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Abstract Human bone marrow-derived stem cells (hBMSCs) and adipose-derived stem cells (hASCs) have been used to regenerate bone. Both sources are claimed to have comparable osteogenic potential, but few comparative studies are available. Third-generation biomaterials have been developed to reduce steps in regenerating tissues. For osteogenesis gelatin/[beta]-tricalcium phosphate ([beta]-TCP) scaffolds with incorporated controlled-release bone morphogenetic protein-2 (BMP-2) as third-generation biomaterials were recently developed. So far, few studies on protein-induced osteogenesis versus chemical-induced osteogenesis have been performed. This study evaluates the osteogenic potential of hBMSCs versus hASCs derived on gelatin/[beta]-TCP scaffolds in vitro under four different conditions. Gelatin/[beta]-TCP scaffolds with and without incorporated controlled-release BMP-2 were seeded with hBMSCs or hASCs under oscillating fluid conditions in osteogenic (OS) medium or growth medium (GM). All were evaluated radiologically (computed tomography [CT] scan), histologically, biomechanically, and for gene expression at 1, 2, 4, and 6 weeks. The highest radiological densities were seen in specimens at 6 weeks with controlled-release BMP-2, close to native bone. HBMSCs, hASCs, OS, and GM conditions resulted in similar bone formation with gelatin/[beta]-TCP scaffolds and incorporated controlled-release BMP-2. This was confirmed histologically by Toluidine Blue and van Kossa staining and biomechanically. Gene expression studies of these specimens showed the presence of preosteoblasts, transitory osteoblasts, and secretory osteoblasts. Specimens comprised of gelatin/[beta]-TCP scaffolds without incorporated controlled release BMP-2 in OS medium showed lesser bone formation. hASCs and hBMSCs have similar osteogenic potential. hASCs are an attractive alternative to hBMSCs for bone regeneration using third-generation gelatin/[beta]-TCP scaffolds with incorporated controlled-release BMP-2. [ABSTRACT FROM AUTHOR]

Abstract Background Laser-Doppler imaging (LDI) of cutaneous blood flow is beginning to be used by burn surgeons to predict the healing time of burn wounds; predicted healing time is used to determine wound treatment as either dressings or surgery. In this paper, we do a statistical analysis of the performance of the technique. Methods We used data from a study carried out by five burn centers: LDI was done once between days 2 to 5 post burn, and healing was assessed at both 14 days and 21 days post burn. Random-effects ordinal logistic regression and other models such as the continuation ratio model were used to model healing-time as a function of the LDI data, and of demographic and wound history variables. Statistical methods were also used to study the false-color palette, which enables the laser-Doppler imager to be used by clinicians as a decision-support tool. Results Overall performance is that diagnoses are over 90% correct. Related questions addressed were what was the best blood flow summary statistic and whether, given the blood flow measurements, demographic and observational variables had any additional predictive power (age, sex, race, % total body surface area burned (%TBSA), site and cause of burn, day of LDI scan, burn center). It was found that mean laser-Doppler flux over a wound area was the best statistic, and that, given the same mean flux, women recover slightly more slowly than men. Further, the likely degradation in predictive performance on moving to a patient group with larger %TBSA than those in the data sample was studied, and shown to be small. Conclusion Modeling healing time is a complex statistical problem, with random effects due to multiple burn areas per individual, and censoring caused by patients missing hospital visits and undergoing surgery. This analysis applies state-of-the art statistical methods such as the bootstrap and permutation tests to a medical problem of topical interest. New medical findings are that age and %TBSA are not important predictors of healing time when the LDI results are known, whereas gender does influence recovery time, even when blood flow is controlled for. The conclusion regarding the palette is that an optimum three-color palette can be chosen 'automatically', but the optimum choice of a 5-color palette cannot be made solely by optimizing the percentage of correct diagnoses.

