Gait and strength assessment following surgical repair by intramedullary nailing of isolated tibial shaft fracture.

The objective of the study was to evaluate the long-term strength and gait outcomes after intramedullary nailing of isolated tibial diaphyseal fractures. This retrospective cohort study was conducted at an academic Level I trauma center. Fifteen participants with isolated tibial diaphyseal fractures (OTA/AO 42) at least 2 years postoperative from intramedullary nailing (IMN) provided informed consent. The average age was 40 ± 14 (range, 24-69); there were nine men and six women. Knee flexion-extension strength data were collected. Temporal-spatial, kinematic, and kinetic gait parameters were measured and compared to historic control data. Participants completed the SF-36 and shortened musculoskeletal function assessment questionnaires. The mean length of follow-up between surgery and gait analysis was 6 ± 2 years. The fractured limb demonstrated deficits in quadriceps strength between 9.8% and 23.4% compared to the unaffected limb. Temporal-spatial parameters revealed slower walking speed, shorter stride length, decreased cadence, and shorter single-limb support time in the fractured limb. Altered kinematic and kinetic findings included a knee extension shift during stance, with an increased knee flexor moment demand and decreased total knee power during loading and midstance. These findings represent deficits in concentric and eccentric knee extensor activity. Additionally, the fractured limb demonstrated decreased ankle dorsiflexion during stance and diminished ankle push-off power. Long-term outcomes after IMN of tibial diaphyseal fractures demonstrate decreased quadriceps strength and altered gait parameters that may have implications to the high incidence of knee and ankle pain in the fractured limb.

Biomechanical Evaluation of Transverse Patella Fracture Fixation Using Headless Screws: A Comparison of Suture Versus Cable as a Tension Band.

OBJECTIVES: To explore the performance of headless screws with FiberWire Suture as a tension band and headless screws with a mini-cable tension band in patella fixation. METHODS: A transverse osteotomy was created in 6 matched pairs of fresh-frozen cadaver knee joints. One knee was randomly assigned to receive fixation with headless screws plus a cable tension band while the other was fixed with headless screws plus a suture tension band. Using a servo-hydraulic material testing system, the specimens were first tested nondestructively under 20% of the reported mean failure load with a standard technique of cannulated screws with tension band wiring. The specimen was then loaded to 1000 N to test the construct's failure strength. All tests were run under displacement-control with loading threshold. A motion analysis system was used to track the interfragmentary motion to assess fixation stability. RESULTS: In the nondestructive loading test, gap displacement under 150 N was 0.10 mm or less for 11 of 12 specimens, and the difference between the 2 groups was not statistically significant. In the destructive test, 3 of 12 specimens maintained reduction (gap <2 mm) at the maximum load of 1000 N. Of the failed specimens, the mean strength was 648 ± 185 N for suture and 784 ± 228 N for cable. CONCLUSIONS: There was no significant difference in fixation strength or subfailure fragment displacement between the suture and cable tension band techniques when using headless screws.

A cadaveric biomechanical evaluation of anterior posterior compression II injuries.

PURPOSE: Pelvic fractures are associated with high morbidity and often require surgical intervention. An Anterior Posterior Compression (APC) II injury consists of disruption at the pubic symphysis and anterior sacroiliac joint. Studies investigating specific ligamentous contributions would aid in development of novel fixation techniques. The objective of this study is to determine the level of pelvic destabilization from progressive soft tissue disruptions associated with APC II injuries. METHODS: Six fresh-frozen cadaveric pelvises were dissected of soft tissues, preserving joint capsules and ligaments. Each pelvis was secured in a double-leg stance and joint motion was tracked with the specimens cyclically loaded to 60% body weight. Each specimen was measured in the intact state and again following stepwise destabilization to an APC II injury model (PS: sectioned pubic symphysis, IPS JOINT: PS + ipsilateral anterior sacroiliac, sacrotuberous, sacrospinous ligaments sectioned, IPS LIGS: IPS JOINT + ipsilateral interosseous ligaments sectioned, IPS JOINT+CONT ASI: IPS LIGS + contralateral anterior sacroiliac ligament disruption). RESULTS: Compared to the intact state, there was a statistically significant increase in movement in the IPS JOINT (ipsilateral 177%, p<0.001; contralateral 46%, p<0.005) and IPS JOINT+CONT ASI (ipsilateral 184%, p<0.002; and contralateral 62%, p<0.002) states bilaterally. No significant change was demonstrated in the PS or IPS LIGS state. CONCLUSION: Disruption of ipsilateral ligamentous structures destabilized both sacroiliac joints. The interosseous and posterior sacroiliac ligaments provide the majority of stability of the sacroiliac joint and will likely benefit most from surgical stabilization. LEVEL OF EVIDENCE: mechanism-based reasoning.

