Invasive intraneural electrodes implanted in peripheral nerves are neural prosthetic devices that are exploied to control advanced neural-interfaced prostheses in human amputees. One of the main issues to be faced in chronic implants is represented by the gradual loss of functionality of such intraneural interfaces due to an electrical impedance increase caused by the progressive formation of a fibrotic capsule around the electrodes, which is originally due to a nonspecific inflammatory response called
Aim of the study: The aim of this study was to explore whether adverse reactions would occur during the material’s degradation period even at a later time point after fracture healing had been completed, in metacarpal fractures treated with third generation bioabsorbable implants. Materials and Methods: 12 unstable, displaced metacarpal fractures in 10 consecutive patients (7 males, 3 females; mean age 36.4 y, range 18–75 y) were treated with third generation absorbable plates and screws (Inion. ®. OTPSTM Biodegradable Mini Plating System), where resorption is supposed to occur within 2 to 4 years. 9 patients (10 fractures) were available for follow-up (mean 25.6 months, range 14 to 44 m) and were examined both clinically and radiologically. For patients without appearance of
The aim of this study was to explore whether adverse reactions would occur during the material’s degradation period even at a later time point after surgery and whether these phenomena were clinically significant and would influence the final outcome. 12 unstable, displaced metacarpal fractures in 10 patients (7 males, 3 females; mean age 36.4 y, range 18–75 y) were treated with the Inion. ®. OTPSTM Biodegradable Mini Plating System. 9 patients (10 fractures) were available for follow-up (mean 25.6 months, range 14 to 44 m). For patients without appearance of
A patient in his thirties developed synovitis with grade 4 chondrolysis and a stiff knee with a fixed flexion deformity between three and six years following PLC and PCL reconstruction using LARS (Ligament Augmentation and Reconstruction System, Corin). There was histologic evidence of
Intraneural electrodes can be harnessed to control neural prosthetic devices in human amputees. However, in chronic implants we witness a gradual loss of device functionality and electrode isolation due to a nonspecific inflammatory response to the implanted material, called
Our aim was to compare polylevolactic acid screws
with titanium screws when used for fixation of the distal tibiofibular
syndesmosis at mid-term follow-up. A total of 168 patients, with
a mean age of 38.5 years (18 to 72) who were randomly allocated
to receive either polylevolactic acid (n = 86) or metallic (n =
82) screws were included. The Baird scoring system was used to assess
the overall satisfaction and functional recovery post-operatively.
The demographic details and characteristics of the injury were similar
in the two groups. The mean follow-up was 55.8 months (48 to 66).
The Baird scores were similar in the two groups at the final follow-up.
Patients in the polylevolactic acid group had a greater mean dorsiflexion
(p = 0.011) and plantar-flexion of the injured ankles (p <
0.001).
In the same group, 18 patients had a mild and eight patients had
a moderate
The Masquelet technique is a variable method for treating critical-sized bone defects, but there is a need to develop a technique for promoting bone regeneration. In recent studies of bone fracture healing promotion, macrophage-mesenchymal stem cell (MSC) cross-talk has drawn attention. This study aimed to investigate macrophage expression in the induced membrane (IM) of the Masquelet technique using a mouse critical-sized bone defect model. The study involved a 3-mm bone defect created in the femur of mice and fixed with a mouse locking plate. The Masquelet (M) group, in which a spacer was inserted, and the Control (C) group, in which the defect was left intact, were established. Additionally, a spacer was inserted under the fascia of the back (B group) to form a membrane due to the
Question: Is the histopathological response of the peri-prosthetic tissue to metal-on-metal bearings comparable to the well studied reactions to polyethylene debris or do specific reactions exist and are theses reactions depending on the implant design?. Methods: Periprosthetic tissue samples from 19 THR and Hip Resurfacings (11 Birmingham Hip Resurfacings, 2 (historical)McMinn Hybrid Hip Resurfacings, 5 MetaSUL THR) with a variety of failure mechanisms were examined histopathologically and immunohistochemically. Results: Only the samples of the (historical) McMinn Hybrid resurfacings showed a stronger histiocytic
Recent researches indicate that both M1 and M2 macrophages play vital roles in tissue repair and
Reducing wear of endoprosthetic implants is still an important goal in order to increase the life time of the implant. Endoprosthesis failure can be caused by many different mechanisms, such as abrasive wear, corrosion, fretting or
For chondral damage in younger patients, surgical best practice is microfracture, which involves drilling into the bone to liberate the bone marrow. This leads to a mechanically inferior fibrocartilage formed over the defect as opposed to the desired hyaline cartilage that properly withstands joint loading. While some devices have been developed to aid microfracture and enable its use in larger defects, fibrocartilage is still produced and there is no clear clinical improvement over microfracture alone in the long term. Our goal is to develop 3D printed devices, which surgeons can implant with a minimally invasive technique. The scaffolds should match the functional properties of cartilage and expose endogenous marrow cells to suitable mechanobiological stimuli in-situ, in order to promote healing of articular cartilage lesions before they progress to osteoarthritis, and rapidly restore joint health and mobility. Importantly, scaffolds should direct a physiological host reaction, instead of a
Screw fixation is an established method for anterior cruciate ligament (ACL) reconstruction, although with a high rate of implant-related complications. An allograft system for implant fixation in ACL reconstruction, the Shark Screw ACL (surgebright GmbH) could overcome some of the shortcomings of bioabsorbable screws, such as
