Anterior cruciate ligament reconstruction : a look at prosthetics - past , present and possible future Biological tissue autograft reconstruction using the patellar tendon or quadrupled semitendinosus/gracilis tendons has become the most popular procedure in surgical treatment of a ruptured ACL . This article provides a review of the history of the use of prosthetics with respect to ACL reconstruction grafts including Carbon Fibre , Gore-Tex and Dacron prosthetics as well as the Leeds-Keio Artificial Ligament and the Kennedy Ligament Augmentation Device -LRB- LAD -RRB- . Emphasis is placed on the Ligament Advanced Reinforcement System -LRB- LARS -RRB- as preliminary investigations of its use have been encouraging . Significant progress has been made recently with respect to the understanding of ACL anatomy , composition , biomechanics , and healing processes , leading to innovative techniques using approaches based in tissue engineering principles and computer -- assisted surgery . While research into improved ACL treatment options continues , the synthesis of recent advancements provides a new optimism towards the regeneration of an ACL mirroring its original stability , function , and longevity . INTRODUCTION The anterior cruciate ligament -LRB- ACL -RRB- is the most frequently injured ligament in the knee and consequently , the majority of research into knee ligament injuries has been directed towards the ACL . While the collateral knee ligaments exhibit strong healing potential and generally respond well to conservative treatment , the anterior cruciate ligament has a poor intrinsic healing ability due to the fact that it is enveloped by synovial fluid and lacks significant vascularization -LRB- 1 -RRB- . Surgical reconstruction is therefore the most frequent mode of treatment pursued when the ACL is torn . The patients who experience ACL injuries are significantly younger and more active than those who experience many other orthopaedic injuries . The need for reconstruction options that exhibit longevity in the face of great stresses is therefore imperative -LRB- 2 -RRB- . Historically , options for surgical treatment have included primary repair with or without synthetic augmentation and reconstruction using either biological tissue grafts or prosthetic ligaments . Primary repairs with or without augmentation have tended to fail at restoring stability to the knee and are not a common treatment option today -LRB- 3 -RRB- . Likewise , prosthetic replacements have traditionally tended to be inadequate due to post-surgical complications arising from wear and degeneration . Hence , biological tissue autograft reconstruction using the patellar tendon or quadrupled semitendinosus/gracilis tendons has become the most popular procedure in surgical treatment of an ACL rupture . However , the frequency of significant anterior knee pain post-surgically and high occurrence of flexion contracture and crepitation in tendon autografts have kept research interests focused on the further development of prosthetic ligament implants . A significant number of early research endeavours into prosthetic ACL replacements failed due to a poor understanding of the biomechanical and physiological properties of the ACL . Tremendous gains in understanding have been made in these areas , with significant progress being made in understanding the inter-dependence between ACL anatomy , tissue composition , biomechanics , and the healing processes . Unfortunately , to date , no prosthesis has proven itself as a viable alternative to the patellar or hamstring tendon autografts , currently used in over 90 % of ACL reconstructions . This article reviews some of the major historical milestones in ACL reconstruction technology and looks forward to the continuing evolution of this technology . The literature used for this review was obtained using the PubMED database with keywords `` anterior cruciate ligament '' searched in tandem separately with `` prosthetics '' and `` tissue engineering . '' It should be noted that many of the studies cited in this review obtained funding from orthopaedic and biomaterial companies that sponsored the implant . SURGICAL REPAIR : ADVANTAGES AND DISADVANTAGES OF BIOLOGICAL TISSUE GRAFTS Bone-patellar tendon-bone -LRB- BPTB -RRB- and semitendinosus/gracilis tendon autografts are currently the most common grafts used in ACL reconstruction . While the BPTB autografts were the former `` gold standard '' , recent studies have identified the quadruple semitendinosus graft as a comparable option for ACL reconstruction -LRB- 4 -RRB- . Advances in hamstring graft fixation have led to similar strengths of fixation between BPTB and semitendinosus/gracilis grafts -LRB- 5 -RRB- . Both techniques now offer a high degree of strength and stiffness in the reconstructed ligament . Additionally , use of the patient 's own tissue eliminates the risk of rejection and good to excellent results are reported in 85 -- 90 % of patients receiving either of these grafts for ACL reconstructions . Nonetheless , with patellar tendon autografts , many patients experience impaired function and significant morbidity at the donor site including secondary anterior knee pain , patellar tendonitis , infrapatellar contracture , and patellar fracture . Likewise , hamstring weakness and saphenous nerve injury can be seen secondary to hamstring harvest in semitendinosus/gracilis autograft ACL reconstruction -LRB- 6 -RRB- . To avoid complications resulting from donor site morbidity in autograft reconstructions , allograft reconstruction has also been examined . While eliminating the donor site morbidity , the use of allografts is not currently considered advantageous due to a limited donor tissue supply , delayed biological incorporation , risks of disease transmission and tissue rejection . In an attempt to overcome these concerns , research into the use of synthetic prosthetic ligaments began over 30 years ago and continues today in hopes of eliminating donor site morbidity and reducing the risk of disease transmission and supply shortages . One of the main obstacles in finding an adequate prosthetic replacement for the ACL is the longevity of the graft , with autogenous tissue consistently proving to be a more durable and long-lasting replacement than the many biomaterials that have been applied to ACL replacement -LRB- 7 -RRB- . PROSTHETIC BEGINNINGS AND PAST USE The first attempts at a synthetic ACL reconstruction were conducted by Alwyn-Smith in 1918 using silk sutures ; they however failed within 3 months -LRB- 8 -RRB- . Reconstruction with a prosthetic ligament made of polytetrafluoroethylene -LRB- PTFE -RRB- with embedded carbon or aluminum oxide fibers -LRB- Proplast -RRB- was first reported in 1973 -LRB- 9 -RRB- . Results with this system yielded an average time to breakage of just over 1 year . A report by James et al. suggests that only 52 % of reconstructions utilizing this graft yielded satisfactory results -LRB- 10 -RRB- . Satisfactory results include all grafts that patients were content with and had not ruptured at time of lastest follow-up . Current classification systems for synthetic replacements of the ACL include grafts , ligament augmentation devices , or total prosthetics . Grafts -LRB- polyethylene , PTFE -RRB- , typically fixed at both ends , were the initial focus of synthetic ACL replacement and were meant to provide stability to the ACL-deficient-knee until secondary reconstruction procedures gained popularity -LRB- 11 -RRB- . Similarly , ligament augmentation devices -LRB- polypropylene , polyester -RRB- were intended to provide immediate protection for autogenous tissue grafts until revascularization was complete and the ingrown tissue was capable of withstanding local tensile and compressive forces . Unfortunately , these devices may in fact accomplish the opposite of their intended purpose by stress-shielding autogenous tissue , preventing it from developing adequate mechanical strength . Fixed at both ends like a graft , the total prosthesis was intended as a permanent ACL replacement without any soft-tissue ingrowth that would allow the patient to begin aggressive rehabilitation immediately as no tissue maturation or revascularization was required . While the implantation of a full-strength ACL replacement generally led to excellent short-term results , long-term efficacy results were poor due to wear and ensuing rupture of the prosthesis -LRB- 11 -RRB- . Combining the mechanical focus provided by these prior prosthetic approaches with tissue engineering principles has led to the development of a scaffold design intended to serve as a foundation for soft tissue in-growth . Scaffolds may be permanent or may be 31 Vol . 