Plate Construct Research Articles

Biomechanical Performance of 4-Leg Sustained Dynamic Compression Staples in First Tarsometatarsal Arthrodesis.

This study investigates the biomechanical efficacy of new 4-leg Sustained Dynamic Compression (SDC) NiTiNOL staples, hypothesized to offer superior stability and resilience to loading before fusion completion, compared with conventional hardware. Twenty sawbones left full foot models were divided into 4 treatment groups: (1) 4-leg Inline Staple, (2) 4-leg Inline Staple + 2-leg Staple, (3) 4-leg Inline Staple + Screw, and (4) Plate + Screw. An osteotomy was performed to simulate a Lapidus procedure, and the respective fixation methods were applied. Mechanical testing was conducted using a servo-hydraulic testing machine to evaluate constructs' load, contact force, contact area, and plantar gap. The 4-leg Inline Staple + Screw group demonstrated significantly increased joint contact force, joint contact area, and decreased plantar gap compared with the Plate + Screw group, both before and after cyclic testing. All SDC-containing constructs exhibited post-cyclic joint contact areas that were 2.36×, 3.87×, and 5.49× greater than the post-cyclic plate + screw group. Most notably, the 4-leg Inline Staple + Screw group maintained a plantar gap of less than 3 mm throughout the testing, unlike other groups. The 4-leg Inline SDC Staple, particularly when combined with a static screw, demonstrated biomechanical superiority over traditional plate and screw constructs in Lapidus procedures. These findings suggest a promising avenue for enhanced post-operative stability, which could translate into quicker patient recovery, improved fusion rates, and potentially lower non-union rates. Further clinical trials are warranted to validate these biomechanical advantages in patient outcomes. Therapeutic, Level V: Bench Testing.

Removal of the Metaphyseal Screw From Tension Band Constructs After Hemiepiphysiodesis: High Rates of Physeal Tethering and Subsequent Implant Removal.

Removal of the metaphyseal screw from tension band plate constructs after correction of angular deformity in patients treated with hemiepiphysiodesis has been suggested as an alternative to removing the plate and both screws. While this has the potential benefit of easier implant removal and reinsertion in the event of rebound, there is debate in the literature regarding the benefits and risks of leaving the epiphyseal screw and plate in place. Patients treated with hemiepiphysiodesis at the distal femur and/or proximal tibia with tension band plates and screws who underwent subsequent removal of the metaphyseal screw after correction were included. Charts and radiographs were reviewed for the need for metaphyseal screw reinsertion, subsequent removal of deep implants, and evidence of physeal tethering. Tethering was defined as progressive overcorrection in the treated bone segment after removal of the metaphyseal screw with the mechanical axis moving one full mechanical axis zone or more. Patients with tethering were compared with those without. A total of 215 patients with 387 limbs treated met inclusion criteria. Of those, 175 patients were treated for idiopathic genu valgum, while 40 were treated for other conditions. Fifty-nine individuals (27%) underwent replacement of the metaphyseal screw for repeat angular correction. Fifty-one percent of patients underwent secondary procedures for reasons other than metaphyseal screw reinsertion (74 symptomatic implant removal, 7 elective implant removal, 29 due to tethering). There were 44 cases of tethering in 36 patients (17%). In cases of tethering, 7 patients were treated with observation, 11 with implant removal only, 16 with hemiepiphysiodesis on the opposite side, and 2 with osteotomy. Patients with tethering were significantly younger, more likely to be male, and more likely to have had the metaphyseal screw removed more than once (P < 0.05). Removal of only the metaphyseal screw after hemiepiphysiodesis has high rates of tethering and further surgery for iatrogenic deformity correction and implant removal. This technique is not recommended. Therapeutic Level III, case-control study.

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.

Biomechanical Evaluation of Suture Augmentation of Dorsal Locking Plate Fixation in Transverse Patella Fractures.

Adjunctive suture augmentation of patellar plate fixation has yet to be investigated. Our biomechanical study sought to evaluate whether suture augmentation improves dorsal patellar locking plate fixation. Our hypothesis was that suture augmentation would improve fixation of this construct. A transverse patella fracture in six matched cadaveric pairs was stabilized using a patellar locking plate with or without suture augmentation. Specimens were tested at 60° knee flexion with load placed through quadriceps. Cyclic loading followed by load to failure was done. Stiffness, deformation at peak, and nonrecoverable deformation were calculated. During cyclic loading, suture augmentation demonstrated a higher average stiffness throughout all loads. At the final cycle, deformation was markedly higher without suture augmentation. Average load to failure was higher with suture augmentation. Maximum load to failure occurred at 2500 N in both groups. Suture augmentation in a transverse patellar fracture model improved dorsal plate fixation, leading to less fracture displacement at the final load. Although suture augmentation demonstrated higher stiffness and lower deformation, these trends were not statistically significant. In both groups, plate fixation sustained very high loads, which reflects the fixation strength of the dorsal locking plate and screw construct in this fracture model.

