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INTRODUCTION Hand-tying surgical knots is an important skill that is applicable across all surgical disciplines. Knot quality is traditionally assessed in the operating room by visual inspection, which is inherently subjective. With the increasing prevalence of simulation training, surgical trainees having access to objective feedback of their knot-tying skills are paramount for skill evaluation. Our study aimed to validate a mechanical suture loop security tester as an objective evaluation method of hand-tied surgical knot quality. METHODS Seventy-three subjects were recruited and categorized based on surgical expertise into one of the following three groups: medical students, surgical residents, and attending surgeons. They hand-tied five surgical knots consecutively using 0 Vicryl sutures. The knots were tested using the suture loop security workstation with 10 lbs of linear force for 10 seconds. Success of the suture loop was set at less than 3 mm of loop expansion. This protocol was based on previous research showing that 3 mm of loop expansion would represent clinical failure of the knot in vivo. RESULTS The students, residents, and attending surgeons tied a median of two, three, and four successful knots, respectively. Post hoc pairwise comparisons revealed that residents tied more successful knots than students (p < 0.001), and attending physicians tied more successful knots than students (p < 0.001). However, there was no statistically significant difference in the number of successes between residents and attending physicians (p = 0.24). CONCLUSIONS Using the mechanical loop security workstation demonstrates construct validity as a reliable objective evaluation tool of hand-tied surgical knots.

INTRODUCTION In a prior study, we validated the FAST workstation as an objective evaluator of hand-tied surgical knots. The goal of this study was to determine whether guided practice with the FAST workstation could lead to objective improvement in hand-tied surgical knot performance. METHODS Sixty participants were randomized into 1 of 2 groups: a control group, with access to only the knot-tying station, and a test group, with access to the knot-tying station plus the knot testing station. The study was divided into 3 phases: prepractice, practice, and postpractice. Using the FAST workstation, participants hand-tied 5 knots, 15 knots, and 5 knots using 0 Vicryl suture in the prepractice, practice, and postpractice phases, respectively. Knots for each participant from the prepractice and postpractice phases were collected, tested, and compared. RESULTS Within the control group, the average number of prepractice knot successes was 2.63, and the average number of postpractice knot successes was 3.40, which resulted in an improvement of average knot successes of 0.77 (P < 0.01). Within the test group, the average number of prepractice knot successes was 2.40, and the average number of postpractice knot successes was 4.10, which resulted in an improvement of average knot successes of 1.70 (P < 0.01). The difference in average improvement of knot-tying successes (0.93 knots) between the 2 groups was statistically significant (P < 0.01). DISCUSSION A knot-tying trainer that provides objective feedback on knot performance may better improve hand-tied surgical knot proficiency compared with one without objective feedback.

To determine the inter-rater reliability (IRR) of a procedure-specific checklist scored in a binary fashion for the evaluation of surgical skill and whether it meets a minimum level of agreement (≥0.8 between 2 raters) required for high-stakes assessment.In a prospective randomized and blinded fashion, and after detailed assessment training, 10 Arthroscopy Association of North America Master/Associate Master faculty arthroscopic surgeons (in 5 pairs) with an average of 21 years of surgical experience assessed the video-recorded 3-anchor arthroscopic Bankart repair performance of 44 postgraduate year 4 or 5 residents from 21 Accreditation Council for Graduate Medical Education orthopaedic residency training programs from across the United States.No paired scores of resident surgeon performance evaluated by the 5 teams of faculty assessors dropped below the 0.8 IRR level (mean = 0.93; range 0.84-0.99; standard deviation = 0.035). A comparison between the 5 assessor groups with 1 factor analysis of variance showed that there was no significant difference between the groups (P = .205). Pearson's product-moment correlation coefficient revealed a strong and statistically significant negative correlation, that is, -0.856 (P.000), indicating that as intra-operative error rate scores increased, the IRR decreased.Arthroscopy Association of North America shoulder faculty raters from across the United States showed high levels of IRR in the assessment of an arthroscopic 3-anchor Bankart repair procedure. All paired assessments were above the 0.8 level and the mean IRR of all resident assessments was 0.93, indicating that they could be used for high-stakes decisions.With the move toward outcomes-based performance evaluation for graduate medical education, high-stakes assessments of surgical skill will require robust, reliable measurement tools that are able to withstand challenge. Surgical checklists employing metrics scored in a binary fashion meet the need and can show a high (80%) IRR.

