In Vivo Assessment of Exercise-Induced Glenohumeral Cartilage Strain.

BACKGROUND: The human shoulder joint is the most mobile joint in the body. While in vivo shoulder kinematics under minimally loaded conditions have been studied, it is unclear how glenohumeral cartilage responds to high-demand loaded exercise. HYPOTHESIS: A high-demand upper extremity exercise, push-ups, will induce compressive strain in the glenohumeral articular cartilage, which can be measured with validated magnetic resonance imaging (MRI)-based techniques. STUDY DESIGN: Descriptive laboratory study. METHODS: High-resolution MRI was used to measure in vivo glenohumeral cartilage thickness before and after exercise among 8 study participants with no history of upper extremity injury or disease. Manual MRI segmentation and 3-dimensional modeling techniques were used to generate pre- and postexercise thickness maps of the humeral head and glenoid cartilage. Strain was calculated as the difference between pre- and postexercise cartilage thickness, normalized to the pre-exercise cartilage thickness. RESULTS: Significant compressive cartilage strains of 17% ± 6% and 15% ± 7% (mean ± 95% CI) were detected in the humeral head and glenoid cartilage, respectively. The anterior region of the glenoid cartilage experienced a significantly higher mean strain (19% ± 6%) than the posterior region of the glenoid cartilage (12% ± 8%). No significant regional differences in postexercise humeral head cartilage strain were observed. CONCLUSION: Push-ups induce compressive strain on the glenohumeral joint articular cartilage, particularly at the anterior glenoid. This MRI-based methodology can be applied to further the understanding of chondral changes in the shoulder under high-demand loading conditions. CLINICAL RELEVANCE: These results improve the understanding of healthy glenohumeral cartilage mechanics in response to loaded upper extremity exercise. In the future, these methods can be applied to identify which activities induce high glenohumeral cartilage strains and deviations from normal shoulder function.

The effects of femoral graft placement on cartilage thickness after anterior cruciate ligament reconstruction.

Altered joint motion has been thought to be a contributing factor in the long-term development of osteoarthritis after ACL reconstruction. While many studies have quantified knee kinematics after ACL injury and reconstruction, there is limited in vivo data characterizing the effects of altered knee motion on cartilage thickness distributions. Thus, the objective of this study was to compare cartilage thickness distributions in two groups of patients with ACL reconstruction: one group in which subjects received a non-anatomic reconstruction that resulted in abnormal joint motion and another group in which subjects received an anatomically placed graft that more closely restored normal knee motion. Ten patients with anatomic graft placement (mean follow-up: 20 months) and 12 patients with non-anatomic graft placement (mean follow-up: 18 months) were scanned using high-resolution MR imaging. These images were used to generate 3D mesh models of both knees of each patient. The operative and contralateral knee models were registered to each other and a grid sampling system was used to make site-specific comparisons of cartilage thickness. Patients in the non-anatomic graft placement group demonstrated a significant decrease in cartilage thickness along the medial intercondylar notch in the operative knee relative to the intact knee (8%). In the anatomic graft placement group, no significant changes were observed. These findings suggest that restoring normal knee motion after ACL injury may help to slow the progression of degeneration. Therefore, graft placement may have important implications on the development of osteoarthritis after ACL reconstruction.

Effects of intraarticular IL1-Ra for acute anterior cruciate ligament knee injury: a randomized controlled pilot trial (NCT00332254).

