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.

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.

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.

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.

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.