Epiphyseal fixation in revision total knee arthroplasty: a comparison between trabecular metal and titanium augments.

INTRODUCTION: The purpose of this retrospective study was to compare the medium-term clinical and radiographic outcomes of two series of patients treated for revision TKA: one implanted with trabecular metal (TM) augments and one implanted with classic titanium augments. MATERIALS AND METHODS: A total of 85 patients with a type 2 AORI defect underwent revision TKA and were treated either with TM epiphyseal augments directly screwed in the bone or with traditional titanium augments. There were 46 patients in the TM group and 39 patients in the titanium group included in the study. All the patients received the same varus-valgus constrained implant and no metaphyseal fixation devices were used. RESULTS: After a mean follow-up of 66.4 months, no statistically significant difference was observed in terms of failure for aseptic loosening between the two groups (4% in the TM group and 7.8% in the titanium group, p = 0.35). The ten-year survival using aseptic loosening as endpoint was 90.5% (95% CI 94.1-98.6) in the TM group and 85% (95% CI 101.9-119.3) in the titanium group (p = 0.26). A statistically significant difference was detected for the presence of RLL. No RLL were found under the studied TM augments compared to 13.7% of the titanium augments (p = 0.01). CONCLUSION: The use of TM augments directly screwed to the epiphysis of the femur and the tibia reduced the incidence of RLL compared to standard titanium augments during revision TKA with promising medium-term results.

Monitoring of Composite Structures for Re-Usable Space Applications Using FBGs: The Influence of Low Earth Orbit Conditions.

Fiber Bragg grating sensors (FBGs) are promising for structural health monitoring (SHM) of composite structures in space owing to their lightweight nature, resilience to harsh environments, and immunity to electromagnetic interference. In this paper, we investigated the influence of low Earth orbit (LEO) conditions on the integrity of composite structures with embedded optical fiber sensors, specifically FBGs. The LEO conditions were simulated by subjecting carbon fiber-reinforced polymer (CFRP) coupons to 10 cycles of thermal conditioning in a vacuum (TVac). Coupons with embedded optical fibers (OFs) or capillaries were compared with reference coupons without embedded OFs or capillaries. Embedded capillaries were necessary to create in situ temperature sensors. Tensile and compression tests were performed on these coupons, and the interlaminar shear strength was determined to assess the influence of TVac conditioning on the integrity of the composite. Additionally, a visual inspection of the cross-sections was conducted. The impact on the proper functioning of the embedded FBGs was tested by comparing the reflection spectra before and after TVac conditioning and by performing tensile tests in which the strain measured using the embedded FBGs was compared with the output of reference strain sensors applied after TVac conditioning. The measured strain of the embedded FBGs showed excellent agreement with the reference sensors, and the reflection spectra did not exhibit any significant degradation. The results of the mechanical testing and visual inspection revealed no degradation of the structural integrity when comparing TVac-conditioned coupons with non-TVac-conditioned coupons of the same type. Consequently, it was concluded that TVac conditioning does not influence the functionality of the embedded FBGs or the structural integrity of the composite itself. Although in this paper FBG sensors were tested, the results can be extrapolated to other sensing techniques based on optical fibers.

Inferior results at long-term follow-up after extensor mechanism allograft reconstruction in septic compared to aseptic revision total knee arthroplasty.

