鈴木 崇根

BACKGROUND: The ulnar collateral ligament complex, particularly the anterior oblique ligament (AOL), is mainly a static stabilizer controlling valgus. Various studies have been conducted on the kinematics of elbow joints after ligament cutting; however, no biomechanical studies have measured the tension applied to the ligament. Finite element modeling (FEM) is a very useful tool for biomechanical evaluation of the elbow. However, an accurate FEM of elbow joints cannot be developed without information on the potential tension of ligaments applied during the flexion and extension of elbow joints. We believe that FEM of the elbow joint could be obtained by measuring the material properties and potential tension of the ligament applied during the flexion and extension of the elbow joint. This study aimed to measure the potential tension and material properties of the ligament during the flexion and extension of the elbow, by identifying the relation between ligament length and tension using mechanical testing. METHODS: We included 10 elbows harvested from 7 fresh-frozen cadavers. The average age of the cadavers was 83.7 ± 5.65 years, and the samples included 8 elbows from 6 male cadavers and 2 elbows from 1 female cadaver. We measured the ligament length at each elbow angle by changing the elbow joint from 0° to 120° in 15° intervals. Thereafter, we extracted the AOL and divided into an anterior band (AB) and a posterior band (PB) and performed a mechanical test to calculate ligament stress. RESULTS: The ligament length of the AB gradually decreased as the flexion angle increased. Conversely, the ligament length of the PB gradually increased as the flexion angle increased. AB and PB lengths were approximately the same between 60° and 75°. The average ligament tension and stress of the AB gradually increased with elbow extension. In contrast, the average ligament tension and stress of the PB gradually increased with elbow flexion. The tension and stress of the AB and PB were balanced around the elbow joint at 60°. CONCLUSION: The AB was tenser on elbow extension, and the PB was tenser following elbow flexion. Also, the angle at which the AOL stress was equalized was 60°, suggesting that ∼60° is the angle at which the AOL is unlikely to be damaged.

It is important to know the relationship between flexor tendon traction force and applied finger flexion force generated during the rehabilitation of trigger finger. However, there has been no report on this relationship using the Jamar dynamometer in clinical practice and cadaveric study. Therefore, the purposes of this cadaveric study were to measure the value of flexion force when pulling a tendon via the method used in clinical practice and to investigate the relationship between the traction force of the flexor tendon and the flexion force of the finger output based on the Jamar dynamometer. In this study, each finger of a fresh-frozen cadaver was pulled, and the finger flexion force was measured with the Jamar Plus+ Digital Hand Dynamometer （Performance Health, Chicago, IL, USA）. There was a strong first-order correlation between the flexor tendon traction force and the finger flexion force, and the value of the finger flexion force［N］divided by the flexor tendon traction force［N］was 0.195-0.321. Under the same flexor tendon traction force, the exerted finger flexion force was in the following order: middle finger, index finger, ring finger, and little finger（maximum to minimum）. It is important to consider these findings when performing rehabilitation of trigger finger.

Purpose: Impaired thumb opposition associated with advanced carpal tunnel syndrome may be treated by opponensplasty at the time of open carpal tunnel release. However, it is unclear which opponensplasty technique achieves the greatest functional improvement. This study aimed to compare the biomechanics of thumb opposition after Camitz, modified Camitz, and Burkhalter opponensplasties. Methods: We used 6 fresh-frozen cadaveric arms. Each procedure was reproduced on each arm: Camitz opponensplasty, modified Camitz opponensplasty involving palmaris longus transfer routed around the flexor carpi ulnaris pulley, and Burkhalter opponensplasty. Arms were fixed with the wrist in 0° flexion and the forearm in neutral pronosupination, and sensors were placed on the thumbnail, radial styloid, and dorsal aspect of the second metacarpal head. The donor tendon was pulled using a mechanical testing machine with a maximum force of 25 N, and the locations of the sensors in thumb opposition were recorded. The first web space and thumb pronation angles were measured for each procedure and compared. Results: The mean first web space and pronation angles produced using 25 N were 55° and 20°, 57° and 26°, and 53° and 29° for the Camitz, modified Camitz, and Burkhalter opponensplasties, respectively. The first web space angle was significantly larger after modified Camitz opponensplasty compared with Burkhalter opponensplasty with 25 N loading. Camitz opponensplasty resulted in a significantly smaller pronation angle compared with modified Camitz and Burkhalter opponensplasties with 25 N loading. Conclusions: The modified Camitz opponensplasty produces a relatively balanced biomechanical outcome in terms of the first web space and pronation angles. Conversely, Burkhalter opponensplasty has been shown to be a favorable technique for improving pronation. Clinical relevance: Modified Camitz opponensplasty with a pulley offers effective restoration of thumb opposition, including pronation. On the other hand, Burkhalter opponensplasty represents a suitable option not only for patients with high median palsy and injury to the palmar aponeurosis but also for those who require improved pronation.

変形性関節症や関節リウマチに伴う遠位橈尺関節障害に対する尺骨頭切除術は良好な成績が報告されているが,橈尺骨間の不安定性による尺骨近位切除断端での痛みや伸筋腱断裂などの合併症が報告されている.尺骨頭切除後の橈尺骨間の不安定性や伸筋腱断裂のリスクについて,新鮮凍結屍体を用いて検討したので報告する.上腕中央で離断した1屍体の両上肢を使用し,専用の治具に固定した.橈尺骨に磁気位置センサーを設置し,各尺骨骨切り部における回内外運動時の橈骨の動きの変化を計測した.また前腕に重錘で負荷をかけ,伸筋腱断裂のリスクを評価した.その結果,尺骨骨切り位置が近位になるに従い橈尺骨不安定性が増大し,回内位で掌側・尺側に負荷をかけた場合に伸筋腱断裂のリスクがあることが示唆された.尺骨頭切除術を行う際はできるだけ遠位での尺骨骨切りを行い,術後には回内位での,特に掌側や尺側に負荷のかかる動作を避けるよう指導することで合併症を軽減できる可能性が示唆された.(著者抄録)

Purpose: Flexor digitorum profundus (FDP) dynamic tenodesis on the distal interphalangeal (DIP) joint is reported as a treatment for FDP tendon injuries. Although good clinical outcomes have been reported, biomechanical study results are unknown. This study aimed to evaluate the flexion range of motion in DIP and proximal interphalangeal (PIP) joints that have undergone dynamic tenodesis using fresh-frozen cadavers. Methods: We obtained 12 fingers from 3 fresh-frozen cadavers. Before and after the procedure, we assessed the relationships between the tension of the flexor tendons and the flexion angles of the DIP and PIP joints. We compared the maximum DIP and PIP joint angles using the Wilcoxon t test. The distal portion of the FDP was split longitudinally and the ulnar slip was resected from the insertion of the tendon. The remaining radial half of the FDP tendon was passed beneath both slips of the flexor digitorum superficialis tendon, which was then sutured to the radial insertion of the FDP tendon using a mattress stitch. Results: Maximum flexion angles of the DIP joint before and after the procedure were 48° ± 12° and 34° ± 8°, respectively; this difference was statistically significant. Maximum flexion angles of the PIP joint before and after the procedure were 74° ± 14° and 80° ± 9°, respectively; this difference was not statistically significant. Conclusions: The flexion angle of the DIP joint was reduced after undergoing dynamic tenodesis. Biomechanically, dynamic tenodesis for the DIP joint using the remaining FDP tendon is a valuable procedure because it results in a flexion angle greater than 30°. Clinical relevance: The DIP joint can be flexed, and the PIP joint maintains good motion after the procedure. Therefore, FDP dynamic tenodesis on the DIP joint may be a choice in case of an isolated FDP tendon injury.

