Bicortical Fixation Research Articles

Bicortical Compression and Construct Stability With Variable Pitch Locking Screws in Cadaveric Specimens.

A variable pitch locking screw is intended to provide interfragmentary compression combined with fixed angle stability of locking plate constructs. The objective of this study was to compare variable pitch locking screws (3.5-mm KreuLock Ti locking compression screws, Arthrex Inc., Naples, FL) with standard locking screws (from the same manufacturer) in bicortical fixation scenarios in cadaver bone by assessing (1) interfragmentary compression and plate-bone compression and (2) construct biomechanical stability. Nine matched pairs of fresh-frozen cadaveric specimens with an average age of 67.2 years (range, 37-83) were used. Interfragmentary compression and plate-bone compression associated with insertion of single bicortical screws were compared between the variable pitch and standard locking screws at increasing levels of torque. The specimens tested were distal tibiae having a simulated longitudinal fracture. Additionally, fibulae were osteotomized to create a stable longitudinal fracture pattern and were fixed with a 5-screw plate construct with either all variable pitch or all standard locking screws. One of the 5 screws was placed across the osteotomy without lagging. Fibulae were tested cyclically with axial with torsional loading to compare displacements, rotation, and loads at failure or tested in 4-point bending to compare construct stiffness and maximum force to failure. Interfragmentary and plate-bone compression forces in the distal tibia model varied across specimens but were significantly higher with variable pitch locking screws compared with standard locking screws [512 N (SD = 324 N) vs. 79 N (SD = 64 N), P = 0.002, and 242 N (SD = 119 N) vs. 104 N (SD = 123 N), P = 0.028, respectively]. In cyclic loading of fibula constructs, no significant differences were detected in construct axial displacement or angular displacement (P > 0.05). In 4-point bending, no differences were detected in maximum force or bending stiffness (P > 0.05). Variable pitch locking screws produced interfragmentary compression between cortices and plate-bone compression that was greater than that produced by standard locking screws. In a stable bicortical fibula fixation scenario under external loading, the stability of variable pitch locking screw constructs was similar to constructs with standard locking screws.

Clinical and radiological evaluation of the Bristow–Latarjet procedure in patients with 30 or more years of follow-up

BackgroundThe Bristow-Latarjet surgery is the procedure most performed for recurrent anterior shoulder dislocation. There are few studies with a follow-up of more than 20 years. Because it is a nonanatomical technique, there is interest in knowing the clinical and radiological results and the rates of complications in the long term. MethodsWe performed a retrospective case series study. Patients with recurrent anterior dislocation of the shoulder who underwent the Bristow-Latarjet procedure were included and followed-up clinically for at least 30 years. We evaluated clinical scores - the Rowe, Western Ontario Shoulder Instability (WOSI), Single Assessment Numeric Evaluation (SANE), visual analog scale (VAS) – as well as clinical outcomes: the relapse (dislocation or subluxation) and seizure. Screw and graft positioning were assessed by computed tomography (CT), the degree of arthropathy by radiography, and subscapularis fatty degeneration as rotator cuff tears by magnetic resonance imaging (MRI). Both clinical scores and imaging were obtained at 30 years of surgery. ResultsTwenty-seven patients (30 shoulders) were evaluated, with a mean follow-up of 35±4.5 years. The scores obtained were 88.28±15.9 by Rowe, 208±244.2 by the WOSI examination, 92.5%±10.4% by the SANE and 0.45±1.3 by the VAS. The recurrence rate was 13.3%, with all patients presenting subluxations and no new dislocations. All grafts were positioned below the glenoid equator. In 82.4% of the cases, the grafts were aligned with the articular surface, 5.9% were medially deviated, and 11.8% were laterally deviated. Consolidation occurred in 76.5% of the cases. The screws presented bicortical fixation in 76.5% of the shoulders and inclination in the axial plane of less than 15° in 64.7%. A total of 58.8% of the cases presented with glenohumeral arthropathy, and 75% of the MRIs showed the absence of fatty degeneration. ConclusionBristow–Latarjet surgery demonstrates excellent clinical results in most patients after 30 years of follow-up. The recurrence rate is low, as is the complication rate. Glenohumeral arthropathy occurs in most patients without significant clinical repercussions.

