Biomechanical and histological evaluation of hydrogel implants in articular cartilage

We evaluated the mechanical behavior of the repaired surfaces of defective articular cartilage in the intercondylar region of the rat femur after a hydrogel graft implant. The results were compared to those for the adjacent normal articular cartilage and for control surfaces where the defects remained empty. Hydrogel synthesized by blending poly(2-hydroxyethyl methacrylate) and poly(methyl methacrylate-co-acrylic acid) was implanted in male Wistar rats. The animals were divided into five groups with postoperative follow-up periods of 3, 5, 8, 12 and 16 weeks. Indentation tests were performed on the neoformed surfaces in the knee joint (with or without a hydrogel implant) and on adjacent articular cartilage in order to assess the mechanical properties of the newly formed surface. Kruskal-Wallis analysis indicated that the mechanical behavior of the neoformed surfaces was significantly different from that of normal cartilage. Histological analysis of the repaired defects showed that the hydrogel implant filled the defect with no signs of inflammation as it was well anchored to the surrounding tissues, resulting in a newly formed articular surface. In the case of empty control defects, osseous tissue grew inside the defects and fibrous tissue formed on the articular surface of the defects. The repaired surface of the hydrogel implant was more compliant than normal articular cartilage throughout the 16 weeks following the operation, whereas the fibrous tissue that formed postoperatively over the empty defect was stiffer than normal articular cartilage after 5 weeks. This stiffness started to decrease 16 weeks after the operation, probably due to tissue degeneration. Thus, from the biomechanical and histological point of view, the hydrogel implant improved the articular surface repair.30731

Survival Rates Of The Himex Extensible Nail In The Treatment Of Children With Osteogenesis Imperfecta

