Tsuyoshi Murase

Three-dimensional corrective osteotomy of malunited fractures of the upper extremity with use of a computer simulation system.

BACKGROUND Three-dimensional anatomical correction is desirable for the treatment of a long-bone deformity of the upper extremity. We developed an original system, including a three-dimensional computer simulation program and a custom-made surgical device designed on the basis of simulation, to achieve accurate results. In this study, we investigated the clinical application of this system using a corrective osteotomy of malunited fractures of the upper extremity. METHODS Twenty-two patients with a long-bone deformity of the upper extremity (four with a cubitus varus deformity, ten with a malunited forearm fracture, and eight with a malunited distal radial fracture) participated in this study. Three-dimensional computer models of the affected and contralateral, normal bones were constructed with use of data from computed tomography, and a deformity correction was simulated. A custom-made osteotomy template was designed and manufactured to reproduce the preoperative simulation during the actual surgery. When we performed the surgery, we placed the template on the bone surface, cut the bone through a slit on the template, and corrected the deformity as preoperatively simulated; this was followed by internal fixation. All patients underwent radiographic and clinical evaluations before surgery and at the time of the most recent follow-up. RESULTS A corrective osteotomy was achieved as simulated in all patients. Osseous union occurred in all patients within six months. Regarding cubitus varus deformity, the humerus-elbow-wrist angle and the anterior tilt of the distal part of the humerus were an average of 2 degrees and 28 degrees, respectively, after surgery. Radiographically, the preoperative angular deformities were nearly nonexistent after surgery. All radiographic parameters for malunited distal radial fractures were normalized. The range of forearm rotation in patients with forearm malunion and the range of wrist flexion-extension in patients with a malunited distal radial fracture improved after surgery. CONCLUSIONS Corrective osteotomy for a malunited fracture of the upper extremity with use of computer simulation and a custom-designed osteotomy template can accurately correct the deformity and improve the clinical outcome.

Interconnected porous hydroxyapatite ceramics for bone tissue engineering

Several porous calcium hydroxyapatite (HA) ceramics have been used clinically as bone substitutes, but most of them possessed few interpore connections, resulting in pathological fracture probably due to poor bone formation within the substitute. We recently developed a fully interconnected porous HA ceramic (IP-CHA) by adopting the ‘foam-gel’ technique. The IP-CHA had a three-dimensional structure with spherical pores of uniform size (average 150 μm, porosity 75%), which were interconnected by window-like holes (average diameter 40 μm), and also demonstrated adequate compression strength (10–12 MPa). In animal experiments, the IP-CHA showed superior osteoconduction, with the majority of pores filled with newly formed bone. The interconnected porous structure facilitates bone tissue engineering by allowing the introduction of mesenchymal cells, osteotropic agents such as bone morphogenetic protein or vasculature into the pores. Clinically, we have applied the IP-CHA to treat various bony defects in orthopaedic surgery, and radiographic examinations demonstrated that grafted IP-CHA gained radiopacity more quickly than the synthetic HA in clinical use previously. We review the accumulated data on bone tissue engineering using the novel scaffold and on clinical application in the orthopaedic field.

Interosseous membrane of the forearm: an anatomical study of ligament attachment locations.

PURPOSE The interosseous membrane (IOM) of the forearm is a stout ligamentous complex that reportedly comprises several ligamentous components. The purpose of this cadaveric study was to define all IOM ligaments and to clarify the precise attachment locations. METHODS Thirty forearms from 15 embalmed cadavers were used. After dissection, all IOM ligaments were identified, and attachments were measured from the tip of the radial styloid or the ulnar head. Attachment locations were represented as a percentage of total bone length from the distal end of the radius or ulna. RESULTS The IOM included 5 kinds of ligaments: central band, accessory band, distal oblique bundle, proximal oblique cord, and dorsal oblique accessory cord. The most distal and proximal ends of the radial origin of the central band were 53% and 64% of total radial length from the tip of the radial styloid, whereas those of the ulnar insertion were 29% and 44% of total ulnar length from the ulnar head. The center point of the radial origin and ulnar insertion of the accessory band were 37% and 23%, respectively. The center points of the ulnar origins and radial insertions were 15% and 10% for the distal oblique bundle; 80% and 79% for the proximal oblique cord; and 64% and 62% for the dorsal oblique accessory cord, respectively. CONCLUSIONS The present study clarified precise attachment locations of all representative IOM ligaments. This information will be useful in planning proper graft placement in ligament reconstruction surgery and for future biomechanics research into the function of the IOM ligaments.