Clinical study on freehand of bicortical sacral screw fixation with the assistance of torque measurement device

BackgroundSacral screw loosening is a typical complication after internal fixation surgery through the vertebral arch system. Bicortical fixation can successfully prevent screw loosening, and how improving the rate of bicortical fixation is a challenging clinical investigation.ObjectiveTo investigate the feasibility of improving the double corticality of sacral screws and the optimal fixation depth to achieve double cortical fixation by combining the torque measurement method with bare hands.MethodsNinety-seven cases of posterior lumbar internal fixation with pedicle root system were included in this study. Based on the tactile feedback of the surgeon indicating the expected penetration of the screw into the contralateral cortex of the sacrum, the screws were further rotated by 180°, 360°, or 720°, categorized into the bicortical 180° group, bicortical 360° group, and bicortical 720° group, respectively. Intraoperatively, the torque during screw insertion was recorded. Postoperatively, the rate of double-cortex engagement was evaluated at 7 days, and screw loosening was assessed at 1 year follow-up.ResultsThe bicortical rates of the 180° group, 360° group, and 720° group were 66.13%, 91.18% and 93.75%, respectively. There were statistically significant differences between the 180° group and both the 360° and 720° groups (P < 0.05). However, there was no statistically significant difference between the 360° group and the 720° group (P > 0.05).The rates of loosening of sacral screws in the 180° group, 360° group, and 720° group were 20.97%, 7.35% and 7.81%, respectively. There were statistically significant differences between the 180° group and both the 360° and 720° groups (P < 0.05). However, there was no statistically significant difference between the 360° group and the 720° group (P > 0.05). The bicortical 360° group achieved a relatively satisfactory rate of dual cortical purchase while maintaining a lower rate of screw loosening.ConclusionManual insertion of sacral screws with the assistance of a torque measurement device can achieve a relatively satisfactory dual cortical purchase rate while reducing patient hospitalization costs.

Four-screw compression plate fixation for diaphyseal humerus fractures.

While many humeral shaft fractures can be successfully treated with nonoperative management, compression plating techniques using at least three or four screws on either side of the fracture are the current gold standard. We hypothesized that a less rigid construct using compression with only two screws on either side of the fracture can provide adequate strength for uneventful fracture union. This is a retrospective review of all the patients who underwent open reduction and compression plate fixation for acute diaphyseal humerus fractures (ADHFs) at an academic Level-1 urban trauma center between 2018 and 2023. Patients treated with compression plating using only two screws and three or four plate-holes on either side of the fracture (Group 1) were matched one-to-one with patients treated using the conventional number of screws (three or more on either side of the fracture - Group 2). The incidence of nonunion/malunion, infection, and implant failure was compared among the two groups. There were eleven matched patients in both groups. The nonunion, infection complications, and hardware failure rates were 0% and 9.1% for the control group (Group 2) and four-screw group (Group 1) respectively. This difference was not statistically significant (p = 1.00). Although convention dictates the use of six or more bicortical screws (at least three bicortical screws on each side of the fracture), four-screw bicortical fixation may be a feasible option for ADHFs treated with large fragment compression plating techniques.

Treatment of Periprosthetic Hip Fractures Vancouver B1 and C: The Significance of Bicortical Fixation. A Bicentric Study Comparing Two Osteosynthesis Systems.

