Monteggia fractures initially referred specifically to fractures of the proximal third of the ulna combined with anterior dislocation of the radial head. In 1967, Bado categorized this injury into four types based on the direction of radial head dislocation and whether there was an associated fracture of the radial shaft. Among these types, Bado II, involving posterior dislocation of the radial head in Monteggia injuries, is the most common and complex. Subsequently, Jupiter and others further subdivided Monteggia injuries with posterior dislocation of the radial head based on the location of the ulnar fracture. Most scholars acknowledge that a series of injuries involving proximal ulnar fractures combined with posterior dislocation of the radial head, radial head fractures, or coronoid process fractures should be collectively referred to as posterior Monteggia fracture-dislocations. Dong Jingming and others further proposed that classic Monteggia fractures involve ulnar fractures with a dislocation of the proximal radioulnar joint. When combined with posterior dislocation of the radial head, it is termed posterior Monteggia fracture, whereas those without dislocation of the proximal radioulnar joint are termed post-ulnar proximal fractures with dislocation. Due to the various complex patterns of fractures and dislocations involving the proximal ends of the ulna and radius in posterior Monteggia fractures, it is crucial to understand the extent and nature of the injury. Only by restoring the bony structure and elbow joint stability can satisfactory clinical outcomes be achieved.

To investigate the clinical features and operative effect of posterior Monteggia fracture.

A retrospective analysis was conducted on data from 19 adult patients with posterior Monteggia fractures treated between January 2016 and January 2020. Among them were 13 males and 6 females, with an average age of (46.8±15.6) years (ranging from 21 to 69 years old). Anatomical locking plates were used for ulnar fractures, while internal fixation or replacement was performed for radial head fractures. Coronoid process fractures were fixed using screws or mini-plates, and repair with anchor nails was employed for injuries to the medial and lateral collateral ligaments. The patients' general information and the morphological characteristics of their fractures and dislocations were analyzed, followed by postoperative follow-up to assess elbow joint function.

Jupiter IIA/IID type accounted for 89% (17 cases), involving combined injuries of the olecranon of the ulna, coronoid process, radial head fractures with dislocation, elbow dislocation, and lateral collateral ligament tear. All patients were followed up for an average of (20.8 ± 5.3) months (ranging from 11 to 37 months). The average flexion of the elbow joint was (117.1 ± 18.5) ° (ranging from 90° to 140°), while the average extension was (18.2 ± 12.7) ° (ranging from 5° to 45°). The average pronation was (54.2 ± 19.5) ° (ranging from 10° to 70°), and the average supination was (62.1 ± 20.4) ° (ranging from 10° to 80°). The Broberg-Morrey elbow joint functional system score averaged (79.8 ± 11.5) points (ranging from 57 to 93 points). Seven cases (37%) experienced postoperative heterotopic ossification, resulting in significantly lower elbow joint mobility and functional scores compared to patients without heterotopic ossification (P < 0.05) .

The injuries classified as Jupiter IIA/IID often involve combined injuries, including olecranon and coronoid process fractures, radial head fractures with dislocation, elbow dislocation, and lateral collateral ligament tears. Accurately identifying these injury features and employing appropriate surgical treatments can yield favorable outcomes.