Evidence-Based Medicine (EBM) is properly perceived but its application is still limited in the orthopedic clinical practice: an online survey among the European Society of Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA) members.

PURPOSE: To evaluate the knowledge and awareness of Evidence-Based Medicine (EBM) among members of the European Society of Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA). METHODS: A questionnaire was developed that explored the following areas: (i) respondents' attitudes to EBM; (ii) their motivation to implement EBM in daily practice; (iii) their educational background, knowledge and skills related to accessing and interpreting information; (iv) their level of attention to, and use of, scientific literature; (v) access to and availability of evidence; (vi) perceived barriers in using EBM in clinical practice. The resulting data were analyzed using descriptive statistics, and the correlation between age, educational background and country was further investigated. RESULTS: Two-hundred and eighty-eight ESSKA members (11% of the total population) compiled the questionnaire. The participants covered all the five continents and an expected prevalence of European professionals (77%) was observed. The vast majority of participants were medical doctors (91%), mainly specialized in knee surgery with minimal involvement in research. 97% of the participants declared having some knowledge of EBM, acquired mainly during their professional education, with some geographical differences. The youngest clinicians and those from Eastern Europe reported the greatest difficulty in using EBM in daily practice. The application of EBM in clinical practice is positively affected by the time dedicated to research and negatively correlates with the time dedicated to patient care. CONCLUSIONS: The results of this survey highlight the need for further investigation into the main reasons behind the limited diffusion of the EBM approach, despite the medical community's knowledge and interest in the concept. A wider application of EMB would upgrade clinical practice, linking medical knowledge and scientific evidence to patients' needs which would result of benefit to patients, but also more in general to the health system.

DNA methylation variations are required for epithelial-to-mesenchymal transition induced by cancer-associated fibroblasts in prostate cancer cells.

Widespread genome hypo-methylation and promoter hyper-methylation of epithelium-specific genes are hallmarks of stable epithelial-to-mesenchymal transition (EMT), which in prostate cancer (PCa) correlates with castration resistance, cancer stem cells generation, chemoresistance and worst prognosis. Exploiting our consolidated 'ex-vivo' system, we show that cancer-associated fibroblasts (CAFs) released factors have pivotal roles in inducing genome methylation changes required for EMT and stemness in EMT-prone PCa cells. By global DNA methylation analysis and RNA-Seq, we provide compelling evidence that conditioned media from CAFs explanted from two unrelated patients with advanced PCa, stimulates concurrent DNA hypo- and hyper-methylation required for EMT and stemness in PC3 and DU145, but not in LN-CaP and its derivative C4-2B, PCa cells. CpG island (CGI) hyper-methylation associates with repression of genes required for epithelial maintenance and invasion antagonism, whereas activation of EMT markers and stemness genes correlate with CGI hypo-methylation. Remarkably, methylation variations and EMT-regulated transcripts almost completely reverse qualitatively and quantitatively during MET. Unsupervised clustering analysis of the PRAD TCGA data set with the differentially expressed (DE) and methylated EMT signature, identified a gene cluster of DE genes defined by a CAF+ and AR- phenotype and worst diagnosis. This gene cluster includes the relevant factors for EMT and stemness, which display DNA methylation variations in regulatory regions inversely correlated to their expression changes, thus strongly sustaining the ex-vivo data. DNMT3A-dependent methylation is essential for silencing epithelial maintenance and EMT counteracting genes, such as CDH1 and GRHL2, that is, the direct repressor of ZEB1, the key transcriptional factor for EMT and stemness. Accordingly, DNMT3A knock-down prevents EMT entry. These results shed light on the mechanisms of establishment and maintenance of coexisting DNA hypo- and hyper-methylation patterns during cancer progression, the generation of EMT and cell stemness in advanced PCa, and may pave the way to new therapeutic implications.

Sport and early osteoarthritis: the role of sport in aetiology, progression and treatment of knee osteoarthritis.