INTRODUCTION The incidence of periprosthetic fractures (PFFs) is estimated to range from 0.1% to 4.1%1, due to the increasing prevalence of joint arthroplasties, coupled with an aging population. Numerous risk factors, including advanced age (>80 years), female gender, implant type, prior diagnoses of osteonecrosis and rheumatoid arthritis, revision surgery, aseptic stem mobilization, and the use of non-cemented stems, have been identified. Survivors of periprosthetic fractures often experience functional deterioration, facing a fourfold higher risk of hospitalization for postoperative complications compared to patients undergoing primary implantation, especially in the first postoperative year. MATERIALS AND METHODS Between 2018 and 2022, at the Maggiore Hospitals in Bologna and the San Matteo Policlinic in Pavia, we performed osteosynthesis on 84 patients with periprosthetic fractures of Vancouver type B1 or C. In 38 patients, we employed angular stable plates with the Zimmer Biomet NCB-PP® system. In 46 patients, we utilized INTRAUMA plates: DF distal femur and PFF proximal. Relevant postoperative follow-up outcomes considered included reintervention, infectious complications, radiographic healing, and functional recovery, with reference to changes in the Glasgow Outcome Scale (GOS) and the Harris Hip Score (HHS). All patients underwent clinical and radiographic evaluations during the follow-up period, averaging 28 months (range: 12-48 months), with a minimum follow-up duration of 12 months. RESULTS At the 4-month postoperative assessment, 71% of patients maintained their preoperative functional level, 19% experienced a 1-point GOS scale drop, and 10% died (GOS 5). The average HHS at 4 months was 80.2 points (range: 65-90). At the 6-month follow-up, 98.2% of patients achieved complete healing on radiographic examination. Only 1 patient (1.2%) developed a pseudoarthrosis site with synthesis device rupture. Only 1 patient (1.2%) required additional surgical treatment 2 years later due to the development of un aseptic perisynthetic fluid collection, while the remaining 5 patients (6%) who developed complications benefited from conservative treatment: 4 patients (3.6%) with infectious complications were treated with intravenous antibiotics. In the 2 patients (2.3%) with mobilization or rupture of synthesis devices, clinical and radiographic monitoring was opted for. 8 patients (10.7%) died: one 48 hours after the surgery, and the other 7 more than one month after the surgery. CONCLUSION Our clinical findings align with to existing scientific literature on periprosthetic fractures (B1 and C according to Vancouver classification). Moreover, good stability has been guaranteed at the radiological follow up by Zimmer Biomet NCB-PP® and INTRAUMA DF distal femur and PFF proximal plates. The locking construct allows for improved stability especially in osteoporotic bone.

The application of a dual-lead locking screw could enhance the reduction and fixation stability of the proximal humerus fractures: a biomechanical evaluation.

Bicortical screw fixation, which penetrates and fixes the near and far cortex of bone, has been conventionally used to achieve compressive fixation for fracture using screws. Open reduction and internal fixation using the locking plate are widely used for treating proximal humerus fractures. However, minimal contact between the bone and the locking plate can lead to an insufficient reduction. Theoretically, a dual-lead locking screw with different leads for the screw head and body could enhance the reduction and fixation stability of fragments in proximal humeral fractures without bicortical fixation, and achieve additional compression at the bone-plate-screw interface. This study assessed the insertion mechanics of the lead ratio of the dual-lead locking screw and its effect on the fixation stability of the proximal humerus fracture. A Multi-Fix® locking plating system composed of 3.5 mm locking screws and a locking plate was used to make a locked plating for Sawbone bone blocks and fourth-generation composite humeri. Two different types of Sawbone bone blocks were used to simulate the osteoporotic (10 PCF) and normal cancellous (20 PCF) bones. The lead of the screw head thread () was 0.8 mm, and that of the screw body () was 0.8, 1.25, 1.6, 2.0, and 2.4 mm, whose lead ratios () were 1.0, 1.56, 2.0, 2.5, and 3.0, respectively. The dual-lead locking screw elevated the compression between the locking plate and the bone. The elevation in the compression due to the dual-lead thread became weaker for the cancellous bone when the lead of the screw body was more than twice that of the screw head. The plate/humerus compression with strong bone quality withstood higher dual-lead-driven compression. A dual-lead locking screw of () is recommended for maximum rotational stability for the locked humerus plating. The screws with over () have no advantage in terms of the failure torque and maximum torsional deformation. Any locking dual-lead screw with a body thread lead of <1.6 mm () can be used without the risk of bone crush when surgeons require additional compression to the locked cancellous bone plating.

Mid-term results of a cementless hip stem in femoral revision: how much diaphyseal press-fit do we need?

The aim of this retrospective study was to analyze the clinical and functional outcome of a modular tapered revision hip stem after mid-term follow-up with a special focus on the length of the distal bicortical fixation of the cementless hip stem. Follow-up examination was carried out for all patients with implantation of the Prevision hip stem between 2014 and 2019 to collect demographic, functional, and radiographic data. 44 patients with stem in situ were examined, and 61 patients could be included in the Kaplan-Meier survival analysis. Oxford's hip score was 37.3 at the mean follow-up of 4.0years. Two hip stem revisions were performed due to periprosthetic infection, which resulted in a hip stem survival rate of 96.7% (CI: 87.4-99.1%) at the final follow-up of 7.5years. No aseptic hip stem revision was required. The length of bicortical distal fixation was in the interquartile range of 6.8 to 9.0cm, which was associated with good bone healing and a low rate of subsidence (4.5%). Implant-associated complications were observed in 10 cases (21.7%). The modular revision hip stem provides promising results at medium-term follow-up, with satisfactory clinical and functional outcomes comparable to other modular revision hip stems. The presented length of bicortical distal fixation shows the practice of the study center and was associated with good implant survival, bone healing and radiological results. Clinicaltrials.gov registration: NCT04833634 registered on April 6, 2021.