Nail–Plate Constructs for Treating Distal Femur Fractures: A Systematic Review of Biomechanical Studies

The biomechanical efficacy of nail–plate constructs (NPCs) used in the treatment of traumatic distal femur fractures (DFFs) remains understudied compared to traditional approaches. This systematic review examines the biomechanical efficacy of NPCs compared to alternative approaches for the surgical fixation of DFFs to guide surgical decision-making and improve patient outcomes. This systematic review searched the PubMed, CINAHL, MEDLINE, Web of Science, and SPORT Discus databases from inception until 24 January 2024. Inclusion criteria were biomechanical studies that involved nail–plate combination constructs for DFFs. Six observational studies were included. Of the included studies, five studies utilized synthetic bone models in testing, and one study used both synthetic and cadaveric bone models. All studies found NPCs to have significantly higher axial and torsional stiffness and resistance to loading than distal lateral femoral locking plate (DLFLP) constructs. The 11 mm NPCs were significantly stiffer than the 9 mm NPCs under torsional and axial loading. Only one of two studies found NPCs to have greater axial stiffness than dual-plate (DP) constructs. NPCs and DP constructs had greater torsional and axial stiffness than the plate-only or DP with medial distal tibial plate constructs. NPCs had less displacement and torque than the plate- or nail-only constructs under axial and torsional loads. NPCs demonstrate superior axial and torsional stiffness and resistance to mechanical loads compared to DLFLP. The varying performance between 11 mm and 9 mm NPCs suggests that construct diameter plays a role in mechanical stability. NPCs and DP constructs performed better than plate-only constructs. Future research should explore the impact of varying nail diameters and plate configurations on stability, as well as the clinical efficacy of NPCs across different patient populations, particularly those with varying bone densities, to better understand their performance in real-world scenarios.

Biomechanical Comparison of Three Locking Compression Plate Constructs from Three Manufacturers under Cyclic Torsional Loading in a Fracture Gap Model.

The aim of the study was to compare the stiffness and cyclic fatigue of locking compression plate constructs from three manufacturers, DePuy Synthes (DPS), Knight Benedikt (KB), and Provet Veterinary Instrumentation (Vi), under cyclic torsion. The constructs of DPS, KB, and Vi were assembled by fixing a 10-hole 3.5-mm stainless steel locking compression plate 1 mm away from a validated bone model with a fracture gap of 47 mm. The corresponding drill guides and locking screws were used. Three groups of six constructs were tested in cyclic torsion until failure. There was no significant difference in initial stiffness between DPS constructs (28.83 ± 0.84 N·m/rad) and KB constructs (28.38 ± 0.81 N·m/rad), and between KB constructs and Vi constructs (27.48 ± 0.37 N·m/rad), but the DPS constructs were significantly stiffer than the Vi constructs. The DPS constructs sustained the significantly highest number of cycles (24,833 ± 2,317 cycles) compared with KB constructs (16,167 ± 1,472 cycles) and Vi constructs (19,833 ± 4,792 cycles), but the difference between KB and Vi constructs was not significant. All constructs failed by screw damage at the shaft between the plate and the bone model. DPS constructs showed superior initial torsional stiffness and cyclic fatigue life than Vi constructs, whereas KB and Vi constructs shared comparable results. Further investigation is required to assess the clinical significance of these biomechanical differences.

OUTCOMES OF DISTAL FEMUR FRACTURE IN THE ELDERLY TREATED WITH EITHER SINGLE PLATE OR DUAL PLATING OR NAIL-PLATE COMBINATION: A RETROSPECTIVE ANALYSIS FROM A SINGLE CENTRE

