Computer-assisted Surgery for Scaphoid Fracture

The computer-assisted surgery (CAS)has significantly improved the accuracy, reliability and outcomes of traumatic,spinal,nerve surgery and many other operations with a less invasive way.The application of CAS for scaphoid fractures remains experimental.The related studies are scanty and most of them are cadaver researches.Some intrinsic defects from the registration procedure,scan and immobilization of limbs may inevitably result in deviations. Some deviations become more obvious with operations of small bones (such as scaphoid)although they are acceptable for spine and other orthopedic surgeries.We reviewed the current literatures on the applications of CAS for scaphoid operation and summarized technical principles,scan and registration methods,immobilization of limbs and their outcomes.On the basis of the data,we analyzed the limitations of this technique and envisioned its future development.

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

Background： The etiology of Kienb-ck＇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 Pb3O4 injection 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 Pb3O4 angiography with micro-CT is a simplified, quicker, and reliable method to study intraosseous arteries.

Surgical Fixation of Fourth and Fifth Metacarpal Shaft Fractures with Flexible Intramedullary Absorbable Rods： Early Clinical Outcomes and Implications

Background： To avoid the irritation of tendons and soft tissues as well as hardware-related problems, we designed an intramedullary fixation with bioabsorbable rods for the treatment of the metacarpal shaft fractures. Methods： Five patients with nine shaft fractures of the fourth and fifth metacarpi were treated with intramedullary absorbable implants and followed up with an average of 4.2 months postoperatively. Results： At final follow-up, all patients achieved fracture union with no signs of inflammatory or subcutaneous effusion. There was no shortening, angulatory, or rotatory deformity. There was almost full active extension range of motion （ROM） of the metacarpophalangeal joints while the active flexion ROM of these joints was 80.7 ± 9.6°. hand was 94.0 ± 9.6%. X-rays showed that the arch of the second Compared with the contralateral hand, the grip strength of the injured to fifth metacarpal heads was smooth. There were no intramedullary lytic changes and soft tissue swellings. Conclusion： The intramedullary absorbable implants are a safe, simple, and practical treatment for fourth and filth metacarpal fractures with good early clinical outcomes and no significant complications.

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.

Treatment of mallet fractures with a transverse two-hole mini plate

To the Editor:Mallet fracture is a very common hand injury.Although non-surgical treatment for some small fragment cases without distal interphalangeal joint(DIPJ)subluxation is acceptable,many authors have considered restoring the joint surface with accurate reduction to be important to prevent secondary osteoarthritis,loss of movement,and poor cosmetic outcomes.[1]To obtain an accurate reduction,several reduction and fixation techniques(such as extension block pinning,hook plate fixation,umbrella handle like K-wire fixation,and so on)have been developed.[2-4] But when the fracture fragment is small or comminuted,stable fixation is quite difficult to achieve based on the current techniques.To develop a more universal method to deal with different types of mallet fractures with fewer complications,a transverse two-hole mini plate was used.