Unicortical versus bicortical plate fixation for midshaft clavicular fractures

BackgroundThe aim of this study was to compare the functional and radiological outcomes of unicortical vs bicortical fixation in patients with midshaft clavicular fractures who were treated using pre-contoured locking plates. MethodsWe performed a prospective multicenter study of 45 individuals who underwent open reduction and internal fixation of midshaft clavicular fractures with precontoured locking plates between March 2017 and December 2019. Twenty-five patients were treated with bicortical screws and 20 patients with unicortical screws. Functional outcomes were assessed at 6 months and 12 months after surgery using the Constant score, the 11-item version of the Disabilities of Arm, Shoulder and Hand (Quick- DASH) score and the Single Assessment Numeric Evaluation (SANE) score. Pain was evaluated using a visual analog scale (VAS). The rate of return to work and sports was also recorded. Radiologic evaluation was obtained in the immediate postoperative day, monthly until fracture consolidation, at 6 months and 12 months. All intraoperative and postoperative complications were documented. ResultsAt both 6 and 12 months, the follow-up rates were 100%, and the mean age was 28.5 years (range, 20 to 45 years). The mean postoperative Constant score, Quick DASH, and SANE score at 12 months were 93.5 (±6), 2.3 (±3), and 92% (±7), respectively. There were no significant differences in the functional scores between the groups neither at 6 months nor at 12 months. Of the 30 active workers, 97% were able to return to their previous working routine and from the 25 patients who practiced sports before the injury,92% returned to sports all at the same level. All the fractures healed in both groups. There were 6 complications (13%). ConclusionIn young, active patients with displaced midshaft clavicular fractures, both unicortical and bicortical locked plates achieved 100% bone consolidation, with excellent functional outcomes and a low rate of complications without significant differences between the groups. Therefore, locked plates with unicortical fixation could be a very good alternative for the management of young patients with midshaft clavicular fractures, potentially avoiding severe neurovascular complications. Level of evidenceProspective comparative (Level II)

Risk of Neurovascular Injury during Screw Fixation of Tibial Tubercle Fractures in Pediatric and Adolescent Patients.

Objective To review knee magnetic resonance imaging (MRI) scans for the analysis of the location of neurovascular structures (NVSs), and to define the risk of bicortical fixation. Methods Distances between the posterior cortex and the popliteal NVSs were measured on the MRI scans of 45 adolescents (50 knees) at 3 levels (C1: center of the proximal tibial epiphysis; C2: 10 mm distal to the physis; and C3: 20 mm distal to the physis). The NVSs located between 5 mm and 10 mm from the incision were considered in a zone of moderate risk for damage, while those less than 5 mm from the incision were considered in a zone of high risk for damage, and those more than 10 mm from the incision were considered to be in a zone of low risk for damage. The independent Student t -test was used for the comparison of the NVS distance 0with gender, skeletal maturity, and the tibial tubercle-trochlear groove (TT-TG) distance. Values of p < 0.05 were regarded as statistically significant. Results The path of the C1 screw posed an increased risk of damage to the popliteal artery and vein compared with other screw paths ( p < 0.001). The popliteal artery has a high risk of damage at the level of C1 (4.2 ± 2.2mm), and a moderate risk at C2 (9.6 ± 2.4mm), and the popliteal vein has a moderate risk at C1 (6.0 ± 2.7 mm), and a low risk at C2 and C3 (10.8 ± 3.1mm, and 12.05 ± 3.1mm respectively). The C3 position presented the lowest risk of damage to these structures ( p < 0.001). The distance between the posterior tibial cortex and the posterior tibial nerve was < 15 mm at the 3 levels analyzed (C1: 11.0 ± 3.7 mm; C2: 13.1 ± 3.8 mm; and C3: 13 ± 3.9 mm). Conclusions The present study clarifies that the popliteal vessels are at risk of injury during tibial tubercle screw fixation, particularly when drilling the proximal tibial epiphysis. Monocortical drilling and screw fixation are recommended for the surgical treatment of tibial tubercle fractures. Level of Evidence III Diagnostic study.