IntroductionDistal femur fracture fixation in elderly presents significant challenges due to osteoporosis and associated comorbidities. There has been an evolution in the management of these fractures with a description of various surgical techniques and fixation methods; however, currently, there is no consensus on the standard of care. Non-union rates of up to 19% and mortality rates of up to 26 % at one year have been reported in the literature. Delay in surgery and delay in mobilisation post-operatively have been identified as two main factors for high rate of mortality. As biomechanical studies have proved better stability with dual plating or nail-plate combination, a trend has been shifting for past few years towards rigid fixation to allow early mobilisation. Our study aims to compare outcomes of distal femur fractures managed with either single plate (SP), dual plating (DP) or nail-plate construct (NP).MethodsA retrospective review of patients aged above 65 years with distal femur fractures (both native and peri-prosthetic) who underwent surgical management between June 2020 and May 2023 was conducted. Patients were divided into three groups based on mode of fixation - single plate or dual plating or nail-plate construct. AO/OTA classification was used for non-periprosthetic, and Unified classification system (UCS) was used for periprosthetic fractures. Data on patient demographics, fracture characteristics, surgical details, postoperative complications, re-operation rate, radiological outcomes and mortality rate were evaluated. Primary objective was to compare re-operation rate and mortality rate between 3 groups at 30 days, 6 months and at 1 year.ResultsA cohort of 32 patients with distal femur fractures were included in this study. 91% were females and mean age was 80.97 (range 68–97). 18 (53%) were non-periprosthetic fracture and 14 (47%) were periprosthetic fractures.18 patients underwent single plate fixation (AO/OTA 33A – 8, 33B/C – 2, UCS V3B – 5, V3C – 3),10 patients had dual plate fixation (AO/OTA 33A – 1, 33B/C – 4, UCS V3B – 3, V3C – 2) and 4 patients underwent nail-plate combination fixation (AO/OTA 33A – 4). 70.5% patients had surgery within 36 hours of admission and 90% within 48 hours. Analysis showed no re-operation at 30 days, 6 months in all 3 groups. At 1 year one patient had re-operation in dual-plating periprosthetic group (Distal femur replacement done for failed fixation). Three patients (16%) in single plate group had re-operation at 2 years (2 for peri-implant fracture and 1 for infection). None of the patients treated with Nail-plate combination had re-operation. Mortality rate at 30 days was 0% in among all the 3 groups. At 6 months, it was 16% in single plate group and 0% in DP and NP groups at 6 months and at 1 year mortality rate was 27% in SP group, 10% in DP and 0% in NP group. Combined mortality rate was 0% at 30 days, 9% at 6 months and 18.7% at one year.ConclusionOur analysis provides insights into fixation methods of distal femur fractures in elderly patients. We conclude that a lower re-operation rate and mortality rate can be achieved with early surgery and rigid fixation with either dual plating or nail-plate construct to allow early mobilisation. Further prospective studies are warranted to confirm these findings and guide the selection of optimal surgical strategies for these challenging fractures.

Independent volumetric internal fixation reduces posterior column acetabular fracture site motion as compared to plate/screw construct: A biomechanical analysis

Aims & objectivesTo establish whether a suprapectineal pelvic reconstruction plate and posterior column screw (P&S) construct or a single 6.5-mm cannulated posterior column screw (PCS) construct demonstrates greater mechanical stability for fixation of acetabulum fractures involving the posterior column (PC). We hypothesized that the PCS construct would result in less fracture site motion. Materials & methodsTwelve fourth-generation composite hemipelvi were utilized, 6 for each construct. The P&S construct consisted of a suprapectineal pelvic reconstruction plate with two 3.5-mm posterior column screws crossing the fracture site in lag-by-technique fashion and two screws anchoring the plate to the sciatic buttress. The PCS construct consisted of a single 6.5-mm partially threaded cannulated screw placed in an antegrade fashion. Both fixation models were cyclically loaded at 0.5 cycles/second at 400N and 800N, first in a sit-to-stand position that is expected during recovery, and subsequently in a squat-to-stand position to test overload conditions. ResultsUnder sit-to-stand loading, the PCS construct resulted in less motion at the fracture site than the P&S construct (0.06 ± 0.02 mm vs 0.1 ± 0.02 mm at 400N, p = 0.02; 0.13 ± 0.03 mm vs 0.19 ± 0.04 mm at 800N, p = 0.03). The PCS construct also demonstrated less fracture site motion under squat-to-stand loading (0.22 ± 0.13 mm vs 1.9 ± 0.5 mm at 400N, p = < 0.001; 1.48 ± 0.44 mm vs 4.77 ± 0.3 mm at 800N, p = < 0.001). At 800 N, half of the repairs failed during squat-to-stand loading (2 PCS, 4 P&S). ConclusionFixation of the posterior column of the acetabulum with a 6.5-mm cannulated screw demonstrated comparable fracture motion upon loading compared to the plate and screw construct.

Comparative analysis of risk factors associated with degeneration of adjacent segments: zero-profile anchored spacer vs. anterior cervical plate and cage construct.