Sports activities are considered favourable for general health; nevertheless, a possible influence of sports practice on the development of early osteoarthritis (OA) is a cause for concern. A higher incidence of OA in knees and ankles of former high-impact sports players than in those of the normal population has been shown and it is still debatable whether the cause is either to be recognized generically in the higher number of injuries or in a joint overload. The possibility to address knee OA in its early phases may be strictly connected to the modification of specific extrinsic or intrinsic factors, related to the patient in order to save the joint from further disease progression; these include sport practice, equipment and load. Non-surgical therapies such as continuative muscles reinforce and training play a strong role in the care of athletes with early OA, particularly if professional. There is an overall agreement on the need of an early restoring of a proper meniscal, ligament and cartilage integrity in order to protect the knee and resume sports safely, whereas alignment is a point still strongly debatable especially for professional athletes. Remaining questions still to be answered are the risks of different sports in relation to one another, although an actual protective effect of low-impact sports, such as walking, swimming or cycling, has been recognized on the appearance or worsening of OA, the effect of continuing or ceasing to practice a sport on the natural history of early OA, and even following appropriate treatment is still unknown.

Trans-physeal anterior cruciate ligament reconstruction in adolescents.

PURPOSE: The aim of the study was to evaluate, in a group of adolescents, the onset of varus-valgus deviations in the sagittal plane after performing a trans-tibial trans-epiphyseal technique of ACL reconstruction with a follow-up of at least 2 years. METHODS: Seventy-one patients aged 12-15 years old (Tanner scale 3 and 4) have undergone ACL reconstruction with STG using arthroscopy. All patients were evaluated clinically using the visual analogue scale (VAS), the Lysholm score and the Tegner activity score at the time of surgery. All patients were reevaluated after a follow-up period of at least 2 years (T1) using the VAS, the Lysholm score, the Tegner activity score and radiographic studies in order to compare the operated limb with the healthy control limb. RESULTS: Valgus difference exceeding 2° in the knee axis between the operated limb and the healthy control limb was observed only in three patients (4.2%: 95% CI 0.88-11.86%). The average difference was <1° (0.3°, 95% CI 0.0-0.55). CONCLUSION: The trans-tibial trans-epiphyseal technique of ACL reconstruction, according to the results obtained, seems to be a valid alternative procedure, when performed by a skilled orthopaedic surgeon, offering an excellent safety profile and at the same time very good clinical results. LEVEL OF EVIDENCE: IV.

High accuracy in knee alignment and implant placement in unicompartmental medial knee replacement when using patient-specific instrumentation.

PURPOSE: The influence of patient-specific instrumentations on the accuracy of unicompartmental medial knee replacement remains unclear. The goal of this study was to examine the ability of patient-specific instrumentation to accurately reproduce postoperatively what the surgeon had planned preoperatively. METHODS: Twenty consecutive patients (20 knees) who suffered from isolated unicompartmental medial osteoarthritis of the knee and underwent medial knee replacement using newly introduced magnetic resonance imaging-based patient-specific instrumentation were assessed. This assessment recorded the following parameters: (1) the planned and the postoperative mechanical axis acquired through long-leg AP view radiographies; (2) the planned and the postoperative tibial slope acquired by means of standard AP and lateral view radiographies; and (3) the postoperative fit of the implanted components to the bone in coronal and sagittal planes. The hypothesis of the study was that there was no statistically significant difference between postoperative results and preoperatively planned values. RESULTS: The study showed that (1) the difference between the postoperative mechanical axis (mean 1.9° varus ± 1.2° SD) and the planned mechanical axis (mean 1.8° varus ± 1.2° SD) was not statistically significant; (2) the difference between the postoperative tibial slope (mean 5.2° ± 0.6° SD) and the planned tibial slope (mean 5.4° ± 0.6° SD) was statistically significant (p = 0.008); and (3) the postoperative component fit to bone in the coronal and sagittal planes was accurate in all cases; nevertheless, in one knee, all components were implanted one size smaller than preoperatively planned. Moreover, in two additional cases, one size thinner and one size thicker of the polyethylene insert were used. CONCLUSIONS: This study suggests that overall patient-specific instrumentation was highly accurate in reproducing postoperatively what the surgeon had planned preoperatively in terms of mechanical axis, tibial slope and component fit to bone. LEVEL OF EVIDENCE: IV.