Objectives: To document the anatomical variation of the lateral femoral cutaneous nerve (LFCN) at the proximal aspect of the thigh and to determine its susceptibility to injury during total hip arthroplasty via a direct anterior approach (DAA).Methods: We obtained 64 thighs from formalin-preserved cadavers of 45 Japanese individuals. LFCN was identified at the level of the inguinal ligament. All nerve branches of the LFCN were carefully traced distally in the subcutaneous tissue. The branching pattern and distribution at the proximal aspect of the thigh were described. A safe zone to avoid LFCN injury in DAA was estimated for the skin incision.Results: The branching pattern of LFCN was highly varied. There were 37% of the anterior type, characterized by a thicker anterior branch, which coursed along the medial border of the tensor fascia lata (TFL) muscle with thinner branches. There were 63% of the posterior type, characterized by posterior branches thicker than or equal to the anterior branch. In 27 of 64 thighs (42%), the LFCN crossed the skin incision along the midline of the TFL muscle.Conclusion: LFCN showed anatomical variation of anterior and posterior branches and 42% were in danger of injury during DAA.

Background: The purpose of this study was to identify the optimal pin insertion point to minimize finger motion restriction for proximal phalangeal fixation in cadaver models. Methods: We used 16 fingers from three fresh-frozen cadavers (age, 82-86 years). Each finger was dissected at the level of the carpometacarpal joint and fixated to a custom-built range of motion (ROM)-measuring apparatus after skin removal. The pin was inserted into the bone through four gliding soft tissues: the interosseous hood, dorsal capsule, lateral band, and sagittal band. Then, each tendon was pulled by a prescribed weight in three finger positions (flexion, extension, and intrinsic plus position). Changes in the metacarpophalangeal (MCP), proximal interphalangeal (PIP), and distal interphalangeal (DIP) angles were measured before and after pinning. We compared the differences between the insertion points using the Tukey-Kramer post hoc test. Results: Placement of pins into the sagittal band significantly restricted MCP joint flexion, while placement into the dorsal capsule and lateral band significantly restricted PIP joint flexion. Only placement into the interosseous hood showed no significant difference in joint angles between the three finger positions compared to pre-pin insertion. There were no significant effects on MCP, PIP, and DIP joint extension. Conclusions: The ROM of the MCP joint was obstructed due to pinning in most areas of insertion. However, pin insertion to the interosseous hood did not obstruct the finger flexion ROM compared to that of other gliding soft tissues; therefore, we believe that the interosseous hood may be a suitable pin insertion point for proximal phalangeal fixation.

Proximal femoral fractures are common in elderly osteoporosis patients; however, its prevalence is clinically rare in hip fracture patients with hip osteoarthritis (OA). This study aimed to evaluate bone strength of the proximal femur with or without hip OA and proximal femoral fracture risk using computed tomography (CT)-based finite element analysis (FEA). A retrospective analysis was done on CT data of 20 patients who underwent total hip arthroplasty for unilateral hip OA. Furthermore, the fracture load between OA and contralateral sides was compared and the association between fracture load and risk factor was analyzed. The fracture load was significantly higher in the OA side than that in the contralateral side (3819.5 ± 1557.8 N vs. 3224.5 ± 943.7 N, respectively; P = 0.0405). There was no significant difference in fracture load between OA and the contralateral side in Kellgren-Lawrence (KL)-3 and KL-4 grade, but the KL-4 fracture load tends to be high (P = 0.2461 and P = 0.0527, respectively). Moreover, there was no significant association between fracture load and OA severity or age. The study findings may assist in predicting bone strength and proximal femur fracture risk. The results of this FEA study indicate the bone strength of the proximal femur was affected by the severity of the osteoarthritis.

Purpose: The triangular fibrocartilage complex (TFCC) serves to stabilize the distal radioulnar joint, but the stress distribution within the TFCC under dynamic loading is unknown. Finite element analysis (FEM) can be used to investigate the stress distribution, but its accuracy depends on knowing the material properties of the TFCC. The aim of this study was to evaluate the material properties of the TFCC using cadaveric specimens. Methods: We obtained 12 upper limbs (6 right and 6 left) from 6 fresh-frozen cadavers (3 women and 3 men). Average age at death was 78.3 years (range, 69-87 years). Using a dorsal approach, we dissected each component of the TFCC. We performed tensile and compressive testing with a mechanical testing machine. Young's modulus was calculated from the slope of the linear part of the stress-strain curve. Results: The Young's modulus was 7.0 ± 2.4 MPa in the volar component, 8.7 ± 2.3 MPa in the ulnar component, 5.4 ± 1.7 MPa in the dorsal component, 6.1 ± 3.3 MPa in the fibers of the fovea, and 8.1 ± 1.2 MPa in the articular disc. Conclusions: The Young's modulus of each component was about 5 to 9 MPa. Specimens used in this study were from elderly individuals, and care must be taken when using these values for FEM. Clinical relevance: These data will be used to perform FEM to predict the mechanical behavior of the ulnar side of the wrist and the stress distribution applied to the TFCC, the distal radioulnar joint, and the ulnar head.

As fractures heal, immature callus formed in the hematoma is calcified by osteoblasts and altered to mature bone. Although the bone strength in the fracture-healing process cannot be objectively measured in clinical settings, bone strength can be predicted by specimen-specific finite element modeling (FEM) of quantitative computed tomography (qCT) scans. FEM predictions of callus strength would enable an objective treatment plan. The present study establishes an equation that converts material properties to bone density and proposes a specimen-specific FEM. In 10 male New Zealand white rabbits, a 10-mm long bone defect was created in the center of the femur and fixed by an external fixator. The callus formed in the defect was extracted after 3-6 weeks, and formed into a (5 × 5 × 5 mm3) cube. The bone density measured by qCT was related to the Young's modulus and the yield stress measured with a mechanical tester. For validation, a 10-mm long bone defect was created in the central femurs of another six New Zealand white rabbits, and fixed by an external fixator. At 3, 4, and 5 weeks, the femur was removed and subjected to Computed tomography (CT) scanning and mechanical testing. A specimen-specific finite element model was created from the CT data. Finally, the bone strength was measured and compared with the experimental value. The bone mineral density σ was significantly and nonlinearly correlated with both the Young's modulus E and the yield stress σ. The material-property conversion equations were E = 0.2391e8.00ρ and ρ = 30.49σ2.41. Moreover, the experimental bone strength was significantly linearly correlated with the prospective FEM. We demonstrated the Young's moduli and yield stresses for different bone densities, enabling a FEM of the bone-healing process. An FEM based on these material properties is expected to yield objective clinical judgment criteria.