PURPOSE: Extensor mechanism lesion after total knee arthroplasty (TKA) is a catastrophic complication. Reconstruction with extensor mechanism allograft (EMA) has been described as a sound salvage procedure. Its effectiveness at long term and in septic cases is still under scrutiny. The long-term results of EMA reconstruction for chronic extensor mechanism failures following aseptic and septic revision TKA have been analysed. METHODS: From the institutional database, 35 patients with a revision TKA (RevTKA) undergoing EMA reconstruction from 2005 to 2015 have been retrospectively identified. A history of periprosthetic joint infection (PJI) was found in 13 (37%) patients. The mean follow-up was 81.2 months (± 34.7, range 3-120). EMA failures were considered for lag more than 20°, Knee Society Score (KSS) less than 60 points, and/or in the case of revision of the allograft. RESULTS: The mean KSS improved from 35.9 (± 16.9, range 0-54) to 86.6 (± 10.4, range 54-99) points in the aseptic group (p < 0.001) and from 27.5 (± 11.6, range 10-44) to 79.4 (± 16.3, range 48-94) points in the septic group (p < 0.001). The extensor lag changed from 48.4° (± 14.5, range 30-90) to 4.6° (± 10.8, range 0-50) in the aseptic group (p < 0.001) and from 56.5° (± 20.8, range 30-90) to 6.1° (± 6.8, range 0-20) in the septic group (p < 0.001). The mean postoperative flexion was 105.2° (± 13.2, range 75-130) in the aseptic group and 102.7° (± 12.5, range 80-120) in the septic group (p = 0.32). Three failures (14% of the cases) occurred in the aseptic group and five in the septic group (38% of the cases). The overall survivorship at 10 years was 83.3% (22 cases, CI95 94.2-121.7) vs 58% (13 cases, CI95 67.2-111.7) in the aseptic and septic group, respectively (p = 0.01). CONCLUSIONS: EMA reconstruction after extensor mechanism disruptions in TKA is a reliable salvage procedure. The septic nature of the revision decreased the functionality of the knee joint after EMA, but it did not represent a risk factor for re-ruptures or recurrence of infection. LEVEL OF EVIDENCE: Level III.

New Horizons of Cementless Total Knee Arthroplasty.

BACKGROUND: Considering the increasing number of young and active patients needing TKA, orthopedic surgeons are looking for a long-lasting and physiological bond for the prosthetic implant. Multiple advantages have been associated with cementless fixation including higher preservation of the native bone stock, avoidance of cement debris with subsequent potential third-body wear, and the achievement of a natural bond and osseointegration between the implant and the bone that will provide a durable and stable fixation. DISCUSSION: Innovations in technology and design have helped modern cementless TKA implants to improve dramatically. Better coefficient of friction and reduced Young's modulus mismatch between the implant and host bone have been related to the use of porous metal surfaces. Moreover, biologically active coatings have been used on modern implants such as periapatite and hydroxyapatite. These factors have increased the potential for ingrowth by reducing micromotion and increasing osteoconductive properties. New materials with better biocompatibility, porosity, and roughness have been introduced to increase implant stability. CONCLUSIONS: Innovations in technology and design have helped modern cementless TKA implants improve primary stability in both the femur and tibia. This means that short-term follow-up are comparable to cemented. These positive prognostic factors may lead to a future in which cementless fixation may be considered the gold-standard technique in young and active patients.

Bilateral Extensor Mechanism Allograft Reconstruction for Chronic Spontaneous Rupture: A Case Report and Review of the Literature.

CASE: A 51-year-old woman, affected by end-stage renal disease, presented with 16-month-old ruptures of the right patellar tendon and the left quadriceps tendon. Since she had been nonambulatory for more than a year, the authors decided to perform a bilateral one-staged reconstruction with an Achilles tendon allograft on the right side and a full extensor mechanism allograft on the left side, achieving excellent clinical and functional results at 57 months' follow-up. CONCLUSIONS: Bilateral spontaneous rupture of the extensor mechanism of the knee is a rare but dramatic occurrence. Allograft can be considered as a treatment option in case of chronic lesion or delayed reconstruction, with satisfactory midterm outcomes.

Bragg-Grating-Based Photonic Strain and Temperature Sensor Foils Realized Using Imprinting and Operating at Very Near Infrared Wavelengths.