Background: Mortality in burn patients has several contributing factors as sex, age, degree of burns, or inhalation injuries. Usefulness of Candida antigen (CAG) titer is still being under debate to predict mortality. This study assessed correlation between CAG titer and mortality in burn patients., Methods: From 1988 to 2011, 877 burn intensive care patients were evaluated for age, sex, total burn surface area (TBSA), multi organ failure (MOF), burn depth, escharotomy, fasciotomy, antibiotic use, co-morbidities, CAG titer and intubation., Results: From 870 admitted patients, 190 patients were not enrolled. Increasing age was correlated with a higher mortality. The abbreviated burn severity index (ABSI) score of the deceased was 4 points and the TBSA was 20% higher than the survivors. The correlation for age, intubation, TBSA, inhalation injury, MOF, CAG titer, antibiotic use and escharotomy was significant. An increasing mortality was noted with antibiotic use and a CAG titer of 1:8 and higher. CAG titer of 1:8 and higher had a sensitivity of 51.1% and specificity of 86.3% for mortality. Multivariate analysis confirmed high influence of older age, MOF, comorbidities, antibiotic use and CAG titer of 1:8 and higher on mortality. There was a significant correlation for sex, younger age and CAG titer., Conclusion: CAG titers of 1:8 and higher might warrant beginning of antimycotic treatment in elderly patients with high TBSA to avoid increase in mortality., Competing Interests: The authors declare no conflict of interest.

Background: With the aim of improving component alignment and outcome in total knee arthroplasty (TKA), several computer-assisted devices (CAD) have been developed., Methods: In February 2014, the present unit started to use a new imageless navigation system with accelerometric pods within the surgical field for all primary TKAs; there was no need for optical trackers or cameras. This paper presents the results of the first 72 TKAs using this iAssist system in 71 prospectively collected and retrospectively analyzed patients. It analyzed component positioning in standard and full-length leg x-rays., Results: The mean age of the patients was 70years (range 52-88). The center of hip, knee and ankle (mechanical axes) deviated on average 0.5° (standard deviation (SD) of 1.8) valgus from the targeted straight alignment. Three TKAs had >3° deviation (i.e. four degree varus, five degree and seven degree valgus). The frontal tibial tray alignment was an average of 89.9° (range 86.4-100.1°, SD ±2.0) with the target being 90°, and the sagittal slope was as targeted at 85.0° (range 78.4-88.8°, SD ±1.7)., Conclusions: This CAD facilitated good mechanical alignment and reproducible accuracy in component positioning. Pods clipped onto cutting jigs within the surgical field provided simple and accurate navigation, with little extra time needed for calibration and no need for optical trackers or pre-operative imaging., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Various creams are available for superficial second-degree burns (SSDB) of the face. We evaluated provitamin pantothenic acid versus β-glucan for SSDB of the face using the O2C laser Doppler system and digital photo analysis. Out of 20 patients (January to December 2012) with facial burns, 7 with SSDB of both cheeks were included to our study. Burned cheek wounds were treated using pantothenic acid or β-glucan. Digital photos of marked regions were taken daily from predefined distances. Microcirculation was measured at marked regions for 7 days at scheduled time points using the O2C laser Doppler. Data were evaluated using the SPSS program (SPSS Inc., Chicago, IL). Wounds treated with β-glucan showed faster reepithelialization. O2C laser Doppler measurements showed faster increase in SO2, microvascular perfusion, hemoglobin content, and blood flow. This correlated good with clinical Vancouver Scar Scale results. Although not statistically significant, β-glucan cream therapy of SSDB results in aesthetically superior outcome and faster reepithelialization., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Background: Adequate biomaterials for tissue engineering bone and replacement of bone in clinical settings are still being developed. Previously, the combination of mesenchymal stem cells in hydrogels and calcium-based biomaterials in both in vitro and in vivo experiments has shown promising results. However, results may be optimized by careful selection of the material combination., Methods: β-Tricalcium phosphate scaffolds were three-dimensionally printed with five different hydrogels: collagen I, gelatin, fibrin glue, alginate, and Pluronic F-127. The scaffolds had eight channels, running throughout the entire scaffold, and macropores. Mesenchymal stem cells (2 × 10) were mixed with each hydrogel, and cell/hydrogel mixes were dispersed onto the corresponding β-tricalcium phosphate/hydrogel scaffold and cultured under dynamic-oscillating conditions for 6 weeks. Specimens were harvested at 1, 2, 4, and 6 weeks and evaluated histologically, radiologically, biomechanically and, at 6 weeks, for expression of bone-specific proteins by reverse-transcriptase polymerase chain reaction. Statistical correlation analysis was performed between radiologic densities in Hounsfield units and biomechanical stiffness., Results: Collagen I samples had superior bone formation at 6 weeks as demonstrated by volume computed tomographic scanning, with densities of 300 HU, similar to native bone, and the highest compression values. Bone specificity of new tissue was confirmed histologically and by the expression of alkaline phosphatase, osteonectin, osteopontin, and osteocalcin. The bone density correlated closely with histologic and biomechanical testing results., Conclusion: Bone formation is supported best by β-tricalcium phosphate/collagen I hydrogel and mesenchymal stem cells in collagen I hydrogel., Clinical Question/level of Evidence: Therapeutic, V.

