Introduction and Objective

Kinematic Alignment (KA) is a surgical technique that restores the native knee alignment following Total Knee Arthroplasty (TKA). The association of this technique with a medial pivot implant design (MP) attempts to reestablish the physiological kinematics of the knee. Aim of this study is to analyze the clinical and radiological outcomes of patients undergoing MP-TKA with kinematic alignment, and to assess the effect of the limb alignment and the orientation of the tibial component on the clinical outcomes.

PURPOSE OF THE STUDY: We reported of eleven cases of early spontaneous osteonecrosis (SO) of the knee successfully treated with an extracorporeal shock-wave treatment (ESWT).

Traumatic and vascular theories have been proposed as the cause of the SO, lack of blood in some critical areas, such as subchondral bone of femoral condyles or tibial plateaus, has been considered the underlying condition of this pathology.

ESWT can be suggested as an effective conservative treatment for SO of the knee.

MATERIALS AND METHODS: Ten patients with medial femoral condyle osteonecrosis of the knee (one bilateral) were evaluated. Exclusion criteria was evidence of a structural collapse of subchondral bone. Two patients had received a femoro-popliteal by-pass within the last year, while others five presented a deficit of the vascular axis of the homolateral lower limb documented by an eco-colordoppler. A clinical evaluation was taken at the diagnosis using KSS, PPI, NRS and VAS. Plain radiographs and MRI confirmed the diagnosis of osteonecrosis.

Patients were treated with a cycle of three ESWT performed with 2000 pulses of 0,28 mJ/mm2 with Wolf Piezoson 300 with 6,5 MHz ultrasounds for three times in a month.

Clinical evaluation was performed at first and at third month after treatment and a MRI evaluation was performed at fourth month after treatment.

RESULTS: Clinical evaluation showed a significant improvement of symptoms and articular functionality. MRI of all cases revealed the continuity of the cartilage with a reduction in bone marrow edema and no collapse of lesion.

DISCUSSION: In our study, a single cycle of ESWT produced an improvement of the clinical and MRI aspects in eleven cases of SO of the knee. The neo-angiogenetic effect of the ESWT appears to accelerate the time for the symptom remission.

ESWT might have the potential to avoid the need for surgical treatment.

Introduction: The purpose of this work is to create an in vitro model of engineered osteochondral composite by combining a cylinder of calcium phosphate and cartilage tissue produced by isolated swine articular chondrocytes seeded onto fibrin glue.

Methods: Swine articular chondrocytes were enzimatically isolated and seeded onto fibrin glue. Immediately before gel polymerization, the fibrin glue was placed in contact with the cylinders of calcium phosphate. The osteochondral composites were left in standard culture conditions for 1,3,6 weeks. At the end of experimental times the samples were macroscopically analysed and processed for histological evaluation.

Results: Preliminary data showed a macroscopically integrity of the osteochondral samples. Histology showed cartilage like tissue maturing within the fibrin glue scaffold.

Discussion: The results demonstrate that isolated chondrocytes, seeded onto fibrin glue, produce a cartilage-like matrix that integrates with a cylinder of calcium phosphate.

This tissue engineered osteochondral composite could represent a valuable model for further in vivo studies on the repair of osteochondral lesions.

Objective: The purpose of this study is to evaluate the functional performance of patients who underwent to two different types of total knee prosthesis replacement (TKR).

Methods: Kinematics and kinetics of the knee and ankle and electromyography activity of the lower limb muscles were obtained from 16 patients who underwent a TKR. 8 patients had received a fixed bearing prosthesis while the other 8 patients had received a mobile bearing prosthesis. The functional performance of the patients was evaluated using two tests, the gait and the squat. As control, 8 normal subjects, matched by age, were also evaluated.

Results: During the stance phase of gait, patients with TKR showed a reduced knee extensor (internal) moment as compared to normal controls. During the squat test, patients with TKR exhibited a knee ROM that was reduced with respect to normal patients. Moreover, all patients with TKR showed a low velocity of execution of the both tests. There were no significant differences between patients who had received a fixed vs. mobile bearing prosthesis.

Discussion: The results showed that after TKR, the functional performance of the patients is different from that of the normal subjects, regardless of the type of prosthesis implanted.

In the past the prevailing view believed that there was an inverse relationship between osteoarthritis and osteoporosis; a recent study showed that elderly women with advanced osteoarthritis requiring total hip replacement had an evidence of osteoporosis and vitamin-D deficiency. An altered metabolic bone status as induced by low level of vitamin D could be one of the major causes of aseptic bone loosening and consequently failure of the implant. We studied the bone mineral metabolism of thirty elderly women with osteoarthritis undergoing total hip replacement in order to identify whether or not there were a bone metabolic alterations.

All the subjects included in the study were over than 70 years old (mean age 74 ± 2.5). The results showed that six (20%) subjects had a hypovitaminosis D status and eighteen (60%) had a vitamin D deficiency status. Five subjects (16%) had a secondary iperparathyroidism. The bone mineral metabolism of elderly women with osteoarthritis undergoing total hip replacement is characterised by a high prevalence of vitamin D deficiency and in a less percentage of the cases by a secondary iperparathyroidism. Both of these metabolic conditions could compromise the bone integration of the implant and lead to aseptic bone loosening.

The purpose of this work was to create an in vitro model of tissue-engineered cartilage structure produced by isolated swine articular chondrocytes, expanded in culture and seeded onto a biological scaffold.

Swine articular chondrocytes were enzymatically isolated from pig joints and expanded in monolayer culture. When confluence was reached, cells were resuspended and seeded in vitro onto biological collagen scaffolds for 3, 4 and 6 weeks. Samples were retrieved from the culture and analysed macroscopically and biomechanically by compressive test. Gross evaluation was performed by simple probing, sizing and weighing the samples at all time periods. A baseline of the values was also recorded at time 0. Then, samples were biomechanically tested by unconfined compression and shear tests. Finally, the samples were fixed in 4% paraformaldehyde and processed for histological evaluation. Some samples were stained with Safranin-o, and some others subjected to immunostaining analysis for type II collagen.

Upon retrieval, samples showed dimensional enlargement and mass increase over time and gross mechanic integrity by simple probing. A biomechanical test demonstrated an initial reduction in the values of compressive and shear parameters, followed by a consistent increase throughout the tested time points. Histology showed cartilage-like tissue maturing over time within the biological scaffold.

The results from this study demonstrate that isolated chondrocytes could be seeded onto a biological collagen scaffold, producing cartilage-like matrix with tissue-specific morphology and biomechanical integrity. This tissue-engineered cartilage structure is easily reproducible and it could represent a valuable model for studying the behaviour of different variables on the newly formed cartilage.