Menisci are crucial structures for knee homeostasis: they provide increase of congruence between the articular surfaces of the distal femur and tibial plateau, bear loading, shock absorption, lubrication, and proprioception. After a meniscal lesion, the golden rule, now, is to save as much meniscus as possible: only the meniscus tissue which is identified as unrepairable should be excised and meniscal sutures find more and more indications. Several different methods have been proposed to improve meniscal healing. They include very basic techniques, such as needling, abrasion, trephination and gluing, or more complex methods, such as synovial flaps, meniscal wrapping, or the application of fibrin clots. Basic research of meniscal substitutes has also become very active in the last decades. The features needed for a meniscal scaffold are: promotion of cell migration, it should be biomimetic and biocompatible, it should resist forces applied and transmitted by the knee, it should slowly biodegrade and should be easy to handle and implant. Several materials have been tested, that can be divided into synthetic and biological. The first have the advantage to be manufactured with the desired shapes and sizes and with precise porosity dimension and biomechanical characteristics. To date, the most common polymers are polylactic acid (PGA); poly-(L)-lactic acid (PLLA); poly- (lactic-co-glycolic acid) (PLGA); polyurethane (PU); polyester carbon and polycaprolactone (PCL). The possible complications, more common in synthetic than natural polymers are poor cell adhesion and the possibility of developing a
Millions of medical devices made of synthetic or modified natural materials all trigger a similar reaction—the
Aims: Fracture repair with biodegradable implants (BDI) avoids implant removal, associated with improved patientñs beneþt and reduced health cost. However,
Introduction Rotator cuff degeneration is considered to be a major factor in the pathogenesis of rotator cuff tendon tear. Degenerative weakening of the rotator cuff can result in irreversible complete cuff-tear arthropathy syndrome. Recently a porcine small intestinal submucosa (SIS) has been approved by TGA as biological implant for the repair of rotator cuff tendon tear. The aims of this study are to evaluate the safety and efficacy of SIS. Methods A commercial brand of SIS was examined by histology and PCR technique. The material was implanted into mice and rabbits for the evaluation of biological reaction and inflammatory response. Next, we have used SIS to replace the rotator cuff tendon in rabbit (N=10) and compared to control (N=10). Histological examination was conducted at four and eight weeks after implantation. To further confirm if cells present in SIS material were of porcine origin, nested PCR for the amplification of DAP12 gene was used. Results Fresh SIS membrane before implantation contain multiple layers of spindle-shaped cells mixed with a small population of round-shaped cells. Chloroacetate esterase staining showed that the round-shaped cells are positive, indicating that they are mast cells. The tissue architecture of SIS mimics tendon structure as evidenced by H &
E staining. The SIS membrane contained porcine DNA materials. Subcutaneous implant of SIS in mice (by six) for up to seven days showed no obvious inflammatory response or
[Introduction]. In 1995, Muller reported on the improvement of metal-on-metal (MOM) bearing over the existing metal-on-polyethylene (MOP) articulations which demonstrated more rapid wear together with granulomatous
Introduction: Hip simulator tests, analyses of retrieved components as well as radiostereometric measurements revealed that cups made of highly linked polyethylene show a much better wear performance than cups of conventional polyethylene. However, to the best of our knowledge, histomorphological studies of tissues from the surrounding of highly cross – linked polyethylene components have not been reported yet. The aim of this study was to examine such tissues for particles, released from highly cross – linked polyethylene cups and to compare the findings with those of conventional polyethylene. Material and methods: So far, periprosthetic tissues retrieved at revisions of 11 total hip endoprostheses with highly cross – linked polyethylene cups could be analysed. The revisions became necessary 3 to 50 months after implantation because of cup loosening (4), stem loosening (1), infection (3), periprosthetic fracture of the femur (1), multiple dislocations (1) and periarticular ossification (1). The findings were compared with those of 5 artificial joints (2 ABG, 2 Müller Cup older design, 1 Metalback pressfit) with conventional polyethylene cups and 54 to 231 months of function. 5 μm sections were made from the tissues and conventionally stained with HE and van Gieson. Morphometric measurements were done using objectives 10 and 40 of an Olympus microscope and the ‘Analysis’ program of Soft Ware Imaging GmbH. In the Durasul TM – cases, the total amount and the total area of particles were ascertained while in the cases used for comparison only random CX 40 samples could be measured because of the much higher content of particles. Results: The DurasulTM cases showed in contrast to the cases with conventional polyethylene cups, no distinct
Introduction: It is well known that the fate of biomaterials is determined by the distribution of proteins attached to the surface from the initial contact with blood or serum. This profile determines wether a material is inert, creates a foreign body response or is bioactive. Bioinert materials, such as polyethylene completely denature surface proteins, whilst materials inducing inflammatory responses are predisposed to complement protein attachment. Bioactive materials such autologous tissue grafts adsorb, but do not denature serum proteins such as fibronectin and Von Willebrand’s factor. This does not interfere with the healing cascade. This aim of this study is to prepare a synthetic bone graft substitute that activates the body’s autologous healing cascade by activating platelets, without activating a complement response through the controlled adsorption of serum proteins. Methods: Polymers composed of varied concentration of acrylic acid (AA) and comonomers (methyl, ethyl and butyl methacrylates (MMA, EMA, BMA)) were prepared in glass vials by free radical polymerisation. Fresh blood was collected from a healthy donor and pipetted immediately into each chamber. Glass was used as a control. The chambers were incubated at 37o C for 2 hours. The surface morphology was examined using Scanning Electron Microscopy (SEM). Concentration of complement protein C5a and prothrombin fragments 1 and 2 were determined using commercial ELISA kits.
