Inferior Pole Sleeve Fracture of the Patella in an Adolescent: A Case Report.

An 11-year-old boy was admitted to our hospital due to severe pain in his right knee when he landed after jumping over a vaulting box. A plain X-ray image and computed tomography scan showed an avulsion fracture of the lower pole of the patella and patella alta. Furthermore, magnetic resonance imaging (MRI) revealed an articular cartilage lesion and rupture between the inferior pole of the patella and the patella tendon. We diagnosed a sleeve fracture of the patella and performed surgical treatment. Open reduction and internal fixation were performed by the pull-out technique using transosseous no. 2 MaxBraid™â€‹â€‹â€‹â€‹â€‹â€‹ ​(Zimmer Biomet, Tokyo, Japan) sutures. While postoperative weight-bearing was permitted, the knee joint was immobilized in a brace for four weeks. Three months of postoperative assessment revealed excellent functional outcomes.

Brachialis Muscle Rupture in a Pediatric Patient Followed Up by Ultrasound Examinations: A Rare Case Report.

Isolated brachial muscle injuries are relatively rare injuries and reportedly occur during forced elbow extension. Though commonly conservative treatment approach is adopted, the treatment criteria remain unclear. Here, we report the case of a patient who experienced functional recovery after conservative treatment for an isolated brachial muscle injury. The patient was an 8-year-old boy whose chief complaint was left elbow pain. The injury occurred when the patient fell while playing on gymnastics bars and bruised the palmar side of his left elbow on the bar. Owing to the pain in the left elbow, the patient came to our institution. There were no clear signs of deformities or swelling in the left elbow and no obvious tenderness. X-ray and computed tomography (CT) imaging examinations revealed no signs of a fracture or dislocation, and the patient was diagnosed with left brachialis muscle rupture based on magnetic resonance imaging (MRI). Although the brachialis muscle was complete ruptured, a healing tendency was seen on body surface ultrasound examinations over time, and the patient was treated conservatively. After 3 weeks of cast immobilization, the patient underwent range of motion exercises. Two months after the injury, there were no issues with elbow joint function in daily life activities and no limitations in range of motion. Here, MRI was used to diagnose brachialis muscle rupture, and ultrasound examinations were utilized to make treatment decisions.

Flexor Pollicis Longus Tendon Rupture and Carpal Tunnel Syndrome due to Scaphoid Nonunion Advanced Collapse: A Case Report.

CASE: We report a case of flexor pollicis longus (FPL) tendon rupture and carpal tunnel syndrome due to scaphoid nonunion advanced collapse deformity. Intraoperative findings showed disruption of the palmar joint capsule and a sharp proximal bone fragment protruding into the carpal tunnel. Removal of this proximal fragment and tendon grafting were performed. At the postoperative 2-year follow-up, the patient had no wrist pain, finger numbness, or restriction of thumb motion. CONCLUSION: Our results suggest that minimally invasive surgical procedures, such as proximal pole or osteophyte resection, might be optimal choices for early rehabilitation after tendon repair in cases of FPL tendon rupture due to asymptomatic scaphoid nonunion.

Repair of peripheral nerve defect with direct gradual lengthening of the proximal nerve stump in rats.

We investigated the effect of direct gradual lengthening on the proximal nerve stump and subsequent nerve regeneration in rats. A 10-mm-long nerve segment was resected from the sciatic nerve of each rat. The proximal nerve stump was directly lengthened at a rate of 1 mm/day using an original external nerve distraction device. Experiment I: After distraction periods of 10, 15, and 20 days, the length of each nerve was evaluated, and the lengthened nerve stump was also examined by immunohistochemical analysis. Experiment II: After a distraction period of 20 days, both nerve stumps were refreshed and direct end-to-end neurorrhaphy was performed. For control, 10-mm nerve grafting was immediately performed after nerve resection. Nerve regeneration was evaluated electrophysiologically and histologically 7, 9, and 15 weeks after nerve resection in both groups. The whole proximal nerve stump, including the endoneurium and the axon, could be lengthened in proportion to the distraction period. There were no significant differences in motor nerve conduction velocity and tetanic muscle contraction force between both groups. Histologically, the total number of myelinated fibers was significantly greater in the nerve lengthening group than in the autografting group. This study demonstrated that the whole proximal nerve stump including the endoneurium and the axon could be lengthened by direct gradual distraction, and that this method might have potential application in the repair of peripheral nerve defects.