Anterior cervical discectomy and fusion (ACDF) is an established treatment for cervical degenerative disc disease, but cervical spine surgery may affect sagittal alignment parameters and induce adjacent segment degeneration (ASD). This study aimed to determine the risk factors for developing ASD following anterior cervical plate and cage (ACPC) compared with the use of zero-profile anchored spacer (ROI-C). A retrospective contrastive study included 105 patients who underwent ACPC or ROI-C between January 2014 and October 2019 at our treatment centre. There were 50 cases in the ROI-C group and 55 patients in the ACPC group. Clinical and radiological results and the incidence of ASD were assessed after surgery. All patients were further divided into the ASD and non-ASD groups for subgroup analysis. At each follow-up time, there was no statistically significant in radiographic parameters between the two groups. The overall ASD rate was higher in the ACPC group than in the ROI-C group (65.5% vs. 44.0%, p = 0.027). The low preoperative Cobb angle, low preoperative segment angle (SA), and loss of Cobb (ΔCobb) were significantly correlated with ASD. However, clinical outcomes were not associated with ASD at any postoperative follow-up visit. Equally good therapeutic effects were achieved with both the ROI-C and ACPC. The occurrence of ASD was considerably higher in the ACPC group than in the ROI-C group. The preoperative Cobb angle, preoperative SA, and ΔCobb were the most associated with an increase in the risk of ASD.

Current Concepts in Management of Distal Femur Fractures

Recent studies report the overall incidence of distal femur fractures as 8.7/100,000/year. This incidence is expected to rise with high energy motor vehicle collisions and elderly osteoporotic fractures in native and prosthetic knees keep increasing. These fractures are more common in males in the younger age spectrum while females predominate for elderly osteoporotic fractures. Surgical treatment is recommended for these fractures to maintain articular congruity, enable early joint motion and assisted ambulation. Over the last two decades, development of minimally invasive and quadriceps sparing surgical approaches, availability of angle stable implants have helped achieve predictable healing and early return to function in these patients. Currently, laterally positioned locked plate is the implant of choice across all fracture patterns. Retrograde with capital implantation of intramedullary nails with provision for multiplanar distal locking is preferred for extra-articular and partial articular fractures. Even with these advancements, nonunion after distal femur fracture fixation can be as high as 19%. Further recent research has helped us understand the biomechanical limitations and healing problems with lateral locked plate fixation and intramedullary nails. This has lead to development of more robust constructs such as nail-plate and double plate constructs aiming for improved construct strength and to minimise failures. Early results with these combination constructs have shown promise in high risk situations such as fractures with extensive metaphyseal fragmentation, osteoporosis and periprosthetic fractures. These constructs however, run the risk of being over stiff and can inhibit healing if not kept balanced. The ideal stiffness that is needed for fracture healing is not clearly known and current research in this domain has lead to the development of smart implants which are expected to evolve and may help improve clinical results in future.

Locked plate constructs are not necessarily stiffer than nonlocked constructs: A biomechanical investigation of locked versus nonlocked diaphyseal fixation in a human cadaveric model of nonosteoporotic and osteoporotic distal femoral fractures.

The objective of this study was to compare the biomechanical properties of locked and nonlocked diaphyseal fixation in a model of distal femur fractures using osteoporotic and nonosteoporotic human cadaveric bone. A supracondylar osteotomy was created to mimic a fracture (OTA/AO 33A3) in osteoporotic (n = 4) and nonosteoporotic (n = 5) cadaveric distal femurs. The left and right femurs of each pair were instrumented with a distal femoral locking plate and randomly assigned to have diaphyseal fixation with either locked or nonlocked screws. The construct was cyclically axially loaded, and construct stiffness and load to failure were evaluated. In osteoporotic bone, locked constructs were more stiff than nonlocked constructs (mean 143 vs. 98 N/mm when all time points combined, P < 0.001). However, in nonosteoporotic bone, locked constructs were less stiff than nonlocked constructs (mean 155 N/mm vs. 185 N/mm when all time points combined, P < 0.001). In osteoporotic bone, the average load to failure was greater in the locked group than in the nonlocked group (mean 1159 vs. 991 N, P = 0.01). In nonosteoporotic bone, the average load to failure was greater for the nonlocked group (mean 1348 N vs. 1214 N, P = 0.02). Bone mineral density was highly correlated with maximal load to failure (R2 = 0.92, P = 0.001) and stiffness (R2 = 0.78, P = 0.002) in nonlocked constructs but not in locked constructs. Contrary to popular belief, locked plating constructs are not necessarily stiffer than nonlocked constructs. In healthy nonosteoporotic bone, locked diaphyseal fixation does not provide a stiffer construct than nonlocked fixation. Bone quality has a profound influence on the stiffness of nonlocked (but not locked) constructs in distal femur fractures.

OPerative versus non-opERAtive management of isolated ULNAr diaphyseal fractures (OPERA-Ulna): protocol for a randomized controlled trial.

