Injury metrics are altered in spica-casted versus non-casted child ATDs in side-impact collisions with door intrusion.

Objective: There is little data defining safe transport protocols for spica-casted children. A single earlier study demonstrated the presence of a body cast alters kinematics and injury metrics during simulated side-impact crashes. Since then, the National Highway Transportation Safety Administration (NHTSA) proposed a new side-impact test protocol for evaluating child restraints. This test is more severe than the earlier tests, as it simulates an impact with a door intruding into the occupant space. As no currently available child restraint system (CRS) able to accommodate a spica-casted child has been evaluated using these updated testing criteria, the objective of this study was to evaluate current restraint options in simulated side-impact collisions using an anthropomorphic test device (ATD) modeled after a 3-year-old.Methods: Four commercially available CRSs able to accommodate a spica-casted Q3s side-impact ATD were selected for testing. Side-impact testing was performed using casted and uncasted ATDs in compliance with the NHTSA proposed side-impact test. High-speed photography and ATD instrumentation were used to measure selected injury criteria.Results: HIC15 values were highest in CRSs with less robust side wings, such as the Merritt WallenburgTM (HIC15 = 1,373), which allow for the occupant to interact with the intruding door panel. Head contact with the door panel was found to correspond with high resultant neck peak force. Pelvic acceleration magnitudes were greatest for the uncasted tests. Casted tests with a CRS that included an armrest were associated with greater torso rotation in the frontal plane with the left shoulder moving toward the door panel.Conclusions: The presence of a spica cast alters injury metrics in side-impact testing. Spica specific child safety seats are not yet optimized for side-impact with door intrusion. This is due to a lack of adequate side cushion wings, which may place both casted and uncasted occupants at increased likelihood for injury through head contact with an intruding door. Additional work is needed to improve the safety of CRSs for both casted and uncasted children in side-impact collisions.

The Return on Investment of Orthopaedic Fellowship Training: A Ten-year Update.

BACKGROUND: Over 90% of graduating orthopaedic residents now pursue fellowship training, and only 15% of practicing orthopaedic surgeons now characterize themselves as generalists. Fellowship training has significant financial effects due to both opportunity cost of that year of training and changes in compensation throughout one's career. The purpose of this study was to estimate the financial return on investment by pursuing additional training in an orthopaedic fellowship versus general practice. METHODS: Using described techniques of financial analysis, net present value (NPV), internal rate of return (IRR), and break-even point were estimated over the average working career length of an orthopaedic surgeon. Compensation data were drawn from the American Medical Group Association physician compensation surveys. Seven fellowships were studied and referenced to a career in general orthopaedic practice. RESULTS: Fellowship training in spine surgery yields the highest return on investment with a break-even point of 5 years. Adult reconstruction has a positive NPV and IRR, but when corrected for number of hours worked per week offers no productivity advantage to general practice. Sports medicine and trauma offer neutral returns, but when corrected for work hours, NPV and IRR both become negative. Hand, pediatrics, and foot and ankle never break even following the loss of compensation realized during fellowship year. DISCUSSION: The recent trend across all medical specialties has been for increased fellowship training and subspecialization. There are numerous reasons to pursue fellowship training, both personal and financial. This study presents an updated estimate of the financial impact of fellowship training in orthopaedics. This analysis demonstrates that selecting different fellowships can generate positive, negative, or neutral financial returns. This study has the potential to influence residents' decisions to pursue general practice versus fellowship training and identifies economic drivers, which may lead to preferential pursuit of certain subspecialties.

Frontal Crash Injury Metrics Are Below Mandated Limits for a Spica Casted Child Dummy in Currently Available Restraints.

