A. Bistolfi

Dislocation rate after hip arthroplasty within the first postoperative year: 36 mm versus 28 mm femoral heads.

Dislocation is a common and important complication of total hip arthroplasty (THA). Larger femoral heads may reduce the risk of dislocation and improve the range of movement. The aim of this study was to compare the relative risk (RR) of dislocation during the first year after THA between implants with 28mm and 36mm femoral heads. 198 consecutive hips with 28mm femoral head (Group-28) and 259 hips with 36mm femoral head (Group-36) were studied. The patients were assessed preoperatively and periodically using the Harris hip score (HHS) and radiographic analysis. The relative risk (RR) of dislocation was calculated. The average HHS significantly improved from a preoperative baseline to the last follow-up at 82.1 months (28mm) and 44.3 months (36mm). No statistically significant differences were revealed between the two groups for HHS results and complications (p>0.05), but the difference in RR of dislocation within the first year between the two groups was 7.85 (95%CI: 1.34–46.03), p=0.046. Although dislocation is multifactorial in etiology, the two groups were homogenous for all principal contributing factors except the diameter of the femoral head. Therefore, the use of 36-mm heads can reduce the risk of dislocation following THA by a factor of 8 compared to conventional 28mm heads.

Interplay between surface properties of standard, vitamin E blended and oxidised ultra high molecular weight polyethylene used in total joint replacement and adhesion of Staphylococcus aureus and Escherichia coli

We have assessed the different adhesive properties of some of the most common bacteria associated with periprosthetic joint infection on various types of ultra high molecular Weight Polyethylene (UHMWPE). Quantitative in vitro analysis of the adhesion of biofilm producing strains of Staphylococcus aureus and Escherichia coli to physically and chemically characterised standard UHMWPE (PE), vitamin E blended UHMWPE (VE-PE) and oxidised UHMWPE (OX-PE) was performed using a sonication protocol. A significant decreased bacterial adhesion was registered for both strains on VE-PE, in comparison with that observed on PE, within 48 hours of observation (S. aureus p = 0.024 and E. coli p = 0.008). Since Vitamin E reduces bacterial adhesive ability, VE-stabilised UHMWPE could be valuable in joint replacement by presenting excellent mechanical properties, while reducing bacterial adhesiveness.

Primary stability of a PGLA/Polydioxanone membrane for potential autologous chondrocyte implantation in the hip joint. A cadaveric study

The purpose of this cadaveric study was to evaluate the primary stability of a membrane (resorbable polyglactin-910/poly-p-dioxanone) for autologous chondrocyte implantation (ACI) inserted by press-fit into defects in the femoral head and acetabulum. The stability of the membrane was evaluated after implantation in a cartilage defect on both sides of the joint in 12 hips in six cadavers. The hip was manually put through a full range of motion for 50 cycles after each lesion had been created and filled, starting with the acetabulum. The implanted membranes showed stability in 83.3% of the acetabular defects and in 33.3% of the femoral defects after the 50 cycles. After an additional 50 cycles the acetabular membrane showed stability in a total of eight (67%) out of 12 acetabular lesions. The results indicate that this membrane tissue is potentially stable in cartilage defects of the acetabulum, which may have clinical applications in autologous chondrocyte implantation.

Therapeutic Ultrasound in Physical Medicine and Rehabilitation: Characterization and Assessment of Its Physical Effects on Joint-Mimicking Phantoms

The aim of the study described here was to quantitatively assess thermal and mechanical effects of therapeutic ultrasound (US) by sonicating a joint-mimicking phantom, made of muscle-equivalent material, using clinical US equipment. The phantom contains two bone disks simulating a deep joint (treated at 1 MHz) and a superficial joint (3 MHz). Thermal probes were inserted in fixed positions. To test the mechanical (cavitational) effects, we used a latex balloon filled with oxygen-loaded nanobubbles; the dimensions of the oxygen-loaded nanobubbles were determined before and after sonication. Significant increases in temperature (up to 17°C) with fixed field using continuous waves were detected both in front of and behind the bones, depending on the US mode (continuous wave vs. pulsed wave) and on the treatment modality (fixed vs. massage). We found no significant differences in mechanical effects. Although limited by the in vitro design (no blood perfusion, no metabolic compensation), the results can be used to guide operators in their choice of the best US treatment modality for a specific joint.