Isolated fractures of the ulnar diaphysis are uncommon, occurring at a rate of 0.02 to 0.04 per 1,000 cases. Despite their infrequency, these fractures commonly give rise to complications, such as nonunion, limited forearm pronation and supination, restricted elbow range of motion, radioulnar synostosis, and prolonged pain. Treatment options for this injury remain a topic of debate, with limited research available and no consensus on the optimal approach. Therefore, this trial aims to compare clinical, radiological, and functional outcomes of two treatment methods: open reduction and internal fixation (ORIF) versus nonoperative treatment in patients with isolated ulnar diaphyseal fractures. This will be a multicentre, open-label, parallel randomized clinical trial (under National Clinical Trial number NCT01123447), accompanied by a parallel prospective cohort group for patients who meet the inclusion criteria, but decline randomization. Eligible patients will be randomized to one of the two treatment groups: 1) nonoperative treatment with closed reduction and below-elbow casting; or 2) surgical treatment with ORIF utilizing a limited contact dynamic compression plate and screw construct. The primary outcome measured will be the Disabilities of the Arm, Shoulder and Hand questionnaire score at 12 months post-injury. Additionally, functional outcomes will be assessed using the 36-Item Short Form Health Survey and pain visual analogue scale, allowing for a comparison of outcomes between groups. Secondary outcome measures will encompass clinical outcomes such as range of motion and grip strength, radiological parameters including time to union, as well as economic outcomes assessed from enrolment to 12 months post-injury. This trial has been approved by the lead site Conjoint Health Research Ethics Board (CHREB; REB14-2004) and local ethics boards at each participating site. Findings from the trial will be disseminated through presentations at regional, national, and international scientific conferences and public forums. The primary results and secondary findings will be submitted for peer-reviewed publication.

Advances in Dynamization of Plate Fixation to Promote Natural Bone Healing.

The controlled dynamization of fractures can promote natural fracture healing by callus formation, while overly rigid fixation can suppress healing. The advent of locked plating technology enabled new strategies for the controlled dynamization of fractures, such as far cortical locking (FCL) screws or active plates with elastically suspended screw holes. However, these strategies did not allow for the use of non-locking screws, which are typically used to reduce bone fragments to the plate. This study documents the first in vivo study on the healing of ovine tibia osteotomies stabilized with an advanced active plate (AAP). This AAP allowed plate application using any combination of locking and non-locking screws to support a wide range of plate application techniques. At week 9 post-surgery, tibiae were harvested and tested in torsion to failure to assess the healing strength. The five tibiae stabilized with an AAP regained 54% of their native strength and failed by spiral fracture through a screw hole, which did not involve the healed osteotomy. In comparison, tibiae stabilized with a standard locking plate recovered 17% of their strength and sustained failure through the osteotomy. These results further support the stimulatory effect of controlled motion on fracture healing. As such, the controlled dynamization of locked plating constructs may hold the potential to reduce healing complications and may shorten the time to return to function. Integrating controlled dynamization into fracture plates that support a standard fixation technique may facilitate the clinical adoption of dynamic plating.

The effect of body weight on interfragmentary fracture strain in plate fixation of distal femur fractures: A finite element analysis

IntroductionDistal femur fractures are difficult to successfully treat due to high rates of nonunion. Obesity is an independent prognostic risk factor for nonunion. Advances in finite element analyses (FEAs) have allowed researchers to better understand the performance and behavior of constructs at the bone-implant interface under a variety of conditions. The purpose of this study is to determine the impact of body weight on fracture strain in a lateral locking plate construct for supracondylar femur fractures and whether additional construct rigidity is beneficial to optimize fracture strain in high body mass patients. HypothesisWe hypothesized that increased loads would produce a higher interfragmentary strain (IFS), which could be decreased by shortening the working length of the construct. Materials and methodsA 3D finite element analysis was performed on two separate femur models with a comminuted supracondylar distal femur fracture fixed with a lateral distal femoral locking plate in bridging mode with Ansys software. Axial forces were varied to recreate the effect of load from normal and high body mass patients. Working length and screw density of the construct were varied for each condition. Measurements of interfragmentary strain and shear motion (SM) were compared. ResultsDoubling the axial load from 70kg (control) to 140kg (high body mass) increased the interfragmentary strain by an average of 76% for the three working lengths (3.38%±1.67% to 4.37%±0.88% at the baseline working length (BWL), 1.42%±1.00% to 2.87%±2.02% at the intermediate working length (IWL) and 0.62%±0.22% to 1.22%±0.42% at the short working length (SWL)). On average, decreasing the working length in the 140kg load reduced the mean IFS to within 15% of the mean IFS of the 70kg load at the longer working length (2.87%±2.02% at IWL 140kg versus 3.38%±1.67% at BWL 70kg and 1.22%±0.45% SWL 140kg versus 1.42±1.00% IWL 70kg). DiscussionIncreased axial load increases interfragmentary strain in an AO/OTA 33A distal femur fracture fixed with a lateral distal femoral locking plate. Decreasing the working length of the fixation construct in the high body mass model decreased interfragmentary strain. Higher loading conditions reflective of high body mass patients should be considered in studies investigating optimization of fracture strain. Level of proofV; Finite Element Analysis (FEA).