Outcome comparison between muscle and fasciocutaneous flaps after secondary orthopedic procedures.

Lower extremity wounds associated with fractures and bony defects often require secondary orthopedic procedures after flap coverage has been performed. In this study, we compare complications between muscle and fasciocutaneous flaps after secondary orthopedic procedures. A retrospective chart review study of all lower extremity soft tissue reconstructions by a single surgeon over seven years yielded a subgroup of patients who underwent secondary orthopedic procedures, including hardware removal, hardware revision, and bone grafting after flap reconstruction. Of 355 lower extremity, soft tissue reconstructions for orthopedic coverage performed in the time period studied, 102 patients underwent secondary orthopedic procedures after flap reconstruction. Of these, 54 received muscle flaps (52.94%), and 48 received fasciocutaneous flaps (47.06%). Using this subgroup of 102 patients, we compared muscle and fasciocutaneous flaps using three categories of wound complications following these secondary procedures: There were no superficial wounds requiring local wound care only in the muscle flap group (0%, n = 0) versus 4.17% (n = 2; p = 0.130) in the fasciocutaneous flap group. There were 2 lost flaps requiring surgical debridement and additional skin grafting in the muscle flaps group (3.70%) versus 2 (4.17%; p = 0.904) in the fasciocutaneous flap group. In the third category, flap loss requiring additional soft tissue reconstruction was 18.52% (n = 10) in the muscle group versus 2.08% (n = 1; p = 0.008) in the fasciocutaneous flap group. Our data support the existing literature indicating that fasciocutaneous flaps can tolerate secondary procedures better than muscle flaps and should initially be considered in patients with higher probability of needing additional orthopedic procedures after reconstruction.

Acute clavicle fixation after blunt chest trauma: effect on pulmonary outcomes and patient disposition.

PURPOSE: Clavicle fractures are common in patients who sustain blunt chest trauma (BCT). Recently, surgical fixation of rib fractures in patients with BCT has been shown to improve pulmonary and clinical outcomes. Therefore, the purpose of this study is to assess the role of early clavicle fixation (ECF) versus non-operative (NO) treatment for midshaft clavicle fractures in this same population. METHODS: A retrospective chart review was performed in patients with midshaft clavicle fractures and BCT at a Level I Trauma Center between 2007 and 2017. Patients with pre-existing pulmonary conditions and head injuries necessitating mechanical ventilation were excluded. Demographic data, injury mechanisms, and Thoracic Trauma Severity Scores (TTS) were analyzed. Inpatient pulmonary outcomes were assessed with serial vital capacity (VC) measurements, intubation, mechanical ventilation, and pulmonary complications data. In addition, intensive care unit (ICU) and hospital length of stay (LOS), mortality, discharge location, and incidence of postoperative complications in the ECF group were also measured. RESULTS: Thirty-six patients underwent ECF, and 24 underwent NO treatment. The ECF cohort was statistically younger and had a greater incidence of clavicle fracture shortening than the NO group. There was no difference in pulmonary outcomes, ICU or hospital LOS, or mortality between groups. There were no complications associated with ECF. Patients who underwent ECF were more likely to discharge to home. There were no postoperative complications associated with ECF. CONCLUSION: ECF of midshaft clavicle fractures does not improve pulmonary outcomes in patients with BCT. However, despite the lack of pulmonary benefit, there appears to be no added risk of harm. Therefore, ECF is a reasonable consideration in this patient population who otherwise meet clavicle fracture operative indications.

Impact of Internal Malrotation of the Femur Followed by Derotational Osteotomy as Demonstrated by 3D Gait Analysis: A Case Report.