11 No. 1 Anterior Cruciate Ligament Reconstruction : A Look at Prosthetics intended to gradually degenerate as the host tissue replaces them . Problems associated with the biological incorporation of scaffolds include variability of tissue in-growth , immature degeneration of the implant and insufficient maturation of the host tissue resulting in an inability of the scaffold to withstand inherent mechanical stresses placed on the ACL . Current directions in this area involve the use of tissue engineering focusing on developing a mechanically and biologically functional matrix for the scaffold and the use of in vitro mechanical signals to guide new tissue development -LRB- 11 -RRB- . Table 1 summarizes the advantages of the various prosthetic ACL graft options that have been attempted and are discussed below . CARBON FIBRE PROSTHETICS Some of the earliest attempts to discover an appropriate alternative to the biological graft resulted in a variety of carbon fibre prostheses that varied greatly with respect to material and implantation technique . In 1977 , Jenkins et al. were the first to use a flexible carbon fibre implant , and suggested that the carbon fibre induced the formation of tendon in animals and humans -LRB- 12 -RRB- . However , subsequent studies reported the generation and migration of carbon wear particles into the joint space and regional lymph nodes following implantation of the prosthesis -LRB- 12 -RRB- . To combat this problem , attempts were made to coat the carbon fibre with collagen and absorbable polymers . Of particular interest was a carbon fibre implant proposed by Alexander et al. coated with a co-polymer of polylactic acid -LRB- PLA -RRB- and polycapralactone -LRB- 13 -RRB- . The carbon filaments were thought to act as a scaffold for tissue ingrowth by evenly distributing and reducing the interfacial stress between the implant and soft tissue attachment , while the PLA/polycapralactone would protect the fibre during implantation . Over time , the PLA was meant to resorb and the carbon fibres degrade as new tissue developed , thereby encouraging normal tissue regeneration without permanently replacing it -LRB- 13 -RRB- . A 24-month study involving 82 patients was conducted by Weiss et al. to further examine the PLA coated prosthesis using a variety of subjective and objective measures -LRB- pain , stability , function , and isokinetic strength testing -RRB- , which revealed significant improvements over the duration of the study -LRB- 14 -RRB- . Arthroscopic evaluation demonstrated collagenous tissue ingrowth , confirmed by histological studies , to be composed of Type I and III collagen in similar proportions to that found in normal healing ligamentous tissue -LRB- 14 -RRB- . A similar design was used in the Surgicraft ABC prosthetic ACL -LRB- Surgicraft Ltd. , Redditch UK -RRB- composed of carbon and polyester fibres oriented in a partial braid by a zig-zag pattern . However , a study by O'Brien et al. with an average follow-up of 34 months showed only 11 of 31 knees -LRB- 41 % -RRB- had good results defined as a Lysholm score greater than 76 . The Lysholm knee score is an outcome measure that assesses knee function on a 100 point scale . The authors also noted unacceptable stretching and complete rupture as major complications and concluded that the implant is unsuitable for clinical use -LRB- 15 -RRB- . GORE-TEX PERMANENT PROSTHESIS The Gore-Tex ligament prosthesis is composed of a single long fiber of expanded polytetrafluoroethylene -LRB- PTFE -RRB- arranged into loops . Extensive mechanical testing has shown that the resulting ultimate tensile strength is about 3 times that of the human ACL and the results from cyclical creep tests and bending fatigue testing seem to identify Gore-Tex as the strongest synthetic ACL replacement in terms of pure material stability -LRB- 16 -RRB- . Bolton and Bruchman reported that 129 out of 130 patients receiving a high strength PTFE ligament showed improved knee stability at 15 months or less -LRB- 16 -RRB- . Glousman et al. reported an initial improvement upon physical examination and subjective scores . However , at mean follow-up of 18 months , they reported a progressive loosening of the prosthesis -LRB- 17 -RRB- . Similarly , Woods et al. presented 2 - and 3-year follow-up of Gore-Tex ACL reconstructions and showed a similar pattern of early improvement post-operatively , but deterioration over time . They reported an overall failure rate of 33 % at 3-year follow-up -LRB- 18 -RRB- . Indelicato et al. 's follow-up of Gore-Tex implant ACL reconstructions showed a 90 % success rate at 2 years versus only a 76 % success rate at 3 years or more -LRB- 19 -RRB- . Despite similar reports describing complications with the Gore-Tex ACL prosthesis , subjective results in several studies remain acceptable at 60 -- 80 % -LRB- 17 , 19 -RRB- . The Gore-Tex ACL prosthesis is currently FDA approved for use in patients who have had a failed autogenous intra-articular graft procedure . DACRON With its success as a vascular surgery implant -LRB- 20 -RRB- , various forms of Dacron grafts have been developed as a scaffold for ACL replacements . The implant is a composite of four tightly woven polyester strips wrapped in a sheath of loosely woven velour , designed to minimize abrasion of the graft and act as a scaffold for fibrous tissue ingrowth . A report by Lukianov et al. reviewed the short-term follow-up -LRB- mean 28 months -RRB- of 41 patients who underwent ACL reconstruction with the Stryker Dacron ligament prosthesis -LRB- 3 -RRB- . Seventy-five percent of the patients were found to have a negative Lachman , anterior drawer , and pivot shift at their most recent follow-up . However , Richmond et al. reported failure rates of 37.1 % in a study of Dacron reconstruction with mean long-term follow-up of 50 months -LRB- 21 -RRB- . Likewise , Barrett et al. reported higher failure rates of 47.5 % after a four-year follow-up period -LRB- 22 -RRB- . A clinical study by Lopez-Vazquez et al. examining ACL reconstruction with a Dacron prosthesis showed a similar deterioration of results after the first post-operative year -LRB- 23 -RRB- . With the initial short-term strength shown by these grafts offset by their poor long-term stability , Dacron grafts should not be considered a viable alternative for ACL reconstruction . LEEDS-KEIO ARTIFICIAL LIGAMENT With the desire to design a graft that combined the properties of a permanent prosthesis and a tissue-promoting scaffold , Fujikawa and Seedhom developed the Leeds-Keio artificial ligament : a polyester mesh-like structure anchored to the femur and tibia with bone plugs -LRB- 24 -RRB- . This mesh was intended as a scaffold for soft tissue ingrowth through the intra-articular and extra-articular sections of the ligament , eventually uniting the bone plugs . The implant was considered sufficiently flexible to be effective with a maximal tensile strength of approximately 2100 Newtons -LRB- N -RRB- , which significantly exceeds that of the average young adults ' natural ACL -LRB- about 1730 N -RRB- -LRB- 24 -RRB- . Initial descriptions from the inventors also described minimal articular wear with the ligament -LRB- 24 -RRB- . The inventors of this graft have reported successful clinical results with arthroscopic observations documenting neoligamentous tissue within the implanted Dacron scaffold . Other investigators , however , have reported the ingrowth of non-aligned fibrous tissue -LRB- i.e. non-neoligamentous tissue -RRB- within the device after implantation and suggested that the Leeds-Keio ligament did not serve as a true scaffolding graft , but instead behaved as a permanent load-bearing prosthesis , subject to long-term failure in the joint -LRB- 25 -RRB- . McLoughlin and Smith presented a 3.8 year follow-up study of 25 patients implanted with the Leeds-Keio ligament for chronic