This in vitro study evaluated the biomechanical benefit of adding spanning sutures to single-row rotator cuff repair.Mechanical testing was performed to evaluate 9 pairs of cadaveric shoulders with complete rotator cuff repairs, with a single-row technique used on one side and the suture spanning technique on the other. The spanning technique included sutures from 2 lateral anchors securing tendon near the musculotendinous junction, spanning the same anchor placement from single-row repair. The supraspinatus muscle was loaded to 100 N at 0.25 Hz for 100 cycles, followed by a ramp to failure. Markers and a video tracking system measured anterior and posterior gap formation across the repair at 25-cycle intervals. The force at which the stiffness decreased by 50% and 75% was determined. Data were compared using paired t-tests.One single-row repair failed at25 cycles. Both anterior and posterior gap distances tended to be 1 to 2 mm larger for the single-row repairs than for the suture spanning technique. The difference was statistically significant at all cycles for the posterior gap formation (P ≤ .02). The trends were not significant for the anterior gap (P ≥ .13). The loads at which the stiffness decreased by 50% and 75% did not differ significantly between the 2 types of repair (P ≥ .10).The suture spanning technique primarily improved posterior gap formation. Decreased posterior gap formation could reduce failure rates for rotator cuff repair.

Wearable inertial sensors can be used for assessment of surgeon body motion during arthroscopy, with demonstrated macroergonomic differences observed between novices and experts during diagnostic arthroscopy of a right cadaver knee. Before the adoption of arthroscopy training benchmarks based on inertial sensor technology, validation research should cross-correlate ergonomic variables with surgical quality.

Bench-top arthroscopy training requires some form of camera visualization. Use of clinical arthroscopy equipment in a virtual reality simulation lab may be cost prohibitive for some training programs. There are creative ways to build homemade, inexpensive camera setups for basic arthroscopy skills training.

Arthroscopic knot tying remains challenging, and the knots are a weak link for many repair constructs. Knotless strategies continue to evolve, and in some cases, these methods enhance biomechanical repair characteristics. The associated impact on clinical outcomes remains unknown.

Purpose: To determine if previously validated performance metrics for an arthroscopic Bankart repair (ABR) coupled with a cadaveric shoulder are a valid assessment tool with the ability to discriminate between the performances of experienced and novice surgeons and to establish a proficiency benchmark for an ABR using a cadaveric shoulder. Methods: Ten master/associate master faculty from an Arthroscopy Association of North America Resident Course (experienced group) were compared with 12 postgraduate year 4 and postgraduate year 5 orthopaedic residents (novice group). Each group was instructed to perform a diagnostic arthroscopy and a 3 suture anchor Bankart repair on a cadaveric shoulder. The procedure was videotaped in its entirety and independently scored in blinded fashion by a pair of trained reviewers. Scoring was based on defined and previously validated metrics for an ABR and included steps, errors, “sentinel” (more serious) errors, and time. Results: The inter-rater reliability was 0.92. Novice surgeons made 50% more errors (5.86 v 2.95, P ¼ .013), showed more performance variability (SD, 1.86 v 0.55), and took longer to perform the procedure (45.5 minutes v 25.9 minutes, P < .001). The greatest difference in errors related to suture delivery and management (exclusive of knot tying) (1.95 v 0.45, P ¼ .024). Conclusions: The assessment tool composed of validated arthroscopic Bankart metrics coupled with a cadaveric shoulder accurately distinguishes the performance of experienced from novice orthopaedic surgeons. A benchmark based on the mean performance of the experienced group includes completion of a 3-anchor Bankart repair, and enacting no more than 3 total errors and 1 sentinel error. Clinical Relevance: Validated procedural metrics combined with the use of a cadaveric shoulder can be used to assess the performance of an ABR. The methodology used may serve as a template for outcomes-based procedural skills training in general.

Purpose To determine if a dry shoulder model simulator coupled with previously validated performance metrics for an arthroscopic Bankart repair (ABR) would be a valid tool with the ability to discriminate between the performance of experienced and novice surgeons, and to establish a proficiency benchmark for an ABR using a model simulator. Methods We compared an experienced group of arthroscopic shoulder surgeons (Arthroscopy Association of North America faculty) (n = 12) with a novice group (n = 7) (postgraduate year 4 or 5 orthopaedic residents). All surgeons were instructed to perform a diagnostic arthroscopy and a 3 suture anchor Bankart repair on a dry shoulder model. Each procedure was videotaped in its entirety and scored in blinded fashion independently by 2 trained reviewers. Scoring used previously validated metrics for an ABR and included steps, errors, and "sentinel" (more serious) errors. Results The inter-rater reliability among pairs of raters averaged 0.93. The experienced group made 63% fewer errors, committed 79% fewer sentinel errors, and performed the procedure in 42% less time than the novice group (all significant differences). The greatest difference in errors between the groups involved anchor preparation and insertion, suture delivery and management, and knot tying. Conclusions The tool comprised by validated ABR metrics coupled with a dry shoulder model simulator is able to accurately distinguish between the performance of experienced and novice orthopaedic surgeons. A performance benchmark based on the mean performance of the experienced group includes completion of a 3 anchor Bankart repair, enacting no more than 4 total errors and 1 sentinel error. Clinical Relevance The combination of performance metrics and an arthroscopic shoulder model simulator can be used to improve the effectiveness of surgical skills training for an ABR. The methodology used may serve as a template for outcomes-based procedural skills training in general.

