Features of intra-hamate vascularity and its possible relationship with avascular risk of hamate fracture

Minimally invasive percutaneous screw internal fixation under robot navigation for the treatment of a hamate bone fracture

PURPOSE

Hamate fractures are rare fractures of the wrist and there is still no consensus on the optimal treatment for these fractures, especially hook of hamate fractures. Herein, the authors present a case study of a series of patients who were treated with closed reduction and minimally invasive percutaneous fixation under robot navigation.

METHODS

This retrospective study reviewed 14 patients who had nondisplaced or minimally displaced hamate fractures on computerized tomography images and were treated using the treatment in our centre from November 1, 2019, to October 31, 2022. At the final follow-up, the flexion-extension and radial-ulnar range of motion of the wrist were measured, and the grip strength and pinch strength were measured. The pain of the wrist was assessed using the visual analogue scale (VAS). The Mayo wrist score reflected the recovery of the wrist.

RESULTS

The mean total operative duration was 40.1 min. All the fractures showed union at a mean of 3.0 months. At a mean follow-up of 23.3 months (range 6-36 months), the mean VAS score was 0.7, the average Mayo wrist score was 95, and the mean pinch strength and grip strength were 11.3 and 38.7 kg, respectively. The flexion-extension arc was 138.3°, the mean radial and ulnar deviation arc was 63.8°, and the mean pronation-supination arc was 172.3°. And the time of return to the original occupation was mean 4 months (3~6 months). There were no complications, such as infection or nerve paralysis.

CONCLUSIONS

This study suggests that nondisplaced or minimally displaced hamate hook fractures can be successfully treated by closed reduction and internal fixation with a headless compression screw with the assistance of robot navigation, and the small fragment of fracture can be accurately fixed with minimal iatrogenic injury.

The morphologic and morphometric features of the triquetrum

Fractures of the triquetrum are the second most common form of isolated carpal bone fracture after the scaphoid. However, data on triquetrum morphology and morphometry are sparse. The aim of this study was to describe the morphology of triquetrum using anatomical landmarks, evaluate its morphometric features, and determine its vascular entry points. The morphological and morphometrical features of 87 adult dry triquetral bones (39 left, 48 right) were determined by measuring length, width and thickness. The number and locations of nutrient foramina wider than 0.5 mm were recorded. Mean length, width and thickness were 17.37 mm (range, 14.26-22.13), 12.65 mm (range, 10.37-15.85) and 11.41 mm (range, 8.98-18.23), respectively. The facet articulating with the pisiform was oval in 40 bones, round in 8 and amorphous (neither round nor oval) in 39. The mean length of the interarticular ridge was 7.09 ± 0.9 mm. The mean number of nutrient foramina was significantly greater on the dorsal than on the other aspects. The dorsal predominance of nutrient foramina makes the bone weaker in the dorsal region, which could explain why fractures are more common in this region. Also, the dorsal aspect is rich in blood supply, which could explain why avascular necrosis is less common in triquetral fractures. As most of the vascularization is on the dorsal side, there is need for caution when performing triquetrum surgery. LEVEL OF EVIDENCE: Level 2.

Hook of Hamate Fractures

Hook of hamate fractures are uncommon injuries with unclear prevalence. Classic presenting symptoms include volar-ulnar hand/wrist pain and weakness in grip, with possible ulnar nerve paresthesias. Patient factors, such as activity level and desired return to work/sport, shape the most appropriate treatment regimen although excision of the hook has been adopted by most surgeons. Overall, once patients receive the correct diagnosis and are treated, good outcomes with high satisfaction rates are expected.

Evaluation and Management of Carpal Fractures Other Than the Scaphoid

Fractures of the carpus can be debilitating injuries and often lead to chronic pain and dysfunction when not properly treated. Although scaphoid fractures are more common, fractures of the other carpal bones account for nearly half of all injuries of the carpus. Often missed on initial presentation, a focused physical examination with imaging tailored to the suspected injury is needed to identify these fractures. In addition to plain radiographs, advanced imaging such as CT and MRI are helpful in diagnosis and management. Treatment of carpal fractures is based on the degree of displacement, stability of the fracture, and associated injuries. Those that require surgical fixation often affect the congruency of the articular surfaces, are unstable, are at risk for symptomatic nonunion, are associated with notable ligamentous injury, or are causing nerve or tendon entrapment. Surgical strategies involve percutaneous Kirschner wires, external fixation, screws and/or plates, excision, or fusion for salvage. Owing to the intimate articulations in the hand, small size of the carpal bones, and complex vascular supply, carpal fracture complications include symptomatic nonunion, osteonecrosis, and posttraumatic arthritis.