BACKGROUND: Pelvic ring fractures are becoming more common in the aging population and can prove to be fatal, having mortality rates between 10% and 16%. Stabilization of these fractures is challenging and often require immediate internal fixation. Therefore, it is necessary to have a biomechanical understanding of the different fixation techniques for pelvic ring fractures.
METHODS: A previously validated three-dimensional finite element model of the lumbar spine, pelvis, and femur was used for this study. A unilateral pelvic ring fracture was simulated by resecting the left side of the sacrum and pelvis. Five different fixation techniques were used to stabilize the fracture. A compressive follower load and pure moment was applied to compare different biomechanical parameters including range of motion (contralateral sacroiliac joint, L1-S1 segment, L5-S1 segment), and stresses (L5-S1 nucleus stresses, instrument stresses) between different fixation techniques.
RESULTS: Trans-iliac-trans-sacral screw fixation at S1 and S2 showed the highest stabilization for horizontal and vertical displacement at the sacral fracture site and reduction of contralateral sacroiliac joint for bending and flexion range of motion by 165% and 121%, respectively. DTSF (Double transiliac rod and screw fixation) model showed highest stabilization in horizontal displacement at the pubic rami fracture site, while the L5_PF_W_CC (L5-Ilium posterior screw fixation with cross connectors) and L5_PF_WO_CC (L5-Ilium posterior screw fixation without cross connectors) showed higher rod stresses, reduced L1-S1 (approximately 28%), and L5-S1 (approximately 90%) range of motion.
CONCLUSIONS: Longer sacral screw fixations were superior in stabilizing sacral and contralateral sacroiliac joint range of motion. Lumbopelvic fixations displayed a higher degree of stabilization in the horizontal displacement compared to vertical displacement of pubic rami fracture, while also indicating the highest rod stresses. When determining the surgical approach for pelvic ring fractures, patient-specific factors should be accounted for to weigh the advantages and disadvantages for each technique.

BACKGROUND: Despite modern fixation techniques, spinopelvic fixation failure (SPFF) after adult spinal deformity (ASD) surgery ranges from 4.5 to 38.0%, with approximately 50% requiring reoperation. Compared to other well-studied complications after ASD surgery, less is known about the incidence and predictors of SPFF.
OBJECTIVE: Given the high rates of SPFF and reoperation needed to treat it, the purpose of this systematic review and meta-analysis was to report the incidence and failure mechanisms of SPF after ASD surgery.
METHODS: The literature search was executed across four databases: Medline via PubMed and Ovid, SPORTDiscus via EBSCO, Cochrane Library via Wiley, and Scopus. Study inclusion criteria were patients undergoing ASD surgery with spinopelvic instrumentation, report rates of SPFF and type of failure mechanism, patients over 18 years of age, minimum 1-year follow-up, and cohort or case-control studies. From each study, we collected general demographic information (age, gender, and body mass index), primary/revision, type of ASD, and mode of failure (screw loosening, rod breakage, pseudarthrosis, screw failure, SI joint pain, screw protrusion, set plug dislodgment, and sacral fracture) and recorded the overall rate of SPF as well as failure rate for each type. For the assessment of failure rate, we required a minimum of 12 months follow-up with radiographic assessment.
RESULTS: Of 206 studies queried, 14 met inclusion criteria comprising 3570 ASD patients who underwent ASD surgery with pelvic instrumentation (mean age 65.5 ± 3.6 years). The mean SPFF rate was 22.1% (range 3-41%). Stratification for type of failure resulted in a mean SPFF rate of 23.3% for the pseudarthrosis group; 16.5% for the rod fracture group; 13.5% for the iliac screw loosening group; 7.3% for the SIJ pain group; 6.1% for the iliac screw group; 3.6% for the set plug dislodgement group; 1.1% for the sacral fracture group; and 1% for the iliac screw prominence group.
CONCLUSIONS: The aggregate rate of SPFF after ASD surgery is 22.1%. The most common mechanisms of failure were pseudarthrosis, rod fracture, and iliac screw loosening. Studies of SPFF remain heterogeneous, and a consistent definition of what constitutes SPFF is needed. This study may enable surgeons to provide patient specific constructs with pelvic fixation constructs to minimize this risk of failure.