Background: The fingertip is the most commonly injured part of the hand and is an important aesthetic part of the hand., Methods: In this retrospective study we analyzed data from 700 patients operated on between 1997 and 2008 for complications after nail splinting with native nail or silicone nail. Inclusion criteria were patients living in Bern/Berner Land, complete documentation, same surgical team, standard antibiotics, acute trauma, no nail bed transplantation, and no systemic diseases. Groups were analyzed for differences in age, gender, cause and extension of trauma, bony injury and extent, infection, infectious agent, and nail deformities. Statistical analysis was done using the χ (2) test, Fisher's exact test, and Pearson correlation coefficients., Results: A total of 401 patients, with a median age of 39.5 years, were included. There were more men with injured nails. Two hundred forty native nails and 161 silicone splints were used. There were 344 compression injuries, 44 amputations, and 13 avulsion injuries. Forty-three patients had an infection, with gram-positive bacteria (Staphylococcus aureus) causing most infections. A total of 157 nail dystrophies were observed, split nails most often. The native nail splint group showed significantly (p < 0.015) fewer nail deformities than the silicone nail splint group; otherwise, there were no statistical differences. However, there were twice as many infections in the silicone nail group., Conclusion: It seems to be advantageous to use the native nail for splinting after trauma, when possible. In case of a destroyed and unusable nail plate, a nail substitute has to be used.

Patients with sternum osteomyelitis are transferred to plastic surgery departments for wound coverage. Several options of flap coverage are known; however, various wound diameters need different flaps. In a retrospective study, 135 patients from 2006-2010 with deep sternal wound infections were evaluated. From 2006-2009 various flaps were used for wound coverage, as described in published reports. In 2010 a developed algorithm was used for defect coverage based on wound width using pectoralis muscle flaps or the latissimus dorsi muscle flap. Two groups of patients were analyzed, from 2006-2009 and 2010, and in a matched pair analysis patients with small wound width less than 6 cm, medium wounds widths between 6-12 cm, and large wound width larger than 12 cm. End-point was wound dehiscence larger than 1 cm. Statistical analysis was done by Mann Whitney U-test using the SPSS program. Forty-eight patients were included in the match from a total of 130 study patients. Statistical analysis did not show significant difference in patient population of the two groups. In the group with wound sizes less than 6 cm a significant difference was found when using the algorithm. In the other groups no statistically significant difference was seen; however lesser numbers in wound dehiscence were found. In addition, a significantly lesser length of stay was found in the ICU and length of the hospital stay for all groups treated according to the algorithm. A reduction of costs may be achieved when using the algorithm based on wound size.

