Pitfalls during biomechanical testing — Evaluation of different fixation methods for measuring tendons endurance properties

The goal of the study was to find a proper technique to fix tendon grafts into an INSTRON loading machine. From 8 human cadavers, 40 grafts were collected. We removed the bone-patella tendon-bone grafts, the semitendinosus and gracilis tendons, the quadriceps tendon-bone grafts, the Achilles tendons, and the peroneus longus tendons from each lower extremity. We tested the tendon grafts with five different types of fixation devices: surgical thread (Premicron 3), general mounting clamp, wire mesh, cement fixation, and a modified clamp for an INSTRON loading machine. The mean failure load in case of surgical thread fixation was (381N ± 26N). The results with the general clamp were (527N ± 45N). The wire meshes were more promising (750N ± 21N), but did not reach the outcomes we desired. Easy slippages of the ends of the tendons from the cement encasements were observed (253N ± 18N). We then began to use Shi’s clamp that could produce 977N ± 416N peak force. We combined Shi’s clamp with freezing of the graft and the rupture of the tendon itself demonstrated an average force of 2198 N ± 773N. We determined that our modified frozen clamp fixed the specimens against high tensile forces

Semitendinosus ínnal végzett egyköteges és kétköteges, négycsatornás elülső keresztszalag pótlással elért eredményeink prospektív összehasonlító vizsgálata

Authors compared the results of the most frequent quadrupled single bundle ACL replacement and of the nowadays spreading use of double bundle four channel ACL replacement with semitendinosus tendon. The prospective examination included 40 patients with traditional ACL replacement technique and 40 patients with double bundle ACL replacement technique. During the 6–42 months follow up period, the results were evaluated based on subjective complaints, point systems, manual articular stability and the results of AP directional movement of the caput tibiae measured with KT-1000 arthrometer.No differences were found between the two groups in regard to complications. Subjective complaints and point systems did not show signifi cant differences either. Measuring objective stability showed better results in the double bundle group – the size of displacement with double bundle ACL replacement was on average 6.1 mm whereas that with traditional ACL replacement was 7.2 mm. Most of the athletes were able to return to their original activity level. 25 out of 28 athletes were able to return to competition level. These results are promising compared with the data in the literature. Although these initial experiences are encouraging, a longer follow up period is needed to decide whether the double bundle method – which is technically more complex, more expensive, and needs more time and special instruments – possesses chondroprotective  advantages over the traditional ACL replacement.A szerzők a ma leggyakrabban használt megnégyszerezett semitendinosus ínnal való egyköteges LCA pótlás műtéti eredményeit prospektív módszerrel hasonlították össze a napjainkban elterjedőben lévő szintén semitendinosus ínból készült, kétköteges, négycsatornás módszer műtéti eredményeivel. Prospektív vizsgálat során 40-40 hagyományos technikával végzett és kétköteges LCA pótláson átesett beteg 6-42 hónapos utánkövetése során a szubjektív panaszok, pontrendszerek, manuális stabilitásvizsgálat és a tibiafej AP kimozdulásának KT-1000 arthrométerrel mért értéke alapján értékeltek. Szövődményeket illetően a két csoport nem mutatott különbséget. A szubjektív panaszok és a pontrendszerek vonatkozásában a két csoport betegeinek eredménye között szignifikáns eltérés nem mutatkozott. Az objektív stabilitás mérések a kétköteges csoport esetében jobb eredményeket mutattak – átlagosan 6,1 mm kimozdulás a hagyományos technikával végzett 7,2 mm-es átlagkimozdulásához képest. Mindkét csoportból a legtöbben vissza tudtak térni a sérülés előtti aktivitásukhoz. Összesen 28 igazolt sportolóból 25-en a versenysportba is visszatértek. Ez az eredmény az irodalmi adatokkal összevetve is ígéretesnek mondható. Bár a kezdeti tapasztalatok bíztatóak, hosszabb távú utánkövetésre lenne szükség annak eldöntésére, hogy a technikailag összetettebb, költségesebb és több időt valamint speciális műszereket igénylő kétköteges módszer chondroprotectív hatás szempontjából lényeges előnyökkel bír-e a hagyományos LCA pótlással szemben.   DOI: 10.17489/biohun/2010/2/0

Does compression sensory axonopathy in the proximal tibia contribute to noncontact anterior cruciate ligament injury in a causative way?—a new theory for the injury mechanism