Intramedullary K-wire (IMKW) fixation is one of the mainstays for surgically treating metacarpal shaft and neck fractures. However, there remains a lack of literature comparing outcomes of the various available surgical repair techniques in all indicated metacarpals. Therefore, we conducted a systematic review and meta-analysis to investigate the clinical advantages and drawbacks of IMKW compared with alternate fracture repair techniques. A comprehensive systematic literature review was performed to identify studies that compared clinical outcomes of IMKW to alternate metacarpal fixation modalities. Outcomes included Disabilities of the Arm, Shoulder, and Hand (DASH/ quick DASH) scores, grip strength, union rate, visual analog scale pain, operative time, and complications. A random-effects model was used to compare IMKW to the pooled effect of other fixation techniques. A total of 10 studies were included in our analysis, comprising 497 metacarpal fractures (220 shafts and 277 necks). IMKW fixation was identified as the control group in all studies. The pooled experimental group included plates, transverse K-wires (TKWs), interfragmentary screws (IFSs), and K-wire cross-pinning (CP). In treating metacarpal shaft fractures, IMKW showed significantly shorter operative time ( p  = 0.04; mean difference = - 13; 95% confidence interval = -26 to -0.64). No significant differences were observed in treating metacarpal neck fractures for disability, grip strength, healing rate, pain, operative time, or complication rate. This systematic review and meta-analysis found no difference in clinical outcomes among various surgical techniques for treating metacarpal shaft and neck fractures. Further high evidence studies are required that investigate the efficacy and safety of IFS, CP, TKW, and intramedullary screws versus IMKW for treating closed, unstable metacarpal fractures.

Ankle fractures are among the most common orthopaedic injuries. Operative management is performed in unstable ankle fracture patterns to restore the stability and native kinematics of the ankle mortise and minimize the risk of post-traumatic degenerative changes. In this study, we review current concepts in ankle fracture management, including posterior malleolus fixation, syndesmosis fixation, deltoid ligament repair, fibular nailing, and early weightbearing, from both a biomechanical and clinical perspective.

Pelvic limb fractures carry significant morbidity in avian patients, and although management options are well researched, published data on long-term complication rates and mortality outcomes are limited. Here, we present a cross-sectional study evaluating pelvic limb long bone fractures in companion psittacine birds presenting to an exotic-only veterinary hospital in the United Kingdom between 2005 and 2020, focusing on fixation techniques and long-term outcomes. Of the 60 cases that met the inclusion criteria, 22 separate species were represented, with an age range of 8 weeks to 25 years and an even distribution of sexes, among those that had been sexed. The majority of fractures (71.7%) were tibiotarsal; femoral (15%) and tarsometatarsal (13.3%) bones represented the other fracture sites. Several different fracture management methods were used, including external coaptation, surgery, or cage rest. Average time from fracture identification to healing was 33 days, with a median of 31 days and a range of 11-121 days. Satisfactory resolution of fracture repair was achieved in 85.5% (47/55) of cases that were able to be followed to conclusion. Complications were identified in 41.7% (25/60) of fractures of all pelvic long bones. Complications during fracture management were more common in cases treated with external coaptation. The most common complication reported was patient interference with bandages, splints, or both. This study provides an overview of pelvic limb long bone fracture management outcomes, which should prove useful for avian practitioners in clinical practice.