ACL instability . They reported a low complication rate and considerable success in the elimination of instability after finding good post-operative results with the anterior drawer test using an arthrometer at 90 ° of flexion -LRB- 26 -RRB- . Nevertheless , ensuing long-term follow-up studies showed a deterioration of results after the first post-operative year and a large number of long-term graft ruptures despite excellent early results in stability testing and on the Lysholm scale -LRB- 27 -RRB- . These findings were similar to earlier results reported by Schindhelm , who found that good early results in a sheep model were not maintained -LRB- 28 -RRB- . Due to the number of long-term graft ruptures and the lack of long-term stability provided , the Leeds-Keio ligament is no longer suitable for reconstruction of the human ACL -LRB- 27 , 28 -RRB- . KENNEDY LIGAMENT AUGMENTATION DEVICE -LRB- LAD -RRB- Kennedy et al. introduced the concept of the Ligament Augmentation Device -LRB- LAD -RRB- in 1980 -LRB- 29 -RRB- . The graft , composed of a band-like braid of polypropylene , was originally developed to reinforce the area of pre-patellar tissue considered to be a weak area of autogenous patellar tendon grafts . Use of this prosthesis employed the MacIntosh/Marshall transfer of a portion of the rectus femoris tendon , pre-patellar tissue , and central third of the patellar tendon in an over-the-top fashion -LRB- 30 -RRB- . Originally , the graft was developed to protect the autogenous tissue graft from excessive stresses during the initial remodelling phase -LRB- characterized by degeneration and revascularization -RRB- , allowing for earlier resumption of pre-operative activity levels -LRB- 29 -RRB- . Research has shown that the percentage of load accepted by the LAD varies according to the type of graft employed and method of reconstruction . Comparisons of the patellar tendon and semitendinosus/gracilis LAD composite grafts revealed that the LAD will accept approximately 28 % and 45 % of the applied load , respectively -LRB- 31 -RRB- . To prevent excessive stress shielding that would otherwise prevent the autogenous tissue from developing a normal functional tensile strength , the LAD was attached to the bone at only one end . Despite a promising beginning , the suture interface between the LAD and the graft was identified as the weak link of the composite . Whether collagen fibres become truly incorporated into the LAD remains a controversial issue . Most histological evidence has been derived from animal studies and thus may not be fully indicative of results in humans . Nevertheless , this evidence seems to point to adequate longitudinal collagenization of the graft with inconclusive results on whether or not collagen ingrowth within the LAD has occurred -LRB- 32 -RRB- . Furthermore , as an intra-articular foreign body , the LAD has been reported to induce an inflammatory response characterized by foreign body giant cells and macrophages in the surrounding tissue . A review by Kumar et al. reported that the majority of complications seen following use of the LAD were characterized as effusions and reactive synovitis , likely a result of LAD-induced inflammatory response -LRB- 23 -RRB- . The decline in use of the aforementioned MacIntosh/Marshall transfer , combined with the weak graft-prosthetic suture interface and propensity of the LAD to cause high rates of post-operative synovitis have resulted in a lack of widespread use of the device . THE FUTURE : LIGAMENT ADVANCED REINFORCEMENT SYSTEM -LRB- LARS -RRB- ARTIFICIAL LIGAMENT The Ligament Advanced Reinforcement System -LRB- LARS -RRB- -LRB- Arc-sur-Tille , France -RRB- artificial ligament consists of fibres made of polyethylene terephthalate -LRB- PET -RRB- . An intra-osseous segment is composed of longitudinal fibres bound together by a transverse knitted structure while an intra-articular segment is composed of parallel longitudinal fibres twisted at 90 ° . The main innovation of this artificial ligament lies in its ability to mimic the natural ligamentous structure and reduce shearing forces by orientating the free fibers of the intra-articular portion of the graft clockwise or counter-clockwise for use in right and left knees , respectively . Furthermore , the PET fibres of the intra-articular segment are designed to encourage tissue ingrowth due to the porosity of the material , allowing ingrowth from the surrounding osseous tunnels . Ideally , such tissue ingrowth between the ligament fibres would contribute to the viscoelasticity of the graft and protect against friction at the opening of the bony canal and between the fibres themselves -LRB- 1 -RRB- . A study by Lavoie et al. examined ACL reconstruction with the use of the LARS artificial ligament . Thirty-eight of forty-seven patients suffered from chronic ruptures of the ACL , while nine others presented with acute or subacute ruptures at a mean follow-up of 21.9 months . Six patients had previously had an unsuccessful ACL reconstruction . The Knee Osteoarthritis Outcome Score -LRB- KOOS -RRB- was administered to assess patients ' opinions regarding their knee , while a modified International Knee Documentation Committee -LRB- IKDC -RRB- scoring system was used to examine knee stability . The IKDC form initially consisted of seven knee-related parameters that were each rated as either normal , nearly normal , abnormal , and severely abnormal . The worst score amongst the seven categories determined the final score . The form was later modified in 2001 to include subjective factors such as symptoms , sports activities , and ability to function . The Tegner activity scale , a subjective ten point activity scale , was obtained to assess patient activity levels . A Telos radiographic stress system was used to examine anterior knee displacement , which involves obtaining radiographs with the knee in ninety degrees of flexion and a posterior force applied to the knee . When results are compared to the normal knee , this test helps in the assessment of post-operative laxity in the reconstructed knee which may indicate that the graft is failing . None of the patients presented symptoms of synovitis , but longer follow-up time is required to properly draw conclusions with respect to patient outcome . Although Tegner scores improved significantly following surgery , no patients returned to pre-injury activity levels . Data obtained by the KOOS demonstrated patient satisfaction ranged from 73.5 to 93.0 % . In comparison to the uninjured knee , post-operative Telos stress radiography and the Lachman test indicated an average posterior-anterior displacement of 7.3 mm for the involved knee -LRB- 28 -RRB- . A more complete examination of the LARS artificial ligament was provided in a subsequent study by the same authors . Nau et al. conducted a two-year follow-up randomized controlled trial that compared the BPTB autograft with the LARS artificial ligament method of ACL reconstruction in 53 patients with chronic instability -LRB- 1 -RRB- . Like the preceding study , assessments included clinical examination , anterior laxity testing , as well as the KOOS , IKDC , and Tegner scores . In particular , IKDC evaluation revealed little significant difference between the two methods . Follow-up values for instrumented laxity testing were greater in the LARS group . While similar overall results were obtained for both groups , these results may suggest that a full return to activity may be hastened by using the LARS artificial ligament rather than the conventional BPTB technique -LRB- 1 -RRB- . Another recent study by Talbot et al. examined the use of the LARS artificial ligament for ligament reconstruction in knee dislocations -LRB- 2 -RRB- . Twenty patients were included with a mean follow-up of 27.4 months . Each patient was evaluated using the Lysholm score , underwent clinical examination to identify ligamentous laxity and range of motion , and completed the ACL quality of life -LRB- ACL-QoL -RRB- questionnaire . The mean Lysholm score was 71.7 , which is lower than scores reported by several other studies -LRB- range of 74.7 to 91.3 -RRB- investigating the outcomes of knee dislocations treated with surgery as reported by Fanelli -LRB- 35 -RRB- . Following the same trend , Telos radiometry