Why menisci show higher healing rate when repaired during ACL reconstruction? Growth factors release can be the explanation.

PURPOSE: Healing rate of meniscus repair is higher when the suture is associated with anterior cruciate ligament reconstruction. A possible explanation can be a different pattern of release of growth factors between anterior cruciate ligament reconstruction and isolated meniscus surgery. Hypothesis of this study is that the concentrations of bFGF, TGF-ß and platelet-derived growth factor (PDGF) in joint fluid, immediately after single-bundle anterior cruciate ligament reconstruction and arthroscopic partial meniscectomy, can be different. METHODS: Twenty consecutive patients underwent partial medial meniscectomy and twenty consecutive patients underwent single-bundle anterior cruciate ligament reconstruction with hamstring grafts were enrolled in the study. Thirty minutes after the end of the surgical procedure, a sample of joint fluid, as well of venous blood, was collected from all the patients. Concentrations of growth factors were determined by enzyme-linked immunosorbent assay. RESULTS: The peripheral blood concentration of TGF-ß, bFGF and PDGF was comparable between partial meniscectomy and anterior cruciate ligament reconstruction groups. No differences between the two surgical techniques were also found in term of TGF-ß and bFGF joint fluid concentration, whereas joint PDGF concentration of anterior cruciate ligament reconstruction patients was significantly higher than the one found in partial meniscectomy patients. CONCLUSIONS: A significant growth factors release was detected in the knee joint during arthroscopic surgery. PDGF concentration was significantly higher in anterior cruciate ligament reconstructed knee than in the meniscectomy group. PDGF can play an important role enhancing the healing response of meniscus suture and can be one of the biological reasons of the higher meniscal healing rate in anterior cruciate ligament reconstructed knee.

Autologous platelet-rich plasma gel to reduce donor-site morbidity after patellar tendon graft harvesting for anterior cruciate ligament reconstruction: a randomized, controlled clinical study.

PURPOSE: Bone-patellar tendon-bone technique (BPTB) for anterior cruciate ligament injuries is associated with a higher risk of donor-site morbidity. To evaluate whether platelet-rich plasma (PRP), due to its anti-inflammatory properties and capacity to stimulate tissue regeneration, was able to reduce the anterior knee pain, the kneeling pain, and donor-site morbidity, as evidenced by evaluation of VISA and VAS scoring scales and MRI analysis of the tendon and bone defect, we performed a clinical randomized controlled study where PRP gel was applied to donor site after ACL reconstruction with BPTB. METHODS: Forty young athletes with the indication of ACL reconstruction with patellar tendon grafts were randomly assigned to group A (n = 20 patients, control group) or group B (n = 20 patients, PRP group). The autologous PRP gel was applied to both the patellar and tendon bone plug harvest site and stabilized by the peritenon suture. At 12-month follow-up, all patients underwent clinical examination and VAS and VISA questionnaires, respectively, evaluating the average daily pain of the knee and the pain during particular activities involving the knee, were filled. MRI at the same time point was also performed. RESULTS: VISA scores were significantly higher in the patients treated with PRP (84.5 ± 11.8 and 97.8 ± 2.5 for group A and for group B; P = 0.041), whereas no significant difference in postoperative VAS scores between the two groups was observed (1 ± 1.4 and 0.6 ± 0.9 for group A and group B, n.s.). In 85% of PRP group patients, the tibial and patellar bone defect was satisfactorily filled by new bony tissue (>70% of bone gap filled), whereas this percentage was just of 60% in control group patients, but this difference was not statistically significant. CONCLUSIONS: The study shows the usefulness of PRP in reducing subjective pain at the donor-site level after ACL reconstruction with BPTB. However, this approach deserves further investigations to confirm PRP efficacy and to elucidate its mechanism of action. LEVEL OF EVIDENCE: Prospective randomized controlled study, Level I.