BACKGROUND: There is a paucity of data defining safe transport protocols for children treated with hip spica casting. Although restraint devices for casted children are available, all federally mandated testing uses a noncasted anthropomorphic test device (ATD or crash dummy). The purpose of this study was to evaluate current restraint options in simulated frontal crash testing using a casted pediatric ATD to determine injury risk to the head, cervical spine, chest, and pelvis. METHODS: Using a 3-year-old ATD, dynamic crash sled tests simulating frontal crash were performed in accordance with government safety standards. The ATD was casted in a double-leg spica and the following restraint devices were tested: a seat designed for spica casted children, a restraint vest-harness, a traditional booster seat, and 2 traditional forward-facing car seats. RESULTS: Although the presence of the cast increased many of the injury metrics measured, all seats passed current federal guidelines for the head and chest. No single seat performed best in all metrics. The greatest magnitude of neck loading and second-highest head injury criterion values were observed for the booster seat. The vest-harness produced the highest head injury criterion and the chest compression exceeded proposed federal limits. CONCLUSIONS: The results suggest safe transport in commercially available seats is possible with the child properly restrained in a correctly fitting seat. However, parents should not assume a child restraint system is appropriate for use just based on fit as, for example, seats with harnesses outperformed an easy to fit booster seat. CLINICAL RELEVANCE: Each child and the position of the child's cast are unique and discharge planning involves consideration of safe transportation. Although this study suggests several seats used to transport spica casted children pass the federal head and chest injury prevention requirements, it is important to recognize that some children may still require emergency vehicle transport.

Optimizing Hybrid Plate Fixation with a Locked, Oblique End Screw in Osteoporotic Fractures.

BACKGROUND: The end screw in a fracture plate creates the greatest resistance to bending. For osteoporotic fractures treated with plates, there is some question as to the optimal screw insertion technique for the screw farthest from the fracture. A locked, oblique end screw was previously shown to increase resistance to periprosthetic fracture. It is unknown, however, how this end screw configuration would resist pullout when subjected to bending. METHODS: Narrow, low contact 3.5 mm locking compression plates with 6 and 12 holes were anchored to simulated bone material with material properties representing osteoporotic bone. Four configurations were evaluated for the end screw: perpendicular and angulated 30 degrees away from the fracture for both non-locked and locked screws (n=6 per group). The constructs were subjected to 3 point bending until the peak load and finally total construct failure was achieved. RESULTS: Peak force, stiffness, energy to peak load, and the failure mode of each construct were determined. All four 12-hole construct groups failed by gross plastic bending deformation of the plate at the fulcrum past a previously established clinically relevant limit for failure (15°). All 12-hole plate constructs failed at statistically higher loads and energy than any of the 6-hole plate constructs, with the exception of the 6-hole locked, oblique construct. CONCLUSION: The locked, oblique end screw provides equivalent pull out strength for 3.5 mm low contact plates regardless of plate length. Combined with its resistance to periprosthetic fracture, this end screw configuration appears to be the best option for the construct integrity of hybrid plating for osteoporotic fractures. CLINICAL RELEVANCE: Osteoporotic fractures are challenging to treat. The current study and the existing literature show that resistance to both bending loads and refracture at the end of a plate are minimized with a locked screw angled away from the fracture.

Temporal Variation in Ankle Fractures and Orthopedic Resident Program Planning in an Urban Level 1 Trauma Center.

Previous studies have described the mechanism of ankle fractures, their seasonal variation, and fracture patterns but never in conjunction. In addition, the cohorts previously studied were either not from trauma centers or were often dominated by low-energy mechanisms. The present study aimed to describe the epidemiology of ankle fractures presenting to an urban level 1 trauma center. The records from an urban level 1 trauma center located in the Midwestern United States were retrospectively reviewed, and the injury mechanism and energy, time of injury, day of week, month, and patient characteristics (age, gender, comorbidities, smoking status) were collected. The fractures were classified using the AO (Arbeitsgemeinschaft für Osteosynthesefragen), Lauge-Hansen, and Danis-Weber systems. Of these systems, the Lauge-Hansen classification system resulted in the greatest number of "unclassifiable" cases. Most ankle fractures were due to high-energy mechanisms, with motor vehicle collisions the most common high-energy mechanism. The review found that most ankle fractures were malleolar fractures, regardless of the mechanism of injury. The ankle fracture patients had greater rates of obesity, diabetes, and smoking than present in the region where the hospital is located. The fractures were most likely to occur in the afternoon, with more fractures presenting on the weekend than earlier in the week and more fractures in the fall and winter than in the spring and summer. The temporal variation of these fractures should be considered for health services planning, in particular, in regard to resident physician staffing at urban level 1 trauma centers.

The New Surgical Technique for Improving Total Knee and Hip Arthroplasty Outcomes: Patient Selection.