Objective: To analyze trends in incidence and treatment of thermal injuries over the last two decades., Methods: We retrospectively reviewed our local single center database of patients with thermal injuries admitted to the burn intensive care unit (BICU) of the Cologne-Merheim Medical Center (University Hospital of Witten/Herdecke). The cohort was divided into two groups according to the decade of admission and the epidemiology and clinical course of the patient sample admitted during the period 1991-2000 (n=911) was compared to that of 2001-2010 (n=695)., Results: The following variables were significantly different in the bivariate analysis: mean age (39.8 years vs. 44.0 years), burn size of total body surface area (23.2% vs. 18.0%) and size of 3rd degree burns (9.6% vs. 14.9%). The incidence of inhalation injury was significantly lower in the last decade (33.3% vs. 13.7%) and was associated with a shorter duration of mechanical ventilation (10.8 days vs. 8.5 days). The ABSI-score as an indicator of burn severity declined in the second period (6.3 vs. 6.0) contributing partially to the decline of BICU length of stay (19.1 days vs. 18.8 days) and to the mortality rate decrease (18.6% vs. 15.0%)., Conclusion: The severity of burn injuries during the last two decades declined, probably reflecting the success of prevention campaigns. Concerning mortality, the chance of dying for a given severity of injury has decreased., (Copyright © 2012 Elsevier Ltd and ISBI. All rights reserved.)

Background: Patients transferred to Plastic Surgery Departments for sternum osteomyelitis have a high morbidity of about 3%. Despite several known options for sternal wound coverage and salvage operations, wound dehiscence or wound necrosis can occur, increasing patient morbidity., Patients and Methods: One hundred thirty-five patients admitted between January 2007 and December 2010 were evaluated in a retrospective study for wound dehiscence after salvage wound coverage at our institution. Various flaps were applied, such as pectoralis major myocutaneous pedicled flaps, pectoralis major muscle pedicled flaps, latissimus dorsi pedicled flaps, greater omental flaps, and vertical rectus abdominis muscle and transverse rectus abdominis muscle flaps. Inclusion criteria were sternal wound infection, bacterial wound infection, previous wound debridement outside our institution, vacuum-assisted closure device wound treatment at our institution, and secondary flap closure of the sternal defect at our institution. A multivariate regression analysis was performed., Results: One hundred thirty patients met the inclusion criteria. In all patients, bacterial wound colonization was shown. Forty patients showed wound dehiscence after closure at our institution. Reasons for wound dehiscence were attributed to wound size, >4 different species of bacteria colonizing the wound, gram-negative bacteria, Candida albicans, intensive care unit stay, and female gender. Interestingly, wound dehiscence was not significant correlated to obesity, smoking, atherosclerosis, renal insufficiency or type of closure influenced significantly, or necrosis., Conclusions: Female patients after CABG, with large sternal wounds infected with gram-negative bacteria and candida, have an 85% risk of wound dehiscence after flap coverage for sternal wound infection.

Digital finger amputation with soft tissue injury is a frequent accident in reconstructive surgery. Several techniques about reconstruction of digital finger amputation are described in literature. However replantation is difficult when large segments of the arteries are missing. This is especially true for distal finger phalanx amputations, where replantation is done in selected patients such as artists or musicians. In this article a microsurgical replantation techniques of a distal artery and proximal vein anastomosis is presented in a distal phalanx amputation, which successfully solved the problem of venous reflux without venous anastomosis.

In recurrent pressure sores, adjacent tissue has already been consumed by multiple surgeries. Additional problems are several co-morbidities of patients. Especially, severe atherosclerosis would be a contraindication for using free flaps. However, microsurgical techniques allow circumventing these limitations and preparing even severely atherosclerotic vessels. We performed a total of eight sacral pressure sore coverage in our standardized fashion, using the free combined latissimus dorsi and serratus anterior free flaps. All patients had severe atherosclerosis and needed large soft tissue coverage of the sacral defects. Five patients presented after bowel resection, three with recurrent sacral pressure sores. The average follow-up was 12 months. Postoperatively, all patients were allowed to be prone on the operated area. One minor wound dehiscence was sutured in local anesthesia. CT imaging analysis of the pelvis showed complete void space coverage. The combined latissimus dorsi and serratus anterior flaps are a valuable tool for pelvic reconstruction in our hands. In addition, severe atherosclerosis should not be considered an obstacle to microsurgery and the use of free flaps., (Copyright © 2011 Wiley-Liss, Inc.)

