Biomechanical effects of a novel standalone posterior lumbar facet joint stabilization device: an in vitro cadaveric study.

OBJECTIVE: Although pedicle screw-rod (PSR) instrumentation remains the gold standard, it has complications, including pedicle breach and facet joint violation. There is current interest in facet joint stabilization with the potential to create a less invasive, natural arch of fixation that may avoid the complications of PSR instrumentation. This study examined the stabilizing potential of a novel facet joint fixation device for single-level (L4-L5) fixation in a human cadaveric model. METHODS: Six L3-S1 specimens were tested multidirectionally under pure moment loading (7.5 Nm) in 3 conditions: 1) intact, 2) L4-L5 facet fixation without screws, and 3) L4-L5 facet fixation with screws. L4-L5 intervertebral disc angles were measured radiographically. Range of motion (ROM) and disc angles were compared using repeated-measures analysis of variance analysis, with statistical significance p<0.05. RESULTS: Compared to the intact condition, L4-L5 bilateral facet fixation without or with screw fixation significantly reduced L4-L5 angular ROM in all directions (p≤0.003). No significant differences were observed in cranial and caudal adjacent-segment ROM (p≥0.08) except for L3-L4 fixation in extension, which exhibited small motion increases (0.12° without screws, 0.1° with screws) versus the intact condition (p≤0.003). No statistically significant differences were observed in disc angle values between the conditions (p=0.87). CONCLUSIONS: Bilateral lumbar facet fixation with and without supplemental transfacet screw fixation provided significant stability. Cranial and caudal adjacent-level ROM was not influenced by facet fixation except for a slight increase in cranial segment motion during extension. Facet fixation did not alter the lordotic intervertebral disc angle at the instrumented level.

Anterior odontoid screw fixation of a type III odontoid fracture aided by transoral digital manipulation: illustrative case.

BACKGROUND: Odontoid process fractures make up 10%-20% of all cervical spine fractures, with type III fractures having a considerable amount of heterogeneity. Most simple type III fractures can be managed nonoperatively. However, 21% of complex type III fractures with significant displacement and angulation are inadequately treated with external immobilization and require surgery. Achieving a reduction via traction can pose a great challenge during intraoperative manipulation, especially when presentation is delayed. OBSERVATIONS: A 36-year-old male patient, who presented 2 weeks after a motor vehicle crash, had a Glasgow Coma Scale score of 14 and intact motor and sensory function. A craniocervical computed tomograpy scan revealed a normal brain with a type III odontoid fracture. The patient underwent anterior odontoid screw fixation (AOSF) aided by a transoral digital manipulation to achieve a reduction of the irreducible proximal fracture segment at 8 weeks postinjury. The treatment resulted in preserved neurological function and a satisfactory odontoid fracture reduction. LESSONS: Delayed presentation of a complex type III odontoid fracture can be challenging to treat; however, AOSF with the aid of transoral digital manipulation of the irreducible proximal segment can help to achieve good reduction and fusion with the preservation of neurological function in a young patient. https://thejns.org/doi/10.3171/CASE24294.

Prone Single Position Approach to Lateral Lumbar Interbody Fusion: Systematic Review and Meta-Analysis.

BACKGROUND: Lateral lumbar interbody fusion (LLIF) with posterior screw fusion is a safe and effective treatment for patients suffering from degenerative spine disorders. While LLIF has been shown to restore disc height, decompress neural components, correct sagittal imbalances, and improve pain scores, the approach requires repositioning patients for posterior pedicle fixation, which requires 2 separate surgeries. The evolution of surgical techniques, navigation, and robotics has allowed for a single position approach to LLIF with the patient in the prone position. The purpose of this study was to perform a systematic review and meta-analysis comparing the prone single position (PSP) LLIF approach to the dual position LLIF approach. We hypothesized that PSP LLIF will have a reduced operative time, complication rate, and blood loss compared with the dual position LLIF procedure. METHODS: A systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. PubMed and Embase databases were searched with key terms: (lateral AND [interbody OR "inter body"] AND lumbar AND fusion) AND (prone OR single). Results were extracted and reviewed by 2 authors (MR and RB) per selection criteria. Patient demographics were extracted from the selected studies, along with surgical, patient-reported, and radiographic outcomes. A meta-analysis was performed using an unstandardized mean difference or log odds ratio with a confidence level of 95%. RESULTS: Fifteen studies were included in the systematic review and 5 studies compared PSP LLIF to dual position LLIF for meta-analysis. PSP LLIF had a reduced operative time and length of stay compared with the dual position approach, although there was no significant reduction in estimated blood loss. Additionally, PSP LLIF improved lumbar lordosis more effectively than dual position LLIF. There was no difference in segmental lordosis or pelvic tilt. There was no difference in intraoperative complications, postoperative complications, or reoperations. CONCLUSIONS: PSP LLIF reduces operative time and length of stay, with no relative increase in complications or reoperations compared with the dual position approach. Additionally, PSP LLIF improves lumbar lordosis relative to dual position LLIF, which may improve functional outcomes and reduce the risk of developing adjacent segment disease. CLINICAL RELEVANCE: The associated operative and postoperative benefits of PSP LLIF may improve long-term outcomes of patients undergoing spinal fusion.

