Intraligamentous Hematoma of the Anterior Cruciate Ligament.

Lesions of the anterior cruciate ligament (ACL) are rare entities in clinical practice. Here, we present the case of an intraligamentous hematoma of the ACL. A 20-year-old man (height 173 cm, weight 62.9 kg, body mass index 21) with no significant past medical history developed progressively worsening pain and limitation of range of motion in the left knee due to minor trauma. No abnormality was found on plain radiography; however, magnetic resonance imaging revealed a cystic lesion in the intercondylar fossa that was hypointense on T1-weighted imaging and hyperintense on T2-weighted imaging. We performed knee arthroscopy, made a longitudinal incision in the anterior aspect of the ACL, and identified a hematoma. The patient's postoperative course was uneventful. There is no evidence of recurrence at one year after surgery. Although the ACL is a relatively hypovascular structure, it does contain microscopic blood vessels. In this case, we speculate that the intraligamentous hematoma was the result of rupture of these very small blood vessels in response to a minor injury.

Fiber-optic simultaneous distributed monitoring of strain and temperature for an aircraft wing during flight.

We applied a fiber optic distributed simultaneous strain and temperature measurement technique to the structural monitoring of the main wing of a middle-sized passenger jet aircraft during flight. We used 40 10 cm long fiber Bragg gratings (FBGs), inscribed in a highly birefringent polarization-maintaining fiber. The FBGs were interrogated by optical frequency domain reflectometry, which could measure Bragg wavelength distributions at a sampling rate of 151 Hz. The simultaneous measurement technique could detect structural behaviors of the wing during flight under temperature-changing conditions. In addition, we discuss the effect of the polarization mode-coupling and the apparent position shift of the FBGs over time, which occurred during flight.

Pedicled unipolar latissimus dorsi flap for reconstruction of finger extensor.

We describe the use of a pedicled unipolar latissimus dorsi flap to restore finger extension. The patient had large defects in the radial nerve and extensor musculature. A long-tailed, 50-cm-long flap was prepared, which enabled the end of the flap to be sutured to the extensor digitorum.

Vibration monitoring of a helicopter blade model using the optical fiber distributed strain sensing technique.

We demonstrate a dynamic distributed monitoring technique using a long-length fiber Bragg grating (FBG) interrogated by optical frequency domain reflectometry (OFDR) that measures strain at a speed of 150 Hz, spatial resolution of 1 mm, and measurement range of 20 m. A 5 m FBG is bonded to a 5.5 m helicopter blade model, and vibration is applied by the step relaxation method. The time domain responses of the strain distributions are measured, and the blade deflections are calculated based on the strain distributions. Frequency response functions are obtained using the time domain responses of the calculated deflection induced by the preload release, and the modal parameters are retrieved. Experimental results demonstrated the dynamic monitoring performances and the applicability to the modal analysis of the OFDR-FBG technique.

Distributed strain measurement based on long-gauge FBG and delayed transmission/reflection ratiometric reflectometry for dynamic structural deformation monitoring.

In this paper, we propose a delayed transmission/reflection ratiometric reflectometry (DTR(3)) scheme using a long-gauge fiber Bragg grating (FBG), which can be used for dynamic structural deformation monitoring of structures of between a few to tens of meters in length, such as airplane wings and helicopter blades. FBG sensors used for multipoint sensing generally employ wavelength division multiplexing techniques utilizing several Bragg central wavelengths; by contrast, the DTR(3) interrogator uses a continuous pulse array based on a pseudorandom number code and a long-gauge FBG utilizing a single Bragg wavelength and composed of simple hardware devices. The DTR(3) scheme can detect distributed strain at a 50 cm spatial resolution using a long-gauge FBG with a 100 Hz sampling rate. We evaluated the strain sensing characteristics of the long-gauge FBG when attached to a 2.5 m aluminum bar and a 5.5 m helicopter blade model, determining these structure natural frequencies in free vibration tests and their distributed strain characteristics in static tests.

Reverse adipofascial flap after resection of a malignant perineurioma of the forearm.

The authors describe a patient with recurrent perineurioma arising in the subcutaneous tissue of the dorsal forearm and extending along the forearm fascia. Soft tissue perineurioma is a rare, originally benign peripheral nerve sheath neoplasm arising from the perineurium, a protective cell barrier surrounding the individual fascicles in peripheral nerves. Perineurioma has only recently been recognized as an entity distinct from other nerve sheath tumors, such as schwannoma and neurofibroma, with unique morphologic, ultrastructural, and immunoreactive features. The recurrent tumor had converted into malignant perineurioma, defined as increased nuclear pleomorphism and cellularity. The ill-marginate feature extending along the fascia required wide resection, leaving a substantial defect on the distal forearm. Surgical repair of large forearm skin defects is challenging because of limited skin extensibility for flap creation, the prominence of the site in terms of aesthetic outcome, and the risk of damage to extrinsic muscles that control delicate hand movements. The reverse forearm adipofascial flap, which was based on distal perforators of the radial artery, was suitable for the current case to cover the exposed myotendinous junctions of the forearm extensor muscles. This flap did not sacrifice skin, a major vessel, or skeletal muscles, and preserved function at both the donor and the recipient sites. The texture of the graft was similar to that of the surrounding skin. The clinical and histopathologic features of this rare tumor are also described to aid in the differential diagnosis and as a reference for surgeons who treat soft tissue neoplasms and may encounter this type of soft tumor.

Signal processing method based on group delay calculation for distributed Bragg wavelength shift in optical frequency domain reflectometry.

A signal processing method based on group delay calculations is introduced for distributed measurements of long-length fiber Bragg gratings (FBGs) based on optical frequency domain reflectometry (OFDR). Bragg wavelength shifts in interfered signals of OFDR are regarded as group delay. By calculating group delay, the distribution of Bragg wavelength shifts is obtained with high computational efficiency. We introduce weighted averaging process for noise reduction. This method required only 3.5% of signal processing time which was necessary for conventional equivalent signal processing based on short-time Fourier transform. The method also showed high sensitivity to experimental signals where non-uniform strain distributions existed in a long-length FBG.

Irreducible fracture dislocation of a finger metacarpophalangeal joint: a case report.

A case of unusual displacement in a finger, with an avulsion fragment from the dorsal metacarpal head of the finger displaced in the palmar direction under the volar plate is described. An 18-year-old woman presented with complaint of difficulty flexing the metacarpophalangeal (MP) joint of the right little finger after a fall onto the outstretched hand. Three-dimensional computed tomography (CT) was useful for diagnosing this condition. Use of both palmar and dorsal approaches was needed to reduce the displacement and to fix the bones with a single screw. Bone union was achieved, and the patient has been asymptomatic for more than 10 months.