Objective: To evaluate the performance of an extensible nail with hooks, named HIMEX, in osteogenesis imperfecta (OI) deformities. Methods: All child patients were operated on with HIMEX from 1990 to 2004. The number of fractures, reappearance of deformities, improvement of motor development before and after the use of HIMEX, and the incidence of the migration and nail survival were compared. Results: Fourteen patients, with ages from 2 to 18 years, including 8 females, underwent 46 procedures, 39 primary and 7 re-operations. The average age at the first fracture was 148.21 days, and there was an average of 42.6 fractures per patient prior to HIMEX placement. Of the forty-six bones affected, 28 were femurs and 18 were tibias. Average follow-up care lasted 80.21±36.71 months. There was a statistically significant decrease (0.78) in the number of fractures per patient and an improvement in walking in seven of the fourteen patients. Revision occurred in 18% of patients and migration of the nail occurred in 12% (5/39). Eighty percent of the nails remained in situ until 108 months, with femoral procedures lasting significantly longer than tibial procedures. The type of OI and the age at the procedure did not significantly affect the incidence of revision. Conclusion: HIMEX significantly reduced the number of fractures, presenting lower incidence of migration and higher survival rates than those described in literature.186343348Sofield, H.A., Millar, E.A., Fragmentation, realignment, and intramedullary rod fixation of deformities of the long bones in children. A ten-year appraisal (1959) J Bone Joint Surg Am, 41, pp. 1371-1391Williams, P.F., Fragmentation and rodding in osteogenesis imperfecta (1965) J Bone Joint Surg Br, 47, pp. 23-31King, J.D., Bobechko, W.P., Osteogenesis imperfecta. An orthopaedic description and surgical review (1971) J Bone Joint Surg Br, 53, pp. 72-89Williams, P.F., Cole, W.H., Bailey, R.W., Dubow, H.I., Solomons, C.C., Millar, E.A., Current aspects of the surgical treatment of osteogenesis imperfecta (1973) Clin Orthop Relat Res, 0 (96), pp. 288-298Tiley, F., Albright, J.A., Osteogenesis imperfecta: treatment by multiple osteotomy and intramedullary rod insertion. Report on thirteen patients (1973) J Bone Joint Surg Am, 55, pp. 701-713Li, Y.H., Chow, W., Leong, J.C., The Sofield-Millar operation in osteogenesis imperfecta. A modified technique (2000) J Bone Joint Surg Br, 82, pp. 11-16Santilli, C., Akkari, M., Waisberg, G., Andrade, A.L.L., Costa, U., Silva, A.L.M., A operação de Sofield e Millar no tratamento da osteogênese imperfeita (2004) Acta Ortop Bras, 12, pp. 226-232Bailey, R.W., Dubow, H.I., Evolution of the concept of an extensible nail accom- modating to normal longitudinal bone growth: clinical considerations and im- plications (1981) Clin Orthop Relat Res, 0 (159), pp. 157-170Rodriguez Jr., R.P., Wickstrom, J., Osteogenesis imperfecta: a preliminary report on resurfacing of long bones with intramedullary fixation by an extensible intramedullary device (1971) South Med J, 64, pp. 169-176Rodriguez, R.P., Report of multiple osteotomies and intramedullary fixation by an extensible intramedullary device in children with osteogenesis imperfecta (1976) Clin Orthop Relat Res, 0 (116), p. 261Marafioti, R.L., Westin, G.W., Elongating intramedullary rods in the treatment of osteogenesis imperfecta (1977) J Bone Joint Surg Am, 59, pp. 467-472Rodriguez, R.P., Bailey, R.W., Internal fixation of the femur in patients with osteo- genesis imperfecta (1981) Clin Orthop Relat Res, 0 (159), pp. 126-133Lang-Stevenson, A.I., Sharrard, W.J., Intramedullary rodding with Bailey-Dubow extensible rods in osteogenesis imperfecta. An interim report of results and complications (1984) J Bone Joint Surg Br, 66, pp. 227-232Gamble, J.G., Strudwick, W.J., Rinsky, L.A., Bleck, E.E., Complications of intramedulla- ry rods in osteogenesis imperfecta: Bailey-Dubow rods versus nonelongating rods (1988) J Pediatr Orthop, 8, pp. 645-649Ryöppy, S., Alberty, A., Kaitila, I., Early semiclosed intramedullary stabilization in osteogenesis imperfecta (1987) J Pediatr Orthop, 7, pp. 139-144Stockley, I., Bell, M.J., Sharrard, W.J., The role of expanding intramedullary rods in osteogenesis imperfecta (1989) J Bone Joint Surg Br, 71, pp. 422-427Nicholas, R.W., James, P., Telescoping intramedullary stabilization of the lower extremities for severe osteogenesis imperfecta (1990) J Pediatr Orthop, 10, pp. 219-223Porat, S., Heller, E., Seidman, D.S., Meyer, S., Functional results of operation in os- teogenesis imperfecta: elongating and nonelongating rods (1991) J Pediatr Orthop, 11, pp. 200-203Jerosch, J., Mazzotti, I., Tomasevic, M., Complications after treatment of patients with osteogenesis imperfecta with a Bailey-Dubow rod (1998) Arch Orthop Trauma Surg, 117, pp. 240-245Luhmann, S.J., Sheridan, J.J., Capelli, A.M., Schoenecker, P.L., Management of lower- extremity deformities in osteogenesis imperfecta with extensible intramedullary rod technique: a 20-year experience (1998) J Pediatr Orthop, 18, pp. 88-94Wilkinson, J.M., Scott, B.W., Clarke, A.M., Bell, M.J., Surgical stabilisation of the lower limb in osteogenesis imperfecta using the Sheffield Telescopic Intramedullary Rod System (1998) J Bone Joint Surg Br, 80, pp. 999-1004Zionts, L.E., Ebramzadeh, E., Stott, N.S., Complications in the use of the ailey-Dubow extensible nail (1998) Clin Orthop Relat Res, 0 (348), pp. 186-195Janus, G.J., Vanpaemel, L.A., Engelbert, R.H., Pruijs, H.E., Complications of the Bailey- Dubow elongating nail in osteogenesis imperfecta: 34 children with 110 nails (1999) J Pediatr Orthop B, 8, pp. 203-207Karbowski, A., Schwitalle, M., Brenner, R., Lehmann, H., Pontz, B., Wörsdörfer, O., Experience with Bailey-Dubow rodding in children with osteogenesis imper- fecta (2000) Eur J Pediatr Surg, 10, pp. 119-124Mulpuri, K., Joseph, B., Intramedullary rodding in osteogenesis imperfecta (2000) J Pediatr Orthop, 20, pp. 267-273Sillence, D., Osteogenesis imperfecta: an expanding panorama of variants (1981) Clin Orthop Relat Res, 0 (159), pp. 11-25Shapiro, F., Consequences of an osteogenesis imperfecta diagnosis for survival and ambulation (1985) J Pediatr Orthop, 5, pp. 456-462Hoffer, M.M., Bullock, M., The functional and social significance of orthopedic rehabilitation of mentally retarded patients with cerebral palsy (1981) Orthop Clin North Am, 12, pp. 185-191Root, L., The treatment of osteogenesis imperfecta (1984) Orthop Clin North Am, 15, pp. 775-790Gerber, L.H., Binder, H., Weintrob, J., Grange, D.K., Shapiro, J., Fromherz, W., Rehabilitation of children and infants with osteogenesis imperfecta (1990) A program for ambulation. Clin Orthop Relat Res., 0 (251), pp. 254-26

