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Laxity
Kinds of Laxity Selected AbstractsNoninvasive Lower Eyelid Blepharoplasty: A New Technique Using Nonablative Radiofrequency on Periorbital SkinDERMATOLOGIC SURGERY, Issue 2 2004Javier Ruiz-esparza MDArticle first published online: 3 FEB 200 Background. Laxity and rhytids of the lower eyelids are common cosmetic concerns. Historically, correction has either been surgical through either transcutaneous or transconjunctival blepharoplasty or ablative through laser resurfacing or chemical peeling. Therapeutic options usually require significant postoperative healing and have the potential risk of scarring ectropion or pigmentary loss. Objective. To report the use of a new technique that uses nonablative radiofrequency (NARF) to tighten noninvasively and nonsurgically the flaccid skin of the lower eyelids by treating the periorbital area to produce cosmetic improvement. Methods. Nine patients with skin flaccidity of the lower eyelids had a single treatment session with NARF in a small area of skin in the periorbital region, specifically the zygomatic and/or temporal areas. All patients were treated with topical anesthesia only. The treatment lasted approximately 10 minutes. No postoperative care was required. Results. All of the nine patients in the study achieved cosmetic improvement of the eyelids ostensibly through skin contraction. All patients were able to return to their normal routines immediately. Although the results were gradual, patient satisfaction was remarkable. No complications were seen in this study. Conclusion. This new procedure using NARF was successful in providing a safe, noninvasive, cosmetic improvement in these patients with excessive skin laxity of the lower eyelids. Postoperative morbidity, including down time and complications, was not seen. [source] A comparison of cyclic variations in anterior knee laxity, genu recurvatum, and general joint laxity across the menstrual cycleJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 11 2010Sandra J. Shultz Abstract Changes in anterior knee laxity (AKL), genu recurvatum (GR) and general joint laxity (GJL) were quantified across days of the early follicular and early luteal phases of the menstrual cycle in 66 females, and the similarity in their pattern of cyclic variations examined. Laxity was measured on each of the first 6 days of menses (M1,M6) and the first 8 days following ovulation (L1,L8) over two cycles. The largest mean differences were observed between L5 and L8 for AKL (0.32,mm), and between L5 and M1 for GR (0.56°) and GJL (0.26) (p,<,0.013). At the individual level, mean absolute cyclic changes in AKL (1.8,±,0.7,mm, 1.6,±,0.7,mm), GR (2.8,±,1.0°, 2.4,±,1.0°), and GJL (1.1,±,1.1, 0.7,±,1.0) were more apparent, with minimum, maximum and delta values being quite consistent from month to month (ICC2,3,=,0.51,0.98). Although the average daily pattern of change in laxity was quite similar between variables (Spearman correlation range 0.61 and 0.90), correlations between laxity measures at the individual level were much lower (range ,0.07 to 0.43). Substantial, similar, and reproducible cyclic changes in AKL, GR, and GJL were observed across the menstrual cycle, with the magnitude and pattern of cyclic changes varying considerably among females. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:1411,1417, 2010 [source] Improvement in arm and post-partum abdominal and flank subcutaneous fat deposits and skin laxity using a bipolar radiofrequency, infrared, vacuum and mechanical massage deviceLASERS IN SURGERY AND MEDICINE, Issue 10 2009Lori Brightman MD Abstract Background and Objectives Skin laxity of the body is a growing cosmetic concern. Laxity can result from chronological or photoaging and changes in body dimensions during pregnancy or weight loss. The end result is loose, sagging skin, and localized fat deposits. Liposuction and abdominoplasty or brachioplasty are established approaches to these issues. Patient desire for alternatives to surgical correction has spawned the development of non-invasive body contouring devices. The combination of infrared light (IR), bipolar radiofrequency (RF), vacuum and mechanical massage (Velashape, Syneron Medical Ltd, Israel) has demonstrated efficacy in improving skin appearance and circumference of the thighs [Goldberg et al., Derm Surg 2008; 34:204,209; Fisher et al., Derm Surg 2005; 31:1237,1241; Arnoczky and Aksan, J Am Acad Orthop Surg 2000; 8:305,313; Alster and Tanzi, J Cosmetic Laser Therapy 2005; 7:81,85; Wanitphakdeedecha and Manuskiatti, J Cosmet Dermatol 2006; 5:284,288; Nootheti et al., Lasers Surg Med 2006; 38: 908,912], but only anecdotal evidence has supported its use on other anatomic locations. This study was designed to evaluate the efficacy and safety of Velashape on additional body sites and more rigorously examine the technology's impact on upper arm as well as abdominal and flank circumference. Study Design and Methods Subjects were 28,70 years old, skin types I,V. Nineteen subjects underwent 5 weekly treatments of the upper arms, and 10 subjects underwent 4 weekly treatments of the abdomen and flanks. Treatments were performed using Velashape. Circumference measurements, photographs, and subject weights were performed prior to treatment and at 1- and 3-month follow-ups. Subjects were asked to record their treatment satisfaction level. Results Change in arm circumference, at the 5th treatment was statistically significant with a mean loss of 0.625,cm. At 1- and 3-month follow-ups, mean loss was 0.71 and 0.597,cm respectively. Reduction of abdominal circumference at 3rd treatment was statistically significant with a 1.25,cm mean loss. At 1- and 3-month follow-ups, average loss was 1.43 and 1.82,cm respectively. Conclusions This study demonstrates with statistical significance, sustainable reduction in circumference and improvement in appearance of arms and abdomen following treatment with Velashape. Lasers Surg. Med. 41:791,798, 2009. © 2009 Wiley-Liss, Inc. [source] Relationship of meniscal damage, meniscal extrusion, malalignment, and joint laxity to subsequent cartilage loss in osteoarthritic kneesARTHRITIS & RHEUMATISM, Issue 6 2008Leena Sharma Objective Progressive knee osteoarthritis (OA) is believed to result from local factors acting in a systemic environment. Previous studies have not examined these factors concomitantly or compared quantitative and qualitative cartilage loss outcomes. The aim of this study was to test whether meniscal damage, meniscal extrusion, malalignment, and laxity each predicted tibiofemoral cartilage loss after controlling for the other factors. Methods Laxity and alignment were measured at baseline in individuals with knee OA. Magnetic resonance imaging included spin-echo coronal and sagittal imaging for meniscal scoring and axial and coronal spoiled gradient echo sequences with water excitation for cartilage quantification. Tibial and weight-bearing femoral condylar subchondral bone area and cartilage surface were segmented. Cartilage volume, denuded bone area, and cartilage thickness were quantified in each plate, with progression defined as cartilage loss >2 times the coefficient of variation for each plate. Qualitative outcome was assessed as worsening of the cartilage score. Logistic regression analysis with generalized estimating equations yielded odds ratios for each factor, adjusting for age, sex, body mass index, and the other factors. Results We studied 251 knees in 153 persons. After full adjustment, medial meniscal damage predicted medial