BACKGROUND: A1 pulley stretching is recognized as a clinically beneficial treatment for trigger finger. It is thought to lead to an increase in the cross-sectional area of the A1 pulley luminal region, thus improving trigger finger symptoms. The purpose of the present study was thus to evaluate the resultant forces during stretching that increase the CSA of the A1 pulley luminal region using fresh-frozen cadavers. METHODS: Using seven fingers from three fresh-frozen cadavers to replicate A1 pulley stretching, we investigated the resultant forces during stretching that increase the cross-sectional area of the A1 pulley luminal region. The traction forces of the flexor digitorum profundus tendons were increased in steps to 150 N, and the cross-sectional area and height of the A1 pulley luminal region were measured using ultrasonography. FINDINGS: The cross-sectional area of the A1 pulley luminal region increased with step-wise increases in the flexor digitorum profundus traction. On average, the cross-sectional area and height of the A1 pulley luminal region showed increases of 31.4% and 43.6%, respectively, compared to the unloaded condition. INTERPRETATION: These results confirmed that A1 pulley stretching increases the cross-sectional area of the A1 pulley luminal region. A1 pulley stretching has the potential to reduce the severity of trigger finger in patients facing surgery.

We investigated the efficacy of duloxetine on hyperalgesia, histopathological and radiographic findings, pain-related sensory innervation of dorsal-root ganglia (DRG), and spinal changes in a rat model of induced hip osteoarthritis (OA). The right hip joints of male Sprague-Dawley rats (n = 6 rats/group) in the Sham group were injected with 25 μl of sterile saline and 25 μl of sterile saline with 2 mg of monosodium iodoacetate (MIA) were injected to the MIA + Vehicle and MIA + Duloxetine groups. We injected duloxetine 20 mg/kg intraperitoneally in the MIA + Duloxetine group 28 days after injection, whereas rats in the MIA + Vehicle group were injected with 0.5 ml of 20% dimethyl sulfoxide. We assessed hyperalgesia, histopathological changes, immunoreactive (-ir) neurons for calcitonin gene-related peptide and activating transcription factor 3 in DRG, and immunoreactive neurons for ionized-calcium-binding adaptor molecule 1 (Iba1) in the dorsal horn of the spinal cord. MIA administration into the hip joint let to mechanical hyperalgesia of the ipsilateral hind paw (p < 0.05). A single injection of duloxetine significantly attenuated it in induced hip OA (p < 0.05) and suppressed the number of Iba1-ir microglia of the ipsilateral dorsal horn (p < 0.05). These results suggest that a single injection of duloxetine suppressed mechanical hyperalgesia and may influence the expression of Iba1 in the microglia of the ipsilateral dorsal horn in the MIA-induced hip OA. This finding implies the inhibitory effects of duloxetine against neuropathic pain, which may lead to a change of microglial activities. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:422-430, 2020.

BACKGROUND: Femoral nerve palsy is a serious neurological complication following total hip arthroplasty (THA) via a direct anterior approach. One hypothesis is that the nerve injury is caused by malpositioning of retractors over the anterior wall of the acetabulum. The purpose of this cadaveric study was to clarify the anatomical features of the femoral nerve around the anterior acetabular rim and the potential risk of nerve injury during a direct anterior approach to THA. METHODS: We dissected 84 cadaveric hips from 44 formalin-embalmed cadavers. When the cadavers were supine, the iliopsoas muscle and the femoral nerve were exposed and the anterior joint capsule and labrum were resected. The measurement points were determined along the acetabular rim every 30°, and a reference line was drawn from the anterior superior iliac spine to the center of the acetabulum, with the intersection of the rim at 0°. The minimum distance to the femoral nerve margin was measured from 0° to 150° (6 points). Other anatomical structures were measured to determine their association with the distance of the shortest measurement points. RESULTS: The mean minimum distances to the femoral nerve were 33.2 mm at 0°, 24.4 mm at 30°, 18.4 mm at 60°, 16.6 mm at 90°, 17.9 mm at 120°, and 23.2 mm at 150°, showing that the distance at 90° was the shortest (p < 0.001). The thickness of the iliopsoas muscle and the femoral length were positively associated with the distance to the femoral nerve at 90°. CONCLUSIONS: In this cadaveric study, the femoral nerve was within 16.6 to 33.2 mm of the acetabular rim at points from 0° to 150° of a line drawn from the anterior superior iliac spine. The nerve was closest to the rim at 90°, indicating that this is an area of high risk during retractor placement. CLINICAL RELEVANCE: Retractor placement at 90° to the anterior acetabular rim should be avoided to reduce the risk of femoral nerve injury.

Computed tomography-based finite element analysis（CT-FEA）has widely been used for the mechanical analysis of osteoporotic bones. To perform CT-FEA, a conversion equation of the materials is used however, various conversion equations for bone have been reported previously. Therefore, the result depends on which conversion equation is used. New conversion equations must be created because slight variations in the results of the validity verification test using CT-FEA occur, even if various equations are used. This study aimed to identify a more accurate new conversion equation and compare it with past reports. A total of 102 cylindrical cancellous bones（diameter, 10 mm）were collected from nine fresh frozen cadavers. They were thawed at room temperature immediately before the tests were conducted. CT was performed with a calibration phantom, and bone density（g/cm3）was calculated from the obtained Hounsfield unit value using FEA software. The specimens were loaded using a universal testing machine, and yield stress and Young’s modulus were calculated. The correlation between Young’s modulus, yield stress, and bone density obtained from each specimen was investigated, and the bone material property conversion equation was obtained. Previous material property conversion equations were compared with the conversion equation of this study. Young’s modulus and yield stress were correlated with bone density, and the bone material property conversion equation was obtained from the approximate formula. Furthermore, this study’s equation is similar to the Keller vertebra equation. The equation determined in the present study can partly provide a considerable actual bone strength in the CT-FEM calculation compared with the previous studies.

高度な外傷性肘関節骨軟部欠損に対し,肩甲皮弁および人工肘関節置換術を施行し良好な機能改善を認めた症例を経験した.症例は62歳女性.交通事故にて右肘関節開放骨折を受傷した.受傷当日,前医にて洗浄デブリードマン,創外固定術を受けるも肘関節の高度骨軟部組織欠損をきたした.当院搬送後,受傷14日目に初期治療として肩甲皮弁を用いた軟部組織再建を行った.受傷後11ヵ月にて人工肘関節挿入術を行った.受傷後15ヵ月時点で,可動域は他動伸展0°,自動屈曲100°,前腕自動回外90°,回内30°まで改善した.本症例では肩甲皮弁による軟部組織修復を行い感染を来すことなく術後リハビリテーションが可能であった.また高度な骨欠損による上肢の短縮を認めたが,人工肘関節挿入にて短縮を解消し肘の自動屈曲力の改善を得た.肘関節周囲の高度な骨軟部組織欠損に対して肩甲皮弁および人工肘関節を併用した治療選択は時に有用である.(著者抄録)

