Vilmos Vécsei

The influence of scaffold architecture on chondrocyte distribution and behavior in matrix-associated chondrocyte transplantation grafts.

Scaffold architecture and composition are important parameters in cartilage tissue engineering. In this in vitro study, we compared the morphology of four different cell-graft systems applied in clinical cartilage regeneration and analyzed the cell distribution (DAPI nuclei staining) and cell-scaffold interaction (SEM, TEM). Our investigations revealed major differences in cell distribution related to scaffold density, pore size and architecture. Material composition influenced the quantity of autogenous matrix used for cellular adhesion. Cell bonding was further influenced by the geometry of the scaffold subunits. On scaffolds with widely spaced fibers and a thickness less than the cell diameter, chondrocytes surrounded the scaffold fibers with cell extensions. On those fibers, chondrocytes were spherical, suggesting a differentiated phenotype. Fiber sizes smaller than chondrocyte size, and widely spaced, are therefore beneficial in terms of improved adhesion by cell shape adaptation. They also support the differentiated stage of chondrocytes by preventing the fibroblast-like and polygonal cell shape, at least briefly.

Surgical treatment of dens fractures in elderly patients.

BACKGROUND A dens fracture is the most common cervical fracture in elderly patients. The purposes of this study were to analyze the functional and radiographic results after surgical treatment of dens fractures in patients over sixty-five years of age and to compare the two methods that were used for operative treatment. METHODS We reviewed the cases of fifty-six patients, with an average age of 71.4 years at the time of surgery, who had undergone surgical treatment of a dens fracture from 1988 to 2002. Thirty-seven fractures were stabilized with anterior screw fixation, and nineteen fractures had posterior cervical arthrodesis. RESULTS Forty-five patients returned to their preinjury activity level and were satisfied with their treatment. Thirty-five patients had a full range of neck movement, and forty-seven patients were free of pain. Technical failures occurred in eight patients. The thirty-seven patients treated with anterior screw fixation had a good clinical outcome, with fracture-healing in thirty-three patients (89%) and technical failure in five patients (14%). All nineteen patients treated with posterior cervical arthrodesis had fracture union, with technical failure in three patients, but the functional results were worse than those after anterior screw fixation. With the inclusion of the six patients who had been excluded from the clinical and radiographic review, the overall morbidity rate was 16% (ten of sixty-two patients) and the overall mortality rate was 6% (four of sixty-two patients). CONCLUSIONS A satisfactory outcome can be achieved with surgical treatment of a dens fracture in geriatric patients. It appears that anterior screw fixation may maintain better mobility of the cervical spine, but it appears to be associated with a higher rate of fracture nonunion and a greater potential for reoperation.

A new simplified technique for producing platelet-rich plasma: a short technical note

A possible strategy to promote the wound-healing cascade in both soft and hard tissues is the preparation of an autologous platelet-rich plasma (PRP) to encourage the release of growth factors from activated platelets. In this process, PRP combines the advantage of an autologous fibrin clot that will aid in hemostasis as well as provide growth factors in high concentrations to the site of a tissue defect. The PRP preparation can be used as a biological enhancer in the healing of fractures and lumbar fusions. The local application of growth factors seems to promote initiation and early maturation of bone formation. Autologous bone or bone substitutes can be added to this mixture to increase the volume of grafting material. A simplified technique utilizing a commercially available separation system (GPS—Gravitational Platelet Separation System) is described. This system provides a less costly alternative to other previously described augmentation techniques and also presents a patient-friendly and operator-safe alternative. Further experimental studies of the actual concentrations of the growth factors in the PRP samples are necessary in order to validate the platelet concentration and growth-factor activation by laboratory evidence. In further prospective clinical trials, the safety and efficacy of PRP, in combination with autologous bone or bone graft substitutes, must be evaluated.

Nonoperative management of odontoid fractures using a halothoracic vest.