Personalized Therapeutic Ultrasound in Shoulder Disease: MultimodalAssessment and Results

Introduction: Therapeutic ultrasound (US) has been used in physiotherapy for more than 50 years to treat acute and chronic inflammatory diseases in joints, muscles, tendons, ligaments and so on. Despite of its widespread use in rehabilitative practice and the large number of studies, low scientific, statistically assessed evidences of therapeutic US effectiveness are available. As a matter of fact, details about the treatment modalities and the way in which the patients’ feedback was collected are often missing. The aim of our study is to assess the therapeutic US effectiveness in shoulder disease management when a “customized” treatment to each patient is delivered and the clinical outcome is globally monitored. Methods: Patients with shoulder pain who underwent rehabilitative treatment, including Ultrasound Therapy (US) in our Department of Physical Therapy and Rehabilitation Medicine at Turin University from May to September 2015 were enrolled. Clinical, functional and sonographycal evaluation of the shoulder was performed before US treatment (T0), and at the end of the US therapy (T1) using Numeric Rating Scale, Constant Score, DASH questionnaire and sonography. Results: Statistically relevant improvements of the clinical outcome were observed in all the considered parameters, with a significant reduction of shoulder pain and functional limitation in all patients. Sonographic images support clinical data. Conclusions: Although studies involving a larger number of patients are required, the effectiveness of ‘customized’ US treatment evaluated with different approaches, including sonography, is assessable and lead to statistically significant results.

Incontinentia pigmenti: a rare pathology with complex rehabilitative aspects

Abstract Purpose: Incontinentia pigmenti (IP), or Bloch-Sulzberger syndrome, is a rare X-linked dominant genetic disorder with multisystem involvement. To our knowledge, there are no previous reports about rehabilitation in IP adult with intact cognitive development. We report a 20-year-old lady with IP managed and followed into adulthood. Method: Patient management and rehabilitation programs from birth to the last follow-up. Results: There was normal cognitive development despite magnetic resonance imaging (MRI) evidence of white matter, corpus callosum and brainstem hypoplasia. Extensor spasticity was present on both lower limbs for which she underwent rehabilitation from the age of one. Botulinum toxin injections were performed and when she was 15 years old she underwent functional surgery. Conclusion: The absence of mental retardation in our patient enabled us to carry out an active rehabilitation program and provide her with maximum independence in locomotion and in activities of daily living. Implications for Rehabiliation Incontinentia pigmenti (Bloch-Sulzberger syndrome). Incontinentia pigmenti is a rare X-linked dominant genetic disorder with multisystemic involvement. Skin lesions, neurological impairments, motormental retardation, skeletal congenital defects and ophthalmologic involvement are IP most frequent manifestations. Due to the complex multisystem involvement resulting in severe long-term disability, patients with IP require a multidisciplinary team approach for rehabilitation. In IP patients, rehabilitation interventions should always take into consideration the individual phenotype expression, child’s physical development and personal needs.

Ultra high molecular weight polyethylene is cytotoxic and causes oxidative stress, even when modified