陳旧性の腱断裂の治療に際しては,多くの場合,Pulvertaft法が用いられる.しかし,術後のリハビリテーションによる伸長の量は渉猟する限りでは報告がない.本研究ではその伸長を検討した.新鮮凍結屍体を使用し,総指伸筋腱,示指伸筋腱,小指伸筋腱を用いてPulvertaft法を行なった.2,3,4,5 weavesで比較・検討を行なった.各検体数は6ずつであった.5-15N,1000cycleで繰り返し牽引試験を行ない,伸長した長さを求めた.その後に破断強度も測定した.2,3,4,5 weaves群における繰り返し牽引負荷後の伸長距離(平均±SD)は,3.48±0.29mm,2.69±0.33mm,2.24±0.17mm,2.52±0.23mmであった.2 weavesでは有意に伸びたが他の各群間に有意差は認めなかった.2,3,4,5 weaves群における破断強度は,それぞれ38.44±3.73N,67.86±6.15N,99.75±14.67N,96.58±10.62Nであった.こちらも2 weavesのみで他と有意差を認めるのみであった.Pulvertaft法を使用した腱縫合では術後のリハビリテーションにより3,4,5 weavesの場合には2〜3mmは伸びる可能性があることが示唆された.術後の緩みを含め,罹患指,利き手・非利き手,筋の短縮の有無などを考慮して手技を行うことで,より良い成績を来すことが期待できる.(著者抄録)

Resistance of de Quervain's disease to conservative treatment has been associated with an intertendinous septum in the first compartment; little is known about the histological features of such a septum. This study aimed to examine the intertendinous septum histologically and note its variations. After dissecting the first extensor compartment of 24 hands from 12 fresh frozen cadavers, the presence of any intertendinous septa was determined. The length of the extensor retinaculum and intertendinous septum was measured; histological findings of the first compartment with or without septa were studied and compared with those of the third/fourth compartment. Intertendinous septa were observed in 12 of 24 wrists. Histological assessment of the intertendinous septum revealed tissue similar in composition to the retinaculum observed between the third and fourth compartments.

Autologous vein wrapping is used to treat recurrent chronic constriction neuropathy and traumatic peripheral nerve injury. However, its use is restricted due to the inability to obtain sufficiently long veins for larger grafts. We previously reported that vein-derived basic fibroblast growth factor (bFGF) promotes heme oxygenase-1 (HO-1), which reduces allodynia via its anti-inflammatory properties. To mimic vein wrapping, we developed a collagen sheet impregnated with bFGF. Chronic constriction injury (CCI) was induced in male Wistar rats as a model of sciatic nerve injury, and the rats were divided into three groups: (i) untreated after CCI surgery (control group), (ii) treated with a collagen sheet wrap impregnated with phosphate-buffered saline (PBS/CS group), and (iii) treated with a collagen sheet wrap impregnated with bFGF (bFGF/CS group). Pain behavior (von Frey test) was evaluated on postoperative days (PODs) 1, 5, 7, and 14. Quantitative polymerase chain reaction was conducted on sciatic nerve RNA to quantify HO-1 gene, Hmox1, expression. Enzyme-linked immunosorbent assay were used to determine HO-1 protein levels on POD 1. von Frey testing showed significantly greater pain hypersensitivity in the control and PBS/CS groups than the bFGF/CS group. In the bFGF/CS group, Hmox1 messenger RNA and HO-1 protein levels were significantly increased in the sciatic nerve compared with the control and PBS/CS groups on PODs 1 and 5 and POD 1, respectively. The bFGF/CS group showed decreased allodynia and HO-1 induction, as observed with vein wrapping. Therefore, local application of bFGF may be an alternative treatment strategy for compressive neuropathy and peripheral nerve trauma in clinical settings. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2258-2263, 2019.

Objective: The aim was to compare the fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of the sciatic and femoral nerves in patients with unilateral osteoarthritis of the hip (OA) and osteonecrosis of the femoral head (ONFH) using diffusion tensor imaging (DTI) and to investigate the mechanism of hip pain. Methods: Forty-four patients (22 OA and 22 ONFH) underwent DTI of the sciatic and femoral nerves at the level of the hip joint and the S1 roots to visualize the tractography and quantify the FA and ADC values. Results: The tractography of the femoral and the sciatic nerves on the affected side with OA and ONFH were similar to those on the normal side. The mean FA values of the sciatic and femoral nerves, and the S1 roots were 0.542, 0.551, and 0.316 with OA, 0.568, 0.560, and 0.318 with ONFH on the affected side, and 0.559, 0.560, and 0.315 on the normal side, respectively, and did not show significant differences. The FA values of the sciatic nerve on the affected side with OA decreased with longer pain duration. Conclusion: The FA and ADC values of the sciatic and femoral nerves in patients with unilateral OA and ONFH showed no significant differences between the affected and normal sides.

The aim of this study was to investigate the local production of proinflammatory cytokines, pain-related sensory innervation of dorsal-root ganglia (DRG), and spinal changes in a rat model of induced hip osteoarthritis (OA). Seventy-five Sprague-Dawley rats were used, including 25 controls and 50 injected into the right hip joints (sham group, injected with 25 µl of sterile saline: N = 25; and monosodium iodoacetate (MIA) group, injected with 25 µl of sterile saline with 2 mg of MIA: N = 25). We measured the local production of TNF-α, immunoreactive (-ir) neurons for calcitonin gene-related peptide (CGRP), and growth associated protein-43 (GAP-43) in DRG, and immunoreactive neurons for ionized-calcium-binding adaptor molecule-1 (Iba-1) in the dorsal horn of spinal cord, on post-induction days 7, 14, 28, 42, and 56 (N = 5 rats/group/time point). For post-induction days 7-42, the MIA group presented significantly elevated concentrations of TNF-α than the other groups (p < 0.01), and a higher expression of CGRP-ir in FG-labeled DRG neurons than the sham group (p < 0.01). MIA rats also presented significantly more FG-labeled GAP-43-ir DRG neurons than the sham group on post-induction days 28, 42, and 56 (p < 0.05), and a significantly higher number of Iba-1-ir microglia in the ipsilateral dorsal horn than the other groups, on post-induction days 28, 42, and 56. The results suggest that in rat models, pain-related pathologies due to MIA-induced hip OA, originate from inflammation caused by cytokines, which leads to progressive, chronic neuronal damage that may cause neuropathic pain. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2978-2986, 2018.

INTRODUCTION: An abnormal distal insertion of the extensor pollicis brevis (EPB) tendon into the thumb interphalangeal joint (IP) has been observed in refractory cases of de Quervain's disease. This is associated with the extensor being wider at the midpoint of the proximal phalanx; however, there is no method to noninvasively measure this. This study evaluated the accuracy of measuring the extensor width using ultrasonography, to establish a noninvasive method for predicting an EPB extending the IP insertion. MATERIALS AND METHODS: Of 23 arms from 12 fresh frozen cadavers, the extensor tendon width at the midpoint of the proximal phalanx was measured using ultrasonography and directly at dissection. The association between these values was evaluated using correlation analysis. A cut-off value of extensor tendon width was obtained using receiver operating characteristic analysis. RESULTS: A strong correlation was observed between the ultrasonography and the measured values. The EPB tendons were normal in 13 arms (57%) and extended in 10 (43%), with a significant difference between these groups in the mean width of the extensor tendon (6.8 ± 1.1 vs. 8.4 ± 1.0 mm). A cut-off extensor tendon width of 8.0 mm yielded an EPB extending the IP. CONCLUSION: An EPB extending the IP tendon can be predicted by measuring the extensor tendon width at the midpoint of the proximal phalanx using ultrasonography. The cut-off tendon width value of ≥ 8.0 mm may be useful for assessments prior to surgery and for conservative care.

