blood loss than either route alone. Controlled hypotension and intraoperative blood salvage can significantly decrease the need for allogeneic transfusion and its associated risks. Integrating multiple strategies may further optimize perioperative blood management in TKA, however, individualized protocols still require confirmation by high-quality clinical studies.

To observe and investigate the application of prostheses consisting of titanium alloy long stem and bipolar femoral head with different coatings in hip hemiarthroplasty (HHA) for treatment of geriatric femoral unstable intertrochanteric fractures.

From January 2018 to December 2021, 110 senile patients underwent HHAs for femoral unstable intertrochanteric fractures (59 patients had severe osteoporosis with T value under 2.5) in XD Group Hospital. A retrospective analysis was performed on the perioperative and follow-up informations of these patients. The femoral stems for implantation were titanium alloy stems, and 64 and 46 HHAs used stems coated with hydroxyapatite and with micro-arc oxidized TiO₂, respectively. The overall comorbidities during hospitalization and changes in Harris hip scores (HHS) were compared at three, six, 12, 24 months after surgery by t test and variance analysis. Radiographic features were recorded and analyzed, including osteolysis, prosthesis subsidence, acetabular erosion, cortical porosis, heterotopic ossification, and leg length discrepancy, as well as records of stem revisions.

All the patients were followed up for 44 (35, 55) months, and among them 89 patients had postoperative radiographs available for analysis. HHS scores after operation showed no statistically significant differences in inter-group effect (F=0.634, P>0.05, ∂η²=0.006) or interactive effect (F=0.338, P>0.05, ∂η²=0.003), while the difference in time effect was statistically significant (F=656.51, P<0.001, ∂η²=0.859). There was observed a relatively low occurrence of negative features according to radiographic analysis. No prosthesis loosening, osteolysis, or leg length discrepancy was found. One case encountered prosthesis subsidence (1.1%), two (2.3%), one (1.1%), and three (3.4%) hips encountered acetabular erosion, heterotopic ossification, and cortical porosis respectively; three hips (3.4%) received stem revision owing to periprosthetic fractures.

The application of titanium alloy femoral long stems can achieve satisfactory utility in HHA treatment of geriatric femoral unstable intertrochanteric fractures. Due to the merits such as shorter surgery time compared to cemented-type stems, titanium alloy femoral stems have more promising applicative potential.

To determine the clinical effect after side-to-side repair for radial posterior lateral meniscus root tears (PLMRTs) under arthroscope.

A retrospective analysis was conducted on the data of 27 patients who suffered from posterior root radiating tears of the lateral meniscus due to trauma and underwent arthroscopic lateral-lateral suturing at the Sports Medicine Center of Second Affiliated Hospital Inner Mongolia Medical University from January 2019 to January 2021.The preoperative and last follow-up International Knee Documentation Committee (IKDC) subjective scores, Lysholm and Tegner scores, and complications were recorded. Paired sample t-tests were used to analyze the differences in scores before and after surgery.

All 27 patients met the inclusion criteria and were followed up for an average of (16±4) months. There were 19 males and 8 females, with an average age of (26±8) years, and the average time from injury to surgery was (15±11) days. During the follow-up period, no patient experienced re-tear of the meniscus, joint space tenderness, or positive McMurray test. The IKDC score (93.1±2.3), Lysholm score (96.2±3.0), and Tegner score (5.9±0.6) at the last follow-up were significantly higher than those before surgery (43.4±6.3), (55.3±4.6), and (2.5±0.7), with statistically significant differences (t=40.83, 45.96, and 26.30, respectively; P=0.01).

Arthroscopic lateral-lateral repair for PLMRTs can significantly improve the subjective and objective functions of patients, and the clinical efficacy is remarkable. The passive voice in the past tense is used for expression.

To explore the application effect of time-selective acupoint application based on the midnight-noon ebb-flow theory in patients with postoperative constipation following knee arthroplasty.

Seventy-two patients who developed constipation after knee arthroplasty were divided into two groups based on admission order, 36 patients in each.The experimental group underwent time-selective acupoint application aligned with the midnight-noon ebb-flow theory, alongside routine care.The control group received non-time-selective acupoint application in addition to routine care.Time to first postoperative defecation, defecation duration, defecation intervals, overall treatment outcome, and PAC-QOL scores were compared between the two groups by t test and chi square test.

The experimental group experienced shorter times to first postoperative defecation, shorter defecation durations,and reduced defecation intervals compared to the control group (t=7.139, 4.971, 1.937, all P<0.001). The constipation improvement was also markedly better in the experimental group. Tthe experimental group showed higher total marked effective and total effective rates compared to the control group (χ²=7.35, 7.35, all P<0.05). Both groups exhibited improved PAC-QOL scores after intervention compared to the scores before intervention (t=7.448, 5.682, all P<0.001); the PAC-QOL score of experimental group was superior to the control group (t=2.125, P<0.05).

Time-selective acupoint application based on the midnight-noon ebb-flow theory demonstrates good efficacy in alleviating constipation in patients after knee arthroplasty.