Ceramic-on-ceramic bearing is an attractive alternative to metal-on-polyethylene bearing due to the unique tri-bological advantages of alumina. However, despite the long-term satisfactory results obtained so far in the vast majority of patients, failure may occur in a few cases. Clinical, radiographic, laboratory and microbiological data of 30 consecutive subjects with failed alumina-on-alumina total hip arthroplasties (THA) were analyzed to define if
The retear of the rotator cuff (RC) repair is a significant problem. Usually it is the effect of poor quality of the tendon. The aim was to evaluate histologically two types of RC reconstruction with scaffold. We have chosen commercially available scaffold polycaprolactone based poly(urethane urea). Rat model of supraspinatus tendon injury was chosen. There were four study groups: RC tear (no repair) (n=10), RC repair (n=10), RC repair augmented with scaffold (n=10) and RC reconstruction with scaffold interposition between tendon and bone (n=10). The repairs were investigated histologically at 6 and 16 weeks. The results in two groups in which scaffold was used had significantly better scores at 6 weeks comparing to non-scaffold groups (16,4±3, 17,3± 2,8 vs. 12,5±4,4, 13,8±1,4 respectively) and 16 weeks (23±1,9, 22,8±1,6 vs. 13,8±3,3, 14,9± 3,8 respectively). Results in two scaffold groups improved between 6 and 16 weeks. Signs of
Tissue engineering is a promising approach to regenerate damaged skeletal tissues. In particular, the use of injectable hydrogels alleviates common issues of poor cell viability and engraftment. However, uncontrolled cell fate, resulting from unphysiological environments and degradation rates, still remain a hurdle and impedes tissue healing. We thus aim at developing a new platform of injectable hyaluronic acid (HA) hydrogels with a large panel of properties (stiffness, degradation…) matching those of skeletal tissues. Hence, HA with different molecular weights were functionalized with silylated moieties. Upon injection, these hydrogels formed through a sol-gel chemistry within 5 to 20 minutes in physiological conditions, as demonstrated by rheological characterization. By varying the crosslinking density and concentration, we obtained hydrogels spanning a large range of elastic moduli (E = 0.1–20 kPa), similar to those of native ECMs, with tunable biodegradation rates (from 24 hours to > 50 days) and swelling ratios (500 to 5000% (w/w)). Cell viability was confirmed by Live/Dead assays and will be completed by in vivo subcutaneous implantations in mice to study the
Recent studies about hip stability after total hip arthroplasties (THA) concerned differences regarding bearings: ceramic on ceramic (CoC) presenting less dislocations on the long term compared to metal or ceramic on polyethylene. The hypothesis is a difference in the healing process of periarticular tissues, with a stronger fibrous tissue for the first one, and more
Adverse reaction to metal debris (ARMD) is well recognised as a complication of large head metal on metal total hip replacement (THR) leading to pain, bone and tissue loss and the need for revision surgery. An emerging problem of trunnionosis in metal on polyethylene total hip replacements leading to ARMD has been reported in a few cases. Increased metal ion levels have been reported in THR's with a titanium stem and a cobalt chrome head such as the Accolade-Trident THR (Stryker). We present 3 cases of ARMD with Accloade-Trident THR's with 36mm cobalt chrome head and a polyethylene liner. Metal ion levels were elevated in all three patients (cobalt 10.3 – 161nmol/l). Intraoperative tissue samples were negative for infection and inflammatory markers were normal. Abnormal fluid collections were seen in all three cases and bone loss was severe in one patient leading to a proximal femoral replacement. Histology demonstrated either a non-specific inflammatory reaction in a case which presented early or a granulomatous reaction in a more advanced case suggesting a local
Total joint arthroplasty is the most significant advance in the treatment of end-stage arthritic disease of major joints. Despite the clinical success of this surgical procedure, however, some total joint prostheses fail, and although a failed prosthesis can be replaced, the results of revision arthroplasty are not as good as the first time. Studying the failed prosthesis and the associated bone and soft tissues provides insight into the causes of failure. Most prosthetic failures are the result of structural limitations of the implant components. Although material failure may be sudden, a much more common cause is gradual aseptic loosening of the prostheses. Aseptic loosening is caused by both mechanical (gradual loss of material by wear) and biological (osteoclastic resorption of adjacent bone) factors. Wear particles induce a
Background. Aseptic loosening of cemented femoral stems results from migration of wear particles along the bone-cement interface, producing a
