Microstructural study of the lunate in stage III Kienböck's disease with micro-computed tomography imaging

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

BACKGROUND

The angiography with micro-computed tomography (micro-CT) has been proved its great advantages on investigating the intra-osseous vascularity of carpal bones. But few researches have focused on the intra-hamate vascularity. This study aimed to illustrate the intra-osseous arteries of the hamate and the relationship between the intra-hamate vascularity and the avascular risk of different types of hamate fractures.

METHODS

Six normal cadaveric hamates were investigated with red lead (Pb3O4) micro-CT angiography. The intra-osseous arteries of specimens were clearly enhanced and the three-dimensional model was reconstructed. In order to study the features of the arterial entrances and intra-hamate vascularity, the diameters, quantities, locations of enhanced arteries, and the locations of transversal/proximal pole fracture lines on the body of the hamate were statistically compared. Besides, in order to analyze the relationship between intra-hamate vascularities and different hamate fractures, 127 cases of hamate fractures who presented in our hospital from March 2003 to June 2017 were retrospectively studied.

RESULTS

A total of 94 cases were followed up (range: 4-37 months; mean: 12.4 months) effectively. The overall union rate of hamate fractures was as high as 92.6% (87 of 94 cases), while non-union of fracture on hamate hook was more common (P = 0.031). The arterial entrances were located around the dorsal, volar, radial, ulnar non-articular surfaces of the hamate body and the hook of the hamate. Generally, there were one to two trunk arteries on the volar non-articular surface and one to three trunk arteries on the dorsal non-articular surface. They formed one or two arterial arches, from which some branches were emitted and supplied the proximal parts. The intra-osseous vascularities of the hamate body were generally located in the radial part. The blood supply of the hook was mainly from the volar non-articular surface in most specimens. Hamate fractures could be classified into four types: fractures of the transversal/proximal pole, medial tuberosity, dorsal coronal of the hamate body, and fractures of the hamate hook.

CONCLUSIONS

This study showed new features of intra-hamate vascularity and the results will guide surgeons to reduce the vascular damage during the hamate fracture operations. The fracture lines of different types of hamate fractures may disrupt the intra-hamate arteries. The intra-hamate vascularities will have different influences on the avascular risks of different hamate fractures.

Kienböck's disease: Where do we stand?

Avascular necrosis of the lunate, commonly known as Kienböck's disease is a disorder that can lead to carpal collapse and the need for surgeries, which can stabilize the wrist. There are different associations with the disease but the exact etiology is unknown. Kienböck's disease is believed to result from mechanical and vascular factors in genetically predisposed individuals. The newer classification based on advanced wrist arthroscopy and MRI help in a better understanding of the disease, early diagnosis, and treatment. A review of recent literature regarding newer treatment options has shown good results in the early stages of osteonecrosis. This article intends to review an update on the etiopathogenesis, classification, and the current advanced treatment options.

Superselective angiography of the wrist in patients with Kienböck's disease

BACKGROUND

Microvascular problems like increased intraosseous pressure or venous congestion may influence the development of Kienböck's disease. We examined if wrist position modifies the blood flow in the nutrient vessels.

METHODS

Retrospective analysis of 17 patients with Kienböck's disease who had a superselective microangiography of the radial, ulnar and interosseous artery in different wrist positions under general anaesthesia. We analysed the data with Fisher's exact and Wilcoxon-test.

RESULTS

We found vessels that entered the bone, that ended at the bone edge, and that supplied a vascular plexus. The origins were the anterior interosseous artery in 10 of 17 cases, the radial artery in seven cases, and the ulnar artery in five cases. Movement of the wrist could reduce or stop the blood flow. Type of lunate configuration showed no significant influence on the blood supply in neutral position.

CONCLUSION

The radial, ulnar, and anterior interosseous artery contribute to the vascular supply of the lunate bone in different combinations. Wrist movement can reduce blood flow to the lunate bone.

New findings about the intrascaphoid arterial system

We investigated the intraosseous arteries of six normal cadaveric scaphoids using red lead injection and three-dimensional reconstruction with micro-computed tomography. The arterial entrances were generally located around the dorsal ridge, the insertion of the scaphocapitate ligament and the radial part of the radioscaphocapitate ligament. Two to three trunk arteries entered the scaphoid on dorsal ridge at the level of the waist. The distal part of the scaphoid was mainly supplied by arteries from the waist. The blood supply of about 40% of proximal part of the scaphoid was poor. The blood supply from the scaphoid dorsal ridge plays an important role, not only for the proximal part of the scaphoid, but also for the waist and even the distal pole. The intrascaphoid arterial pattern may be contributory to nonunion, especially in proximal pole fractures.

Three-dimensional Intralunate Arteries Visualization with Red Lead (Pb3O4) Angiography

BACKGROUND

The etiology of Kienböck's disease is controversial, and the blood supply is a possible pathogenic factor. The red lead (Pb3O4) angiography with micro-computed tomography (micro-CT) of lunate to investigate intralunate arteries has rarely been reported. This study aimed to investigate a new, reasonable, and simplified technique to study the intraosseous arterial pattern of normal lunates.

METHODS

This study investigated the intraosseous arterial pattern of six normal cadaveric lunates through Pb3O4injection and three-dimensional reconstruction with micro-CT. The intraosseous arteries of all specimens were clearly enhanced. The data of enhanced arteries and nutrient foramina were shown as median (Q1, Q3) and analyzed with Wilcoxon signed-rank test.

RESULTS

The mean number of total nutrient foramina was 2.00 (1.75, 2.00) on the palmar side and 3.50 (2.50, 4.25) on the dorsal side. The number with enhanced arteries on the palmar side was 1.00 (0.75, 2.00) and on the dorsal side was 3.50 (1.75, 4.00). There were no significant differences between the number of nutrient foramina on the palmar and dorsal sides of the lunates, no matter the total number or enhanced arteries. The intraosseous arterial pattern in normal lunates can be classified into three types: the dominate stems from the palmar side, from the dorsal side, and from both sides with anastomosis.

CONCLUSIONS

The Pb3O4angiography with micro-CT is a simplified, quicker, and reliable method to study intraosseous arteries.