Minimal Invasive Ostheosintesis For Treatment Of Diaphiseal Transverse Humeral Shaft Fractures

Objective: To evaluate patients with transverse fractures of the shaft of the humerus treated with indirect reduction and internal fixation with plate and screws through minimally invasive technique. Methods: Inclusion criteria were adult patients with transverse diaphyseal fractures of the humerus closed, isolated or not occurring within 15 days of the initial trauma. Exclusion criteria were patients with compound fractures. Results: In two patients, proximal screw loosening occurred, however, the fractures consolidated in the same mean time as the rest of the series. Consolidation with up to 5 degrees of varus occurred in five cases and extension deficit was observed in the patient with olecranon fracture treated with tension band, which was not considered as a complication. There was no recurrence of infection or iatrogenic radial nerve injury. Conclusion: It can be concluded that minimally invasive osteosynthesis with bridge plate can be considered a safe and effective option for the treatment of transverse fractures of the humeral shaft. Level of Evidence III, Therapeutic Study.2229498Angelini, A.J., Livani, B., Flierl, M.A., Morgan, S.J., Belangero, W.D., Less invasive percutaneous wave plating of simple femur shaft fractures. A prospective series (2010) Int Orthop., 41 (6), pp. 624-628Heitemeyer, U., Claes, L., Hierholzer, G., Körber, M., Significance of postoperativestability for bony reparation of comminuted fractures. An experimental study Arch Orthop Trauma Surg., 1990 (3), pp. 144-149Gerber, C., Mast, J.W., Ganz, R., Biological internal fixation of fractures (1990) Arch Orthop Trauma Surg., 109 (6), pp. 295-303Miclau, T., Martin, R.E., The evolution of modern plate osteosynthesis (1997) Injury., 28 (SUPPL. 1), pp. A3-6Farouk, O., Krettek, C., Miclau, T., Schandelmaier, P., Guy, P., Tscherne, H., Minimally invasive plate osteosynthesis and vascularity: preliminary results of a cadaver injection study (1997) Injury, 28 (SUPPL. 1), pp. A7-12Farouk, O., Krettek, C., Miclau, T., Schandelmaier, P., Guy, P., Tscherne, H., Minimally invasive plate osteosynthesis: does percutaneous plating disrupt femoral blood supply less than the traditional technique? (1999) J Orthop Trauma., 13 (6), pp. 401-406Perren, S.M., Evolution of the internal fixation of long bone fractures. The scientific basis of biological internal fixation: choosing a new balance between stability and biology (2002) J Bone Joint Surg Br., 84 (8), pp. 1093-1110Livani, B., Belangero, W.D., Bridging plate osteosynthesis of humeral shaft fractures (2004) Injury., 35 (6), pp. 587-595Apivatthakakul, T., Arpornchayanon, O., Bavornratanavech, S., Minimally invasive plate osteosynthesis (MIPO) of the humeral shaft fracture. Is it possible? A cadaveric study and preliminary report (2005) Injury., 36 (4), pp. 530-538Apivatthakakul, T., Patiyasikan, S., Luevitoonvechkit, S., Danger zone for locking screw placement in minimally invasive plate osteosynthesis (MIPO) of humeral shaft fractures: a cadaveric study (2010) Injury., 41 (2), pp. 169-172Livani, B., Belangero, W.D., Castro de Medeiros, R., Fractures of the distal third of the humerus with palsy of the radial nerve: management usingn minimally- invasive percutaneous plate osteosynthesis (2006) J Bone Joint Surg Br., 88 (12), pp. 1625-1628Ziran, B.H., Belangero, W., Livani, B., Pesantez, R., Percutaneous plating of the humerus with locked plating: technique and case report (2007) J Trauma., 63 (1), pp. 205-210Schwarz, N., Windisch, M., Mayr, B., Minimally Invasive anterior plate osteosynthesis in humeral shaft fractures (2009) Eur J Trauma Emerg Surg., 35 (3), pp. 271-276Concha, J.M., Sandoval, A., Streubel, P.N., Minimally invasive plate osteosynthesis for humeral shaft fractures: are results reproducible? (2010) Int Orthop., 34 (8), pp. 1297-1305Hudak, P.L., Amadio, P.C., Bombardier, C., Development of an upper extremity outcome measure: the DASH (disabilities of the arm, shoulder and hand) [corrected]. The Upper Extremity Collaborative Group (UECG) (1996) Am J Ind Med., 29 (6), pp. 602-608Thompson (1918) e Henry (1924 e 1966) - The humerus (2003) Surgical Exposures in Orthopaedics, pp. 67-103. , in: Hoppenfeld S., De Boer P., The anatomic Approach 3rd Ed;Charpter 2Livani, B., Belangero, W.D., Osteossíntese de fratura diafisária do úmero com placa em ponte: apresentação e descrição da técnica (2004) Acta Ortop Bras., 12 (2), pp. 113-117Gustilo, R.B., Anderson, J.T., Prevention of infection in the treatment of one thousand and twenty-five open fractures of long bones: retrospective and prospective analyses (1976) J Bone Joint Surg Am., 58 (4), pp. 453-458Gustilo, R.B., Mendoza, R.M., Williams, D.N., Problems in the management of type III (severe) open fractures: a new classification of type III open fractures (1984) J Trauma., 24 (8), pp. 742-746Benegas, E., Amódio, D.T., Correia, L.F.M., Malavolta, E.A., Ramadan, L.B., Ferreira Neto, A.A., Estudo comparativo prospectivo e randomizado entre o tratamento cirúrgico das fraturas diafisárias do úmero com placa em ponte e haste intra medular bloqueada (analise preliminar) (2007) Acta Ortop Bras., 15 (2), pp. 87-92Kobayashi, M., Watanabe, Y., Matsushita, T., Early full range of shoulder and elbow motion is possible after minimally invasive plate osteosynthesis for humeral shaft fractures (2010) J Orthop Trauma., 24 (4), pp. 212-216Hunsaker, F.G., Cioffi, D.A., Amadio, P.C., Wright, J.G., Caughlin, B., The American academy of orthopaedic surgeons outcomes instruments: normative values from the general population (2002) J Bone Joint Surg Am., 84 (2), pp. 208-21

