Biomedical subjects
Publications and source records attributed to E Nakao.
We report a case of a locked thumb metacarpophalangeal joint secondary to metacarpal head fracture. As fractures of the radial condyle are not readily seen in routine X-rays, other imaging modalities, including CT, should be considered if the patient complains of limited extension after hyperextension injury of the thumb.
Ulnocarpal impaction syndrome was diagnosed in six wrists of five patients with neutral or negative ulnar variance. All underwent ulnar shortening with satisfactory results. The average grip strength increased from 53% to 78% and the range of flexion-extension increased from 82% to 93%, the mean Cooney's score improved from 25 to 83. These cases show that ulnocarpal impaction syndrome can occur in wrists with zero or negative ulnar variance, and that ulnar shortening is an effective treatment for such wrists.
We conducted a retrospective review of 11 patients with bilateral Kienbock's disease from our series of 251 patients with Kienbock's disease. There were no significant differences in radiographic parameters, including ulnar variance and carpal bone angle, between those with unilateral and those with bilateral Kienbock's disease. None of the patients with bilateral disease had been treated with corticosteroids or had a systemic disease that predisposed to osteonecrosis. Thus, this study failed to demonstrate any risk factor for bilateral, as opposed to unilateral Kienbock's disease.
Posteroanterior radiographs of 102 normal wrists were studied to determine the morphological characteristics of the ulnar head associated with the value of ulnar variance. Ulnar variance, ulnar styloid length, ulnar head diameter, ulnar seat inclination, and the distance of ulnar head peak to the distal radioulnar joint were measured together with the third metacarpal length as a reference of the size of the wrist. Moderate correlation was confirmed not only between ulnar variance and ulnar seat inclination but also between ulnar variance and the distance of the ulnar head peak. Furthermore, we found a statistically significant correlation between ulnar variance and ulnar head diameter. The results showed that whole ulnar head configurations are affected by ulnar variance although there are considerable variations.
Scaphoid fracture patterns can be divided into volar and dorsal type using three-dimensional computed tomography. Ninety-nine patients underwent this examination plus radiography to determine how often fracture pattern was identifiable by radiography including proximal fragment ratio (PFR) measurement. Oblique radiographs obtained at 45 degrees of pronation demonstrated a volar displacement in 28 of 37 volar type fractures in three-dimensional computed tomography (76%), while as oblique view with 45 degrees of supination could identify the dorsal type in ten of 18 (56%). PFR showed a significant difference, with means of 0.59 for volar type and 0.43 for dorsal type. Using oblique views in the two rotational directions together with the PFR, the two fracture patterns could be differentiated in 35 of 43 fractures (81%). No differences were evident between the two fracture patterns with respect to prevalence of dorsal intercalated segment instability deformity.
BACKGROUND: The treatment of chronic radial head dislocation remains controversial. High rates of redislocation and complications have been reported after surgery. In our view, correction of malalignment with ulnar osteotomy is the key to a good surgical result. METHODS: Since 1975, twenty-two patients were treated surgically for chronic radial head dislocation at our hospital. The procedure consisted of open reduction of a dislocated radial head followed by radial and/or ulnar osteotomy, with or without reconstruction of the annular ligament or by reconstruction of the annular ligament alone. The ages of the patients ranged from four to twenty years. In 1991, we modified the surgical technique by performing an oblique ulnar osteotomy with angulation and elongation and rigid plate fixation. Bone-grafting at the osteotomy site was also performed if necessary. A cast was applied with the forearm in neutral rotation and was worn for two to four weeks. Nine patients were treated with this modified technique. RESULTS: The mean interval between the initial injury and the reconstructive surgery was ten months. There were no serious surgical complications. Of the thirteen patients treated before 1991, four had a good reduction and seven had redislocation. Seven patients had restricted forearm rotation postoperatively. Of the nine patients treated with the modified osteotomy since 1991, seven had a good reduction. Two patients, who had had slight radial head deformity preoperatively, had subluxation postoperatively. Two patients had restricted forearm rotation. CONCLUSIONS: Since we modified our technique for ulnar osteotomy, good reduction of the radial head has been achieved without causing serious contracture. Both angulation and elongation of the ulna are required to allow the radial head to reduce.