CASE: An 18-year-old man with 48° of internal malrotation of the femur after nailing underwent derotational osteotomy with gait dynamics and electromyography data collected preoperatively and postoperatively. Hip abduction and internal foot progression angles were significantly deviated from normal preoperatively compared with the contralateral side. At 10 months postoperatively, the hip was abducted and externally rotated throughout the entire gait cycle. His Trendelenburg gait had resolved, and he reported no residual functional concerns. Before corrective osteotomy, walking velocity was significantly slower with shorter stride lengths. CONCLUSION: Significant internal malrotation of the femur impairs hip abduction and foot progression angles as well as gluteus medius activation during ambulation. Derotational osteotomy considerably corrected these values.

Rare popliteal mass following retrograde nailing of ballistic femur fracture: a case report.

INTRODUCTION: Civilian ballistic injuries are commonly associated with fracture, vascular injury, and soft tissue trauma. Posttraumatic pseudoaneurysms represent an extremely rare subset of vascular injuries following ballistic fractures. CASE: We present the rare case of a posttraumatic pseudoaneurysm that occurred after retrograde femoral nailing of a ballistic distal femur fracture. The patient presented in clinic postoperatively with a pulsatile popliteal mass. Distal pulses were intact but subsequent ultrasound and angiography revealed a pseudoaneurysm of the distal superficial femoral artery. The pseudoaneurysm was subsequently treated with a covered stent and the patient's recovery was uncomplicated. CONCLUSION: Due to the potential life and limb-threating complications from pseudoaneurysm rupture, this case report emphasizes the early recognition and expeditious management of vascular complications following ballistic fractures in the civilian population.

Systematic review of sacroiliac joint motion and the effect of screw fixation.

BACKGROUND: Pelvic injuries that disrupt the sacroiliac joints often require surgical intervention to restore stability. Quantitative characterization of sacroiliac motion in response to physiologic loading provides important metrics of adequate fixation in the evaluation of newly emerged fixation techniques. The objective of this study was to systematically review and evaluate biomechanical evidence on the motion of the sacroiliac joint in its normal, destabilized, and stabilized states. METHODS: We searched the PubMed database for studies available until June 2020 using keywords: sacroiliac, biomechanic*, and fixation. Publications of any in vivo or in vitro biomechanical study that included measurements of the range of motion at the sacroiliac joint were considered. FINDINGS: We identified and screened 176 total records, and 13 articles of them met inclusion criteria and were used in this review. The average sacroiliac joint range of motion of the intact pelvis was 1.88° in flexion/extension, 0.85° in lateral bending, 1.26° in axial rotation. Of the 13 studies, four reported sacroiliac motion from a destabilized state, while seven reported the motion after stabilization. A forest plot of the stabilized data set in flexion/extension showed that while the heterogeneity was poor, the weighted effect size of the changes from the intact state to the stabilized state was 0.0%. INTERPRETATION: Quantitative evidence on sacroiliac joint motion relating to pelvic injuries or fixation is limited. Our results indicate that the pooled intact range of motion from the literature may serve as a viable reference to quantify the effectiveness of new stabilization techniques. LEVEL OF EVIDENCE: Level V, systematic review. STUDY TYPE: Therapeutic- investigating the results of a treatment.

Biomechanical Comparison of Tension Band Fixation of Patella Transverse Fracture: Headless Screws Versus Headed Screws.

OBJECTIVE: This study aimed to investigate the stability and strength of tension band wire fixation using headless compression screws versus headed screws for transverse patella fractures. METHODS: Six matched pairs of fresh-frozen cadaveric knees with transverse osteotomies created at the midpoint of the patella were surgically fixed, with one knee randomly receiving fixation with headless screws (Acumed Acutrak 4/5) and the other with headed screws (Synthes 4.0 partially threaded cannulated screws). The specimens were mounted onto a servohydraulic load frame in a 45-degree flexed position and loaded through the quadriceps tendon. Interfragmentary movement was recorded with a motion analysis system. The initial fixation stiffness, range of interfragmentary motion, and strength of the headless screw construct were compared with the headed screw construct. Failure was defined as either a sudden drop in applied tendon force or 2 mm of separation on the anterior surface of the patella (ie, clinical failure), whichever occurred first. RESULTS: Mean primary interfragmentary motion was 0.31 ± 0.28 degrees for the headed screws and 0.10 ± 0.06 degrees for headless screws under 150 N load (P = 0.03). Mean construct stiffness was 277 ± 243 N/degrees for the headed screws and 510 ± 362 N/degrees for the headless screws (P = 0.03). None of the constructs from either group displayed structural failure before reaching the clinical failure gap of 2 mm. The mean clinical failure strength was 808 ± 183 N for the headless screws construct and 520 ± 241 N for the headed screws construct (P = 0.03). CONCLUSIONS: Headless screw tension band fixation demonstrated superior biomechanical behaviors over standard headed screw fixation with higher construct rigidity, smaller interfragmentary motion, and greater fixation strength.

