Technical Factors Contributing to Nonunion in Supracondylar Distal Femur Fractures Treated With Lateral Locked Plating: A Risk-Stratified Analysis.

OBJECTIVE: To identify technical factors associated with nonunion after operative treatment with lateral locked plating. DESIGN: Retrospective cohort study. SETTING: Ten Level I trauma centers. PATIENT SELECTION CRITERIA: Adult patients with supracondylar distal femur fractures (OTA/AO type 33A or C) treated with lateral locked plating from 2010 through 2019. OUTCOME MEASURES AND COMPARISONS: Surgery for nonunion stratified by risk for nonunion. RESULTS: The cohort included 615 patients with supracondylar distal femur fractures. The median patient age was 61 years old (interquartile range: 46 -72years) and 375 (61%) were female. Observed were nonunion rates of 2% in a low risk of nonunion group (n = 129), 4% in a medium-risk group (n = 333), and 14% in a high-risk group (n = 153). Varus malreduction with an anatomic lateral distal femoral angle greater than 84 degrees, was associated with double the odds of nonunion compared to those without such varus [odds ratio, 2.1; 95% confidence interval (CI), 1.1-4.2; P = 0.03]. Malreduction by medial translation of the articular block increased the odds of nonunion, with 30% increased odds per 4 mm of medial translation (95% CI, 1.0-1.6; P = 0.03). Working length increased the odds of nonunion in the medium risk group, with an 18% increase in nonunion per 10-mm increase in working length (95% CI, 1.0-1.4; P = 0.01). Increased proximal screw density was protective against nonunion (odds ratio, 0.71; 95% CI, 0.53-0.92; P = 0.02) but yielded lower mRUST scores with each 0.1 increase in screw density associated with a 0.4-point lower mRUST (95% CI, -0.55 to -0.15; P < 0.001). Lateral plate length and type of plate material were not associated with nonunion. ( P > 0.05). CONCLUSIONS: Malreduction is a surgeon-controlled variable associated with nonunion after lateral locked plating of supracondylar distal femur fractures. Longer working lengths were associated with nonunion, suggesting that bridge plating may be less likely to succeed for longer fractures. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Risk factors for failure of manipulation under anesthesia in posttraumatic knee stiffness.

OBJECTIVES: To determine the proportion of patients who fail manipulation under anesthesia (MUA) as a treatment for posttraumatic knee stiffness and determine the risk factors for MUA failure. METHODS: A retrospective cohort study was performed at a level I trauma center. We identified 213 knees in 199 patients with arthrofibrosis treated by MUA within 1 year of injury from 2007 to 2020. The primary outcome was MUA failure as defined by need for repeat MUA or surgical release after MUA. Multivariable logistic regression was used to determine the association between MUA failure and potential risk factors. RESULTS: Overall, 111 knees (52%) failed treatment with MUA. An association was demonstrated between MUA failure and delay in treatment >90 days after injury (OR 3.6, p < 0.01), neurologic injury (OR 2.2, p = 0.02), and pre-procedure knee flexion <45° (OR 1.9, p < 0.01). The rate of failure for knees with no risk factors was 0% (0 of 14), 37% for knees with one risk factor (27 of 73), and 67% (84 of 126) for knees with two or more risk factors. CONCLUSION: For patients whose MUA is delayed beyond 90 days postinjury, pre-manipulation knee flexion is <45°, or those with associated neurologic injury; odds of MUA failing to correct posttraumatic arthrofibrosis are significantly increased. The likelihood of obtaining adequate range of motion (ROM) with MUA alone is lower than reported in other populations, with a higher likelihood of being treated with surgical release or additional MUA to attempt to obtain adequate ROM.

A biomechanical comparison of superior ramus plating versus intramedullary screw fixation for unstable lateral compression pelvic ring injuries,,.

INTRODUCTION: Management of the anterior component of unstable lateral compression (LC) pelvic ring injuries remains controversial. Common internal fixation options include plating and superior pubic ramus screws. These constructs have been evaluated in anterior-posterior compression (APC) fracture patterns, but no study has compared the two for unstable LC patterns, which is the purpose of this study. METHODS: A rotationally unstable LC pelvic ring injury was modeled in 10 fresh frozen cadaver specimens by creating a complete sacral fracture, disruption of posterior ligaments, and ipsilateral superior and inferior rami osteotomies. All specimens were repaired posteriorly with two fully threaded 7 mm cannulated transiliac-transsacral screws through the S1 and S2 corridors. The superior ramus was repaired with either a 3.5 mm pelvic reconstruction plate (n = 5) or a bicortical 5.5 mm cannulated retrograde superior ramus screw (n = 5). Specimens were loaded axially in single leg support for 1000 cycles at 400 N followed by an additional 3 cycles at 800 N. Displacement and angulation of the superior and inferior rami osteotomies were measured with a three-dimensional (3D) motion tracker. The two fixation methods were then compared with Mann-Whitney U-Tests. RESULTS: Retrograde superior ramus screw fixation had lower average displacement and angulation than plate fixation in all categories, with the motion at the inferior ramus at 800 N of loading showing a statistically significant difference in angulation. CONCLUSION: Although management of the anterior ring in unstable LC injuries remains controversial, indications for fixation are becoming more defined over time. In this study, the 5.5 mm cannulated retrograde superior ramus screw significantly outperformed the 3.5 mm reconstruction plate in angulation of the inferior ramus fracture at 800 N. No other significance was found, however the ramus screw demonstrated lower average displacements and angulations in all categories for both the inferior and superior ramus fractures.