tibial cartilage volume loss and tibial and femoral denuded bone increase, while varus malalignment predicted medial tibial cartilage volume and thickness loss and tibial and femoral denuded bone increase. Lateral meniscal damage predicted every lateral outcome. Laxity and meniscal extrusion had inconsistent effects. After full adjustment, no factor except medial laxity predicted qualitative outcome. Conclusion Using quantitative cartilage loss assessment, local factors that independently predicted tibial and femoral loss included medial meniscal damage and varus malalignment (medially) and lateral meniscal damage (laterally). A measurement of quantitative outcome was more sensitive at revealing these relationships than a qualitative approach. [source] Measurement of varus,valgus and internal,external rotational knee laxities in vivo,Part II: relationship with anterior,posterior and general joint laxity in males and femalesJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 8 2007Sandra J. Shultz Abstract We examined sex differences in general joint laxity (GJL), and anterior,posterior displacement (ANT,POST), varus,valgus rotation (VR,VL), and internal,external rotation (INT,EXT) knee laxities, and determined whether greater ANT and GJL predicted greater VR,VL and INT,EXT. Twenty subjects were measured for GJL, and scored on a scale of 0,9. ANT and POST were measured using a standard knee arthrometer at 133 N. VR,VL and INT,EXT were measured using a custom joint laxity testing device, defined as the angular displacements (deg) of the tibia relative to the femur produced by 0,10 Nm of varus,valgus torques, and 0,5 Nm of internal,external torques, respectively. INT,EXT were measured during both non-weight-bearing (NWB) and weight-bearing (WB,=,40% body weight) conditions while VR,VL were measured NWB. All laxity measures were greater for females compared to males except for POST. ANT and GJL positively predicted 62.5% of the variance in VR,VL and 41.8% of the variance in WB INT,EXT. ANT was the sole predictor of INT,EXT in NWB, explaining 42.3% of the variance. These findings suggest that subjects who score higher on clinical measures of GJL and ANT are also likely to have greater VR,VL and INT,EXT knee laxities. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:989,996, 2007 [source] Biomechanical effects of medial,lateral tibial tunnel placement in posterior cruciate ligament reconstructionJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 1 2003Keith L. Markolf With most posterior cruciate (PCL) reconstruction techniques, the distal end of the graft is fixed within a tibial bone tunnel. Although a surgical goal is to locate this tunnel at the center of the PCL's tibial footprint, errors in medial,lateral tunnel placement of the tibial drill guide are possible because the position of the tip of the guide relative to the PCL's tibial footprint can be difficult to visualize from the standard arthroscopy portals. This study was designed to measure changes in knee laxity and graft forces resulting from mal-position of the tibial tunnel medial and lateral to the center of the PCL's tibial insertion. Bone,patellar tendon,bone allografts were inserted into three separate tibial tunnels drilled into each of 10 fresh-frozen knee specimens. Drilling the tibial tunnel 5 mm medial or lateral to the center of the PCL's tibial footprint had no significant effect on knee laxities: the graft pretension necessary to restore normal laxity at 90° of knee flexion (laxity match pretension) with the medial tunnel was 13.8 N (29%) greater than with the central tunnel. During passive knee flexion,extension, graft forces with the medial tibial tunnel were significantly higher than those with the central tunnel for flexion angles greater than 65° while graft forces with the central tibial tunnel were not significantly different than those with the lateral tibial tunnel. Graft forces with medial and lateral tunnels were not significantly different from those with a central tunnel for 100 N applied posterior tibial force, 5 N m applied varus and valgus moment, and 5 N m applied internal and external tibial torque. With the exception of slightly higher graft forces recorded with the medial tunnel beyond 65° of passive knee flexion, errors in medial,lateral placement of the tibial tunnel would not appear to have important effects on the biomechanical characteristics of the reconstructed knee. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] Medial collateral ligament autografts have increased creep response for at least two years and early immobilization makes this worseJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 2 2002G. M. Thornton Recent evidence has shown that 10,40% of knee joints reconstructed with soft-tissue autografts have a recurrence of abnormal joint laxity over time. One possible explanation is the "stretching out" (or unrecovered creep) of the graft tissue. To test in vitro creep and creep recovery of fresh anatomic ligament autografts in an extra-articular environment, 16 rabbits underwent an orthotopic medial collateral ligament (MCL) autograft procedure to one hindlimb. Three subgroups of animals had either unrestricted cage activity for 1 year (n = 5) or 2 years (n = 5) or pin-immobilization for the first 6 weeks followed by cage activity for the remainder of 1 year (n = 6). Following laxity measurements, to test their creep response, isolated MCL grafts were cyclically and then statically creep tested in vitro at 4.1 MPa, allowed to recover at zero load for 20 min, and finally elongated to failure. Due to differences in cross-sectional area between the grafts and normal MCLs, two normal control groups were tested: stress-matched tested at 4.1 MPa (16.2 N; n = 7) and force-matched tested at 29.1 N (7.1 MPa; n = 6). Ligament grafts had normal laxity but significantly increased creep and decreased creep recovery compared to normal MCLs after 1 and 2 years of healing (p < 0.0004). Graft failure stress was also significantly less than normal (p < 0.0001). Immobilized grafts had significantly greater creep compared to non-immobilized grafts at 1 year of healing (p < 0.05). These results support previous observations concerning material inferiority of fresh anatomic rabbit MCL autografts, but add the concept that such grafts also have increased potential to creep with either slower or incomplete recovery when subjected to low stresses in vitro. Joint and ligament laxities in situ were normal in this model, however, suggesting either that in vivo MCL graft stresses are lower than those used here in vitro or that these tissues have other mechanisms by which they can recover their functional length in vivo. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] Review of Fractional Photothermolysis: Treatment Indications and EfficacyDERMATOLOGIC SURGERY, Issue 10 2009EMILY P. TIERNEY MD BACKGROUND Fractional photothermolysis (FP) is one of the most significant milestones in laser technology and resurfacing. METHODS Review of the Medline English literature and recent international conferences regarding FP technology, applications, and indications. RESULTS Successful conditions treated with nonablative FP reported in the literature include acne scarring; dyschromia and fine wrinkling of photoaging on the face, chest, neck, and hands; melasma; poikiloderma of Civatte; nevus of Ota; scars; minocycline hyperpigmentation; telangiectatic matting; residual hemangioma; granuloma annulare; colloid milium; and disseminated superficial actinic porokeratosis. An advance in 2007 was the introduction of ablative FP (AFP), which results in significantly greater improvement in skin laxity and textural abnormalities. Most recently, AFP has demonstrated significantly greater improvement than nonablative FP in reducing acne scarring and skin redundancy and laxity associated with photoaging. CONCLUSIONS Through the induction of microthermal zones of injury, FP technology stimulates a robust and rapid wound healing response resulting in improvement in a diversity of aesthetic, inflammatory, and preneoplastic skin disorders. Further investigation into the technology and diverse array of cutaneous conditions that can benefit from FP is highly needed. [source] Differential Long-Term Stimulation of Type I versus Type III Collagen After Infrared IrradiationDERMATOLOGIC SURGERY, Issue 7 2009YOHEI TANAKA MD BACKGROUND The dermis is composed primarily of type I (soft) and type III (rigid scar-like) collagen. Collagen degradation is considered the primary cause of skin aging. Studies have proved the efficacy of infrared irradiation on collagen stimulation but have not investigated the differential long-term effects of infrared irradiation on type I and type III collagen. OBJECTIVE To determine differential long-term stimulation of type I and type III collagen after infrared (1,100,1,800 nm) irradiation. METHODS AND MATERIALS In vivo rat tissue was irradiated using the infrared device. Histology samples were analyzed for type I and III collagen stimulation, visual changes from baseline, and treatment safety up to 90 days post-treatment. RESULTS Infrared irradiation provided long-term stimulation of type I collagen and temporary stimulation of type III collagen. Treatment also created long-term smoothing of the epidermis, with no observed complications. CONCLUSIONS Infrared irradiation provides safe, consistent, long-term stimulation of type I collagen but only short-term stimulation in the more rigid type III collagen. This is preferential for cosmetic patients looking for improvement in laxity and wrinkles while seeking smoother, more youthful skin. [source] Near Painless, Nonablative, Immediate Skin Contraction Induced by Low-Fluence Irradiation with New Infrared Device: A Report of 25 PatientsDERMATOLOGIC SURGERY, Issue 5 2006JAVIER RUIZ-ESPARZA MD BACKGROUND Nonablative radiofrequency (NARF) has been the only method for producing noninvasive skin tightening. Nevertheless, significant pain during the procedure is an important downside of this technology. A new nonablative medical device, Titan (Cutera, Inc., Brisbane, CA, USA), capable of fluences much lower than those possible with NARF, was tested as a less painful alternative. OBJECTIVES To produce skin contraction leading to lifting of eyebrows and/or improvement of lower face and neck skin laxity using fluences below pain levels. PATIENTS AND METHODS Twenty-five patients were treated. Standardized photographs were obtained preoperatively, after a few days, a few weeks, and up to 12 months after the procedure. RESULTS Immediate changes were obtained in 22 of 25 patients. Examination of photographs revealed that the initial improvement was maintained throughout the follow-up period. CONCLUSION Immediate true skin contraction persisting through the immediate, intermediate, and long-term follow-up was found in the vast majority of patients in this group. Edema as an artifact simulating immediate improvement was excluded by serial photographs taken during the follow-up period. Skin contraction occurred at low fluences, below the threshold of pain. This, to the best of our knowledge, has not been previously described in the medical literature. [source] Combination Surgical Lifting with Ablative Laser Skin Resurfacing of Facial Skin: A Retrospective AnalysisDERMATOLOGIC SURGERY, Issue 9 2004Tina S. Alster MD Background. Cutaneous aging is manifested by rhytides, dyschromias, and skin laxity. Ablative laser skin resurfacing can effectively improve many signs of skin aging; however, the photoaged patient with facial laxity often requires a surgical lifting procedure in order to obtain optimal results. Concerns with delayed or impaired wound healing has led to reluctance to perform both procedures simultaneously. Objective. To report the clinical results and side effect profiles after concomitant surgical facial lifting procedures and ablative carbon dioxide or erbium:YAG laser resurfacing in a series of patients. Methods. A retrospective analysis and chart review was performed in 34 consecutive patients who underwent combination CO2 or erbium:YAG laser skin resurfacing and surgical lifting procedures, including S-lift rhytidectomy, blepharoplasty, and brow lift. Side effects and complication rates were tabulated. Results. The side effect profile of the combined surgical-laser procedures was similar to that reported after a laser-only procedure. The most common side effect was transient hyperpigmentation which occurred in 20.6% of treated patients. None of the patients experienced delayed reepithelialization, skin necrosis, or prolonged healing times. Conclusions. Concurrent laser skin resurfacing and surgical lifting of facial skin maximizes aesthetic results without increased incidence of adverse effects. Patients benefit from the consolidation of anesthesia and convalescent times as well as enhanced global clinical outcomes. [source] Noninvasive Lower Eyelid Blepharoplasty: A New Technique Using Nonablative Radiofrequency on Periorbital SkinDERMATOLOGIC SURGERY, Issue 2 2004Javier Ruiz-esparza MDArticle first published online: 3 FEB 200 Background. Laxity and rhytids of the lower eyelids are common cosmetic concerns. Historically, correction has either been surgical through either transcutaneous or transconjunctival blepharoplasty or ablative through laser resurfacing or chemical peeling. Therapeutic options usually require significant postoperative healing and have the potential risk of scarring ectropion or pigmentary loss. Objective. To report the use of a new technique that uses nonablative radiofrequency (NARF) to tighten noninvasively and nonsurgically the flaccid skin of the lower eyelids by treating the periorbital area to produce cosmetic improvement. Methods. Nine patients with skin flaccidity of the lower eyelids had a single treatment session with NARF in a small area of skin in the periorbital region, specifically the zygomatic and/or temporal areas. All patients were treated with topical anesthesia only. The treatment lasted approximately 10 minutes. No postoperative care was required. Results. All of the nine patients in the study achieved cosmetic improvement of the eyelids ostensibly through skin contraction. All patients were able to return to their normal routines immediately. Although the results were gradual, patient satisfaction was remarkable. No complications were seen in this study. Conclusion. This new procedure using NARF was successful in providing a safe, noninvasive, cosmetic improvement in these patients with excessive skin laxity of the lower eyelids. Postoperative morbidity, including down time and complications, was not seen. [source] The Art of Repair in Surgical Hair Restoration Part I: Basic Repair StrategiesDERMATOLOGIC SURGERY, Issue 9 2002Robert M. Bernstein MD background. An increasingly important part of many hair restoration practices is the correction of hair transplants that were performed using older, outdated methods, or the correction of hair transplants that have left disfiguring results. The skill and judgment involved in these repair procedures often exceed those needed to operate on patients