Advantages of 70° arthroscope in management of ECRB tendinopathy.

Lateral epicondylitis requires a challenging therapeutic management even for expert surgeons. With the failure of conservative treatment, the physician should consider a surgical choice. The purpose of the surgical procedure is to excise the degenerated tissue of extensor carpi radialis brevis tendon. This article describes the arthroscopic release, performed under direct visualization with a 70° scope; the aim is to encourage the use of this type of lens, versus the traditional 30° one. The patient is positioned in a modified lateral decubitus. After joint distension, a diagnostic arthroscopy of the posterior compartment is performed as first step. Then, an anterior compartment arthroscopic evaluation, a subsequent antero-lateral capsulectomy, and extensor carpi radialis brevis tendon exposition are performed with a 30° view. At this point, the 70° lens is switched and the tendon release is performed under direct control. The 70° lens allows a safer procedure, but requires a dedicated learning curve.

High articular levels of the angiogenetic factors VEGF and VEGF-receptor 2 as tissue healing biomarkers after single bundle anterior cruciate ligament reconstruction.

Various factors may account for the positive association between meniscal repair and anterior cruciate ligament reconstruction, one being the modulation of healing response of meniscal fibrochondrocytes by growth factors released with intra-articular bleeding and fibrin clot formation. Analysis of vascular endothelial growth factor (VEGF) and its receptors, VEGFR1 and VEGFR2, may be useful in the clinical assessment of bone and soft-tissue remodeling. We measured systemic and local levels of VEGF (VEGF165), VEGFR1 and VEGFR2 after either arthroscopic partial meniscectomy (APM) or single-bundle anterior cruciate ligament reconstruction (ACLR) in order to determine the local effect of bone tunnelling and notchplasty on the release of these growth factors. The study population included 40 patients: 20 consecutive patients had undergone ACLR with hamstring grafts and 20 had undergone APM. Thirty minutes after the end of the operation, knee joint fluid samples were collected via the drainage tube and at the same time venous blood samples were drawn. In both sets of samples, VEGF, VEGFR1 and VEGFR2 concentrations were determined by enzyme-linked immunosorbent assay (ELISA). No significant differences in VEGF, VEGFR1 or VEGFR2 concentrations in the venous blood were observed between the two treatment groups. In contrast, VEGF and VEGFR2 levels were significantly higher in the knee joint fluid of the ACLR group; furthermore, VEGF and VEGFR1 were significantly higher in the knee joint fluid than in the venous blood, whereas VEGFR2 was lower in the knee joint fluid than in the venous blood. Local release of VEGF and its angiogenetic receptor VEGFR2, but not the negative regulator VEGFR1, was significantly higher after ACLR than after APM, indicating a better vasculogenic potential for enhanced bone-graft and meniscus healing. These results could suggest that VEGF and VEGFRs could be considered as good biomarkers of tissue healing after knee joint surgery.

Virp1 is a host protein with a major role in Potato spindle tuber viroid infection in Nicotiana plants.

Viroids are small, circular, single-stranded RNA molecules that, while not coding for any protein, cause several plant diseases. Viroids rely for their infectious cycle on host proteins, most of which are likely to be involved in endogenous RNA-mediated phenomena. Therefore, characterization of host factors interacting with the viroid may contribute to the elucidation of RNA-related pathways of the hosts. Potato spindle tuber viroid (PSTVd) infects several members of the Solanaceae family. In an RNA ligand screening we have previously isolated the tomato protein Virp1 by its ability to specifically interact with PSTVd positive-strand RNA. Virp1 is a bromodomain-containing protein with an atypical RNA binding domain and a nuclear localization signal. Here we investigate the role of Virp1 in the viroid infection cycle by the use of transgenic lines of Nicotiana tabacum and Nicotiana benthamiana that either overexpress the tomato Virp1 RNA or suppress the orthologous Nicotiana genes through RNA silencing. Plants of the Virp1-suppressed lines were not infected by PSTVd or Citrus exocortis viroid through mechanical inoculation, indicating a major role of Virp1 in viroid infection. On the other hand, overexpression of tomato Virp1 in N. tabacum and N. benthamiana plants did not affect PSTVd KF 440-2 infectivity or symptomatology in these species. Transfection experiments with isolated protoplasts revealed that Virp1-suppressed cells were unable to sustain viroid replication, suggesting that resistance to viroid infection in Virp1-suppressed plants is likely the result of cell-autonomous events.