Thin and flexible sensor foils are very suitable for unobtrusive integration with mechanical structures and allow monitoring for example strain and temperature while minimally interfering with the operation of those structures. Electrical strain gages have long been used for this purpose, but optical strain sensors based on Bragg gratings are gaining importance because of their improved accuracy, insusceptibility to electromagnetic interference, and multiplexing capability, thereby drastically reducing the amount of interconnection cables required. This paper reports on thin polymer sensor foils that can be used as photonic strain gage or temperature sensors, using several Bragg grating sensors multiplexed in a single polymer waveguide. Compared to commercially available optical fibers with Bragg grating sensors, our planar approach allows fabricating multiple, closely spaced sensors in well-defined directions in the same plane realizing photonic strain gage rosettes. While most of the reported Bragg grating sensors operate around a wavelength of 1550 nm, the sensors in the current paper operate around a wavelength of 850 nm, where the material losses are the lowest. This was accomplished by imprinting gratings with pitches 280 nm, 285 nm, and 290 nm at the core-cladding interface of an imprinted single mode waveguide with cross-sectional dimensions 3 × 3 µm². We show that it is possible to realize high-quality imprinted single mode waveguides, with gratings, having only a very thin residual layer which is important to limit bend losses or cross-talk with neighboring waveguides. The strain and temperature sensitivity of the Bragg grating sensors was found to be 0.85 pm/µÎµ and -150 pm/°C, respectively. These values correspond well with those of previously reported sensors based on the same materials but operating around 1550 nm, taking into account that sensitivity scales with the wavelength.

Surgical options for chronic patellar tendon rupture in total knee arthroplasty.

PURPOSE: The purpose of this study was to compare mid-term results of three different reconstructive techniques for chronic patellar tendon disruption after total knee arthroplasty (TKA). Several surgical techniques have been proposed, but to date it is still unclear which is the best solution. The hypothesis was that allografts provide better functional results than autografts in restoring a correct joint function. METHODS: Twenty-one reconstructions were performed in twenty-one patients (three groups of seven patients) with chronic patellar tendon lesion following TKA. Group I underwent reconstruction with an Achilles tendon allograft with a calcaneal block, Group II with an autograft of the quadriceps tendon reinforced by the semitendinosus tendon and Group III with a full extensor mechanism allograft consisting of the tibial tubercle, patellar tendon, patella, and quadriceps tendon. Preoperatively and at each follow-up, the value of the extensor lag and the Knee Score (KS) were recorded. RESULTS: The mean extensor lag decreased from 50° ± 19.4° to 3° ± 1.6°. The KSS improved from 44.7 ± 20.5 to 78.9 ± 13.6 points. The comparison between the groups showed statistically significant differences in the mean postoperative KS between Groups I (average score of 87.7 ± 14.3 points) and II (average score of 70 ± 4.1 points), but not between Groups I and III (average score of 78.9 ± 14.6 points) or between Groups II and III. Differences in the postoperative extensor lag were not significant between the three groups. CONCLUSIONS: The present study may serve surgeons in choosing the best reconstructive strategy for a chronic patellar tendon lesion in TKA. According to the reported results, an Achilles tendon allograft should be considered the gold standard repair. The autograft technique is suitable when the host tissue is competent, particularly when dealing with younger patients or post-infection. A full extensor mechanism allograft may represent a reliable solution when the defect involves the patellar bone or the quadriceps tendon. LEVEL OF EVIDENCE: IV.

High performance of α-defensin lateral flow assay (Synovasure) in the diagnosis of chronic knee prosthetic infections.