revealed a mean residual laxity of 5 mm in patients post-surgery , which is also greater than these previously reported results . The average range of motion post-surgery was 118 ° with a mean fixed flexion contracture of 2 ° -LRB- 2 -RRB- . Although preliminary investigations into the use of the LARS artificial ligament have been encouraging , concerns regarding the risk of rupture remain and must be addressed through long-term follow-up studies . TISSUE ENGINEERING ADVANCES Permanent synthetic prostheses are capable of duplicating the mechanical and structural properties of the ACL . However , they generally tend to lose strength with time . Tissue-based or tissue-aided implants offer the additional possibility of the restoration of normal joint kinematics while the mechanical behaviour of these implants is expected to improve over time as tissues are remodelled within the knee -LRB- 36 -RRB- . An ideal ACL scaffold must meet the immediate functional mechanical demands within the reconstructed knee , however , they must also degrade at a rate similar to that of tissue ingrowth . Accordingly , the ACL scaffold should lose its mechanical integrity while allowing the remodelled tissues to gain strength and accept an increasing amount of the mechanical demands placed on the ACL . Current research into this novel tissue-engineering approach has focused on seeding either collagen-based scaffolds or synthetic biodegradable polymers with a variety of different cell types . In hopes of stimulating early healing , reducing biomaterial-related inflammatory response and improving neoligament formation , several researchers have sought to adopt a cell sheeting technique to improve the performance of the synthetic ACL scaffold . Several groups have conducted experiments on this tissue-engineered approach to ACL ligament reconstruction using both fibroblast-seeded synthetic scaffolds and collagen-based prosthetics -LRB- 37 , 38 -RRB- . Bellincampi et al. measured the ingrowth characteristics of rabbit fibroblasts on skin and ACL scaffolds -LRB- 39 -RRB- . Subsequent in vivo studies suggested that fibroblast-seeded collagen scaffolds were viable after re-implantation into the donor rabbit . The major limitations of these approaches are the allogenicity of the collagen scaffolds , often leading to further complications . Collagen-based constructs also suffer from batch-to-batch variability , making consistent reproduction of these prostheses difficult . Collagen does not offer the same flexibility for modification that is reported with the technology of biodegradable polymers -LRB- 6 -RRB- . As an alternative to the scaffolds made of non-degradable polymers , investigators have begun to examine biodegradable materials that would provide immediate stabilization to the repaired ligament but would also act as a scaffold for the ingrowth and/or replacement by host cells . Cao et al. described the generation of neo-tendons in a nude mice model by implanting polyglycolic acid -LRB- PGA -RRB- scaffolds seeded with bovine tendon fibroblasts in the subcutaneous space of athymic mice -LRB- 40 -RRB- . Using a similar system , Koski et al. reported the formation of ligament-like structures when fibroblasts isolated from bovine cruciate ligaments were seeded onto PGA scaffolds and implanted subcutaneously in nude mice -LRB- 6 -RRB- . In both studies , the tissue developed histological characteristics similar to normal tendon and ligament over time . Ouyang et al. reported that bone marrow stromal cells -LRB- bMSCs -RRB- seeded onto poly-lactic and - glycolic acid -LRB- PLGA -RRB- scaffolds grew as a multi-layer of cells intertwined in a collagen matrix synthesized by the cells 35 Vol . 11 No. 1 Anterior Cruciate Ligament Reconstruction : A Look at Prosthetics themselves . They also noted that the cell sheet formed faster than scaffolds seeded with terminally differentiated cells , such as fibroblasts and smooth muscle cells -LRB- 41 -RRB- . They reported that degradation of the scaffolds occurred over time , as indicated by a decrease in failure load . Altman et al. seeded 6-cord silk scaffolds with human bone marrow stromal cells and cultured them for 14 -- 21 days . Their results similarly suggested a slow degradation of the scaffolds . However , fatigue analysis and subsequent regression analysis revealed an expected matrix lifetime equivalent to 1 year in vivo . While these reports are an estimate , the authors suggest that this is a marked improvement compared to similar studies using collagen scaffolds -LRB- 36 -RRB- . The future of tissue engineering may also require a significant contribution from cell-specific growth factors influencing the maturation and homeostasis of the healing response of ligament tissue . Studies have suggested that individual growth factors may have an important effect on cell division and enhance ligament healing , while others have pointed to the synergistic effect of a combination of growth factors as important to cell outgrowth in ACL explants -LRB- 42 , 43 -RRB- . In a study observing the effects of several growth factors on the cell migration , proliferation and collagen production in human ACL cells , Murray et al. suggested that specific dose-response relationships may exist for the optimal activity of each growth factor -LRB- 44 -RRB- . These authors observed that the addition of transforming growth factor -LRB- TGF -RRB- β-1 led to an increased cell population , as well as increased collagen and smooth muscle actin production in human ACL cells cultured on top of a collagen-glycosaminoglycan scaffold . Despite the complex nature of the inter-dependent factors at play during the recovery and rehabilitative period following an ACL reconstruction , much of the literature today suggests that tissue engineering techniques will lead to a new generation of ACL replacements , capable of regenerating a mechanically robust and natural ACL . COMPUTER-ASSISTED ACL RECONSTRUCTION In an attempt to improve the accuracy and reproducibility of ACL graft placement , several groups have turned to computer-assisted surgery in an attempt to reduce the incidence of graft failure -LRB- 45 , 46 -RRB- . These systems are capable of modeling the placement and predicting the impingement of an ACL graft based on intra-operative anatomical landmarks and signals received at an opto-electric camera . These studies reported that experience level did not affect the placement of the tunnels . Computer-assisted ACL replacement reduces variance in tunnel placement and allows residents and less experienced surgeons to limit complications and control tunnel positioning -LRB- 46 -RRB- . Based on the success of navigation systems for total knee and hip replacements , the use of computer-assisted ACL reconstruction may lead to similarly dramatic improvements in technical and functional outcomes . CONCLUSION Satisfactory prosthetic replacement of the ACL has been a focus of orthopaedic research endeavours for the past thirty years . Desires to provide immediate mobility and strength to the ACL-deficient knee while avoiding the donor site morbidity caused by the commonly used autograft surgical techniques continually drive new research initiatives . Most of the grafts that have been developed to date have failed due to unsatisfactory long-term physiologic and functional performance . Most permanent ACL prostheses are prone to creep , fatigue , and mechanical failure within several years after implantation -LRB- 40 -RRB- . Tissue ingrowth scaffolds and ligament augmentation devices require further refinement to provide effective mechanical support while avoiding stress-shielding of the host tissue . In view of these factors , prosthetics are not widely used today in ACL reconstruction , and autogenous tissue grafts remain the gold standard used by the majority of surgeons . Perhaps development of resorbable , tissue-inducing and cell-seeded biomaterials will improve the long-term biomechanical performance of the reconstructed anterior cruciate ligament . Advances in tissue engineering combined with developments in molecular biology and gene therapy may couple with the rapid gains in computer-assisted surgery to provide improved options for the ACL-deficient knee , with a greater potential to restore its pre-injury state .