Bilateral first metatarsophalangeal joint arthrodesis: An investigation of functional, surgical and radiological outcomes

BackgroundFirst metatarsophalangeal joint (MTPJ) arthrodesis is a commonly utilised procedure. In this study, the authors aim to explore functional outcomes of patients undergoing nonsynchronous bilateral first MTPJ arthrodesis under the care of a single surgeon using a compression screw/locking plate construct. MethodsThis is a prospectively collected, retrospectively analysed case series of fifty five patients who underwent bilateral nonsynchronous first MTPJ arthrodesis. Clinical and radiological outcomes were assessed preoperatively and at a minimum of two years postoperatively. Clinical outcomes were assessed using the Foot and Ankle Outcome Score (FAOS), the Self-Reported Foot and Ankle Score (SEFAS) and the Sports Questionnaire version 1 (SQ). Postoperative radiographs were used to assess evidence of union and compare both hallux valgus and intermetatarsal angles. Removal of hardware, revision surgery and correction of deformities were also recorded. ResultsFifty five patients were included in the study. There was statistically significant improvements in all five facets of the FAOS (p value < 0.05). The mean postoperative SEFAS was 45.1. In total, patients participated in thirteen different sporting activities. This represented 92 patient specific activities preoperatively and 104 postoperatively. The most common activities were walking, cycling and swimming. Overall, 94.5% (N = 52) of the cohort were satisfied with their return to sport while 98.2% (N = 54) would recommend bilateral first MTPJ arthrodesis. Mean reductions in hallux valgus angles and intermetatarsal angles were noted at 18.87 and 4.69 degrees respectively. There was one non-union in the cohort which required revision surgery. One patient required removal of hardware. ConclusionsBilateral first MTPJ arthrodesis is a safe and effective surgical option for patients with bilateral first MTPJ pathology. It has a high union rate, low complication rate and significantly improves clinical outcomes and allows patients reliably return to physical activities.

Evaluation of the Stability of Internal Fixation Constructs in a Low Distal Tibia Extra-articular Cadaveric Fracture Model: A Comparative Biomechanical Study.

Introduction Despite the recent advances in implant design, the choice of an internal fixation modality for extra-articular distal tibia fractures remains controversial, and there is sparse literature comparing the stability of intramedullary nails and locked plates for such fractures. Hence, we conducted a biomechanical study on an AO type 43A3 tibia fracturecadaveric model stabilized by four different constructs, viz., intramedullary (IM) interlocking nail, anteromedial plate, anterolateral plate, and posterior plate.An AO type 43A3 fracture is defined as an extra-articular fracture of the distal tibia with metaphyseal comminution. Methods A biomechanical comparative study on formalin-preserved human cadaveric tibiae was undertaken; a total of four groups were tested, with eight bones in each group. Out of the 32 cadaveric tibiae, 19 bones belonged to male cadavers, and 13 bones belonged to female cadavers. All bones were dissected from age-appropriate cadavers and fixed with an implant, followed by the creation of a 1 cm osteotomy to simulate an AO type 43A3 fracture. All fixation constructs were subjected to three-point bending tests in the anteroposterior (AP) and mediolateral (ML) planes. Three parameters, viz., bending stiffness, peak fracture gap angle, and neutral zone, were evaluated on the load-displacement curves. Afixation construct was deemed biomechanically stable if it had a highbending stiffness, a low neutral zone (inherent toggle in the construct by its weight), and a low peak fracture gap angle. Results Out of the four implants tested, locked IM nails exhibited the maximum biomechanical stability in terms of higher bending stiffness, smaller peak fracture gap angle, and smaller neutral zones. The IM nail exhibited the highest bending stiffness in the AP plane, and the anterolateral plate had the lowest bending stiffness, and the difference was statistically significant (p= 0.032).In the AP plane, the anterolateral plate exhibited a bending stiffness of 1.51 ± 0.69 Nm/degree, whereas the intramedullary nail exhibited a bending stiffness of 2.34 ± 0.81 Nm/degree, and the posterior locked plate had a bending stiffness of 1.57 ± 0.44 Nm/degree. In the ML plane, the anterolateral plate exhibited the highest neutral zone as compared to the intramedullary nail, which had the lowest neutral zone, and the difference was statistically significant (p = 0.019). The intramedullary nail exhibited the lowest neutral zone of 0.46 ± 0.31 degrees, whereas the posterior locked plate exhibited a neutral zone of 0.78 ± 0.43 degrees in the ML plane. The anterolateral plate exhibited a neutral zone of 1.43 ± 1.00 (expressed as mean ± SD) degrees in the mediolateral plane. Conclusion Our biomechanical study supports the recommendations of using a locked intramedullary nail for AO type 43A3 fractures. We concluded that the anterolateral plate construct exhibited the least biomechanical stability, in terms of lower AP bending stiffness and higher neutral zone. If the surgeon must choose a locked plating technique for any reason, the anterolateral locking plate should be avoided. If plating is at all required, we can recommend both anteromedial and posterior locked plating as biomechanically sound options.