Self-immolation constitutes a rare form of suicide in developed countries, though it accounts for unique injury characteristics in the burn intensive care unit. The aim of this study was to present the epidemiological and clinical features of patients burned during a suicidal attempt seen in a North Rhine-Westphalia burn intensive care unit (BICU). To address this aim, we undertook a 21-year retrospective study involving patients with thermal injuries admitted to the largest burn unit in Germany. A total of 125 suicide-related burn victims were identified in the study period (9.4%). Comparing the self-immolation group with the rest burn patient cohort, suicide victims were more likely to be single and to act under the influence of alcohol. The suicidal group had a larger extent of burns, higher incidence of inhalation injury, required more surgical procedures, catecholamines, blood transfusions, and a longer BICU stay. Their clinical course was complicated by prolonged intubation period, higher rate of multiple drug-resistant bacteria acquisition and sepsis, leading to a higher mortality rate. Although the proportion of self-immolation victims among all burned patients is not high, the markedly higher severity of their burns and their poorer quality of outcomes makes them an important clinical subgroup for further study.

Seeding cells efficiently and uniformly onto three-dimensional scaffolds is a key element for engineering tissues, particularly when only a low-number of cells is available for tissue repair and regeneration. The aim of this study was to evaluate three seeding techniques on two biocompatible scaffolds in vitro using chondrocytes as follows: (1) static; (2) modified centrifugal cell immobilization (CCI); and (3) dynamic oscillating motion. Five milliliters of media containing 5, 10, or 25 million articular, auricular, or costal chondrocytes were used to seed porous PLGA scaffolds and sections of devitalized cartilage. The dynamic oscillating technique resulted in up to 150% higher cellular load at 7 days than CCI seeding. Cell distribution was more homogeneous throughout the scaffold under dynamic conditions versus more sporadic and dispersed cell concentrations on the scaffolds when using either the static or the modified CCI technique. Cell load and distribution, when using a low numbers of chondrocytes at one and two million cells per milliliter, was comparable to that using the much higher number, especially under dynamic seeding conditions. The seeded scaffolds were used as implants to achieve cellular bonding between two devitalized meniscus discs. The constructs were implanted subcutaneously in nude mice for 12 weeks and analyzed histologically. Implants seeded with auricular chondrocytes showed qualitative more integration into native meniscus tissue than articular and costal cell implants. We conclude the dynamic oscillating seeding technique is an efficient technique for seeding low-cell numbers onto scaffolds resulting in consistent and uniform cell distribution throughout porous PLGA scaffolds., ((c) 2009 Wiley Periodicals, Inc.)

Regenerative technology promises to alleviate the problem of limited donor supply for bone or organ transplants. Most expensive and time consuming is cell expansion in laboratories. We propose a method of magnetically enriched osteoprogenitor stem cells, dispersed in self-assembling hydrogels and applied onto new ultra-high resolution, jet-based, three-dimensional printing of living human bone in a single-step for in situ bone regeneration. Human bone marrow-derived mesenchymal stem cells (hBMSCs) were enriched with CD 117+ cells, dispersed in different collagen I and RAD 16I hydrogel mixes, and applied onto three-dimensional printed btricalcium phosphate=poly(lactic-co-glycolic acid) scaffolds, printed from ultra-high-resolution volumetric CT images of a human thumb. Constructs were directly implanted subcutaneously into nude mice for 6 weeks. In vivo radiographic volumetric CT scanning and histological evaluations were performed at 1, 2, 4, and 6 weeks, and expression of bone-specific genes and biomechanical compression testing at 6 weeks endpoint. Time-dependant accumulation of bone-like extracellular matrix was most evident in CD 117+ hBMSCs using collagen I=RAD 16I hydrogel mix. This was shown histologically by Toluidine blue, von Kossa, and alkaline phosphatase staining, paralleled by increased radiological densities within implants approximating that of human bone, and confirmed by high expression of bone-specific osteonectin and biomechanical stiffness at 6 weeks. Human origin of newly formed tissue was established by expression of human GAPDH using RT-PCR. Statistical analysis confirmed high correlations between biomechanical stiffness, radiological densities, and bone markers. Bone tissue can be successfully regenerated in vivo using a single-step procedure with constructs composed of RAD 16I=collagen I hydrogel, CD 117+-enriched hBMSCs, and porous b-tricalcium phosphate=poly(lactic-co-glycolic acid) scaffolds.