Anterior cruciate ligament injury occurs when the ligament fibers are stretched, partially torn, or completely torn. The authors propose a new injury mechanism for non-contact anterior cruciate ligament injury of the knee. Accordingly, non-contact anterior cruciate ligament injury could not happen without the acute compression microinjury of the entrapped peripheral proprioceptive sensory axons of the proximal tibia. This would occur under an acute stress response when con-comitant microcracks-fractures in the proximal tibia evolve due to the same excessive and repetitive compression forces. The primary damage may occur during eccentric contractions of the acceleration and deceleration moments of strenuous or unaccustomed fatiguing exercise bouts. This primary damage is suggested to be an acute compression/crush axonopathy of the proprioceptive sensory neurons in the proximal tibia. As a result, impaired proprioception could lead to injury of the anterior cruciate ligament as a secondary damage, which is suggested to occur during the deceleration phase. Elevated prostaglandin E2, nitric oxide and glutamate may have a critical neuro-modulatory role in the damage signaling in this dichotomous neuronal injury hypothesis that could lead to mechano-energetic failure, lesion and a cascade of inflammatory events. The presynaptic modulation of the primary sensory axons by the fatigued and microdamaged proprioceptive sensory fibers in the proximal tibia induces the activation of N-methyl-D-aspartate receptors in the dorsal horn of the spinal cord, through a process that could have long term relevance due to its contribution to synaptic plasticity. Luteinizing hormone, through interleukin-1β, stimulates the nerve growth factor-tropomyosin receptor kinase A axis in the ovarian cells and promotes tropomyosin receptor kinase A and nerve growth factor gene expression and prostaglandin E2 release. This luteinizing hormone induced mechanism could further elevate prostaglandin E2 in excess of the levels generated by osteocytes, due to mechanical stress during strenuous athletic moments in the pre-ovulatory phase. This may explain why non-contact anterior cruciate ligament injury is at least three-times more prevalent among female athletes

Evaluation of biomarkers following autologous osteochondral transplantation in the equine stifle joint — An experimental study

The purpose of this study was to evaluate changes in biomarker and synovial parameters following autologous osteochondral transplantation (AOT) in the equine stifle joint, to test the hypothesis whether synovial parameters would show significant differences at selected time points following the surgery (at days 3, 14, 60 and 180) compared to baseline level (at day 0). Surgical intervention was performed in both stifles of nine horses (n = 18). The joints were randomly assigned to operated and sham-operated groups. Grafts 8.5 mm in diameter were harvested from the femoropatellar (FP) joint under arthroscopic control and the medial femorotibial (MFT) joints had AOT using mosaicplasty (MP) instrumentation, while the sham FP and sham MFT joints underwent arthroscopy and miniarthrotomy without transplantation, respectively. Synovial fluid (SF) parameters were evaluated at days 4, 14, 60 and 180. Data were analysed by two-way repeated- measures analysis of variance (ANOVA), and P < 0.05 was considered significant. During the first 10–14 days after surgery, lameness of degree 2–3/5 [American Association of Equine Practitioners (AAEP) scores] was present, which disappeared after 60 days. Joints with transplantation showed significant increases in synovial white blood cell count (WBC), total protein (TP), substance P, C1,2C and CS846 epitope concentration at day 3 compared to baseline and shamoperated joints (P < 0.05). These parameters returned to the baseline values by two months after surgery and remained within normal levels at 6 months postoperatively

Late cardiac effect of anthracycline therapy in physically active breast cancer survivors - a prospective study

The late-onset cardiotoxic effect of anthracycline is known, however the early detection and prevention of subclinical myocardial damage has not been fully understood yet. Besides medical therapy regular physical activities may also play a role in the prevention and reduction of side effects of chemotherapy. The aim of our present study was to detect the effect of regular physical activities on the diastolic function and on the symptoms of late heart failure in case of anthracycline chemotherapy. The prospective study included 55 female patients (age 31-65 year, average 49.5 years) with breast cancer and no cardiovascular risk factors. Proper cardiologic checkup included physical examination (blood pressure, pulse, etc.), ECG, standard echocardiography parameters (EF, LV dimensions etc.) and specific tissue Doppler (TDI) measurements. Symptoms of heart failure were also recorded. After five years of follow-up, symptoms of heart failure were evaluated again. Patients were assigned into two groups depending on their physical activity: 36 patients did perform regular physical activities (mean age 49.2 years) and 19 patients did not (average age 50.1 years). There was no significant difference between the two groups in basic physiological or standard echocardiography parameters neither at the baseline nor at the later time points. Diastolic dysfunction (decreased E/A) was detected 6 months after the beginning of the treatment (T2 time point) in both groups. In the inactive group this value fell below one however there was no significant difference (1.1+/-0.25 vs. 0.95+/-0.22). One year after the beginning of the treatment (T3) a significant difference could be detected between the two groups (1.05+/-0.28 vs. 0.86+/-0.25. P=0.038). Consistent change in diastolic function (Ea/Aa) could be detected with the more sensitive TDI (Tissue Doppler Imaging) measurements after treatments in both groups, especially in the septal segment (in the non active group the Ea/Aa decreased markedly but not significantly at T2 - 1.1+/-0.55 vs. 0.81+/-0.44, and this difference became significant at T3 and 2 years after treatment (T4), p=0.007 and p=0.065). The filling pressure (E/Ea) rose above 10 (p=0.09) in the non active group at T2; and it kept rising in both groups and became significant at T3 (p=0.012). Five years after the onset of the treatment symptoms of heart failure were less frequently reported in the physically active group than in the inactive one (19.45% vs. 68.42%). The data of our study show that the diastolic dysfunction of the left ventricle related to the anthracycline therapy became evident in the physically active group later and the symptoms of heart failure were less frequent than in the non active group after five years period. Enrollment in sport activities could be a good means for partial prevention in this group of patients. Cardiologic checkup at proper intervals plays a pivotal role in detection of possible cardiotoxicity. This is a strong indication for changes in the lifestyle of the patient and the treatment protocol alike