PURPOSE: This prospective study was undertaken to evaluate the diagnostic accuracy of the Synovasure™ α-defensin lateral flow assay to detect or exclude infection and to compare it to the sensitivity and specificity of other diagnostic criteria according to the International Consensus Group on Periprosthetic Joint Infection (PJI). METHODS: All patients who have undergone revision total knee arthroplasty (TKA) from September 2015 to July 2016 were included: 16 chronic (more than 3 months after performing arthroplasty) infections and 35 aseptic joints were identified. The diagnostic performance of single test was assessed by receiver operating characteristic (ROC) curve analyses. The sensitivity and specificity were calculated for each of the cut-off values and the area under the curve (AUC) was also calculated. RESULTS: The median synovial fluid (SF) leukocyte count, as well as the neutrophil percentage, was significantly higher in patients with PJI than in those with aseptic failure (p < 0.001). The sensitivity of α-defensin was 87.5% (95%; CI 74.6-94.7), the specificity was 97.1% (95% CI 86.9-99.7), the positive predictive value 93.3% (95% CI 81.8-98.1), and negative predictive value was 94.4% (95% CI 83.2-98.6). The results in terms of sensitivity and negative predictive value were greater than those of the other tests (cultures, synovial cell count, erythrocyte sedimentation rate, and C-reactive protein). The diagnostic accuracy of α-defensin, with an area under the curve of 0.92, was found to be higher than all the minor criteria for PJI. CONCLUSIONS: In this study, the α-defensin lateral flow test was found to have the highest performance of all tests studied to identify PJI. Synovasure™ holds the potential to be included in the daily clinical practice. LEVEL OF EVIDENCE: Level I diagnostic study.

Diagnostic accuracy of synovial fluid, blood markers, and microbiological testing in chronic knee prosthetic infections.

INTRODUCTION: This retrospective study was undertaken to define cut-off values for synovial fluid (SF) leukocyte count and neutrophil percentage for differentiating aseptic failure and periprosthetic joint infection (PJI) and to evaluate the diagnostic accuracy of blood inflammatory markers, and microbiological testing according to the criteria proposed by the International Consensus Meeting (ICM) of Philadelphia. METHODS: All patients who underwent revision total knee arthroplasty from January 2010 to July 2015 were included: we identified and classified 31 PJIs and 136 aseptic joints. The diagnostic performance of single test was assessed by receiver operating characteristic curve analyses. The sensitivity and specificity were calculated for each of the cut-off values and the area under the curve (AUC) was calculated. RESULTS: The median SF leukocyte count as well as the neutrophil percentage and inflammatory markers were significantly higher in patients with PJI than in those with aseptic failure (p < 0.001). A leukocyte count of > 2.8 × 103/µL had a sensitivity of 83.8% and a specificity of 89.7% whereas a neutrophil percentage of > 72% yielded a marginally higher sensitivity of 84% and a specificity of 91%. Applying the ICM criteria we found a significant correlation between all these diagnostic measures and PJI (p < 0.001) except for a single positive culture. The most accurate criterion of the ICM was the synovial neutrophil differential (AUC = 0.89; 95% CI 0.81-0.97), followed by SF leukocyte count (AUC = 0.86; 95% CI 0.78-0.94), increased inflammatory markers (AUC = 0.85; 95% CI 0.76-0.93), and two positive periprosthetic cultures (AUC = 0.84; 95% CI 0.73-0.94). The presence of sinus tract communicating with the joint and a single positive culture showed unfavourable diagnostic accuracy (AUC = 0.60, 95% CI 0.47-0.72; AUC = 0.49, 95% CI 0.38-0.61, respectively) CONCLUSIONS: The present study highlights the adequate ability of fluid cell count and neutrophil differential to distinguish between PJI and aseptic loosening. The clinical utility of fluid analysis in diagnosing infection can be improved by evaluation of other diagnostic criteria. LEVEL OF EVIDENCE: Level I Diagnostic Study.

Detection, Localization and Quantification of Impact Events on a Stiffened Composite Panel with Embedded Fiber Bragg Grating Sensor Networks.

Nowadays, it is possible to manufacture smart composite materials with embedded fiber optic sensors. These sensors can be exploited during the composites' operating life to identify occurring damages such as delaminations. For composite materials adopted in the aviation and wind energy sector, delaminations are most often caused by impacts with external objects. The detection, localization and quantification of such impacts are therefore crucial for the prevention of catastrophic events. In this paper, we demonstrate the feasibility to perform impact identification in smart composite structures with embedded fiber optic sensors. For our analyses, we manufactured a carbon fiber reinforced plate in which we embedded a distributed network of fiber Bragg grating (FBG) sensors. We impacted the plate with a modal hammer and we identified the impacts by processing the FBG data with an improved fast phase correlation (FPC) algorithm in combination with a variable selective least squares (VS-LS) inverse solver approach. A total of 164 impacts distributed on 41 possible impact locations were analyzed. We compared our methodology with the traditional P-Inv based approach. In terms of impact localization, our methodology performed better in 70.7% of the cases. An improvement on the impact time domain reconstruction was achieved in 95 . 1 % of the cases.