BACKGROUND: This study aimed to investigate whether the distance between the radial nerve and rotational center of the elbow joint when observing from the lateral surface of the humerus changes according to passive elbow joint flexion for safe external fixation with a hinged fixator of the elbow joint. METHODS: Twenty fresh-frozen cadaveric arms were dissected. The points where the radial nerve crosses over the posterior aspect of the humerus, crosses through the lateral center, and crosses over the anterior aspect of the humerus were defined in the lateral view of the elbow joint, using fluoroscopy, as R1, R2, and R3, respectively. The distances between the rotational center and each point on the radial nerve were measured when the flexion angle of the elbow joint was 10°, 50°, 90°, and 130°. RESULTS: The distances between the rotational center and R1, R2, and R3 were 118 mm, 94 mm, and 65 mm, respectively, when the flexion angle was 10°; 112 mm, 93 mm, and 74 mm, respectively, for 50°; 108 mm, 93 mm, and 77 mm, respectively, for 90°; and 103 mm, 94 mm, and 83 mm, respectively, for 130°. The distance between the rotational center and R2 was constant regardless of the flexion angle. With elbow joint extension, the distances between R1 and R3 increased; the safe zone, a region where the radial nerve would not be located on the humerus, was the smallest in extension. When the elbow joint was flexed, the distances between R1 and R3 decreased; the safe zone was the largest in flexion. CONCLUSIONS: This study showed that the radial nerve location on the humerus varied based on the flexion angle of the elbow joint; the safe zone may change. A half-pin can be likely inserted safely, avoiding the elbow joint extension position.

BACKGROUND: The purpose of this study was to validate a diaphyseal femoral fracture model using a finite element analysis (FEA) with mechanical testing in fresh-frozen cadavers. METHODS: We used 18 intact femora (9 right and 9 left) from 9 fresh-frozen cadavers. Specimens were obtained from 5 males and 4 females with a mean age of 85.6 years. We compared a computed tomography (CT)-based FEA model to diaphyseal femoral fracture loads and stiffness obtained by three-point bending. Four material characteristic conversion equations (the Keyak, Carter, and Keller equations plus Keller's equation for the vertebra) with different shell thicknesses (0.3, 0.4, and 0.5 mm) were compared with the mechanical testing. RESULTS: The average fracture load was 4582.8 N and the mean stiffness was 942.0 N/mm from actual mechanical testing. FEA prediction using Keller's equation for the vertebra with a 0.4-mm shell thickness showed the best correlations with the fracture load (R2 = 0.76) and stiffness (R2 = 0.54). Shell thicknesses of 0.3 and 0.5 mm in Keller's equation for the vertebra also showed a strong correlation with fracture load (R2 = 0.66 for both) and stiffness (R2 = 0.50 and 0.52, respectively). There were no significant correlations with the other equations. CONCLUSION: We validated femoral diaphyseal fracture loads and stiffness using an FEA in a cadaveric study.

Background: The K-line, which is a virtual line between the midpoints of the antero-posterior canal diameter at C2 and C7, can be useful for determination of surgical procedures for cervical ossification of the posterior longitudinal ligament (OPLL). Although K-line is originally measured with plain radiogram, computed tomography multiplanar reconstruction (CT-MPR) is applied for K-line measurement by several surgeons. The purpose of the present study was to analyze whether there is a difference in K-lines obtained from radiographs of standing patients and those obtained from CT-MPR images of supine patients. Methods: The present study included 65 patients with cervical OPLL underwent surgical treatment. We investigated the K-line (+ or -) before surgery, measured from lateral cervical spine radiographs taken in standing patients in a neutral position (X-P-based K-line) and CT-MPR mid-sagittal images obtained in supine patients (CT-based K-line). The X-P-based and CT-based K-lines were compared and differences between them were assessed. Results: The-X-P-based K-line was found to be (+) in 35 patients and (-) in 30 patients. Four of 35 patients with an X-P-based K-line (11%) showed a change from K-line (+) to (-) in CT-based K-line measurements. One of 30 patients with an X-P-based K-line (3%) showed a change from (-) to (+) in CT-based measurements. Conclusions: The K-line should be measured with plain radiogram of standing patients because X-P-based K-line and CT-based K-line can be different.

INTRODUCTION: According to the anatomical literature, the extensor pollicis brevis (EPB) tendon passes through the first compartment and enters the base of the proximal phalanx of the thumb. There have been a few reports on the different types of supernumerary EPB tendons; however, an unusual course of the EPB tendon is extremely rare. MATERIALS AND METHODS: During routine cadaveric dissection in the Department of Gross Anatomy, we detected an variant EPB muscle in a 96-year-old fresh female cadaver. RESULTS: The EPB muscle originated from the posterior surface of the radius and interosseous membrane. However, the EPB tendon passed through the third compartment instead of the first compartment. It ran parallel to the extensor pollicis longus (EPL) tendon and entered the base of the thumb proximal phalanx. The EPL tendon was attached to the base of the first distal phalanx, as normally observed. Both EPB and EPL muscles were innervated by the posterior interosseous nerve. CONCLUSIONS: We report a case of a variant course of the EPB tendon appearing in the third extensor compartment of the wrist with the EPL tendon. The knowledge of this anatomic variation will be helpful for accurate diagnosis and surgical planning.

The clinical efficacy of autologous vein wrapping for recurrent compressive neuropathy has been demonstrated however, the underlying mechanisms of this technique remain unclear. Rats were divided into chronic constriction injury (CCI) and CCI + vein wrapping (CCI + VW) groups. Mechanical allodynia was evaluated using von Frey filaments. To identify the neuroprotective factors released from veins, basic fibroblast growth factor (bFGF) mRNA expression in veins was compared to that in the sciatic nerve. The response of heme oxygenase-1 (HO-1) expression to vein wrapping was evaluated by RT-PCR and enzyme-linked immunosorbent assays. The effects of exogenous bFGF on HO-1 expression were evaluated using a sciatic nerve cell culture. Vein wrapping significantly increased the withdraw threshold levels compared to the untreated CCI group. bFGF mRNA expression in veins was higher than that in untreated sciatic nerves. HO-1 mRNA expression was induced at higher levels in sciatic nerve cells in the presence of exogenous bFGF compared to untreated control cells. HO-1 mRNA and protein expression in the sciatic nerve were also higher in the CCI + VW group compared with the CCI group. Our results suggest that vein-derived bFGF contributes to the therapeutic benefit of vein wrapping through the induction of HO-1 in the sciatic nerve. Vein wrapping is a useful technique for reducing neuropathic pain. Further understanding of the neurotrophic factors released from veins may help to optimize current procedures for treating recurrent compressive neuropathy and traumatic peripheral nerve injury, and lead to the development of new therapeutic methods using recombinant neurotrophic factors. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:898–905, 2018.

