A Predictive Model to Identify Treatment-related Risk Factors for Odontoid Fracture Nonunion Using Machine Learning.

STUDY DESIGN: Multicenter retrospective analysis of routinely collected data. OBJECTIVE: The underlying aim of this study was to identify potential treatment-related risk factors for odontoid fracture nonunion while accounting for known patient- and injury-related risk factors. SUMMARY OF BACKGROUND DATA: Type II and III odontoid fractures represent the most common cervical spine fracture in elderly patients and are associated with a relatively high nonunion rate. The management of odontoid fractures is controversial and treatment strategies range from conservative treatment to extensive surgical stabilization and fusion. METHODS: A total of 415 individuals who sustained odontoid fracture and were treated in either of four tertiary referral centers in Austria and Germany were included in the study. We included the following potential contributing factors for fracture nonunion in cross-validated extreme gradient boosted (XGBoost) and binary logistic regression models: age, gender, fracture displacement, mechanism of injury (high vs. low energy), fracture classification (Anderson II vs. III), presence of comorbidities (Charlson comorbidity index), and treatment (conservative, anterior screw fixation with one or two screws, posterior C1/C2 spondylodesis, cervico-occipital C0-C4 fusion). RESULTS: In our cohort, 187 (45%) had radiologically confirmed odontoid nonunion six months postinjury. The odds for nonunion increase significantly with age, and are lower in type III compared to type II fractures. Also, odds for nonunion are significantly lower in posterior C1/C2 spondylodesis, and C0-C4 fusion compared to conservative treatment. Importantly, odds are not statistically significantly lower in the group treated with anterior screw fixation compared to conservative treatment. The factors gender, fracture displacement, mechanism of injury, and the presence of comorbidities did not produce significant odds. CONCLUSION: Higher age, type II fractures, and conservative treatment are the main risk factors for odontoid nonunion. Anterior screw fixation did not differ significantly from conservative treatment in terms of fracture union. LEVEL OF EVIDENCE: 3.

Internal Fixation of Garden Type III Femoral Neck Fractures with Sliding Hip Screw and Anti-Rotation Screw: Does Increased Valgus Improve Healing?

Background and Objectives: The aim of this study was to compare the effect of valgus versus anatomic reduction on internal fixation of Garden type III femoral neck fractures using the sliding hip screw (SHS) and anti-rotation screw (ARS) regarding the radiographic and therapeutic outcome. Patients and Methods: A retrospective case-controlled study was performed in a level I trauma center. All patients between 2006 and 2020 aged younger than 70 years with a Garden type III femoral neck fracture and a Kellgren-Lawrence score under grade III stabilized using SHS and ARS were identified. One-hundred and nine patients were included, with a group distribution of sixty-eight patients in group A (anatomic reduction) and forty-one patients in group B (valgus reduction). Results: Mean age was 55 years, and the mean Kellgren-Lawrence score was 1 in both groups. Mean femoral neck angle was 130.5 ± 3.8° in group A and 142.8 ± 4.3° in group B (p = 0.001), with an over-correction of 12° in group B. Tip-apex distance was 10.0 ± 2.8 mm in group A versus 9.3 ± 2.8 mm in group B (p = 0.89). Healing time was 9 weeks in group A compared to 12 weeks in group B (p = 0.001). Failure rate was 4.4% in group A and 17.1% in group B (p = 0.027). Conclusions: Anatomic reduction of Garden type III femoral neck fractures in patients younger than 70 years treated using SHS and ARS resulted in significantly lower failure rates and shorter healing times than after valgus reduction. Therefore, it can be recommended to achieve anatomic reduction.

Clinical and radiological evaluation of thoracic spine fractures with or without sternal fracture: is there a need for ventral stabilization?

OBJECTIVE: The treatment of thoracic spine (TS) fractures with additional sternal fractures compared to TS fractures without sternal fractures is discussed controversionally, because in some studies it was stated that sternal fractures decrease the thoracic stability. We hypothesized that both types of fractures can be treated the same way by posterior stabilization alone. METHODS: A total number of 69 patients with thoracic fractures, with or without additional sternal fractures, were examined, regarding the angle of kyphosis after fracture, postoperatively and after 6 and 12 months. We also recorded the outcome using the Odom's score and the time until patients returned to work and the activity level. RESULTS: It was found that the angle of kyphosis was nearly physiological after stabilization in both groups and a loss of reduction after 1 year was also comparable, either in the patients suffering from the additional sternal fracture or not. In addition, the Odom's score and the time until return to work and the activity level were comparable in both groups. CONCLUSION: We did not find any arguments to preserve additional anterior stabilization or reasons for different treatment strategies either additional sternal fractures occur in thoracic spine fractures or not.

Functional outcome after traumatic cervical spinal cord injury is superior in adolescents compared to adults.