OBJECTIVE: To evaluate the clinical effectiveness of intraarticular IL-1 receptor antagonist (IL-1Ra) for anterior cruciate ligament (ACL) tear. METHODS: Eleven patients with acute ACL tear confirmed by magnetic resonance imaging (MRI) were randomized to receive a single intraarticular injection of IL-1Ra (anakinra 150 mg, n = 6) or equal volume of saline placebo (1 ml, n = 5). The double-blinded treatment was administered a mean 2 weeks after injury. Synovial fluid (SF) (n = 9 patients) and sera (all patients) were available at baseline (prior to injection) and immediately prior to surgery (mean 35 days later) and analyzed for SF IL-1α, IL-1ß, IL-1Ra and serum hyaluronan (HA), an indicator of synovial inflammation. The primary outcome, standardized Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire, was obtained at 0 (baseline), 4, and 14 days after injection. RESULTS: Compared with placebo, the IL-1Ra group had substantially greater improvement in key outcomes over 14 days (KOOS pain P = 0.001; activities of daily living P = 0.0015; KOOS sports function P = 0.0026; KOOS quality of life (QOL) P = 0.0048; and total KOOS P < 0.0001). There were no adverse reactions in either group. SF IL-1α (P = 0.05) and serum HA (P = 0.03), but not IL-1ß, or IL-1Ra, decreased significantly in the IL-1Ra but not the placebo treated patients. Compared with placebo, IL-1α was borderline significantly different in the IL-1Ra treated group (P = 0.06). CONCLUSIONS: Administered within the first month following severe knee injury, IL-1Ra reduced knee pain and improved function over a 2-week interval. This promising proof of concept study provides a new paradigm for studies of acute joint injury and suggests that a larger follow-up study is warranted.

The effects of femoral graft placement on in vivo knee kinematics after anterior cruciate ligament reconstruction.

Achieving anatomical graft placement remains a concern in Anterior Cruciate Ligament (ACL) reconstruction. The purpose of this study was to quantify the effect of femoral graft placement on the ability of ACL reconstruction to restore normal knee kinematics under in vivo loading conditions. Two different groups of patients were studied: one in which the femoral tunnel was placed near the anterior and proximal border of the ACL (anteroproximal group, n=12) and another where the femoral tunnel was placed near the center of the ACL (anatomic group, n=10) MR imaging and biplanar fluoroscopy were used to measure in vivo kinematics in these patients during a quasi-static lunge. Patients with anteroproximal graft placement had up to 3.4mm more anterior tibial translation, 1.1mm more medial tibial translation and 3.7° more internal tibial rotation compared to the contralateral side. Patients with anatomic graft placement had motion that more closely replicated that of the intact knee, with anterior tibial translation within 0.8mm, medial tibial translation within 0.5mm, and internal tibial rotation within 1°. Grafts placed anteroproximally on the femur likely provide insufficient restraint to these motions due to a more vertical orientation. Anatomical femoral placement of the graft is more likely to reproduce normal ACL orientation, resulting in a more stable knee. Therefore, achieving anatomical graft placement on the femur is crucial to restoring normal knee function and may decrease the rates of joint degeneration after ACL reconstruction.

Biomechanical evaluation of two reconstruction techniques for posterolateral instability of the knee.

We evaluated two reconstruction techniques for a simulated posterolateral corner injury on ten pairs of cadaver knees. Specimens were mounted at 30° and 90° of knee flexion to record external rotation and varus movement. Instability was created by transversely sectioning the lateral collateral ligament at its midpoint and the popliteus tendon was released at the lateral femoral condyle. The left knee was randomly assigned for reconstruction using either a combined or fibula-based treatment with the right knee receiving the other. After sectioning, laxity increased in all the specimens. Each technique restored external rotatory and varus stability at both flexion angles to levels similar to the intact condition. For the fibula-based reconstruction method, varus laxity at 30° of knee flexion did not differ from the intact state, but was significantly less than after the combined method. Both the fibula-based and combined posterolateral reconstruction techniques are equally effective in restoring stability following the simulated injury.

Femoral tunnel placement during anterior cruciate ligament reconstruction: an in vivo imaging analysis comparing transtibial and 2-incision tibial tunnel-independent techniques.