BACKGROUND: Inclusion of patient satisfaction scores in setting reimbursements has been suggested by health care policy makers to contain cost and improve outcomes. The Short Form 36 Health Survey (SF-36) score provides a health-related quality of life (HRQoL) measure of arthroplasty outcome. Although previous work identified factors that influence this score for hip and knee arthroplasty patients, they did not focus on how a surgeon might use this information in a clinical setting. The present study examined whether relatively simple criteria might identify patients more likely to experience minimal HRQoL improvement. METHODS: "Improvements" in SF-36 composite physical scores and subscales were calculated from the difference between initial (preoperative) and SF-36 scores at 1 year. The rates of achieving a clinically significant improvement were compared between patient groups. RESULTS: After knee arthroplasty, women and younger patients achieved a clinically significant improvement in physical function more frequently than men and older patients (P = .04 and .02, respectively). The largest differences in improvement occurred between the diabetic and nondiabetic groups (P = .001), where the diabetic patients with ≥2 additional comorbidities demonstrated the lowest rate of achieving a clinically significant improvement in physical function and bodily pain. In comparison, in hip patients only age had significant influence on gains in physical function, but this did not alter the rate at which patients achieved a clinically significant improvement. CONCLUSION: These data indicate simple screening criteria can identify patients where arthroplasty might provide marginal HRQoL improvement. They suggest HRQoL-based reimbursement incentives will favor practices with younger, healthier patient populations.

Acute Disassembly and Dissociation of a Dual-Mobility Next-Generation Prosthesis.

The use of bipolar components in hip surgery was introduced more than 40 years ago with the rationale of a dual-mobility hip implant. This design used a small femoral head that would decrease the rate of wear because of the smaller surface area but would still provide implant stability because of the larger outer shell that articulated with the acetabulum, decreasing dislocation rates. In April 2011, the E1 Active Articulation Hip System (Biomet, Warsaw, Indiana) was introduced to the orthopedic market. It is considered to be part of the next generation of bipolar designs, with similar designs available from competing companies, such as Stryker (Mahwah, New Jersey). These designs merge the concept of an articulating outer shell with an all-polyethylene spacer with the primary articulation of a ceramic head and an outer polyethylene shell spacer. This case report describes disassembly and dissociation at the site of the primary articulation of a bipolar system that occurred between the ceramic femoral head and the outer all-polyethylene articulating shell in a patient who had revision total hip arthroplasty because of metallosis. The patient had a stable nonpainful metal-on-metal arthroplasty at first, immediately after the initial procedure. Although previous intraprosthetic dislocations (also called retentive failures) have occurred, this case has several unique features. [Orthopedics.2016; 39(5):e980-e983.].

Ankle fracture patterns in drivers are associated with femoral fracture, higher BMI, and advanced age.

OBJECTIVE: Despite advances in vehicle safety systems, motor vehicle crashes continue to cause ankle fractures. This study attempts to provide insight into the mechanisms of injury and to identify the at-risk population groups. METHODS: A study was made of ankle fractures patients treated at an urban level 1 trauma center following motor vehicle crashes, with a concurrent analysis of a nationally representative crash data set. The national data set focused on ankle fractures in drivers involved in frontal crashes. Statistical analysis was applied to the national data set to identify factors associated with fracture risk. RESULTS: Malleolar fractures occurred most frequently in the driver's right foot due to pedal interaction. The majority of complex/open fractures occurred in the left foot due to interaction with the vehicle floor. These fractures occurred in association with a femoral fracture, but their broad injury pattern suggests a range of fracture causation mechanisms. The statistical analysis indicated that the risk of fracture increased with increasing driver body mass index (BMI) and age. CONCLUSIONS: Efforts to reduce the risk of driver ankle injury should focus on right foot and pedal interaction. The range of injury patterns identified here suggest that efforts to minimize driver ankle fracture risk will likely need to consider injury tolerances for flexion, pronation/supination, and axial loading in order to capture the full range of injury mechanisms. In the clinical environment, physicians examining drivers after a frontal crash should consider those who are older or obese or who have severe femoral injury without concurrent head injury as highly suspicious for an ankle injury.

Nine year follow-up of a ceramic-on-ceramic bearing total hip arthroplasty utilizing a layered monoblock acetabular component.

