The inter-individual anatomical variation of the trochlear notch as a predisposition for simple elbow dislocation

Purpose Besides the multi-layered capsule–ligamentous complex of the elbow joint the high bony congruence in the ulnohumeral joint contributes to elbow stability. Therefore, we assume that specific anatomical configurations of the trochlear notch predispose to dislocation. In case of ligamentous elbow dislocation both conservative and surgical treatment is possible without a clear treatment algorithm. Findings of constitutional bony configurations could help deciding for the best treatment option. Methods In this retrospective matched-pair analysis we compared MRI imaging from patients sustaining a primary traumatic elbow dislocation (instability group) with patients suffering from chronic lateral epicondylitis (control group), treated between 2009 and 2019. Two independent observers measured different anatomical landmarks of the trochlear notch in a multiplanar reconstructed standardized sagittal trochlear plane (SSTP). Primarily, opening angle and relative depth of the trochlear notch were determined. After adjustment to the proximal ulnar rim in the SSTP, coronoid and olecranon angle, the articular angle as well as the ratio of the tip heights of the trochlear notch were measured. Results We compared 34 patients in the instability group (age 48 ± 14 years, f/m 19/15) with 34 patients in the control group (age 47 ± 16 years, f/m 19/15). Instability group showed a significantly larger opening angle (94.1° ± 6.9° vs. 88.5° ± 6.9°, p = 0.0002), olecranon angle (60.9° ± 5.3° vs. 56.1° ± 5.1°, p < 0.0001) and articular angle (24.7° ± 6.4° vs. 22.3° ± 5.8°, p = 0.02) compared to the control group. Measuring the height from the coronoid (ch) and olecranon (oh) tip also revealed a significantly larger tip ratio (tr = ch/oh) in the instability group (2.7 ± 0.8 vs. 2.2 ± 0.5, p < 0.0001). The relative depth (61.0% ± 8.3% vs. 62.7% ± 6.0%, p = 0.21) of the trochlear notch as well as the coronoid angle (32.8° ± 4.5° vs. 31.7° ± 5.2°, p = 0.30) showed no significant difference in the instability group compared to the control group. The interrater reliability of all measurements was between 0.83 and 0.94. Conclusion MRI of patients with elbow dislocation show that there seems to be a bony anatomical predisposition. According to the results, it seems reasonable to include predisposing bony factors in the decision-making process when surgical stabilization and conservative treatment is possible. Further biomechanical studies should prove these assumptions to generate critical bony values helping surgeons with decision making. Level of evidence III.

Open reduction of an old and unreduced posterior elbow dislocation

The old unreduced elbow dislocation is not very frequent, but when it is found, it is a challenge for every surgeon. We present a case of 65 years old man who came to the hospital with a dislocated elbow. After the first attempt to reduce, the elbow was mobilized in sling for 2 weeks, but during a small effort, the joint dislocated again. Another two orthopedic reduction were tried, followed by cast immobilization, but the elbow dislocated again. The patient presented in our service after two months from the injury with stiff joint in a vicious position. On imagistic examinations (Rx, CT, MRI), it was found comminuted fracture of coronoid process, posterior dislocation of olecranon and both collateral ligaments were torn. An open reduction was performed during which the joint surface was cleaned up, the anterior capsule was reattached to the coronoid process with an anchor, and then, collateral ligament was restored with the help of autograft, a gracilis muscle (bone fixed with two anchors). Postoperatively, the patient slowly began to mobilize the elbow with splint protection. After a year, the patient returned for follow-up; the function was completely restored and he had no pain.

Diaphyseal Radius Fracture Associated with Irreducible Head Dislocation. Case Report

Irreducible dislocation of the radial head is an extremely rare lesion, especially in an adult patient. We present a case of diaphyseal radius fracture associated with a posterior elbow dislocation and an irreducible radial head dislocation. After closed reduction of the elbow, we performed open reduction and ostheosynthesis of the radius, and the radial head remained irreducible. We finally found, surrounding the radius, the interposition of the insertion of the biceps, and, after extracting it, we performed the correct reduction of the radial head. Six months after the surgery, the patient presented a full articular balance, with no pain. We have not found any similar case in the literature.