Murine model of large-vein electrolytic injury induction of thrombosis with slow resolution.

Deep vein thrombosis (DVT) and its sequela, pulmonary embolism, occur at a rate of 1 per 1000 person/year. Experimental models for evaluation of DVT have many short-comings, such as mechanical occlusion or stenosis to cause thrombosis, rather than the clinical scenario of thrombosis causing occlusion/stenosis. The goal of this study was to develop a model of flow-based large-vein thrombosis with resistance to resolution, to model clinical DVT behavior. Adult male C57Bl/6 mice underwent thrombus induction via an electrolytic injury to the femoral vein (3V positive current for 90s), with subsequent intra-vital fluorescence quantitation of platelet and fibrin accumulation through the first 60 min, and final histomorphometric volume evaluation at 1, 7, 14, and 28 days. Platelet accumulation at the injury site was comparable to a milder electrolytic injury, whereas fibrin was greatly augmented by 60 min in the more severe injury model. Thrombi showed persistent presence at 1 and 7 days, with remodeling to a stenotic fibrosis that encroached into the lumen at 14 and 28 days. The thrombotic/fibrotic volume within the femoral vein fell by 23% from 1 to 7 days, but had a residual presence at 28 days that was 31% the 1-day volume. This new model may provide an alternative approach to evaluating DVT persistence and therapeutic inhibition, to develop a better understanding of the clinical progression of DVT to thrombophlebitis.

Stability of unicortical locked fixation versus bicortical non-locked fixation for forearm fractures.

Locking plate fixation is being widely applied for fixation of forearm fractures and has many potential advantages, such as fixed angle fixation and improved construct stability, especially in osteoporotic bone. Biomechanical data comparing locking devices to commonly used Low Contact Dynamic Compression (LCDCP) plates for the fixation of forearm fractures has been lacking. The purpose of this study was to compare the fixation stability of a 3.5-mm unicortical locked plate with bicortical non-locked LCDCP plates. Six matched pairs of fresh frozen cadaveric forearms were randomly assigned to unicortical locked and bicortical unlocked groups. Non-destructive four-point bending and torsional test was performed on the ulna and radius separately, using a servohydraulic testing system to obtain construct stiffness of the intact specimens and specimens after osteotomy and plating. The specimens were then loaded to failure to test the fixation strength. The locked unicortical fixation showed significantly higher bending stiffness than the unlocked bicortical fixation, but with significantly lower stiffness and strength in torsion. Fixation strength was comparable between the two groups under bending, but significantly greater in the bicortical non-locked group under torsion. Findings from this study suggest that postoperative rehabilitation protocols may need modification to limit torsional loading in the early stage when using locked unicortical fixation. The study also points out the potential advantage of a hybrid fixation that combines locked unicortical and unlocked bicortical screws.

Incomplete resolution of deep vein thrombosis under reduced flow conditions.

INTRODUCTION: Post-thrombotic syndrome is a major complication of deep vein thrombosis (DVT), occurring in up to 1/3 of first-episode DVT patients. Non-ambulatory patients have increased risk for both DVT and post-thrombotic syndrome. Experimental models are lacking that can serve as reasonable in vivo clinical analogues for poor resolution of DVT that can lead to post-thrombotic syndrome. MATERIALS AND METHODS: A murine model of combined DVT and reduced flow was developed that results in persistent vein wall remodeling of poorly resolved thrombus. An electrolytic-injury model of venous thrombosis was created in the femoral veins of adult CD-1 mice, either with or without upstream flow reduction (10% of normal flow), with subsequent histomorphometric and immunohistochemical evaluation out to 28days. RESULTS: Most venous thrombi with normal flow resolved, with little evidence of thrombus or vein wall changes 4 or more days after thrombus induction. In contrast, reduced flow had a prolonging effect on thrombus presence, resulting in long-term remodeling of the thrombus and vein wall, persistent out to 28days. There was little evidence of monocyte or neutrophil infiltration in remodeled tissue, with only partial smooth muscle cell phenotypic presence, suggesting a fibrotic nature of the residual thrombus. CONCLUSIONS: Flow reduction inhibits thrombotic resolution in veins with resultant long-term thrombus presence and subsequent vein wall remodeling. This model may offer clinical analogy to unresolved DVT that leads to post-thrombotic syndrome.