INTRODUCTION: Early ceramic bearing systems in total hip arthoplasty (THA) sought to provide long term wear improvement over traditional metal on polyethylene systems. However, previous designs exhibited fractures of the ceramic acetabular liner, leading to the development of the Implex Hedrocel ceramic bearing THA system where the ceramic liner was supported on a layer of polyethylene intended to transition liner loads to the metal shell, a so-called "sandwich" design. Unfortunately, the device trial was stopped to further enrollment when liner fractures were reported. The current study examines nearly 10-year follow-up on 28 devices implanted by two surgeons at one institution in order to document ceramic bearing system performance over a longer time period. METHODS: Radiographic and patient reported outcomes, in the form of Harris Hip Scores (HHS) and 12-Item Short Form Health Survey (sF-12), were collected. RESULTS: During the study period two cups were replaced, one at three years and a second at seven years. At the five year follow-up HHS were similar to those reported in the literature for devices with traditional metal-on-polyethylene bearing surfaces and for other sandwich ceramic bearing designs. At the nine year follow-up, the HHS had not changed significantly and SF-12 scores measuring overall physical and mental health were higher than age matched national norms (p<0.001). There were no signs of cup migration, stem subsidence, osteolysis or cup loosening at any time up to the last follow-up in this patient cohort. The 89% survivorship rate and device revisions due to delamination of the liner observed in this group were similar to those reported earlier for this device and for other "sandwich design" ceramic bearing systems. DISCUSSION: This cohort did not exhibit new failure modes and HHS and SF-12 scores indicated high functionality for the majority of patients. These data suggest that a focus on preventing ceramic liner fracture through design and/or materials improvements may result in a device with long-term functionality.

Analysis of the basic science section of the orthopaedic in-training examination.

Since 1963, the Orthopaedic In-Training Examination (OITE) has been administered to orthopedic residents to assess residents' knowledge and measure the quality of teaching within individual programs. The OITE currently consists of 275 questions divided among 12 domains. This study analyzed all OITE basic science questions between 2006 and 2010. The following data were recorded: number of questions, question taxonomy, category of question, type of imaging modality, and recommended journal and book references. Between 2006 and 2010, the basic science section constituted 12.2% of the OITE. The assessment of taxonomy classification showed that recall-type questions were the most common, at 81.4%. Imaging modalities typically involved questions on radiographs and constituted 6.2% of the OITE basic science section. The majority of questions were basic science questions (eg, genetics, cell replication, and bone metabolism), with an average of 26.4 questions per year. The Journal of Bone & Joint Surgery (American Volume) and the American Academy of Orthopaedic Surgeons' Orthopaedic Basic Science were the most commonly and consistently cited journal and review book, respectively. This study provides the first review of the question content and recommended references of the OITE basic science section. This information will provide orthopedic trainees, orthopedic residency programs, and the American Academy of Orthopaedic Surgeons Evaluation Committee valuable information related to improving residents' knowledge and performance and optimizing basic science educational curricula.

Development of an interlocked nail for segmental defects in the rabbit tibia.

Previous animal models have been developed to study intramedullary nailing for challenging segmental defects in the tibia. In large animals, interlocked nail fixation created a stable environment suitable to study new bone growth technologies placed in the defect. To our knowledge, there are no comparable interlocked tibial defect models for the rabbit in which new technologies could be evaluated. Such a model would be helpful since the rabbit is a popular initial model for orthopedic research studies owing to its wide availability and low cost. While numerous studies have nailed the rabbit tibia, all were non-locked implants that allowed some degree of instability between the fracture fragments. In addition, the non-locked nails were constructed of stainless steel, whereas human nails are increasingly made from titanium alloy. In the current study, an interlocked titanium nail was developed for the rabbit tibia. It was implanted in cadaver tibiae and subjected to fatigue cycling in combined compression and bending at physiologic levels to 21,061 cycles. This duration is estimated to represent 12 weeks of gait by the animal. Before and after fatigue cycling, monotonic testing was performed in compression and bending at physiologic levels. The intact contralateral limbs served as controls. All limbs completed the cycling; the instrumented limbs exhibited interfragmentary cyclic strain amplitudes during fatigue (616 +/- 139 micro-strain), which was significantly greater than the control limbs (136 +/- 35 microstrain). Monotonic strain amplitudes for the test limbs in bending and compression were 4839 +/- 1028 and 542 +/- 122 microstrain, respectively; corresponding values for the control bones were 407 +/- 118 and 95 +/- 38 microstrain, respectively. These data are similar to those presented in prior studies in larger bone models. The current study presents one method for interlocked nail fixation for this complex tibial shaft fracture in a small animal.

Mycobacterium bovis infection of total hip arthroplasty after intravesicular bacille Calmette-Guérin therapy.