OBJECTIVEDespite various reports in the literature, the appropriate treatment of Type II odontoid fractures remains controversial. Although there is an increasing tendency toward surgical treatment of these fractures in recent years, nonoperative treatment strategies are still regarded as a practicable method, particularly in elderly patients with significant comorbidities. One purpose of this study was to determine the functional and radiographic long-term results after rigid immobilization of Type II odontoid fractures using a halothoracic vest. The second aim was to present a case-control series of patients with nonunion of Type II odontoid fractures compared with patients with successful fracture healing to determine specific risk factors for failure of halo immobilization. METHODSWe reviewed the clinical and radiographic records of 90 patients with an average age of 69 years at the time of injury who had undergone nonoperative treatment of odontoid fractures using a halothoracic vest between 1988 and 2004. To identify potential risk factors for failure of halo fixation, patients were divided into “cases” and “controls.” Cases were defined as patients with nonfusion after halo immobilization, and controls were patients with successful fracture healing attained with this treatment option. RESULTSSeventy-five patients returned to their preinjury activity level and were satisfied with their treatment. The Smiley-Webster scale showed an overall functional outcome score of 1.64. Successful fracture healing was achieved in 76 patients (84%). In 14 patients, nonunion was diagnosed by standard x-rays and additional computed tomographic scans within 6 to 12 months after trauma. Referring to possible risk factors for failure of halo fixation, nonunion was found significantly more often in older patients and in those with displaced fractures of the odontoid. Secondary loss of reduction and delay of treatment were identified as further risk factors for nonfusion. CONCLUSIONWith regard to successful fracture healing and functional results of the patients, we had a satisfactory outcome after halo fixation of Type II odontoid fractures. Although a fusion rate of 84% should not be deemed as optimal, nonoperative management of these fractures using a halothoracic vest seems to be an appropriate treatment strategy in patients who are not suitable for surgical treatment.

VEGF serum concentrations in patients with long bone fractures: A comparison between impaired and normal fracture healing

Vascular endothelial growth factor (VEGF) plays an important role in the bone repair process as a potent mediator of angiogenesis and it influences directly osteoblast differentiation. Inhibiting VEGF suppresses angiogenesis and callus mineralization in animals. However, no data exist so far on systemic expression of VEGF with regard to delayed or failed fracture healing in humans. One hundred fourteen patients with long bone fractures were included in the study. Serum samples were collected over a period of 6 months following a standardized time schedule. VEGF serum concentrations were measured. Patients were assigned to one of two groups according to their course of fracture healing. The first group contained 103 patients with physiological fracture healing. Eleven patients with delayed or nonunions formed the second group of the study. In addition, 33 healthy volunteers served as controls. An increase of VEGF serum concentration within the first 2 weeks after fracture in both groups with a following decrease within 6 months after trauma was observed. Serum VEGF concentrations in patients with impaired fracture healing were higher compared to the patients with physiological healing during the entire observation period. However, statistically significant differences were not observed at any time point between both groups. VEGF concentrations in both groups were significantly higher than those in controls. The present results show significantly elevated serum concentrations of VEGF in patients after fracture of long bones especially at the initial healing phase, indicating the importance of VEGF in the process of fracture healing in humans.

Management and outcome of interprosthetic femoral fractures.

INTRODUCTION Interprosthetic femoral fractures following ipsilateral hip and knee arthroplasty are a rare but serious complication in clinical practice. In most cases, adequate management of these injuries might constitute a challenging problem. However, the literature provides only few data regarding the treatment and outcome of interprosthetic femoral fractures, and there are only few classifications available, which might assist in finding an appropriate treatment concept. The purpose of this study was to analyse our experience in the management of interprosthetic femoral fractures following ipsilateral hip and knee joint replacement. MATERIALS AND METHODS We reviewed the clinical and radiographic records of 23 patients (15 female and eight male, average age: 79.2 years) with an interprosthetic fracture after ipsilateral hip and knee joint replacement between 1992 and 2008. For the classification of interprosthetic femoral fractures, the fractures were divided into three types, depending on the fracture site and the adjacency to the prostheses. All patients underwent operative stabilisation, either by lateral plate fixation (n=19), by revision arthroplasty using a long stem (n=2) or by plate fixation and revision arthroplasty (n=2). RESULTS Referring to the clinical outcome, 16 patients returned to their pre-injury activity level and were satisfied with their clinical outcome. In six patients, we saw a relevant decrease of hip or knee function and severe limitations in gait and activities of daily living. We had a mean Harris Hip Score (HHS) of 78.4 points, and a mean Knee injury and Osteoarthritis Outcome Score (KOOS) of 71.8 points. Relating to the radiographic outcome, successful fracture healing was achieved in 19 of 22 patients (86%) within 6 months. Failures of reduction and fixation were noted in four (18%) of 22 patients. CONCLUSION We had a satisfactory outcome following individualised treatment of interprosthetic femoral fractures following ipsilateral hip and knee joint replacement. Compared to the rare data in current literature, we had promising functional result and high rate of bony fusion. Regarding the complexity and challenges in many of these cases, interprosthetic fractures require an adequate analysis of the fracture aetiology and a suitable transfer into the best possible treatment concept.

