Masafumi Ishizuki

Traumatic and spontaneous dislocation of extensor tendon of the long finger

Extensor tendon dislocation is an unusual problem in patients unaffected by rheumatoid arthritis. Sixteen cases of ulnar dislocation of the long extensor tendon of the long finger are reported. Five of these cases were classified as traumatic dislocation and 11 as spontaneous dislocation. All cases were treated by surgery. Differences in anatomic and clinical features between traumatic and spontaneous dislocation of the long extensor tendon are described.

Prediction of primary reparability of massive tears of the rotator cuff on preoperative magnetic resonance imaging

We studied magnetic resonance images of rotator cuff tears to determine whether it was possible to establish preoperatively the feasibility or infeasibility of primary repair. The study comprised 27 shoulders in 26 patients who underwent magnetic resonance imaging before surgery because of complete tears of the rotator cuff and who were treated with primary repair or by the patch graft technique because primary repair was not feasible. The length and width of each tear, the thickness of the supraspinatus muscle at the superior margin of the glenoid, and the presence or absence of a high signal intensity in the infraspinatus muscle were statistically analyzed. Primary repair was often not feasible when both the length and width of the tear exceeded 40 mm on a preoperative magnetic resonance image, when the supraspinatus muscle was thin at the superior margin of the glenoid, and when a high signal intensity was observed in the infraspinatus muscle.

Injury to collateral ligament of the metacarpophalangeal joint of a finger

Twenty-two patients with injury to the collateral ligament of the metacarpophalangeal (MP) joint of a finger are reported. Thirteen cases were acute injuries and nine cases were chronic injuries. In all cases arthrography was performed. The arthrographic findings correlated with the grade of joint stability. Arthrographics of the unstable joint gave useful information for elucidating the mechanism of injury and deciding whether surgical treatment was indicated. At exploratory surgery, a Stener lesion was identified in one case in which the ruptured end of the ligament was trapped by the proximal portion of the expansion hood and sagittal band.

Experimental study on nerve regeneration through the basement membrane tubes of the nerve, muscle, and artery

We evaluated neurotization after transplantation with lyophilized nerves, muscles, and arteries, and examined the possibility of practical application of long bridging grafts. Grafts of 10 mm and 25 mm of lyophilized nerves, muscles, and arteries harvested from Fisher rats were transplanted to the sciatic nerves of recipient Lewis rats. The histological changes undergone by short grafts were observed at weekly intervals. The sham‐operated and isograft groups were used to compare the results of long grafts. In both the nerve and muscle‐graft group, regenerated axons grew out through the residual basement membrane tube. But in the muscle graft group, phagocytosis of myofibril debris took longer than that of degenerated axons. No statistical differences were found between results of TSI, induced EMG, and quantitative analysis of myelinated axons in the nerve and muscle graft groups. No neurotization was noted in the long artery graft. In long grafts, laminin found on the basement membrane may not be sufficient to accelerate neurotization, and arteries should not be used for tubulization.

Positional dislocation of the pisiform

Positional dislocation of the pisiform repeatedly occurred in the right wrist of a 19-year-old man following a motorcycle accident. The pisiform repeatedly dislocated distal to the triquetrum when the wrist was extended to 45 degrees or more, and the pisiform was reduced to proper joint congruity after wrist flexion of 55 degrees or more. The patient had a background of generalized joint laxity. Resection of the pisiform resulted in a pain-free, fully functional wrist.

Hyperextension Injuries of the MP Joint of the Thumb

We report 26 cases of hyperextension injury of the MP joint of the thumb. These were classified into the following three categories; dorsal dislocation of the MP joint or volar plate avulsion; locking of the MP joint and fracture of the sesamoid bone. We report the pathomechanics and clinical features of these injuries.

