Background: It is still unclear whether reverse total shoulder arthroplasty (RTSA) has advantages over traditional hemiarthroplasty (HA) and anatomic total shoulder arthroplasty (ATSA) in the treatment of complex shoulder joint diseases. Therefore, this study aims to evaluate the clinical effectiveness of RTSA in the treatment of complex shoulder joint diseases and further determine whether it is necessary to expand the indications of RTSA.

Method: We conducted a systematic search of studies published between January 1, 2012 and May 31, 2023 in PubMed, Embase, and Cochrane databases. The experimental group included patients who underwent primary reverse total shoulder arthroplasty (RTSA), while the control group consisted of patients who underwent primary hemiarthroplasty (HA) or anatomic total shoulder arthroplasty (ATSA). The minimum follow-up period was 1 year, and a random-effects model was utilized for data synthesis.

Results: A total of 45 studies were included in the meta-analysis. Compare to HA, RTSA showed significant advantages in postoperative ASES scores (p = 0.004), forward flexion (p < 0.0001), and abduction (p < 0.0001). Compare to ATSA, RTSA showed significantly lower postoperative Constant scores (p = 0.004), ASES scores (p = 0.001), SST scores (p < 0.0001), forward flexion (p < 0.0001), abduction (p = 0.011), internal rotation (p < 0.0001), and external rotation (p < 0.0001). Further meta regression analysis was conducted, considering factors such as region, age, gender ratio, and follow-up time, excluding the influence of relevant factors. Overall, RTSA did not demonstrate advantages in postoperative functional scores and range of motion. In terms of complication and revision rates, RTSA had lower rates compared to HA and ATSA, except for the complication rate, where there was no significant difference between RTSA and ATSA (p = 0.521), but statistically significant differences were observed in other measures.

Conclusion: RTSA demonstrates better clinical efficacy compared to HA but is inferior to ATSA. It can be considered for expanding treatment options for elderly patients with 3 or 4-part proximal humeral fractures, but it is not suitable for treating end-stage shoulder arthritis and humeral head necrosis. Overall, the decision to use RTSA should be carefully evaluated based on the extent of the patient’s rotator cuff injury.

Anterior cruciate ligament (ACL) injuries are the most common knee joint injuries related to sports activities in clinical practice. For treating ACL injuries, anatomical reconstruction surgery is often the preferred method. The over-the-top (OTT) technique is a surgical approach that eliminates the need for creating a femoral tunnel. According to the existing literature, the OTT technique offers distinct advantages, particularly for skeletally immature individuals and in revision cases. Currently, femoral tunnel failure is the most common cause of ACL reconstruction failure, which can lead to less than optimal postoperative performance of the ACL and a higher likelihood of needing a revision. Additionally, mistakes in the placement of the femoral tunnel and the subsequent risk of tunnel enlargement can increase the complexity of revision procedures, ultimately reducing the long-term clinical effectiveness for patients. In contrast, the OTT technique has shown excellent biomechanical performance, avoids the need for bone tunnels, is economically practical, and has been proven to provide satisfactory therapeutic outcomes both in the short and long term, especially for skeletally immature individuals and in revision cases. The OTT technique is deemed a safe and effective surgical method for treating ACL injuries. In summary, the OTT technique has unique benefits for skeletally immature individuals and in revision cases, making it a viable option worth considering.

Level of evidence V.

Objective: The rehabilitation methods after total knee arthroplasty (TKA) can affect the recovery of complications and joint function, and the selection and comparison of rehabilitation methods after TKA still need further research.

Methods: A comprehensive search of five databases and two clinical trial registration platforms was conducted from inception through March 31, 2024, and conducted to identify eligible randomized controlled trials (RCTs). We extracted the required data according to the Cochrane Handbook for Systematic Reviews of Interventions. Finally, 32 trials involving 2292 patients were included, the mean age of the enrolled patients was ∼69.10 years, the sex ratio of males was (31.6%), and the longest follow-up time was 2 years. And we have summarized nine rehabilitation intervention measures: conventional physical therapy (CPT), cryotherapy, thermal therapy (TT), acupuncture, hydrotherapy, neuromuscular training (NT), electrotherapy, continuous passive motion (CPM), continuous active motion (CAM). And use the range of motion (ROM), visual analog scale (VAS), Western Ontario and McMaster Universities osteoarthritis index (WOMAC) as the outcome measure to evaluate the effectiveness of various interventions. A Bayesian network meta-analysis (NMA) was carried out for calculating standardized mean difference (SMD) and the surface under cumulative ranking curve (SUCRA) of improvement of knee joint function after TKA by different rehabilitation methods.

Result: After treatment, the ROM results showed that cryotherapy, electrotherapy, and NT had better therapeutic effects. Among them, cryotherapy (WMD = 10.3, 95% CI 1.63–18.2) had a significant therapeutic effect. In terms of VAS, NT and TT showed good therapeutic effects. Among them, NT had a more significant therapeutic effect, while CAM had less effect. After treatment, in terms of WOMAC, TT, hydrotherapy, cryotherapy, and NT had better therapeutic effects. TT had the best therapeutic effect, while Hydrotherapy and Cryotherapy also had certain advantages.

Conclusion: NT, TT, cryotherapy, hydrotherapy, and electrotherapy rehabilitation therapies have good therapeutic effects for TKA patients compared with other interventions. Among them, NT may be the best postoperative rehabilitation therapy.

Objective: Femoral neck fractures in the elderly are a global health issue, with the choice between cemented and uncemented hemiarthroplasty remaining a topic of debate. This systematic review and meta-analysis aims to compare the effects of the two surgical options on health-related quality of life (HRQoL), mortality, and functional outcomes.

Methods: We searched PubMed, Embase, and Cochrane databases for randomized controlled trials (RCTs) comparing cemented with uncemented hemiarthroplasty in patients aged 50 years and older with femoral neck fractures. The primary outcome of interest was HRQoL as measured by the European Quality of Life 5-Dimension Questionnaire (EQ-5D) score. Secondary outcomes included mortality, surgical, general, and local complications.

Results: We included 20 RCTs with a total of 3680 patients with femoral neck fractures, of whom 1871 (50.5%) underwent cemented and 1809 (49.5%) uncemented hemiarthroplasty. The follow-up ranged from 1 to 6 years. The early (after 3–4 months) EQ-5D utility score (MD 0.07; 95% CI 0.03–0.12; p = 0.003; I ² = 22%) and the 12-month EQ-5D utility score (MD 0.08; 95% CI 0.00–0.16; p = 0.04; I ² = 67%) suggested an improved HRQoL in the cemented hemiarthroplasty group. The outcomes of 1-year mortality, requirement for additional surgeries, surgery duration, risk of pulmonary embolism, pressure sores or ulcers, intraoperative fractures, and periprosthetic or postoperative fractures demonstrated significant differences between the two groups.

Conclusions: The use of cemented hemiarthroplasty in patients with femoral neck fractures presented better results when compared to uncemented hemiarthroplasty in terms of HRQoL during the first year after surgery and greater mortality reduction at 1 year follow-up and reduced the need for further surgery. Therefore, the use of cemented hemiarthroplasty may be preferred for the treatment of femoral neck fractures in elderly patients.