Pre-degenerated nerve shows enhanced regeneration after incremental elongation in rats.

Following nerve degeneration, we investigated effects of linear elongation on subsequent nerve regeneration in a total of 92 Wistar rats (weight 380-430 g). The nerve was ligated at the midthigh and then elongated incrementally by a total of 15 mm by leg lengthening at a rate of 3 or 5 mm/day. Seven days after initiation of nerve elongation, the external fixator was removed and normal leg length was restored with internal fixation. Then a 10 mm nerve segment at the ligature site was excised, and the nerve was repaired with sutures (group D). At 2, 4, 6, and 8 weeks after nerve suturing, we examined transverse semi-thin nerve sections compared with group I (severed and repaired after leg lengthening without a nerve ligature) and control group (severed and repaired without leg lengthening). After lengthening at 3 mm/day, nerve regeneration in group D was enhanced at 4 weeks. After lengthening at 5 mm/day, nerve regeneration in group D also was enhanced at 6 and 8 weeks. Pre-degenerated nerve showed better regeneration after suturing than intact nerve. Elongation holds promise as an alternative to nerve grafting in treatment of nerve injury.

Internodes can nearly double in length with gradual elongation of the adult rat sciatic nerve.

Leg lengthening procedure is used increasingly to treat leg length discrepancy and some forms of dwarfism. We investigated adaptation in rat sciatic nerve to the gradual nerve elongation that occurs with leg lengthening. Indirect nerve elongation was produced by leg lengthening by a total of 15, 30, 45, or 70 mm at a rate of 1 mm/day. One day after leg lengthening completion, transverse semithin sections of sciatic nerve were prepared and examined; a teased-fiber study also was performed. Elongation decreased axon diameter, but not significantly. In teased-fiber preparations, internodal length was increased by 93%, and the longest internode measured 3000 microm after leg lengthening by 70 mm. Slopes of fiber diameter-internodal length regression lines increased with increasing elongation. Paranodal demyelination caused by nerve elongation worsened as elongation increased, stimulating remyelination (i.e., intercalation of a segment). Only 0.8% of axons showed degeneration in the group with 70 mm of elongation. We concluded that adult rat sciatic nerve can adapt itself to leg lengthening procedure with even doubling internodal length.

Repair of peripheral nerve defect by direct gradual lengthening of the distal nerve stump in rats: cellular reaction.

We investigated the effects of direct gradual lengthening of the distal stump of a peripheral nerve and subsequent nerve regeneration in rats. A segment 10 mm long was resected from rat sciatic nerve. The distal nerve stump was fixed to a ring and pulled directly at a rate of 1 mm/day using an original external nerve distraction device. After distraction for 10, 15, and 20 days, the lengthened nerves were evaluated macroscopically and immunocytochemically. At day 20, the mean (SD) distances from the ring to the 3 mm and 6 mm distal part, which were marked with sutures on the epineurium, were 7 (0.5) mm and 12.1 (0.5) mm, respectively, and the number of Schwann cells in the lengthening group had increased to twice that of control group. The distal stump of a peripheral nerve including the epineurium, endoneurium, and proliferation of Schwann cells can be lengthened directly. This method also made it possible to lengthen the nerve stump longitudinally and to control both the rate and distance. We think that this method may be used in the treatment of peripheral nerve injury.

Repair of peripheral nerve defect by direct gradual lengthening of the distal nerve stump in rats: effect on nerve regeneration.

