Shigeharu Uchiyama

Normal kinematics of carpal bones: A three-dimensional analysis of carpal bone motion relative to the radius

Normal carpal kinematics were studied in 22 cadaver specimens using a biplanar radiography method. The kinematics of the trapezium, capitate, hamate, scaphoid, lunate, and triquetrum were determined during wrist motion in sagittal and coronal planes. The results were expressed using the concept of the screw displacement axis and converted to describe the magnitude of rotation about and translation along three axes (X-axis: pronation-supination axis, Y-axis: flexion-extension axis, and Z-axis: radial-ulnar deviation axis) commonly used for the wrist. The orientation of these axes is expressed relative to the radius. Within the proximal carpal row, considerable differences of carpal behavior around the Y-axis were observed during sagittal plane motion of the wrist. The scaphoid exhibited the greatest magnitude of rotation, and the lunate the least. The magnitude of rotation of the carpal bones around the X-axis during sagittal plane motion of the wrist was small. The proximal carpal bones exhibited some ulnar deviation in 60 degrees of wrist flexion. During coronal plane motion of the wrist, the magnitude of radial-ulnar deviation of the distal carpal bones was mutually similar and generally of a greater magnitude than that of the proximal carpal bones. The proximal carpal bones experienced some flexion during radial deviation of the wrist and extension during ulnar deviation of the wrist. Translation was generally minimal in all carpal bones throughout wrist motion. This study reports results from the largest cadaver wrist kinematics study completed to date. The accuracy of the current method was improved when compared to previous studies. A sufficient number of specimens to allow statistical comparison was used and minimal interspecimen variability was noted. This study enabled a precise description of quantitative analyses of normal carpal kinematics relative to the radius.

Current concepts of carpal tunnel syndrome: pathophysiology, treatment, and evaluation.

The current concepts of carpal tunnel syndrome (CTS) with respect to its pathophysiology, treatment, and evaluation are discussed. With regard to the pathophysiology of idiopathic CTS, biomechanical studies to determine the kinematics of the flexor tendon, and the median nerve inside the carpal tunnel may provide valuable insights. Different degrees of excursion between the flexor tendons and the median nerve could cause strain and microdamage to the synovial tissue; this has been microscopically observed. A biomechanical approach for elucidating the events that trigger the development of CTS seems interesting; however, there are limitations to its applications. Endoscopic carpal tunnel release (ECTR) is a useful technique for achieving median nerve decompression. However, it is not considered superior to conventional open carpal tunnel release in terms of fast recovery of hand function. Unless the effect of inserting a cannula into the diseased carpal tunnel on the median nerve function is quantitatively elucidated, ECTR will not be regarded as a standard procedure for relieving the median nerve from chronic compression. The treatment of CTS should be evaluated on the basis of patient-oriented questionnaires as well as conventional instruments because these questionnaires have been validated and found to be highly responsive to the treatment. It should be noted that nerve conduction studies exclusively evaluate the function of the median nerve, whereas patient-oriented questionnaires take into account not only the symptoms of CTS but other accompanying pathologies as well, such as flexor tenosynovitis. In Japan, the number of CTS patients is expected to rise; this may be attributed to a general increase in the life-span of the Japanese and increase in the number of diabetic patients. Thus, more efforts should be directed toward elucidating the pathophysiology of so-called idiopathic CTS, so that new treatment strategies can be established for CTS of different pathologies.

Gliding resistance of extrasynovial and intrasynovial tendons through the A2 pulley.

The gliding ability of the flexor digitorum profundus tendon and of the palmaris longus tendon through the A2 pulley was compared, in terms of gliding resistance, with use of a system that we developed. Fourteen digits and the ipsilateral palmaris longus tendons from fourteen cadavera were used. The average gliding resistance at the interface between the palmaris longus tendon and the A2 pulley was found to be greater than that between the flexor digitorum profundus tendon and the A2 pulley under similar loading conditions. We concluded that the gliding ability of the palmaris longus tendon was inferior to that of the flexor digitorum profundus tendon in vitro. CLINICAL RELEVANCE: The findings of the present study are consistent with those of in vivo experiments in which extrasynovial tendon grafts have been associated with substantial formation of adhesions. The adhesions may be explained by the poor gliding ability of the palmaris longus tendon. The palmaris longus tendon may have limitations, because of gliding resistance, when it is used as a graft to reconstruct flexor tendons in the digits.