Simulation-based surgical skills training has become essential in orthopaedic practice because of concerns about patient safety and an increase in technically challenging procedures. Surgical skills training in specifically designed simulation laboratories allows practice of procedures in a risk-free environment before they are performed in the operating room. The transferability of acquired skills to performance with patients is the most effective measure of the predictive validity of simulation-based training. Retention of the skills transferred to clinical situations is also critical. However, evidence of simulation-based skill retention in the orthopaedic literature is limited, and concerns about sustainability exist. Solutions for skill decay include repeated practice of the tasks learned on simulators and reinforcement of areas that are sensitive to decline. Further research is required to determine the retention rates of surgical skills acquired in simulation-based training as well as the success of proposed solutions for skill decay.

Arthroscopic knot tying is a challenging motor skill that is best learned at the benchtop, before surgery on patients. Recent studies suggest that these skills can be improved by direct assessment of knot biomechanics, providing the learner with immediate and objective feedback. To optimize proficiency at arthroscopic knot tying, we focus on performance over appearance.

Background The American College of Surgeons-Accredited Education Institutes (ACS-AEI) Consortium aims to enhance patient safety and advance surgical education through the use of cutting-edge simulation-based training and assessment methods. The annual ACS-AEI Consortium meeting provides a forum to discuss the latest simulation-based training and assessment methods and includes special panel presentations on key topics. Methods During the 8th annual Consortium, there was a panel presentation on simulation-based summative assessments, during which experiences from across surgical disciplines were presented. The formal presentations were followed by a robust discussion between the conference attendees and the panelists. Results This report summarizes the panelists' presentations and their ensuing discussion with attendees. Conclusion The focus of this report is on the basis for and advances in simulation-based summative assessments, the current practices employed across various surgical disciplines, and future directions that may be pursued by the ACS-AEI Consortium.

We report the use of a 15° face-changing cementless acetabular component in patients undergoing total hip replacement for osteoarthritis secondary to developmental dysplasia of the hip. The rationale behind its design and the surgical technique used for its implantation are described. It is distinctly different from a standard cementless hemispherical component as it is designed to position the bearing surface at the optimal angle of inclination, that is, < 45°, while maximising the cover of the component by host bone.

Tibial-side fixation of soft-tissue grafts in osteoporotic bone has become an important concern, as anterior cruciate ligament reconstruction indications push toward older patients. Although soft-tissue fixation with an interference screw and cortical button may be statistically stronger than graft fixation with a screw or button alone, this hybrid construct is probably not optimized from a clinical perspective.

The "50% rule" is used commonly to guide treatment of partial tears of tendons and ligaments. The purpose of this study was to examine the history and validity of the 50% rule in arthroscopic and orthopaedic surgery. A PubMed search yielded 1,039 articles that were reviewed to identify the origins of the 50% rule for hand flexor tendon lacerations, partial anterior cruciate ligament tears, partial-thickness rotator cuff tears, and partial injuries of the long head of the biceps tendon. The rule appears to have evolved from the hand literature toward somewhat arbitrary application for other orthopaedic conditions. Little scientific information is available to support the 50% rule for these disparate entities. In our Level V opinion, the 50% rule allows surgeons to use subjective discretion in the management of prevalent orthopaedic conditions but there is very little scientific support for this ubiquitous decision-making criterion.

Of the 31 recommendations made by the work group, 19 were determined to be inconclusive because of the absence of definitive evidence. Of the remaining recommendations, four were classified as moderate grade, six as weak, and two as consensus statements of expert opinion. The four moderate-grade recommendations include suggestions that exercise and nonsteroidal anti-inflammatory drugs be used to manage rotator cuff symptoms in the absence of a full-thickness tear, that routine acromioplasty is not required at the time of rotator cuff repair, that non-cross-linked, porcine small intestine submucosal xenograft patches not be used to manage rotator cuff tears, and that surgeons can advise patients that workers' compensation status correlates with less favorable outcomes after rotator cuff surgery.