Fixation of Gardens Type 4 Intracapsular Neck of Femur Fracture Using the GS Kulkarni Controlled Dynamic Hip Screw System.

The goal for surgical treatment of femoral neck fractures is achieving union through an anatomic reduction and stable fixation while avoiding osteonecrosis. This report describes the case of a 50-year-old male who presented with pain and swelling in his right hip and inability to bear weight over his right lower limb following a road traffic accident. The X-ray revealed a right-sided femoral neck fracture (Garden Type IV and Pauwels Type III). The patient was surgically treated with the GS Kulkarni (GSK) controlled dynamic hip screw. On follow-up, the bone healing time was 14 weeks and the patient achieved a Harris hip score of 93.65 with significant improvement.

Simultaneous Single-Position Oblique Lumbar Interbody Fusion and Percutaneous Pedicle Screw Fixation under O-Arm Navigation for Modified MISDEF Type II Adult Degenerative Scoliosis: Case Series and Surgical Technique.

PURPOSE: Oblique lumbar interbody fusion (OLIF) has become a popular technique for treating adult degenerative scoliosis (ADS), but traditional OLIF technology often requires repositioning for one-stage or staged posterior fixation. The objective of this pilot study was to describe the surgical technique of simultaneous single-position OLIF and percutaneous pedicle screw fixation (OLIF 360) under O-Arm navigation for modified MISDEF type II ADS. METHODS: Between June 2022 and December 2023, six patients classified as having modified MISDEF type II ADS underwent OLIF 360 assisted by O-Arm navigation at our institution. Intraoperative blood loss, duration of operation, and complications related to the OLIF 360 procedure were recorded. The preoperative and postoperative spinal pelvic parameters were measured using X-rays. The accuracy of pedicel screws was recorded in accordance with the modified Gertzbein-Robbins classification on CT. Postoperative MRI was performed to evaluate the indirect decompressive effect. The Japanese Orthopedic Association score for low back pain was used to evaluate surgical outcomes. RESULTS: Navigated OLIF 360 were performed in six ADS patients with 44 percutaneous pedicel screws and 16 cages placement, including four women and two men. The mean operation time was 160.83 ± 33.23 min, and the mean blood loss was 111.67 ± 39.71 mL. Postoperative spinal pelvic parameters and spinal stenosis degree improved significantly on X-ray and MRI. All screws were clinically acceptable according to the Gertzbein-Robbins classification, with 92.7% grade A and 7.3% grade B. No serious intraoperative and postoperative adverse events were recorded in all patients. The JOA scores for low back pain of all patients were significantly improved at postoperative 1 month and the final follow-up. CONCLUSION: We report on a case series and describe navigated OLIF 360 in treating modified MISDEF type II ADS patients. Navigation-assisted OLIF 360 has shown encouraging surgical outcomes with good spinal imbalance correction and indirect decompression.

Comparative effectiveness of oblique lumbar interbody fusion with anterior screw fixation versus percutaneous pedicle screw fixation for treating lumbar degenerative diseases: A systematic review and meta-analysis.