Clinical outcome after microfracture of the knee: a meta-analysis of before/after-data of controlled studies

PurposeThe aims of this study were to systematically review the medical literature, in order to find controlled studies about microfracture in the treatment of patients with full-thickness cartilage lesions of the knee, to statistically combine these studies in order to determine a best estimate of the average treatment effect, and to gather information to detect cartilage-specific and patient-specific factors that might have an influence on the clinical outcome.MethodsWe searched four electronic databases for controlled clinical trials or controlled prospective observational studies. We pooled before/after-data of study arms using the term microfracture.ResultsWe calculated an overall best estimate of 1.106, with [0.566; 1.646] as 95% confidence interval of the mean standardized treatment effect for a representative patient population.ConclusionsOur meta-analysis revealed a clinically relevant improvement of the postoperative clinical status as compared to the preoperative status. An increase of 22 overall KOOS points may provide a rough estimate for the mean expected treatment effect achieved by microfracturing.

Elevated levels of macrophage colony‐stimulating factor in human fracture healing

Macrophage colony‐stimulating factor (M‐CSF) plays a unique role in bone remodeling. However, to our knowledge, no data on the role of M‐CSF in fracture healing in humans have been published so far. This study addressed this issue. One hundred and thirteen patients with long‐bone fractures were included in the study and divided into two groups, according to their course of fracture healing. The first group contained 103 patients with normal fracture healing. Ten patients with impaired fracture healing formed the second group of the study. Volunteers donated blood samples as control. Serum samples were collected over a period of 6 months, following a standardized time schedule. In addition, M‐CSF levels were measured in fracture hematoma and serum of 11 patients with bone fractures. M‐CSF concentrations were measured by enzyme‐linked immunosorbent assay (ELISA). Fracture hematoma contained significantly higher M‐CSF concentrations compared to M‐CSF concentrations in patients serum. M‐CSF levels in fracture hematoma and in patients serum were both significantly higher than M‐CSF concentrations measured in serum of healthy controls. Highly elevated M‐CSF serum concentrations were found in patients with physiological fracture healing over the entire observation period. Significant differences in the M‐CSF serum concentration between patients with normal fracture healing and patients with impaired fracture healing were not observed. This study indicates, for the first time, to our knowledge, a possible local and systemic involvement of M‐CSF in humans during fracture healing.

The impact of colony-stimulating factor-1 on fracture healing: an experimental study.

The role of colony stimulating factor‐1 (CSF‐1) in the regulation of osteoclasts and bone remodeling suggests that CSF‐1 may also be involved in regulation of bone healing. The ability of CSF‐1 to promote healing of bone defects was tested in a rabbit model. Twenty‐four New Zeeland rabbits were included in the study. Animals were assigned to two groups: the control group (n = 12) was treated by plate fixation. The animals in the second group (n = 12) were also stabilized by conventional plating and received additionally CSF‐1 for 2 weeks systemically. Histologic, histomorphometric, and radiologic examinations were performed to evaluate the healing process at 4, 8, and 12 weeks following surgery. Animals that were treated by CSF‐1 produced a significantly higher amount of mineralized bone over the first 8 weeks after fracture compared to the control animals. Furthermore, a higher number of osteoclasts was found in CSF‐1‐treated animals within the first 8 weeks, compared to the controls. The present data emphasize for the first time the importance of CSF‐1 in the bone healing. The use of CSF‐1 in addition to conventional fixation might be a novel approach for the treatment of bone defects.

Combination of anorganic bovine‐derived hydroxyapatite with binding peptide does not enhance bone healing in a critical‐size defect in a rabbit model

Anorganic bovine‐derived hydroxyapatite (ABM) in combination with binding peptid (P‐15) has demonstrated the capacity to improve the healing of periodontal defects. This study evaluated the benefit of ABM/P‐15 to promote healing of cortical long bone defects in a rabbit model. A 5‐mm segmental bone defect was created in the femur and fixed with a plate. There were two treatment groups: no implant (n = 12) and ABM/P‐15 (n = 12). At 4, 8, and 12 weeks, healing of the defect was evaluated with radiographs and histomorphometric examination of the treated femora. After 4 weeks, radiographs showed bone formation without signs of complete consolidation in three of four animals in the control group and two of four ABM/P‐15 treated animals. At the later course of the treatment, no radiologic difference was evident between the treatment groups. Histomorphometric evaluation revealed an area of 1.29 ± 0.11 mm2 and 0.97 ± 0.21 mm2 of newly produced bone in animals of the control group and ABM/P‐15 group after 4 weeks. After 8 and 12 weeks, animals in the control group had an area of 2.44 ± 0.62 mm2 and 2.5 ± 0.2 mm2 of newly produced bone within the osteotomy gap compared to 1.6 ± 0.65 mm2 and 1.56 ± 0.27 mm2 in the ABM/P‐15 group (p = 0.0004). An enhanced or accelerated ingrowth of bone, as reported in previous studies, was not observed. Our results imply that the ABM/P‐15 is not a suitable graft for the treatment of critical‐sized segmental defects in long bones.