Our purpose was to investigate the importance of medial-row knot tying to mechanical stability in a double-row rotator cuff repair by comparing a knotless construct with transtendon anchor passage versus a similar construct implementing medial knots.A standard defect was created in the infraspinatus tendons of 14 bovine humeri. All defects were repaired with 2 medial and 2 lateral anchors (SutureCross System; KFx Medical, Carlsbad, CA). The medial anchors were either placed by transtendon passage in a knotless construct or placed directly into bone with needle passage of suture to create bursal-sided knots medially. Constructs were subjected to a cyclic loading protocol and then loaded to failure.The medially knotted constructs had a statistically higher stiffness at both the initial and final cycles (P.001 and P.001, respectively) and a lower displacement during cyclic loading (P.02). There were strong trends toward decreased gauge displacement (P = .12) and decreased cycles to 3 mm of displacement (P = .07) in the medially knotted group. Maximal yield strength was greater in the medially knotted group (350 +/- 270 N v 650 +/- 530 N), although this was not found to be statistically significant (P = .5).Our data suggest that creation of medial knots increases construct stiffness and stability in arthroscopic double-row cuff repair. This is likely because of increased load transfer to the lateral anchor and suture-tendon interface in the knotless construct.Medial knots create increased mechanical stability that theoretically may improve rotator cuff healing. This mechanical advantage must be weighed against surgical efficiency, with consideration given to factors such as tissue quality.

Summary The paper is a case study of an 81-year-old female with an acute onset of idiopathic thrombocytopenic purpura (ITP). This diagnosis is rare in adults, and this article discusses the patient's clinical presentation and a review of ITP.

The diagnosis and management of an active patient with biceps disease can be challenging for the treating physician. A careful review of the function, anatomy, and pathology of biceps in conjunction with a thorough, knowledgeable history and physical examination can yield a working diagnosis in this challenging patient population. The physician must also be aware of the physiology of postsurgical repair and advocate appropriate rehabilitation activities that correlate with the timeline of secure tissue healing. This article focuses on nonsurgical rehabilitation and postoperative rehabilitation of biceps tendon injuries.

Introduction Simulation-based training is playing an increasingly important role in surgery. However, there is insufficient discussion among the surgical specialties regarding how simulation may best be leveraged for training. There is much to be learned from one another as we all strive to meet new requirements within the context of Undergraduate Medical Education, Graduate Medical Education, and Continuing Medical Education. Method To address this need, a panel was convened at the 6th Annual Meeting of the Consortium of the American College of Surgeons-Accredited Education Institutes consisting of key leaders in the field of simulation from 4 surgical subspecialties, namely, general surgery, orthopedic surgery, cardiothoracic surgery, urology, and otolaryngology. Conclusion An overview of how the 5 surgical specialties are using simulation-based training to meet a wide array of educational needs for all levels of learners is presented.

The purpose of this study is to assess cardiovascular responses to lower body positive pressure (LBPP) and to examine the effects of LBPP unloading on gait mechanics during treadmill ambulation. We hypothesized that LBPP allows comfortable unloading of the body with minimal impact on the cardiovascular system and gait parameters. Fifteen healthy male and female subjects (22–55 yr) volunteered for the study. Nine underwent noninvasive cardiovascular studies while standing and ambulating upright in LBPP, and six completed a gait analysis protocol. During stance, heart rate decreased significantly from 83 ± 3 beats/min in ambient pressure to 73 ± 3 beats/min at 50 mmHg LBPP ( P < 0.05). During ambulation in LBPP at 3 mph (1.34 m/s), heart rate decreased significantly from 99 ± 4 beats/min in ambient pressure to 84 ± 2 beats/min at 50 mmHg LBPP ( P < 0.009). Blood pressure, brain oxygenation, blood flow velocity through the middle cerebral artery, and head skin microvascular blood flow did not change significantly with LBPP. As allowed by LBPP, ambulating at 60 and 20% body weight decreased ground reaction force ( P < 0.05), whereas knee and ankle sagittal ranges of motion remained unaffected. In conclusion, ambulating in LBPP has no adverse impact on the systemic and head cardiovascular parameters while producing significant unweighting and minimal alterations in gait kinematics. Therefore, ambulating within LBPP is potentially a new and safe rehabilitation tool for patients to reduce loads on lower body musculoskeletal structures while preserving gait mechanics.

The purpose of this study was to evaluate whether deeper-than-recommended insertion of a suture anchor within the rotator cuff footprint of human cadaveric humeri affects fixation characteristics. Metallic 5-mm screw-in anchors loaded with a single No. 2 suture were placed in the infraspinatus footprint of 8 human cadaveric humeri at standard and deep depths. Specimens were cyclically loaded from 10 to 45 N for 500 cycles and then loaded to failure. Cylic displacement, failure load, and failure mode were compared. All deep anchors became flush within a few cycles, and both anchor depths displaced and rotated at the bone surface. Displacement of the deep anchors was significantly greater than that of standard anchors. There was no difference in failure load. Cyclic testing showed significant displacement, regardless of anchor position, possibly leading to gap formation of the repair. Deep placement of suture anchors for increased purchase caused greater displacement and is not recommended.