PURPOSE: Lumbar degenerative diseases impose a substantial health burden, prompting the exploration of advanced surgical approaches such as Oblique Lumbar Interbody Fusion (OLIF). This meta-analysis aims to evaluate the comparative efficacy of OLIF with anterior screw fixation (OLIF-AF) against OLIF with posterior pedicle fixation (OLIF-PF) in addressing these conditions. METHODS: A systematic search across multiple databases identified five studies meeting inclusion criteria, incorporating a total of 271 patients. Comparative analysis encompasses primary and secondary outcomes related to fusion rates, intraoperative parameters, patient-reported measures, and radiographic assessments. RESULTS: Primary outcome analysis demonstrated no statistically significant difference in total fusion rates between OLIF-AF and OLIF-PF. However, secondary outcomes revealed distinct advantages in OLIF-AF, showcasing lower intraoperative blood loss and reduced operative times compared to OLIF-PF. Nonetheless, patient-reported outcomes, encompassing measures such as pain scores and functional assessments, as well as radiographic parameters, exhibited no significant variations between the two techniques. CONCLUSION: While OLIF-AF displayed favorable results in intraoperative parameters, such as reduced blood loss and shorter operative times, it did not significantly differ in patient-reported outcomes and radiographic assessments compared to OLIF-PF. Interpretation of findings must consider limitations in sample sizes and study heterogeneity. Future investigations with larger, more diverse cohorts and extended follow-ups are imperative to confirm these preliminary findings and comprehend the actual clinical impact of these OLIF techniques in managing lumbar degenerative diseas.

Arthroscopic Suture Anchor Fixation Results in Similar Clinical Outcomes, Less Range of Motion Limitation but Poorer Quality of Reduction compared to Open Screw Fixation for Acute Large Anterior Glenoid Rim Fractures.

BACKGROUND: The purpose of the present study was to retrospectively compare the clinical and radiological outcomes of arthroscopic suture anchor fixation and open screw fixation for acute large anterior glenoid rim fractures. METHODS: This study enrolled patients with acute large anterior glenoid rim fractures treated with arthroscopic suture anchor fixation (group A) or open screw fixation (group O) from January 2013 to June 2020 with a minimum follow-up of＞2 years. The Subjective Shoulder Value (SSV), American Shoulder and Elbow Surgeons (ASES) score, Rowe score, Constant score, range of motion (ROM), recurrent instability rate, and complications were recorded as clinical results. The quality of the postoperative reduction, reconstructed glenoid sizes, rate of fracture healing, and progression of osteoarthritis (OA) were evaluated as radiological outcomes. RESULTS: This retrospective study included 66 patients, including 37 in Group A and 29 in Group O with a mean follow-up of 46.9 (range, 24.3-94.2) months and a mean patient age of 46.8 (range, 21-69) years. No significant differences were found in the clinical outcomes between the two groups. A significant ROM limitation in all planes was found in both groups and group O showed more limitations in external rotation at the side (ERs) (18° vs. 10°, P = 0.002). The reduction quality was better in group O (P < 0.001). However, there was no significant difference between the two groups in terms of reconstructed glenoid size (101.6% ± 4.6% vs. 100.6% ± 7.1%, P = 0.460) and the rate of OA progression (26.9% vs. 20%, P = 0.525). CONCLUSION: Arthroscopic suture anchor fixation and open screw fixation achieved similar clinical outcomes, reconstructed glenoid sizes, and OA progression in patients with acute large anterior glenoid rim fractures. Arthroscopic suture fixation showed a poorer quality of reduction but less ERs limitations.

Nondestructive acoustic modal analysis for assessing bone screw stability: An ex vivo animal study.

Conventional insertion torque and pull-out tests are destructive and unsuitable for clinical bone screw fixation. This study evaluates screw stability using acoustic modal analysis (AMA) and Periotest compared to traditional methods in an ex vivo animal model. Titanium self-tapping screws (STS) and nonself-tapping screws (N-STS) were implanted in the proximal tibia of 12 rabbits. Four testing methods were used to assess screw stability: peak insertion torque (PIT) during implantation, AMA for natural frequency (NF), Periotest for Periotest value (PTV), and pull-out test for peak pullout force (PPF). Euthanization was performed at 0 (primary stability), 4, and 8 weeks (secondary stability). No significant difference in primary stability was found between STS and N-STS except for AMA (STS: NF 2434 ± 67 Hz, N-STS: NF 2572 ± 43 Hz; p = 0.62). Secondary stability increased significantly over time for both screw types (4-week: NF 3687 ± 36 vs. 3408 ± 45 Hz, PTV 1.4 ± 1.6 vs. -1.5 ± 1.8, PPF 236 ± 29 vs. 220 ± 34 N; 8-week: NF 3890 ± 39 vs. 3613 ± 31 Hz, PTV -3.2 ± 2.5 vs. -2 ± 4.3, PPF 248 ± 25 vs. 289 ± 28 N). Higher NF values for given PTV/PPF indicate potential clinical advantages. Significant differences between primary and secondary stabilities suggest osteointegration was mainly achieved in the 4-week group.