Objective: Patients with osteoporotic vertebral compression fractures (OVCF) treated with vertebroplasty (PVP) are experiencing an increasing number of problems such as pain recurrence, mainly due to recompression fractures of the operated vertebral body within a certain period of time after the operation, which is closely related to the distribution of intraoperative bone cement. The aim of this study is to investigate the effect of different spacing distributions between the upper boundary of the cement and the upper endplate of the operated vertebra on the biomechanics of the operated vertebra after percutaneous vertebroplasty for OVCF using finite element analysis (FEA).

Methods: One patient with L1 vertebral body OVCF was selected, and computed tomography (CT) of the thoracolumbar segment was performed. The CT data were extracted to establish an FEA model of the T12–L2 vertebral bodies. Bone cement was injected into the L1 vertebral body. Based on the spacing between the upper boundary of the bone cement and the vertebral body’s upper endplates, the model vertebrae were divided into 0, 2, 4, and 6 mm spacing groups, and the human body’s upright, flexion–extension, lateral flexion, and rotational positions were simulated. The biomechanical effects of different spacing distributions on the postoperative L1 vertebral body and the injected bone cement were evaluated.

Results: In this paper, we found that the Von Mises stress of the L1 vertebrae was the smallest when the spacing between the upper boundary of the bone cement and the vertebral body’s upper endplates was 0 mm. The larger the spacing in a certain range between the upper boundary of the bone cement and the vertebral body’s upper endplates, the greater the Von Mises stress of the L1 vertebrae. However, in the stress comparison of the injected bone cement, the Von Mises stress of the bone cement was greatest when the spacing between the upper boundary of the bone cement and the upper endplate of the vertebral body was 0 mm; the larger the spacing, the smaller the Von Mises stress.

Conclusion: When the contact spacing between the upper boundary of the bone cement and the upper endplate of the vertebral body is 0 mm, it can effectively eliminate and transfer the pressure caused by the load, thus reducing the stress on the cancellous bone and further reducing the risk of vertebral refracture after surgery.

Object: With the development of new technologies, the surgical algorithm for ossification of posterior longitudinal ligament (OPLL) in the cervical spine also needs to be updated. The aim of this study is to elucidate a new surgical classification algorithm to guide the choice of surgical approaches for cervical OPLL based on its location and extent. In this algorithm, anterior controllable antedisplacement and fusion (ACAF) will be used as a new surgical option.

Methods: This is a single-centered, retrospective, cohort study utilizing a novel algorithm based on the following three criteria: (1) the positional relationship between ossification and uncinate process (UP), (2) the K-line, and (3) the ossification segment for surgical decision-making. Patients diagnosed with cervical OPLL who received surgical intervention guided by the algorithm were included. Patient demographics, Japanese Orthopedic Association (JOA) scores, surgical time, imaging data before and 2 years after surgery, and the occurrence of complications were extracted from the database. Paired t-test was used for intragroup comparison, and one-way ANOVA test was used for the intergroup analyses.

Results: Based on this novel algorithm, 15 patients with Type I, 8 patients with Type II a, 2 patients with Type II b1, 5 patients with Type II b2 were included. The decision-making for the surgical techniques used in each patient followed the recommendation of the novel algorithm. The postoperative JOA scores of all types of patients improved significantly (p < 0.05), and the invasion rates of vertebral canal had also been significantly reduced (p < 0.05). In terms of restoring cervical curvature, patients with Type I (receiving ACAF) and Type II b2 (receiving laminectomy with instrumented fusion) benefited more from surgery (p < 0.05).

Conclusion: A new algorithm guiding the choice of surgical approach for cervical OPLL was validated in a series of 30 patients. Through this analysis, we obtained on their clinical outcomes and complications. ACAF surgery is an ideal choice for Type I patients, with ossification located between UPs, while for patients with ossification exceeding UPs, it is better to perform anterior cervical corpectomy and fusion or posterior surgery.

Objective: Osteoporosis is a crucial risk factor for screw loosening. Our studies indicate that the bone mineral density (BMD) in the screw trajectory is a better predictor of screw loosening than the BMD of the lumbar spine or the screw insertion position. Research has shown that anchorage on the screw tip is the most significant factor for screw anchorage ability, while others argue that decreased bony quality in the pedicle poses a significant risk for screw loosening. This study aimed to determine whether the bony quality of the screw tip, pedicle, or screw-anchored vertebral body plays the most significant role in screw anchorage ability.

Methods: A total of 73 patients who underwent single–segment bilateral pedicle screw fixation, along with posterior and transforaminal lumbar interbody fusion (PLIF and TLIF), from March 2019 to September 2020 were included in this retrospective study. The Hounsfield unit (HU) value of the fixed vertebral bodies, the entire screw trajectory, screw tip, screw–anchoraged vertebral body, and pedicles were measured separately. Data from patients with and without screw loosening were compared, and regression analyses were conducted to identify independent risk factors. Additionally, the area under the curve (AUC) values were computed to assess the predictive performance of different parameters. Furthermore, fixation strength was calculated in numerical models with varying bony densities in different regions.

Results: HU values were found to be significantly lower in the loosening group across most measuring methods (HU values in the pedicle, 148.79 ± 97.04, 33.06 ± 34.82, p < 0.001). Specifically, the AUC of screw loosening prediction was notably higher when using HU values of the pedicle compared to other methods (AUC in the pedicle > 0.9 and in the screw insertion position > 0.7). Additionally, computational results for fixation strength revealed a clear decline in screw anchorage ability in models with poor BMD in the pedicle region.

Conclusions: Pedicle bone quality plays a more significant role in screw anchorage ability than that in other regions. The innovation of bony augmentation strategies should pay more attention to this region to optimize the screw anchorage ability effectively.

Background: Anterior controllable antedisplacement and fusion (ACAF) is an emerging surgical approach for treating cervical ossification of the posterior longitudinal ligament (C-OPLL), yet there is limited data on its long-term efficacy and safety. The present study aimed to analyze the short- and long-term postoperative clinical and radiological outcomes and perioperative complications of ACAF for patients with C-OPLL.

Methods: This was a single-center, retrospective, cohort study, with the mean duration of follow-up of at least 24 months. A total of 111 patients with C-OPLL in our institution from June 2017 to June 2019 were assessed preoperatively and at 3 days, 3, 6, 12, and 24 months postoperatively. The primary outcome was the recovery of neurological function, measured with the Japanese Orthopedic Association (JOA) score. The secondary outcomes included pain, Cobb angle, spinal canal invasion rate, and surgery-related complications.

Results: The postoperative JOA score at each follow-up was significantly better than the preoperative JOA score, regardless of preoperative spinal canal invasion rate, K-line, and segment length. The visual analog scale (VAS) score also decreased dramatically 3 days after surgery and was maintained at a low level throughout the follow-up period. Improvements in Cobb angle and invasion rate were observed right after the operation and were maintained for 2 years thereafter.

