Ryogo Nakamura

Radial wedge osteotomy for Kienböck disease.

A radial wedge osteotomy, with reduction of the inclination angle of the distal part of the radius, was performed in twenty-seven patients who had Kienböck disease. After two to five years of follow-up, all of the patients were free of pain or had only mild pain in the wrist with strenuous activity. Flexion-extension of the wrist improved by more than 10 degrees in about half of the patients, and in most of the patients the grip strength increased by five kilograms or more. All but two of the postoperative results were satisfactory, as evaluated by the criteria of Lichtman et al. The osteotomy was effective even in patients who had zero or positive ulnar variance.

Analysis of scaphoid fracture displacement by three-dimensional computed tomography

Scaphoid fracture displacement was studied in twenty-five patients using three-dimensional computed tomography. Fracture displacement was more readily detected and distinct in three-dimensional computed tomography images than in plain radiography. Two different types of offset of the distal fragment with respect to the proximal fragment are described on three dimensional computed tomography; volar type and dorsal type. In the volar type, the distal fragment overhung in the volar direction relative to the proximal fragment and was frequently accompanied by humpback deformity and axial rotation. In the dorsal type, the distal fragment slipped dorsal on the proximal fragment and was commonly accompanied by humpback deformity. The volar type had a transverse or vertical fracture line on both the volar and dorsal surfaces of the scaphoid, while the dorsal type had a horizontal fracture line. The volar type was frequently found when the fracture was distal, whereas the dorsal type was noted more frequently for proximally located fracture.

Biomechanical analysis of radial wedge osteotomy for the treatment of Kienböck's disease

Biomechanical analysis of force transmission through the lunate was performed with the use of a two-dimensional mathematical model to evaluate the usefulness of radial wedge osteotomy, a procedure that decreases radial inclination, in the treatment of Kienböcks disease. The forces acting on the carpal bones were compared before and after radial wedge osteotomy in 29 patients with Kienböcks disease. The average osteotomy angle was 9.6 degrees. The total force through the lunocapitate joint at the midcarpal level was decreased by 23%, while the total force through the radiolunate and ulnolunate joints at the radioulnocarpal level was decreased by 10% and 36%, respectively. These changes correlated directly with the osteotomy angle and demonstrate decompression of the lunate by radial wedge osteotomy.

Surgical outcome of radial osteotomy for Kienböck's disease : minimum 10 years of follow-up

PURPOSE Long-term results of radial osteotomy for Kienböcks disease seldom are seen in the literature. The purpose of this study was to report the minimum 10-year results and to compare them with the 5-year results to determine whether the favorable intermediate-term results were maintained. METHODS Twenty-five patients who underwent radial osteotomy were followed-up for a mean period of 14.5 years. They were examined for pain, grip strength, and wrist range of motion (ROM). Through a review of clinical records, 5-year postoperative results were collected. The carpal height ratio and Ståhls index were measured and the x-rays were inspected for osteoarthritic changes. We devised an original lunate grade to evaluate radiologic improvement of the ischemic lunate. Overall results were evaluated using Cooneys wrist function score and Nakamuras scoring system for Kienböcks disease. The long-term results were compared with both the preoperative status and the 5-year results. RESULTS Pain, ROM, and grip strength were improved significantly after surgery, and the results were maintained for a long period. Carpal height ratio and Ståhls index did not show significant improvements but ischemic lunate showed certain radiologic improvements with time by the lunate grade system. Osteoarthritic changes were observed in 54% of patients at 5 years and in 73% of patients at the final follow-up evaluation, but the arthrosis generally was mild and did not affect the clinical results. Cooneys wrist function score was excellent or good in 96% of the patients, and the results with Nakamuras scoring system for Kienböcks disease were excellent or good in 68% of the patients at the final follow-up evaluation. The percentages were the same 5 years after surgery. CONCLUSIONS Radial osteotomy for Kienböcks disease is a reasonable treatment option and clinical improvement lasts for a long period of time. Although radiologic improvement was not drastic, the inner structure such as sclerotic change or bone cysts of the lunate improved with time, indicating healing of the ischemic lunate. Severe osteoarthritic change or proximal migration of the capitate can be avoided.