RTM Production Monitoring of the A380 Hinge Arm Droop Nose Mechanism: A Multi-Sensor Approach.

This research presents a case study of production monitoring on an aerospace composite component: the hinge arm of the droop nose mechanism on the Airbus A380 wing leading edge. A sensor network composed of Fibre Bragg Gratings, capacitive sensors for cure monitoring and thermocouples was embedded in its fibre reinforced lay-up and measurements were acquired throughout its Resin Transfer Moulding production process. Two main challenges had to be overcome: first, the integration of the sensor lines in the existing Resin Transfer Moulding mould without modifying it; second, the demoulding of the component without damaging the sensor lines. The proposed embedding solution has proved successful. The wavelength shifts of the Fibre Bragg Gratings were observed from the initial production stages, over the resin injection, the complete curing of the resin and the cooling-down prior to demoulding. The sensors proved to be sensitive to detecting the resin flow front, vacuum and pressure increase into the mould and the temperature increase caused by the resin curing. Measurements were also acquired during the post-curing cycle. Residual strains during all steps of the process were derived from the sensors' wavelength shift, showing values up to 0.2% in compression. Moreover, the capacitive sensors were able to follow-up the curing degree during the production process. The sensors proved able to detect the resin flow front, whereas thermocouples could not measure an appreciable increase of temperature due to the fact that the resin had the same temperature as the mould.

Vibration Monitoring Using Fiber Optic Sensors in a Lead-Bismuth Eutectic Cooled Nuclear Fuel Assembly.

Excessive fuel assembly vibrations in nuclear reactor cores should be avoided in order not to compromise the lifetime of the assembly and in order to prevent the occurrence of safety hazards. This issue is particularly relevant to new reactor designs that use liquid metal coolants, such as, for example, a molten lead-bismuth eutectic. The flow of molten heavy metal around and through the fuel assembly may cause the latter to vibrate and hence suffer degradation as a result of, for example, fretting wear or mechanical fatigue. In this paper, we demonstrate the use of optical fiber sensors to measure the fuel assembly vibration in a lead-bismuth eutectic cooled installation which can be used as input to assess vibration-related safety hazards. We show that the vibration characteristics of the fuel pins in the fuel assembly can be experimentally determined with minimal intrusiveness and with high precision owing to the small dimensions and properties of the sensors. In particular, we were able to record local strain level differences of about 0.2 µÏµ allowing us to reliably estimate the vibration amplitudes and modal parameters of the fuel assembly based on optical fiber sensor readings during different stages of the operation of the facility, including the onset of the coolant circulation and steady-state operation.

Dynamic Strain Measurements on Automotive and Aeronautic Composite Components by Means of Embedded Fiber Bragg Grating Sensors.

The measurement of the internal deformations occurring in real-life composite components is a very challenging task, especially for those components that are rather difficult to access. Optical fiber sensors can overcome such a problem, since they can be embedded in the composite materials and serve as in situ sensors. In this article, embedded optical fiber Bragg grating (FBG) sensors are used to analyze the vibration characteristics of two real-life composite components. The first component is a carbon fiber-reinforced polymer automotive control arm; the second is a glass fiber-reinforced polymer aeronautic hinge arm. The modal parameters of both components were estimated by processing the FBG signals with two interrogation techniques: the maximum detection and fast phase correlation algorithms were employed for the demodulation of the FBG signals; the Peak-Picking and PolyMax techniques were instead used for the parameter estimation. To validate the FBG outcomes, reference measurements were performed by means of a laser Doppler vibrometer. Sensors 2015, 15 27175 The analysis of the results showed that the FBG sensing capabilities were enhanced when the recently-introduced fast phase correlation algorithm was combined with the state-of-the-art PolyMax estimator curve fitting method. In this case, the FBGs provided the most accurate results, i.e. it was possible to fully characterize the vibration behavior of both composite components. When using more traditional interrogation algorithms (maximum detection) and modal parameter estimation techniques (Peak-Picking), some of the modes were not successfully identified.