Surgical Outcomes of Syndesmotic Fixation of Ankle Fractures Using Syndesmotic Screws Versus Suture Button Devices.

INTRODUCTION: Ankle fractures associated with disruption of the syndesmotic complex could potentially have poorer outcomes if missed or malreduced at the time of surgery. Favourable results have been reported for the suture button (SB) technique and may provide advantages over standard screw fixation of the syndesmosis, although this remains the gold standard method in many units. AIM: To compare the outcomes of syndesmotic screws (SS) with SB fixation of the syndesmosis during ankle fracture fixation at a high-volume orthopaedic department of a Scotland trauma unit. METHOD:  A cross-sectional, retrospective study looking at ankle fracture fixations was undertaken at the Clyde Trauma Unit, Paisley. Relevant information was obtained from electronic patient records for 457 ankle fracture patients between August 2019 and February 2022 and followed up for six months. The digital patient archive system (PACS) was used for evaluating radiographs. Patients were divided into two groups depending on whether they had an SS or SB fixation of their syndesmosis. We focused on the surgical and radiological outcomes following syndesmotic fixation as no functional scores following surgery were conducted on the patients. RESULT: Out of the entire study group, 26.3% (120/457 patients) required syndesmotic fixation. Within the syndesmotic fixation group, 70.8% (85/120 patients) underwent SS fixation, and 29.2% (35/120 patients) had an SB fixation. Both groups were statistically well-matched. Additionally, 21.1% (18/85) of SS fixation went on to have a second surgical procedure (four fixation failures, five planned removals, five for pain/stiffness, two infections, and two metalwork breakage/migration), whereas 8.6% (3/35) of the SB fixation group had a secondary procedure - two for fixation failures and one for infection. CONCLUSION: We reported a higher incidence of associated syndesmotic injury in our series of 457 ankle fractures than previously described. There were significantly fewer sequelae in the SB group compared to the SS fixation group (P = 0.0464). Although we did not observe a statistically significant difference in the rate of reoperation (P = 0.1184), this is likely due to the small numbers in the SB group. Our study suggests that SB fixation may be associated with a lower rate of reoperation for post-op complications such as metalwork failure, pain, and stiffness (21.1% SS vs 8.6% SB). Regardless of the fixation method used, accurate reduction of the ankle mortice and syndesmosis is a key step to a successful surgical outcome.

Risk factors for malalignment after intramedullary nail treatment of distal tibia fractures with associated fibula fractures.

PURPOSE: Malalignment of distal tibia fractures can lead to malunion/nonunion or alter the limb mechanical axis which may cause arthritis. Proposed methods to decrease malalignment include fibular fixation or multiplanar interlocking screws, however these remain controversial. This study aimed to identify factors associated with malalignment in distal tibial fractures with associated fibular shaft fractures. METHODS: A retrospective review was performed of distal tibia fractures with associated fibular shaft fractures treated with intramedullary nailing at two level one trauma centers between 2015 and 2019. Cases involving malalignment (> 5° of deviation from anatomic axis on either coronal/sagittal axis) on final follow-up (minimum three months postoperatively) were compared to those without malalignment with regard to demographics, fracture characteristics, intraoperative characteristics, and complications. RESULTS: The rate of malalignment was 13%. On multivariate analysis, multiplanar distal interlocking screw fixation (odds ratio [OR], 0.18; 95% confidence interval [CI] 0.03-0.92) was associated with a decreased rate of final malalignment, while nail diameter > 10 mm was associated with a higher rate (OR, 4.05; 95% CI 1.25-13.11). Fibular fixation was not associated with malalignment. CONCLUSION: Multiplanar distal interlocking screws may protect against malalignment. Fibula fixation does not appear associated with a decreased rate of malalignment in distal tibia fractures treated with intramedullary nails. LEVEL OF EVIDENCE: III.