Bacille Calmette-Guérin (BCG) is a live, attenuated strain of Mycobacterium bovis. Intravesicular BCG therapy is the most effective treatment for superficial bladder cancer. The most common complication of this treatment is cystitis; there is a wide range of other complications. The English-language literature includes reports of 3 total hip arthroplasty infections and 1 total knee arthroplasty infection with M bovis after BCG therapy. These secondary infections may present either acutely during the therapy, months, or even years later. In this article, we report the case of a patient who presented with a painful right hip 6 years after successful total hip arthroplasty and 3 years after treatment for bladder cancer. Left total hip arthroplasty was performed 2 years after right hip arthroplasty. Surgeons examining a painful joint arthroplasty should be particularly suspicious of infection if the patient has a history of BCG therapy.

Streptococcus bovis infection of total hip arthroplasty in association with carcinoma of colon.

Streptococcus bovis is normally found in the gastrointestinal tract of the human population. The association between Streptococcus bovis and bowel neoplasia has been frequently reported. This report presents two cases of total hip arthroplasty with Streptococcus Bovis infection at 18 and 11 years after arthroplasty. The diagnosis was made with the help of clinical findings, standard radiographs, and laboratory tests (complete blood count, C-reactive protein, sedimentation rate, and the hip aspiration). Infections were treated by implant removal and antibiotic spacer implantation. Intravenous antibiotics were administered for 12 weeks. Revision arthroplasty was performed when laboratory tests (complete blood count, C-reactive protein, sedimentation rate) were within normal limits. Streptococcus bovis infection prompted the authors to investigate for any bowel malignancy. Colonoscopy and transrectal biopsy revealed adenocarcinoma in case 1, while case 2 had prior diagnosis of flat polyps in the colon. There are a limited number of reports in the literature reporting the presence of Streptococcus bovis infection concurrent with arthroplasty and bowel malignancy. These two case reports highlight the possibility of hematogenous seeding of arthroplasty components by Streptococcus bovis in patients with colonic neoplasia. Streptococcus bovis infection of hip arthroplasty may provide an opportunity for diagnosis of colonic neoplasia. Acute hip pain in patients with hip endoprostheses and simultaneous bowel malignancy should be evaluated promptly for hematogenous infection by standard radiograph, complete blood count, C-reactive protein, sedimentation rate, and hip aspiration.

Evaluation of transdermal steroids for trapeziometacarpal arthritis.

PURPOSE: One conservative treatment for trapeziometacarpal joint arthritis is the delivery of steroids transdermally. In prior transdermal studies on the elbow and foot, there are mixed reports of success. It appears that the benefits of the treatment might be limited to short-term relief (approximately one week). It was hypothesized that transdermal steroid delivery would yield short-term improvements for trapezial-metacarpal joint arthritis, although these improvements would not persist at later follow-up (3 or 6 months). METHODS: Eighty-four consecutive trapeziometacarpal joints in 62 patients presenting to an orthopedic hand surgeon were randomized to receive either steroid delivery by iontophoresis or phonophoresis or placebo delivery via iontophoresis or phonophoresis. The researchers and patients were blinded as to the treatment assignment. Patients were evaluated before treatment and at 3 follow-up appointments. Subjects were assessed via the Michigan Hand Outcomes Questionnaire, Short Form 12, analog pain score, and provocative and strength testing. The subjects' study group, gender, and arthritic grade were statistically analyzed versus patient-reported and physician-assessed data over the different time points. Following subject recruitment, 17 joints discontinued the study due to joint discomfort, electing for other treatments. Approximately half of the 67 subject joints opted for alternative treatment after the first or second follow-up; 34 subject joints completed all follow-up time points. RESULTS: There was no significant predictive relationship between the independent variables and their ability to predict the 9 dependent measures of pain, strength, and well-being. There were trends for the pain to decrease over time, although the trends were not uniform between the different pain metrics and groups. The strength for both iontophoresis groups tended to increase over time, whereas the phonophoresis groups tended to decline. CONCLUSIONS: Although there were some trends in the follow-up data, the overall lack of significant differences in the data suggests that transdermal steroid delivery might not be helpful in providing short- or long-term relief of arthritic symptoms. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic II.

Do scores of the USMLE Step 1 and OITE correlate with the ABOS Part I certifying examination?: a multicenter study.