The biomechanical state of the thoracolumbar junction with various options of transpedicular fixation under flexion load

Introduction. Morphological and biomechanical features of the thoracolumbar junction determine the large number of cases of traumatic bone injuries. Reconstructive and stabilizing surgeries performed in this area, due to the significant load on both the elements of hardware and bony structures, require high reliability of fixation. Objective. To study the stress-strain state of the model of the thoracolumbar section of the spine after the Th12-L1 vertebrae resection with various options of transpedicular fixation under the influence of flexion load. Materials and methods. The stress-strain state of the mathematical finite-element model of the thoracolumbar section of the human spine under the influence of flexion load was studied. The model simulated the condition after surgery for a significant traumatic lesion of the thoracolumbar junction with laminectomy, facetectomy, and corpectomy of the Th12 and L1 vertebrae. Four variants of transpedicular fixation were studied (using short or long bicortical fixation screws, two crosslinks and without them). Control points of the model characterizing the load distribution both in bony structures and on metal elements of fusion and body replacement systems were studied. Results. Crosslinks have the greatest effect on reducing the level of stress both in the bony elements of the models and in the metal elements. When comparing the length of the screws, the use of monocortical screws was determined to have minor biomechanical advantages. The stress analysis of the area of the screw entry into the pedicle of the arch of the fixed vertebrae (clinically significant zone) revealed that in the model with short screws and without crosslinks, the stress for the vertebrae Th10, Th11, L2 and L3 is 5.0, 1.9, 7.8 and 13.6 MPa, respectively, while the presence of crosslinks reduces the corresponding values to 4.6, 1.9, 7.3 and 12.7 MPa. In models with bicortical screws, the corresponding values are 5.1, 2.3, 10.2, and 12.7 MPa in the absence of crosslinks and 4.7, 1.8, 9.9, and 12.2 MPa with the presence. A similar trend is observed in other control points. When comparing the results with the compression load in the models studied earlier, it was established that flexion causes an increase in the stress of the models with monocortical screws by an average of 33.7%, with bicortical screws by 39.6%. Conclusions. In case of flexion load, the use of crosslinks makes it possible to reduce the level of stress in all control points of the models, regardless of the length of the used transpedicular screws, while the length of the screws does not have a fundamental effect on the stress distribution.

Distal Biceps Tendon Reconstruction with Achilles Tendon Allograft: A Case-Series

Background: Chronic, complete ruptures of the distal biceps tendon are often difficult to surgically repair due to significant fibrosis and retraction. The use of a graft is recommended, with recent literature suggesting that an Achilles tendon allograft leads to superior clinical outcomes. The purpose of this study is to present the surgical technique and retrospectively review the clinical outcomes of a distal biceps reconstruction technique that utilizes an Achilles tendon allograft with an Endobutton bicortical fixation system through a single S-shaped incision. Methods: Seven male patients and eight cases of distal biceps reconstruction with Achilles tendon allograft were identified between January 2017 and March 2022. The mean age was 48.3 ± 8.9 years with a mean time from initial injury to surgery of 6.1 ± 3.8 months. Charts were retrospectively reviewed for patient demographics, procedural technique, preoperative and postoperative evaluation, and complications. Results: The cohort had a mean follow-up of 4.6 ± 2.0 months (range, 1.4-8.2). At the final office visit, full range of motion had returned for all patients except one, who had a persistent 10° extension deficit. Flexion strength had returned to equal preoperative and preinjury gross strength out of 5 (4.7 ± 0.5 preoperatively vs. 4.4 ± 0.5 postoperatively) and supination improved from preoperative strength (2.2 ± 1.1 preoperatively vs. 3.6 ± 1.2 postoperatively). Four out of eight cases resulted in a new neuropraxia identified in postoperative care: two lateral antebrachial cutaneous nerves, one superficial branch of radial nerve, and one ulnar nerve, with insufficient follow-up duration to determine resolution. One patient reported excessive scar formation; otherwise, there were no major complications. Conclusion: Reconstruction of the distal biceps tendon using an Achilles tendon allograft is a technically challenging, yet effective approach for the treatment of complete distal biceps tendon ruptures that are chronic in nature, resulting in an improvement in preoperative disability with few postoperative complications.