BACKGROUND: Recent studies have questioned the ability of the transtibial technique to place the anterior cruciate ligament graft within the footprint of the anterior cruciate ligament on the femur. There are limited data directly comparing the abilities of transtibial and tibial tunnel-independent techniques to place the graft anatomically at the femoral attachment site of the anterior cruciate ligament in patients. HYPOTHESIS: Because placement with the tibial tunnel-independent technique is unconstrained by the tibial tunnel, it would allow for more anatomic tunnel placement compared with the transtibial technique. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: High-resolution, multiplanar magnetic resonance imaging and advanced 3-dimensional modeling techniques were used to measure in vivo femoral tunnel placement in 8 patients with the transtibial technique and 8 patients with a tibial tunnel-independent technique. Femoral tunnel placement in 3 dimensions was measured relative to the center of the native anterior cruciate ligament attachment on the intact contralateral knee. RESULTS: The tibial tunnel-independent technique placed the graft closer to the center of the native anterior cruciate ligament attachment compared with the transtibial technique. The transtibial technique placed the tunnel center an average of 9 mm from the center of the anterior cruciate ligament attachment, compared with 3 mm for the tibial tunnel-independent technique. The transtibial technique resulted in a more anterior and superior placement of the tunnel compared with the tibial tunnel- independent technique. CONCLUSION: The tibial tunnel-independent technique allowed for more anatomic femoral tunnel placement compared with the transtibial technique.

Continental variations in preoperative and postoperative management of patients with anterior cruciate ligament repair.

AIM: Surgeon decision making for non-operative anterior cruciate ligament (ACL) treatment and postoperative rehabilitation is influenced by a myriad of factors. The aim of this study was to investigate intercontinental differences in surgeon decision making for care of the ACL deficient patient. The authors hypothesized that significant variation in clinical decision of ACL deficient patients existed among surgeons in different continents. METHODS: This study involved a survey design, which met the checklist for reporting results of internet e-surveys (CHERRIES) guidelines. The survey was administered to orthopedic surgeons in 15 countries and involved standardized follow up and design. Questions related to non-operative care management and postoperative/rehabilitative management were provided to each respondent. Statistical analyses included multivariate comparisons among continents and regression findings for likelihood of targeting longer term non-operative treatment. RESULTS: Over six hundred (634) surgeons completed the survey, representing six continents. Continental variations were found in non-operative surgical decision making and postoperative/rehabilitative management. Significant differences were noted in nearly all clinical decision making categories. CONCLUSION: Variations do exist across continents in the non-operative and postoperative/rehabilitative management of patients with an ACL tear. Continental variations and disparate emphases such as activity level, age during injury, and bracing influenced treatment decision making, which could lead to variations in outcomes, costs, and appropriate care.

A comparison of cleat types during two football-specific tasks on FieldTurf.

OBJECTIVE: To examine the effect of different cleat plate configurations on plantar pressure during two tasks. DESIGN: Thirty-six athletes ran an agility course 5 times while wearing 4 different types of Nike Vitoria cleats: (1) bladed, (2) elliptical firm ground, (3) hard ground and (4) turf. Plantar pressure data were recorded during a side cut and a cross cut using Pedar-X insoles. SETTING: Controlled laboratory study PARTICIPANTS: No history of lower extremity injury in the past 6 months, no previous foot or ankle surgery, not currently wearing foot orthotics and play a cleated sport at least twice a week. MAIN OUTCOME MEASUREMENTS: Total foot contact time, contact area, maximum force, peak pressure and the force-time integral (FTI) in the medial, middle and lateral regions of the forefoot were collected. A 1x4 ANOVA (alpha = 0.05) was performed on each dependent variable. A Bonferroni adjustment was conducted (alpha = 0.008). RESULTS: In the cross cut task, statistical differences between cleats were observed in three variables: total foot peak pressure, lateral forefoot FTI, and lateral forefoot normalised maximum force. In the side cut task, statistical differences between cleats were observed in 4 variables: total foot peak pressure, the medial and middle forefoot FTI, and the medial and middle forefoot normalised maximum force. CONCLUSIONS: Significant differences in forefoot loading patterns existed between cleat types. Based on the results of this study, it might be beneficial to increase the forefoot cushioning in cleats in an attempt to decrease loading in these regions of the foot.

Physical examination tests of the shoulder: a systematic review with meta-analysis of individual tests.