The impact of COVID-19 restrictions on participant enrollment in the PREPARE trial.

Background: At the initiation of the COVID-19 pandemic, restrictions forced researchers to decide whether to continue their ongoing clinical trials. The PREPARE (Pragmatic Randomized Trial Evaluating Pre-Operative Alcohol Skin Solutions in Fractured Extremities) trial is a pragmatic cluster-randomized crossover trial in patients with open and closed fractures. PREPARE was enrolling over 200 participants per month at the initiation of the pandemic. We aim to describe how the COVID-19 research restrictions affected participant enrollment. Methods: The PREPARE protocol permitted telephone consent, however, sites were obtaining consent in-person. To continue enrollment after the initiation of the restrictions participating sites obtained ethics approval for telephone consent scripts and the waiver of a signature on the consent form. We recorded the number of sites that switched to telephone consent, paused enrollment, and the length of the pause. We used t-tests to compare the differences in monthly enrollment between July 2019 and November 2020. Results: All 19 sites quickly implement telephone consent. Fourteen out of nineteen (73.6%) sites paused enrollment due to COVID-19 restrictions. The median length of enrollment pause was 46.5 days (range, 7-121 days; interquartile range, 61 days). The months immediately following the implementation of restrictions had significantly lower enrollment. Conclusion: A pragmatic design allowed sites to quickly adapt their procedures for obtaining informed consent via telephone and allowed for minimal interruptions to enrollment during the pandemic.

Superficial Deltoid Ligament and Deep Deltoid Ligament Play Equally Important Roles in the Stability of Isolated Lateral Malleolus (OTA/AO 44-B1) Fractures: A Biomechanical Study.

OBJECTIVE: To evaluate the individual contributions to stability of the superficial and deep deltoid ligaments in the setting of SER IV ankle fractures. METHODS: Nineteen total cadaveric specimens were used. SER IV injuries were created with the rupture of either the superficial (SER IV-S) (n = 9) or deep deltoid (SER IV-D) (n = 10). These were tested by applying an external rotation force (1 Nm, 2 Nm, 3 Nm, and 4 Nm). Changes in the position of the talus were recorded with a 3D motion tracker. Injury conditions were compared with a 4-step general linear model with repeated measures. Injury condition was also compared with the intact state and to each other using 2-tailed t tests. RESULTS: The general linear model showed that increased loading had a significant effect with axial rotation (P = 0.02) and sagittal translation (P = 0.003). SER IV-S and SER IV-D showed significantly greater instability compared with the intact state in axial rotation (1 Nm, 2 Nm, and 3 Nm). SER IV-S and SER IV-D did not significantly differ from each other. CONCLUSIONS: SER IV fracture patterns can be unstable with isolated injury to either the superficial or deep deltoid. This challenges the notion that deep deltoid rupture is necessary. Further clinical studies would help quantify the consequences of this instability.

Does Provisional Minifragment Fixation Prevent Compression With Dynamic Compression Plating? A Biomechanical Analysis.

OBJECTIVES: To compare the compressive force generated by a 3.5-mm compression plate with and without provisional fixation using a 2.0-mm minifragment plate. METHODS: Fourth generation composite large humeral sawbones underwent transection and were divided into 2 groups. The first group underwent fixation with a 3.5-mm compression plate; the second group underwent provisional fixation with a 2.0-mm plate followed by definitive fixation using a 3.5-mm plate. Using a load cell, the compressive force generated was measured after insertion of each of 2 eccentrical placed screws and the total compression recorded. RESULTS: There was no difference in the force generated after each successive compression screw (P = 0.59 and 0.58, respectively). Likewise, there was no significant difference in the total compression generated when the preload was accounted for (P = 0.93). CONCLUSION: Provisional minifragment fixation does not have any adverse effect on the forces generated during compression plating. These findings suggest that provisional minifragment plates do not need to be removed before definitive fixation.

Can preoperative radiographs predict hardware complication or fracture displacement after operative treatment of pelvic ring injuries?