Background: Laser-Doppler imaging (LDI) of cutaneous blood flow is beginning to be used by burn surgeons to predict the healing time of burn wounds; predicted healing time is used to determine wound treatment as either dressings or surgery. In this paper, we do a statistical analysis of the performance of the technique., Methods: We used data from a study carried out by five burn centers: LDI was done once between days 2 to 5 post burn, and healing was assessed at both 14 days and 21 days post burn. Random-effects ordinal logistic regression and other models such as the continuation ratio model were used to model healing-time as a function of the LDI data, and of demographic and wound history variables. Statistical methods were also used to study the false-color palette, which enables the laser-Doppler imager to be used by clinicians as a decision-support tool., Results: Overall performance is that diagnoses are over 90% correct. Related questions addressed were what was the best blood flow summary statistic and whether, given the blood flow measurements, demographic and observational variables had any additional predictive power (age, sex, race, % total body surface area burned (%TBSA), site and cause of burn, day of LDI scan, burn center). It was found that mean laser-Doppler flux over a wound area was the best statistic, and that, given the same mean flux, women recover slightly more slowly than men. Further, the likely degradation in predictive performance on moving to a patient group with larger %TBSA than those in the data sample was studied, and shown to be small., Conclusion: Modeling healing time is a complex statistical problem, with random effects due to multiple burn areas per individual, and censoring caused by patients missing hospital visits and undergoing surgery. This analysis applies state-of-the art statistical methods such as the bootstrap and permutation tests to a medical problem of topical interest. New medical findings are that age and %TBSA are not important predictors of healing time when the LDI results are known, whereas gender does influence recovery time, even when blood flow is controlled for.The conclusion regarding the palette is that an optimum three-color palette can be chosen 'automatically', but the optimum choice of a 5-color palette cannot be made solely by optimizing the percentage of correct diagnoses.

Traumatic amputation of a thumb with bone loss leaves a patient in severe disability. Reconstructive procedures are restricted by limited shape and have the disadvantage of severe donor-site morbidity. To overcome these limitations, we used a tissue engineering approach to create a distal thumb bone phalanx, combining magnetically sorted 133+ human mesenchymal stem cells (hMSCs) suspended in successful tested hydrogels for bone formation and porous 3-dimensionally printed scaffolds (3DP) in the shape of a distal thumb bone phalanx. Collagen I and fibrin glue hydrogels with suspended hMSCs were first histologically evaluated in vitro for bone formation after 6 weeks. Then 3DP scaffolds, made from a mix of osteoinductive and -conductive beta-tricalciumphosphate (beta-TCP) and poly-epsilon-caprolactone (PCL), with hydrogels and suspended hMSCs, were implanted into nude mice subcutaneously for 15 weeks. Histologic evaluation, high-resolution volumetric CT (VCT) scanning, and biomechanical testing confirmed formation of bonelike tissue. Both hydrogels with CD 133+ hMSCs on 3DP scaffolds supported bone formation. Collagen I resulted in radiologically better bone formation. Bone tissue can be successfully tissue engineered with CD 133+ hMSCs, collagen I hydrogels, and porous 3DP beta-TCP/PCL scaffolds.