OBJECTIVE: To compile and critique research on the diagnostic accuracy of individual orthopaedic physical examination tests in a manner that would allow clinicians to judge whether these tests are valuable to their practice. METHODS: A computer-assisted literature search of MEDLINE, CINAHL, and SPORTDiscus databases (1966 to October 2006) using keywords related to diagnostic accuracy of physical examination tests of the shoulder. The Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool was used to critique the quality of each paper. Meta-analysis through meta-regression of the diagnostic odds ratio (DOR) was performed on the Neer test for impingement, the Hawkins-Kennedy test for impingement, and the Speed test for superior labral pathology. RESULTS: Forty-five studies were critiqued with only half demonstrating acceptable high quality and only two having adequate sample size. For impingement, the meta-analysis revealed that the pooled sensitivity and specificity for the Neer test was 79% and 53%, respectively, and for the Hawkins-Kennedy test was 79% and 59%, respectively. For superior labral (SLAP) tears, the summary sensitivity and specificity of the Speed test was 32% and 61%, respectively. Regarding orthopaedic special tests (OSTs) where meta-analysis was not possible either due to lack of sufficient studies or heterogeneity between studies, the list that demonstrates both high sensitivity and high specificity is short: hornblowers's sign and the external rotation lag sign for tears of the rotator cuff, biceps load II for superior labral anterior to posterior (SLAP) lesions, and apprehension, relocation and anterior release for anterior instability. Even these tests have been under-studied or are from lower quality studies or both. No tests for impingement or acromioclavicular (AC) joint pathology demonstrated significant diagnostic accuracy. CONCLUSION: Based on pooled data, the diagnostic accuracy of the Neer test for impingement, the Hawkins-Kennedy test for impingement and the Speed test for labral pathology is limited. There is a great need for large, prospective, well-designed studies that examine the diagnostic accuracy of the numerous physical examination tests of the shoulder. Currently, almost without exception, there is a lack of clarity with regard to whether common OSTs used in clinical examination are useful in differentially diagnosing pathologies of the shoulder.

Duke Surgery Research Central: an open-source Web application for the improvement of compliance with research regulation.

BACKGROUND: Although regulatory compliance in academic research is enforced by law to ensure high quality and safety to participants, its implementation is frequently hindered by cost and logistical barriers. In order to decrease these barriers, we have developed a Web-based application, Duke Surgery Research Central (DSRC), to monitor and streamline the regulatory research process. RESULTS: The main objective of DSRC is to streamline regulatory research processes. The application was built using a combination of paper prototyping for system requirements and Java as the primary language for the application, in conjunction with the Model-View-Controller design model. The researcher interface was designed for simplicity so that it could be used by individuals with different computer literacy levels. Analogously, the administrator interface was designed with functionality as its primary goal. DSRC facilitates the exchange of regulatory documents between researchers and research administrators, allowing for tasks to be tracked and documents to be stored in a Web environment accessible from an Intranet. Usability was evaluated using formal usability tests and field observations. Formal usability results demonstrated that DSRC presented good speed, was easy to learn and use, had a functionality that was easily understandable, and a navigation that was intuitive. Additional features implemented upon request by initial users included: extensive variable categorization (in contrast with data capture using free text), searching capabilities to improve how research administrators could search an extensive number of researcher names, warning messages before critical tasks were performed (such as deleting a task), and confirmatory e-mails for critical tasks (such as completing a regulatory task). CONCLUSION: The current version of DSRC was shown to have excellent overall usability properties in handling research regulatory issues. It is hoped that its release as an open-source application will promote improved and streamlined regulatory processes for individual academic centers as well as larger research networks.

A randomised controlled feasibility trial of vitrectomy versus laser for diabetic macular oedema.