Biomechanical evaluation of position and bicortical fixation of anterior lateral vertebral screws in a porcine model

Although an anterior approach with anterior lateral screw fixation has been developed for stabilizing the thoracolumbar spine clinically, screw loosening still occurs. In this novel in vitro study, we attempted to elucidate the optimal screw position in the lateral lumbar vertebra and the effect of bicortical fixation. A total of 72 fresh-frozen lumbar vertebrae from L1–6 were harvested from 12 mature pigs and randomly assigned to two modalities: bicortical fixation (n = 36) and unicortical fixation (n = 36). Six groups of screw positions in the lateral vertebral body in each modality were designated as central-anterior, central-middle, central-posterior, lower-anterior, lower-middle, and lower- posterior; 6 specimens were used in each group. The correlations between screw fixation modalities, screw positions and axial pullout strength were analyzed. An appropriate screw trajectory and insertional depth were confirmed using axial and sagittal X-ray imaging prior to pullout testing. In both bicortical and unicortical fixation modalities, the screw pullout force was significantly higher in the posterior or middle position than in the anterior position (p < 0.05), and there was no significant differences between the central and lower positions. The maximal pullout forces from the same screw positions in unicortical fixation modalities were all significantly lower, decreases that ranged from 32.7 to 74%, than those in bicortical fixation modalities. Our study using porcine vertebrae showed that screws in the middle or posterior position of the lateral vertebral body had a higher pullout performance than those in the anterior position. Posteriorly positioned lateral vertebral screws with unicortical fixation provided better stability than anteriorly positioned screws with bicortical fixation.

Biomechanical properties of bicortical and monocortical plate fixation for rib fractures in the adolescent human rib fracture model

Purpose The technical advancement of surgical stabilization of ribs often prevents the surgeons from fixation, despite the procedure`s documented improved outcomes. The aim of this study was to evaluate a less invasive approach involving a simplified monocortical rib fixation technique. Methods Eighteen frozen human ribs obtained intraoperatively from young individuals aged 13-18 were employed for this study. First, the ribs were fractured under three-point bending, with their intrathoracic side put under tensile stress. Following this, the ChM 4.0 rib fixation system was utilized. The specimens were categorized into two groups: bicortical fixation (n=9), monocortical fixation (n=9). Subsequently, bicortical and monocortical fixation groups underwent dynamic testing over 400,000 cycles under combined sinusoidal tensile bending and torsional loading (2 N-5 N at 3Hz). In the final stage, all samples were subjected to a destructive load to failure. Results Our analysis revealed that the fixation method did not demonstrate statistically significant differences in terms of preliminary bending stiffness (p=0.379). Similarly, undergoing a course of 400,000 cycles involving combined tensile and torsional loading did not constitute a statistically significant factor affecting the monocortical and the bicortical fixation groups (p=0.894). In the monocortical fixation group, all specimens failed due to screws pulled out from the bone. In contrast, all specimens in the bicortical fixation group exhibited failure attributed to fractures occurring just behind the plate. Nonetheless, the fixation method was not a significant factor affecting bending strength (p=0.863). Conclusions The monocortial fixation could be a reasonable option among younger populations with comparable stability of fixation.

Technique Tip: Bicortical Fixation of Medial Malleolus Fractures With 2.7 mm Screws

Bicortical fixation of medial malleolus fractures provides increased interfragmentary compression and resistance to pull out. Achieving bicortical fixation with two 3.5 mm screws can be challenging especially with smaller fractures. We present a simple technique where two 2.7 mm screws are utilized for fixation of medial malleolus fractures. Level of Evidence: Level V—expert opinion.

