Background

Accurate and reproducible radiological assessment of shoulder replacement prostheses over time is important for identifying failure or to provide reassurance. A number of clearly defined radiological parameters have been described to help standardise the radiological assessment of prostheses. To our knowledge, this is the first study conducted to test the reproducibility and reliability of these measurements.

We investigated the effect of the location and the number of distal screws in the efficiency of an intramedullary nail implementing the finite element method (FEM).

The left proximal femur of a 93-year old man was scanned and two series of full 3D models were developed. The first series, consisting of five models, concerned the use of a single distal screw inserted in five different distal locations. The second series, consisting of four models, concerned the use of four different pairs of distal screws. Each model was analyzed with the (FEM) twice, first considering that the femur is fractured and then considering that the femur is healed.

For nails with a single distal screw, stresses around the nail hole were reduced with proximal placement of the distal screw but the area around the nail hole where the lag screw is inserted is stressed more. Furthermore, for nails with a pair of distal screws, placing the pair of distal screws at a specific location is most beneficial for the mechanical behavior of the femur/nail assembly.

The distal area of the nail generally gets less stressed when a pair of distal screws is introduced, while the presence of two distal screws far away from each other results in lower proximal femoral head displacements. The stress field at the area of fracture is not influenced significantly by the presence of a single distal screw or a pair of distal screws.

The aim of the study was to investigate, firstly, the force distribution between scaphoid/radius and lunate/radius in the normal wrist and in the presence of a scaphoid fracture, secondly, how stresses and strains at the fractured area change during the healing process and thirdly, how the direction of the applied forces affects load transmission.

A 3D finite element model of the normal wrist was initially developed. Two typical scaphoid fractures B2 and B3 according to Herbert’s classification, were investigated. The fractured areas were modeled with a range of modulus of elasticity to resemble the various stages of the healing process. Furthermore, three different directions of the externally applied loads were examined.

The applied compressive vertical load in the normal joint was transmitted to the radius through the radioscaphoid and the radiolunate articular surfaces at a ratio equal to 56:46 respectively. The ratio was equal to 54:48 and 53:49 for the B2 and the B3 fracture respectively. The load direction resembling an ulnary deviated wrist caused the appearance of a significantly higher strain field at the fractured area. The maximum developed stresses at the fractured area for scaphoid fracture B2 were approximately 37%–58% higher than those of B3, for all three loading directions.

Based on our results, the onset of osteoarthritic changes in a wrist with a scaphoid fracture is due to carpal collapse and scaphoid deformity. The recorded maximum developed strains for both B2 and B3 scaphoid fractures suggested intense bone remodeling activity. Among the examined three different load directions, the one simulating an ulnary deviated wrist corresponded to the most severe effects.

To evaluate the clinical outcome of arthroscopic treatment of ACL with an Achilles tendon allograft in patient with acute rupture.

22 patients, between 2003 and 2006, with acute rupture of ACL, were treated with an Achilles tendon allograft. The mean age was 26 years. Patients were evaluated before and after surgery and at the latest follow-up with Noulis-Lahmann test and Pivot shift test. We also used IKDC score, Lysholm score and one leg stance test and functional reach test. Patients were also evaluated with Cybex II + and with plain radiographies.

The mean follow-up time was 3.5 years. 90% of the patients had a negative pivot shift test and 95% of the patients had a score at Noulis-Lahmann test +1. The mean value of IKDC score was 88 (62–100) and the mean time of Lysholm score was 91 (75–100). Until the latest follow-up there were no clinical sighs of inflammation or graft rejection. Radiologic evaluation revealed no sign of tunnel enlargement.

We believe that the use of a fresh-frozen allograft in the treatment of acute ACL ruptures is an effective procedure for the restoration of ligamentous stability of the knee.

AIM: Chronic osteomyelitis is a difficult to treat infection requiring prolonged antimicrobial therapy and involving systems of local antimicrobial delivery. Linezolid is a new antimicrobial agent with well documented in vitro activity against gram positive cocci when resistance to other antistaphylococcal agents is present. Few data are present regarding its embedding in local antimicrobial delivery systems and subsequent elution. The elution of linezolid by a polylactic acid (PLA) system was studied.

METHODS: Linezolid was dry-mixed with PLA at a ratio of 1:9, ie 50mg of linezolid were mixed with 450mg PLA. The mixture was diluted with 0,5mL of methanol and placed at the bottom of a cylindrical vial. Two replicas were created and one mL of Mueller-Hinton broth was added over the free solid surface of each mixture. Vials were transferred to a 37°C incubator and broth was replaced every 48h for 11 days. Concentration of linezolid was determined by an HPLC method using a Zorbax Eclipse XDB-C8 column and UV detection.

RESULTS: Mean linezolid concentration at days 1, 3, 5, 7, 9 and 11 was 2778.54 mg/L, 2456.22 mg/L, 668.63 mg/L, 324.86 mg/L, 390.10 mg/L, and 155.28 mg/L respectively.

CONCLUSION: Elution of linezolid by a PLA local delivery system remains very high throughout the period studied. The results are promising for the therapy of staphylococcal chronic osteomyelitis with the use of a PLA local antimicrobial delivery system employing linezolid.

Aim: To compare two implants, the Gamma Nail and the ACE Trochanteric Nail in the treatment of pertrochanteric femoral fractures.

Patients and methods: Sixty patients were randomized on admission to two treatment groups. Thirty patients were treated with the Gamma nail implants , and thirty had intramedullary fixation with ACE Trochanteric NailI . The average age of these patients was 79 years. 22 patients were men and 38 women. 11 fractures were stable and 49 unstable. Patients were followed for 1 year and had a regular clinical and radiological review at 1, 3 and 6 months postoperatively. Operation time, intra-operative blood loss and blood transfusion and complications were recorded. The mobility score was used to assess the preinjury and postoperative mobility status. All the patients were operated within 24 hours after their accident and 39 of them within the first 6 hours.

Results: There were no complications during the surgery. All the patients were mobilized the first 24 hours post operatively irrespectively of the fracture’s type, and weight bearing was permitted as tolerated. The mean follow up time was 8 months (range 6 to 12 months). 3 patients were lost at the follow up and 2 died. Union of the fracture was achieved in all 55 patients. There was no statistically significant difference between the two groups with regard to intraoperative blood loss and the duration of the surgery. There was no mechanical failure of the implants despite the early patients mobilization. All the patients achieved mobility status similar to the preoperative at the latest follow up.

Conclusions: Based on our study, intramedullary nailing of pertrochanteric hip fractures represents a reliable method of treatment. We did not observe any differences in the two patient groups concerning the operation time, the intraoperative blood loss, the postoperative complications and the patients functional status at the latest follow up.