BACKGROUND: Unstable femoral neck fractures with medial calcar defects are difficult to manage. The optimal fixation methods for these fractures have been a subject of ongoing debate among orthopedic surgeons. In this study, three different fixation techniques for vertical, medial defected femoral neck fractures were compared.
METHODS: In this study, a biomechanical analysis was conducted to compare three fixation methods: cannulated screws (Group 1), cannulated screws combined with a medial buttress plate (Group 2), and intramedullary nails (Group 3). Synthetic composite bone models representing vertical collum femoris fractures with medial calcar defects were used. Each group consisted of seven specimens, and, to maintain consistency, a single surgeon performed the surgical procedure. Biomechanical testing involved subjecting the specimens to axial loading until failure, and the load to failure, stiffness, and displacement values were recorded. Normality was tested using the Shapiro-Wilk test. One-way ANOVA and Tukey\'s HSD post hoc test were used for comparisons.
RESULTS: The difference in the load to failure values was statistically significant among the groups, with Group 2 exhibiting the highest load to failure value, followed by Group 3 and Group 1. Stiffness values were significantly higher in Group 2 than in the other groups. Displacement values were not significantly different between the groups. Fracture and displacement patterns at the point of failure varied across the groups.
CONCLUSIONS: The results of this study indicate that fixation with a medial buttress plate in combination with cannulated screws provides additional biomechanical stability for vertical femoral neck fractures with medial calcar defects. Intramedullary nail fixation also demonstrated durable stability in these fractures. These findings can be used to better understand current management strategies for these challenging fractures to promote the identification of better evidence-based recommendations.

Talonavicular arthrodesis is associated with a rate of non-union that ranges from 3 % to 37 %. Various fixation devices have been reported for talonavicular arthrodesis including screws, staples, plates, K-wires and intraosseous fix systems, however there is no definitive gold standard. This systematic review aims to compare clinical outcomes between different fixation devices for talonavicular arthrodesis.
METHODS: MEDLINE, EMBASE, CENTRAL and Google Scholar were reviewed for studies reporting on outcomes of different fixation techniques for talonavicular arthrodesis indicated for osteoarthritis, inflammatory and post-traumatic arthritis from 1946 to 2021. The primary outcome measure was union rate. Secondary outcome measures included functional improvement, cost, quality of life and patient satisfaction.
RESULTS: 9 articles involving 141 cases of talonavicular arthrodesis were identified. Fusion rates were as follows: screw fixation (n = 75): 87.5 % to 100 %, staple fixation (n = 13): 100 %, intraosseous fix system (n = 16): 100 %, and K-wire fixation (n = 2): 100 %. One study utilised a dorsal locking plate with two supplemented compression screws (n = 9, fusion rate= 100 %) and two studies used a combination of screws with staples (n = 26, fusion rate= 96 %). 7 of 9 studies measured functional outcomes and pain relief with improvement demonstrated in all fixation techniques. Quality of life, satisfaction and cost were inadequately reported amongst the included studies. All studies were rated as serious risk of bias.
CONCLUSIONS: This systematic review consolidates the evidence for outcomes of different fixation techniques for TN arthrodesis, however a definitive judgement regarding the best fixation technique is unobtainable from current clinical evidence, due to lack of high-quality studies. With review of biomechanical studies and the limited clinical data, fixation with plate plus screw is most promising and would warrant further comparative study.
METHODS: IV.