who have had no prior surgery. The use of small grafts alone does not protect the patient from poor work. Errors in surgical and aesthetic judgment, performing procedures on noncandidate patients, and the failure to communicate successfully with patients about realistic expectations remain major problems. objective. This two-part series presents new insights into repair strategies and expands upon several techniques previously described in the hair restoration literature. The focus is on creative aesthetic solutions to solve the supply/demand limitations inherent in most repairs. This article is written to serve as a guide for surgeons who perform repairs in their daily practices. methods. The repairs are performed by excision with reimplantation and/or by camouflage. Follicular unit transplantation is used for the restorative aspects of the procedure. results. Using punch or linear excision techniques allows the surgeon to relocate poorly planted grafts to areas that are more appropriate. In special situations, removal of grafts without reimplantation can be accomplished using lasers or electrolysis. The key elements of camouflage include creating a deep zone of follicular units, angling grafts in their natural direction, and using forward and side weighting of grafts to increase the appearance of fullness. The available donor supply is limited by hair density, scalp laxity, and scar placement. conclusion. Presented with significant cosmetic problems and severely limited donor reserves, the surgeon performing restorative hair transplantation work faces distinct challenges. Meticulous surgical techniques and optimal utilization of a limited hair supply will enable the surgeon to achieve the best possible cosmetic results for patients requiring repairs. [source] The Laser-Assisted Neck Lift: Modifications in Technique and Postoperative Care to Improve ResultsDERMATOLOGIC SURGERY, Issue 6 2002F. Richard Noodleman MD background. Conventional submental tumescent liposuction has proved disappointing for some patients with anterior neck laxity, ptotic platysma muscles, and increased subplatysmal fat. Many of these patients are facelift candidates but are unwilling to undergo this extensive procedure. We describe our hybrid approach, which offers consistently improved results and enhanced patient satisfaction. objective. To establish a sharper cervicomental angle by more completely removing subplatysmal fat. We also wished to achieve more consistent, smoother results, minimizing ripples, folds, and hematomas with a novel postoperative dressing system. methods. Extensive tumescent liposuction of the lower face, jowls, and anterior neck was performed. Following this, subplatysmal fat was removed by dissection, the platysma muscle was imbricated, and the CO2 laser utilized in a defocused, low-power mode to partially treat the dermal undersurface and underlying muscle. Our postoperative dressing included a 10 cm mineral oil polymer gel disc in the submental location, covered by tape, silicone foam, and a lower face and neck garment to provide both support and even compression over the entire neck for at least the first 24 hours. results. Results proved uniformly satisfying for most patients, even those in their senior years. Benefits included an improved cervicomental angle, a decrease in jowling, and a marked reduction in the laxity and wrinkling of the neck skin and horizontal neck creases. Problems related to postoperative rippling or folding of the redraped skin and hematoma formation were minimized. conclusion. Laser neck tightening combined with tumescent liposuction and an advanced postoperative dressing for superior support and uniform compression has resulted in consistently excellent outcomes with improved patient satisfaction. [source] Modified Burow's Wedge Flap for Upper Lateral Lip DefectsDERMATOLOGIC SURGERY, Issue 5 2000Minh Dang MD Background. There are fundamental concepts we use in managing surgical defects. Whether planning a primary closure or a local flap, we frequently modify the basic design to maximize aesthetic outcomes, taking into consideration a number of factors including the location of the defect and tissue availability. Objective. We describe a modified Burow's wedge flap for upper lateral lip defects. Method. Report of an illustrated case. Result. A patient with an upper lip defect was successfully reconstructed using the modified Burow's wedge flap, where the Burrow's wedge is placed on the mucocutaneous lip. Conclusion. Certain modifications of commonly used reconstructive techniques can be utilized in specific situations to enhance cosmesis. For the Burow's wedge flap, the dermatologic surgeon has several options in placing the Burow's triangle. This is an example of how alternatives in a closure can be used depending on the laxity of the skin and the size of the defect. Advantages and disadvantages of this alternative placement of the Burow's triangle are discussed. [source] Fractional CO2 laser: a novel therapeutic device upon photobiomodulation of tissue remodeling and cytokine pathway of tissue repairDERMATOLOGIC THERAPY, Issue 2009F. Prignano ABSTRACT Minimally ablative fractional laser devices have gained acceptance as a preferred method for skin resurfacing. Notable improvements in facial rhytides, photodamage, acne scarring, and skin laxity have been reported. The aim of the present work was to compare how different CO2 laser fluences, by modulating the secretory pathway of cytokines, are able to influence the wound-healing process, and how these fluences are associated with different clinical results. Eighteen patients, all with photodamaged skin, were treated using a fractional CO2 laser (SmartXide DOT, Deka M.E.L.A., Florence, Italy) with varying laser fluences (2.07, 2.77, and 4.15 J/cm2). An immunocytochemical study was performed at defined end points in order to obtain information about specific cytokines of the microenvironment before and after treatment. The secretory pathway of cytokines changed depending on the re-epithelization and the different laser fluences. Different but significant improvements in wrinkles, skin texture, and hyperpigmentation were definitely obtained when using 2.07, 2.77, and 4.15 J/cm2, indicating fractional CO2 laser as a valuable tool in photorejuvenation with good clinical results, rapid downtime, and an excellent safety profile. [source] Influence of environmental stress on skin tone, color and melanogenesis in Japanese skinINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 1 2005K. Kikuchi Introduction It is needless to say that one of the most potent environmental stress for melanogenesis of the human skin is the effect of ultraviolet (UV) light from the sunlight. Characteristic skin aging as a result of this UV light is recognized as photoaging. Clinical features in photoaging are wrinkles, skin laxity, coarseness, leathery, yellowing, lentigenes, mottled pigmentation, telangiectasia, sebaceous hypertrophy and purpura. There is an apparent difference in clinical features in photoaging among different races, i.e. between Caucasians, African American and Asians that include Japanese. Not only photo skin type but also environmental factors, such as climate, latitude, altitude and their habit of sunbathing, smoking and skin care influence the characteristic development of their photoaging. Racial difference in photoaging Caucasians tend to develop skin laxity and fine wrinkles more than Asians [1]. Asians tend to produce coarser wrinkles than the Caucasians although their development is rather late in