Innominate Osteotomy first described by Salter is one of the commonest procedures performed for treatment of Developmental Dysplasia of the Hip (DDH) in children. We recently described a less invasive technique for Innominate Osteotomy, which significantly reduces the operation time without compromising outcome (J Pediatr Orthop B. 2010 Jul;19(4):318–22). As part of the evolution of this procedure we now routinely use bioabsorbable pins (INION OTPS PIN, made from co-polymers of L-lactic acid, D-lactic acid and trimethylene carbonate) instead of K-wires to secure the graft. We prospectively followed-up 120 consecutive cases done using bioabsorbale pins over a 2 year period. The surgical technique was as described in our less invasive innominate osteotomy paper. Average age at surgery was 24 months (18–52) with mean follow-up period of 15 months (6–24 months). The mean preoperative acetabular index was 36.2. o. Our results show a mean acetabular index of 18.7. o. (P< 0.0001) at latest follow-up with no loss of correction. We recorded three superficial wound infections (one MRSA), all resolved uneventfully. There was no
The pathologies of the hip (epiphisiolysis, Perthes, congenital dysplasia) cause invalidating outcomes in young patients. In the years many authors searched for the golden standard if total hip arthroplasty is necessary. From Smith-Petersen to McKee, to Amstutz the saving of the femoral neck has been the main objective, with the longevity of the system. Therefore the combination metal-metal has been used for articular components, because the friction of metallic components creates sub-micron metallic particles causing only minimal
We reviewed the results of 545 consecutive total hip replacements using a cementless non-coated high-density polyethylene acetabular component combined with a cemented Muller stem at five to 10 years. In all, 421 patients (445 hips) were available for review, 118 by questionnaire and 303 by examination and radiography. Of these, 86% had a good or excellent result. We found a high rate of radiological loosening of the cup after the sixth year, and a high rate of clinical loosening after the eighth year. Loosening was commoner in women, in younger patients and where a smaller size of acetabulum had been used. Calcar resorption was significantly related to loosening of the acetabulum. Loosening appeared to be mainly due to polyethylene debris produced by micro-movement of the acetabulum against the bone, which had resulted in a giant cell
Aims: Aware of good results recently obtained with synthetic biodegradable polymers, in order to avoid problems seen with the use of metal implants, we adopted an intramedullary absorbable poly-l-lactic acid pins þxation in displaced metatarsal fractures. This paper reports on the results we have obtained. Methods: Eleven patients underwent open reduction and internal þxation of the fracture fragments using biodegradable pins of the following sizes: diameter 3,2 millimetre x length 5.0–6.0–7.0 millimetre. Clinical examination and X-ray controls were done three, six, twelve weeks and one year after surgery. In addition all patients were followed up with magnetic resonance imaging (MRI). Results: All patients operated healed in about 2 months without cast immobilization or prolonged rest. Serial radiographs showed good alignment of the bone and solid union at the fracture site. No inßammatory
Objectives: A stable shoulder is essential for proper elbow and hand function after oncologic resection of the shoulder girdle. We describe a surgical technique for replacing the shoulder joint capsule using synthetic mesh after resections of the shoulder girdle that resulted in gross intraoperative instability of the shoulder joint. Methods: 68 patients who underwent shoulder girdle resection between 1989 and 2006 were identified in our prospective database. This report focuses on nine patients whose shoulder joint was reconstructed with synthetic mesh. All patients were followed on a 3 monthly basis. Shoulder joint instability was determined from clinical records, database and radiographs. Results: Nine patients underwent shoulder joint reconstruction with synthetic mesh. One patient underwent a shoulder disarticulation within 30 days of the index surgery and was excluded from this rapport. No dislocations were noted during follow-up (range 3–48 months). Radiographs revealed an average vertical displacement of the humeral head compared to its original position of 0.7 cm (range 0–1.7 cm). There were two surgical complications. In one patient the humeral prosthesis migrated proximally and eroded through the skin requiring additional surgery. In another case erosion of the distal clavicle was noted. This was biopsied and
Fusion remains the standard of care and is associated with a high satisfaction rate. But.… fusion generally requires 6 weeks of restricted weight bearing or immobilization. Potential problems include 1) nonunion, 2) malunion, 3) sesamoid pain (from DJD), 4) late onset IP1 DJD. Complete joint replacement has been performed with a number of different designs since the early 1970's. The metal and poly designed implants are associated with a high failure rate, presumably from high shear loads, eccentric axial loads, poor fixation and bone stock problems. Resurfacing of both sides of the joint with a one piece silicone based crosslinked rubber {“silastic”} in rheumatoid patients appears to function better with use of metal grommets to reduce generation of particle debris and
Introduction and Aims: Treatment of rotator cuff tendon tear presents a significant therapeutic challenge to surgeons. Porcine small intestinal submucosa (SIS) is a biomaterial approved by TGA and FDA for the repair of rotator cuff tendon tear. The aims of this study are to evaluate the safety and efficacy of SIS. Method: SIS purchased from DePuy Johnson &