Availability of grafts and morbidity at the donor site limit autologous transplantation in patients requiring bone reconstruction. A tissue-engineering approach can overcome these limitations by producing bone-like tissue of custom shape and size from isolated cells. Several hydrogels facilitate osteogenesis on porous scaffolds; however, the relative suitability of various hydrogels has not been rigorously assessed. Fibrin glue, alginate, and collagen I hydrogels were mixed with swine bone marrow-derived differentiated mesenchymal stem cells (MSCs), applied to 3-dimensionally printed porous beta-tricalcium phosphate (beta-TCP) scaffolds and implanted subcutaneously in nude mice. Although noninvasive assessment of osteogenesis in 3 dimensions is desirable for monitoring new bone formation in vivo, correlations with traditional histological and mechanical testing need to be established. High-resolution volumetric computed tomography (VCT) scanning, histological examination, biomechanical compression testing, and osteonectin (ON) expression were performed on excised scaffolds after 1, 2, 4, and 6 weeks of subcutaneous implantation in mice. Statistical correlation analyses were performed between radiological density, stiffness, and ON expression. Use of collagen I as a hydrogel carrier produced superior bone formation at 6 weeks, as demonstrated using VCT scanning with densities similar to native bone and the highest compression values. Continued contribution of the seeded MSCs was demonstrated using swine-specific messenger ribonucleic acid probes. Radiological density values correlated closely with the results of histological and biomechanical testing and ON expression. High-resolution VCT is a promising method for monitoring osteogenesis.

Background: Meniscal tears in the avascular zones do not heal. Although tissue-engineering approaches using cells seeded onto scaffolds could expand the indication for meniscal repair, harvesting autologous cells could cause additional trauma to the patient. Allogenic cells, however, could provide an unlimited amount of cells., Hypothesis: Allogenic cells from 2 anatomical sources can repair lesions in the avascular region of the meniscus., Study Design: Controlled laboratory study., Methods: Both autologous and allogenic chondrocytes were seeded onto a Vicryl mesh scaffold and sutured into a bucket-handle lesion created in the medial menisci of 17 swine. Controls consisted of 3 swine knees treated with unseeded implants and controls from a previous experiment in which 4 swine were treated with suture only and 4 with no treatment. Menisci were harvested after 12 weeks and evaluated histologically for new tissue and percentage of interface healing surface; they were also evaluated statistically., Results: The lesions were closed in 15 of 17 menisci. None of the control samples demonstrated healing. Histologic analysis of sequential cuts through the lesion showed formation of new scar-like tissue in all experimental samples. One of 8 menisci was completely healed in the allogenic group and 2 of 9 in the autologous group; the remaining samples were partially healed in both groups. No statistically significant differences in the percentage of healing were observed between the autologous and allogenic cell-based implants., Conclusion: Use of autologous and allogenic chondrocytes delivered via a biodegradable mesh enhanced healing of avascular meniscal lesions., Clinical Relevance: This study demonstrates the potential of a tissue-engineered cellular repair of the meniscus using autologous and allogenic chondrocytes.

Unlabelled: Successful treatment of tears to the avascular region of the meniscus remains a challenge. Current repair techniques, such as sutures and anchors, are effective in stabilizing the peripheral, vascularized regions of the meniscus, but are not adequate for promoting healing in the avascular region. The purpose of this study was to demonstrate the healing ability of a tissue-engineered repair technique using allogenic chondrocytes from three different sources for the avascular zone of the meniscus., Material and Methods: Articular, auricular, and costal chondrocytes were harvested from 3-month-old Yorkshire swine. A 1-cm bucket-handle lesion was created in the avascular zone of each three swine. A cell-scaffold construct, composed of a single chondrocyte cell type and Vicryl mesh, was implanted into the lesion and secured with two vertical mattress sutures. Controls consisted of each three sutured unseeded mesh implants, suture only, and untreated lesions. The swine were allowed immediate post-operative full weight bearing. Menisci and controls were harvested after 12 weeks., Results: In all experimental samples, lesion closure was observed. Gross mechanical testing with two Adson forceps demonstrated bonding of the lesion. Histological analysis showed formation of new tissue in all three experimental samples. None of the control samples demonstrated closure and formation of new matrix., Conclusion: We present preliminary data that demonstrates the potential of a tissue-engineered, allogenic cellular repair to provide successful healing of lesions in the avascular zone in a large animal model.