Fractures of the acromion and the scapular spine are established complications of reverse shoulder arthroplasty (RSA), and when they occur, the continuous strain by the deltoid along the bony fragments makes healing difficult. Evidence on treatment specific outcomes is poor, making the definition of a gold standard fixation technique difficult. The purpose of this systematic review is to assess whether any particular fixation construct offers improved clinical and/or radiographic outcomes. A systematic review of the literature on fixation of acromial and scapular spine fractures following RSA was carried out based on the guidelines of PRISMA. The search was conducted on PubMed, Embase, OVID Medline, and CENTRAL databases with strict inclusion and exclusion criteria applied. Methodological quality assessment of each included study was done using the modified Coleman methodology score to asses MQOE. Selection of the studies, data extraction and methodological quality assessment was carried out by two of the authors independently. Only clinical studies reporting on fixation of the aforementioned fractures were considered. Fixation construct, fracture union and time to union, shoulder function and complications were investigated. Nine studies reported on fixation strategies for acromial and scapular spine fractures and were therefore included. The 18 reported results related to fractures in 17 patients; 1 was classified as a Levy Type I fracture, 10 as a Levy Type II fracture and the remaining 7 fractures were defined as Levy Type III. The most frequent fixation construct in type II scapular spine fractures was a single plate (used in 6 of the 10 cases), whereas dual platin was the most used fixation for Levy Type III fractures (5 out of 7). Radiographic union was reported in 15 out of 18 fractures, whereas 1 patient (6.7%) had a confirmed non-union of a Levy Type III scapular spine fracture, requiring revision fixation. There were 5 complications reported, with 2 patients undergoing removal of metal and 1 patient undergoing revision fixation. The Subjective Shoulder Value and Visual Analogue Scale pain score averaged 75% and 2.6 points, respectively. The absolute Constant Score and the ASES score averaged 48.2 and 78.3 points, respectively. With the available data, it is not possible to define a gold standard surgical fixation but it seems that even when fracture union can be achieved, functional outcomes are moderate and there is an increased complication rate. Future studies are required to establish a gold standard fixation technique.

Intraoperative proximal femoral fractures (IPFF) represent a rare but challenging complication of total hip arthroplasties. They usually occur as a longitudinal split. This pilot trial aimed to compare the biomechanical primary stability of different fixation techniques for IPFF. Standardised longitudinal medial split fractures of the proximal femur (type II, Modified Mallory Classification) were created in artificial osteoporotic and non-osteoporotic composite femora after implantation of a cementless femoral stem. Five different fixation techniques were compared: cerclage band, cerclage wiring with one or two wires, and lag screw fixation with one or two lag screws. A quasi-static loading protocol was applied and failure loads were evaluated. The observed median failure loads were 4192N (3982N - 5189N) for one cerclage band, 4450N (3577N - 4927N) for one cerclage wire, 5016N (4175N - 5685N) for two cerclage wires, 6085N (5000N - 8907N) for one lag screw, and 4774N (4509N - 8502N) for two lag screws. Due to the wide range of failure loads within the experimental groups, there were no observable differences between the groups. All fixation techniques provided sufficient primary stability in osteoporotic and non-osteoporotic composite bones. Further cadaveric studies with larger sample sizes may be needed to confirm the results presented here.

UNASSIGNED: This study aimed to define variations in radiological C1 and C2 measurements among Vietnamese subjects and to determine the feasibility of implementing C1-2 fixation techniques.
UNASSIGNED: From October 2017 to April 2018, 120 patients underwent thin slide computed tomography (CT) scans of the cervical spine, in our hospital. Various dimensions of the C1 and C2 were analyzed, using axial and sagittal reconstructions of CT images. Differences in characteristics between the two sides and between sexes were investigated, using Student\'s t-test, with significance at P < 0.05.
UNASSIGNED: The mean anteroposterior dimension and the transverse width of the C1 lateral mass were 19.7 ± 2.1 mm and 12.2 ± 1.7 mm, respectively. The mean angles of the screw, directed to the maximal medial, lateral, cranial, and caudal directions, were 36.6 ± 2.8°, 28.2 ± 3.0°, 49.6 ± 4.1°, and 26.4 ± 5.5°, respectively. The average isthmus height, internal height, and pedicle width of the C2 were 5.8 ± 1.0 mm, 4.8 ± 1.3 mm, and 5.0 ± 1.3 mm, respectively. No significant differences were observed for any parameters, between the left and right side of the C1 or C2 or between the two sexes.
UNASSIGNED: This study revealed that the morphology of the C1 and C2 did not differ between genders in the studied subjects, but morphologic variations exist between Vietnamese subjects and other populations. Pre-operative anatomy evaluations based on CT data are essential be performed for screw placement and trajectory planning to avoid neurovascular complications and to enhance the treatment outcome.