Mechanical loading of joints with osteoarthritis (OA) results in pain-related functional impairment, altered joint mechanics and physiological nociceptor interactions leading to an experience of pain. However, the current tools to measure this are largely patient reported subjective impressions of a nociceptive impact. A direct measure of nociception may offer a more objective indicator. Specifically, movement-induced physiological responses to nociception may offer a useful way to monitor knee OA. In this study, we gathered preliminary data on healthy volunteers to analyse whether integrated biomechanical and physiological sensor datasets could display linked and quantifiable information to a nociceptive stimulus.

Following ethical approval, 15 healthy volunteers completed 5 movement and stationary activities in 2 conditions; a control setting and then repeated with an applied quantified thermal pain stimulus to their right knee. An inertial measurement unit (IMU) and an electromyography (EMG) lower body marker set were tested and integrated with ground reaction force (GRF) data collection. Galvanic skin response electrodes for skin temperature and conductivity and photoplethysmography (PPG) sensors were manually timestamped to the integrated system.

Pilot data showed EMG, GRF and IMU fluctuations within 0.5 seconds of each other in response to a thermal trigger. Preliminary analysis on the 15 participants tested has shown skin conductance, PPG, EMG, GRFs, joint angles and kinematics with varying increases and fluctuations during the thermal condition in comparison to the control condition.

Preliminary results suggest physiological and biomechanical data outputs can be linked and identified in response to a defined nociceptive stimulus. Study data is currently founded on healthy volunteers as a proof-of-concept. Further exploratory statistical and sensor readout pattern analysis, alongside early and late-stage OA patient data collection, can provide the information for potential development of wearable nociceptive sensors to measure disease progression and treatment effectiveness.

Prosthetic joint infections (PJI) occur infrequently, but they represent the most devastating complication with high morbidity and substantial cost. Staphylococcus aureus are the most common infecting agents associated with acute PJI, and also appear in some cases of delayed PJI¹. S. aureus biofilm development can be divided in two stages: adhesion and proliferation². To avoid PJI bacterial adhesion has to be decreased.

Hybrid organo-inorganic sol-gel coatings are proposed as a promising biomaterial improvement³. One of these compounds is a mixture of two organopolisiloxanes: 3-methacryloxypropyltrimethoxysilane (MAPTMS) and tetramethylorthosilicate (TMOS). The aim of this work was to evaluate bacterial adhesion on MAPTMS-TMOS coating compared to titanium parts made by powder metallurgy.

MAPTMS-TMOS sol-gel coating was produced using a molar ratio of 1:2 (MAPTMS:TMOS) and dispersed in ethanol. The sol-gel was deposited by dip-coating on titanium parts made by powder metallurgy followed by a thermal treatment at 120 ºC for 30 minutes⁴. Titanium parts without sol-gel coating were used as control.

S. aureus 15981 strain adherence study was performed using the protocol described by Kinnari et al.⁵ with 90 min incubation. After incubation, the samples were stained with LIVE/DEAD BacLight Bacterial Viability Kit. Proportion of total adhered, live and dead bacteria was calculated and studied by using ImageJ software. The experiments were performed in triplicate.

The statistical data were analyzed by pairwise comparisons using the nonparametric Mann-Whitney test with a level of statistical significance of p<0.05. Values are cited and represented as medians.

S. aureus 15981 adherence was 942-fold lower on MAPTMS-TMOS coating than on uncoated titanium.

According with our results, MAPTMS-TMOS sol-gel coating is a promising antiadherent surface for S. aureus. More studies are necessary in order to evaluate this property with other species and strains.

Material-based strategies seek to engineer synthetic microenvironments that mimic the characteristics of physiological extracellular matrices for applications in regenerative therapies, including bone repair and regeneration. In our group, we identified a specific chemistry, poly(ethyl acrylate) (PEA), able to induce the organization of fibronectin (FN), upon adsorption of the protein, into fibrillar networks similar to the physiological ones, leading to enhanced cellular response, in terms of cell adhesion and differentiation. In this work, we exploit these FN networks to capture and present growth factors (GF) in combination with the integrin binding domain of FN during bone tissue healing.