The role of the rehabilitation brace in restoring knee extension after anterior cruciate ligament reconstruction: a prospective controlled study.

To evaluate the effects of a rehabilitation brace locked in extension for the first week on the recovery of full extension after ACL reconstruction we compared two groups of subjects who underwent ACL bone-patellar tendon-bone reconstruction. The brace was unlocked twice a day for assisted physiotherapy. In Group A, 18 male subjects wore a post-operative brace locked from 0 degrees to 90 degrees. In Group B, 18 male subjects wore the same post-op brace locked in full extension for the first week. In both groups the brace was unlocked (0 degrees -120 degrees ) at the beginning of the second postoperative week, and then removed at the beginning of the third week. All the subjects followed the same rigorous, accelerated rehabilitation protocol. Each subject was evaluated pre and post-operatively (at second, fourth and eighth week) with bubble-level heel height difference (HHD) measurements and KT 1000 arthrometric assessment at the fourth postoperative month. Preoperative bubble-level HHD measurements of the two groups were statistically similar (Group A 0.6 cm, Group B 1 cm; not significant, n.s.). At the fourth week (Group A 2.2 cm, Group B 0.6 cm) and eighth week (Group A 1.6 cm, Group B 0.1 cm) follow-ups, bubble-level HHD measurements showed that the extension of the operated knees of Group B was significantly greater than in Group A. KT 1000 arthrometric scores showed no difference between the two groups (Group A 1.8 mm, Group B 1.5; n.s.).

Replicating potato spindle tuber viroid RNA is accompanied by short RNA fragments that are characteristic of post-transcriptional gene silencing.

The low molecular weight fraction of tomato plants inoculated with potato spindle tuber viroid (PSTVd) contains a population of short PSTVd-specific RNAs of either polarity. The main constituents were RNAs of 22 and 23 nt representing different domains of the viroid genome. The occurrence of such distinct RNA species indicated that the nuclear replicating PSTVd RNA induces post-transcriptional gene silencing. The short RNAs were slightly more abundant at 30 days post-inoculation than at later stages and were present in plants infected with a mild, severe or lethal isolate of PSTVD: There was no apparent correlation between the quantity of small PSTVd-specific RNAs and the degree of virulence of the viroid isolate.

Motor control performance in the lower extremity: normals vs. anterior cruciate ligament reconstructed knees 5-8 years from the index surgery.

We compared motor control function in 50 patients who had undergone anterior cruciate ligament reconstruction using a bone-tendon-bone graft to that in 50 normal controls. Surgical subjects patients had undergone reconstruction with a one- (n=37) or two-incision (n=13) technique with the same rehabilitation protocol; mean time from the index surgery was 6.1 years (range of 5-8 years). For inclusion patients required an excellent outcome, category A IKDC score, and a KT-1000 side-to-side difference of 3 mm or less. Motor control evaluations were conducted using the KAT 2000 with static and dynamic tests. Normal controls had substantially better scores than did the surgical patients. There was no statistical difference the single-limb static test between scores of operated and nonoperated limbs. However, the operated limb scores were slightly better overall than those for the nonoperated limb, and the right knee scores tended to be better than those for the left knee. This may be explained by limb dominance. The test method employed in this investigation shows that anterior cruciate ligament reconstructed patients had a clear motor control deficit compared to normal control subjects even after several years.

