Medial Epicondyle Fractures: Biomechanical Evaluation and Clinical Comparison of 3 Fixation Methods Used in Pediatric Patients

Screw Diameter and Use of a Washer Affect Symptomatic Implant Removal Rates in Pediatric Medial Epicondyle Fractures

OBJECTIVE

Medial epicondyle fractures are a common pediatric injury. When operative, cannulated partially threaded screws, with or without a washer, are commonly utilized. These implants may need to be removed after full healing if symptomatic. There is mixed evidence regarding the influence of a washer on rates of implant removal, and the influence of screw size has not been studied. We aim to determine the rate of symptomatic deep implant removal for each fixation type and identify factors associated with the need for removal.

METHODS

This was an IRB-reviewed, retrospective, case-cohort study. Patients treated at our institution between January 1, 2004 and December 31, 2019, age 18 years old or younger, with a medial epicondyle fracture managed operatively with 4.0 or 4.5 mm cannulated screws with or without washers were included. Patients with multiple operative ipsilateral elbow fractures and those who underwent implant removal for reasons other than pain or irritation were excluded. Removal rates were compared between screw sizes (4.0 vs 4.5 mm), as well as with and without a washer using a Cox proportional hazards model.

RESULTS

In total, 151 patients met the inclusion criteria, 54 with symptomatic hardware removed and 97 without symptomatic hardware removed. A significantly higher number of patients treated with 4.5 mm screws compared with 4.0 mm screws underwent removal of symptomatic deep implants (50% vs 30%, P = 0.033). In a multivariable Cox regression model adjusting for age and ulnar nerve status, when no washer was used, the hazard ratio (HR) for symptomatic hardware removal for 4.5 mm screws was 2.92 times the HR for 4.0 mm screws (95% CI: 1.35-6.29). When a 4.0 mm screw was used, the HR for symptomatic hardware removal for a washer was 3.24 times the HR without a washer (95% CI: 1.53-6.84).

CONCLUSION

Implant removal rates are influenced by screw size and the use of a washer. These results may help guide implant choice and counsel families regarding the rate of symptomatic implant removal.

LEVEL OF EVIDENCE

Level III-therapeutic level, case-control study.

Development and validation of a specialized system for self-tapping medical bone screw testing

A specialized system for accurate self-tapping medical bone screw testing is developed, fully meeting the requirements of ASTM F543-A4 (YY/T 1505-2016). The onset of self-tap is identified automatically according to a change in the slope of the torque curve. Precise load control is applied to determine the self-tapping force accurately. A simple mechanical platform is embedded to ensure the automatic axial alignment of a tested screw with the pilot hole in a test block. In addition, comparative experiments are conducted on different self-tapping screws to verify the system's effectiveness. By the automatic identification and alignment method, both torque curves and axial force curves for each screw exhibit significant consistency. The self-tapping time point derived from the torque curve agrees well with the turning point of the axial displacement curve. The determined self-tapping forces' mean values and standard deviations are both small, which are proved to be effective and accurate in the insertion tests. This work contributes to improving the standard test method for accurate determination of the self-tapping performance of medical bone screws.

Clinical study of suture anchors in the treatment of radial head fractures

BACKGROUND

This study aimed to analyze and study the clinical effect of suture anchors in the treatment of radial head fractures (RHFs).

METHODS

A total of 11 patients (five male and six female) with RHFs who were treated from March 2016 to June 2021 were included in this study. They were 17-61 (average 38.5) years old. In terms of the Johnston-Mason classification, two cases were type II, seven cases were type III, and two cases were type IV. All patients were treated with open reduction and anchor internal fixation.

RESULTS

All 11 patients were followed up, all incisions healed by first intention, and the duration of follow-up was 14-20 months. The average operation time was 40 ± 15 min. The clinical healing time was 4-6 (average 5) weeks. No patients had any complications, such as traumatic arthritis, malunion, nerve injury, joint stiffness, or incision infection. The clinical effects were evaluated according to the Mayo Elbow Performance Score. The scores of all 11 cases were 90-95, all excellent.

CONCLUSION

The application of suture anchor internal fixation in the treatment of RHFs has the advantages of accurate reduction, no need for a secondary operation to remove the fixation materials, less trauma, fewer complications, good fracture healing, and good recovery of elbow extension, flexion, and rotation functions.

Changes in the management of pediatric medial humeral epicondyle fractures with and without associated elbow dislocation

Purpose The optimal management of medial humeral epicondyle fractures continues to be debated since decades. This single center study analyzes changes and optimizations of treatment over an observation period of 16 years and reports the results. Materials and Methods Retrospective analysis of all patients treated with a medial humeral epicondyle fracture between 2005 and 2020 at our institution. Results Ninety-six patients (mean 9.3 years, range 1 - 15) were included in the study. In 25 cases (26 %), the fracture was associated with an elbow dislocation. Most patients received surgical treatment (83.3 %), whereas 17.7 % were treated nonoperatively. Surgical treatment consisted of open reduction and fixation with compression screw (n = 44 steel, n = 2 absorbable), K-wire (n = 30), a combination of screw/K-wire (n = 2), or a PDS suture (n = 1). Compression screws have been used significantly more often in the latter half of the study period (p = 0.006). Patients were immobilized in a long arm cast for 29 days (range 11 - 50). Eleven surgically treated patients were early mobilized in an elbow orthosis. After a mean follow up of 7.6 months [2 - 61), Mayo elbow performance index (MEPI) outcome was excellent in all 96 patients. Loss of elbow movement (LOM) was found to be mild in 30 and moderate in 15 patients. LOM was found to be associated with surgical treatment (p = 0.001), and with concomitant elbow dislocations (p = 0.29). One pseudarthrosis occurred after conservative treatment. A persistence of ulnar nerve palsy or recurrent joint instability has not been described. Conclusion Most children with medial humeral epicondyle fractures nowadays undergo surgery. Screw osteosynthesis represents the increasingly preferred method in order to prevent joint instability or non-union, and to allow shorter immobilization duration. Overall results after medial epicondyle fractures are good.

Is Computed Tomography Necessary for Diagnostic Workup in Displaced Pediatric Medial Epicondyle Fractures?

This study aimed to compare the treatment outcomes and complications between operatively and nonoperatively treated medial epicondyle fractures with displacement of >5 mm as accurately measured on three-dimensional computed tomography (3D CT). We retrospectively reviewed 77 patients who had isolated medial epicondylar fractures with displacement of >5 mm. The mean age at injury was 11.4 years. Patients were assigned to one of two groups: 21 patients treated nonoperatively and 56 patients treated surgically. Additionally, patients treated operatively were divided into two subgroups according to fixation method; 31 patients underwent internal fixation with K-wires and 25 patients underwent internal fixation with a screw. Radiological and functional outcomes were compared among the three groups. Although the bony union rate was significantly higher in patients treated operatively compared to patients treated non-operatively (96.4% vs. 23.8%, p < 0.001), there were no significant differences in functional outcomes between the two groups. In the nonoperative group, three patients underwent osteosynthesis for symptomatic nonunion. There were no significant differences in radiological and functional outcomes between the two subgroups divided by fixation method. In a pediatric medial epicondylar fracture with a displacement of >5 mm as accurately measured on 3D CT, despite the difference in union rate, there was no difference in functional outcomes between operative and nonoperative treatment. Performing CT only to measure the fracture displacement in obviously displaced medial epicondylar fracture is not considered as a part of the “necessary” diagnostic workups.