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O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O B I I O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

anterior cruciate ligament
biomaterials
prosthetics
tissue engineering


Prevalence

of

Risk

Factors

for

Adverse

Pregnancy

Outcomes

During

Pregnancy

and

the

Preconception

Period

United

States

Objectives

To

assess

the

prevalence

of

risk

factors

for

adverse

pregnancy

outcome

during

the

preconception

stage

and

during

pregnancy

and

to

assess

differences

between

women

in

preconception

and

pregnancy

Methods

Data

from

the

and

Behavioral

Risk

Factor

Surveillance

System

United

States

were

used

to

estimate

the

prevalence

of

selected

risk

factors

among

women

in

the

preconception

period

-LRB-

women

who

wanted

a

baby

in

the

next

months

and

were

not

using

contraception

not

sterile

and

not

already

pregnant

-RRB-

with

women

who

reported

that

they

were

pregnant

at

the

time

of

interview

Results

Major

health

risks

were

reported

by

substantial

proportions

of

women

in

the

preconceptional

period

and

were

also

reported

by

many

pregnant

women

although

pregnant

women

tended

to

report

lower

levels

of

risk

than

preconception

women

For

example

of

preconception

women

reported

one

or

more

of

risk

factors

-LRB-

frequent

drinking

current

smoking

and

absence

of

an

HIV

test

-RRB-

compared

with

of

pregnant

women

-LRB-

p

-RRB-

The

difference

in

the

prevalence

of

these

three

risk

factors

between

preconception

and

pregnancy

was

significant

for

women

with

health

insurance

-LRB-

in

preconception

vs.

in

pregnancy

p

-RRB-

but

not

for

women

without

insurance

-LRB-

vs.