A novel RNA-binding protein from Triturus carnifex identified by RNA-ligand screening with the newt hammerhead ribozyme.

The newt hammerhead ribozyme is transcribed from Satellite 2 DNA, which consists of tandemly repeated units of 330 bp. However, different transcripts are synthesized in different tissues. In all somatic tissues and in testes, dimeric and multimeric RNA transcripts are generated which, to some extent, self-cleave into monomers at the hammerhead domain. In ovaries, primarily a distinct monomeric unit is formed by transcription, which retains an intact hammerhead self-cleavage site. The ovarian monomeric RNA associates to form a 12S complex with proteins that are poorly characterised so far. In this work we identified NORA, a protein that binds the ovarian form of the newt ribozyme. We show that the newt ribozyme binds to the Escherichia coli -expressed protein, as well as to a protein of identical size that is found exclusively in newt ovaries. Also NORA mRNA was detectable only in ovary, but in neither somatic tissues nor testes. The tissue-specific expression of NORA is analogous to the ovary-specific transcription of the newt ribozyme. Although NORA was identified by its ability to bind to the newt ribozyme in the presence of a vast excess of carrier RNA, it was able to interact with certain other RNA probes. This novel RNA-binding protein does not contain any motif characteristic for RNA-binding proteins or any other known protein domain, but it shares a striking similarity with a rat resiniferatoxin-binding protein.

Sympathetic tone restrains arterial distensibility of healthy and atherosclerotic subjects.

BACKGROUND: Sympathetic activation induced by cold pressor test or cigarette smoking is accompanied by a marked reduction of radial artery distensibility. It is not known, however, whether arterial distensibility is under tonic sympathetic restraint, or whether this restraint involves arteries greater than the radial one in both normal and pathological conditions. METHODS: We studied the distensibility of radial artery by continuous ultrasonographic assessment of the changes in arterial diameter over the diasto-systolic pressure range (finger pressure measurement) in eight patients with a Dupuytren disease before and 20 min after ipsilateral brachial plexus anaesthesia. We also studied ultrasonographic distensibility of femoral artery in seven subjects before and 20 min after ipsilateral subarachnoid anaesthesia, performed before arthroscopic surgery, and in five patients with claudicatio intermittens before and 1 month after ipsilateral removal of the lumbar sympathectomy chain. In all three conditions, the contralateral artery served as control. RESULTS: The three interventions did not cause any significant alteration in blood pressure and heart rate. Radial artery distensibility was markedly increased by ipsilateral anaesthesia of the brachial plexus (+36%, P<0.01). This was the case also for femoral artery distensibility both following ipsilateral subarachnoid anaesthesia in healthy subjects (+47%, P<0.05) or ipsilateral sympathetic gangliectomy in patients with peripheral artery disease (+26%, P<0.05). In all three instances, the distensibility of the contralateral artery remained unaffected. CONCLUSIONS: These data indicate that the sympathetic nervous system exerts a marked tonic restraint of arterial distensibility. This restraint involves medium-size and large muscular arteries and can also be seen in subjects with peripheral artery disease. This stiffening influence may increase the traumatic effect of intravascular pressure on the vessel wall and favour atherosclerosis.

Effects of prolonged immobilization of the limb on radial artery mechanical properties.

Physical training is associated with an increase in arterial distensibility. Whether the effect of training on this variable is evident also for ordinary levels of exercise or no exercise is unknown, however. We have addressed this issue by investigating the effect on radial artery distensibility of prolonged monolateral immobilization of the ipsilateral limb versus the following resumption of normal mobility. We studied 7 normotensive subjects (age, 25.4+/-3.0 years; systolic/diastolic blood pressure, 119+/-9/68+/-6 mm Hg, mean+/-SE) in whom 1 limb had been immobilized for 30 days in plaster because of a fracture of the elbow. At both the day after plaster removal and after 45 days of rehabilitation, radial artery distensibility was evaluated by an echo-tracking device (NIUS-02), which allows arterial diameter to be measured noninvasively and continuously over all pressures from diastole to systole (finger monitoring), with the distensibility values being continuously derived from the Langewouters formula. In both instances, the contralateral arm was used as control. Immediately after removal of the plaster, radial artery distensibility was markedly less in the previously immobilized and fractured limb compared with the contralateral limb (0.4+/-0.1 versus 0.8+/-0.1, 1/mm Hg 10(-3), P<0.05). After rehabilitation, the distensibility of the radial artery was markedly increased in the previously fractured limb (0.65+/-0.1 1/mm Hg 10(-3), P<0.05), whereas no change was seen in the contralateral limb. Thus, complete interruption of physical activity is associated with a marked reduction of arterial distensibility, indicating that even an ordinary level of activity plays a major role in modulation of arterial mechanical properties.