Conclusions: ACAF could achieve satisfactory recovery of neurological function in C-OPLL patients during a follow-up of 24 months, regardless of preoperative spinal canal invasion rate, preoperative K-line, or surgical segment length.

Objective: The influence of the graft sagittal inclination angle (SIA) on knee stability, biomechanics, and graft maturity has been elucidated. However, no study has comprehensively described the effects of SIA on the aforementioned postoperative prognostic indicators. So, we aimed to determine whether the sagittal inclination angle (SIA) of a graft is associated with postoperative graft maturity, joint stability, and joint function after anterior cruciate ligament (ACL) reconstruction.

Methods: Patients who had undergone ACL reconstruction between April 2019 and February 2022 and those with intact ACL were eligible. Using magnetic resonance imaging, graft maturity was evaluated as the mean signal-to-noise quotient (SNQ) measured in three regions. Anterior tibial translation (ATT) was used to evaluate knee stability. Correlation analysis was conducted for the SIA, ATT, and clinical outcome scores. Multivariate stepwise regression analysis was used on the SIA and potential risk factors to determine their association with the graft SNQ. The SIA threshold of knee instability was calculated by receiver-operating characteristic curves.

Results: Sixty-three postoperative patients were enrolled. The SIA was significantly negatively associated with graft SNQ value. A multivariate stepwise regression analysis showed that SIA and body mass index were significant influencing factors associated with the graft SNQ. Correlations between the SIA and medial and lateral ATT were statistically significant. A larger SIA resulted in a decreased probability of medial and lateral ATT ≥ 5 mm. The SIA threshold of an increased risk of lateral ATT ≥ 5 mm was < 44.4°. A positive correlation was observed between SIA and subjective symptom subscales in the KOOS.

Conclusions: A low SIA is not conducive to graft maturation after ACL reconstruction. A larger graft SIA was correlated with better postoperative knee stability. However, the effect of the SIA on joint function was only significant in terms of symptoms. Therefore, these new findings provide new ideas for preoperative assessment and intraoperative determination of the ideal graft inclination.

Objectives: To minimize the risk of V3 segment of vertebral artery (VA) injury in the atlantoaxial dislocation (AAD) patients with C1 pedicle height less than 4.0 mm and provide a strong toggle force in irreducible AAD and revision surgery. We evaluated the feasibility of C1 “Zero Angle” screw (C1ZAS) and safe entry point with “in–out–in” technique as an alternative option for C1 pedicle screw (PS) in cases with AAD.

Methods: Sixty-one patients with AAD or atlantoaxial instability (AAI) (45 male and 16 female) who underwent cervical computed tomography and magnetic resonance imaging scans in our center between January 1, 2022 and December 31, 2023 were retrospectively reviewed. Measurements were made around the ideal trajectory and entry point of C1ZAS using computerized tomography (CT) and magnetic resonance imaging (MRI) in 61 patients. Radiographic measurements included (A) the distance from the recess to the transverse foramen (RTF); (B) the tricortical screw zone (TSZ); (C) the lateral mass height along the C1ZAS trajectory (LMH); (D) the screw length of C1ZAS (ZSL); (E) the screw length of C1 PS (PSL); (F) the distances from the recess to the dura (RD); (G) the distance from the recess to the spinal cord (RSC); (H) the distance from the inner of lateral mass to the spinal cord (ILMSC). During the period of January 1, 2022 to December 31, 2023, C1ZAS placement with “in–out–in” technique was used as an alternative option for C1 PS in 8 patients with AAD and unilateral/bilateral narrow C1 pedicles.

Results: The average RTF, TSZ, LMH, ZSL, RD, RSC, and ILMSC were 7.71, 6.14, 8.32, 33.23, 4.68, 10.02, and 2.91 mm respectively. The entry point of the C1ZAS was defined as the projection point of the inner of the recess to the posterior arch and the trajectory should be angled cephalad by 8.7° and medially by 0°. The 61 patients (122 sides) with AAD or AAI were classified into three groups: the low-risk (76 sides, 62%), the intermedial-risk (18 sides, 15%), and the high-risk (28 sides, 23%) groups. Satisfactory C1ZAS placement and atlantoaxial reduction were achieved in all eight patients with AAD and unilateral/bilateral narrow C1 pedicles. No instance of C1ZAS placement-related VA injury or dural laceration was observed.

Conclusions: When the placement of C1 PS is not feasible in patients with AAD and unilateral/bilateral narrow C1 pedicles, C1ZAS placement with “in–out–in” technique can be considered an effective alternative option, providing tricortical or quadricortical purchase for rigid fixation of the atlas.

Objectives: Cage subsidence is a common complication of oblique lumbar interbody fusion (OLIF), particularly in elderly patients with osteoporosis or osteopenia. While bilateral pedicle screw fixation (BPS) is effective in reducing subsidence, it is associated with longer operative times, increased blood loss, and greater tissue trauma. In contrast, anterolateral fixation (AF) is less invasive but linked to higher subsidence rates. Ensuring both minimal invasiveness and adequate stability in OLIF-assisted fixation remains a significant challenge. This study aimed to evaluate the efficacy of combining AF with cement augmentation (AF + CA) in reducing cage subsidence and improving clinical outcomes compared with AF and BPS.

Methods: A retrospective analysis was conducted on 138 elderly patients with degenerative lumbar diseases treated with OLIF. Patients were divided into three groups: AF + CA (32 patients), AF (32 patients), and BPS (74 patients). Clinical and radiographic outcomes were compared among the groups, and logistic regression analyses were performed to identify risk factors for cage subsidence after OLIF.

Results: At 1 year postoperatively, the disc height of the AF + CA group was significantly greater than that of the AF group. The cage subsidence rate in the AF + CA group was 24.3%, significantly lower than that in the AF group (48.8%, p < 0.05) and comparable to the BPS group (30.4%). Survivorship curve analysis showed better outcomes in reducing cage subsidence in the AF + CA group compared with the AF group, with no significant difference between the AF + CA and BPS groups. Compared with the AF + CA and BPS groups, the AF group had significantly higher grades and severity of cage subsidence. Fusion rates at 1 year were 91.9% in the AF + CA group, 90.2% in the AF group, and 95.1% in the BPS group, with no significant differences. The AF + CA group had significantly shorter operative times, less intraoperative blood loss, lower VAS scores at 3 days and 1 year postoperatively, and lower ODI scores at 3 days and 3 months compared with the BPS group. Multivariate regression analysis revealed that AF was a significant risk factor for cage subsidence, with an odds ratio of 3.399 compared with AF + CA.

Conclusions: AF + CA effectively reduces cage subsidence in OLIF surgeries, offering results comparable to BPS while providing advantages such as shorter surgical time, reduced blood loss, and improved early postoperative outcomes. AF + CA is a viable alternative, especially for elderly patients with comorbidities who may not tolerate the longer operative durations or greater blood loss associated with BPS.