Although the therapeutic potential of vein wrapping (VW) for recurrent compressive neuropathy has been widely reported, the mechanisms underlying this technique have not been characterized. M2 macrophages induced by interleukin-4 (IL-4) or interleukin-10 (IL-10) have an anti-inflammatory function and play an important role in peripheral nerve repair. To evaluate whether VW promotes M2 polarization, we divided chronic constriction injury (CCI) rats into untreated and VW (CCI + VW)-treated groups. Pain withdrawal thresholds in both groups were evaluated using von Frey filaments. Expression of the anti-inflammatory cytokines IL-4 and IL-10 in vein and nerve were quantified using real time polymerase chain reaction (RT-PCR), and expression of the anti-inflammatory M2 macrophage markers CD206 and arginase-1 (Arg1) after VW was assessed by RT-PCR and immunohistochemistry. To evaluate the effect of exogenous IL-4 or IL-10 on M2 macrophage-marker expression, CD11b-positive macrophages isolated from sciatic nerve were stimulated with recombinant IL-4 and IL-10. VW significantly increased the pain withdrawal threshold. IL-4 and IL-10 mRNA expression was higher in veins than in the sciatic nerve. VW significantly increased CD206 and Arg1 mRNA expression compared to the CCI group. The number of CD206- and Arg1-immunoreactive cells in nerve bundles was twofold higher in the CCI + VW than CCI group. Application of exogenous IL-4 doubled CD206 and Arg1 mRNA expression in CD11b-positive macrophages. These results show that vein-derived IL-4 potentiates the benefit of VW through the activation of M2 macrophages in the sciatic nerve. Our results may help to optimize current procedures for treating recurrent compressive neuropathy. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Background: The purpose of this cadaveric study was to clarify the proximal limit for the subvastus approach (SVA) in total knee arthroplasty to decrease potential vascular injury. Methods: Seventy embalmed knees underwent a modified SVA using a 14-cm oblique medial incision. Anatomical features of the descending genicular artery (DGA) were investigated with regard to variation, distance of the vessels from surgical landmarks, and sex differences. Results: The DGA was identified in 62 knees (89%), while it was absent in 8 knees (11%) in the latter, the articular, saphenous, and muscular branches arose separately from the femoral artery. The mean distances from the tibial tuberosity and medial joint line to the origin of the DGA were 15.5 ± 1.6 cm and 12.6 ± 1.6 cm, respectively. Both distances were significantly longer in males than in females (P &lt .01, respectively). A strong positive correlation was found between the distance from the tibial tuberosity to the origin of the DGA and the distance from the medial joint line to the origin of the DGA (Spearman's correlation coefficient, R2 = 0.72, P &lt .01). A weak positive correlation was found between the distance from the tibial tuberosity to the origin of the DGA and lower leg length (R2 = 0.13, P &lt .01). No vascular injuries were observed in this surgical exposure. Conclusion: The DGA showed several variations and was absent 11% of the time. An oblique medial incision within 14 cm from the tibial tuberosity followed by arthrotomy is considered a safe zone for the SVA.

Previously, a rat model of chronic compressive myelopathy that uses a water-absorbing polymer inserted under a spinal lamina was reported. However, the best size and coefficient of expansion of the polymer sheet have not yet been established. The aim of the present study was to optimize these properties in an ideal rat model of cervical compressive myelopathy. Thirty rats were used in this study. A sheet of water-absorbing polymer was inserted under the cervical laminae. Rats were divided randomly into five experimental groups by the expansion rate (350 or 200%) and thickness (0.5 or 0.7 mm) and the control. After the surgery, the severity of paralysis was evaluated for 12 weeks. At 12 weeks after the surgery, cresyl violet staining was performed to assess the number of motor neurons in the anterior horn at the C4/C5 segment and Luxol Fast Blue staining was performed to assess demyelination in the corticospinal tract at the C7 segment. 'Slow-progressive' paralysis appeared at 4-8 weeks postoperatively in rat models using sheets with 200% expansion. By contrast, only temporary paralysis was observed in rat models using sheets with 350% expansion. A loss of motor neurons in the anterior horn was observed in all groups, except for the control. Demyelination in the corticospinal tract was observed in rat models using sheets with 200% expansion, but not rat models using sheets with 350% expansion. A polymer sheet that expands its volume by 200% is an ideal material for rat models of cervical compressive myelopathy.

Background: Finite element analysis (FEA) of the proximal femur has been previously validated with large mesh size, but these were insufficient to simulate the model with small implants in recent studies. This study aimed to validate the proximal femoral computed tomography (CT)-based specimen-specific FEA model with smaller mesh size using fresh frozen cadavers. Methods: Twenty proximal femora from 10 cadavers (mean age, 87.1 years) were examined. CT was performed on all specimens with a calibration phantom. Nonlinear FEA prediction with stance configuration was performed using Mechanical Finder (mesh, 1.5 mm tetrahedral elements; shell thickness, 0.2 mm; Poisson's coefficient, 0.3), in comparison with mechanical testing. Force was applied at a fixed vertical displacement rate, and the magnitude of the applied load and displacement were continuously recorded. The fracture load and stiffness were calculated from force-displacement curve, and the correlation between mechanical testing and FEA prediction was examined. Results: A pilot study with one femur revealed that the equations proposed by Keller for vertebra were the most reproducible for calculating Young's modulus and the yield stress of elements of the proximal femur. There was a good linear correlation between fracture loads of mechanical testing and FEA prediction (R-2 = 0.6187) and between the stiffness of mechanical testing and FEA prediction (R-2 = 0.5499). There was a good linear correlation between fracture load and stiffness (R-2 = 0.6345) in mechanical testing and an excellent correlation between these (R-2 = 0.9240) in FEA prediction. Conclusions: CT-based specimen-specific FEA model of the proximal femur with small element size was validated using fresh frozen cadavers. The equations proposed by Keller for vertebra were found to be the most reproducible for the proximal femur in elderly people.

Background: The aim was to clarify the normal fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of the sciatic and femoral nerves at the level of the hip joint and to visualize the neural tracts with diffusion tensor imaging (DTI). Methods: Twenty-four healthy volunteers (12 men and 12 women, age 20-29 years) underwent DTI for visualization with tractography and quantification of FA and ADC values on a 3 Tesla MRI (b value =800 s/mm2, motion probing gradient, 11 directions, time to repeat/echo time =9000/72.6 ms, axial slice orientation, slice thickness =3.0 mm with no inter-slice gap, field of view =320 x 320 mm, 96 x 192 matrix, 75 slices, number of acquisitions =4). Regions of interest in the sciatic nerve were defined at the femoral head, the S1 root, and the midpoint levels. The femoral nerve was evaluated at 3-4 cm proximal to the femoral head level. Results: The tractography of the sciatic and femoral nerves were visualized in all participants. The mean FA values of the sciatic nerve were increased distally from the S1 root level, through the midpoint, and to the femoral head level (0.314, 0.446, 0.567, p =0.001, respectively). The mean FA values of the femoral nerve were 0.565. The mean ADC values of the sciatic nerves were significantly lower in the S1 root level than in the midpoint and the femoral head level (1.481, 1.602, 1.591 x 10(-3) x 10(-3) mm(2)/s, p =0.001, respectively). The ADC values of the femoral nerve were 1.439 x 10(-3) mm(2)/s. FA and ADC values showed moderate to substantial inter-and intra-observer reliability without significant differences in gender or laterality. Conclusion: Visualization and quantification of the sciatic and femoral nerves simultaneously around the hip joint were achieved in healthy young volunteers with DTI. Clinical application of DTI is expected to contribute to hip pain research.

