Hand Surgery

We studied in vivo dynamic shape changes of the interasseous membrane (IOM) during forearm rotation using three-dimensional magnetic resonance imaging (3D-MRI), and simultaneously analysed 3D-motion of the forearm rotation. Wavy deformities were seen in the IOM in the pronated position, and similar small changes were also seen at maximum supination (average 82°) and in the neutral position. These dynamic changes mainly occurred in the membranous part of the IOM, whereas the tendinous part demonstrated minimal dynamic changes during rotation in all subjects. On the dorsal aspect, deformity around the dorsal oblique cord was seen at maximum pronation. From this 3D-MRI observation, the tendinous part is considered to be taut during rotation to provide stability between the radius and ulna, because of its straightness and less dynamic changes. The more deformable membranous part is important to allow for smooth rotation, since it lies at a distance from the rotation axis. Inelasticity developing in the membranous part from trauma may pre-dispose to pronation-supination contracture. The radius rotated around the ulna from maximum supination to 45° pronation. At maximum pronation (average 75°), the radius translated average 1.8 mm palmarly and rotated average 4.0° ulnarward on the ulna. Incongruity of the distal radioulnar joint, contraction of the pronator quadratus and torsion between the radius and ulna at maximum pronation may produce this irregular motion of the radius and cause the dynamic changes of the IOM.

This study describes the health status of 31 patients who underwent recessional ulnar osteotomy for ulnocarpal impingement. An additional lunotriquetral fusion was performed in 11/31 patients for joint degeneration. Outcomes included the DASH (Disability of arm, shoulder and hand) questionnaire, SF-36 Acute Health Survey, complications, and satisfaction with surgical outcome. Patients were stratified into two groups for analysis: osteotomy alone and osteotomy + fusion. The overall results indicated that osteotomy plus fusion in patients with more advanced ulnocarpal impingement did not equalise patients' post-operative health status to that reported by patients requiring osteotomy alone. Mean DASH and SF-36 physical component scores indicated better health status in the osteotomy group compared with the osteotomy + fusion group after surgery. Forty-one point nine per cent of patients required plate removal, and scar pain persisted in 58%. One patient in each group developed a non-union requiring revision surgery. Patients in both groups were generally satisfied with their surgical result, with a higher proportion of very or completely satisfied patients in the osteotomy group (65%) compared to the osteotomy + fusion group (27%). Overall, recessional ulnar osteotomy appears to be a successful procedure for the treatment of ulnocarpal impingement.

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.

Six cases of symptomatic cystic lesions of carpal bones which underwent operative treatment were reviewed. Definite diagnosis, etiology and treatment were also discussed. The lesions occurred in the scaphoid, lunate, capitate and triquetrum, and were multiple lesions in four of the six cases. Juxta-articular bone cyst was diagnosed in three cases: intraosseous cavity surrounded by fibrous membrane containing gelatinous material, and "bone cyst-like pathologic change" in three cases which contained fibrous connective tissue resembled the thick inner wall of juxta-articular bone cyst histologically. They were treated by curettage and cancellous bone grafting; the outcomes were favourable without complication. It is suggested that the minor trauma resulting from the carpal loading serves as a basis for intraosseous lesion, which initiates intramedullary metaplasia followed by fibrous connective tissue proliferation with/without mucin secretion, and forms cystic cavity.

We report the use of a hypothenar pedicled fat flap to cover the median nerve in recalcitrant carpal tunnel syndrome. Forty-five patients with recurrent symptoms after previous carpal tunnel surgery were included in this study. Patients with incomplete release of the transverse carpal ligament were not included.

We performed an anatomical study on 30 cadavers. The original technique with the section of the deep branch of ulnar artery was modified. The flap could be transferred onto the median nerve without stretching. The median follow-up was 45 months (range, 12–80 months). Pain completely disappeared in 41 patients with normal nerve conduction. Based on clinical and electromyographic signs, the global results showed excellent results (49%), 19 good results (45%), two average results (4.5%) and two failures (2%).

The use of a hypothenar pedicled fat flap to cover the median nerve in recalcitrant carpal tunnel syndrome is a simple and efficient technique which improves the trophic environment of the median nerve and relieves pain.

The purpose of this study was to clarify how fast the peripheral nerve can be elongated gradually without inducing nerve conduction block, and to assess whether the damage to the peripheral nerve is reversible. Rabbit femur was gradually elongated to 30 mm at the rate of 0.8 mm/day, 2.0 mm/day, and 4.0 mm/day to stretch the sciatic nerve. Immediately after and eight weeks after elongation, each group was estimated. Elongation of the Ranvier's node, which was likely the cause of conduction block, was observed and its severity increased with elongation speed. There was no Wallerian degeneration even when conduction block was complete. There was little damage to the sciatic nerve in the group of 0.8 mm/day. Damage in the group of 2.0 mm/day immediately after elongation had a tendency to recover by eight weeks, but there was no such tendency in the group of 4.0 mm/day.

Abnormal anatomy of carpal bones is uncommon. We report on a multitrauma patient that, was initially misdiagnosed as scaphoid dislocation, which later was proven to be pisiform hamate coalition.

Congenital pseudarthrosis of the ulna is very rare. We have experienced a case of pseudarthrosis of ulna to be treated with the vascularized fibular graft in a seven-years-and-three-month-old boy.

We describe a case of anomalous muscle belly at Guyon's canal causing ulnar tunnel syndrome with sparing of the motor branch and hypothenar muscles.