Thirty-five callus distractions of the forearm were carried out in 23 patients, who were divided into two groups according to the cause of the shortening. Eleven cases in group A had congenital dysplasia, and the 12 cases in group B had growth disturbances from tumours or infection. The mean amount of lengthening was 27 mm in group A and 25 mm in group B. The mean percentage increase in length was 35% and 17%, respectively. The mean duration of fixation was 159 days and 127 days, respectively. The Healing Index had a positive correlation with the age at surgery in group A, but not in group B. The main complication was callus deformity after the removal of a fixator, which was especially frequent in group A. To avoid complications, the aetiology of shortening and the age of the patient should be considered when deciding the surgical protocol.
We experienced 16 patients with a fracture of the hook of the hamate. The routine posteroanterior view raised the suspicion of fracture in four of 13 patients (31%), the carpal tunnel view showed the actual fractures in six of 14 patients (43%), and the supine oblique radiographic view of the wrist showed fractures in eight of ten patients (80%). Computed tomography corroborated the fracture in all eight patients (100%). Computerized tomography proved most useful for accurate diagnosis of fracture of the hook of the hamate.
Fifteen hands with congenital metacarpal fusions were treated operatively by osteotomy combined either with the use of a silicone block or a distraction device. The aim of the silicone block was to separate the fused metacarpals, but it was buried in the metacarpals at follow-up, with recurrence of fusion. By the distraction technique, 13 mm of lengthening was obtained. The average length of the little metacarpal was 88% of that of the long finger metacarpal. Both methods were effective in correcting the abduction deformity of the little finger by a mean of 34 degrees, and increasing the range of motion of the metacarpophalangeal joint to 28 degrees of active flexion. Although the distraction method took longer than the silicone block method, the final appearance of the hand was better.
The outcomes in 20 patients with advanced Kienböck's disease treated by proximal row carpectomy (seven patients) or limited wrist arthrodesis (13 patients) were reviewed retrospectively. Postoperatively, the results were more satisfactory in terms of wrist pain, the range of wrist flexion-extension, and grip strength following limited wrist arthrodesis than after proximal row carpectomy, although the differences were not statistically significant. We recommend scaphotrapeziotrapezoid arthrodesis in selected patients with advanced Kienböck's disease who have a fragmented lunate.
Four patients with dorsal dislocation of the distal radioulnar joint and ulnar styloid malunion had corrective osteotomy of the ulnar styloid. Dislocation of the distal radioulnar joint was reduced in three of four patients. Subluxation persisted in the remaining patient. Wrist function improved in all patients. These results support the contention that a displaced ulnar styloid fracture with distal radioulnar joint dislocation should be reduced and internally fixed. Corrective osteotomy is recommended for malunion of the ulnar styloid associated with dislocation of the distal radioulnar joint.
The purpose of this experiment was to determine the amount of tissue that must be sectioned to adequately decompress the median nerve during an endoscopic carpal tunnel release procedure. In 6 fresh cadaver forearms, 2 balloons were inserted into the carpal tunnel. The first balloon was filled with saline solution to cause an initial carpal intracanal pressure of 50 mmHg. Pressure measurements were recorded, using the second balloon, at various increments of the flexor retinaculum division at 3 wrist positions (neutral, 35 degrees ; flexion, 35 degrees extension). At all increments of sectioning, carpal tunnel pressures in the neutral wrist position were consistently lowest and the values in 35 degrees extension were greatest. At each wrist flexion/extension angle, the pressure statistically decreased during incremental division of the flexor retinaculum. Incomplete release of the transverse carpal ligament resulted in incomplete decompression in the canal. Sectioning the overlying aponeurosis caused a further significant decrease in intracanal pressure.
Forty-five patients with persistent ulnar-sided wrist pain and a positive ulnocarpal stress test were investigated by X-ray, arthrography, 99mTechnetium bone scanning, magnetic resonance imaging and wrist arthroscopy. Ulnar wrist pathology was positively identified in nine of 45 patients by X-ray, 18 of 37 by arthrography, 19 of 27 by bone scan, four of 33 by MRI, and in all 45 patients by arthroscopy. The final diagnosis was ulnocarpal abutment syndrome in 28 patients, traumatic triangular fibrocartilage (TFC) tear in six, lunotriquetral (LT) ligament tear in five, TFC and LT ligament tear in one, wrist arthritis in four and cartilaginous free body in one. The ulnocarpal stress test is a useful provocative test, and a positive test suggests the presence of ulnar-sided wrist pathology. The test is sufficiently sensitive to warrant further investigation by arthroscopy.