Objective: The relationship between cervical disc degeneration and bone quality of adjacent vertebral body remains controversial. This study aims to investigate the relationship between cervical disc degeneration and bone quality of the adjacent vertebral body and sub-endplate bone with a new MRI-based bone quality score in patients over 50 years with cervical spondylosis.

Methods: We retrospectively reviewed 479 cervical disc segments from 131 patients. Disc degeneration at levels C3/C4–C6/C7 was graded using T2-weighted MRI. Vertebral body quality (VBQ) score and sub-endplate bone quality (EBQ) score from C3 to C7 were computed from T1-weighted MRI images. Additionally, bone mineral density (BMD) of the cervical vertebrae was measured in 52 patients using a novel phantom-less quantitative computed tomography (PL-QCT) system. The correlation between bone quality score and Pfirrmann grade was analyzed and risk factors for VBQ and EBQ were further evaluated.

Results: Significant differences were found in cranial VBQ among different Pfirrmann grades, with a score of 2.55 ± 0.54 for Grade 5 discs, which was lower compared to Grades 4 (2.70 ± 0.56) (p < 0.05) and 3 (2.81 ± 0.58) (p < 0.01). Caudal VBQ for Grade 5 discs (2.43 ± 0.52) was also significantly lower than for Grade 3 discs (2.66 ± 0.54) (p < 0.01). EBQ scores decreased with increasing Pfirrmann grades. Negative correlations were observed between both cranial and caudal VBQ and EBQ scores and Pfirrmann grades. Grades 4 and 5 discs were identified as independent risk factors for decreased caudal VBQ and EBQ, whereas only Grade 5 was a significant risk factor for decreased cranial EBQ. Additionally, a moderate correlation (0.4 < R < 0.6, p < 0.05) was noted between vertebral body BMD and VBQ at each cervical level.

Conclusion: In individuals over 50 years with cervical spondylosis, the severity of disc degeneration was closely correlated with denser bone quality in both the caudal vertebral body and sub-endplate, as measured by VBQ and EBQ scores. These findings suggest that worsening disc degeneration is associated with increased bone density in specific areas of the cervical spine.

Purpose: Following failed internal fixation of intertrochanteric fractures (FIF-ITF), the decision to use a long-stem or standard-stem femoral implant in hip arthroplasty is still debated. This study aimed to explore how the healing status of fractures after FIF-ITF failure affects the choice of femoral stem and clinical outcomes.

Methods: Our retrospective cohort study reviewed 105 cases of patients with FIF-ITF who underwent hip arthroplasty at three tertiary Grade A hospitals between December 2012 and December 2022. We compared the clinical outcomes between patients with healed and unhealed fractures, focusing on the selection of femoral stems in relation to proximal medial support and the healing status of the greater trochanter. The primary outcomes measured were functional results, operative time, blood loss, and incidence of complications. A subgroup analysis was conducted to further evaluate the influence of the proximal medial buttress and greater trochanteric healing on femoral stem selection. Statistical analysis included binary and ordinal logistic regression to identify factors influencing the choice of femoral stems. Additionally, a decision tree model was developed to visually represent and explore the relationship between fracture healing status and the selection of femoral components.

Results: The study included 38 patients with healed fractures and 67 patients with unhealed fractures. Patients in the healed group predominantly chose standard stems and experienced better functional outcomes (p < 0.001, p = 0.002). In contrast, the unhealed group preferred long stems, resulting in longer surgical durations and increased blood loss (p = 0.008, p < 0.001). Binary logistic regression analysis revealed that nonunion of the proximal femoral medial buttress was an independent risk factor for long stems (p < 0.0001, OR = 10.402).

Conclusion: The selection of femoral prostheses following FIF-ITF is influenced by the fracture healing status, particularly the presence of proximal femoral medial buttress. The decision tree model suggested that long-stem prostheses are more appropriate when there is inadequate fracture healing and the proximal femoral medial buttress is absent.

Objectives: Lumbar disc herniation (LDH) is a common degenerative spinal disease in clinical practice. This study aims to investigate the impact of Modic changes (MCs) on postoperative recovery and disease recurrence following percutaneous endoscopic lumbar disc discectomy (PELD), providing important insights for improving the management of chronic low back pain. This study investigates the 1-year progression rate of MCs after PELD and their impact on surgical outcomes and recurrence.

Methods: This retrospective cohort study analyzed data from 419 patients with single-segment lumbar disc herniation who underwent PELD between January 2019 and December 2022. Lumbar MRI assessed preoperative and postoperative MCs. Pain levels and surgical outcomes were evaluated using the visual analog scale, Oswestry Disability Index, and Macnab criteria. Univariate analysis explored the relationship between postoperative MCs and pain, while subgroups investigated the associations between postoperative efficacy, recurrence, and MCs type and area.

Results: One-year follow-up revealed that the probability of MCs postsurgery was 24.8%. Patients with postoperative MCs had significantly lower pain scores compared with the control group (p < 0.05). Univariate analysis indicated that the type and area of postoperative MCs were risk factors for poor outcomes in PELD patients (p < 0.05). During the 1-year follow-up, recurrence rates in the no-MCs and MCs groups were 3.8% and 9.6%, respectively (p < 0.05). Univariate analysis concluded that the area of postoperative MCs was a risk factor for PELD recurrence.

Conclusion: The postoperative MCs, as a risk factor, may have a detrimental effect on the surgical efficacy and short-term recurrence of LDH following PELD based on a large sample. Furthermore, the harmful effect is affected by the area and type of the postoperative MCs.

Objective: Ilizarov technology is highly effective in addressing complex orthopedic challenges. This study aims to describe our experience with distraction osteogenesis in managing bone tumors in the lower extremity, focusing on composite bone defects and associated complications.

Methods: A retrospective clinical study was conducted to analyze patients with primary bone tumors who underwent distraction osteogenesis using the Ilizarov method from 2010 to 2020. Some young children received epiphyseal distraction and bone transport as part of their sarcoma surgical treatment. Additionally, external fixation, bone transport, or limb lengthening were employed to address complex postoperative complications associated with bone tumors. The clinical outcomes assessed included the patient’s general information, the location of bone defects, the length of bone repair, the status of bone healing, and limb function.

Results: Eleven patients were followed up for an average of 66 months (range, 24–132 months). The average length of repaired bone defects was 13 cm (range, 2.5–32 cm). The cohort comprised three females and eight males, with ages at presentation ranging from 6 to 42 years (mean, 18 years). The sites of involvement included the distal femur (n = 4), femoral diaphysis (n = 3), proximal tibia (n = 2), and the distal tibia (n = 2). Nine patients were diagnosed with osteosarcoma, while one presented with Ewing’s sarcoma and another with a giant cell tumor of bone. Three young children were successfully treated with epiphyseal stretching; however, one patient experienced treatment failure. Additionally, seven patients underwent external fixation to address complex postoperative complications, including infection, bone defects, and limb shortening. At the last follow-up, with the exception of one failure, the average Musculoskeletal Tumor Society (MSTS) limb function scores for the remaining 10 patients were 25 (range, 21–30). Three months post-fixator removal, the Asociación Latinoamericana de Oncología (ASAMI) bone score was rated as excellent in 63.6% (7/11) of patients, whereas the ASAMI function score was excellent in 36.4% (4/11) and good in 54.5% (6/11) of cases.