life. There is also a difference in the skin color. Pigmentation is an earliest and prominent skin changes in Asians [1] and it increases with age [2]. In contrast, pigmentation is not apparent in the Caucasians although redness probably because of an increase in cutaneous vascularization becomes prominent in middle aged Caucasians [2]. Chung reported that seborrheic keratosis is a major pigmentary lesion in men, whereas hyperpigmented macules are prominent features in women in Koreans [3]. Melanogenesis pigmentation disorders in Japanese Ephelides (freckles) are commonly found in those with photo skin type I who have fair skin and red eyes and blond hair. They are also found in the Japanese. Clinical feature reveals that multiple small pigmentary macules on sun-exposed areas mainly on the mid-portion of the face. These lesions seem to be familial, becoming apparent even in early childhood after sun exposure. Melasma is an acquired pigmentary disorder commonly found in middle aged Japanese women characterized by irregular brown macules and patches on the sun-exposed areas on the face typically as bilaterally present macules on the cheeks. An increase in sex hormones as a result of pregnancy and intake of contraceptive pills is one of the etiological factors to develop melasma. Sun exposure also worsens it. Nevus of Ota is also a common pigmentary disorder found in the Japanese. It is usually unilateral, blue-brown to slate-gray pigmentary macules on the eyelid and cheek that appear in early childhood or in puberty. Acquired dermal melanocytosis is also a pigmentary disorder, in which dermal melanocytes are found as shown in nevus of Ota, characterized by bilateral brown to blue-gray macules on the forehead, temple, eyelid and malar areas in middle aged Japanese women. This tends to be misdiagnosed as melasma. Solar lentigo is an acquired pigmented macule induced by sun exposure. Solar lentigines are usually multiple, circumscribed brown macules. There are two types of solar lentigo. One is a small macular type, characterized by multiple, small brown macules whose diameter is less than 5 mm, being similar to ephelides (freckles). The other type is a large macular type, characterized by a few round to oval, brown macules whose diameter is beyond 1 cm. Some of their surface are hyperkeratotic and become elevated to produce seborrheic keratosis. Again, the early sign of photoaging in Japanese is pigmentated spots and these pigmentation disorders increase with age. Among the pigmentary changes, nevus of Ota, acquired dermal melanocytosis, melasma and large macular type of solar lentigo are characteristic skin changes found in the Japanese in addition to ephelides and small macular type of solar lentigo. Seasonal changes of the various functional properties of the skin including skin color assessed by non-invasive bioengineering techniques [4]. When we consider skin tone, color and melanogenesis, UV light from the sunlight is the most potent environmental stress, although we cannot forget also the important influence of environmental relative humidity affects our skin functions as well as its appearance. We investigated seasonal influences on the various properties of the skin in 39 healthy Japanese females consisting of different age groups. Their skin is thought to be affected by the UV light in summer, and by the exposure to the dry and cold air in winter. Materials and methods Biophysical, non-invasive measurements, including transepidermal water loss (TEWL) as a parameter for the barrier function of the stratum corneum (SC), high frequency conductance as a parameter for the hydration state of the SC, skin color and casual surface lipid levels, were conducted during late summer and winter months. Skin color was determined with a chromameter according to the L*a*b* CIE 1976 system, where L* is an attribute on the luminance scale, a* that on the red versus green scale and b* that on the yellow versus blue scale. All the measurements were conducted in an environment controlled-chamber (21 ± 1 °C room temperature, and 50 ± 3% relative humidity). Results The barrier function of the SC was found to be significantly impaired in winter on the cheek as compared with that measured in summer, whereas no such seasonal change was apparent both in the hydration state of the SC and sebum levels on the cheek. In the assessment of the skin color on the cheek, a significant increase in a* (redness) and a decrease in b* (yellowness) were observed in winter. In contrast, on the flexor forearm, the values of L* (luminescence) increased in winter, but no seasonal change was noted in the values of a* and b*. In this study, skin changes with aging were also found by the non-invasive bioengineering methods. The value of TEWL on the cheek tended to increase with age, whereas no significant change was observed in the value of TEWL on the forearm. In the assessment of skin color, b* value on the cheek significantly increased with age whereas a* and L* values on the cheek did not show any significant change with age. Summary of this study We think that such an increase in yellowness with aging of the cheek skin is a phenomenon unique to the Japanese (Asians) since an increase in b* value was not observed in Caucasians [2]. The facial skin that is always exposed shows barrier impairment in a dry and cold winter environment and demonstrates increased yellowness in skin color because of a prolonged exposure to the UV light from the sun in the summer season. The non-invasive bioengineering methods are useful to demonstrate even invisible seasonal changes occurring in the same individuals and changes with age occurring in the skin. References 1.,Goh, S.H. The treatment of visible signs of senescence: the Asian experience. Br. J. Dermatol.122, 105,109 (1990). 2.,LeFur, I., Numagami, K., Guinot, C. et al. Age-related reference values of skin color in Caucasian and Japanese healthy women according to skin site. Pigment Cell Res. 7, 67 (1999). 3.,Chung, J.H., Lee, S.H., Youn, C.S. et al. Cutaneous photodamage in Koreans: influence of sex, sun exposure, smoking, and skin color. Arch. Dermatol. 137, 1043,1051 (2001). 4.,Kikuchi, K., Kobayashi, H., Le Fur, I. et al. Winter season affects more severely the facial skin than the forearm skin: comparative biophysical studies conducted in the same Japanese females in later summer and winter. Exog. Dermatol. 1, 32,38 (2002). [source] Acquired localized cutis laxa confined to the face: case report and review of the literatureINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 12 2004Claudia Jimena Perafán Riveros MD Background, Cutis laxa is an uncommon entity characterized by laxity of the skin, which hangs in loose folds, producing the appearance of premature aging. It can be subdivided into congenital and acquired. This latter variant is rare and the skin involvement varies from generalized to localized. We report a case of a localized acquired cutis laxa confined to the face, without preceding inflammatory lesions or systemic compromise. Four similar cases have been reported to date. The etiology remains unknown and there is no definitive treatment. Methods, A 27-year-old White woman came to our hospital with a wrinkled face, pendulous earlobes and drop eyelids. Changes began 5 years prior, and she appeared much older than her age. Results, Histological analysis and ultrastructural examination of skin biopsy revealed reduction and fragmentation of elastic fibers, confirming the diagnosis of cutis laxa. No systemic involvement was diagnosed. The patient was submitted to plastic