Johnson was examined by histology and PCR technique. The material was also implanted into mice and rabbits for the evaluation of biological reaction and inflammatory response. Porcine immunoreceptor DAP12 gene was used to examine if the material contained porcine DNA. Results: Fresh SIS membrane before implantation contains multiple layers of spindle-shaped cells mixed with a small population of round-shaped cells. Chloro-acetate esterase staining showed that the round-shaped cells are positive, indicating that they are mast cells. The tissue architecture of SIS mimics to tendon structure as evidenced by H&
E staining. To further confirm if cells present in SIS material were porcine origin, nested PCR for the amplification of DAP12 gene was used. The result demonstrated that SIS membrane contain porcine DNA materials. Conclusion: SIS contains porcine cells and nuclei acid, which contradicts with current views that SIS is a cell-free biomaterial. Although no
1 . Implants of heterogenous cartilage are known to excite a
Although it is generally accepted that surgical treatment is the treatment of choice in chronic TA ruptures, therapeutic options are difficult. Traditional options include grafts (natural, allografts and synthetic grafts) and end to end repair. Natural grafts described include fascia lata and plantaris tendon. Synthetic materials such as Dacrongrafts, Marlex mesh and carbon fibers have been used. There are significant complications from graft and end to end repair. These include wound necrosis, delayed union, infection,
Aims: To investigate if coralline hydroxyapatite conduct bone formation in human spine. Methods: During revision surgery specimens were taken from the fusion mass from 13 patients, who received spinal instrumentation (Titanium alloy) and fusion with coralline hydroxyapatite. The age of patients at the time of revision surgery was 46±20 years. The time lapsed from the implantation of coralline hydroxyapatite (ProOsteon) was 11±11 months. The indication for revision was infection, pseudarthrosis, technical error, and pain related to hardware. The diagnosis for primary fusion was degenerative disease, spinal trauma and scoliosis. Coralline hydroxyapatite was applied on the posterior decorticated elements of the instrumented spine without any mixture with bone graft. Material from ten different places from the fusion mass was intraoperatively taken and the histological evaluation was made using the Hematoxylin-eosin histological stain. Results: There was a concentration of foreign-body like giant cells &
development inflammatory granulomatous tissue around hydroxyapatite granules, which was gradually replaced by dense connective collagen tissue. Both inflammatory granulomatous and collagen tissue showed areas with
On hundred and ninety unselected patients, mean age 62(SD12.8) were operated upon by one surgeon, using same approach. HSS improved from 33 to 75 post-operatively, the low figures reflecting a high percentage of Charnley C patients (71%). There was a 5% mortality rate from unrelated causes. Early complications included a 2.97% femoral fracture rate within 4–8 weeks of surgery (analysis showed no relation between implant position, BMI, age or Charnley classification, but there was correlation between high level of satisfaction and early weight bearing). There was one infection and one dislocation. Late complications included 3 periprosthetic fractures, 3 dislocations and 2 aseptic cup failures. However, 30% of patients developed groin pain, increasing stiffness and clunking at 1–2 years following surgery. These patients were investigated with an ultrasound scan. 28 patients (14%) had an effusion and were aspirated. Chrome and cobalt levels in synovial fluid, blood and urine were very high. 13 patients have been revised. 1 showed infection, 10 showed metal allergy and 2 a mixed picture of allergy and
Introduction: Non union of the humerus in the ostoeportic bone is a great challenge for the orthopedic surgeon. The non weight bearing nature of this bone together with extreme osteoporosis seen in the elderly had rendered a high degree of failure in different modes of internal fixation of established humeral non union. Tantalum is a trabecullar metal with biomechanical properties similar to bone with a high modulus of elasticity and low rigidity. It is proved both in vitro and in vivo to induce excellent bone and vascular in growth and have been used successfully treating other application in orthopedics. We have introduced the tantalum rod for the treatment of humeral non union in the elderly. Patients and Methods: Six patients with humeral non-union were selected for tantalum rod implantations. All were above 60 years old. All patients had established non and 4 had failures after previous osteosynthesis. The surgical technique was exploration of the fracture site via a posterior or an anterolateral approach, debridement of the fracture site and intramedullary insertion of a 100 mm x 10 mm tantalum rod. No bone grafting was used. Ancillary fixation included a 4.5 broad DCP plate with screws drilled into both bone and rod or screws alone drilled into the bone and tantalum construct. Follow up period was up to one year. Results: All fractures united clinically and radiographicaly up to 3 months. All patients achieved satisfactory shoulder and elbow range of motion and regained functional activity. No infection or
Surgibone (Unilab R) is a dry bone graft substitute prepared from Canadian bovine bone. It contains hydroxyapatite and 20–29% protein. The manufacturer claims that it is biocompatible; does not lead to