INTRODUCTION: Operative fixation of pelvic ring injuries is associated with a high risk of hardware failure and loss of reduction. The purpose of this study was to determine whether preoperative radiographs can predict failure after operative treatment of pelvic ring injuries and if the method of fixation effects their risk. PATIENTS AND METHODS: We conducted a retrospective cohort study of 143 patients with pelvic ring injuries treated with operative fixation at a level 1 trauma center. Preoperative radiographs were examined for the presence of the following characteristics: bilateral rami fractures, segmental or comminuted rami fractures, contralateral anterior and posterior injuries, complete sacral fracture, and displaced inferior ramus fractures. The method of fixation was classified based on the presence of anterior, posterior, or combined anterior and posterior fixation as well as whether or not posterior fixation was performed at a single or multiple sacral levels. Post-operative radiographs were examined for hardware failure or loss of reduction. RESULTS: Twenty-one patients (14.7%) demonstrated either hardware complication or fracture displacement within 6 months of surgery. Male sex was associated with a decreased risk of hardware complication (OR 0.11 [0.014, 0.86]; p=0.03). Posterior pelvic ring fixation at multiple sacral levels was associated with a decreased risk of fracture displacement (OR 0.21 [0.056, 0.83]; p=0.02). We were unable to demonstrate a significant association between preoperative radiographic characteristics and risk of hardware failure or fracture displacement. CONCLUSION: Our study demonstrates that both gender and the method of posterior fixation are associated with hardware failure or displacement.

Deltoid ligament repair reduces and stabilizes the talus in unstable ankle fractures.

INTRODUCTION: Treatment of supination external rotation type IV (SER-IV) ankle injuries has focused on reduction and fixation of the fibula and syndesmosis (ORIF), not repair of the deltoid ligament. METHODS: Twenty-one ankles were analyzed with a motion capture system. Uninjured ankles were stressed and compared to ankles with SER-IV injuries, then with ORIF, and finally ORIF and deltoid repair. RESULTS: After deltoid ligament repair, talar coronal and axial rotation normalized to the uninjured state and were significantly reduced compared to ORIF alone. DISCUSSION: Deltoid ligament repair after an SER-IV ankle injury can help directly reduce and stabilize the tibiotalar joint.

Biomechanical Analysis of Instability in Rotational Distal Fibula Fractures (OTA/AO 44-B1) With an Intact Deltoid Ligament.

OBJECTIVES: To biomechanically analyze instability in supination external rotation (SER) II/III patterns. METHODS: Nineteen cadaver legs were tested in a mechanical jig. One, 2, 3, and 4 Nm of external rotation were applied to intact ankles, SER II injuries, and SER III injuries. The talar position relative to the tibia was recorded using 3D motion tracking. Change from the unloaded state in each condition and the torque level was calculated. Results were analyzed using analysis of variance with post hoc paired t tests. RESULTS: SER II showed statistically significant differences from the intact state with coronal translation (2, 3, and 4 Nm), sagittal translation (1 and 2 Nm), axial rotation (1, 2, 3, and 4 Nm), and coronal rotation (3 and 4 Nm). SER III showed statistically significant differences from the intact state with coronal translation (2, 3, and 4 Nm), sagittal translation (1, 2, and 3 Nm), axial rotation (1, 2, 3, and 4 Nm), and coronal rotation (3 and 4 Nm). SER II and SER III differed significantly from each other with coronal translation (1, 2, and 3 Nm), axial rotation (2, 3, and 4 Nm), and coronal rotation (1, 3, and 4 Nm). CONCLUSION: Instability in SER injuries has only been described with coronal translation and suggests that deltoid rupture is necessary. Our data demonstrate instability in SER II/III in sagittal translation and axial rotation as well as subtle instability in coronal translation. The clinical impact is unclear, but better understanding of long-term sequelae of this instability is needed.

Glucosamine supplementation demonstrates a negative effect on intervertebral disc matrix in an animal model of disc degeneration.

STUDY DESIGN: Laboratory based controlled in vivo study. OBJECTIVE: To determine the in vivo effects of oral glucosamine sulfate on intervertebral disc degeneration. SUMMARY OF BACKGROUND DATA: Although glucosamine has demonstrated beneficial effect in articular cartilage, clinical benefit is uncertain. A Centers for Disease Control report from 2009 reported that many patients are using glucosamine supplementation for low back pain, without significant evidence to support its use. Because disc degeneration is a major contributor of low back pain, we explored the effects of glucosamine on disc matrix homeostasis in an animal model of disc degeneration. METHODS: Eighteen skeletally mature New Zealand White rabbits were divided into 4 groups: control, annular puncture, glucosamine, and annular puncture + glucosamine. Glucosamine treated rabbits received daily oral supplementation with 107 mg/d (weight based equivalent to human 1500 mg/d). Annular puncture surgery involved puncturing the annulus fibrosus of 3 lumbar discs with a 16-gauge needle to induce degeneration. Serial magnetic resonance images were obtained at 0, 4, 8, 12, and 20 weeks. Discs were harvested at 20 weeks for determination of glycosaminoglycan content, relative gene expression measured by real time polymerase chain reaction, and histological analyses. RESULTS: The magnetic resonance imaging index and nucleus pulposus area of injured discs of glucosamine treated animals with annular puncture was found to be lower than that of degenerated discs from rabbits not supplemented with glucosamine. Consistent with this, decreased glycosaminoglycan was demonstrated in glucosamine fed animals, as determined by both histological and glycosaminoglycan content. Gene expression was consistent with a detrimental effect on matrix. CONCLUSION: These data demonstrate that the net effect on matrix in an animal model in vivo, as measured by gene expression, magnetic resonance imaging, histology, and total proteoglycan is antianabolic. This raises concern about this commonly used supplement, and future research is needed to establish the clinical relevance of these findings.