We investigated the use of direct lengthening of the distal stump of a peripheral nerve to compare the results of nerve regeneration using the direct lengthening method with simple end-to-end suture and autografting in rats. A segment 10 mm long was resected from the rat sciatic nerve (n=18 in each group). The distal nerve stump was fixed to a ring and pulled at a rate of 1 mm/day for 20 days using an original external nerve distraction device. The results showed that the degree of nerve regeneration in the lengthened group was superior to that of the grafted group electrophysiologically and histologically, but there were no significant differences between the lengthened and end-to-end suture groups. We conclude that direct lengthening of the distal stump of a peripheral nerve can promote nerve regeneration similar to that observed in a Wallerian degenerated nerve. We think that this technique may be used for the treatment of peripheral nerve injuries.

Distribution of sodium channels during nerve elongation in rat peripheral nerve.

A number of studies have investigated electrophysiological and morphological changes of peripheral nerves during gradual elongation. There has been, however, no report on the distribution of sodium channels at Ranvier's nodes during peripheral nerve elongation. We investigated peripheral nerve injury after the gradual elongation of rat sciatic nerves. Indirect nerve elongation was induced by leg lengthening at a rate of 3 mm/day by 15 or 30 mm. At 7 days after the leg lengthening, the electrophysiological properties of sciatic nerves, the ultrastructures of the Ranvier's nodes and axons, and the distribution of voltage-dependent sodium channels were examined. In the control nerves, most sodium channels were localized at Ranvier's nodes in myelinated axons, providing the physiological basis of saltatory conduction. In the elongated nerves, both the amplitude and conduction velocity of compound nerve action potential decreased following leg lengthening. The elongated nerves also showed paranodal demyelination in Ranvier's nodes longer than those in the control group. In addition, the distribution of sodium channels became diffuse or disappeared at Ranvier's nodes of elongated nerves. The diffuse distribution and/or disappearance of sodium channels may underlie the electrophysiological changes in compound nerve action potential induced by nerve elongation.

Paranodal demyelination by gradual nerve stretch can be repaired by elongation of internodes.

Nerve elongation resulting from leg-lengthening surgery can be injurious. We investigated peripheral nerve injury and recovery after gradual elongation of the rat sciatic nerve by progressive stretching. Indirect nerve elongation was produced by leg lengthening by 15 mm, at a rate of 3 mm/day (group I) or 5 mm/day (group II). The elongated length was then maintained. At 0 weeks, representing the 7th day after starting leg lengthening, and at weeks 2, 4, and 6, transverse semithin sections of sciatic nerve were examined. At the same time a teased fiber study was performed. As a result of nerve elongation axon diameter was decreased, although it later recovered. Axon diameter recovered more slowly in group II than I. Myelin thickness did not change compared with controls. In the teased fiber study, internodal length was increased by about 10% after nerve elongation in each group. Almost all nerve fibers showed demyelination at 0 weeks; myelination recovered with time, more slowly in group II than I. More obvious demyelination, axonal degeneration, and remyelination were observed in group II. We conclude that mild demyelination was repaired by elongation of internodes, while more severe demyelination was repaired by intercalation of segments.

P0 mRNA expression increases during gradual nerve elongation in adult rats.

Leg lengthening with nerve elongation is a common clinical treatment. We investigated morphological and molecular changes in peripheral nerves associated with femoral lengthening using animal models. Sciatic nerves of 13 week old male Wistar rats (n = 35) were elongated indirectly by leg lengthening for 14 days at 1 mm/day. At 3, 7, 14, 21, and 35 days following initiation of elongation, sciatic nerves on the elongated side and contralateral (control) side were excised at the midpoint of the femur. Internodal length was increased by 17%. Light and electron microscopic observation of transverse sections at 14 days showed elongated nerves appearing similar to control nerves with no degenerating axons and normal myelin thickness. We next examined changes of mRNA expression of a major myelin glycoprotein, P0, in elongated nerves using a quantitative reverse transcription-polymerase chain reaction and in situ hybridization. P0 mRNA expression in elongated nerves was increased during the first 3 weeks, with expression reaching 160% of control nerve expression at 14 days. Results of in situ hybridization were confirmatory. We concluded that myelin synthesis occurred during gradual nerve elongation. In adulthood, Schwann cells retain ability to synthesize myelin in response to nerve stretching.