Radial osteotomy for Kienböck's disease evaluated by magnetic resonance imaging: 24 cases followed for 1–3 years

24 patients with Kienböcks disease were followed with magnetic resonance imaging (MRI) for 1-3 years. 9 patients were treated with radial shortening, 10 with radial wedge osteotomy and 5 patients were treated non-operatively. Signal intensity of the lunate on T1-weighted or T2-weighted images increased postoperatively in all operated on patients, and normal or near-normal signal intensity was observed in 9 patients on T1-weighted images and in 15 patients on T2-weighted images postoperatively. Signal intensity did not increase in any patient treated non-operatively. The postoperative increase in signal intensity on MRI following radial shortening and radial wedge osteotomy presumably is due to revascularization of the lunate.

Reduction of the scaphoid fracture with DISI alignment

Eight cases of symptomatic malunion and nonunion of scaphoid fractures with dorsiflexed intercalated segment instability (DISI) alignment were treated by open reduction, anterior wedge-shaped bone grafting, and internal fixation using Herberts screw. In four malunited fractures, osteotomy at the fracture line was done before the reduction. The DISI alignment was reduced by insertion of the Kirschner wire into the lunate and flexing it anteriorly. After the bone grafting to the anterior bony defect of the scaphoid, which was created by the Kirschner wire reduction, internal fixation was accomplished by the use of Herberts screw. In all cases fusion was obtained within 4 months. Radiographic assessment indicated that the DISI alignment and the angulated scaphoid were corrected to achieve a nearly normal pattern. Pain, restricted motion of the wrist, and the grip strength were improved.

Nonoperative treatment of camptodactyly

Twenty-four patients with camptodactyly of their small fingers were treated with a dynamic splint. Most of the patients could extend the proximal interphalangeal (PIP) joints within a few months by using the dynamic splint 24 hours a day. After almost full extension of the proximal interphalangeal joint was achieved, splinting for 8 hours a day produced good final results. However, after the splint was removed, contracture tended to recur. Although further studies are needed to determine the optimum termination of treatment, in our opinion it should be when the growth plate is closed, and longitudinal growth of the finger no longer occurs.

Retrograde tracing and electrophysiological findings of collateral sprouting after end-to-side neurorrhaphy.

The aim of this study was to seek more potent evidences of collateral sprouting for both motor and sensory nerve fibres after end-to-side neurorrhaphy using a modified double-labelling retrograde tracing method and to investigate the function of regenerated motor axons with electrophysiological evaluation. Four groups (n=4 for each group) were used: end-to-end coaptation (six months postoperatively), end-to-side coaptation (four months and six months postoperatively) and normal control. Two fluorescent tracers (true blue and diamidino yellow) were applied to the proximal ends of tibial and common peroneal nerves, respectively after four or six months of nerve coaptation. Five days later, we only found single-labelled motor and sensory neurons in the normal and end-to-end coaptation groups, while some dual-labelled neurons can be identified in end-to-side coaptation groups. Four months after surgery, the motor nerve conduction velocity in end-to-side coaptation was significantly slower than in the normal control. But no difference was found in the sixth month. These results suggest that end-to-side neurorrhaphy can induce the functional collateral sprouting of both motor and sensory axons in the peripheral nerve.

Sports-related Kienböck's disease

Ten patients with Kienbocks disease who were actively engaged in sports activities involving repeated minimal trauma to the wrist are presented. Comparative studies between the 10 patients with sports-related Kienböcks disease and 82 manual laborers with Kienböcks dis ease showed no difference in clinical presentation or radiographic findings. The history of repeated minimal trauma appeared to be similar in the two groups. There fore, sports activities in which the wrist suffers repeated impact can lead to the development of Kienböcks disease identical to that occurring in manual laborers, although the sports group was younger and had smaller ulnar variance. Radial osteotomy improved clinical symptoms even in sports-related Kienböcks disease.

Arthroscopic assessment of Kienböck's disease

Arthroscopic examination was performed on 32 wrists of 32 patients with Kienböcks disease to relate the appearance of the intraarticular structures, particularly the articular cartilage, to the radiographic stage. The articular cartilage showed osteoarthritic changes in stage III, although this was not evident on plain radiographs. Cracking in the distal facet and flapping at the proximal facet of the lunate were identified as features of Kienböcks disease. The incidence of interosseous ligament tears was correlated with radiographically determined stage, whereas changes in triangular fibrocartilage were correlated with age and ulnar variance. Wrist arthroscopy is a useful staging tool for Kienböcks disease, supplying helpful information about the intraarticular pathoanatomy which can be used to guide patient management.