Effective method of pedicle screw fixation in patients with neurologically intact thoracolumbar burst fractures: a systematic review of studies published over the last 20 years.

OBJECTIVE: To conduct a systematic review of studies on various posterior pedicle screw fixation (PSF) methods used for treating neurologically intact thoracolumbar burst fractures and to identify the most effective and safe approaches. METHODS: We conducted a systematic review adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, with the study registered in PROSPERO (CRD42024531093). The inclusion criteria were: (1) publication dates from January 1, 2004, to December 31, 2023; (2) availability of full-text articles in English; (3) thoracolumbar burst fractures without neurological deficits; (4) patients aged over 18; (5) reports on treatment outcomes or complications; (6) a mean follow-up period of at least 12 months. RESULTS: A total of 69 articles covering 116 patient groups were included. Our analysis highlighted the advantages of short-segment fixation without fusion over monosegmental, short-segment and long-segment fusion in terms of shorter operation times and reduced intraoperative blood loss (p = 0.001 and p < 0.001, respectively). Extensive fusion was associated with a significantly higher frequency of deep surgical site infections compared to other PSF methods (p = 0.043). Percutaneous pedicle screw fixation, applied to patients with lower body compression rates and kyphotic deformities, led to less potential for correction (p = 0.004), yet significantly decreased blood loss (p = 0.011), operation duration (p < 0.0001), and hospitalization duration (p < 0.0001). No significant benefits were observed with the use of additional intermediate screws in short-segment PSF. CONCLUSIONS: Short-segment pedicle screw fixation could be the optimal surgical treatment method for neurologically intact thoracolumbar burst fractures. The use of posterior lateral fusion in this context may increase the deep surgical site infection rate without reducing the frequency of implant-related complications or improving long-term treatment outcomes. The percutaneous approach remains the preferred technique; however, its limited reduction capabilities should be carefully considered during surgical planning for patients with severe kyphotic deformities. The application of intermediate screws in such patients has not demonstrated significant advantages. Removing the fixation system has not led to a significant decrease in implant-related complications or improvement in quality of life. The data obtained from the systematic review may assist surgeons in selecting the most appropriate surgical treatment method for patients with neurologically intact thoracolumbar burst fractures, thereby avoiding ineffective procedures and improving both short-term and long-term outcomes.

Oblique lumbar interbody fusion combined with anterolateral screw fixation and stress endplate augmentation for treating degenerative lumbar spondylolisthesis with osteoporosis.

PURPOSE: To evaluate the outcomes of Oblique lumbar interbody fusion (OLIF)combined with anterolateral screw fixation (AF) and Stress Endplate Augmentation(SEA) versus OLIF-AF in the treatment of degenerative lumbar spondylolisthesis (DLS)with osteoporosis (OP). METHODS: 30 patients underwent OLIF-AF-SEA (SEA group) were matched with 30 patients received OLIF-AF (control group), in terms of sex, age, body mass index (BMI) and bone mineral density (BMD). Clinical outcomes including visual analog scale (VAS) score of the lower back pain (VAS-LBP), leg pain (VAS-LP), and Oswestry Disability Index (ODI) were evaluated at different postoperative intervals and comparedwith their preoperative counterparts. Radiographic outcomes such as disk height (DH), slip distance (SD), lumbar lordosis (LL), segmental lordosis (SL), cage subsidence (CS) rate and fusion rate were evaluated at different postoperative intervals and compared with their preoperative counterparts. RESULTS: SEA group presented to be better at 3-month and 12-month follow-up, the VAS-LBP, VAS-LP and ODI scores of the SEA group were significantly lower than the control group (3-month SEA vs control: 2.30±0.70 vs 3.30±0.75, 2.03±0.72 vs 2.90±0.76,15.60±2.36 vs 23.23±3.07, respectively, all p<0.05. VAS-LBP and ODI 12-month SEA vs control: 1.27±0.74 vs 1.93±0.58, 12.20±1.88 vs 14.43±1.89,respectively, all p<0.05). At 24-month follow-up, both groups showed no difference in fusion rate (83.33% vs 90.00%, p=0.45), while SEA group showed a lower CS rate (13.33% vs 53.33%, p<0.05). CONCLUSION: OLIF-AF-SEA was safe with no adverse effects and resulted in lower CS rate and better sagittal balance. OLIF-AF-SEA is a promising surgical method for treating patients with DLS-OP.