Accuracy analysis of three-dimensional bone surface models of the forearm constructed from multidetector computed tomography data

We developed an original computer program that simulates upper limb reconstruction surgery using three‐dimensional (3D) bone models constructed from computed tomography (CT) data. However, the accuracy of a bone model has not been clarified, and radiation exposure from CT scanning posed a concern. The purpose of this study was to investigate the appropriate CT parameters required to reduce radiation exposure while maintaining the accuracy of 3D models of the forearm bones.

Methylcobalamin increases Erk1/2 and Akt activities through the methylation cycle and promotes nerve regeneration in a rat sciatic nerve injury model

Methylcobalamin is a vitamin B12 analog and is necessary for the maintenance of the nervous system. Although some previous studies have referred to the effects of methylcobalamin on neurons, the precise mechanism of this effect remains obscure. Here we show that methylcobalamin at concentrations above 100 nM promotes neurite outgrowth and neuronal survival and that these effects are mediated by the methylation cycle, a metabolic pathway involving methylation reactions. We also demonstrate that methylcobalamin increases Erk1/2 and Akt activities through the methylation cycle. In a rat sciatic nerve injury model, continuous administration of high doses of methylcobalamin improves nerve regeneration and functional recovery. Therefore, methylcobalamin may provide the basis for better treatments of nervous disorders through effective systemic or local delivery of high doses of methylcobalamin to target organs.

Interleukin-1 beta promotes sensory nerve regeneration after sciatic nerve injury.

Nerve injury brings about axonal disconnection, and thus axonal extension is one of the important steps for nerve regeneration. Expression of the pro-inflammatory cytokine interleukin-1 beta (IL-1beta) is increased at the early stage of nervous system injury, and previously IL-1beta has been reported to promote neurite outgrowth by inhibiting RhoA activity in vitro. However, the effect of IL-1beta on axonal extension in vivo has not been obvious. Now we examine whether IL-1beta takes advantages on sciatic nerve regeneration. Sciatic nerves of rats are transected and sutured, and IL-1beta or PBS is locally administered for 2 weeks. Although IL-1beta does not influence on motor functional recovery, it promotes sensory functional recovery, estimated by toe pinch test, and increases the number and the area of neurofilament-positive axons at 12 weeks compared with PBS. Moreover IL-1beta, which promotes Schwann cell proliferation and thus may inhibit myelination, does not impair remyelination, estimated by myelin basic protein. These findings suggest that IL-1beta may contribute to sensory nerve regeneration following sciatic nerve injury by promoting axonal extension.

Computer-Assisted Corrective Osteotomy for Malunited Diaphyseal Forearm Fractures

BACKGROUND Corrective osteotomy for malunited diaphyseal forearm fractures remains a challenging procedure. We developed a computer-assisted system for corrective surgery, including a three-dimensional simulation program and a custom-made osteotomy template, and investigated the results of corrective surgery for malunited diaphyseal forearm fractures with use of this technology. METHODS Twenty patients (fifteen male patients and five female patients) with malunited diaphyseal forearm fractures were managed with three-dimensional corrective osteotomy with a custom-made osteotomy template based on computer simulation. We performed osteotomy of both radius and ulna in fourteen patients and osteotomy of the radius alone in six patients. The median age at the time of surgery was eighteen years (range, eleven to forty-three years). The median duration between the time of injury and the time of surgery was thirty-three months (range, five to 384 months). The minimum duration of follow-up was twenty-four months (median, twenty-nine months; range, twenty-four to forty-eight months). To evaluate the results, we compared preoperative and postoperative data from radiographs, forearm motion, grip strength, and pain. RESULTS The average radiographic deformity angle preoperatively was 21° (range, 12° to 35°) compared with the normal arm; the radiographic deformity angle was improved to 1° (range, 0° to 4°) postoperatively. The distal radioulnar joints of both sides were symmetric on postoperative radiographs regarding the relative lengths of the radius and ulna. In eighteen patients who had a restricted range of forearm motion preoperatively, the mean arc of forearm motion improved from 76° (range, 25° to 160°) preoperatively to 152° (range, 80° to 180°) postoperatively (p < 0.01). However, forearm supination was still restricted by ≥ 70° in three patients who had been younger than ten years old at the time of the initial injury and who had long-standing malunion for ninety-six months or longer. Painful recurrent dislocation of the distal ulna or radial head resolved or decreased in five patients. Average grip strength improved from 82% to 94% compared with that of the contralateral, normal side. CONCLUSIONS Computer-assisted osteotomy can provide excellent radiographic and clinical outcome for the treatment of malunited diaphyseal forearm fractures. Satisfactory restoration of forearm motion can be achieved even in relatively long-standing cases in adults.