Flexor tendon-pulley interaction after tendon repair: A biomechanical study

Ten normal ring fingers from ten donors were used to determine the effect of flexor tendon repair on the gliding resistance between the tendon and the A2 pulley. Gliding resistance was measured for the intact FDP tendon and for the same tendon after it was cut transversely and repaired with a 4/0 Ticron core suture and a 6/0 running epitendinous nylon suture. After repair, the gliding pattern of the tendon through the A2 pulley changed significantly. The resistance and the friction coefficient were approximately doubled (P < 0.005).Ten normal ring fingers from ten donors were used to determine the effect of flexor tendon repair on the gliding resistance between the tendon and the A2 pulley. Gliding resistance was measured for the intact FDP tendon and for the same tendon after it was cut transversely and repaired with a 4/0 Ticron core suture and a 6/0 running epitendinous nylon suture. After repair, the gliding pattern of the tendon through the A2 pulley changed significantly. The resistance and the friction coefficient were approximately doubled (P<0.005).

Boundary lubrication between the tendon and the pulley in the finger

The lubrication mechanism between the human flexor digitorum profundus tendon and the A2 pulley was investigated in vitro. The gliding resistance at the interface between the tendon and the pulley increased significantly after the tendon had been treated with a hyaluronidase solution. Alcian-blue staining of the surface of the tendon before and after it was treated with hyaluronidase suggested the presence of hyaluronate complex. Alcian blue-positive and hyaluronidase-sensitive materials, such as hyaluronate or proteoglycan, in the synovial membrane and the matrix of the tendon, may act as a boundary lubricant, facilitating the gliding and reducing the resistance between the tendon and the pulley. CLINICAL RELEVANCE: The use of intrasynovial tendon donor grafts, which appear to possess a boundary lubricant on their surface, may result in improved gliding of the tendon postoperatively, compared with more traditional grafts, such as the palmaris longus tendon, taken from extrasynovial sources.

Quantitative MRI of the wrist and nerve conduction studies in patients with idiopathic carpal tunnel syndrome

Objective: To correlate morphological findings of idiopathic carpal tunnel syndrome (CTS) with the function of the median nerve. Methods: In this study, 105 wrists of 105 women patients with idiopathic CTS, and 36 wrists of 36 female volunteers were subjected to nerve conduction studies and MRI. Cross sectional area, signal intensity ratio, and the flattening ratio of the median nerve, carpal tunnel area, flexor tendon area, synovial area, and intersynovial space, and the palmar bowing of the transverse carpal ligament (TCL) were quantified by MRI and correlated with the severity of the disease determined by nerve conduction studies. Results: Cross sectional areas of the median nerve, flexor tendons, and carpal tunnel, and the palmar bowing of the TCL of the CTS groups were greater than in the control group, but differences were not detected among the CTS groups for the area of the flexor tendons and the carpal tunnel. Enlargement, flattening, and high signal intensity of the median nerve at the distal radioulnar joint level were more significant in the advanced than in the earlier stages of the disease. Increase in palmar bowing of the TCL was less prominent in the most advanced group. Linear correlation between the area of the carpal tunnel and palmar bowing of the TCL was noted. Conclusion: Severity of the disease could be judged by evaluating not only longitudinal changes of signal intensity and configuration of the median nerve, but also palmar bowing of the TCL. Increased palmar bowing of the TCL was found to be associated with an increase in the area of the carpal tunnel.

Long-term clinical and radiographic outcomes after open reduction for missed Monteggia fracture-dislocations in children.

BACKGROUND There have been few reports on the long-term outcomes after the operative treatment of missed Monteggia fracture-dislocations in children. The purpose of the present study was to evaluate the long-term clinical and radiographic outcomes after open reduction for the treatment of a missed Monteggia fracture-dislocation. METHODS We postoperatively investigated the clinical and radiographic outcomes for twenty-two children with a missed Monteggia fracture. The study group included fourteen boys and eight girls who had had a mean age of ten years (range, four years to fifteen years and eleven months) at the time of open reduction. Each patient had been managed with open reduction of the radial head combined with a posterior bending elongation ulnar osteotomy and anular ligament reconstruction. Clinical and radiographic outcomes were reviewed over a mean duration of follow-up of seven years. RESULTS The postoperative Mayo Elbow Performance Index at the time of follow-up ranged from 65 to 100, with nineteen excellent, two good, one fair, and no poor results. The radial head remained in a completely reduced position in seventeen patients and was subluxated in five patients at the time of the latest follow-up. In four patients, osteoarthritic changes were observed at the radiohumeral joint. Radiographically, there were fifteen good, seven fair, and no poor results. A good radiographic result was obtained in all of the patients who had undergone open reduction within three years after the injury or before the age of twelve years, whereas a fair result was obtained in seven of the remaining eight patients. CONCLUSIONS If open reduction for the treatment of a missed Monteggia fracture is performed when the patient is less than twelve years of age or within three years after the injury, good long-term clinical and radiographic outcomes can be expected.