[Oblique Lumbar Interbody Fusion Combined With 4-Screw Fixation for Treating Two-Level Degenerative Lumbar Diseases:A Finite Element Study].

Objective To demonstrate the feasibility of oblique lumbar interbody fusion (OLIF) combined with 4-screw fixation for treating two-level lumbar degenerative diseases.Methods An intact finite element model of L3-S1 (M0) was constructed and validated.Then,we constructed the M1 model by simulating OLIF surgery at L3/4 and L4/5 segments on the M0 model.By attachment of posterior 4-screw or 6-screw fixation to the M1 model,three 4-screw fixation models (M2-M4) and one 6-screw fixation model (M5) were established.The segmental and overall range of motion (ROM) and the peak von Mises stresses of superior endplate,cage,and posterior screw-rod were investigated under each implanted condition.Results Under the motion modes of forward flexion,backward extension,bilateral (left and right) flexion,and left and right rotation,the L3/4 ROM of M2 model and L4/5 ROM of M3 model increased,while the L3/4 and L4/5 ROM of M4 and M5 models significantly decreased compared with those of M1 model.Under all motion modes,the L4 superior endplate in M2 model and the L5 superior endplate in M3 model showed the maximum peak von Mises stress,and the peak von Mises stresses of L4 and L5 superior endplates in M4 and M5 models were close.The L3/4 cage in M2 model and the L4/5 cage in M3 model showcased the largest peak von Mises stress,and the peak von Mises stresses of cages in M4 and M5 models were close.The peak stresses of internal fixation in M2-M5 models were close.Conclusion Four-screw fixation can replace 6-screw fixation in the OLIF surgery for treating two-level degenerative lumbar diseases.

Uncharted Territories: Dynamic Hip Screw Migration Into the Pelvis Requiring Laparotomy.

Hip fractures are common in patients with poor bone quality and are seen to affect the elderly and frail population. We report a case of implant failure after fixing an unstable intertrochanteric fracture with a dynamic hip screw (DHS). The patient presented with a DHS that had migrated into the pelvis approximately six months after surgery. Plain radiographs showed migration of the DHS through the acetabulum and into the pelvis. Migration of DHS into the pelvis is an extremely rare complication and has only been reported a few times. A 71-year-old man presented with a fall and confusion. The patient reported having a fall but could not recall the exact events. Past medical history included Alzheimer's dementia, osteoporosis, left total hip replacement, right DHS, peripheral neuropathy, and recurrent falls. He had undergone reduction and fixation of a right intertrochanteric fracture with DHS implant via direct lateral approach six months before hospital admission. On examination, he had right-sided hip pain and was unable to straighten leg raise. His abdomen was soft and non-tender, with no distension or palpable masses. Neurovascular status was normal, and no signs of infection were detected. On the anteroposterior radiograph, the implant seemed to have migrated through the acetabulum and into the abdomen. A CT of the abdomen and pelvis was performed to identify any visceral injuries (negative) and for surgical planning. The patient underwent a midline laparotomy to remove the implant. Although the exact reason for the implant failure is unknown, the migration of an unbroken hip screw into the abdomen and pelvis requiring laparotomy has not been reported in literature.

Screw placement through a higher medial portal provides better initial stability in arthroscopic ACL tibial avulsion fracture fixation: a finite element analysis.