Corrective Osteotomy for Malunited Intra-Articular Fracture of the Distal Radius Using a Custom-Made Surgical Guide Based on Three-Dimensional Computer Simulation: Case Report

We report a case of malunited intra-articular fracture of the distal radius successfully treated with corrective osteotomy through an extra-articular approach using a custom-made surgical guide that was designed based on preoperative three-dimensional computer simulation.

The in vivo isometric point of the lateral ligament of the elbow.

BACKGROUND Many reports have discussed reconstruction of the lateral ulnar collateral ligament for the treatment of posterolateral rotatory instability of the elbow, but information regarding the isometric point of the lateral ligament of the elbow is limited. The purposes of the present study were to investigate the in vivo and three-dimensional length changes of the lateral ulnar collateral ligament and the radial collateral ligament during elbow flexion in order to clarify the role of these ligaments as well as to identify the isometric point for the reconstructed lateral ulnar collateral ligament on the humerus where the grafted tendon should be anchored. METHODS We studied in vivo and three-dimensional kinematics of the normal elbow joint with use of a markerless bone-registration technique. Magnetic resonance images of the right elbows of seven healthy volunteers were acquired in six positions between 0 degrees and 135 degrees of flexion. We created three-dimensional models of the elbow bones, the lateral ulnar collateral ligament, and the radial collateral ligament. The ligament models were based on the shortest calculated paths between each origin and insertion in three-dimensional space with the bone as obstacles. We calculated two types of three-dimensional distances for the ligament paths with each flexion position: (1) between the center of the capitellum and the distal insertions of the ligaments (to investigate the physiological change in ligament length) and (2) between eight different humeral origins and the one typical insertion of the lateral ulnar collateral ligament (to identify the isometric point of the reconstructed lateral ulnar collateral ligament). RESULTS The three-dimensional distance for the lateral ulnar collateral ligament was found to increase during elbow flexion, whereas that for the radial collateral ligament changed little. The path of the lateral ulnar collateral ligament gradually developed a detour because of the osseous protrusion of the lateral condyle with flexion. The most isometric point for the reconstructed lateral ulnar collateral ligament was calculated to be at a point 2 mm proximal to the center of the capitellum. CONCLUSIONS The radial collateral ligament is essentially isometric, but the lateral ulnar collateral ligament is not. The lateral ulnar collateral ligament is loose in elbow extension and becomes tight with elbow flexion.

Change in the Length of the Ulnocarpal Ligaments During Radiocarpal Motion: Possible Impact on Triangular Fibrocartilage Complex Foveal Tears

PURPOSE The fovea of the ulnar head is the primary attachment site for both the distal radioulnar and the ulnocarpal ligaments. Thus, both ligaments should be simultaneously affected by the traumatic avulsion of the triangular fibrocartilage complex from its ulnar attachment. Little attention, however, has been directed toward the role of the ulnocarpal ligaments in the mechanics of this type of injury. The purpose of this study was to investigate the changes in length of the ulnocarpal ligaments during various radiocarpal motions and to determine the type of radiocarpal motion that makes the ulnocarpal ligament taut and that could cause foveal avulsion if it were excessive. METHODS The 3-dimensional kinematics of the wrist joint were investigated noninvasively using a markerless bone registration technique in vivo. Magnetic resonance images of the wrists of 15 healthy volunteers were acquired in at least 5 positions during each wrist flexion-extension motion, radioulnar deviation, or the so called dart-throwing motion (radial extension-ulnar flexion motion). The 3-dimensional ligament paths of the ulnotriquetral, ulnolunate, ulnocapitate, and palmar radioulnar ligaments were modeled as the shortest paths between the fovea and the insertion point of each ligament. Changes in the 3-dimensional ligament length of each ligament between the neutral position and each wrist position were then calculated. RESULTS The lengths of the ulnotriquetral and ulnocapitate ligaments increased the most on wrist radial extension, and the length of the ulnolunate ligament increased the most on wrist extension. The length of the palmar radioulnar ligament changed minimally during any motion. CONCLUSIONS The ulnocarpal ligaments are likely to be stretched tensely in wrist radial extension and wrist extension. This study supports the hypothesis that one of the mechanisms responsible for a triangular fibrocartilage complex foveal tear is excessive traction of the ulnocarpal ligament caused by a fall on the outstretched hand.