Effect of an Orthogonal Locking Plate and Primary Plate Working Length on Construct Stiffness and Plate Strain in an In vitro Fracture-Gap Model.

The aim of this study was to compare stiffness and strain of an in vitro fracture-gap model secured with a primary 3.5-mm locking compression plate (LCP) at three primary plate working lengths without and with an orthogonal 2.7-mm LCP. Primary plate screw configurations modeled short working length (SWL), medium working length (MWL), and long working length (LWL) constructs. Construct stiffness with and without an orthogonal plate during nondestructive four-point bending and torsion, and plate surface strain measured during bending, was analyzed. Single plate construct stiffness was significantly, incrementally, lower in four-point bending and torsion as working length was extended. Addition of an orthogonal plate resulted in significantly higher bending stiffness for SWL, MWL, and LWL (p < 0.05) and torsional stiffness for MWL and LWL (p < 0.05). Single plate construct strain was significantly, incrementally, higher as working length was extended. Addition of an orthogonal plate significantly lowered strain for SWL, MWL, and LWL constructs (p < 0.01). Orthogonal plate application resulted in higher bending and torsional construct stiffness and lower strain over the primary plate in bending in this in vitro model. Working length had an inverse relationship with construct stiffness in bending and torsion and a direct relationship with strain. The inverse effect of working length on construct stiffness was completely mitigated by the application of an orthogonal plate in bending and modified in torsion.

Structural Allograft Versus Mechanical Interbody Devices Augmented With Osteobiologics in Anterior Cervical Discectomy and Fusion: A Systematic Review.

Systematic Literature Review. Perform a systematic review evaluating postoperative fusion rates for anterior cervical discectomy and fusion (ACDF) using structural allograft vs various interbody devices augmented with different osteobiologic materials. Comprehensive literature search using PubMed, Embase, The Cochrane Library, and Web of Science was performed. Included studies were those that reported results of 1-4 levels ACDF using pure structural allograft compared with a mechanical interbody device augmented with an osteobiologic. Excluded studies were those that reported on ACDF with cervical corpectomy; anterior and posterior cervical fusions; circumferential (360° or 540°) fusion or revision ACDF for nonunion or other conditions. Risk of bias was determined using the Cochrane review guidelines. 8 articles reporting fusion rates of structural allograft and an interbody device/osteobiologic pair were included. All included studies compared fusion rates following ACDF among structural allograft vs non-allograft interbody device/osteobiologic pairs. Fusion rates were reported between 84% and 100% for structural allograft, while fusion rates for various interbody device/osteobiologic combinations ranged from 26% to 100%. Among non-allograft cage groups fusion rates varied from 73-100%. One study found PEEK cages filled with combinations of autograft, allograft, and demineralized bone matrix (DBM) to have an overall fusion rate of 26%. In one study comparing plate and zero-profile constructs, there was no difference in fusion rates for two-level fusions. There was limited data comparing fusion outcomes of patients undergoing ACDF using structural allograft vs interbody devices augmented with osteobiologic materials to support superiority of one method.

Intramedullary Nailing Technique for Proximal Humeral Fractures Using a Straight Antegrade Nail with Locking Tuberosity Fixation.