Mind The Gap Between The Fracture Line And The Length Of The Working Area: A Finite Element Analysis Using An Extramedullary Fixation Model

To determine the ideal working area for a simple transverse fracture line treated with a bridge plate. Methods: A 2-D finite element analysis of a hypothetical femur was performed for the quantitative evaluation of a large-fragment titanium alloy locking plate based on the principle of relative stability in a case of a simple transverse diaphyseal fracture. Two simulations (one case of strain and another case of stress distribution) were analyzed in three unique situations according to the von Mises stress theory. Load distributions were observed when the bone was subjected to a single vertical load of 1,000. N. Results: The longer the length of the implant flexion, which coincided with the working area of the plate, the greater the flexion of the implant. The highest concentrations of stress on the plate occurred in the region around the screws closest to the bone gap. The closer the screws to the fracture site, the greater the demands on the plate. Conclusion: When using a large-fragment titanium alloy locking plate to stabilize a simple transverse fracture based on the principle of relative stability (bridge plate), the distance between the proximal and distal screws closest to the fracture line must be long. The farther away this fixation is, the lower the stress on the plate and the greater the dissipation of force in the form of deflection. © 2017 Sociedade Brasileira de Ortopedia e Traumatologia

Finite Element Analysis Of The Equivalent Stress Distribution In Schanz Screws During The Use Of A Femoral Fracture Distractor

To evaluate the mechanical stress and elastic deformation exercised in the thread/shaft transition of Schanz screws in assemblies with different screw anchorage distances in the entrance to the bone cortex, through the distribution and location of tension in the samples.An analysis of 3. D finite elements was performed to evaluate the distribution of the equivalent stress (triple stress state) in a Schanz screw fixed bicortically and orthogonally to a tubular bone, using two mounting patterns: (1) thread/shaft transition located 20. mm from the anchorage of the Schanz screws in the entrance to the bone cortex and (2) thread/shaft transition located 3. mm from the anchorage of the Schanz screws in entrance to the bone cortex. The simulations were performed maintaining the same direction of loading and the same distance from the force vector in relation to the center of the hypothetical bone. The load applied, its direction, and the distance to the center of the bone were constant during the simulations in order to maintain the moment of flexion equally constant. The present calculations demonstrated linear behavior during the experiment. It was found that the model with a distance of 20. mm between the Schanz screws anchorage in the entrance to the bone cortex and the thread/shaft transition reduces the risk of breakage or fatigue of the material during the application of constant static loads; in this model. the maximum forces observed were higher (350. Mpa). The distance between the Schanz screws anchorage at the entrance to the bone cortex and the smooth thread/shaft transition of the screws used in a femoral distractor during acute distraction of a fracture must be farther from the entrance to the bone cortex, allowing greater degree of elastic deformation of the material, lower mechanical stress in the thread/shaft transition, and minimized breakage or fatigue. The suggested distance is 20. mm. © 2016 Sociedade Brasileira de Ortopedia e Traumatologia