Antinociceptive effects of tizanidine, diazepam and eperisone in isolated spinal cord-tail preparations of newborn rat

&NA; Antinociceptive effects of three centrally acting muscle relaxants, tizanidine, diazepam and eperisone, were studied using an isolated newborn rat spinal cord‐tail preparation. Potentials were recorded from a lumbar ventral root (L3–L5) cxtracellularly using a suction electrode. Pinch stimulation applied to the tail elicited a depolarizing response in the ventral root lasting 15/2–30 sec, referred to as the tail‐pinch potential. Electrical stimulation of the ipsilateral dorsal root of the same segment with a single shock induced depolarizing responses in the ventral root. The responses consisted of monosynaptic and polysynaptic reflexes with a fast time course, followed by a slow depolarizing response lasting about 20 sec. The latter slow response was designated the ipsilateral slow ventral root potential (VRP). Both the tail‐pinch potential and the ipsilateral slow VRP were depressed by application to the spinal cord of tizanidine (2–3 &mgr;M), diazepam (2 &mgr;M) and eperisone (100–200 &mgr;M). The effect of tizanidine was reversed by &agr;2‐adrenoreceptor antagonists, yohimbine and idazoxan, but not by an &agr;1‐antagonist, prazosin. The effect of diazepam was reversed by the benzodiazepine antagonist, flumazenil.

Stener-like lesions of collateral ligament ruptures of the metacarpophalangeal joint of the finger

BackgroundThe Stener lesion of the ulnar collateral ligament of the metacarpophalangeal (MP) joint of the thumb is characterized by an interposition of the adductor aponeurosis between a distally avulsed ligament and its insertion into the base of the proximal phalanx. Stener-like lesions of the MP joint of the finger have been previously reported in only a few cases.MethodsThe authors experienced 38 cases of collateral ligament injuries of the MP joint of the finger. The two most frequently affected sites were the radial side of the little finger (21 cases) and the radial side of the ring finger (8 cases). We have previously reported some of these cases (22 cases), as well as clinical features and arthrographic findings. One Stener-like lesion in a collateral ligament injury of the MP joint of the ring finger was also reported earlier (Ishizuki, 1988). Additionally, Stener-like lesions were found postoperatively in six of eight cases surgically treated for collateral ligament injuries of the MP joint of the finger (little finger involvement in 5 cases and long finger involvement in 1 case).ResultsWe experienced six cases of a Stener-like lesion of the MP joint of the finger. In five of these cases the distally avulsed collateral ligament was trapped by the opened window of the injured sagittal band. In the other case the ligament was avulsed at a proximal site, and the ruptured end was trapped by the sagittal band. All of the little fingers involving Stener-like lesions were abducted and unable to adduct. Therefore, an abducted little finger is an important sign of this lesion and is considered to warrant surgical treatment. Arthrograms provided information useful for identifying the lesions. In the radial three fingers, palpation of the tumor at the level of the collateral ligament may also be an important examining tool for identifying a displaced ruptured collateral ligament of the MP joint of the finger.ConclusionWe experienced six cases of Stener-like lesions of the MP joint of the finger. In all cases, the avulsed collateral ligament was trapped by the ruptured sagittal band. Surgical treatment was thought to be indicated in these cases. Therefore, it is important to avoid overlooking Stener-like lesions of the MP joint of the finger.

Extensor digitorum brevis manus associated with attrition rupture of a common extensor tendon

A 65-year-old Japanese housewife ruptured the common extensor tendon of her left ring finger. This is thought to be caused by the associated digitorum brevis manus.

Clinical application of sapphire pins as an internal fixation device for the upper extremity

Since June 1980, sapphire pins (monocrystalline alumina ceramic pins) have been used in 22 patients as an internal fixation device for hand and elbow problems. In our follow-up studies, good bone healing was observed in all cases except for one delayed union in a fracture of the diaphysis of the proximal phalanx. Radiographs showed no pin migration or osteolytic reaction around the pins. We therefore conclude that our device and its insertion technique can be successfully applied to intraarticular fractures and fractures in the vicinity of the joint.