Methods: Sixty pseudo-capsular tissues from loose shoulder, hip and knee (20 each) arthroplasties and 30 capsular tissues from primary total joint arthroplasty (TJA) patients (10 each; 12 rheumatoid arthritis [RA], 18 osteo-arthrosis [OA]) were investigated for mRNA and protein expressions of IL-1ß (interleukin-1 b, IL-1Ra (interleukin-1 receptor antagonist), MMP 1 (matrix matalloproteinase-1)-, TIMP 2 (tissue inhibitor of MMPs-2) using in situ hybridisation and immunohistochemistry. Polyethylene and metal debris in the same sections were semi-quantified simultaneously. Results: IL-1ß mRNA and proteins were expressed in most RA primary and revision tissues and were less expressed in OA primary tissues. In contrast, IL-1Ra mRNA was found in most primary OA tissues and less in RA primary and the revision tissues. The ratio of staining intensities of IL-1ß/IL-1Ra mRNA was higher in revision and primary RA tissues compared with the primary OA tissues. MMP-1 protein expression was correlated with the IL-1ß/IL-1Ra ratio. Polyethylene (PE) debris was found in 56 out of 60 of the revision tissues. Their sizes were different in the hip (mainly small, <
30 mm in diameter), the knee (mainly large, >
300 mm) and the shoulder (all sizes). The expressions of the detected factors were highly correlated with the concentration of the PE debris but with not their sizes. Conclusions: The high ratio of IL-1ß/IL-1Ra in primary RA and revision tissues and its correlation with MMP-1 expression and PE debris concentration indicated that an over-expression of IL-1ß and/or regulation downwards of IL-1Ra is an important event in inflammatory disorders and the
Among the wide variety of bone substitutes presently available, pure β-tricalcium phosphate ceramics have become available (Biosorb®; Aesculap, Tuttlingen). During the first 12 months of a prospective clinical trial, Biosorb® products were implanted in 21 patients. The ceramics were used in a variety of clinical settings, ranging from pelvic osteotomies in children (n=9), to filling of bone cysts or osseous defects (n=4), to dorsal spondylodesis (n=6), as well as for the grafting of pseudarthroses (n=2). Average follow-up period was 13 (6–18) months. The β-TCP granules, when used as part of a composite graft in combination with autologous bone, were completely resorbed after an average period of 14 weeks, while the cubes required 12 to 15 months. The more massive wedges have shown only a decrease in size and radio density. Due to the ability of the cubes and wedges to bear loads of up to 30 MPa, they were successfully implanted during pelvic osteotomies to augment or completely replace the bicortical grafts. Complications or
Summary Statement. To evaluate carbon-fiber-reinforced PEEK as alternative biomaterial for total disc arthroplasty a closed loop between biotribology (in vitro), application of sterile particle suspensions in the epidural space of rabbits and biological response in vivo was established. Introduction. To prevent adjacent level degeneration in the cervical spine, total disc arthroplasty (TDA-C) remains an interesting surgical procedure for degenerative disc disease. Short- or midterm complications are migration, impaired post-operative neurological assessment due to artefacts in x-ray and MRI diagnosis and substantial rates of heterotopic ossification. The idea was to create a TDA-C design based on a polymer-on-polymer articulation to overcome these limitations of the clinically established metal-on-polyethylene designs. The objective of our study was to characterise the biotribological behaviour of an experimental cervical disc replacement made out of carbon-fiber-reinforced (CFR) PEEK and evaluate the biological response of particulate wear debris in the epidural space in vivo. Materials & Methods. In vitro wear simulation acc. to ISO 18192-1 was performed for 10 million cycles on a clinically established TDA-C device (Aesculap, Tuttlingen) made of cobalt-chromium-on-polyethylene in a direct comparison to an experimental disc prototype made of CFR-PEEK. An estimation of particle size and morphology was done acc. to Affatato et al. [5] and sterile suspensions of comparable particles (size 90% < 1 µm) in phospate buffered saline (PBS) were produced [6] for the application in the epidural space of 36 white new zealand rabbits. The particle concentration was 1 mg/ml with a volume of 0.2 ml injected percutaneously using fluoroscopic guidance and the inflammatory response was assessed 3 and 6 months post-operatively in a direct comparison between the groups PBS (control), UHMWPE and CFR-PEEK. Results. The gravimetric wear rate was for the cobalt-chromium-on-polyethylene TDA-C device as a clinical reference 1.0 ± 0.1 mg/ million cycles, compared to 0.02 ± 0.02 mg/ million cycles for the experimental CFR-PEEK articulation (p < 0.001), whereas the cumulative amount of wear of the CFR-PEEK TDA-C prototypes (0.5 ± 0.23 mg/ million cycles) was decreased by an order of a magnitude compared to cobalt-chromium-on-polyethylene (12.1 ± 1.46 mg/ million cycles) (p < 0.001). For CFR-PEEK and UHMWPE most of the particles were observed in a submicron size range and the morphology was comparable. Histopathological examination demonstrated wear debris in the vertebral canal of injection sites surrounded by inflammatory cells. The inflammation was limited to the epidural space around the particles and polymer particles were associated by a low grade
