Influence of Gradual Elongation to the Patella Tendon Insertion in Rabbits

The purpose of this study was to examine the histological changes at the patella tendon (PT) insertion site under gradual elongation in rabbits. Gradual elongation of the PT was performed using external fixation for 4 weeks, with a lengthening speed of 0.5 mm/day (elongation group; n = 24). Rabbits in the sham group underwent the same surgical procedure without gradual elongation (sham group; n = 24). Eight animals were sacrificed 1, 2 and 4 weeks after surgery in each group, respectively. Average thicknesses of stained glycosaminoglycan (GAGs) areas by Safranin-O staining in the total cartilage layer and the uncalcified fibrocartilage layer in the elongation group were significantly higher than that in the sham group at 4 weeks (p < 0.05) and that in the intact PT group (n = 6, p < 0.05). In the elongation group, the peak in the average thicknesses of the stained GAGs areas in the total cartilage layer and the uncalcified fibrocartilage layer were observed at 4 weeks. Gradual elongation of PT insertion significantly affected the increase in the average thicknesses of the stained GAGs areas in the cartilage layer especially in the uncalcified fibrocartilage layer at 4 weeks in rabbits. Clinically, insertions of tendon and ligament can extend during gradual elongation using external fixation more than 4 weeks after the operation

Cefazolin-containing poly(ε-caprolactone) sponge pad to reduce pin tract infection rate in rabbits

AbstractIn our previous study, a fibroblast growth factor-2 (FGF-2)–apatite composite layer coated on titanium screws effectively prevented pin tract infection in rabbits because of enhanced wound healing; however, the FGF-2–apatite composite layers did not completely prevent pin tract infection. Thus, we recently developed a poly(ε-caprolactone) (PCL) sponge pad embedded with cefazolin sodium (+CEZ), which has a fast-acting bactericidal effect. The pad is placed on the skin around the screws. The purpose of this study was to determine the anti-infective efficacy of the +CEZ pad on the pin–skin interface of the FGF-2–apatite-coated titanium screws. The +CEZ pads were prepared by mixing PCL and CEZ in 1,4-dioxane, followed by freeze-drying and compaction. They were analyzed regarding their surface structure, in vitro CEZ release profile, and bactericidal activity. The FGF-2–apatite-coated screws were implanted percutaneously in bilateral rabbit proximal tibial metaphyses—with and without the +CEZ pad—for 4 weeks (n = 20). The + CEZ pads consisted of a porous matrix of PCL in which CEZ was embedded. The CEZ-release profile showed an initial burst on Day 1 and a sustained release lasting for 30 days. The +CEZ pad retained its bactericidal activity against Staphylococcus aureus after preincubation on an agar plate for 7 days. Based on visual inspection, the pin tract infection rate was successfully reduced from 72.2% to 15.0% with the +CEZ pad (p < 0.05), which reduced the bacterial count, especially S. aureus (p < 0.05). The histological inflammation rate of the soft tissues was also significantly lower with the +CEZ pad than without it (p < 0.05). The pin tract infection rate was reduced to one-fifth with the +CEZ pad. Using it as described improves infection resistance during percutaneous implantation

Training with Hybrid Assistive Limb for walking function after total knee arthroplasty

BackgroundThe Hybrid Assistive Limb (HAL, CYBERDYNE) is a wearable robot that provides assistance to patients while walking, standing, and performing leg movements based on the intended movement of the wearer. We aimed to assess the effect of HAL training on the walking ability, range of motion (ROM), and muscle strength of patients after total knee arthroplasty (TKA) for osteoarthritis and rheumatoid arthritis, and to compare the functional status after HAL training to the conventional training methods after surgery.MethodsNine patients (10 knees) underwent HAL training (mean age 74.1 ± 5.7 years; height 150.4 ± 6.5 cm; weight 61.2 ± 8.9 kg), whereas 10 patients (11 knees) underwent conventional rehabilitation (mean age 78.4 ± 8.0 years; height 150.5 ± 10.0 cm; weight 59.1 ± 9.8 kg). Patients underwent HAL training during 10 to 12 (average 14.4 min a session) sessions over a 4-week period, 1 week after TKA. There was no significant difference in the total physical therapy time including HAL training between the HAL and control groups. Gait speed, step length, ROM, and muscle strength were evaluated.ResultsThe nine patients completed the HAL training sessions without adverse events. The walking speed and step length in the self-selected walking speed condition, and the walking speed in the maximum walking speed condition were greater in the HAL group than in the control group at 4 and 8 weeks (P < 0.05). The step length in the maximum walking speed condition was greater in the HAL group than in the control group at 2, 4, and 8 weeks (P < 0.05). The extension lag and knee pain were lower in the HAL group than in the control group at 2 weeks (P < 0.05). The muscle strength of knee extension in the HAL group was greater than that in the control group at 8 weeks (P < 0.05).ConclusionHAL training after TKA can improve the walking ability, ROM, and muscle strength compared to conventional physical therapy for up to 8 weeks after TKA. Since the recovery of walking ability was earlier in the HAL group than in the control group and adverse events were not observed in this pilot study, HAL training after TKA can be considered a safe and effective rehabilitation intervention

