Yukio Nakatsuchi

Mechanism of limitation of pronation/supination of the forearm in geometric models of deformities of the forearm bones

OBJECTIVE To clarify the mechanism of limitation of pronation/supination of the forearm associated with the angular deformity of the forearm bones and narrowing of the interosseous space. DESIGN A three-dimensional geometric model of the forearm bones with the interosseous membrane and its axial section were used. BACKGROUND Limitation of pronation/supination associated with the deformity of the forearm bones is one of the significant problems encountered in the treatment of the forearm fracture. Elucidation of its mechanism is important for its prevention and treatment. METHODS In the axial section, the effects of the positional relationship between the axis of pronation/supination and the forearm bones on the range of pronation/supination was studied using analytic geometry in each model with non-narrowing or narrowing of the interosseous space. Subsequently, in the three-dimensional model each forearm bone with the same angular deformity, the direction and magnitude of the angular deformity which would lead to limitation of pronation/supination were calculated using analytic geometry. Each parameter of the models was obtained by the radiographic measurements of the normal forearms. RESULTS When the axis of the pronation/supination passed through the interosseous region (less than 2 cm radioulnarly and 0.8 cm anteroposteriorly) in the model of the axial section without narrowing of the interosseous space, more than 40 degrees of pronation and supination were possible. When the axis deviated from this region, significant loss of pronation/supination was observed associated with restriction by the interosseous membrane rather than impingement. Furthermore, the area of this region decreased according to narrowing of the interosseous space with shortening of the interosseous membrane. In the three-dimensional model, the direction and magnitude of the angular deformity which would lead to significant loss of pronation/supination was more than 14 degrees radially, 7 degrees ulnarly, 5 degrees anteriorly, 4 degrees posteriorly. CONCLUSIONS The positional relationship between the axis of pronation/supination and the forearm bones with the interosseous membrane may play an important role regarding pronation/supination of the forearm. RELEVANCE Evaluation of the bone deformities based on understanding this mechanism of limitation of pronation/supination would lead to an appropriate treatment of malunion of the forearm bones.

Conservative Treatment of Thoracic Outlet Syndrome Using an Orthosis

We describe a strapping device for elevation of the shoulder in patients with thoracic outlet syndrome (TOS). The device was used by 86 patients with TOS whose symptoms had been alleviated by passively raising the shoulder. Symptoms of TOS were classified as proximal, including pain in the shoulder girdle, and distal, in which there were neurological deficits related to the brachial plexus. The device was more effective in patients with distal symptoms: pain disappeared or improved in 67% of patients; numbness in 85%; sensory disturbance in 84%; and motor disturbance in 80%. However, proximal symptoms were relieved in only 65% of the patients. The ability to perform activities of daily living was rated as excellent in 33% of patients, good in 44%, fair in 12%, and poor in 9%. The shoulder orthosis described in this report can counterbalance downward traction on the brachial plexus and reduce the tension on it, thereby relieving symptoms of TOS.

Assessment of fracture healing in the tibia using the impulse response method.

The resonant frequency of a long bone as measured using the impulse response method (IRM) can reflect the bending rigidity of the bone. A study was performed using IRM to quantitatively assess fracture healing in 67 tibial fractures. A temporary decrease in resonant frequency early in the treatment course was found in 55.6% of tibias, most frequently in the cases treated by external fixation (83.3%) and the AO plate (80%). The resonant frequency also decreased temporarily following the removal of the fixation devices in 76% of the tibias where they were removed. The resonant frequency of the fractured tibia at the final follow-up exceeded that of the contralateral side in 18% of tibias, approached within 20 Hz in 11.5%, and did not reach within 20 Hz in 70.5%. A questionnaire on the effectiveness of the IRM examination in the treatment of the tibia fractures was completed by the treating orthopaedic surgeons. The IRM examinations were found to be very useful in 58.2% of cases, useful in 31.3%, and useless in 10.4%. Thus, IRM examinations are most helpful when they are able to detect the change in bending rigidity early in the treatment of tibia fractures.