Many studies have suggested an association between blood pressure (BP) and both insulinaemia and haematocrit values in Western populations. However, relatively few data regarding such associations for the Japanese population are available. We investigated the relationship between BP and various parameters, including insulin and haematocrit, in 269 healthy Japanese individuals (113 men and 156 women) over 60 years of age. The data were analysed by stepwise multiple regression analysis. In men, the most important determinant of systolic BP (SBP) and diastolic BP (DBP) was the plasma insulin concentration (beta = 0.32, F = 12.4, P < 0.001 and beta = 0.32, F = 13, P < 0.001, respectively), and haematocrit was found to be associated with DBP (beta = 0.21, F = 5.3, P < 0.05). In women, fasting insulins were unrelated to BP, but fasting plasma glucose and triglyceride concentrations and age were associated with SBP (beta = 0.29, F = 15.5, P < 0.001, beta = 0.27, F = 14.3, P < 0.001, and beta = 0.2, F = 7.8, P < 0.01, respectively), and haematocrit, fasting plasma glucose concentration and age were associated with DBP (beta = 0.29, F = 14, P < 0.001, beta = 0.2, F = 6.9, P < 0.01 and beta = 0.2, F = 6.3, P < 0.05, respectively). These results suggest that the insulin-BP associations in healthy Japanese subjects over 60 years of age differ according to sex, and that haematocrit is an important determinant of DBP in both sexes in our population.
Bilateral wrist computed tomography (CT) was performed in 30 patients with suspected unilateral distal radioulnar joint (DRUJ) subluxation to evaluate dynamic DRUJ CT scanning with a straight elbow. Five CT criteria for diagnosing dorsovolar subluxation were examined. Maximum active supination and pronation on a conventional scanning table yielded satisfactory rotation (mean +/- SD, 119 degrees +/- 29 degrees) at the DRUJ, thus permitting a dynamic diagnosis of DRUJ subluxation. The radioulnar line method and the congruity method frequently yielded false positive results compared with bilateral diagnosis and were unreliable. Modifications of these two methods achieved sensitivity and specificity comparable to the epicenter method. We recommended the modified radioulnar line method for diagnosing dorsovolar subluxation using unilateral CT because of its excellent sensitivity and specificity combined with ease of technique.
A patient who had suffered from ulnar wrist pain for 3 years was diagnosed arthroscopically as having triquetrohamate impaction syndrome. Improvement of symptoms was obtained by arthroscopic treatment. This syndrome and the use of midcarpal arthroscopy are discussed.
The use of standard lateral roentgenography for diagnosing distal radioulnar joint (DRUJ) subluxation and dislocation was investigated. Using a wrist support, bilateral standard lateral roentgenograms of the wrist were obtained in 42 patients with normal wrists and in 56 patients with a unilateral wrist injury. In normal wrists the difference between the radioulnar distance in the right and the left wrist did not exceed 4 mm when the difference in the pisoscaphoid distance was less than 3 mm. Of the 36 patients with wrist injury whose difference in pisoscaphoid distance was less than 3 mm, 15 had a radioulnar distance of 5 mm or more, and computed tomography (CT) confirmed DRUJ dislocation in 14. Concordance between lateral roentgenograms and CT was present in 33 of 36 patients (92%). These results demonstrate the value of a standardized technique for bilateral lateral roentgenography in diagnosing DRUJ subluxation and dislocation.
The effect of hydrostatic pressure on the bindability and digestibility of raw corn starch with two types of glucoamylase [EC 3.2.1.3] from Rhizopus sp., Gluc1 and Gluc2, was investigated in the range of 100 to 600 MPa. Pressurization of raw starch at 100 to 300 MPa for 1 h had no detectable effect, whereas pressurization at higher pressures than 400 MPa markedly enhanced the bindability and digestibility with Gluc1 and Gluc2, especially with Gluc2, which scarcely binds to raw starch and has much lower activity than Gluc1 towards raw starch. The binding constants Ks of Gluc1 and Gluc2 for the 400-MPa-pressurized starch reached 16 and 1.6 x 10(5) M-1, respectively, as compared with the Ks of 2.1 and 0.082 x 10(5) M-1 for raw starch. The 500- to 600-MPa-pressurized starch was digested by Gluc1 and Gluc2 at about 4.2 and 80 times higher rates, respectively, than raw starch. Thus, the high-pressure-treated starch was hardly distinguishable from high temperature (75 to 100 degrees C)-treated starch at least with respect to behavior with the enzymes, although some difference was observed between these starches by scanning electron microscopy and differential scanning calorimetry.