Calcium phosphate-hybridized tendon graft to enhance tendon-bone healing two years after ACL reconstruction in goats

Abstract Background We developed a novel technique to improve tendon-bone attachment by hybridizing calcium phosphate (CaP) with a tendon graft using an alternate soaking process. However, the long-term result with regard to the interface between the tendon graft and the bone is unclear. Methods We analyzed bone tunnel enlargement by computed tomography and histological observation of the interface and the tendon graft with and without the CaP hybridization 2 years after anterior cruciate ligament (ACL) reconstruction in goats using EndoButton and the postscrew technique (CaP, n = 4; control, n = 4). Results The tibial bone tunnel enlargement rates in the CaP group were lower than those in the control group (p p p Conclusions The CaP-hybridized tendon graft enhanced the tendon-bone healing 2 years after ACL reconstruction in goats. The use of CaP-hybridized tendon grafts can reduce the bone tunnel enlargement and gap area associated with the direct insertion-like formation in the interface near the joint.</p

筋運動、運動解析、床反力データを用いた歩行中の荷重応答期における膝関節CT-FEMモデルの開発

東京都立大

Enhanced wound healing associated with Sharpey’s fiber-like tissue formation around FGF-2-apatite composite layers on percutaneous titanium screws in rabbits

BACKGROUND:Pin-tract infections are the most common complications of external fixation. To solve the problem, we developed a fibroblast growth factor-2 (FGF-2)-apatite composite layer for coating titanium screws. The purpose of this study was to elucidate the mechanism of the improvement in infection resistance associated with FGF-2-apatite composite layers.METHOD:We analyzed FGF-2 release from the FGF-2-apatite composite layer and the mitogenic activity of the FGF-2-apatite composite layer. We evaluated time-dependent development of macroscopic pin-tract infection around uncoated titanium control screws (n = 10). Screws coated with the apatite layer (n = 16) and FGF-2-apatite composite layer (n = 16) were percutaneously implanted for 4 weeks in the medial proximal tibia in rabbits.RESULTS:A FGF-2-apatite composite layer coated on the screws led to the retention of the mitogenic activity of FGF-2. FGF-2 was released from the FGF-2-apatite composite layer in vitro for at least 4 days, which corresponds to a period when 30% of pin-tract infections develop macroscopically in the percutaneous implantation of uncoated titanium control screws. The macroscopic infection rate increased with time, reaching a plateau of 80-90% within 12 days. This value remained unchanged until 4 weeks after implantation. The screws coated with an FGF-2-apatite composite layer showed a significantly higher wound healing rate than those coated with an apatite layer (31.25 vs. 6.25%, p < 0.05). The interfacial soft tissue that bonded to the FGF-2-apatite composite layer is a Sharpey\u27s fiber-like tissue, where collagen fibers are inclined at angles from 30 to 40° to the screw surface. The Sharpey\u27s Wber-like tissue is rich in blood vessels and directly bonds to the FGF-2-apatite composite layer via a thin cell monolayer (0.8-1.7 μm thick).CONCLUSION:It is suggested that the enhanced wound healing associated with the formation of Sharpey\u27s fiber-like tissue triggered by FGF-2 released from the FGF-2-apatite composite layer leads to the reduction in the pin-tract inflammation rate

Cell death and cell proliferation in cartilage layers in human anterior cruciate ligament tibial insertions after rupture