OBJECTIVE: The objective of this study was to investigate the initial stability of different screw placements in arthroscopic anterior cruciate ligament (ACL) tibial avulsion fracture fixation. METHODS: A three-dimensional knee model at 90° flexion was utilized to simulate type III ACL tibial avulsion fracture and arthroscopic screw fixation through different portals, namely the central transpatellar tendon portal (CTP), anterolateral portal (ALP), anteromedial portal (AMP), lateral parapatellar portal (LPP), medial parapatellar portal (MPP), lateral suprapatellar portal (LSP), medial suprapatellar portal (MSP). A shear force of 450 N was applied to the finite element models at 30° flexion to simulate the failure condition. The displacement of the bony fragment and the volume of the bone above 25,000 µ-strain (damaged bone volume) were calculated around the screw path. RESULTS: When the screw was implanted through CTP, the displacement of the bony fragment reached the maximum displacement which was 1.10 mm and the maximum damaged bone volume around the screw path was 148.70 mm3. On the other hand, the minimum displacement of the bony fragment was 0.45 mm when the screw was implanted through LSP and MSP. The minimum damaged bone volume was 14.54 mm3 around the screw path when the screw was implanted through MSP. CONCLUSION: Screws implanted through a higher medial portal generated less displacement of the bony fragment and a minimum detrimental strain around the screw path. The findings are clinically relevant as they provide biomechanical evidence on optimizing screw placement in arthroscopic ACL tibial avulsion fracture fixation.

Conservative or operative therapy in patients with a fragility fracture of the pelvis: study protocol for a prospective, randomized controlled trial.

BACKGROUND: The incidence of fragility fractures of the pelvis is rising. Whereas the treatment for FFP type I, III, and IV is clear, the optimal treatment for FFP type II remains a topic of discussion. Traditionally these fractures have been treated conservatively. However, there is a shift toward early surgical stabilization with percutaneous screw fixation to reduce pain and promote mobility in an already frail patient population. High-quality evidence, however, is lacking. Therefore, a randomized clinical trial was designed to compare conservative management to early percutaneous screw fixation in patients with type II fragility fractures. METHODS: This is a monocenter randomized controlled trial. All patients with a FFP type II are screened for inclusion. After obtaining informed consent, patients are randomized between conservative management and surgical stabilization. Conservative management consists of early mobilization under guidance of physiotherapy and analgesics. Patients randomized for surgical treatment are operated on within 72 h using percutaneous screw fixation. The primary endpoint is mobility measured by the DEMMI score. Secondary endpoints are other dimensions of mobility, pain levels, quality of life, mortality, and morbidity. The total follow-up is 1 year. The required sample size is 68. DISCUSSION: The present study aims to give certainty on the potential benefit of surgical treatment. Current literature on this topic remains unclear. According to the volume of FFP at the study hospital, we assume that the number of patients needed for this study is gathered within 2 years. TRIAL REGISTRATION: ClinicalTrials.gov NCT04744350. Registered on February 8, 2021.

Evaluating three internal fixation techniques for Pauwels III femoral neck fractures via finite element analysis.

The selection of implants for fixing unstable femoral neck fractures (FNF) remains contentious. This study employs finite element analysis to examine the biomechanics of treating Pauwels type III femoral neck fractures using cannulated compression screws (3CS), biplane double-supported screw fixation (BDSF), and the femoral neck system (FNS). A three-dimensional model of the proximal femur was developed using computed tomography scans. Fracture models of the femoral neck were created with 3CS, BDSF, and FNS fixations. Von Mises stress on the proximal femur, fracture ends, internal fixators, and model displacements were assessed and compared across the three fixation methods (3CS, BDSF, and FNS) during the heel strike of normal walking. The maximum Von Mises stress in the proximal fragment was significantly higher with 3CS fixation compared to BDSF and FNS fixations (120.45 MPa vs. 82.44 MPa and 84.54 MPa, respectively). Regarding Von Mises stress distribution at the fracture ends, the highest stress in the 3CS group was 57.32 MPa, while BDSF and FNS groups showed 51.39 MPa and 49.23 MPa, respectively. Concerning implant stress, the FNS model exhibited greater Von Mises stress compared to the 3CS and BDSF models (236.67 MPa vs. 134.86 MPa and 140.69 MPa, respectively). Moreover, BDSF displayed slightly lower total displacement than 3CS fixation (7.19 mm vs. 7.66 mm), but slightly higher displacement than FNS (7.19 mm vs. 7.03 mm). This study concludes that BDSF outperforms 3CS fixation in terms of biomechanical efficacy and demonstrates similar performance to the FNS approach. As a result, BDSF stands as a dependable alternative for treating Pauwels type III femoral neck fractures.

A new technique for percutaneous screw fixation for treating FFP IIIa and IIIb fragility fractures of the pelvis.