Fibrillar conformation of FN adsorbed on PEA favors the simultaneous availability of the GF binding domain (FNIII12–14) next to the integrin binding region (FNIII9–10), compared to poly(methyl acrylate) (PMA), a material with similar chemistry, where FN adopts a globular conformation. The combined exposure of specific adhesive sequences recognized by integrins and GF binding domains was found to improve the osteogenic differentiation of mesenchymal stem cells. A higher expression of bone proteins was found when BMP2 is bound or sequestered on the material surface versus its administration in the culture media in vitro. The potential of this system as recruiter of GFs was also investigated in a critical-size bone segmental defect in mouse. The synergistic integrin-GF signalling, induced by fibrillar FN, promoted bone formation in vivo with lower BMP2 doses than current technologies. Furthermore, we optimized the system for its potential use in translational research, seeking to address the clinical need of using biocompatible and biodegradable material implants. Polycaprolactone scaffolds were synthesized and coated with a thin layer of plasma- polymerized PEA that recruits and efficiently presents GF during healing of critical size defects.

The material-driven FN fibrillogenesis provides a new strategy to efficiently reduce the GF doses administrated in bone regenerative therapies.

AIM: The scaphoid resection with four-corner fusion is an effective procedure for treatment of postraumatic and degenerative wrist osteoarthritis. Few studies that evaluated the functional and workers compensation results are available in the literature. We presented the results of 4-corner fusion on active heavy labour workers.

MATERIAL AND METHODS: A prospective study to evaluate 38 patients (37 male and 1 female) who underwent 4-corner fusion, between 2002 to 2005, with an average of 24 months of follow-up (range, 12–48 months) were made. The mean age of the patients were 32 years (range, 25–48 years). All patients were heavy-labour workers. The aethiology in 77% of the patients was SNAC wrist. Dominant limb was involved in 65% of the patients. All patients were immobilised in a cast for 4 weeks after surgery. Patients were assessed clinically and radiographically. Functional analysis of grip and pinch strenght were performed.

RESULTS: Consolidation was obtained in all cases at 10 weeks. Pain evaluation score was 77 at pre-op and 19 on post-op time. The range of flexion – extension movement postoperative was 57°. Average lost of pinch strength was 25%. All patients return to work, 80% to the same activity level and 20% to a different work performing less strenuous activities. After surgery, the range time to return to work was 160 days.

CONCLUSION: The four-corner fusion allows an effective stabilization, maintaining the bone stock and eliminate wrist pain. This technique permit a fast return to work with a great level of satisfaction and preserve a functional range of motion with a minimum lost of force in heavy labour workers.

Hip resurfacing is a procedure designed to conserve bone stock in the younger patient and facilitate revision to a total hip arthroplasty if the need arises. The Wagner Hip Resurfacing (WHR) was a metal-on- poly implant introduced in 1978.

The notes and radiographs of 16 patients who underwent 19 WHR procedures performed by a single surgeon between 1980 and 1984 were reviewed.

The mean age at primary surgery was 54 (range 41–68). 16 of the WHRs required revision at a mean time of 45 months (range 1–144 months). 3 WHR had not been revised: one is functioning at 22 years, one functioning well 20 years after implantation when the patient died and 1 non-functional 9 years after implantation due to femoral head reabsorption.

The reason for revision was femoral neck fracture (3), femoral head collapse / avascular necrosis or loosening (8), acetabular loosening (5).

Subsequent problems with the revision were noted in 6 patients (2 dislocations, 2 infections, 1 acetabular loosening and 1 femoral loosening). 3 patients ended with a Girdlestone excision arthroplasty and 2 required re-revision.

Hip resurfacing is designed as a conservative option for the young arthritic hip. This prosthesis not only failed catastrophically at an early stage but had a major subsequent impact on revision surgery and complications associated with it.