Ultra High Molecular Weight (UHMW) Polyethylene (PE) is the most used biomaterial for articulating surface of total joint replacements (TJR). Since its introduction decades ago, many efforts have been made to improve its properties and to understand its behaviour with the final goal to provide a longer duration of the implants. Mechanical abrasion with particles production is an unavoidable process, but catastrophic PE wear with a huge quantity of PE reactive debris production was observed in the last years, with consequent severe periprosthetic osteolysis and aseptic loosenings. Now it is well known that the severe PE particle disease is due to UHMWPE oxidative degradation caused by a ysterilization in air (1-4). In order to solve this problem, the evolution of the conventional UHMWPE drove to alternative sterilization methods (ethylene oxide and gas plasma) and to the development of new PE derivatives with a supposed increased resistance to abrasion in vivo, such as the crosslinked PE (X-PE) and the vitamin Estabilized PE (E-PE), Unfortunately, particle disease and periprosthetic osteolysis still remain an unsolved problem (5-9). The osteolysis is an inflammatory process caused by a foreign body (10), wherein the particles trigger monocyte recruitment and macrophage activation, leading to chronic inflammation, with release of cytokines and proteases, and bone reabsorption (8). It is well recognized that PE particles induce different reactions according to dimension (fragments larger than 10 J.1m produce foreign body-induced giant cell granuloma, whereas smaller fragments are phagocytized), number, shape, superficial hydrophobicity and oxidation (11-14). The majority of the studies have been focused on how conventional and new PEs develop debris particles different in sizes and behaviours, reacting in different ways with human cells and conducting to unpredictable clinical results (7, 15-17). But beside the shape and the dimension of a PE particle, the chemico-physical properties of its surface might playa fundamental role in stimulating the inflammatory reaction, the cytotoxicity and the apoptosis. In particular, it has been suggested that PE particles per se do not cause any response although macrophages are activated, probably due to the superficial characteristics of PE and macrophage binding receptors. Different approaches have shown that some markers of inflammation and oxidative stress were induced after exposure to UHMWPE, in particular to their debris: among them, lactate dehydrogenase (LDH) release and lipid peroxidation (19) and cytokines production (20) have been observed. The mechanisms by which these events occur are not still well elucidated. Some authors demonstrated that in particular the oxidized UHMWPE is toxic in different cellular models: Reno et al. (21) showed that oxidized UHMWPE reduced proliferation in human fibroblasts and induced a strong release of gelatinase B (matrix metalloproteinase 2, MMP-2), and the surface oxidation of UHMWPE has been correlated to increased apoptosis and necrosis in human granulocytes (22). Moreover, the oxidation of UHMWPE has been strongly related to the development of inflammation around the implants (23) and Fiorito et al. (24) demonstrated that, in this inflammatory status, the production of reactive oxygen species (ROS) by inflamed synovial cells plays a very crucial role. The supplementation ofX-PE and E-PE hasbeen shown

Does metal porosity affect metal ion release in blood and urine following total hip arthroplasty? A short term study

Introduction: The surface area of exposed metal in a trabecular-titanium acetabular component is wider compared to traditional-titanium implants. The purpose of this study is to establish if this increase in surface area can lead to a significant increase in systemic metal levels. Methods: 19 patients with conventional acetabular component and 19 with trabecular-titanium cup were compared. Aluminum, Vanadium and Titanium in blood and urine were assessed before surgery and at intervals for 2 years. The samples were analysed using an inductively coupled plasma mass spectrometry. Results: Patients with trabecular-titanium did not have significantly higher metal ion levels compared to patients with conventional cups up to 2 years. A trend over time was statistically significant in both blood and urine for aluminum and titanium concentrations. Conclusions: The three-dimensionality and the wide surface of the trabecular-titanium acetabular component did not affect metal ion release compared to traditional implants after 2 years.

Unexpected Listeria monocytogenes detection with a dithiothreitol-based device during an aseptic hip revision

Prosthetic joint infection diagnosis is often difficult since biofilm-embedded microorganisms attach well to the prosthetic surfaces and resist their detection by conventional methods. DL-dithiothreitol has been described as a valid method for biofilm detachment on orthopedic devices. We report the case of an occasional detection of Listeria monocytogenes in a non immuno-compromised patient with a preoperative diagnosis of aseptic loosening. The infection diagnosis due to such rare bacteria was made postoperatively, thanks to a DL-dithiothreitol-based device. This may be considered a feasible approach for the microbiological analysis of prosthetic joint infection, considering that a prompt diagnosis of such biofilm-associated infections could bring some advantages, such as an early and appropriate antibiotic therapy administration and a reduction of undiagnosed infections.

Are we failing in hip protrusio treatment

In a recent article published in Clinical Orthopaedics and Related Research, Hanke and colleagues (1) reported the longest follow up trial available in the literature about the survivorship of hips with protrusio acetabuli treated with circumferential acetabular trimming through surgical hip dislocation. This group of patients was compared with a group of pincer type femoroacetabular impingement (FAI) without severe overcoverage. Severe pincer impingement (protrusio acetabuli) is an established cause of hip pain and osteoarthritis (OA): the acetabular roof is negatively tilted and typically deep with relative global overcoverage of the femoral head that overlaps the ilioischial line medially and protrudes in the true pelvis; therefore the size of the lunate surface is increased and leads to a pincer type FAI. Safe surgical hip dislocation described by Ganz et al .(2) with circumferential rim trimming and labral refixation or reconstruction is the current gold standard treatment for this acetabular morphology. Unfortunately this study underlines a poor expectation of survival in half of the hips with protrusio acetabuli compared with the control group according to Kaplan and Meier method’s endpoints (1): conversion to total hip arthroplasty (THA), radiographic progression of osteoarthritis, and Merle d’Aubigne-Postel score less than 15 points.