Biomechanical testing of a novel osteosynthesis plate for the ulnar coronoid process

Comparison of buttress plate and cannulated screw in the treatment of anteromedial coronoid fracture with elbow posteromedial rotatory instability

PURPOSE

The purpose of this study is to compare the effect of buttress plate and cannulated screw in the treatment of anteromedial coronoid fracture with posteromedial rotatory instability (PMRI).

METHODS

We retrospectively evaluated patients who were diagnosed with O'Driscoll type 2 fractures combined with elbow posteromedial rotatory instability and underwent surgery for anteromedial coronoid fracture between August 2014 and March 2019. They were divided into buttress plate (n=16) and cannulated screw (n=11) groups. The elbow range of motion, visual analog scale (VAS), Mayo elbow performance score (MEPS), and disabilities of the arm, shoulder, and hand score (DASH) were used for clinical outcome assessment.

RESULT

There were no significant differences in clinical outcomes. However, the surgical time was significantly shorter in cannulated screw group (85.45±4.156) compared to the buttress plate group (93.81±8.863, P=0.008), and the surgical time was associated with internal fixation (P=0.008).

CONCLUSION

Although there was selection of cases in that small fragments were treated with buttress plate and large fragments with cannulated screw, the buttress plate and cannulated screw have comparable functional outcomes on fixation of the anteromedial coronoid fracture with elbow PMRI. The fixation of the anteromedial coronoid fracture with large fragments using the cannulated screw has a shorter operation time.

Morphological characteristics of fractures of the anteromedial facet of the coronoid in posteromedial rotatory instability of the elbow: a three-dimensional CT remodeling study

BACKGROUND

Fractures of the anteromedial facet of the coronoid in posteromedial rotatory instability of the elbow are classified into 3 subtypes based on their location. The purpose of this study was to analyze the fracture morphology of anteromedial facet fractures in their 3 subtypes (anteromedial rim, anteromedial rim + tip, and anteromedial rim + sublime tubercle [±tip]).

METHODS

Three-dimensional computed tomography remodeling was used to evaluate anteromedial facet fractures in a consecutive series of 40 patients, all of whom were affected by posteromedial rotatory instability of the elbow. Characteristics of the fractures, including the number of fragments, size of fragments, plane of the fracture line, and involvement of the sublime tubercle and radial notch, were measured for each subtype of the anteromedial facet fractures.

RESULTS

Each subtype had a typical fracture pattern and distinct size. The fracture subtype 1 showed a single-fragment fracture, subtype 2 showed either a single- or dual-fragment fracture, and subtype 3 showed either a dual- or triple-fragment fracture. The angle between the fracture line and the coronal plane was greatest in subtype 3 fractures. The surface area of the fragment was largest in subtype 3 fractures. The percentages of articular involvement of the sublime tubercle were 0% in subtype 1, 47% in subtype 2, and 79% in subtype 3. The percentages of articular involvement of the radial notch were 0% in subtype 1, 7% in subtype 2, and 8% in subtype 3.

CONCLUSION

Analysis with quantitative 3-dimensional computed tomography showed the characteristic morphology of each subtype of anteromedial facet fracture. Subtype 1 comprised 1 fragment with the smallest fragment size. Subtype 2 was a single- or dual-fragment fracture, the size of which should be considered in the treatment plan. Subtype 3 was a large fragment comprising the sublime tubercle. Our findings are significant because they highlight unique fracture morphology that may help surgeons to distinguish one fracture subtype from another in clinical practice.

No neurovascular damage after creation of an accessory anteromedial portal for arthroscopic reduction and fixation of coronoid fractures

PURPOSE

Arthroscopic reduction and internal fixation for coronoid process fractures has been proposed to overcome limitations of open approaches. Currently, arthroscopy is most frequently used to assist insertion of a retrograde guide wire for a retrograde cannulated screw. The present anatomical study presents an innovative arthroscopic technique to introduce an antegrade guide wire from an accessory anteromedial portal and evaluates its safety and reproducibility.

METHODS

Six fresh-frozen cadaver specimens were obtained and prepared to mimic an arthroscopic setting. The coronoid process was localized and a 0.9 mm Kirschner wire was introduced from an accessory anteromedial portal, located 2 cm proximal to the standard anteromedial portal. At the end of the procedure, a lateral radiograph was taken to verify the Kirschner wire position and open dissection was conducted to evaluate possible damage to neurovascular structures.

RESULTS

The Kirschner wire was drilled without complications in the coronoid process of all six specimens. Damage of the brachial artery, the median nerve, and the ulnar nerve did not occur in any specimen. A corridor between the brachialis muscle, the median intermuscular septum, and the pronator teres could be identified as suitable for the wire passage.

CONCLUSION

This study presents a safe and reproducible technique combining the possibility to introduce a guide wire from the anteromedial part of the coronoid, under direct visual control, with a completely arthroscopic approach. This wire can guide the introduction of a retrograde cannulated screw from the dorsolateral ulna to the tip of the coronoid. This new arthroscopic approach permits to obtain improved visual control over coronoid process fixation, without endangering neurovascular structures.

Arthroscopic reduction and fixation of coronoid fractures with an exchange rod-a new technique

BACKGROUND

The ulnar coronoid process plays a central role in maintaining elbow stability. Some of its fractures were often combined with injury of bone and ligament. Arthroscopy enables perfect visualization to allow anatomical repair.

METHODS

From January 2012 to December 2013, six patients (four males, two females) with a mean age of 26.6 years were treated. The left and right ulnas were involved in two and four patients, respectively. All patients suffered from ipsilateral subluxation of the elbow without associated radial fracture. According to the Regan and Morrey fracture classification and O'Driscoll's classification, two and four patients were classified as type I and type II and as having tip fracture (O'Driscoll type I) and anteromedial fracture (O'Driscoll type II), respectively. Exchange rod technology via the elbow front center approach was used for reduction and fixation of fractures of the coronoid process of the ulna.

RESULTS

Intra- and postoperative X-ray examination showed that the fractures were satisfactorily fixed and that the screw and fracture line were vertical to each other. Follow-ups showed that the fractures had healed well, and the average elbow extension was -2° while the average flexion was 140°. No problems related to pronation or supination, elbow instability, or complications of blood vessels or nerves were reported. The elbows showed excellent results according to the Mayo Elbow Performance Score.

CONCLUSIONS

Arthroscopy using an exchange rod can provide excellent visual exposure of the fractured joints, without the need for a large incision during the anatomical repair. Moreover, it protects the surrounding soft tissue, shows good stability of the components, and allows early rehabilitation exercises.