Influence of fiber Bragg grating spectrum degradation on the performance of sensor interrogation algorithms.

The working principle of fiber Bragg grating (FBG) sensors is mostly based on the tracking of the Bragg wavelength shift. To accomplish this task, different algorithms have been proposed, from conventional maximum and centroid detection algorithms to more recently-developed correlation-based techniques. Several studies regarding the performance of these algorithms have been conducted, but they did not take into account spectral distortions, which appear in many practical applications. This paper addresses this issue and analyzes the performance of four different wavelength tracking algorithms (maximum detection, centroid detection, cross-correlation and fast phase-correlation) when applied to distorted FBG spectra used for measuring dynamic loads. Both simulations and experiments are used for the analyses. The dynamic behavior of distorted FBG spectra is simulated using the transfer-matrix approach, and the amount of distortion of the spectra is quantified using dedicated distortion indices. The algorithms are compared in terms of achievable precision and accuracy. To corroborate the simulation results, experiments were conducted using three FBG sensors glued on a steel plate and subjected to a combination of transverse force and vibration loads. The analysis of the results showed that the fast phase-correlation algorithm guarantees the best combination of versatility, precision and accuracy.

Growth factors and stem cells for the management of anterior cruciate ligament tears.

The anterior cruciate ligament (ACL) is fundamental for the knee joint stability. ACL tears are frequent, especially during sport activities, occurring mainly in young and active patients. Nowadays, the gold standard for the management of ACL tears remains the surgical reconstruction with autografts or allografts. New strategies are being developed to resolve the problems of ligament grafting and promote a physiological healing process of ligamentous tissue without requiring surgical reconstruction. Moreover, these strategies can be applicable in association surgical reconstruction and may be useful to promote and accelerate the healing process. The use of growth factors and stem cells seems to offer a new and fascinating solution for the management of ACL tears. The injection of stem cell and/or growth factors in the site of ligamentous injury can potentially enhance the repair process of the physiological tissue. These procedures are still at their infancy, and more in vivo and in vitro studies are required to clarify the molecular pathways and effectiveness of growth factors and stem cells therapy for the management of ACL tears. This review aims to summarize the current knowledge in the field of growth factors and stem cells for the management of ACL tears.

Synthetic augmentation in massive rotator cuff tears.

Massive rotator cuff tears represent a great challenge in orthopaedic. They are associated with persistent defects, weakness, and poor outcomes and can cause an uncoupling of forces across the glenohumeral joint, with unstable shoulder kinematics. In the last few years, a notable interest has emerged to develop new treatment strategies that provide effective mechanical reinforcement of rotator cuff repair and stimulate and enhance the patient's intrinsic healing potential. Tissue engineering techniques using novel scaffold materials offer potential alternatives for managing massive irreparable rotator cuff tears. Synthetic scaffolds, manufactured from chemical compounds, have gained much interest to bridge massive rotator cuff tears. Preliminary studies support the idea that synthetic scaffolds can provide an alternative for rotator cuff augmentation with an enormous therapeutic potential. Despite the growing clinical use of synthetic scaffold devices for rotator cuff repair, there are numerous questions related to their indication, surgical application, safety, mechanism of action, and efficacy that remain to be clarified or addressed. We review the current basic science and clinical understanding of synthetic scaffolds for massive rotator cuff repair, reporting the preclinical and clinical studies carried out to date in this field. We underline the benefits and limitations of the available synthetic scaffolds for augmentation of rotator cuff tears, and discuss the implications of these literature data on the future directions for the use of these scaffolds in tendon repair procedures.

Scaffolds in tendon tissue engineering.