Intramedullary straight nail fixation of proximal humeral fractures using a locking mechanism provides advantages compared with plating, including (1) less soft-tissue dissection, which preserves periosteal blood supply and soft-tissue attachments; (2) improved construct stability for comminuted fractures or osteopenic bone; and (3) shorter operative time for simpler fractures. The patient is placed in the beach-chair position with the head of the bed elevated approximately 45°. The fracture is reduced with use of closed or percutaneous methods, ideally, or with an open approach if required. Temporary fragment fixation with percutaneous Kirschner wires can be utilized. A 1-cm incision is made just anterior to the acromioclavicular joint, overlying the zenith of the humeral head and in line with the diaphysis. A guide-pin is then placed through this incision and is verified to be centrally located and in line with the humeral diaphysis on fluoroscopic views. The guide-pin is advanced into the diaphysis. A cannulated 9-mm reamer is inserted over the guide-pin to create a starting position. The nail is then inserted, with adequate fragment reduction maintained until the proximal nail portion is buried under the subchondral humeral head. The proximal screw trajectory and alignment are checked fluoroscopically. The proximal locking screws are pre-drilled and inserted first using percutaneous drill sleeves through the radiolucent targeting jig. The screw is inserted through the guide and is advanced into the nail until appropriately seated. This process is then repeated for the other proximal screws as necessary. Finally, the distal diaphyseal screws are pre-drilled and inserted in a similar percutaneous fashion using the jig, and the jig is removed. Final orthogonal images are obtained. Copious irrigation of the incisions is performed and they are closed and dressed with a sterile dressing. The operative arm is placed in an abduction sling. Alternative treatment options for proximal humeral fractures include nonoperative treatment with use of a sling, percutaneous reduction and internal fixation with Kirschner wires, open reduction and internal fixation with a locking plate and screw construct, hemiarthroplasty, and anatomic or reverse total shoulder arthroplasty1. The presently described technique for proximal humeral fracture fixation using a straight, antegrade, locking nail allows for minimal soft-tissue disruption, preserving vascularity and soft-tissue support and achieving angularly stable fixation in often osteopenic bone. The superior and in-line entry point avoids complications of rotator cuff injury and/or subacromial impingement. The proximal locking screws avoid complications of screw penetration or migration. This technique is appropriate for surgically indicated Neer 2-, 3-, and 4-part humeral fractures, including in elderly patients, when the humeral head fragment remains viable1-5. Based on available Level-III and IV evidence using this technique, patients should expect recovered motion and the ability to perform daily activities independently, with a mean active elevation of 132° to 136°1,4,6, external rotation of 37° to 52°1,4,6, and internal rotation to L31. Pain scores improved significantly from preoperatively to postoperatively, with a mean pain score of 1.4 on the visual analogue scale3,4,6. Patient-reported outcomes were good to excellent, with Single Assessment Numerical Evaluation (SANE) scores of 80% to 81%1,6, mean Constant scores from 71 to 811,3,4,6, and high rates of patient satisfaction (97% satisfied or very satisfied)4. Studies also demonstrated good to excellent fracture healing, with no tuberosity migration and low rates of nonunion (0% to 5%)1,6 and humeral head necrosis (0% to 4%)1,4. Revision rates ranged from 10.5% to 16.7%4,6. The starting position of the guide-pin must be central and at the zenith of the humeral head on the anteroposterior Grashey and the scapular Y views, and the guide-pin must be aligned with the diaphysis prior to advancing it.Failure to bluntly dissect the percutaneous incisions risks injury to the axillary nerve.Verify correct version of the nail prior to drilling any screws, to avoid incorrect version and potential loss of functional rotation. ABD = abductionAP = anteroposteriorCT = computed tomographyER = external rotationFF = forward flexion (forward elevation)IR = internal rotationSANE = Single Assessment Numerical EvaluationSSV = Subjective Shoulder ValueVAS = Visual Analogue Scale.

Biomechanical Analysis of Headless Compression Screw Versus Tension Band Wiring for Proximal Interphalangeal Joint Arthrodesis

Proximal interphalangeal (PIP) joint arthrodesis is a procedure employed to address arthritis, instability, and deformity. Multiple fixation methods are available to maintain stability across the arthrodesis interval, including headless compression screws (HCSs), tension band wiring (TBW), plating, and Kirschner wire constructs. The purpose of this study was to compare the biomechanical properties of the HCS and TBW techniques. Thirty-two nonthumb digits from the paired upper limbs of four fresh frozen cadavers were divided into pairs, matching contralateral digits from the same specimen. One PIP joint of each pair was fused with an antegrade 3.5 mm HCS, and the second was fused with TBW using 0.035 in. Kirschner wires with 24-gauge dental wire. Each construct was then stressed to 10 N in the radial deviation, ulnar deviation, flexion, and extension planes, and stiffness (N/mm) was calculated. The fingers were stressed to failure in extension with the ultimate load and mode of failure recorded. When stressed in extension, the HCS construct had a significantly greater mean stiffness than the TBW construct (16.4 N/mm vs 10.8 N/mm). The stiffness in all other planes of motion were similar between the two constructs. The mean ultimate load to failure in extension was 91.4 N for the HCS and 41.9 N for the TBW. The most common mode of failure was fracture of the dorsal lip of the proximal phalanx (13/16) for the HCS and bending of the K-wires (15/16) for TBW. Arthrodesis of the PIP joint using a HCS resulted in a construct that was significantly stiffer in extension with greater than double the load to failure compared to TBW. Although the stiffness required to achieve successful PIP joint arthrodesis has not been well quantified, the HCS proved to be the most favorable construct with respect to initial strength and stability.