BACKGROUND: The US Medical Licensing Examination (USMLE) and Orthopaedic In-Training Examination (OITE) are commonly used to select medical students or residents, respectively. Knowing how well these examinations predict performance on the American Board of Orthopaedic Surgery (ABOS) Part I certifying examination is important to provide evaluations for medical students and residents. Previous studies comparing the OITE scores with the ABOS Part 1 scores have been limited to one program. QUESTIONS/PURPOSES: Therefore, we compared the scores on the USMLE Step 1 and OITE examinations with those on the ABOS Part I certifying examination using data from four ACGME approved residency programs. METHODS: We reviewed 202 resident files from 1996 to 2008 from four programs in the same geographic region. Of those, 181 (90%) had complete records. De-identified data were used to compare USMLE Step 1 scores, OITE percentile rank scores, and ABOS Part I percentile rank scores. Pearson coefficients and receiver operator curves were calculated to assess the relationships between tests. RESULTS: We found a correlation of 0.53 between the USMLE Step 1 and ABOS Part I, and an average correlation of 0.50 for postgraduate years (PGY) 2 through 5 OITE scores and ABOS Part I. There was a stepwise increase in correlation from PGY 2 through PGY 5 between the OITE scores and ABOS scores. Those who averaged in the 27th percentile or lower on the OITE had a 57% chance of failing the ABOS Part I examination. CONCLUSION: USMLE Step 1 scores correlated with ABOS Part I certifying examination scores, and we therefore believe it may be used as one factor in resident selection. Use of the OITE scores in guiding education and feedback appears to be justified.

Casting technique and restraint choice influence child safety during transport of body casted children subjected to a simulated frontal MVA.

BACKGROUND: Hip spica casts (or body casts) are commonly applied to young pediatric trauma and hip dysplasia patients. The greatest hip stability in the cast is achieved via fixed hip flexion or abduction and fixed knee flexion. Unfortunately, this fixed position causes difficulties in restraining children for transport because the child cannot typically accommodate their body to the child car seat geometry. The objectives of the current study were to identify a range of reasonable seating options for casted children. These positions were then studied in frontal crash tests to identify the relative injury exposure for the different positions. A revised casting technique was also investigated in an effort to address head-to-cast contact identified during the course of the study. METHODS: The current study assessed the ability for different child seats and the vehicle seat belts to accommodate casted 1-year-old and 3-year-old crash test dummies. The restrained dummies were then subjected to frontal 30-mph crash tests with uncasted dummies serving as a control. RESULTS: In general, traditional child seats were able to accommodate both children; however, the child's body shifted anteriorly in the cast when the belts were tightened. This shift produced concerns for pulmonary function and the potential for elevated pressure on the superior mesenteric artery. This anterior shift of the chest was reduced when the dummies were restrained by a special hip spica child seat or solely by the vehicle seat belts. When considering all restraint types, the addition of the cast increased the majority of the injury metric magnitudes. For the 3-year-old dummy these increases were determined to be related to the casting technique; an alternative technique significantly reduced the injury metrics. CONCLUSIONS: This study demonstrates that there are anticipated variable effects on basic physiologic function for body-casted children based on the method of restraint. Restraint modalities which place the child forward facing with the face in proximity to the anterosuperior cast overlying the chest should be avoided.

The split-line pattern of the distal femur: A consideration in the orientation of autologous cartilage grafts.

PURPOSE: To identify the surface collagen orientations of the distal femur and create a generic cartilage split-line map that could be used as a reference guide for the proper alignment of autogenous cartilage transplants. TYPE OF STUDY: Anatomic, cadaveric study. METHODS: Eight fresh cadaveric knee joints were used to determine the collagen fiber orientation of the superficial layer of the articular cartilage of the distal femur. A split-line technique was used, in which a dissecting needle dipped in India ink was inserted into the cartilage. The resulting split between collagen fibers identified the preferential orientation of the collagen fibers at each needle insertion point. RESULTS: The results of the study show that a precise and consistent orientation of collagen fibers exists in areas that are known to experience significant joint load. CONCLUSIONS: Because the orientation of these split lines is thought to reflect the direction of tensile forces normally seen by the articular cartilage at a specific area, we hypothesize that proper orientation of autogenous cartilage plugs (with respect to split-line direction) may maximize resistance to these tensile forces and thus optimize the long-term health of these cartilage plugs.