Quasifree (p, 2p) Reactions on Oxygen Isotopes: Observation of Isospin Independence of the Reduced Single-Particle Strength

Quasifree one-proton knockout reactions have been employed in inverse kinematics for a systematic study of the structure of stable and exotic oxygen isotopes at the R^{3}B/LAND setup with incident beam energies in the range of 300-450  MeV/u. The oxygen isotopic chain offers a large variation of separation energies that allows for a quantitative understanding of single-particle strength with changing isospin asymmetry. Quasifree knockout reactions provide a complementary approach to intermediate-energy one-nucleon removal reactions. Inclusive cross sections for quasifree knockout reactions of the type ^{A}O(p,2p)^{A-1}N have been determined and compared to calculations based on the eikonal reaction theory. The reduction factors for the single-particle strength with respect to the independent-particle model were obtained and compared to state-of-the-art ab initio predictions. The results do not show any significant dependence on proton-neutron asymmetry.

ACL reconstruction using bone-patella tendon-bone autograft: press-fit technique vs. interference screw fixation

PURPOSE

The gold standard in ACL reconstructions has been the bone-patellar tendon-bone autograft fixed with interference screws. This prospective, randomized clinical trial aimed to compare two methods of fixation for BPTB grafts: press-fit fixation vs. interference screw, over a 12-month follow-up interval.

METHODS

158 patients with an average age of 29.8 years, between 2011 and 2012, were treated for torn ACL. 82 patients underwent reconstruction with BPTB autograft with a press fit fixation technique, and in 76 cases an interference screw was used. At the time of final follow-up, 71 patients in press-fit group and 65 patients in interference screw group were evaluated in terms of return to pre-injury activity level, pain, knee stability, range of motion, IKDC score and complications.

RESULTS

At 12-month follow-up, 59 (83 %) and 55 (85 %) in press-fit and screw group, respectively had good-to-excellent IKDC score (p > 0.05). The mean laxity assessed using a KT-1000 arthrometer improved to 2.7 and 2.5 mm in press-fit and screw group, respectively. Regarding Lachman and pivot shift test, there was a statistically significant improvement in the integrity of the ACL in both the groups, but no significant differences was noted between groups. There were no significant differences in terms of femur circumference difference, effusion, knee range of motion, pain and complications.

CONCLUSIONS

The press-fit technique is an efficient procedure. Its outcome was comparable with the interference screw group. Furthermore it has unlimited bone-to-bone healing, no need for removal of hardware, ease for revision and cost effectiveness.

Treatment of intertrochanteric fractures in elderly highrisk patients: dynamic hip screw vs. external fixation

INTRODUCTION

Although the use of a dynamic hip screw (DHS) is considered to be the preferred treatment for intertrochanteric fractures, the external fixation device could produce clinical outcomes comparable to the outcomes obtained with conventional treatment. Furthermore, because external fixation is minimally invasive, we expected a lower rate of morbidity. Therefore, we compared the two treatments in a clinical trial of elderly patients with intertrochanteric fracture.

METHODS

60 elderly high-risk patients with an average age of 78 years were treated for intertrochanteric fracture, resulting from a low energy trauma. Patients were randomly divided in two groups regarding to treatment. In Group A the patients were treated with DHS, while in Group B were treated with external fixator.

RESULTS

The fixator was well accepted and no patient had significant difficulties while sitting or lying. The average intraoperative time was 73 min in Group A and 15 min in Group B (p<0.05). 27 patients of Group A need blood transfusion postoperatively and none in Group B (p<0.05). The mean duration of hospitalization in Group A and Group B was 8.4 and 2.2 days, respectively (p<0.05). 9 of patients Group B had pin-track infection grade 2 that all were treated by oral antibiotics. There were no differences in comorbidities, quality of reduction, screw cut out, bed sore and HHS between the two groups.

CONCLUSION

Treatment with external fixator is an effective treatment for intertrochanteric fractures in elderly highrisk patients. The advantages include quick and simple application, minimal blood loss, less radiation exposure, adequate fixation, pain reduction, early discharge from hospital, low costs and favourable functional outcomes.