The use of cervical vertebrae plates for cortical substitution in posterior wall acetabular fractures.

We report a new technique for operative fixation of posterior wall acetabular fractures that require cortical substitution. This technique uses cervical vertebrae plates that are H-shaped as an alternative to the combination of standard locking or nonlocking pelvic reconstruction plates and cortical substitution plates, ie, spring plates. We believe this technique provides a more robust structural support with the plate acting as a cortical substitute in comminuted fracture patterns. Compared with pelvic reconstruction plates, cervical vertebrae plates are almost twice as wide. Additionally, the plate configuration allows more screws per unit length compared with pelvic reconstruction plates, potentially providing more points of fixation. Finally, cost comparison of the two plates shows the cervical vertebrae plates to be less expensive than standard pelvic reconstruction plates. Our series of 23 consecutive patients shows outcomes similar to the published literature for standard pelvic reconstruction plates, and initial results show no early hardware failure.

Increased venous versus arterial thrombosis in the Factor V Leiden mouse.

BACKGROUND: Deep vein thrombosis (DVT) occurs with high prevalence in association with the Factor V Leiden (R506Q) mutation, whereas most evidence suggests no correlation with clinical arterial thrombosis. OBJECTIVE: This study compared arterial to venous thrombosis in the mutationally analogous Factor V Leiden mouse. METHODS: Three separate vascular thrombosis models were evaluated in Fv(+/+) (wild-type), Fv(Q/+) (heterozygous) and Fv(Q/Q) (homozygous) Factor V Leiden mice. RESULTS: In a FeCl(3)-induced arterial thrombosis model, no statistical differences among the three genotypes were found in the time to thrombotic occlusion. In contrast, Fv(Q/+) and Fv(Q/Q) mice demonstrated larger femoral vein thrombi at 30 and 60 min compared to wild-types, with Fv(Q/Q) mice having statistically larger thrombi than both wild-type and Fv(Q/+) mice at 10 and 60 min and 24 h (p<0.05). In a model of thrombotic occlusion following arterial and venous anastomotic repair, both Fv(Q/+) and Fv(Q/Q) mice had higher rates of venous thrombosis than wild-types, but only Fv(Q/Q) homozygotes showed a statistically greater arterial occlusion rate than wild-types. CONCLUSION: The Factor V Leiden mouse demonstrated a greater propensity for venous vs. arterial thrombosis, paralleling clinical epidemiologic findings and supporting its use for research on deep vein thrombosis.

A murine model of deep vein thrombosis: characterization and validation in transgenic mice.

Deep vein thrombosis (DVT) occurs with high prevalence in association with a number of risk factors, including major surgery, trauma, obesity, bed rest (> 5 days), cancer, a previous history of DVT, and several predisposing prothrombotic mutations. A novel murine model of DVT was developed for applications to preclinical studies of transgenically constructed prothrombotic lines and evaluation of new antithrombotic therapies.A transient direct-current electrical injury was induced in the common femoral vein of adult C57BI/6 mice. A non-occlusive thrombus grew, peaking in size at 30 min, and regressing by 60 min, as revealed by histomorphometric volume reconstruction of the clot. Pre-heparinization greatly reduced clot formation at 10, 30, and 60 min (p < 0.01 versus non-heparinized). Homozygous FactorV Leiden mice (analogous to the clinical FactorV Leiden prothrombotic mutation) on a C57Bl/6 background had clot volumes more than twice those of wild-types at 30 min (0.121 +/- 0.018 mm3 vs. 0.052 +/- 0.008 mm3, respectively; p < 0.01). Scanning electron microscopy revealed a clot surface dominated by fibrin strands, in contrast to arterial thrombi which showed a platelet-dominated structure. This new model of DVT presents a quantifiable approach for evaluating thrombosis-related murine transgenic lines and for comparatively evaluating new pharmacologic approaches for prevention of DVT.