Conclusion: The Ilizarov method demonstrates some clinical value in the resection and reconstruction of bone tumors, as well as in the management of postoperative complications associated with such tumors.

Objective: Central cord syndrome (CCS) is an incomplete spinal cord injury (SCI) causing severe motor weakness, and timely decompression via surgical intervention facilitates better recovery. Anterior controllable antedisplacement and fusion (ACAF) is a novel decompression technique and achieved satisfactory outcomes in treating cervical degenerated diseases. However, the clinical effects of ACAF on CCS remains unknown. This present study aimed to investigate the clinical outcomes of ACAF for cervical stenosis patients with CCS due to hyperextension injury.

Methods: This is a retrospective study, and patients who underwent ACAF due to CCS in our institution from July 2021 to December 2022 were enrolled based on the inclusion and exclusion criteria. All patients underwent x-ray, computed tomography (CT), and magnetic resonance imaging (MRI) before and after surgery. The duration of follow-up was at least 12 months. The radiological parameters included associated pathologies, prevertebral hyperintensity (HI), intramedullary signal intensity (ISI), and Torg–Pavlov ratio (TPR). The cervical stability was also evaluated. Neurological function was assessed using the American Spinal Injury Association (ASIA) grading system and Japanese Orthopaedic Association (JOA) score. The Mann–Whitney U test was used to compare the clinical outcomes preoperatively and postoperatively.

Results: Finally, 13 patients (7 male and 6 female) with the minimum of 12-month follow-up were finally enrolled in this study, with the mean age of 56.6 ± 12.5 years (range, 39–74 years). There were eight patients suffered CCS due to fall, three due to vehicle accident, and two due to diving injuries. The average delay from injury to surgery was 2.23 days (range, 1–4 days), and the mean duration of follow-up was 16.1 ± 3.5 months. In terms of prevertebral HI and ISI, C4–C6 were the most affected region. In addition, 76.9% (10 of 13) patients were observed to have cervical stenosis indicated by TPR. Associated pathologies were herniated nucleus pulposus (HNP) in five patients, OPLL in three cases, and HNP-osteophyte complexes (HNP-OC) in six patients. At the final follow-up, 13 patients were improved to E. The mean JOA score improved to 15.4 ± 1.0, with the recovery rate of 77.0% ± 12.0%. Two patients experienced postoperative dysphagia, two patients had hoarseness, and one patient suffered postoperative hematoma.

Conclusions: ACAF can be a good option for treating CCS patients due to hyperextension injury with underlying cervical spondylosis and stenosis.

Objectives: Currently, unilateral biportal endoscopic (UBE) and uniportal full-endoscopic (UFE) techniques for the treatment of lumbar disc herniation (LDH) are gaining popularity. However, studies investigating the number of surgeries needed for surgeons to achieve proficiency in these procedures are lacking. This study aims to compare the early learning curve for UBE and UFE when treating LDH.

Methods: The learning curve for two fellowship-trained surgeons at our institution was retrospectively assessed for 160 consecutive patients (UFE: n = 100, UBE: n = 60) who underwent procedures between September 2020 and May 2023. Surgeon 1 first learned UBE, followed by UFE (S1BF), while Surgeon 2 first learned UFE and then UBE (S2FB). Operation time was evaluated as the primary outcome for determining the learning curve using cumulative sum (CUSUM) analysis. Secondary outcomes assessing endoscopic prowess include surgical outcomes, such as fluoroscopy usage times, postoperative hospital stays, the incidence of complications, and clinical outcomes, including visual analog scale (VAS) scores for back and leg pain, Oswestry disability index (ODI) score and modified MacNab criteria.

Results: The learning curve analysis identified the cutoff point in UBE at 14 cases and 11 cases for S1BF and S2FB, respectively, and in UFE at 31 cases and 27 cases, respectively. Without UFE or UBE experience, at the last follow-up, both the VAS back and leg pain in UFE were significantly higher than that in UBE (p < 0.05). Furthermore, the incidence of complications of UFE was also higher than that of UBE (29.0% vs. 7.1%). When surgeons have previous UFE or UBE experience, there was no significant difference in the clinical outcomes between UFE and UBE, and the complication rates were also similar (p > 0.05). After gaining UBE experience, the UFE performed by S1BF showed significantly better outcomes in fluoroscopy usage times (p = 0.024), surgical complications (p = 0.036), last follow-up VAS back pain (p = 0.003), and leg pain (p < 0.001) compared to S2FB. However, after gaining UFE experience, the S2FB only showed significant improvement in operation time (p = 0.041) during the process of learning UBE compared to S1BF.

Conclusions: Regardless of whether UBE or UFE is learned first, both techniques can significantly shorten the learning curve for the other technique. We recommend prioritizing the learning of UBE. Compared with UBE, the learning curve for UFE was significantly steeper and longer with higher incidence of complications in the early stage.

Objectives: The biomechanical mechanism of brace intervention on bone, muscle, and disc should be comprehensively considered for AIS patients. We aimed to developmentally construct a musculoskeletal finite element model of adolescent idiopathic scoliosis to simulate the coupling of corrective forces and analyze the mechanical properties of bone, muscle, and disc. Investigateing, more effective clinical interventions to break the vicious cycle of patients during growth.

Methods: A finite element model, including muscle, bone, and disc, was established using computed tomography data of a patient with RigoA3 adolescent idiopathic scoliosis. The three-point force coupling, antigravity, and bending effects of the Chêneau brace were simulated, and the correction force of the secondary lumbar bend was gradually reduced while observing the mechanical characteristics of bone, muscle, and disc. The correction force in line with symmetrical spine growth was comprehensively evaluated.

Results: The correction rate of the main thoracic (MT) curve, the intervertebral space height on the concave side of the vertebrae at the apex, and the stress ratio of the intervertebral discs were optimal when the maximum corrective pressure threshold was reached. However, the proximal thoracic (PT) curve was aggravated and the axial forces on the concave side were unbalanced. At this time, the biomechanical performance of the model is also not optimal. The correction rate of the Cobb Angle of the MT curve decreased with the decrease of the correction pressure in the lumbar region. When reduced to 25% of the maximum threshold, the convex side of disc stress, intervertebral space, and muscle axial force is more in line with the biomechanical mechanism of correction and can avoid sacrificing the PT curve.

Conclusions: Downward adjustment of the corrective force to the secondary lumbar curve, using the Chêneau brace, results in better primary thoracic curvature mechanics in the musculoskeletal finite element model, suggesting that breaking the vicious cycle of scoliosis progression to guide benign spinal growth is beneficial.

Objective: Currently, there is no research that includes a comprehensive three-dimensional fracture mapping encompassing all types of Pilon fractures. Moreover, the existing classification systems for Pilon fractures exhibit only moderate to fair consistency and reproducibility. Additionally, some of these classification systems fail to accurately depict the morphological characteristics of the fractures. This study aimed to create a fracture map encompassing all types of Pilon fractures by three-dimensional fracture mapping. In addition, this study conducted a finite element analysis of the normal ankle joint, and based on the distribution of fracture lines and the stress distribution at the distal tibia, proposed a new classification for Pilon fractures.