OBJECTIVE: Determining differences in neurological and functional outcome between adolescents and adults after acute traumatic spinal cord injury (SCI). DESIGN: Retrospective, multi-center case-control study. METHODS: 100 cases of patients under 18 years at accident with acute traumatic cervical SCI admitted to SCI centers participating in the European Multi-center study about SCI (EMSCI) between January 2005 and April 2016 were reviewed. According to their age at accident, age 13 to 17, patients were selected for the adolescent group. After applying in- and exclusion criteria 32 adolescents were included. Each adolescent patient was matched with two adult SCI patients for analysis. OUTCOME MEASURES: ASIA Impairment scale (AIS) grade, neurological, sensory, motor level, total motor score, and Spinal Cord Independence Measure (SCIM III) total score. RESULTS: Mean AIS conversion, neurological, motor and sensory levels as well as total motor score showed no significantly statistical difference in adolescents compared to the adult control group after follow up of 6 months. Significantly higher final SCIM scores (p < 0.05) in the adolescent group compared to adults as well as a strong trend for a higher gain in SCIM score (p < 0.061) between first and last follow up was found. CONCLUSIONS: Neurological outcome after traumatic cervical SCI is not superior in adolescents compared to adults in this cohort. Significantly higher SCIM scores indicate more functional gain for the adolescent patients after traumatic cervical SCI. Juvenile age appears to be an independent predictor for a better functional outcome.

Biomechanical evaluation of subtalar fusion: the influence of screw configuration and placement.

Common surgical procedures for subtalar fusion include joint resection, autologous bone grafting, and osteosynthesis with screws in a parallel screw configuration. Although fusion is a routine procedure, the reported rates of nonunion have been high. The present study assessed different screw configurations in terms of their rotational and bending stability in an artificial bone model and cadaver bone. Arthrodesis was always performed with 2 screws. Three different screw configurations were tested: parallel, counter-parallel, and a delta configuration. Two different screw designs were used: a cannulated, partially threaded screw (6.5-mm and 8.0-mm diameter) and a solid screw with a different thread design. Eight experimental groups were investigated as pilot studies in artificial bones and then 3 groups in cadaver bones. The parameters were the primary stiffness and deflection of the construct for loads simulating the internal-external rotation and supination-pronation. Delta positioning of the screws resulted in the greatest biomechanical stiffness and the lowest degrees of deflection of the arthrodesis in the artificial bones and cadaver bones. Increasing the screw diameter from 6.5 to 8.0 mm resulted in no additional stability of the arthrodesis in the artificial bones. The results of the present study have indicated that the delta configuration for arthrodesis results in the greatest construct stiffness and lower relative deflection between the talus and calcaneus in the positions tested.

Biomechanical comparison of intramedullar versus extramedullar stabilization of intra-articular tibial plateau fractures.

BACKGROUND: Fractures of the proximal tibia occur very often and are a great challenge for trauma surgeons to stabilize. Although locked nails were developed to stabilize these fractures, this technique has not been sufficiently investigated. The purpose of this study was to biomechanically assess the stability of locked intramedullary nailing compared to locked plating. METHODS: 16 fresh frozen human cadaveric tibiae were osteotomized in the meta-diaphyseal intersection with an osteotomy gap of 10 mm and a single osteotomy through the medial epicondyle to simulate a 41-C.2 fracture. Stabilization was performed with an angle stable locked Targon-TX nail (n = 8) and two additional canulated screws. The other testing group (n = 8) was treated with two canulated screws and a five-hole LCP-PLT. The bones were tested in a cyclic testing protocol with increasing loads under compression and a load sharing of 60 % through the medial tibial plateau and 40 % to the lateral side. Stiffness and fracture gap movement were measured and failure mode was assessed. RESULTS: No significant differences were found between the two implants regarding load until failure. The stiffness of the intramedullary nailing group (927 N/mm) was statistically significantly higher than the stiffness of the plating group (564 N/mm). No differences were found for fracture gap movement in the z-axis. However, differences were found for dislocation of the proximal-lateral and proximal-medial fragments, with absolute values of 0.099 mm in the plate group and 0.66 mm in the nailing group at 800 N. Prior to failure, fracture gap movement was 0.22 mm for the plating group and 1.66 mm for the nailing group, a difference that was also statistically significantly different. The nailing group failed by screw cut-out while the plating group failed by screw breakage. CONCLUSION: Nailing of proximal tibia fractures leads to a stiffer implant-bone construct than plating. Since no adverse effects were found after nailing it seems to be a good alternative to plating for intra-articular proximal tibia fractures, especially in patients with soft tissue problems.

Fat extravasation due to unreamed and experimentally reamed intramedullary nailing of the sheep femur.

AIM: To compare systemic fat extravasation in unreamed and experimentally reamed nailing. METHODS: An osteotomy was created in the proximal third of the femoral shaft in 16 sheep, and intramedullary pressure increase and fat extravasation were monitored for the two nailing techniques. RESULTS: The highest intramedullary pressures, median 2700 mm Hg, and highest percentages of fat extravasation, peaking at almost 90% of fat, were found for the unreamed nailing technique. The values for the reamed group were significantly lower. CONCLUSIONS: The extravasation of intramedullary fat can be attributed to the great increase in intramedullary pressure that occurs during unreamed nailing. Correctly performed intramedullary reaming with the new reaming system produces lower pressures and much less systemic fat extravasation, reducing the risk for fat embolism.