Distal Biceps Tendon Repair Using a Unicortical Button

Background: Distal biceps tendon ruptures occur most commonly in the dominant arm of men in their 4th through 6th decades of life. These injuries lead to a 30% reduction in flexion strength and 40% reduction in supination strength. Numerous methods exist for fixation of the distal biceps tendon, including bicortical endobutton, transosseous tunnels, suture anchors, and interference screws. We review the technique for using a unicortical button fixation method. Indications: Indications for surgical fixation of the distal biceps tendon include complete tendon ruptures, where a loss of elbow flexion and forearm supination strength of 30% and 40%, respectively, is not desired and partial tendon ruptures that have failed nonoperative treatment. Typically, nonoperative treatment of partial tendon ruptures is tried for a minimum of 3 months. Technique Description: We present the technique of repairing a distal biceps tendon rupture using a unicortical button. A 1-incision technique is utilized through a transverse incision approximately 3-4 cm distal to the elbow flexion crease. Onlay fixation of the distal biceps tendon to the radial tuberosity is achieved with a unicortical, or intramedullary, button. The postoperative protocol varies with surgeon but is similar to other fixation techniques. Results: Outcomes for primary repair of the distal biceps tendon are promising in the literature with both patient-reported outcomes and objective data showing good to excellent results. Bicortical button fixation has traditionally shown to be stiffer with a higher load to failure than other fixation techniques, including suture anchors, transosseous tunnels, and interference screws. The unicortical button has been shown to be statistically equivalent to the bicortical button, with similar cyclic loading and load to failure values. Discussion/Conclusion: The unicortical button technique for distal biceps repairs has the benefit of using a small footprint in the radial tuberosity, potentially decreasing the risk of heterotopic ossification, providing a safer avenue of obtaining anatomic placement and trajectory of repair, and decreasing the risk of posterior interosseous nerve injury. The unicortical button has been shown to have a similar strength profile to the bicortical button, which is higher than all other fixation techniques previously described in the literature.

The addition of cerclage wiring does not improve proximal bicortical fixation of locking plates for Type C periprosthetic fractures in synthetic humeri

BackgroundTreatment of proximal humerus periprosthetic fractures is challenging. It remains difficult to achieve robust fixation of the proximal fragment to the locking plate using cerclage wiring and/or unicortical screws. Use of polyaxial tangentially directed bicortical locking screws increases screw purchase, but it is unclear if this option provides robust fixation. This biomechanical study compares fixation of constructs using cerclage wires, bicortical locking screws, and a hybrid method utilizing both methods. MethodsUncemented humeral stems were implanted into synthetic humeri and Type C periprosthetic fractures were simulated with a 1 cm transverse osteotomy. Distal ends of locking plates were secured with bicortical non-locking screws. The proximal ends were supported by either isolated cerclage wires, polyaxial locking screws, or a hybrid combination of both (n = 6 for each group). A universal test frame was used for non-destructive torsion and cyclic axial compression tests. 3-D motion tracking was employed to determine stiffnesses and relative interfragmentary motions. FindingsIsolated screw constructs showed significantly increased resistance against torsional movement, bending, and shear, (p < 0.05) in comparison to cerclage constructs. The hybrid construct provided no significant changes in stability over the isolated screw construct. InterpretationAddition of cerclage wires in this synthetic bone model of Type C periprosthetic humerus fractures did not add significant stability to proximal bicortical locking plate fixation. Considering risks of tissue stripping and nerve injury, usage of cerclage wires in a similar clinical setting should be chosen carefully, especially when bicortical fixation around the prosthetic stem can be achieved.

Radial tuberosity anatomy in intramedullar repair of distal biceps tendon ruptures. A radiological study.

The aim of this study was to measure cortex thickness and medullar canal width of the bicipital tuberosity, to evaluate the accessibility of a intramedullar fixation device and the resistance to pullout strengths of the anterior cortex. The final objective was to determine the length of tendon ingrowth size that will be expected when using this surgical technique. A total of 144 computer tomography images of the proximal radius were used. Bone thickness of the anterior and posterior cortex and medullar canal size were measured. The possible ingrowth of the tendon was measured both for an anatomical and non- anatomical reinsertion. Statistical and concordance analyses of results were performed. The average width of the medullar canal was 8,7mm proximal, 7,9mm distal and 7,7mm at the tuberosity. The average posterior and anterior cortex measured respectively 2,5mm and 2,9mm proximal, 3,2mm and 3,2mm distal and 2,8mm and 1,9mm at the radial tuberosity. The possible non-anatomical ingrowth was 7,6 mm on average and the possible anatomical ingrowth was 7,6mm on average. The radial tuberosity anatomy can accommodate the new distal biceps fixation device. The anterior cortex on which the new device relies for support has a similar thickness as the posterior cortex used in bicortical fixation devices which may suggest similar resistance to pull-out strengths. The availability for intra-osseous fixation of the tendon stump may avoids tendon gapping. The intra-osseous length for the tendon stump surpassed reported tendon slippage during mobilization and active contraction of the distal biceps tendon.