AIM: (1) To evaluate whether vitrectomy is preferable to further macular laser in improving visual acuity and resolving retinal thickening in patients with diabetic macular oedema (DMO) despite previous laser and no macular traction. (2) To determine the feasibility of further trials in this population in terms of magnitude of comparative clinical effect, rate of recruitment, and loss to follow up. METHODS: A randomised controlled feasibility study. Patients with DMO and a visual acuity of 0.3 logMAR (6/12) or worse after one or more macular laser treatments were randomised on a 1:1 basis to either pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling or further macular laser. Patients with a posterior vitreous detachment, biomicroscopic evidence of retinal traction, or a taut thickened posterior hyaloid (TTPH) were excluded. Primary outcome measures were (1) best corrected logMAR visual acuity, (2) mean central macular thickness on optical coherence tomography, and (3) rate of recruitment and loss to follow up. Analysis was on an intention to treat basis. RESULTS: 19 patients were randomised to PPV and 21 to further macular laser. The mean baseline logMAR visual acuity was 0.65 (SD 0.28) for the group randomised to PPV and 0.60 (0.23) for the group randomised to laser. The mean change in best corrected visual acuity of the vitrectomy group was deterioration by 0.05 logMAR, while in the control group the mean change was an improvement of 0.03 logMAR. The median (interquartile range) baseline central macular thickness was 403 (337, 492) for the group randomised to PPV and 387 (298, 491) for the controls randomised to laser. The median change in central macular thickness from baseline to review in the vitrectomy group was a thinning by 73 mum (20%) and by 29 mum (10.7%) in the control laser group. This single centre was able to recruit 40 patients in 18 months with follow up of 82% at 1 year. CONCLUSION: A randomised controlled trial was found to be potentially feasible in this population, the rate of recruitment was however slow and one in five patients were lost to follow up because of death and ill health. These data provide little evidence in terms of visual acuity and macular thickness of any benefit of vitrectomy over further macular laser in patients with an attached hyaloid, DMO despite previous laser, and no clinically evident macular traction or TTPH.

The assessment of athletic hip injury.

The differential diagnosis of athletic hip pain is extensive. The physical demands of sport place the athlete at increased risk to injure the hip. The basis of successful treatment of the athlete with hip pain lies in the ability of the physician to assess and diagnose the etiology accurately. A thorough understanding of the evaluation of the athlete with hip pain allows for an earlier diagnosis, earlier treatment, and ultimately an earlier return to sport.

Effects of technique variations on knee biomechanics during the squat and leg press.

PURPOSE: The specific aim of this project was to quantify knee forces and muscle activity while performing squat and leg press exercises with technique variations. METHODS: Ten experienced male lifters performed the squat, a high foot placement leg press (LPH), and a low foot placement leg press (LPL) employing a wide stance (WS), narrow stance (NS), and two foot angle positions (feet straight and feet turned out 30 degrees ). RESULTS: No differences were found in muscle activity or knee forces between foot angle variations. The squat generated greater quadriceps and hamstrings activity than the LPH and LPL, the WS-LPH generated greater hamstrings activity than the NS-LPH, whereas the NS squat produced greater gastrocnemius activity than the WS squat. No ACL forces were produced for any exercise variation. Tibiofemoral (TF) compressive forces, PCL tensile forces, and patellofemoral (PF) compressive forces were generally greater in the squat than the LPH and LPL, and there were no differences in knee forces between the LPH and LPL. For all exercises, the WS generated greater PCL tensile forces than the NS, the NS produced greater TF and PF compressive forces than the WS during the LPH and LPL, whereas the WS generated greater TF and PF compressive forces than the NS during the squat. For all exercises, muscle activity and knee forces were generally greater in the knee extending phase than the knee flexing phase. CONCLUSIONS: The greater muscle activity and knee forces in the squat compared with the LPL and LPH implies the squat may be more effective in muscle development but should be used cautiously in those with PCL and PF disorders, especially at greater knee flexion angles. Because all forces increased with knee flexion, training within the functional 0-50 degrees range may be efficacious for those whose goal is to minimize knee forces. The lack of ACL forces implies that all exercises may be effective during ACL rehabilitation.

Ligamentous restraints of the second tarsometatarsal joint: a biomechanical evaluation.