Orthopedic trauma surgeons often encounter Smith's fracture in patients who report that they have fallen on the palms of their hands. The aim of this study was to clarify the pathogenesis of Smith's fracture in basic clinical aspects. First, a survey was conducted for investigating the mechanism of injury and arm position at the time of injury among patients with Smith's fractures who consulted at our outpatient clinic. Second, we created three-dimensional finite element models (FEMs) to predict the influence of arm position on the type of injury resulting from a fall. These predictions were then used in ten freshly frozen cadavers to provide experimental proof of Smith's fractures resulting from the impact on the palmar side. Twenty-six patients (5 males and 21 females) with Smith's fractures were enrolled in this study. Injury resulting from a fall on the palm of the hand, the dorsum, or ulno-dorsum of the hand, and fisting handle was observed in 16 cases (61%), 3 cases (12%), and 1 case (4%), respectively. Six patients were uncertain of their arm position at the time of injury. FEM analysis showed that Smith's fractures occurred when the angle between the long axis of the forearm and the ground was 30°–45° in the sagittal plane and 75°–90° in the coronal plane. Smith's fractures occurred in 7 of 10 wrists in the experimental study, whereas no Colles’ fractures were observed. This study demonstrated that Smith's fracture results from falling on the palm of the hand. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2435–2441, 2017.

Introduction: The extensor pollicis brevis (EPB) tendon normally inserts into the base of the proximal phalanx of the thumb. However, a distal insertion of the EPB tendon into the thumb interphalangeal joint has been reported in refractory cases of de Quervain’s disease. We hypothesized that the EPB tendon is wider beyond the thumb metacarpophalangeal joint in patients with extended EPB. This study aimed to evaluate the relationship between the extensor tendon width and the point of distal insertion of the EPB tendon. Materials and methods: In 45 hands from 18 male and 27 female adult cadavers, the first extensor compartment was dissected and the existence of the intertendinous septum was assessed. The extensor tendon width was measured at the midpoint of the proximal phalanx, and relationships between extended EPB tendon, existence rate of the intertendinous septum, sex, and extensor tendon width were examined. Results: Of 45 cases, intertendinous septum and extended EPB tendon were observed in 37 (82.2%) and 23 (51.1%), respectively. There was no significant difference between the existence rates of both these factors and sex. The mean extensor tendon width in the extended EPB group was significantly greater than in the normal EPB group. The cut-off value of extensor tendon width in the extended EPB group was 7.12 mm. Conclusions: The extensor tendon width was wider in the extended EPB group than in the normal EPB group, suggesting that the differences in the EPB tendon width can be used to identify various anatomical variations in extended EPB.

【目的】教科書的には手背をついて転倒することでSmith骨折が発生すると記載されている。本研究の目的は手掌接地で発症するSmith骨折の機序を、基礎的側面から明らかにすることである。【方法】手掌接地でSmith骨折を生じ得る接地角度を推察するために、CT-DICOM Dataを用いた有限要素解析による先行研究を行った。次に、新鮮凍結屍体を用いて、先行研究の結果から得られた接地角度で手掌接地の衝突試験を実施し、CTと解剖によって骨折型を記録した。【結果】有限要素解析でSmith骨折を生じ得る接地角度域は前腕の地面に対する接地角度が矢状面で30〜45°、冠状面で90〜105°であった。よって矢状面30°、冠状面90°で衝突試験を行った。橈骨遠位端骨折は10手中7手に発生し、全例がSmith骨折でColles骨折をきたした検体は無かった。【結語】浅い角度で接地すれば手掌接地の転倒でもSmith骨折を生じる可能性がある。(著者抄録)

【目的】本研究の目的は大腿骨頭壊死症に対する体外衝撃波療法(ESWT)の安全性と有効性を評価することである。【方法】第1相臨床試験として前向き症例対照研究を行った。選択基準は壊死範囲が広く、骨頭圧潰が進行していることである。ESWTは骨頭の前方から後方に向かって5,000発を照射した。エネルギー流束密度はレベル1(0.03mJ/mm2)からレベル7(0.36mJ/mm2)までとした。ヒストリカルコホートを対照群としてESWT群にマッチさせた。【結果】ESWT群と対照群はそれぞれ28股関節であった。壊死の進行や神経血管障害など明らかな合併症は認めなかった。ESWT群は股関節点数と疼痛点数が徐々に改善し、治療の最終時点で対照群に対して有意差を認めた(それぞれp=0.034と0.019)。2年後の人工関節への移行をエンドポイントにした場合の生存率はESWT群と対照群で有意差を認めなかった(35.1%対24.7%、p=0.749)。しかしながら、Cox回帰分析により、type C2はtype C1に対して8.6倍人工関節へ移行しやすいことが示された(p=0.004)。【結論】大腿骨頭壊死症に対するESWTの安全性と有効性が示唆された。(著者抄録)

OBJECTIVE Fusion surgery with instrumentation is a widely accepted treatment for cervical spine pathologies. The authors propose a novel technique for subaxial cervical fusion surgery using paravertebral foramen screws (PVFS). The authors consider that PVFS have equal or greater biomechanical strength than lateral mass screws (LMS). The authors' goals of this study were to conduct a biomechanical study of PVFS, to investigate the suitability of PVFS as salvage fxation for failed LMS, and to describe this novel technique. METHODS The authors harvested 24 human cervical spine vertebrae (C3-6) from 6 fresh-frozen cadaver specimens from donors whose mean age was 84.3 ± 10.4 years at death. For each vertebra, one side was chosen randomly for PVFS and the other for LMS. For PVFS, a 3.2-mm drill with a stopper was advanced under lateral fluoroscopic imaging. The drill stopper was set to 12 mm, which was considered suffciently short not to breach the transverse foramen. The drill was directed from 20° to 25° medially so that the screw could purchase the relatively hard cancellous bone around the entry zone of the pedicle. The hole was tapped and a 4.5-mm-diameter × 12-mm screw was inserted. For LMS, 3.5-mm-diameter × 14-mm screws were inserted into the lateral mass of C3-6. The pullout strength of each screw was measured. After pullout testing of LMS, a drill was inserted into the screw hole and the superior cortex of the lateral mass was pried to cause a fracture through the screw hole, simulating intraoperative fracture of the lateral mass. After the procedure, PVFS for salvage (sPVFS) were inserted on the same side and pullout strength was measured. RESULTS The CT scans obtained after screw insertion revealed no sign of pedicle breaching, violation of the transverse foramen, or fracture of the lateral mass. A total of 69 screws were tested (23 PVFS, 23 LMS, and 23 sPVFS). One vertebra was not used because of a fracture that occurred while the specimen was prepared. The mean bone mineral density of the specimens was 0.29 ± 0.10 g/cm3. The mean pullout strength was 234 ± 114 N for PVFS, 158 ± 91 N for LMS, and 195 ± 125 N for sPVFS. The pullout strength for PVFS tended to be greater than that for LMS. However, the difference was not quite signifcant (p = 0.06). CONCLUSIONS The authors introduce a novel fxation technique for the subaxial cervical spine. This study suggests that PVFS tend to provide stronger fxation than LMS for initial applications and fxation equal to LMS for salvage applications. If placement of LMS fails, PVFS can serve as a salvage fxation technique.