Unicortical fixation does not compromise bony union in the Latarjet procedure

BackgroundFixation of the coracoid during the Latarjet procedure can be performed with either unicortical or bicortical fixation. There is no clear evidence that the number of cortices fixed affects graft union, but in vitro studies suggest bicortical fixation is desirable. The primary aim of the study was to retrospectively review the coracoid union rates in our Latarjet cohort who have undergone either unicortical or bicortical graft fixation.MethodsA retrospective review of Latarjet patients receiving bicortical or unicortical fixation was performed. The rate of coracoid graft union was assessed via radiographs and computed tomography scans at minimum 8 weeks postoperatively. Primary analysis for graft union was performed with Chi-squared and Fisher’s exact tests.ResultsA total of 184 patients were enrolled (82 bicortical, 102 unicortical) with 20 patients lost to follow-up. There was no significant difference between union rates of bicortical and unicortical groups (union rate: 94% bicortical, 98% unicortical, P = .25). There were no significant differences in rate of instability recurrence (P = .5) or other postoperative complications (P = .83) between the groups.DiscussionAt a minimum follow-up of 8 weeks, bicortical fixation was not shown to have a higher rate of union than unicortical fixation. Performing unicortical fixation is an acceptable practice without compromising bony graft union.

Determination of a neurologic safe zone for bicortical S1 pedicle screw placement

BACKGROUND CONTEXTLumbosacral fixation is commonly used for the management of lumbosacral instability. As the sacrum mainly consists of cancellous bone, bicortical fixation, in which the pedicle screw penetrates the anterior sacral cortex, can help increase the strength of fixation. However, this method carries a risk to the L5 nerves which lie anterior to the sacrum at this level. PURPOSEThe goal of this study is to determine a safe zone for the placement of S1 pedicle screws to decrease the likelihood of L5 nerve injury. STUDY DESIGNRetrospective imaging review. PATIENT SAMPLEThis study evaluated imaging data of patients who underwent lumbar spine magnetic resonance imaging (MRI) at our institute between September 1, 2020 and September 1, 2021. OUTCOME MEASUREST1-weighted axial MRIs were measured at the level of S1 pedicle screw placement. The space medial and lateral to the L5 nerve root on the anterior sacrum were measured and defined as safe zones. Additionally, the nerve width and sacral lengths were measured at this level. METHODSThe distribution of the measurements were evaluated to determine a medial and lateral safe zone, as well as the average nerve width at the level of S1 pedicle screw placement. Correlation analysis was performed to determine a relationship between safe zone sizes and sacral size. RESULTSA total of 400 MRIs were analyzed. The average medial safe zone measured was 32.8 mm (95% CI: 32.2–33.4) with no nerves lying within 22.3 mm of the midline sacrum. The average lateral safe zone measured was 17.7 mm (95% CI: 17.1–18.2), with no nerves within 5.3 mm of the lateral border of the sacrum. The average nerve root width was 6.2 mm (95% CI: 6.13–6.34). An increased sacral length was associated with a larger medial (p<.001) and lateral (p<.001) safe zone. CONCLUSIONSOur study revealed lateral and medial safe zones for the placement of S1 pedicle screws to avoid iatrogenic nerve injury in a retrospective cohort of 400 patients. There were no L5 nerve roots found within 22.3 mm of the sacrum's mid-axis or within 5.3 mm of the sacrum's anterolateral border. These defined safe zones can be used during pedicle screw planning and placement to decrease the risk of injury to the L5 nerve root.

LOQTEQ® VA Periprosthetic Plate-A New Concept for Bicortical Screw Fixation in Periprosthetic Fractures: A Technical Note.

Internal fixation using angle stable plates is the treatment standard in periprosthetic fractures around stable implants. To provide instant postoperative full weight-bearing, bicortical screw fixation is advisable but often surgically demanding. This work presents the first clinical results of the LOQTEQ® VA Periprosthetic Plate (aap Implantate AG, Berlin, Germany), a new plate system to simplify screw placement around implants. This plate system uses insertable hinges that allow for variable angle screw anchorage. Data of 26 patients with a mean age of 80 years and a mean follow-up of 13.9 months were retrospectively collected. Patients were clinically and radiologically examined. Bony union was achieved in 14 out of 15 patients with no signs of non-union or implant loosening. One patient, however, presented with implant failure. Clinical scores demonstrated acceptable results. Since the hinge plates are easy to apply, the first results are promising.