Biomechanical and histological evaluation of hydrogel implants in articular cartilage

We evaluated the mechanical behavior of the repaired surfaces of defective articular cartilage in the intercondylar region of the rat femur after a hydrogel graft implant. The results were compared to those for the adjacent normal articular cartilage and for control surfaces where the defects remained empty. Hydrogel synthesized by blending poly(2-hydroxyethyl methacrylate) and poly(methyl methacrylate-co-acrylic acid) was implanted in male Wistar rats. The animals were divided into five groups with postoperative follow-up periods of 3, 5, 8, 12 and 16 weeks. Indentation tests were performed on the neoformed surfaces in the knee joint (with or without a hydrogel implant) and on adjacent articular cartilage in order to assess the mechanical properties of the newly formed surface. Kruskal-Wallis analysis indicated that the mechanical behavior of the neoformed surfaces was significantly different from that of normal cartilage. Histological analysis of the repaired defects showed that the hydrogel implant filled the defect with no signs of inflammation as it was well anchored to the surrounding tissues, resulting in a newly formed articular surface. In the case of empty control defects, osseous tissue grew inside the defects and fibrous tissue formed on the articular surface of the defects. The repaired surface of the hydrogel implant was more compliant than normal articular cartilage throughout the 16 weeks following the operation, whereas the fibrous tissue that formed postoperatively over the empty defect was stiffer than normal articular cartilage after 5 weeks. This stiffness started to decrease 16 weeks after the operation, probably due to tissue degeneration. Thus, from the biomechanical and histological point of view, the hydrogel implant improved the articular surface repair

Inflammatory Reaction Of Rat Striated Muscle To Particles Of Carbon Fiber Reinforced Carbon.

1. Carbon fiber reinforced carbon (CFRC) was implanted in rats as particles measuring 30 microns or 11 microns, denoted as CFRC-A and CFRC-B, respectively. Titanium (Ti) and vitreous carbon (VC) were used as controls. Ti was used with the same particle size as CFRC (Ti-A or Ti-B). The VC particles measured 11 microns. All materials were separately sterilized on ethylene oxide before use. 2. One hundred and ten female Wistar rats, weighing 180 to 220 g, were divided into six groups of 4 to 5 animals each, according the time of the observation (1, 2, 4, 8, 16 and 52 weeks). 3. Under aseptic conditions, one 3-0 curette full of CFRC-A or CFRC-B was implanted into the right triceps surae muscle in each animal and the same quantity of Ti-A (paired with CFRC-A) or Ti-B or VC (paired with CFRC-B) was implanted into the left muscle. 4. Histological analysis did not show necrosis of muscular tissue nor exudative reaction during the acute phase. 5. During the chronic phase the particles induced a chronic inflammatory infiltration containing fibroblasts, macrophages and giant cells. VC and CFRC-B induced the lowest inflammatory infiltration and CFRC-A induced the highest one. 6. We suggest that the longer carbon fiber fragments contained in CFRC-A may be responsible for this more intensive reaction, which may restrict the medical use of the preparation.26881982

Distal Radius Fractures: Consistency Of The Classifications [fraturas Do Rádio Distal: Avaliação Das Classificações.]

OBJECTIVE: The purpose of this study was to determine the intra-observer and interobserver reproducibility of Frykman, AO and Universal classifications for the fractures of the distal radius. METHODS: In this study, 40 radiographs of fractures of the distal radius were selected and classifed by orthopedists of different centers and levels of experience, determining the intra-observer and interobserver reproducibility of the classifications using Kappa statistic method. RESULTS: The medium intra-observer concordance observed was moderate to Frykman and Universal classifications and light to the AO system. The medium interobserver reproducibility was light in the two readings to Frykman and Universal classifications and despicable in the second reading of the AO classification. CONCLUSION: All the classifications used presented questionable interobserver reproducibility compromising the use of the three evaluated systems.501556