p

-RRB-

Conclusions

Women

appear

to

be

responding

to

messages

regarding

behaviors

that

directly

affect

pregnancy

such

as

smoking

alcohol

consumption

and

taking

folic

acid

but

many

remain

unaware

of

the

benefits

of

available

interventions

to

prevent

HIV

transmission

and

birth

defects

Although

it

appears

that

some

women

reduce

their

risk

for

adverse

pregnancy

outcomes

after

learning

of

their

pregnancy

the

data

suggest

that

a

substantial

proportion

of

women

do

not

Furthermore

if

such

change

occurs

it

is

often

too

late

to

affect

outcomes

such

as

birth

defects

resulting

from

alcohol

consumption

during

the

periconception

period

Preconception

interventions

are

recommended

to

achieve

a

more

significant

reduction

in

risk

and

further

improvement

in

perinatal

outcomes

Introduction

Although

the

US

has

achieved

substantial

gains

in

improving

the

health

of

women

and

children

and

infant

mortality

has

reached

record

low

levels

the

US

presently

ranks

among

established

market

economies

in

infant

mortality

-LSB-

-RSB-

Four

recurring

causes

account

for

more

than

half

of

all

infant

deaths

birth

defects

disorders

related

to

short

gestation

and

preterm

birth

maternal

complications

of

pregnancy

-LRB-

including

complications

of

the

placenta

cord

and

membranes

-RRB-

and

sudden

infant

death

syndrome

-LSB-

-RSB-

In

recent

years

some

causes

of

infant

mortality

have

increased

particularly

in

the

percentage

of

births

that

were

preterm

and

of

low

birth

weight

-LSB-

-RSB-

In

congenital

anomalies

low

birth

weight

preterm

delivery

and

maternal

complications

of

pregnancy

accounted

for

-LRB-

-RRB-

of

the

infant

deaths

-LSB-

-RSB-

Relatively

little

is

known

about

the

risk

factors

underlying

the

continued

increase

in

these

adverse

outcomes

Adequate

prenatal

care

has

long

been

considered

as

an

opportunity

to

reduce

such

risks

However

despite

increases

in

access

to

and

utilization

of

early

prenatal

care

interventions

and

efforts

directed

at

addressing

such

risk

factors

fall

short

of

their

goal

Indeed

the

effects

of

such

efforts

may

have

reached

their

peak

and

new

approaches

may

be

necessary

Reviews

on

selected

risk

factors

indicate

that

a

large

proportion

of

women

enter

pregnancy

with

pre-existing

risks

for

adverse

pregnancy

outcomes

Although

some

women

tend

to

take

action

to

reduce

their

risk

as

soon

as

they

learn

that

they

are

pregnant

the

extent

of

pregnancy

related

change

in

risk

factors

varies

considerably

and

often

does

not

occur

early

in

pregnancy

when

teratogenic

effects

are

more

pronounced

Moreover

post-pregnancy

relapse

is

high

-LSB-

-RSB-

For

example

in

the

period

the

reported

reduction

in

the

use

of

alcohol

tobacco

and

illicit

drugs

in

the

first

trimester

was

and

respectively

-LSB-

-RSB-

Such

information

is

important

to

the

emerging

emphasis

on

preconception

care

as

a

complementary

approach

to

reduce

risks

to

pregnancy

This

paper

provides

nationally-representative

estimates

on

risks

during

the

preconception

period

and

describes

the

apparent

reductions

in

risk

achieved

during

pregnancy

for

all

known

risk

factors

for

which

data

are

available

Data

The

estimates

presented

herein

are

based

on

data

from

the

Behavioral

Risk

Factor

Surveillance

System

-LRB-

BRFSS

-RRB-

-LSB-

-RSB-

However

because

not

all

risk

indicators

that

were

considered

were

included

in

the

BRFSS

data

were

used

for

a

small

number

of

risk

indicators

for

which

the

BRFSS

provided

the

most

recently

available

data

The

BRFSS

is

an

ongoing

annual

telephone

survey

of

the

non-institutionalized

adult

civilian

population

aged

years

and

older

conducted

in

each

state

The

survey

obtains

information

on

a

wide

range

of

modifiable

risk

behaviors

In

the

median

response

rate

for

the

BRFSS

state

surveys

was

percent

This

rate

represents

an

estimate

of

the

percentage

of

eligible

respondents

that

completed

telephone

interviews

and

is

computed

based

on

procedures

recommended

by

the

Council

of

American

Survey

Research

Organizations

-LRB-

-RRB-

In

comparison

with

other

national

surveys

BRFSS

data

appear

to

be

of

good

quality

-LSB-

-RSB-

Additional

technical

information

is

available

online

at

The

survey

includes

core

modules

asked

in

all

states

rotating

modules

asked

every

second

year

in

all

states

and

optional

modules

that

are

included

only

in

some

states

Being

a

general

survey

the

BRFSS

lacks

information

on

some

factors

of

interest

to

the

present

topic

for

example

month

of

pregnancy

for

pregnant

women

or

information

on

prenatal

care

Further

the

BRFSS

is

not

designed

specifically

to

study

all

known

risk

behaviors

at

preconception

or

pregnancy

In

addition

as

an

interview

survey

the

survey

relies

on

self-reported

data

which

contain

an

unknown

level

of

reporting

error

Identification

of

women

in

the

preconception

group

in

the

BRFSS

is

made

possible

by

questions

introduced

in

the

family

planning

section

of

the

questionnaire

The

availability

of

these

questions

makes

it

possible

to

compare

risk

behaviors

among

women

about

to

become

pregnant

with

those

who

are

already

pregnant

on

a

large

and

nationally-representative

sample

of

women

Women

in

the

preconception

period

were

identified

as

those

who

reported

that

they

wanted

a

baby

in

the

next

months

were

not

using

contraception

were

not

sterile

and

were

not

already

pregnant

Women

who

were

pregnant

were

identified

based

on

the

response

to

the

question

To

your

knowledge

are

you

now

pregnant

Age

of

gestation

was

not

assessed

in

this

survey

Data

were

aggregated

across

states

to

make

national

estimates

For

this

resulted

in

a

total

national

U.S.

sample

of

women

aged

to

years

of

whom

-LRB-

-RRB-

were

classified

into

the

preconception

period

and

-LRB-

-RRB-

reported

that

they

were

pregnant

at

the

time

of

their

interview

The

corresponding

number

of

women

in

the

are

women

with

-LRB-

-RRB-

in

the

preconception

period

and

-LRB-

-RRB-

pregnant

women

The

analysis

on

folic

acid

and

vitamins

are

based

on

surveys

in

states

in

The

results

for

these

items

are

generalizable

to

the

populations

of

these

states

-LRB-

shown

in

Table

-RRB-

but

not

to

the

entire

United

States

population

Table

of

age

and

race/ethnicity

Women

in

preconception

and

pregnant

-LRB-

BRFSS

-RRB-

and

Births

-LRB-

Vital

Statistics

data

-RRB-

BRFSSPreconception

womenPregnant

womenVital

statisticsPercentCIPercentCIbirths

PercentAge

group

Race/ethnicity

NH

NH

Note

For

BRFSS

estimates

confidence

interval

Percent

CI

Vital

statistics

data

Hamilton

BE

Martin

JA

Ventura

SJ

Sutton

PD

Menacker

F.

Births

Preliminary

data

for

National

vital

statistics

reports

vol

no

Hyattsville

Maryland

National

Center

for

Health

Statistics

Table

risk

indicators

by

pregnancy

status

Women

and

BRFSSPreconception

womenPregnant

data

nationwidea

General

Health

Poor/fair

general

health

days

in

past

month

mental

health

not

good

No

health

plan

No

dental

visit

past

Told

had

diabetes

HIV

Do

n't

know

about

prevention

of

MTC

HIV

Never

tested

for

HIV

or

more

HIV

risk

category

Alcohol/smoking

Any

alcohol

in

past

month

Average

or

more

drink

per

day

past

month

Binging

Any

occasions

of

drinks

in

past

month

Frequent

drinking

binging

or

or

more

drinks

per

day

Current

smoker

Obesity

Overweight

body

mass

index

-LRB-

BMI

-RRB-

Obese

BMI

data

states

onlyb

c

Folic

acid

Do

n't

know

about

folic

acid

for

birth

defects

Do

n't

take

vitamins

of

any

kind

Do

n't

take

folic

acid

or

multivitamin

Do

n't

take

folic

acid

or

multivitamin

daily

Nutrition

-LRB-

BRFSS

-RRB-

d

Fewer

than

servings/fruit

and

vegetables

Fewer

than

servings/fruit

and

Note

confidence

interval

Percent

CI.aUnweighted

number

of

observations

Preconception

women

-LRB-

-RRB-

Pregnant

Women

-LRB-

-RRB-

bUnweighted

number

of

observations

Preconception

women

-LRB-

-RRB-

Pregnant

Women

-LRB-

-RRB-

cStates

AZ

CO

FL

KY

MN

MT

NC

ND

NE

TX

VA

WI.dUnweighted

number

of

observations

Preconception

women

-LRB-

-RRB-

Pregnant

Women

-LRB-

-RRB-

p

preconception

vs.