Anatomical and Radiological Evaluation of the Triangular Fibrocartilage Complex of the Wrist

109 wrists from 69 cadavers (mean age 74 years) have been studied to clarify the pathology and morphology of the triangular fibrocartilage complex (TFCC) and to correlate pathological and radiological findings. Perforation of the TFCC was observed in 65% of the specimens and was considered to be secondary to a degenerative process, because it was often accompanied by degenerative changes in the ulnar carpal bones and perforation of the lunotriquetral ligament. To detect TFCC perforations on plain postero-anterior radiographs, it is important to evaluate ulnar plus variance and degenerative changes in the ulnar carpus. Existence of ulnar plus variance alone is more sensitive but less specific in detection of TFCC perforation than the existence of degenerative changes in the ulnar carpus.

Osteoid Osteoma of the Terminal Phalanx

The occurrence of osteoid osteoma in the hand is rare, and the rarest of all locations is the terminal phalanx. An osteoid osteoma of the terminal phalanx of the middle finger in a twenty-four-year old woman is described. This case illustrated the very typical clinical and x-ray features of an osteoid osteoma, which made diagnosis and treatment of this rare clinical entity straightforward. On pathological examination, a bundle of nerve fibres was found in the lesion, an explanation that the pain of this tumour may have been mediated by the nervous system via the nerve fibre.

Granular Cell Tumour of the Ulnar Nerve

Although granular cell tumours have been demonstrated to have a neural origin, they rarely arise in peripheral nerve trunks. We report a case of granular cell tumour of the ulnar nerve in a 51-year-old man. Though dissectable from the nerve, this intraneural tumour showed microscopic involvement of focal nerve fibres. This tumour tended to infiltrate the nerve in the same manner as a neurofibroma.

Funicular orientation by electrical stimulation and internal neurolysis in peripheral nerve suture

Eleven peripheral nerve lacerations around the wrists of ten patients were treated with funicular suture or nerve graft. In three freshly lacerated nerves funicular orientation could be made only by electrical stimulation to both cut ends. The electrophysiological method was also utilised to obtain funicular orientation of a proximal stump in eight old nerve lacerations. However, funicular orientation of the distal stump of old lacerations, which was not responsive to electrical stimulation, was performed anatomically by internal neurolysis from a terminal branching area up to a distal stump. By six months after the operation, motor and sensory functions of the patients with funicular suture had recovered to an excellent degree with rapid reinnervation.

Osteoporosis of the proximal humerus: Comparison of bone-mineral density and mechanical strength with the proximal femur

The hypothesis that the proximal humerus is more osteoporotic than the proximal femur has been examined by the indention test and bone-mineral density measurement on dissected proximal humeri and femora. The bone section at the base of the humeral head had about 65% of the bone-mineral density of the base of the femoral head. The energy required for 50% strain in the indention test on the humeral bone section was about 50% of that on the femoral head. The fact that the cancellous bone in the humeral head is more osteoporotic than in the femur may complicate surgical treatment of displaced humeral neck fractures.

An absence of structural changes in the proximal femur with osteoporosis

The hypothesis that osteoporosis occurs not as a preferential loss of the tensile trabeculae but as a general loss of bone was tested by using bone mineral densitometry and an indention test on dissected proximal femora. As osteoporosis advanced a significantly correlated decrease was found in both bone mineral density and mechanical properties between the principal compressive and tensile trabeculae. The decrease correlated with a decrease in the Singh index. These findings led to the conclusion that a sequential bone loss from the tensile trabeculae to the compressive ones did not occur as Singh reported, but instead a generalized loss of bone mineral in both the tensile and compressive trabeculae supervened. The structural changes, on which the grading system by Singh was based, were not observed in the proximal femur affected by osteoporosis.

Vein Grafting with the Telescoping Anastomotic Technique for Venous Defects

The telescoping anastomotic technique was used at both ends of autogenous vein grafts bridging a defect in slow-running, vulnerable veins. This was done on left epigastric veins of the rat, the central part of which was used as a graft. In the right epigastric veins, both the proximal and distal anastomoses were repaired using the conventional anastomotic technique. The overall patency rate of the grafts repaired with the telescoping anastomotic technique was 27/29 (93.3%) compared to 17/28 (60.7%) in the conventional group. The telescoping technique was also easier to perform than the conventional method.