Graft-tunnel mismatch in endoscopic anterior cruciate ligament reconstruction. Intraoperative and cadaver measurement of the intra-articular graft length and the length of the patellar tendon.

The results of a study conducted on 50 knees endoscopically reconstructed for an anterior cruciate ligament (ACL) lesion with a free bone-patellar tendon-bone graft and 9 cadaver knees are reported. The mean lengths of the patellar tendon (45.48 +/- 4.71 mm) and intra-articular ACL graft (20.44 +/- 1.98 mm) were measured in the operated knees. The mean length of the tibial bone tunnel (51.62 +/- 2.60 mm) was also measured with a tibial guide at 55 degrees. No statistically significant correlation was found between these three measurements. The length of the patellar tendon was weakly correlated with body height. Measurement of the tibial tunnel on the cadaver knees with increasing degrees of inclination revealed a mean length increase of 0.68 mm per degree (confidence limits: 0.49-0.86). Comparison between the tunnel lengths obtained with the guide and those measured with a Kirschner wire showed a mean difference of 2.3 mm. It is thus desirable to make the tunnel about 53 mm long to ensure excellent fixation of a 28 mm bone block with a 25 mm interference screw. Correct measurement of the anatomical structures involved is in any event an essential requirement for proper execution of the surgical technique.

Monitoring of benzylpenicillin in ovine milk by HPLC.

A method for determination in vivo of the benzylpenicillin residues in ovine milk at low levels was described. Two groups of Sardinian breed sheep were treated with a dose of penicillin G sodium salt by intramammary infusion and intramuscular administration respectively. The residues were detected by isocratic HPLC method of the extract obtained from a previous cleanup procedure. Linear calibration plots were obtained over a large concentration range of 1 mg ml-1 -10 ng ml-1, with correlation coefficients greater than 0.998. Recoveries between 78.6 and 87.3% were obtained. Limit of detection (LOD) and limit of determination (LOQ) were 2.6 and 8.8 ng ml-1 respectively. This method would be useful for routine monitoring of penicillin G residues in ovine dairy milk.

Bone assessment after total knee arthroplasty by dual-energy X-ray absorptiometry: analysis protocol and reproducibility.

Bone quality is important for the success of joint prostheses implantation, and the assessment of bone density after total knee arthroplasty by means of dual-energy X-ray absorptiometry may be useful for monitoring implant stability. The aim of this study is to suggest a validated analysis protocol for the assessment of bone status after total knee arthroplasty. A dedicated densitometric analysis protocol of five regions of interest was designed, and 10 subjects who had received an uncemented knee prosthesis (8 females and 2 males, aged 55-74 years) underwent three consecutive scans in posteroanterior and lateral projections, with repositioning after each scan to test the suitability and reproducibility of the protocol. The reproducibility of the measurement of bone mineral content and density in the femoral and tibial regions ranged, respectively, from 2.1% to 4.1%, from 0.9% to 2.6% for the posteroanterior scans, and from 2.7% to 5.6% and from 2.3% to 4.7% for the lateral scans, depending on the considered region. Our results confirm that the suggested protocol allows precise assessment of bone mineral content and density, and that dual-energy X-ray absorptiometry is reliable for the evaluation of bone mass around prosthetic implants.