pregnant

women

HIV

risk

Any

statement

is

true

in

past

year

illegal

drug

injection

treated

for

STD

exchange

for

money/drugs

uprotected

anal

intercourse

Statistical

methods

The

percentage

of

women

exposed

to

risk

indicators

was

identified

for

women

in

groups

women

in

the

preconception

period

and

pregnant

women

-LRB-

Table

-RRB-

The

categories

of

risk

indicators

for

which

data

are

available

include

perceived

general

and

mental

health

lack

of

medical

insurance

knowledge

of

HIV

prevention

and

practices

alcohol

and

tobacco

use

obesity

nutrition

including

folic

acid

uptake

for

the

prevention

of

birth

defects

and

presence

of

chronic

medical

conditions

Because

these

are

not

longitudinal

data

it

was

not

possible

to

observe

behavior

change

in

individual

women

Rather

the

prevalence

of

risk

factors

was

compared

between

preconception

and

pregnant

women

as

a

proxy

measure

of

pregnancy-related

risk

reduction

-LSB-

-RSB-

although

is

is

possible

that

other

factors

could

influence

the

differences

between

preconception

and

pregnant

women

The

statistical

significance

between

preconception

and

pregnant

women

of

the

percentage

reporting

each

risk

factor

was

assessed

using

a

t-test

All

statistical

analysis

was

based

on

weighting

factors

designed

to

produce

unbiased

estimates

and

statistical

tests

were

adjusted

for

complex

sample

design

using

the

software

for

survey

data

analysis

-LRB-

SUDAAN

Research

Triangle

Institute

Research

Triangle

Park

NC

-RRB-

Results

Comparisons

with

vital

statistics

data

on

births

in

indicate

that

the

BRFSS

respondents

in

the

preconception

stage

and

pregnant

when

interviewed

were

distributed

very

similarly

by

age

and

race-ethnicity

to

women

giving

birth

in

-LRB-

Table

-RRB-

Overall

for

many

risk

factors

pregnant

women

reported

lower

prevalence

of

risk

than

preconception

women

-LRB-

Table

-RRB-

Percentages

reporting

alcohol

consumption

and

smoking

were

much

lower

for

pregnant

women

than

preconception

women

For

example

of

preconception

women

reported

any

use

of

alcohol

in

the

past

month

compared

with

of

pregnant

women

of

preconception

women

reported

current

smoking

in

contrast

to

of

pregnant

women

and

in

the

states

that

included

the

question

of

preconception

women

reported

not

taking

vitamins

with

folic

acid

versus

of

pregnant

women

For

some

risk

indicators

no

statistically

significant

difference

was

observed

between

women

in

the

preconception

period

and

pregnant

women

The

lack

of

awareness

about

methods

to

prevent

mother-to-child

HIV

transmission

-LRB-

PMTCT

-RRB-

was

not

significantly

different

between

preconception

women

and

pregnant

women

-LRB-

vs.