Methods: A retrospective analysis of Pilon fractures in our hospital from January 2018 to January 2024 was performed. A total of two hundred forty-four Pilon fractures were included, and their fracture lines were transcribed onto the tibia and fibula templates, and fracture maps and heat maps were created. A nonhomogeneous model of the ankle joint was constructed and verified, and the stress distribution on the distal tibia articular surface was measured and analyzed in three models (neutral, dorsiflexed, and plantarflexed model). Based on the fracture map and stress distribution, a five-column classification system for Pilon fractures was proposed, and the intraobserver and interobserver reliability was calculated using Cohen and Fleiss k statistics.

Result: The fracture line on the distal tibia articular surface showed a V-shaped distribution. One branch extended from the junction of the medial malleolar articular surface and the inferior tibial articular surface toward the medial malleolus. The other branch extended from the middle of the fibular notch to the posterior part of the medial ankle, toward the tibial shaft. The fibula fracture line mainly extended from the anterior and lower part of the lateral malleolus to the posterior and upper part. As evidenced by the neutral, dorsiflexed, and plantar flexion models, the stress on the posterolateral articular surface (posterolateral column) was low, while the majority of the stress was concentrated in the center. Three-column fractures were the most common, followed by two-column fractures. Using the five-column classification, the K-weighted values of interobserver and intraobserver analysis were 0.653 (p < 0.001) and 0.708 (p < 0.001), respectively.

Conclusions: In this study, the fracture line and morphological characteristics of Pilon fractures were analyzed in detail by three-dimensional mapping. In addition, this study conducted a finite element analysis of the stress distribution on the distal tibial joint surface of the normal ankle joint. Moreover, a novel classification system was proposed to reflect these findings. The new classification not only exhibits greater consistency, facilitating accurate communication of fracture characteristics among surgeons, but also aids in understanding the mechanisms of injury and formulating surgical strategies.

Objectives: Intramedullary nailing is preferred for treating elderly proximal humeral fractures, but secondary reductions are common, particularly in elderly and osteoporotic patients. This occurs due to the intramedullary nail fixation’s insufficient anti-varus and anti-rotational capacities and high stress at the bone–implant interface. We aim to enhance the anti-varus and anti-rotational stability of the fixation structure while reducing the stresses on the bone and internal fixation through structural design.

Materials and Methods: We developed a novel endosteal anatomical support nail (EASN) that integrates an endosteal torus construct into the proximal portion of the angle-stable proximal humerus nail. The endosteal torus construct includes endosteal anatomical support (EAS) with a flat plane that allows direct fixation of the humeral head fragments and is shaped to conform to the medial side of the medullary cavity of the proximal humerus. We conducted finite element analysis to assess the biomechanical stability of four constructs: EAS with a calcar screw (CS), EAS without CS, non-EAS with CS, and non-EAS without CS. This analysis determined the contribution of the EAS to the mechanical stability of the proximal humerus in two-part PHF with medial column disruption. Specimens were subjected to loads simulating partial-weight-bearing (as in rising from a chair or using crutches) and full-weight-bearing (as in rising from bed). We evaluated the stiffness of the construct, displacement at the fracture site, von Mises stress, and stress distribution.

Results: Under compressive or rotational loads, the EAS construct, with or without CS, was significantly stiffer than the non-EAS construct. Displacement at the fracture site was significantly less with the EAS fixation than with the non-EAS fixation. However, the stiffness and displacement at the fracture site of the EAS fixation without CS were comparable to those of the non-EAS construct with CS. The EAS construct reduced the load on the nail and decreased the risk of implant failure. Both von Mises stress and stress distribution were significantly lower following fixation with the EAS constructs.

Conclusions: This study introduces a novel EAS concept to enhance the anti-varus and anti-rotational capabilities of the humeral head and distribute stress at the bone–implant interface in treating elderly PHFs. This strategy shows promise based on our limited analysis.

Objective: Whether first coronal reverse vertebrae (FCRV) can directly cause biomechanical changes in adjacent segments remains unclear. The objective of this study was to explore the biomechanical changes in adjacent discs of the FCRV to better understand the stress distribution of adolescent idiopathic scoliosis (AIS).

Methods: According to the plain CT scan data of T8–T10 segment of an AIS patient, T9 was the FCRV, and a three-dimensional FE model was established accurately. The T8–T9 segment disc was defined as the adjacent upper disc (UD), axial section as half of the upper disc (HUD). Similarly, T9–T10 segment disc was the adjacent lower disc (LD), axial section as half of the lower disc (HLD). The biomechanical changes in adjacent discs of the FCRV under different loads were assessed.

Results: The maximum Von-Mises stress values of the LD were greater under various loads than those of the HLD, UD, and HUD. The average stress on the LD was greater than that of the other discs under the left lateral bending (LLB) or right lateral bending (RLB) load. It was noted that the concave side of the LD was subjected to greater stress under the neutral standing or LLB load compared with convex side. Additionally, the concave side of the LD was subjected to greater stress under the LLB or RLB load compared with that of other discs. Interestingly, the same trends were observed for the convex side of the LD.

Conclusions: FCRV caused LD to take on greater stress magnitudes. The stress showed a trend of local concentration, which was in the concave side of the scoliosis. These findings could contribute to further treatment planning for the patient and aid physicians’ management decision-making.

Objective: Rotator cuff retear after arthroscopy repair is a difficult complication that is often due to poor tendon–bone healing. Decellularized amniotic membrane (DAM) has a variety of bioactive substances which have great potential to enhance tendon–bone healing. However, DAM has three layers, of which the middle basement layer is dense and thick. Whether DAM will hinder tendon–bone healing of rotator cuff after surgical repair is unclear. Our study aims to investigate the effect of DAM on tendon–bone healing of the rotator cuff after surgical repair.

Methods: Thirty-three Sprague–Dawley (SD) rats were selected to establish unilateral supraspinatus (ST) tear models and were randomly treated with only suturing repair (OSR group, n = 11), and suturing repair with DAM placed between the ST and bone (DAM group, n = 11). In the normal control group (NCT group, n = 11), the supraspinatus was only exposed but not detached or repaired. After 4 weeks the rats were sacrificed. The assessment of specimens was conducted by micro-CT analysis, histopathological evaluation, and biomechanical testing.

Results: The DAM group had a significantly higher ultimate load to failure, new bone volume, and histological evaluation at 4 weeks after surgery than the OSR group. When comparing the DAM group to the NCT group, the DAM group performed slightly worse in biomechanical testing, micro-CT analysis, and histological evaluation.

Conclusion: When placed between tendon and bone at the rotator cuff footprint, DAM, despite its dense and thick basement layer, does not impede tendon–bone healing after surgical repair for rotator cuff injury, but rather promotes increased healing quality and biomechanical properties. However, the healing quality and biomechanical properties are still lower than that of the normal rotator cuff, and further improvement should be made to the application strategy of a DAM.