Background Surgeons can control not only the angle but also the depth of suture anchor placement during arthroscopic rotator cuff repair, although the tendency may be to place suture anchors on the deep side to avoid damage from prominent anchor eyelets. However, little information is available regarding possible effects of suture anchor depth on construct failure mechanisms. Hypothesis Anchor depth affects the mode of suture failure with physiologically relevant cyclic loads. Study Design Controlled laboratory study. Methods Metallic screw-in suture anchors loaded with No. 2 braided polyester sutures were inserted into the bovine infra-spinatus footprint with the eyelet proud, standard, or deep. Sutures were hand tied to create a closed loop. Constructs were cyclically loaded from 10 to 90 N and, if still intact at 500 cycles, taken to ultimate failure (maximum load). Results When clinical failure was defined as greater than 3-mm construct elongation, anchors placed with the eyelet deep experienced statistically earlier clinical failure via cutting of the suture through the bone (P Conclusion Varying the depth of suture anchor insertion changes the mechanical properties and mode of failure of suture anchor constructs. Clinical Relevance Surgeons should be aware of the effects of suture anchor depth and abrasive eyelet wear on construct failure during arthroscopic rotator cuff repair.

Objectives To demonstrate the efficacy of compartment syndrome ultrafiltration for the treatment of acute compartment syndrome in an animal model. Our hypothesis is the removal of interstitial fluid will result in a reduction of intramuscular pressure compared with untreated controls in a model of bilateral induced compartment syndrome. Design Controlled experimental model. Setting Animal research facility. Patients/participants Three pairs of porcine hindlimbs. Intervention Acute compartment syndrome was created in the pig hindlimb by infusion of saline to maintain the intramuscular pressure 30 mm Hg greater than the animal's mean arterial pressure for 8 hours. After a 2-hour reperfusion interval, ultrafiltration (removal of fluid through 1 mm diameter porous catheters, connected to -500 mm Hg suction) was commenced in 1 limb only and continued for 9.5 hours. Main outcome measures Intramuscular pressure, ultrafiltrate volume, ultrafiltrate and serum levels of creatine kinase and lactate dehydrogenase, histologic measurement of extracellular and intracellular edema, as well as the degree of cellular necrosis. Results Intramuscular pressure tended to be lower on the treated side at the end of the treatment period [treated leg: 9.3 +/- 4.0 mm Hg (+/- SE), control leg: 19.3 +/- 1.4 mm Hg, P = 0.03]. Analysis of ultrafiltrate fluid showed that levels of creatine kinase and lactate dehydrogenase were elevated compared with serum levels. Creatine kinase levels in serum were measured at 4150 +/- 780 U/L, whereas ultrafiltrate levels of creatine kinase were 28,700 +/- 17,700 U/L (+/- SE) (P = 0.1). Lactate dehydrogenase was measured at 1950 +/- 180 U/L in serum, but markedly elevated in ultrafiltrate [160,000 +/- 88,900 U/L (+/- SE), P = 0.05]. Quantification of cellular and interstitial dimensions showed no difference in control and experimental limbs. Quantification of the degree of muscle necrosis revealed 6.1 +/- 2.7% necrosis in the treated limb compared to 11.3 +/- 1.6% necrosis in the control group (P = 0.02, df = 2, 1-tailed paired t test). Conclusion This pilot study demonstrates the feasibility of tissue ultrafiltration for reduction of intramuscular pressure in this porcine model. Further studies are underway. Compartment syndrome ultrafiltration may be useful prophylactically in patients at risk for acute compartment syndrome. Sampling of interstitial fluid and frequent measurement of intramuscular pressure may allow earlier diagnosis and treatment of acute compartment syndrome, whereas the reduction of tissue pressure by compartment syndrome ultrafiltration may prevent acute compartment syndrome from occurring. Additionally, compartment syndrome ultrafiltration will not hinder the ability of clinicians to use the clinical examination and pressure monitoring as the gold standard.

Purpose: Anchors that directly fix the rotator cuff to bone without using sutures may simplify the challenges associated with arthroscopic rotator cuff repair. This study compared a bioabsorbable screw fixation device to a standard suture anchor fixation method. Type of Study: Randomized trial. Methods: A poly-L-lactide acid (PLLA), bioabsorbable screw anchor was compared with a metallic suture anchor loaded with No. 2 braided polyester suture in 12-week-old fresh-frozen bovine shoulders. Twelve specimens were randomly assigned to the 2 repair groups (6 per group). A 1 × 2-cm defect was created at the insertion site of the infraspinatus tendon. Two anchors were implanted 1 cm apart in the anatomic insertional area of the infraspinatus tendon. After preconditioning to 10 N, each construct was cycled between 10 and 180 N for up to a maximum of 2,500 cycles at a rate of 33 mm/second using a materials testing machine. The number of cycles to 5- and 10-mm gap formation at the repair site and mode of failure were recorded. Clinically, 10-mm gap formation defines complete fixation failure. Data were evaluated using an analysis of variance with significance set at P Results: Mattress suture fixation had significantly higher number of cycles to 10-mm failure compared with the PLLA device ( P = .015). Failure occurred by tissue pullout in half the specimens and by device failure in the other half, without differences in failure modalities between groups. Conclusions: This anchor provides low-profile fixation of the rotator cuff and eliminates suture placement and knot tying during arthroscopic and mini-open cuff repair. However, these data suggest that this anchor may not perform adequately under cyclic loading conditions in patients during postoperative rehabilitation. Clinical Relevance: This bioabsorbable anchor may not provide sufficient fixation for rotator cuff repair in humans.