Introduction and Objectives: The coating of implants with biomaterials seems to be a step further toward the ideal biological integration of an inert implant in live recipient bone where it will be subjected to load and movement. The goal of this study is to present results from 70 hip prostheses with implantation of a bioglass-coated stem. Materials and Methods: The “Grupo para el Estudio del Biovidrio” [Group for the Study of Bioglass] and the Stazione del Vetro de Murano experimented with a biocompatible, osteoconductive bioglass in 1992, creating the Biovetro patent as the first bioglass used for the coating of the CRM total hip prosthesis (Seipi-Bio-implant). In 1992, implantation of this prosthesis was begun in Italy and Spain. In 1994 and 1995, we implanted 70 TiAlva CRM stem total hip prostheses with the proximal two-thirds coated with an 80-micron thick layer of Biovetro. A Ceraver-Osteal impacted cup covered with a titanium mesh was used in all cases. Results: Of the 70 CRM prostheses implanted, adequate clinical and radiographic examination was possible in 62 cases, with an 8-year follow-up time. Clinical evaluation was done using the Merle D’Aubigne Postel criteria: pain, mobility, and gait. In 77% of patients, results were excellent or good, while 23% had fair or poor results. Radiographic evaluation according to Engh’s criteria for cementless stems showed 56 (90%) stable stems, 1 (1.6%) unstable stem, and 5 (8%) stem revisions, in one case due to infection. Survival rate for this stem at 8 years was 91.4%. Discussion and Conclusions: Based on these results, we believe Biovetro coating produces worse osteointegration than HA due to: 1) Appearance of a fibrous interface with a macrophage
INTRODUCTION. The advantages of large diameter metal on metal total hip arthroplasty (MoM THA) and hip resurfacing arthroplasty are decreased wear rate, preservation of bone stock, anatomical restoration and enhanced stability. Large amounts of metal wear particles and metal ions are released which may induce adverse reactions including local soft tissue toxicity, hypersensitivity reactions, bone loss and risk of carcinogenesis. Aseptic loosening can be the result of a peri-prosthetic osteolysis generated as a result of a biological response to particulate wear debris. No reports in the literature exist as to whether circulating levels of Chromium (Cr) and Cobalt (Co) decrease upon removal of a symptomatic large diameter MoM implant or whether levels remain high due to the effect of metal ions debris left behind in the soft tissues after revision surgery. PATIENTS AND METHODS. Between June 2006 and June 2009 we undertook 44 revision surgeries of both large head MoM THAs (femoral head diameter 38mm) and metal-on-metal hip resurfacings for suspected metallosis. Mean time from original implant to revision was 4 years, 8 months (1yr 4mo–7yr 9mo). The mean follow up evaluation was 2 years and 2 months (1yr 2mo–4 years). Blood samples were taken for whole blood Cr and serum Co according to a recognised protocol and compared with reference levels indicated by the Medicines and Healthcare Regulatory Agency recommendation of less than 7ppb for Cr (130nM/L) and Co (119nM/L). RESULTS. 42 patients were found to have histological evidence of either metal allergy, metal toxicity or
Trabecular materials show great promise for soft-tissue attachment to prosthetic implants. Results with Tantalum have been very encouraging, however, it remains unclear if this in-growth is secondary to the specific metal or its generic structure,. If structure, is there a specific tolerance with respect to porosity and pore size? In a canine model, bulk blocks of porous alumina ceramic were shown to be completely ingrown by four weeks. The type material was not a factor, and effect of pore size revealed that there is a wide tolerance in facilitating in-growth with the larger pores having the greatest attachment strength (p=0.004). This study examines the in-vivo soft tissue in-growth potential of porous alumina ceramic and the effect of three distinct pore size ranges on this process. Alumina ceramic implants of fixed porosity (~ 85%) were designed in three pore size ranges (100–200, 250–400 and 600–800 μM). Using an established canine model, six implants (two of each type) were implanted in the dorsal subcutaneous tissues of tweleve mature canines and examined histologically and mechanically at four, eight and sixteen weeks with respect to type, amount and strength of soft tissue in-growth. Soft tissue in-growth was grossly evident in all implants at each time interval, and in each pore size. Microscopic examination revealed neo-vascularized in-growth throughout the implant, without evidence of inflammation or
Aim: The purpose of this paper was to describe the biological reaction imposed by a prosthetic ligament. Materials-Methods: Polyester-carbon synthetic matrices were implanted into 29 rabbits. The implants were transected centrally and reconstructed with resorbable suture material. At regular intervals from 4th day to 29 weeks, tissue samples from the ingrown implants were obtained for histology and mechanical testing. Light microscopy, DNA cytometry, immunohistochemical analysis of the collagen types, transmission and scanning electron microscopy were carried out. Ultimate tensile strength (UTL), elongation to failure (EF) and structural stiffness (SS) were determined at intervals of 8, 16 and 29 weeks. Results: The ingrowth of tissue into the scaffold provided a significant increase in tensile strength, which improved with time. The UTL significantly increased from 18.86 N ±14.69 at 8 weeks to 51.4 N ±14.64 at 29 weeks. Light microscopy showed no infl ammation or