解剖学は、ヒトの病状変化や疾患の有無を診る看護師などさまざまな医療専門職の教育で必要とされる基礎科目である。加えて、生物学と共に医療にとって不可欠な基礎科目であり、上記の専門職のための国家試験にも出題される。しかし、人体の基本構造を知るという点で非常に近い高校の生物学の知識の定着が十分でない学生もいる上、生物学を履修せずに物理・化学で受験した学生もおり、その知識には学生間で大きな隔たりがある。筆頭著者は看護師養成大学において、解剖学・生物学の講義を担当してきた。その経験からガニェ9教授事象を参考にして、入学者のレディネスに合わせ、看護師養成大学の実情に合ったカリキュラムと授業を取り入れた。さらに、毎回小テストを行い、補習や個別指導を実施することにより、専門科目に対応できる学力を定着させることが出来た。解剖学の学期末の期末試験の成績では全体平均点87.3(SD11.0、中央値81.0)と高得点であった。ここでは筆者らの解剖学での取り組みを中心に紹介する。(著者抄録)

PURPOSE: Forearm diaphysis fractures are usually managed by open reduction internal fixation. Recently, locking plates have been used for treatment. In the long-term period after surgery, some patients present with bone atrophy adjacent to the plate. However, a comparison of locking and conventional plates as a cause of atrophy has not been reported. The aim of this study was to investigate long-term bone atrophy associated with use of locking and conventional plates for forearm fracture treatment. METHODS: In this study we included 15 patients with forearm fracture managed by either locking or conventional plates and with more than 5 years of follow-up. Computed tomographic imaging of both forearms was performed to assess bone thickness and local bone mineral density and to predict bone strength without plate reinforcement based on finite element analysis. RESULTS: Mean patient age at surgery was 48.0 years. Eight patients underwent reduction with fixed locking plates and were followed up for a mean of 79.5 months; the remaining 7 patients were treated with conventional plates and were followed up for a mean of 105.0 months. Compared with the conventional plate group, the locking plate group had the same fractured limb-contralateral limb ratio of cortex bone thickness, but had significantly lower ratios of mineral density adjacent to the plate and adjusted bone strength. CONCLUSIONS: This study demonstrated bone atrophy after locking plate fixation for forearm fractures. Treatment plans for forearm fracture should take into consideration the impact of bone atrophy long after plate fixation. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

The principal aim of this study was to clarify the time course of pain-related behavior and pain-related sensory innervation in a rat model of hip osteoarthritis (OA) induced by intra-articular injection of mono-iodoacetate (MIA). Using 6-week-old male Sprague Dawley rats, 25l of sterile saline of 1% Fluoro-Gold solution (FG) (control group; n=30) and 25l of sterile saline of 1% FG with 2mg of MIA (MIA group; n=30) was injected into the right hip joints. Gait function was evaluated using a CatWalk system after 7, 14, 28, 42, and 56 days (n=5, respectively). Neurons in the dorsal root ganglion (DRG) between L1 and L5 were immunostained for calcitonin gene-related peptide (CGRP) and activating transcription factor-3 (ATF3). Gait analysis revealed the mean six parameters of hind paws at all time points were significantly lower in the MIA group (p=0.05). The number of CGRP-immunoreactive (-IR) DRG neurons was significantly increased on days 7, 14, 28, and 42 peaking at 14 days in the MIA group. By contrast, expression of ATF3-IR in FG-labeled DRG neurons was significantly increased on days 42 and 57. The FG-labeled DRG neurons were distributed between L1 and L5, mainly at the L4 level. Pain-related behavior indicated by gait disturbance was observed in a MIA model of hip OA in rat. Early elevation of CGRP expression and late expression of ATF-3 were demonstrated in DRG neurons, possibly reflecting inflammatory pain and neuropathic pain in hip OA. (c) 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1424-1430, 2017.

The principal aim of this study was to clarify the time course of pain-related behavior and pain-related sensory innervation in a rat model of hip osteoarthritis (OA) induced by intra-articular injection of mono-iodoacetate (MIA). Using 6-week-old male Sprague Dawley rats, 25 μl of sterile saline of 1% Fluoro-Gold solution (FG) (control group n = 30) and 25 μl of sterile saline of 1% FG with 2 mg of MIA (MIA group n = 30) was injected into the right hip joints. Gait function was evaluated using a CatWalk system after 7, 14, 28, 42, and 56 days (n = 5, respectively). Neurons in the dorsal root ganglion (DRG) between L1 and L5 were immunostained for calcitonin gene-related peptide (CGRP) and activating transcription factor-3 (ATF3). Gait analysis revealed the mean six parameters of hind paws at all time points were significantly lower in the MIA group (p = 0.05). The number of CGRP-immunoreactive (-IR) DRG neurons was significantly increased on days 7, 14, 28, and 42 peaking at 14 days in the MIA group. By contrast, expression of ATF3-IR in FG-labeled DRG neurons was significantly increased on days 42 and 57. The FG-labeled DRG neurons were distributed between L1 and L5, mainly at the L4 level. Pain-related behavior indicated by gait disturbance was observed in a MIA model of hip OA in rat. Early elevation of CGRP expression and late expression of ATF-3 were demonstrated in DRG neurons, possibly reflecting inflammatory pain and neuropathic pain in hip OA. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1424–1430, 2017.

【目的】日本は近年,世界でも有数の高齢化社会が進んでおり,大腿骨近位部骨折は増加傾向にある。今回の目的は超高齢者(95歳以上)の大腿骨近位部骨折後の歩行能力や生命予後についてついて検討することである。【方法】2008年10月から2013年9月に当科にて治療を行った95歳以上の大腿骨近位部骨折症例を対象とした。手術を行った手術治療群31例(男性5例 女性26例 平均年齢96.5歳)は歩行能力獲得に関連する因子と生命予後について検討し,保存治療群13例(男性1例 女性12例 平均年齢96.3歳)に対しては生命予後の検討を行った。【結果】手術治療群では術前に歩行機能が残存していた28例中12例(43%)が歩行能力を再獲得できた。術前の歩行能力が高い群では歩行再獲得率が有意に高く,認知症があると歩行再獲得率が低い傾向であったが有意ではなかった。術後1年の生存率は歩行再獲得できた群は100%,歩行不能となった群は51%と有意差があった。手術治療群の1年生存率は70%であり,保存治療群の38%より有意に高かった。【考察】超高齢者の大腿骨近位部骨折であっても手術を行い,術前の歩行能力が高かった群では諸家の報告と比較しても,良好な予後となった。手術適応は年齢だけでなく,術前のADLを考慮して決定するべきであると考えられた。(著者抄録)

Objective: To determine the distribution of referred hip pain in patients with idiopathic osteonecrosis of the femoral head (ION). Methods: We prospectively documented 119 hips in 90 patients with ION (mean age 51 years). Patients identified the location of pain originating in their hip on a drawing of the body. Osteoarthritis of the hip (OA) was used as a historical cohort. Results: Referral of pain originating from the hip in patients with ION was 93% (111 hips) to the groin, 68% (81 hips) to the knee, 36% (43 hips) to the anterior thigh, 34% (40 hips) to the buttock, 18% (22 hips) to the lower leg, 9% (11 hips) to the greater trochanter, and 8% (9 hips) to the low back. About 97% (115 hips) of pain was located in the hip region (groin, buttock, and greater trochanter) and 77% (92 hips) showed referred pain (anterior thigh, knee, lower leg, and low back). Pain from ION was significantly more frequent in the knee and lower leg, but significantly less frequent in the lower back than pain from OA. Conclusion: We should be aware of ION masquerading as pain in the knee or anterior thigh.