The primary purpose of this study was to evaluate ischemic-preconditioning (IPC) as a means of improving tolerance to ischemia-reperfusion (IR) stress on neuromuscular function. A secondary objective was to isolate the area of injury within the neuromuscular unit responsible for contractile dysfunction after IR injury. Twenty-eight male rabbits were randomly assigned to four groups (sham, IPC only, sustained ischemia only, IPC and sustained ischemia). The IPC protocol consisted of three cycles of 10 min of tourniquet-induced ischemia (125 mmHg) followed by 10 min of reperfusion. Sustained ischemia was induced by 350 mmHg external compression for 2 h. Peak tetanic tension of the tibialis anterior (TA) muscle was evaluated 48 h after the tourniquet protocol by both peroneal nerve and direct muscle stimulation, with and without pharmacologic neuromuscular junction blockade. Animals subjected to combined IPC and sustained ischemia had an equivalent loss of contractile force to those undergoing sustained ischemia alone. Two hours of tourniquet-induced ischemia resulted in marked dysfunction of the TA neuromuscular unit when evaluated by peroneal nerve stimulation (p < 0.0001). Isolation of the TA muscle from the peroneal nerve with direct muscle stimulation and neuromuscular junction blockade preserved muscle function after 3 h of ischemia. In our model, these results clearly demonstrate that IPC provides no significant protective effect from IR injury to either nerve or muscle function in our model. In addition, nerve or neuromuscular junction injury, rather than muscle damage, is identified as primarily responsible for IR-related muscle dysfunction.

Background: In recent studies, investigators have used a cyclic loading model to investigate the efficacy of rotator cuff fixation modalities.Hypothesis: A bioabsorbable poly-D-lactic acid screw and toothed washer implant will provide more stable fixation of rotator cuff repairs than standard suture anchor techniques.Study Design: Controlled laboratory study.Methods: Forty bovine shoulders (ages 3 to 6 months) had 1 × 2 cm defects created in the infraspinatus tendon. There were five repair groups (eight specimens per group) consisting of either two screw and washer implants or two suture anchors. Four suture techniques were tested: single-loaded anchors with simple sutures, double-loaded anchors with simple sutures, single-loaded anchors with horizontal mattress sutures, or single-loaded anchors with modified Mason-Allen sutures. Repairs were loaded at 5-second cycles from 10 to 180 N with use of a hydraulic testing machine. The number of cycles to gap formation of 5 and 10 mm was recorded.Results: Gap formation of 5 and 10 mm occurred significantly later for the screw repair group than for any of the suture anchor groups. There was no significant difference between suture groups.Conclusions: The bioabsorbable screw and washer provided more stable fixation than suture anchor techniques under isometric cyclic loading conditions.Clinical Relevance: This is a time-zero study of implant performance. The results indicate that the implant may decrease clinical failures in the early postoperative period under standard rehabilitation protocols.

Purpose: Females have a disproportionately high incidence of anterior cruciate ligament (ACL) injuries compared with males in analogous sports. Although the pathogenesis of this higher frequency has not been elucidated, gender differences in neuromuscular control of the knee may play an important role. This study evaluates EMG power spectra of the quadriceps and hamstring muscles during dynamic, fatiguing exercise to examine differences between male and female intercollegiate athletes. Methods: Fifty-one collegiate basketball and soccer players (25 female, 26 male) were studied. Maximum voluntary contraction (MVC) was determined for knee flexion and extension. Three consecutive 2-min bouts of isokinetic knee flexion and extension exercise were performed at 40% MVC. EMG activity in the biceps femoris and vastus medialis obliquus was recorded using bipolar surface electrodes. Results: MVC normalized to body weight was significantly greater in males than in females for the quadriceps (P < 0.01). Quadriceps coactivation ratios were significantly higher in females than in males during knee flexion exercises (P < 0.01). Conclusions: This study demonstrates differences in the EMG power spectra for females when compared with a matched group of males. Increased quadriceps coactivation in females may increase anterior tibial loads under dynamic conditions, thus placing the ACL at higher risk for injury in the female athlete.