Tissue engineering techniques using novel scaffold materials offer potential alternatives for managing tendon disorders. Tissue engineering strategies to improve tendon repair healing include the use of scaffolds, growth factors, cell seeding, or a combination of these approaches. Scaffolds have been the most common strategy investigated to date. Available scaffolds for tendon repair include both biological scaffolds, obtained from mammalian tissues, and synthetic scaffolds, manufactured from chemical compounds. Preliminary studies support the idea that scaffolds can provide an alternative for tendon augmentation with an enormous therapeutic potential. However, available data are lacking to allow definitive conclusion on the use of scaffolds for tendon augmentation. We review the current basic science and clinical understanding in the field of scaffolds and tissue engineering for tendon repair.

Synthetic augmentation for massive rotator cuff tears.

The management of massive, irreparable rotator cuff tears is challenging. They are associated with persistent defects, weakness, and poor outcomes, and can cause an uncoupling of forces across the glenohumeral joint, with unstable shoulder kinematics. There has been much interest in the development of scaffolds to bridge massive rotator cuff tears. As allograft materials may produce inflammatory responses in the host, there is notable interest in developing synthetic grafts for surgical use. Benefits and limitations of the available synthetic scaffolds for augmentation of rotator cuff tears are reported in the present review.

Tissue engineered biological augmentation for tendon healing: a systematic review.

INTRODUCTION: Tendon injuries give rise to significant morbidity. In the last few decades, several techniques have been increasingly used to optimize tendon healing. SOURCES OF DATA: We performed a comprehensive search of PubMed, Medline, Cochrane, CINAHL and Embase databases using various combinations of the commercial names of each scaffold and the keywords 'tendon', 'rotator cuff', 'supraspinatus tendon', 'Achilles tendon', 'growth factors', 'cytokines', 'gene therapy', 'tissue engineering', 'mesenchymal' and 'stem cells' over the years 1966-2009. All articles relevant to the subject were retrieved, and their bibliographies were hand searched for further references in the context to tissue-engineered biological augmentation for tendon healing. AREAS OF AGREEMENT: Several new techniques are available for tissue-engineered biological augmentation for tendon healing, growth factors, gene therapy and mesenchimal stem cells. AREAS OF CONTROVERSY: Data are lacking to allow definitive conclusions on the use of these techniques for routine management of tendon ailments. GROWING POINTS: The emerging field of tissue engineering holds the promise to use new techniques for tendon augmentation and repair. Preliminary studies support the idea that these techniques can provide an alternative for tendon augmentation with great therapeutic potential. AREAS TIMELY FOR DEVELOPING RESEARCH: The optimization strategies discussed in this article are currently at an early stage of development. Although these emerging technologies may develop into substantial clinical treatment options, their full impact needs to be critically evaluated in a scientific fashion.

Tendon augmentation grafts: a systematic review.

INTRODUCTION: Several biomaterials are available to bridge large tendon defects or reinforce tenuous tendon repairs. METHODS: We performed a comprehensive search of PubMed, Medline, Cochrane, CINAHL, and Embase databases using various combinations of the commercial names of each scaffold and the keywords 'tendon', 'rotator cuff', 'supraspinatus tendon', 'Achilles tendon', 'scaffold', 'biomaterials', 'extracellular matrix', 'substitute', and 'devices' over the years 1966-2009. All articles relevant to the subject were retrieved, and their bibliographies hand searched for further references in the context to biomaterials for tendon repair. RESULTS: Many biomaterials are available for tendon augmentation. Scanty evidence is available for the use of these scaffolds. DISCUSSION: The emerging field of tissue engineering holds the promise to use biomaterials for tendon augmentation. Preliminary studies support the idea that these biomaterials have the ability to provide an alternative for tendon augmentation. However, available data are lacking to allow definitive conclusion on the use of biomaterials for tendon augmentation. Additionally, the prevalence of postoperative complications encountered with their use varies within the different studies. CONCLUSION: Rather than providing strong evidence for or against the use of these materials for tendon augmentation, this study instead generates potential areas for additional prospective investigation.