Ligamentous injury of the tarsometatarsal joint complex is an uncommon, but disabling condition that frequently occurs in elite athletes. There are few options for managing these injuries, in part because the relative mechanical contribution of the ligaments of the tarsometatarsal joint is unknown, complicating decisions regarding which ligaments need reconstruction. In the current study, strength and stiffness of the dorsal, plantar, and Lisfranc ligaments of 20 paired cadaver feet were measured and compared. The plantar and Lisfranc ligaments were significantly stiffer and stronger than the dorsal ligament, and the Lisfranc ligament was significantly stronger and stiffer than the plantar ligament.

Role of the Escherichia coli nucleotide excision repair proteins in DNA replication.

DNA polymerase I (PolI) functions both in nucleotide excision repair (NER) and in the processing of Okazaki fragments that are generated on the lagging strand during DNA replication. Escherichia coli cells completely lacking the PolI enzyme are viable as long as they are grown on minimal medium. Here we show that viability is fully dependent on the presence of functional UvrA, UvrB, and UvrD (helicase II) proteins but does not require UvrC. In contrast, delta polA cells grow even better when the uvrC gene has been deleted. Apparently UvrA, UvrB, and UvrD are needed in a replication backup system that replaces the PolI function, and UvrC interferes with this alternative replication pathway. With specific mutants of UvrC we could show that the inhibitory effect of this protein is related to its catalytic activity that on damaged DNA is responsible for the 3' incision reaction. Specific mutants of UvrA and UvrB were also studied for their capacity to support the PolI-independent replication. Deletion of the UvrC-binding domain of UvrB resulted in a phenotype similar to that caused by deletion of the uvrC gene, showing that the inhibitory incision activity of UvrC is mediated via binding to UvrB. A mutation in the N-terminal zinc finger domain of UvrA does not affect NER in vivo or in vitro. The same mutation, however, does give inviability in combination with the delta polA mutation. Apparently the N-terminal zinc-binding domain of UvrA has specifically evolved for a function outside DNA repair. A model for the function of the UvrA, UvrB, and UvrD proteins in the alternative replication pathway is discussed.

Intramuscular corticosteroid injection for hamstring injuries. A 13-year experience in the National Football League.

The purpose of this study was to assess the safety of intramuscular corticosteroid injection in selected, severe hamstring injuries in professional football players. Clinicians have been reluctant to use corticosteroid injections in or around muscle-tendon units because of concern of incomplete healing or rupture. We retrospectively reviewed the computer database of one National Football League team for all hamstring injuries requiring treatment between January 1985 and January 1998. We found that 431 players had suffered such injury. We developed a clinical grading system to identify hamstring injury severity and to stratify players for treatment. Fifty-eight players (13%) sustained severe, discrete injuries with a palpable defect within the substance of the muscle and were treated with intramuscular injection of corticosteroid and anesthetic. There were no complications related to the injection of corticosteroid. Only nine players (16%) missed any games as a result of their injury. Final examination revealed no strength deficits, normal muscle bulk and tone, and the ability to generate normal power. We believe that the grading system we developed can assist in selection of injury type for injection. Although lack of a control group limits statements of efficacy of injection, our impression is that intramuscular corticosteroid injection hastens players' return to full play and lessens the game and practice time they miss.

The early effect of ibuprofen on the mechanical properties of healing medial collateral ligament.

We tested the hypothesis that injured ligaments in rabbits treated with ibuprofen would have decreased values of mechanical properties compared with the values of those treated with a placebo. In 24 New Zealand White rabbits, the medial collateral ligament of one hindlimb was ruptured; the contralateral ligament served as an internal control. The rabbits were treated orally, twice daily, with a 14-day course of either 35 mg of ibuprofen per kilogram of body weight or a placebo. The rabbits were sacrificed at 14 or 28 days, and the ligaments were tested in tension to failure at 0.15 mm/sec. There was no statistically significant difference in the values of mechanical properties of ligaments from rabbits treated with ibuprofen versus those treated with placebo at either 14 or 28 days after injury. Our findings suggest that there is no early deleterious effect of a short course of ibuprofen on the mechanical behavior of medial collateral ligaments.