PURPOSE: Trapezial excision with ligament reconstruction combined with tendon interposition has proven to be a highly effective technique for the treatment of OA of the CMC joint. We believe the same procedure is possible with use of modern orthobiologics. Methods: 35 patients underwent surgical treatment for CMC arthritis with a new technique using Graft Jacket (Wright Med.) instead of FCR. Graft Jacket is an acellular human collagen (dermis) allograft. It is rapidly revascularized, repopulated with host cells and has high tensile strength. Technique: The Graft Jacket was rehydrated and cut to create a 15cm strip. It was then placed around or sutured to the FCR (the anchor) and passed into the intramedullary cavity of the metacarpal as in the standard LRTI procedure. The remaining Graft Jacket is sutured together as an anchovy to fill the former trapezium gap, so that both suspension and interposition occurred. The mean age of the patients was 56 years and the median follow-up period was 1 year. All patients had marked pain and radiographic evidence of severe arthritis before surgery. Pain, grip and pinch (tip and key) strength, stability and range of motion were measured pre- and post-operatively. Pain was assessed on a VAS (Visual Analog Scale). The ability to perform ADLs (Activities of Daily Living) requiring use of the thumb and to return to work were analyzed as well. Following surgery all thumbs were immobilized in a static splint for 10 days and then were placed into a removable orthoplast splint for 4–6 weeks. Radiographic examination was performed in all patients at the 10th post-op day, and also at 2 and 6 months after surgery. Results: Significants improvements were seen with grip strength (average 25lb) and tip (average 3.5lb) and key (average 4.5lb) pinch strength as well as palmar and radial abduction (average 25o). Pain was significantly reduced with an average of 6.0 on the VAS. There were no
In the Bunge repair strategy, a tube containing a Schwann cell cable bridges the cord lesion. Regenerating axons penetrate the proximal cord-graft interface and grow through the Schwann cell cable but the axons do not grow across distal cord-graft interface and into distal cord stump. Regeneration of axons can be promoted by applying neurotrophic factors in graft. Adding a matrix containing genes encoding for neurotrophic factors in the SC bridge between the proximal and distal cord-graft interfaces may promote axonal regeneration into the graft and the distal cord stump. Methods: There were 22 female fisher rats. One segment of 5-mm spinal cord was removed at T9 level. 6 of them (group1) received Schwann cell grafts positioned between transected stumps to test their efficacy to serve as bridges for axonal regeneration. 16 of them (group 2) received gene-treated Schwann cell grafts. All animals survived 4 weeks. Functional result was assessed by BBB behavior test everyweek after surgery. Fast-Blue injection into SC cable one week before perfusion. Immunocytochemistry to detect labeled neurons in cord, brain stem, and cortex. Toluidine blue stain for myelinated axons. Results: A bridge between the severed stumps had been formed in all animals, as determined by the gross and histological appearance and the ingrowth of propriospinal axons from both stumps. In group 1, near the bridge midpoint there was a mean of 1800 myelinated axons and eight times as many nonmyelinated, ensheathed axons. In group 2, more fibrous tissue surrounding grafted cords were noted. Myelinated axons can hardly find in group 2 animals excepted some unmyelinated axons. Histological examination shows vigorous inflammatory reaction with Macrophage dominant in the bridges. Conclusions: This study demonstrates that Schwann cell grafts serve as bridges that support regrowth of both ascending and descending axons across a gap in the adult rat spinal cord. The ground substance of gene-treated graft induced
Introduction Reported clinical results suggest that vertebroplasty is a safe and effective technique for providing pain relief. However, information about the long-term effect of PMMA on the adjacent intervertebral discs and the augmented bone is lacking. Adjacent intervertebral discs may be at higher risk of degeneration due to nutritional constraints. Bone loss in augmented vertebrae may occur due to mechanical stress-shielding or toxicological effects. The aim of the present study was therefore to investigate the effect of PMMA augmentation on intervertebral disc and bone tissue after 6 and 12 months, using an animal model. Methods In 12 skeletally mature sheep, 2.0ml PMMA (Simplex P) was injected into three lumbar vertebrae (approved by Animal Ethics Committee). Two injection holes were drilled into the middle of three vertebrae at a distance of 5.0mm from the cranial and caudal endplate and 1.0ml PMMA was injected into each hole. Four weeks before euthanasia, animals received an injection of tetracycline for bone labeling. Postmortem, T1- and T2-weighted sagittal and axial MR images were taken prior to fixation in 80% ethanol. Spines were cut into specimens containing one intervertebral disc and half of the two adjacent vertebrae. The discs which were two levels above the first augmented vertebra served as controls. Microsections were stained with H&
E, Goldner, Alcian blue-PAS and Safranin O. MRI signal intensity and morphology of discs were evaluated qualitatively. Histomorphological analysis of discs and endplates was conducted using published criteria [. 1. ]. Presence of bone remodeling, fibrous tissue and