-RRB-

However

a

small

but

significantly

higher

percentage

of

pregnant

women

reported

HIV

risk

-LRB-

-RRB-

compared

to

preconception

women

-LRB-

-RRB-

which

is

perhaps

related

to

sexual

risk

behaviors

being

causally

linked

to

both

HIV

and

to

unplanned

pregnancies

Of

concern

is

that

although

a

lower

percentage

of

pregnant

women

compared

with

preconception

women

had

never

been

tested

for

HIV

about

one-fourth

of

pregnant

women

remained

untested

despite

national

recommendations

that

call

for

all

pregnant

women

to

be

tested

for

HIV

-LSB-

-RSB-

In

the

case

of

chronic

diseases

such

as

diabetes

the

lower

level

of

disease

among

pregnant

women

may

indicate

self-selection

of

diabetic

women

to

avoid

pregnancy

Of

note

nearly

one

fifth

of

the

women

in

preconception

period

were

obese

-LRB-

defined

as

having

a

body

mass

index

or

BMI

of

greater

than

-RRB-

and

twice

that

number

were

overweight

-LRB-

BMI

of

greater

than

-RRB-

-LRB-

Table

-RRB-

Most

preconception

and

pregnant

women

did

not

report

consuming

the

recommended

servings

of

fruits

and

vegetables

per

day

-LSB-

-RSB-

although

the

percentage

was

lower

for

pregnant

women

-LRB-

-RRB-

compared

with

women

in

the

preconception

period

-LRB-

-RRB-

Indicators

of

general

well

being

and

recent

dental

care

were

not

different

between

women

in

preconception

period

and

pregnancy

A

composite

measure

of

basic

pregnancy

risks

was

formed

frequent

alcohol

consumption

current

smoking

and

lack

of

an

HIV

test

in

order

to

use

the

BRFSS

data

to

illustrate

the

size

of

the

target

populations

for

preconception

care

These

are

risk

factors

for

which

we

have

data

that

are

generalizable

to

the

US

population

and

for

which

interventions

or

information

are

widely

available

or

promoted

The

results

indicate

that

of

preconception

women

reported

one

or

more

of

these

risk

factors

which

represents

approximately

million

preconception

women

-LRB-

Table

-RRB-

percent

of

pregnant

women

had

one

or

more

of

these

risks

which

is

equivalent

to

pregnant

women

Table

also

shows

this

composite

risk

factor

by

measures

of

access

to

health

care

whether

the

woman

had

a

health

plan

or

insurance

and

whether

she

had

a

personal

physician

Pregnant

women

had

a

lower

percent

at

risk

in

all

categories

except

for

those

without

health

insurance

Among

women

without

insurance

the

percentage

reporting

risk

was

not

significantly

lower

for

pregnant

women

compared

with

preconception

women

This

suggests

that

women

with

poorer

access

to

health

care

as

indicated

by

no

health

insurance

are

not

as

likely

as

others

to

adopt

healthier

behaviors

when

they

become

pregnant

Table

and

estimated

number

reporting

any

of

risks

for

pregnancy

outcomea

for

preconception

and

pregnant

women

aged

Women

BRFSSPreconception

women

-LRB-

Estimated

number

-RRB-

Currently

pregnant

women

-LRB-

Estimated

number

-RRB-

No

health

No

personal

Note

confidence

interval

Percent

CI

and

Estimated

number

CI

Estimated

number

is

the

estimated

number

of

women

in

the

category

with

one

of

the

risk

factors.aAny

of

risk

factors

frequent

drinking

current

smoker

no

HIV

test

difference

between

preconception

and

pregnant

women

significant

p

Discussion

The

BRFSS

provides

an

opportunity

to

measure

the

extent

of

risk

behaviors

on

a

relatively

large

sample

of

women

who

are

planning

to

become

pregnant

These

nationally-representative

survey

data

indicate

that

major

health

risks

were

reported

by

substantial

proportions

of

US

women

in

the

preconception

period

The

data

suggest

that

among

those

at

risk

during

preconception

the

majority

continued

the

risk

into

pregnancy

Women

appear

to

respond

to

messages

regarding

behaviors

that

can

improve

pregnancy

outcomes

such

as

consuming

of

folic

acid

and

the

reduction

in

smoking

alcohol

consumption

but

many

remain

unaware

of

the

benefits

of

available

interventions

to

prevent

HIV

transmission

and

birth

defects

The

fact

that

more

than

one-third

of

preconception

and

pregnant

women

were

not

aware

of

methods

to

prevent

mother-to-child

HIV

transmission

and

did

not

know

about

the

benefits

of

taking

folic

acid

during

pregnancy

suggests

that

education

and

public

information

programs

could

have

some

effect

in

reducing

risk

behaviors

Risk

reduction

appears

to

be

lower

among

women

who

have

no

health

insurance

Other

data

are

not

available

for

comparison

of

the

overall

burden

of

risk

for

adverse

pregnancy

outcomes

among

women

in

the

preconception

period

or

pregnancy

However

data

on

selected

indicators

presented

here

for

pregnant

women

are

comparable

to

the

reported

range

from

other

studies

-LSB-

-RSB-

The

finding

that

the

percentage

who

report

some

risk

behaviors

is

significantly

lower

among

pregnant

women

compared

with

women

in

the

preconception

period

may

indicate

the

desire

of

many

pregnant

women

to

adopt

healthier

behaviors

to

achieve

the

best

possible

outcome

for

their

pregnancy

Examination

of

three

well

known

risk

factors

for

which

interventions

are

available

-LRB-

frequent

alcohol

consumption

current

smoking

or

never

having

been

tested

for

HIV

-RRB-

illustrates

that

risks

for

adverse

pregnancy

outcomes

exist

among

more

than

half

of

women

in

the

preconception

period

and

among

one-third

of

pregnant

women

Nationwide

this

represents

approximately

one

million

women

in

the

preconception

period

and

pregnant

women

The

data

from

the

BRFSS

are

subject

to

potential

errors

associated

with

survey

research

such

as

exclusion

from

the

sampling

frame

non-response

and

reporting

errors

BRFSS

is

a

telephone-based

survey

and

might

not

be

representative

of

the

small

percentage

of

the

population

without

telephones

The

BRFSS

methodology

contains

steps

to

ensure

accurate

estimation

including

the

use

of

weighting

factors

to

compensate

for

non-response

rates

In

addition

estimates

from

BRFSS

data

have

been

found

to

be

consistent

with

data

from

other

surveys

-LSB-

-RSB-

The

preconception

and

pregnant

women

identified

were

distributed

very

similarly

to

women

giving

birth

in

by

age

group

and

race/ethnicity

providing

support

for

the

representativeness

of

the

data

In

this

report

the

reported

risk

behavior

of

women

in

the

preconception

stage

and

pregnant

women

have

been

compared

as

a

proxy

for

the

type

of

behavior

change

occurring

between

preconception

and

pregnancy

but

other

factors

could

affect

the

actual

change

in

behavior

among

individual

women

For

known

risk

factors

progress

in

efforts

to

reduce

such

risks

among

pregnant

women

has

been

slow

For

example

as

indicated

in

data

collected

on

earlier

rounds

of

the

BRFSS

alcohol

consumption

among

pregnant

women

has

remained

relatively

steady

over

the

past

decade

-LSB-

-RSB-

Even

among

those

who

reduce

consumption

of

alcohol

tobacco

or

drugs

post

pregnancy

relapse

of

such

behaviors

have

been

found

to

be

very

high

-LSB-

-RSB-

Of

the

maternal

and

infant

health

objectives

included

in

the

Healthy

people

objectives

progress

has

been

made

toward

the

target

in

objectives

-LSB-

-RSB-

Little

positive

progress

has

occurred

in

the

areas

of

maternal

death

fetal

alcohol

syndrome

and

low

birth

weight

To

close

the

gap

in

reduction

of

poor

maternal

and

child

health

outcomes

current

maternal

and

child

health

initiatives

should

be

complemented

with

alternate

approaches

including

more

emphasis

on

preconception

health

promotion

strategies

among

women

of

childbearing

age

Recent

experience

in

the

prevention

of

alcohol-exposed

pregnancy

and

prevention

of

neural

tube

defects

through

folic

acid

supplementation

has

shown

that

such

efforts

are

useful

In

the

Project

CHOICES

Research

Group

reported

the

findings

of

a

feasibility

study

designed

to

provide

prevention

counseling

to

women

at

high

risk

for

an

alcohol

exposed

pregnancy

-LSB-

-RSB-

Brief

interventions

were

found

to

be

effective

in

reducing

hazardous

alcohol

use

in

adults

in

a

number

of

well-controlled

studies

Interventions

generally

consist

of

advice

feedback

goal

setting

and

follow-up

for

further

assistance

and

support

-LSB-

-RSB-

The

use

of

a

counseling

style

referred

to

as

motivational

interviewing

has

also

proven

to

be

effective

in

reducing

problem

drinking

-LSB-

-RSB-

Results

of

the

initial

follow-up

assessment

suggest

that

this

approach

can

be

effective

among

women

of

childbearing

age

-LSB-

-RSB-

and

a

larger

efficacy

trial

is

now

underway

To

summarize

our

results

were

consistent

with

a

high

prevalence

of

risk

factors

in

the

preconception

period

and

a

high

degree

continuation

of

risk

into

pregnancy

This

underscores

the

need

for

new

approaches

to

complement

current

prevention

efforts

Given

that

women

of

childbearing

age

in

the

United

States

have

on

an

average

visits

to

physicians

each

year

-LSB-

-RSB-

it

may

be

feasible

to

inform

them

and

engage

them

for

interventions

Such

contacts

may

provide

an

opportunity

to

assess

and

advise

on

many

elements

of

health

mentioned

here

Our

finding

of

high

risk

levels

among

women

who

had

no

insurance

or

no

personal

doctor

strongly

suggests

that

ensuring

access

to

such

services

will

remain

the

key

determinant

of

maximum

uptake

of

known

intervention

services

Medicaid

and

other

funding

programs

can

play

an

important

role

to

address

the

access

gap

whether

during

before

or

after

pregnancy

Attempts

to

improve

the

health

of

would-be

mothers

not

only

improve

pregnancy

and

infant

health

but

also

help

reduce

the

long-term

impact

of

many

risk

factors

on

the

women

themselves

O O O O O O B O O B O O B O O O O O O O O O O O O O O O O O O O B O O O B O O O B O O O O O O O O B O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O B O O O O O O O O O O O B O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O B O O O O O O O O O O B O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O B O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O B O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O B O O B O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O B O O O O O O O B O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O B O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O B O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O B O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O