The purpose of this study is to investigate cellular responses and histological changes of cartilaginous layers in human anterior cruciate ligament (ACL) tibial insertions after rupture compared with those in normal insertions. Fully 16 tibial insertions of ruptured ACLs were obtained during primary ACL reconstructions. We also obtained 16 normal ACL tibial insertions from cadavers. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) to detect apoptosis, proliferating cell nuclear antigen (PCNA) staining, and histological examination were performed. The percentage of TUNEL-positive chondrocytes in ruptured ACL insertions (30.2 ± 15.6%) was higher than that in normal insertions (9.6 ± 5.8%). The percentage of PCNA-positive chondrocytes was significantly different between ruptured ACL insertions (19.9 ± 15.0%) and normal insertions (12.3 ± 7.3%). The average thickness of the cartilage layer, the glycosaminoglycan-stained area, and the number of chondrocytes per millimeter in ruptured ACL insertions was smaller than those in normal insertions. The decrease in the number of chondrocytes owing to an imbalance between cell death and cell proliferation in the ACL insertions after rupture, as compared with normal insertions, may lead to histological changes of the cartilage layer in the insertions. An in-depth understanding of injured ACL insertion may help elucidate the etiology of histological changes and the function and significance of the existence of the cartilage layer of insertion. This understanding may help in developing optimal treatment protocols for ACL injuries if apoptosis and cell proliferation are controlled

Intra-articular injection of tranexamic acid via a drain plus drain-clamping to reduce blood loss in cementless total knee arthroplasty

<p>Abstract</p> <p>Background</p> <p>Patients undergoing cementless total knee arthroplasty (TKA) sometimes suffer large blood loss. In a retrospective study, we explored whether postoperative intra-articular retrograde injection of tranexamic acid (TA) and leaving a drain clamp in place for 1 h reduced blood loss.</p> <p>Patients and methods</p> <p>Patients (<it>n</it> = 140) treated with unilateral primary cementless TKA (posterior cruciate ligament retained) were divided into two groups: those who had an intra-articular injection of TA (1000 mg) and drain clamping for 1 h postoperatively (study group, <it>n</it> = 70) and those who were not given TA and did not undergo clamping of their drains (control group, <it>n</it> = 70). Postoperative total blood loss, volume of drainage, hemoglobin level, transfusion amounts and rates, D-dimer level at postoperative day (POD) 7, and complications were recorded.</p> <p>Results</p> <p>Total blood loss, total drainage, mean transfusion volume, and transfusion rates were lower in the study group than in controls (<it>P</it> < 0.001). Hemoglobin levels on PODs 1 and 14 were similar in the groups, but on POD 7 the hemoglobin level was higher in the study group than in controls (<it>P</it> < 0.001). D-dimer level on POD 7 was lower in the study group than in controls (<it>P</it> < 0.05). There were no complications in either group.</p> <p>Conclusions</p> <p>Immediately postoperative intra-articular retrograde injection of TA and 1 h of drain-clamping effectively reduced blood loss and blood transfusion after cementless TKA. We believe that this method is simple, easy, and suitable for these patients.</p

Relationships between Quadriceps Tendon Elasticity and Knee Flexion Angle in Young Healthy Adults

Background and objectives: Although tendon elasticity by elastography is useful for diagnosing tendon disorders and planning rehabilitation regimens of the tendon, there are few reports on the quadriceps tendon. Moreover, relationships between the quadriceps tendon elasticity and knee angle have not been investigated. The purpose of this study was to clarify the relationship between quadriceps tendon elasticity and knee flexion angle in young healthy adults using elastography, and to investigate the difference in elasticity by sex and leg dominance. Materials and Methods: A total of 40 knees in 20 young healthy adults were included in this study (age: 25.5 (23.3&#8315;27.5) years). At knee flexion of 30&#176;, 60&#176;, and 90&#176;, quadriceps tendon elasticity was measured using ShearWave&#8482; Elastography during the ultrasound examination. Results: There were significant differences in the elasticity between all angles (p &lt; 0.001). Elasticity was increased more at 60&#176; than at 30&#176; and at 90&#176; than at 60&#176;. Elasticity in men was higher than that in women at 60&#176; (p = 0.029). There were no differences (p = 0.798) in elasticity at each angle between the dominant and non-dominant legs. Conclusions: The quadriceps tendon elasticity increased according to the knee flexion angle in young healthy adults. Moreover, elasticity was affected by sex, but not by leg dominance. Clinically, in a rehabilitation regimen, attention should be paid to exercises that could increase stiffness accompanying flexion of the knee to avoid further tendon damage as risk management in the acute phase