surgery for repair, with satisfactory results to date. Conclusions, Acquired localized cutis laxa confined to the face without preceding inflammatory lesions is extremely rare. The etiology remains unknown. Clinical features and histopathologic findings confirm the diagnosis. Surgical repair seems to be the only therapeutic choice, but the results are variable and temporary. [source] Clinical manifestations of chondromalacia patella in 260 Iranian patientsINTERNATIONAL JOURNAL OF RHEUMATIC DISEASES, Issue 2 2005I. SALEHI Abstract Background and aim:, Chondromalacia patella, which is characterized by softening of the patellar cartilage, is the most common cause of anterior knee pain in young women. The aim of this study was to identify the clinical features of patients with chondromalacia patella in Iran. Methods:, All patients under 40 years, complaining of mechanical knee pain who were referred to Amir A'lam Rheumatology Unit, with positive shrug sign and normal knee X-rays during the period September 2000 to September 2002, were included in this study. After physical examination and knee radiography, patients with knee arthritis, knee osteoarthritis and knee periarthritis were excluded. Patients with the clinical diagnosis of chondromalacia patella were studied. The demographic data, clinical disease characteristics and disease course were recorded. Results:, There were 260 patients. They were predominantly female (F : M, 2.6 : 1), in the third decade of life and a mean age of 22.8 years at the onset of disease. Bilateral involvement was found in 92% of patients. The first manifestation was knee pain. The history of trauma or swelling of the knee occurred in about 20% of cases. The history of dislocation was 3%. Sitting with flexed knees, stairs, and the use of Turkish WCs aggravated the knee pain. About one-third had knee malalignment, mostly mild genu varus. Patella alta was seen in 1.6%. Q-angle more than 15° was seen in 90.8%. Mean Q-angle was 21.9°, mean patellar angle was 122.6°, and mean intercondylar angle was 141.5°. All patients had the shrug sign. About 90% had Rabot test and crepitation, 3.5% had knee effusion, and 1% had knee laxity. Lower limb discrepancy was seen in 6.2% and spinal deformity in 10%. Ninety-three percent of the patients were treated by conservative (medical) therapy. Conclusion:, So the classic case of chondromalacia patella is a woman in her third decade of life with mechanical knee pain and positive shrug test. [source] Type V Osteogenesis Imperfecta: A New Form of Brittle Bone Disease,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 9 2000Francis H. Glorieux Abstract Osteogenesis imperfecta (OI) is commonly subdivided into four clinical types. Among these, OI type IV clearly represents a heterogeneous group of disorders. Here we describe 7 OI patients (3 girls), who would typically be classified as having OI type IV but who can be distinguished from other type IV patients. We propose to call this disease entity OI type V. These children had a history of moderate to severe increased fragility of long bones and vertebral bodies. Four patients had experienced at least one episode of hyperplastic callus formation. The family history was positive for OI in 3 patients, with an autosomal dominant pattern of inheritance. All type V patients had limitations in the range of pronation/supination in one or both forearms, associated with a radiologically apparent calcification of the interosseous membrane. Three patients had anterior dislocation of the radial head. A radiodense metaphyseal band immediately adjacent to the growth plate was a constant feature in growing patients. Lumbar spine bone mineral density was low and similar to age-matched patients with OI type IV. None of the type V patients presented blue sclerae or dentinogenesis imperfecta, but ligamentous laxity was similar to that in patients with OI type IV. Levels of biochemical markers of bone metabolism generally were within the reference range, but serum alkaline phosphatase and urinary collagen type I N-telopeptide excretion increased markedly during periods of active hyperplastic callus formation. Qualitative histology of iliac biopsy specimens showed that lamellae were arranged in an irregular fashion or had a meshlike appearance. Quantitative histomorphometry revealed decreased amounts of cortical and cancellous bone, like in OI type IV. However, in contrast to OI type IV, parameters that reflect remodeling activation on cancellous bone were mostly normal in OI type V, while parameters reflecting bone formation processes in individual remodeling sites were clearly decreased. Mutation screening of the coding regions and exon/intron boundaries of both collagen type I genes did not reveal any mutations affecting glycine codons or splice sites. In conclusion, OI type V is a new form of autosomal dominant OI, which does not appear to be associated with collagen type I mutations. The genetic defect underlying this disease remains to be elucidated. [source] A comparison of cyclic variations in anterior knee laxity, genu recurvatum, and general joint laxity across the menstrual cycleJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 11 2010Sandra J. Shultz Abstract Changes in anterior knee laxity (AKL), genu recurvatum (GR) and general joint laxity (GJL) were quantified across days of the early follicular and early luteal phases of the menstrual cycle in 66 females, and the similarity in their pattern of cyclic variations examined. Laxity was measured on each of the first 6 days of menses (M1,M6) and the first 8 days following ovulation (L1,L8) over two cycles. The largest mean differences were observed between L5 and L8 for AKL (0.32,mm), and between L5 and M1 for GR (0.56°) and GJL (0.26) (p,<,0.013). At the individual level, mean absolute cyclic changes in AKL (1.8,±,0.7,mm, 1.6,±,0.7,mm), GR (2.8,±,1.0°, 2.4,±,1.0°), and GJL (1.1,±,1.1, 0.7,±,1.0) were more apparent, with minimum, maximum and delta values being quite consistent from month to month (ICC2,3,=,0.51,0.98). Although the average daily pattern of change in laxity was quite similar between variables (Spearman correlation range 0.61 and 0.90), correlations between laxity measures at the individual level were much lower (range ,0.07 to 0.43). Substantial, similar, and reproducible cyclic changes in AKL, GR, and GJL were observed across the menstrual cycle, with the magnitude and pattern of cyclic changes varying considerably among females. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:1411,1417, 2010 [source] Muscle stabilization strategies in people with medial knee osteoarthritis: The effect of instabilityJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 9 2008Laura C. Schmitt Abstract The sensation of knee instability (shifting, buckling. and giving way) is common in people with medial knee osteoarthritis (OA). Its influence on knee stabilization strategies is unknown. This study investigated the influence of knee instability on muscle activation during walking when knee stability was challenged. Twenty people with medial knee OA participated and were grouped as OA Stable (OAS) (n,=,10) and OA Unstable (OAU) (n,=,10) based on self-reported knee instability during daily activities. Quadriceps strength, passive knee laxity, and varus alignment were assessed and related to knee instability and muscle cocontraction during walking when the support surface translated laterally. Few differences in knee joint kinematics between the groups were seen; however, there were pronounced differences in muscle activation. The OAU group used greater medial muscle cocontraction before, during, and following the lateral translation. Self-reported knee instability predicted medial muscle cocontraction, but medial laxity and limb alignment did not. The higher muscle cocontraction used by the OAU subjects appears to be an ineffective strategy to stabilize the knee. Instability and high cocontraction can be detrimental to joint integrity, and should be the focus of future research. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1180,1185, 2008 [source] Generation of tendon-to-bone interface "enthesis" with use of recombinant BMP-2 in a rabbit modelJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 11 2007Yusuke Hashimoto Abstract The anatomical structure at bone-tendon and bone-ligament interfaces is called the enthesis. Histologically, the enthesis is characterized by a transitional series of tissue layers from the end of the tendon to bone, including tendon, fibrocartilage, calcified fibrocartilage, and bone. This arrangement yields stronger direct connection of the soft tissues to bone. In surgical repair, the enthesis has proven difficult to reproduce, and the success of ligament-bone bonding has depended on the fibrous attachment that forms after any ligament reconstructions. In this study, we attempted to generate a direct-insertion enthesis in two stages. First, recombinant human bone morphogenetic protein-2 (rhBMP-2) was injected into the flexor digitorum communis tendon in the rabbit hind limb to induce ectopic ossicle formation. In a second step, the resultant tendon/ossicle complex was then surgically transferred onto the surface of the rabbit tibia to generate a stable tendon-bone junction. One month following surgery, histomorphological examination confirmed direct insertion of tendon-bone structures in the proximal tibia of the rabbit. Ultimate failure loads of the BMP-2-generated tendon-bone junction were significantly higher than in the control group (p,<,0.01). These findings suggest that it is possible to successfully regenerate a direct tendon-to-bone enthesis. Use of this approach may enable successful reconstruction of joints rendered unstable after ligamentous rupture or laxity after anterior cruciate ligament injury. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:1415,1424, 2007 [source] Measurement of varus,valgus and internal,external rotational knee laxities in vivo,Part II: relationship with anterior,posterior and general joint laxity in males and femalesJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 8 2007Sandra J. Shultz Abstract We examined sex differences in general joint laxity (GJL), and anterior,posterior displacement (ANT,POST), varus,valgus rotation (VR,VL), and internal,external rotation (INT,EXT) knee laxities, and determined whether greater ANT and GJL predicted greater VR,VL and INT,EXT. Twenty subjects were measured for GJL, and scored on a scale of 0,9. ANT and POST were measured using a standard knee arthrometer at 133 N. VR,VL and INT,EXT were measured using a custom joint laxity testing device, defined as the angular displacements (deg) of the tibia relative to the femur produced by 0,10 Nm of varus,valgus torques, and 0,5 Nm of internal,external torques, respectively. INT,EXT were measured during both non-weight-bearing (NWB) and weight-bearing (WB,=,40% body weight) conditions while VR,VL were measured NWB. All laxity measures were greater for females compared to males except for POST. ANT and GJL positively predicted 62.5% of the variance in VR,VL and 41.8% of the variance in WB INT,EXT. ANT was the sole predictor of INT,EXT in NWB, explaining 42.3% of the variance. These findings suggest that subjects who score higher on clinical measures of GJL and ANT are also likely to have greater VR,VL and INT,EXT knee laxities. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:989,996, 2007 [source] Medial collateral ligament insertion site and contact forces in the ACL-deficient kneeJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2006Benjamin J. Ellis Abstract The objectives of this research were to determine the effects of anterior cruciate ligament (ACL) deficiency on medial collateral ligament (MCL) insertion site and contact forces during anterior tibial loading and valgus loading using a combined experimental-finite element (FE) approach. Our hypothesis was that ACL deficiency would increase MCL insertion site forces at the attachments to the tibia and femur and increase contact forces between the MCL and these bones. Six male knees were subjected to varus,valgus and anterior,posterior loading at flexion angles of ,0° and 30°. Three-dimensional joint kinematics and MCL strains were recorded during kinematic testing. Following testing, the MCL of each knee was removed to establish a stress-free reference configuration. An FE model of the femur,MCL,tibia complex was constructed for each knee to simulate valgus rotation and anterior translation at 0° and 30°, using subject-specific bone and ligament geometry and joint kinematics. A transversely isotropic hyperelastic material model with average material coefficients taken from a previous study was used to represent the MCL. Subject-specific MCL in situ strain distributions were used in each model. Insertion site and contact forces were determined from the FE analyses. FE predictions were validated by comparing MCL fiber strains to experimental measurements. The subject-specific FE predictions of MCL fiber stretch correlated well with the experimentally measured values (R2,=,0.95). ACL deficiency caused a significant increase in MCL insertion site and contact forces in response to anterior tibial loading. In contrast, ACL deficiency did not significantly increase MCL insertion site and contact forces in response to valgus loading, demonstrating that the ACL is not a restraint to valgus rotation in knees that have an intact MCL. When evaluating valgus laxity in the ACL-deficient knee, increased valgus laxity indicates a compromised MCL. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source] Nonweight-bearing anterior knee laxity is related to anterior tibial translation during transition from nonweight bearing to weight bearingJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 3 2006Sandra J. Shultz Abstract We examined the relationship between anterior knee laxity (AKL), evaluated while the knee was nonweight bearing, and anterior translation of the tibia relative to the femur (ATT), evaluated when the knee transitioned from nonweight-bearing to weight-bearing conditions in response to an applied compressive load at the foot. Twenty subjects with normal knees (10 M, 10 F; 25.2,±,4.1 years, 169.8,±,11.5 cm, 71.6,±,16.9 kg) underwent measurements of AKL and ATT of the right knee on 2 days. AKL was measured at 133N with the KT-2000Ô. ATT was measured with the Vermont Knee Laxity Device and electromagnetic position sensors attached to the patella and the anteromedial aspect of the proximal tibia. Three trials for each measure were averaged and analyzed. Measurement consistency was high for both AKL (ICC,=,0.97; SEM,=,0.44 mm) and ATT (ICC,=,0.88; SEM,=,0.84 mm). Linear regression revealed that AKL predicted 35.5% of the variance in ATT (p,=,0.006), with a prediction equation of YATT,=,3.20,+,0.543(XAKL). Our findings suggest that increased AKL is associated with increased ATT as the knee transitions from nonweight-bearing to weight-bearing conditions. The potential for increased knee joint laxity to disrupt normal knee biomechanics during activities such as landing from a jump, or the foot strike phase of gait deserves further study. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:516,523, 2006 [source] Absolute serum hormone levels predict the magnitude of change in anterior knee laxity across the menstrual cycleJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 2 2006Sandra J. Shultz Abstract This study aimed to determine whether absolute sex hormone concentrations predict the magnitude of knee joint laxity changes across the menstrual cycle. Twenty-two females (18,30 years, body mass index ,30), who reported normal menstrual cycles for the previous 6 months were tested daily across one complete menstrual cycle for serum levels of estradiol (E,=,pg/mL), progesterone (P,=,ng/mL), and testosterone (T,=,ng/dL), and knee joint laxity (KLax,=,mm displacement at 134N) measured with a standard knee arthrometer. The change in KLax across the cycle (maximum,minimum), and minimum (early follicular) and peak (postovulatory) hormone concentrations were recorded for each subject. A stepwise linear regression determined if the minimum, peak, or absolute change in hormone concentrations would predict the magnitude of change in KLax across the cycle. KLax changed on average 3.2,±,1.1 mm across the menstrual cycle (range, 1.5,5.3 mm). Minimum levels of E (39.9,±,11.8 pg/mL) and P (0.61,±,0.27 ng/mL), coupled with peak concentrations of E (199.6,±,54.9 pg/mL) and T (22.5,±,10.5 ng/dL) explained 57.6% of the change in KLax across the cycle. Greater absolute changes in KLax were observed in response to peak E and T levels when minimum E concentrations were lower and minimum P concentrations were higher in the early follicular phase. The absolute minimum concentrations of E and P in the early follicular phase appear to be important factors in determining the sensitivity of the knee joint's response to changing hormone levels. © 2005 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source] An investigation to examine the inter-tester and intra-tester reliability of the Rolimeter® knee tester, and its sensitivity in identifying knee joint laxityJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 6 2005Julian Hatcher Abstract Purpose: The purpose of this study is to evaluate the Rolimeter® knee tester (Aircast®, Europe) as reliable and clinically sensitive tool for identifying and quantifying knee joint laxity utilising a sample of both known ACLD and normal knees. Methods: Thirty matched subjects (15 known ACLD and 15 normal subjects) were tested for knee joint laxity using the Rolimeter®. Each subject was measured at both 90° and 30° of knee flexion, by each of the six investigators. This was then repeated again by all six investigators so that inter-tester and intra-tester reliability could be examined. Results: Results showed that there was good reliability between testers, and intra-tester reliability was good for both left and right knees in both 90° and 30° of flexion. Results also demonstrated a high level of sensitivity for determining knee joint laxity in ACLD compared to normal knees. Conclusion: The Rolimeter® knee tester is a reliable device for quantifying knee joint laxity, and is sensitive enough to identify anterior cruciate ligament deficiency. © 2005 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source] Biomechanical effects of medial,lateral tibial tunnel placement in posterior cruciate ligament reconstructionJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 1 2003Keith L. Markolf With most posterior cruciate (PCL) reconstruction techniques, the distal end of the graft is fixed within a tibial bone tunnel. Although a surgical goal is to locate this tunnel at the center of the PCL's tibial footprint, errors in medial,lateral tunnel placement of the tibial drill guide are possible because the position of the tip of the guide relative to the PCL's tibial footprint can be difficult to visualize from the standard arthroscopy portals. This study was designed to measure changes in knee laxity and graft forces resulting from mal-position of the tibial tunnel medial and lateral to the center of the PCL's tibial insertion. Bone,patellar tendon,bone allografts were inserted into three separate tibial tunnels drilled into each of 10 fresh-frozen knee specimens. Drilling the tibial tunnel 5 mm medial or lateral to the center of the PCL's tibial footprint had no significant effect on knee laxities: the graft pretension necessary to restore normal laxity at 90° of knee flexion (laxity match pretension) with the medial tunnel was 13.8 N (29%) greater than with the central tunnel. During passive knee flexion,extension, graft forces with the medial tibial tunnel were significantly higher than those with the central tunnel for flexion angles greater than 65° while graft forces with the central tibial tunnel were not significantly different than those with the lateral tibial tunnel. Graft forces with medial and lateral tunnels were not significantly different from those with a central tunnel for 100 N applied posterior tibial force, 5 N m applied varus and valgus moment, and 5 N m applied internal and external tibial torque. With the exception of slightly higher graft forces recorded with the medial tunnel beyond 65° of passive knee flexion, errors in medial,lateral placement of the tibial tunnel would not appear to have important effects on the biomechanical characteristics of the reconstructed knee. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] Healing of subfailure ligament injury: comparison between immature and mature ligaments in a rat modelJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2002Paolo P. Provenzano This study evaluated biomechanical properties of healing ligament following subfailure (grade II) injury by comparing young and mature animals in a rat lateral collateral ligament (LCL) model. One randomly selected LCL was stretched in situ using a custom designed device in eighteen young (21 days) and eighteen skeletally mature (8 months) male rats. Animals were euthanized at 0, 7, and 14 days post-surgery, and ligament ultimate stress, strain at failure and laxity were determined (n = 6 pairs per group). At time 0 after introduction of stretch injury, ligament laxity was present in both groups. The mature rats had 54 ± 9% strength of the control while the immature rats had 58 ± 11% of the strength of the control, representing a consistent and significant injury. The immature and mature ligaments showed similar patterns of cellular damage post-injury and had similar modes of mechanical failure. Ligament laxity decreased in each group as healing time increased, however ligament laxity did not completely recover in either group after 2 weeks of healing. After 7 and 14 days of healing, the mature rats, respectively, had only 63 ± 14% and 80 ± 8% strengths of the controls while the immature rats had 94 ± 6% and 94 ± 10%. Hence, mechanical data showed that immature animals recovered their strength after a grade II sprain at a faster rate than mature animals. However, ligament laxity was still present in both groups two weeks after the injury and was not completely removed by growth in the immature group. These findings are clinically relevant since joint laxity after injury is common, and these results may explain the presence of continued instability in a joint injured at a young age. Hence, this study, with a new injury model, showed differences in ligament healing associated with maturity and quantified the clinically observed persistance of ligament laxity. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] | ||||||||||||||||||||||||||||