Microendoscopic discectomy (MED) for lumbar disc prolapse

Microendoscopic discectomy (MED), which combines traditional lumbar microsurgical techniques with endoscopy, is being used as a minimally invasive procedure for lumbar disc herniation. We reviewed 30 patients who underwent MED at our institution and compared their outcome with that of patients subjected to the conventional method. Laboratory data suggested that MED was less invasive surgery. Moreover, MED allowed an early return to work. However, the difficulties of this endoscopic procedure were evident, because of the limited exposure and two-dimensional video display. The potential injury of the nerve root and prolonged surgical time remain as matters of serious concern. To overcome this problem, we used an operative magnifying glass during surgery and this helped us to accomplish the procedure comfortably. We recommend the use of an operative magnifying glass in the early stage of the introduction of MED, for it is quite useful to identify the three-dimensional relationships of the structures.

Validation of the Japanese Society for Surgery of the Hand Version of the Quick Disability of the Arm, Shoulder, and Hand (QuickDASH-JSSH) questionnaire

BackgroundThe Quick Disability of the Arm, Shoulder, and Hand (QuickDASH) questionnaire is a region-specific, self-administered questionnaire, which consists of a disability/symptom (QuickDASH-DS) scale, and the same two optional modules, the work (DASH-W) and the sport/music (DASH-SM) modules, as the DASH. After the Japanese version of DASH (DASH-JSSH) was cross-culturally adapted and developed, we made the Japanese version of QuickDASH (QuickDASH-JSSH) by extracting 11 out of 30 items of the DASH-JSSH regarding disability/symptoms. The purpose of this study was to test the reliability, validity, and responsiveness of QuickDASH-JSSH.MethodsA series of 72 patients with upper extremity disorders completed the QuickDASH-JSSH, the 36-Item Short-Form Health Survey (SF-36), and the Visual Analog Scale (VAS) for pain. Thirty-eight of the patients were reassessed for test–retest reliability 1 or 2 weeks later. Reliability was investigated by the reproducibility and internal consistency. To analyze the validity, a principal component analysis and the correlation coefficients between the QuickDASH-JSSH and the SF-36 were obtained. The responsiveness was examined by calculating the standardized response mean (SRM; mean change/SD) and effect size (mean change/SD of baseline value) after carpal tunnel release of the 17 patients with carpal tunnel syndrome.ResultsCronbach’s alpha coefficient in the QuickDASH-DS was 0.88. The intraclass correlation coefficient (ICC) for the same was 0.82. The unidimensionality of the QuickDASH-DS was confirmed. The correlation coefficients between the QuickDASH-DS and the DASH-DS, DASH-W, or the DASH-SM were 0.92, 0.81, or 0.76, respectively. The correlation coefficients between the QuickDASH-DS score and the subscales of the SF-36 ranged from −0.29 to −0.73. The correlation coefficient between the QuickDASH-DS score and the VAS for pain was 0.52. The SRM/effect size of QuickDASH-DS was −0.54/−0.37, which indicated moderate sensitivity.ConclusionThe Japanese version of QuickDASH has equivalent evaluation capacities to the original QuickDASH.

High prevalence of wild-type transthyretin deposition in patients with idiopathic carpal tunnel syndrome: a common cause of carpal tunnel syndrome in the elderly

Carpal tunnel syndrome is the most common type of entrapment neuropathy. However, the cause of carpal tunnel syndrome remains unclear in most cases. Senile systemic amyloidosis, induced by wild-type transthyretin deposition, is a prevalent aging-related disorder and often accompanied by carpal tunnel syndrome. In this study, we measured the frequency of unrecognized wild-type transthyretin deposition in patients with idiopathic carpal tunnel syndrome. One hundred twenty-three patients with carpal tunnel syndrome, including 100 idiopathic patients, treated by carpal tunnel release surgery were analyzed. Tenosynovial tissues obtained at surgery were analyzed by Congo red and immunohistochemical staining. If staining for transthyretin was positive, the entire transthyretin gene was analyzed by direct DNA sequencing. We also analyzed tenosynovial tissues from 32 autopsy cases as controls. Thirty-four patients (34.0%) with idiopathic carpal tunnel syndrome showed amyloid deposition in the tenosynovial tissue, and all amyloid showed specific immunolabeling with antitransthyretin antibody. Direct DNA sequencing of the entire transthyretin gene did not reveal any mutations, indicating that all amyloid deposits were derived form wild-type transthyretin. Statistical analysis using logistic regression showed that the prevalence of transthyretin deposition in the idiopathic carpal tunnel syndrome group was significantly higher than that in controls (odds ratio, 15.8; 95% confidence interval, 3.3-5.7), and age and male sex were independent risk factors for transthyretin amyloid deposition. Our results demonstrate that wild-type transthyretin deposition is a common cause of carpal tunnel syndrome in elderly men. It is likely that many patients develop carpal tunnel syndrome as an initial symptom of senile systemic amyloidosis.