Objective: The clivus is trapezoidal in shape with uneven bone structure, the optimal number and position of screws for clival fixation are not clear. Therefore, this study aims to explore the optimization clival screw fixation method for occipitocervical instability using finite element analysis.

Methods: Seven finite element models were developed to evaluate biomechanical properties of clival screw fixation for treating occipitocervical stability, including (i) one clival screw fixation A1 and A2 models; (ii) two clival screws fixation B1 and B2 models; (iii) three clival screws fixation C1 and C2 models; (iv) four clival screws fixation D1 model. Loads of 1.5 Nm were applied to the model fRoM different directions to induce flexion, extension, lateral bending, and axial rotation movements.

Results: The regular triangle C1 type three clival screws fixation exhibited great stability, with RoM of 4.20° in flexion, 5.80° in extension, 0.85° in lateral bending, and 1.60° in axial rotation. The peak stress on the internal fixation devices were relatively low, with maximum screw stress of 194 MPa in flexion, 276 MPa in extension, 180 MPa in lateral bending, and 213 MPa in axial rotation; the maximum plate stress were 126, 554, 426, and 378 MPa, respectively. The areas with higher stress were mainly concentrated at the robust neck section of the plate.

Conclusion: The triangular configuration of three clival screws fixation represented the optimized anterior occipitocervical fixation method through the clivus, offering superior biomechanical stability, lower stress on the devices and dispersed stress distribution in the occipitocervical region.

Background: High tibial osteotomy (HTO) is a surgical procedure for treating certain knee conditions. Proper execution of HTO can preserve joint function and delay or avoid the need for total knee replacement. This study compared different 3D printing techniques (fused deposition modeling, selective laser sintering, and direct metal laser sintering) and a navigation system for their suitability in assisting HTO surgeries.

Methods: Tibial saw-bones were used as models, and surgical guides and the navigation system were employed during the procedures. Six parameters (planning time, manufacturing time, delivery time, material cost, operation time, and accuracy) were evaluated. One-way analysis of variance (ANOVA) and t-test were used for the analysis.

Results: The results showed that the metal surgical guides had the highest accuracy (angle differences mean, 2.4°) and operation time (mean 9.75 min), followed by plastic guides, classic guides, and the navigation system. The differences in accuracy were attributed to factors like rigidity, melting point, and errors during incisions.

Conclusions: The study recommended metal surgical guides as the best option for assisting HTO due to their accuracy and operation time. And the results have implications for orthopedic surgeons performing HTO surgeries, as they can use this information to improve postoperative outcomes, such as mechanical axis alignment and quality of life for HTO patients.

Objective: Gap balancing is a vital process during mobile-bearing unicompartmental knee arthroplasty (MB-UKA). However, this process commonly depends on the surgeon’s experience and lacks specific unified standards. This study aimed to propose and evaluate a novel “measured resection” method for gap balance in MB-UKA.

Methods: This prospective study included 49 consecutive patients (52 knees) who underwent MB-UKA from February 1, 2023, to September 1, 2023. Gap balance was achieved by the traditional “two-finger” method (Group 1, 26 knees) or the measured resection method (Group 2, 26 knees). The novel “measured resection” method was performed by measuring the thickness of the resected posterior femoral condyle and resected medial posterior tibial plateau to assess proper meniscal bearing thickness. Data were collected at baseline and the 6-month follow-up. Prosthetic angles, range of motion (ROM), visual analog scale (VAS) score, Oxford knee score (OKS), and Global Perceived Scale (GPE) were used to evaluate clinical outcomes. Independent samples t-test and Mann–Whitney U test were used to compare the differences.

Results: There were significant improvements in all measured outcomes at the 6-month follow-up from baseline in both groups (p < 0.01). Patients using measured resection method showed better ROM (130° vs. 120°, p = 0.007), VAS score (1 vs. 2, p = 0.013), and OKS scores (39.9 vs. 38.1, p = 0.013) at 6-month follow-up than the traditional “two-finger” method group. The prosthetic angles, ROM improvement, and GPE showed no significant difference between the groups (p > 0.05).

Conclusions: The measured resection method is a reliable method for assisting surgeons in choosing the ideal meniscal bearing thickness in MB-UKA to achieve proper gap balance and gain better clinical outcomes.

Trial Registration: ClinicalTrials.gov (NCT03815448)

Objective: Despite several surgical options, there has yet to be a consensus on the best treatment for femoral neck fracture (FNF) due to higher complication rates compared to other bone fractures. This study aims to examine the possible consequences and solution suggestions of changing screws during surgery for various reasons in FNF surgical treatment from a biomechanical perspective.

Method: FNF and treatment materials were analyzed biomechanically using a package program based on the finite element method (FEM). This study created a solid model with images of femur bone tomography. Dynamic hip screws (DHS), cannulated screws (CCS), and medial buttress plates (MBP) were obtained by making three-dimensional designs. The required elements for the models were assigned, and the material properties of the elements were defined. The solutions were obtained as crack distance and deformation results after defining the boundary conditions and applying the necessary loading.

Results: The strain and crack distance values created by six models on the fracture line under different parameters were obtained, and the numerical results were evaluated. The DHS and CCS models produced the highest crack distance and deformation values when all screws were loose. The lowest values were obtained in the intact-85 model when all CCS were tight. When the results are evaluated, it is seen that the MBP has a decreasing effect on the results. Mechanical evaluation of six different options used in femoral neck fractures was performed. 85 mm CCS applied to our standard model gave the best results, while the use of 80 mm CCS in the same model showed promising results compared to other models. It is understood that CCS have the best stability even in loosening models with the medial support plate. Different models are from intact-85 mm DHS+1CS+MBP to DHS+1CS, which was worked with LSR+USR-2, according to decreasing stability.

Conclusion: This study offers various biomechanical solutions to possible intraoperative problems in FNF treatment. The following results were obtained from the study data. When the CCS needs to be lengthened or replaced, it is appropriate to use the CCS with the MBP. A single anti-rotation screw is sufficient for lag screw extensions of the DHS plate, and the MBP may be a savior procedure in surgery.

Objectives: Edema after shoulder arthroscopic surgery poses concerns due to its potential complications such as compartment syndrome, nerve damage, and respiratory issues. This study aimed to investigate the acute accumulation of subcutaneous fluid after shoulder arthroscopy.

Methods: A prospective cohort study, providing Level III evidence was conducted on 50 patients undergoing arthroscopic shoulder surgery under interscalene block anaesthesia from September to December 2023. The patients were divided into two groups: rotator cuff repair (RCR, n = 29) and labral repair for shoulder instability (LR, n = 21). Subcutaneous fluid levels were measured preoperatively, postoperatively, and at discharge (24 h postsurgery) using the MoistureMeterD Compact at the neck, pectoral region, deltoid area, cubital fossa, and carpal tunnel. Data on surgery duration and irrigation fluid volume were documented. In the statistical analysis, repeated measures ANOVA and the independent-samples t-test were applied to compare parametric data, while the Friedman test and Mann–Whitney U test were used for nonparametric data.