Purpose: To assess a new method for biomechanical assessment of arthroscopic knots and to establish proficiency benchmarks using the Fundamentals of Arthroscopic Surgery Training (FAST) Program workstation and knot tester. Methods: The first study group included 20 faculty at an Arthroscopy Association of North America resident arthroscopy course (19.9 � 8.25 years in practice). The second group comprised 30 experienced surgeons attending an Arthroscopy Association of North America fall course (17.1 � 19.3 years in practice). The training group included 44 postgraduate year 4 or 5 orthopaedic residents in a randomized, prospective study of proficiency-based training, with 3 subgroups: group A, standard training (n ¼ 14); group B, workstation practice (n ¼ 14); and group C, proficiency-based progression using the knot tester (n ¼ 16). Each subject tied 5 arthroscopic knots backed up by 3 reversed hitches on alternating posts. Knots were tied under video control around a metal mandrel through a cannula within an opaque dome (FAST workstation). Each suture loop was stressed statically at 15 lb for 15 seconds. A calibrated sizer measured loop expansion. Knot failure was defined as 3 mm of loop expansion or greater. Results: In the faculty group, 24% of knots “failed” under load. Performance was inconsistent: 12 faculty had all knots pass, whereas 2 had all knots fail. In the second group of practicing surgeons, 21% of the knots failed under load. Overall, 56 of 250 knots (22%) tied by experienced surgeons failed. For the postgraduate year 4 or 5 residents, the aggregate knot failure rate was 26% for the 220 knots tied. Group C residents had an 11% knot failure rate (half the overall faculty rate, P ¼ .013). Conclusions: The FAST workstation and knot tester offer a simple and reproducible educational approach for enhancement of arthroscopic knot-tying skills. Our data suggest that there is significant room for improvement in the quality and consistency of these important arthroscopic skills, even for experienced arthroscopic surgeons. Level of Evidence: Level II, prospective comparative study.

Purpose To determine the effectiveness of proficiency-based progression (PBP) training using simulation both compared with the same training without proficiency requirements and compared with a traditional resident course for learning to perform an arthroscopic Bankart repair (ABR). Methods In a prospective, randomized, blinded study, 44 postgraduate year 4 or 5 orthopaedic residents from 21 Accreditation Council for Graduate Medical Education–approved US orthopaedic residency programs were randomly assigned to 1 of 3 skills training protocols for learning to perform an ABR: group A, traditional (routine Arthroscopy Association of North America Resident Course) (control, n = 14); group B, simulator (modified curriculum adding a shoulder model simulator) (n = 14); or group C, PBP (PBP plus the simulator) (n = 16). At the completion of training, all subjects performed a 3 suture anchor ABR on a cadaveric shoulder, which was videotaped and scored in blinded fashion with the use of previously validated metrics. Results The PBP-trained group (group C) made 56% fewer objectively assessed errors than the traditionally trained group (group A) ( P = .011) and 41% fewer than group B ( P = .049) (both comparisons were statistically significant). The proficiency benchmark was achieved on the final repair by 68.7% of participants in group C compared with 36.7% in group B and 28.6% in group A. When compared with group A, group B participants were 1.4 times, group C participants were 5.5 times, and group C PBP participants (who met all intermediate proficiency benchmarks) were 7.5 times as likely to achieve the final proficiency benchmark. Conclusions A PBP training curriculum and protocol coupled with the use of a shoulder model simulator and previously validated metrics produces a superior arthroscopic Bankart skill set when compared with traditional and simulator-enhanced training methods. Clinical Relevance Surgical training combining PBP and a simulator is efficient and effective. Patient safety could be improved if surgical trainees participated in PBP training using a simulator before treating surgical patients.

The purpose of this study was to investigate the use and validity of virtual reality modules as part of the educational approach to mastering arthroscopy in a safe environment by assessing the ability to distinguish between experience levels. Additionally, the study aimed to evaluate whether experts have greater ambidexterity than do novices.Three virtual reality modules (Swemac/Augmented Reality Systems, Linkoping, Sweden) were created to test fundamental arthroscopic skills. Thirty participants-10 experts consisting of faculty, 10 intermediate participants consisting of orthopaedic residents, and 10 novices consisting of medical students-performed each exercise. Steady and Telescope was designed to train centering and image stability. Steady and Probe was designed to train basic triangulation. Track and Moving Target was designed to train coordinated motions of arthroscope and probe. Metrics reflecting speed, accuracy, and efficiency of motion were used to measure construct validity.Steady and Probe and Track a Moving Target both exhibited construct validity, with better performance by experts and intermediate participants than by novices (P.05), whereas Steady and Telescope did not show validity. There was an overall trend toward better ambidexterity as a function of greater surgical experience, with experts consistently more proficient than novices throughout all 3 modules.This study represents a new way to assess basic arthroscopy skills using virtual reality modules developed through task deconstruction. Participants with the most arthroscopic experience performed better and were more consistent than novices on all 3 virtual reality modules. Greater arthroscopic experience correlates with more symmetry of ambidextrous performance. However, further adjustment of the modules may better simulate fundamental arthroscopic skills and discriminate between experience levels.Arthroscopy training is a critical element of orthopaedic surgery resident training. Developing techniques to safely and effectively train these skills is critical for patient safety and resident education.