To determine the presence of a consistent osseous corridor from the lateral-posterior aspect of the anterior inferior iliac spine to the sacral wing that could be used for safe trans percutaneous screw fixation for pelvic fragility fractures of the iliac wing and fracture dislocations of the sacroiliac joint (FFP types IIIa and IIIb). Computed tomography (CT) scans were obtained from 100 patients and imported to Mimics software for 3D reconstruction. Then, a cylinder was drawn to imitate the modified LC-II screw and adjusted to a maximum radius and length to obtain the feasible region. Thirteen parameters of the osseous corridor of the modified LC-II screw were measured. Differences between sex groups were compared, and significant statistical correlations were carefully studied to determine potentially important clinical relationships. The records of patients with FFP type IIIa and IIIb fragility fractures of the pelvis were extracted from our hospital. Patients who underwent modified LC-II screw fixation, LC-II screw fixation or reconstruction plate fixation were included. Patients' operative characteristics and complications were recorded at follow-up. Fracture reduction quality was assessed using the Matta standard. Functional outcomes were evaluated using the Majeed grading system. The mean maximum diameters of the osseous corridors of the modified LC-II screw in males and females were 12.73 and 10.83 mm, respectively. The mean maximum lengths of the osseous corridors of the modified LC-II screw in males and females were 96.37 and 93.37 mm, respectively. In the treatment of patients with FFP IIIa and FFP IIIb fractures, the group of treatment by the modified LC-II screws fixation was shown significantly shorter operative time and fewer intraoperative blood loss in comparison to that by the reconstruction plates. In the present study, all the males and females had a complete osseous corridor of the modified LC-II screw. The clinical results of the patients who were treated with modified LC-II screw fixation suggest that the novel method has a good preliminary outcome.

Should a low starting point be abandoned for cannulated screw fixation of femoral neck fractures?

A validated femoral neck fracture model stabilized with three inverted cannulated screws was used to consider different intraoperative scenarios when the inferior screw hole is inadvertently started too inferiorly. These scenarios were to: (1) abandon the misplaced inferior screw hole and restart this hole more proximally, or (2) accept the mispositioned placement of the inferior screw and insert the remaining superior screws parallel or convergent to the inferior screw. Utilizing the second option and accepting the errant hole was associated with the greatest interfragmentary motion and stresses in the bone and hardware. In contrast, the first option created an improved mechanical environment for healing.

Surgical management of tibial eminence avulsion fractures: a systematic review and meta-analysis.

PURPOSE: The ideal surgical management for tibial eminence avulsion fractures remains controversial with varying approach, methods of fixation and post-operative regimes reported throughout literature. The current systematic review and meta-analysis aims to compare between the different approaches, methods of fixation and post-operative regimes for tibial eminence fractures. METHODS: The systematic review was conducted according to PRISMA guidelines. A search was conducted using PubMed, MEDLINE and CINAHL databases. The keywords used were "anterior cruciate ligament", "tibial spine" or "tibial eminence" and "fracture" or "avulsion". All original human studies that reported the surgical outcomes of tibial eminence fractures were included. Individual patient data meta-analysis was performed. RESULTS: 48 studies with 1367 patients were included. Arthroscopic fixation resulted in significantly greater stability in terms of anterior drawer test (p = 0.018) and Lachman's test (p = 0.042), as compared to open fixation, though there was no significant difference for pivot shift test. There was no significant difference identified in functional scores and activity, including Lysholm score, IKDC subjective score, Tegner score and return to sports. Suture fixation had significantly increased stability compared to screw fixation, in terms of anterior drawer test (p = 0.001) and Lachman's test (p = 0.001), though no significant difference was identified for pivot shift test. Significantly better subjective scores and return to activity were also noted for suture fixation, in terms of Lysholm score (p = 0.008), IKDC subjective score (p = 0.001) and Tegner score (p = 0.001), though no significant difference was identified for return to sports. CONCLUSION: Arthroscopic and suture fixation had significantly superior outcomes when compared to open and screw fixation. Arthroscopic fixation resulted in significantly improved stability of the knee as compared to open fixation, though no significant difference was identified in terms of functional knee scores and return to activity. Suture fixation resulted in significantly improved stability of the knee and functional knee screws as compared to screw fixation.