Results: The average operation time was 29.0 ± 12.1 min for RCR and 30.0 ± 10.9 min for LR, with average irrigation fluid use of 3.8 ± 0.9 and 4.0 ± 0.7 L, respectively (both p > 0.05). There was no increase in subcutaneous edema in the neck and deltoid region in both groups. At discharge, the percentage of subcutaneous fluid increased in the cubital fossa (p = 0.04 for RCR; p < 0.001 for LR) and carpal tunnel (both p < 0.001) in oth groups, whereas pectoral edema increased only in the labral repair group (p = 0.04).

Conclusions: Subcutaneous pectoral edema can occur following arthroscopic labral repair, and increased fluid levels in the cubital fossa and carpal tunnel were observed in both rotator cuff and labral repairs, even in the absence of prolonged surgery or excessive irrigation fluid use. These findings highlight the need for careful postoperative management of edema after shoulder arthroscopy, particularly for labral repairs, with special attention to the pectoral region, cubital fossa, and carpal tunnel to prevent potential complications.

The registry is sponsored by the United States National Library of Medicine (www.clinicaltrials.gov); Registry Name: Examination of Edema After Arthroscopic Shoulder Surgery ID: NCT06014203.

Objective: The pedicle screw insertion technique has evolved significantly, and despite the challenges of precise placement, advancements like AR-based surgical navigation systems now offer enhanced accuracy and safety in spinal surgery by integrating real-time, high-resolution imaging with virtual models to aid surgeons. This study aims to evaluate the differences in accuracy between novel AR-guided pedicle screw insertion and conventional surgery techniques.

Methods: A randomized controlled trial was conducted from March 2019 to December 2023 to compare the efficacy of AR-guided pedicle screw fixation with conventional freehand surgery using CT guidance. The study included 150 patients, aged 18–75, with 75 patients in each group. The total number of pedicle screws planned for the clinical trial placement was 351 and 348 in the experimental and control groups. The safety and efficacy of the procedures were evaluated by assessing screw placement accuracy and complication rates.

Results: In the full analysis set (FAS) analysis, the difference in the excellent and good rates of screw placement (experimental group – control group) and 95% confidence interval was 6.3% [3.0%–9.8%], with a p value of 0.0003 for the superiority test. In the FAS sensitivity analysis, the success rate was 98.0% (344 out of 351) in the experimental group and 91.7% (319 out of 348) in the control group, with a difference and 95% confidence interval of 6.3% [2.9% and 9.8%, respectively]. In the per-protocol set (PPS) analysis, the difference in the excellent and good rates of screw placement between the experimental and control groups, and the 95% confidence interval was 6.4% [3.3%–9.5%], with a p value of 0.0001 for the superiority test. In the actual treatment set (ATS) analysis, the excellent and good rates of screw placement were 99.1% in the experimental group and 91.7% in the control group. The difference in the excellent and good rates of screw placement (experimental group – control group) and 95% confidence interval was 7.3% [4.1%–10.6%], with a p value of < 0.0001 for the superiority test.

Conclusions: The AR surgical navigation system can improve the accuracy of pedicle screw implantation and provide precise guidance for surgeons during pedicle screw insertion.

Objective: According to Association Research Circulation Osseous (ARCO) staging, patients with ARCO III osteonecrosis of femoral head (ONFH) have joint pain and dysfunction due to the collapse of femoral head. Current hip preservation surgeries are not satisfying in the treatment of ARCO III ONFH according to the long-term follow-up. In our practice, we focused on reconstructing femoral head by restoring the round shape of femoral head and subsequently preventing the development of hip arthritis. To lift the collapsed femoral head and postpone the potential total hip arthroplasty, we practiced Jack surgery, combining surgical hip dislocation, removal of necrotic bone, impaction bone grafting, and lifting the cartilage of femoral head.

Methods: From February 2019 to July 2022, 13 patients (15 hips) who received Jack surgery in the research center were included in this retrospective study. Follow-up was conducted every 3 months after surgery for imaging and clinical evaluation. The differences between visual analogue scale (VAS) and Harris hip score (HSS) before and after surgery were compared to observe whether the femoral head collapsed and whether osteotomy healed after surgery. Severe collapse of the femoral head (> 2 mm) or receiving total hip arthroplasty (THA) was defined as failure of hip preservation therapy. An Independent sample t-test was used to compare the data, and the chi-square test was used for categorical data.

Results: All the 13 patients successfully completed the surgery and were followed up. The average time of follow-up was 36.46 ± 16.87 months (ranging from 14 to 66 months). HSS was assessed 12 months after surgery: excellent in 1 patient with 1 hip; good in 9 patients with 11 hips; modest in 3 patients with 3 hips. To the last follow-up, the VAS scores decreased from 6.17 ± 1.02 to 2.08 ± 0.90 (p < 0.001), HSS increased from 46.69 ± 4.15 to 89.77 ± 2.86 (p < 0.001). No deep infection, fracture, osteotomy nonunion, nerve injury, deep vein thrombosis, pulmonary embolism, or other complications occurred.

Conclusion: For young patients with ONFH of ACRO III, this surgical technique can effectively restore the original shape of the femoral head and achieve satisfactory hip function in the short term. The mechanism is similar to jacking the roof of a house; thus, we named it “Jack surgery”.

Background: Postoperative spinal epidural hematoma (SEH) is a rare but serious complication following lumbar surgery, with cauda equina syndrome (CES) being one of its most devastating outcomes. While CES typically presents with a combination of bladder and/or bowel dysfunction, diminished sensation in the saddle area, and motor or sensory changes in the lower limbs, atypical cases with isolated urinary symptoms are less recognized and pose significant diagnostic challenges.

Case Presentation: We report the case of a 46-year-old male who developed CES following lumbar microdiscectomy, presenting solely with urinary retention, without the classic signs of lower limb weakness or perineal sensory loss. Initial symptoms were attributed to postoperative urinary issues, delaying the diagnosis of CES. On postoperative day 7, magnetic resonance imaging (MRI) revealed SEH, and emergency hematoma evacuation was performed. Despite the delayed intervention, the patient made a full neurological recovery, with bladder and bowel functions restored by 3 months postoperatively.

Conclusion: This case highlights the importance of recognizing CES in patients with isolated urinary dysfunction after lumbar surgery, even when typical neurological symptoms such as lower limb weakness or perineal sensory loss are absent. Early detection and prompt surgical intervention are critical, as delayed diagnosis may result in permanent neurological deficits. Moreover, this case underscores the need for vigilant postoperative monitoring, especially of urinary function, as isolated urinary symptoms may signal early CES. Maintaining a high index of suspicion for CES, even in atypical presentations, can facilitate timely diagnosis and improve patient outcomes. Furthermore, this case highlights the need for continued research into the prevention of SEH and the development of more robust diagnostic criteria for CES in postoperative patients. Future studies should focus on developing more comprehensive guidelines for monitoring postoperative patients, especially regarding urinary function, to aid in the early detection of CES.