To demonstrate the normal anatomy of the stabilizing structures of the lateral aspect of the knee and to investigate pathogenesis of the Segond fracture, with emphasis on the iliotibial tract (ITT) and anterior oblique band (AOB) of the fibular collateral ligament.Dissection of the region of the AOB, ITT, and lateral capsular ligament was performed in three cadaveric knees, with placement of gadopentetate dimeglumine-filled tubes along their course and tibial insertions. These knees, in addition to three nondissected knees, were studied with magnetic resonance (MR) imaging by using standard and specialized oblique planes. Specimen sectioning provided anatomic correlation. Retrospective review of radiographs and MR images in 17 patients with acute Segond fractures was performed, and the relationship between the fragment and the demonstrated lateral supporting structures of the knee was noted.Anatomic dissection and MR imaging of the cadaveric knees demonstrated a broad tibial insertion of the ITT, with fibers extending posterior to the Gerdy tubercle. A firm band of tissue, the AOB, extended from the fibular collateral ligament to the midportion of the lateral tibia, the typical site of a Segond fracture. The lateral capsular ligament proved to be a mere thickening of the capsule, inserting at the lateral tibia. Clinical analysis of acute Segond fractures confirmed the frequent attachment of the ITT and AOB to the avulsed fragment.Anatomic and clinical findings suggest that fibers of the ITT and AOB are important factors in the pathogenesis of the Segond fracture.

Objective: To compare the sensitivity of conventional MR sequences, MR arthrography, and CT arthrography for the detection of cartilage lesions of the patella in cadavers. Material and Methods: Cartilage lesions in 10 cadaveric specimens were evaluated by MR imaging, including T1-weighted, proton density-weighted and T2-weighted sequences, and fat-suppressed spoiled gradient recalled acquisition in the steady state (SPGR), MR arthrography including T1-weighted and SPGR sequences, and double-contrast CT arthrography including conventional and subtracted images. The sensitivities with regard to detection of lesions were compared to results from morphologic and histologic investigations of sectioned specimens. Results: Twenty-one lesions were detected morphologically. For the detection of these lesions, sensitivities were as follows: T1-weighted images 33.3%; proton density-weighted images 85.7%; T2-weighted images 85.7%; SPGR images 80.9%; MR arthrography with T1-SE sequences 57.1%; MR arthrography with SPGR sequence 90.5%; and CT arthrography, both regular and subtracted images 85.7%. Conclusion: For noninvasive techniques, T2-weighted images revealed the highest sensitivity for the detection of patellar cartilage lesions, which was surpassed only by MR arthrography using the SPGR sequence. CT arthrography delineated surface irregularities but failed to demonstrate intrachondral lesions.

Objective. The objective of this study was to illustrate the magnetic resonance (MR) image appearance of the structures of the posteromedial ”corner” of the knee with particular emphasis on the anatomy and differentiation between the medial collateral ligament and the posterior oblique ligament. Design. Six cadaveric knee specimens underwent MR imaging, before and following instillation of intra-articular contrast material. The knees were sectioned in the axial, coronal, and coronal oblique planes and the gross morphology of the posteromedial corner and surrounding structures was studied and correlated with the MR images. Patients. The human cadaveric specimens were from two female and four male patients (age at death, 72–86 years; average, 78 years). Results and conclusions. The contrast-enhanced sequences and the coronal oblique images allowed for improved visualization of the structures.

Neuromuscular function in New Zealand White rabbits was evaluated after thigh tourniquet compression in the directly compressed quadriceps muscles and the distal tibialis anterior by measuring isometric contractile function after supramaximal stimulation of the motor nerve. Tourniquet compression resulted in markedly decreased force production beneath and distal to the tourniquet. Two days after compression, maximal quadriceps force production was decreased to 46% of control values with 125 mm Hg compression and 21% of control values after 350 mm Hg compression. Maximum tibialis anterior force production declined to 70% of control values after 125 mm Hg thigh compression and 24% of control values after 350 mm Hg thigh compression. Functional deficits were greater in the directly compressed quadriceps muscles, but the quadriceps and tibialis anterior had significantly increased impairment when the tourniquet inflation pressure was increased from 125 mm Hg to 350 mm Hg. Three weeks after compression, quadriceps function had returned to 94% of control value after 125 mm Hg compression and 83% after 350 mm Hg. Tibialis anterior function returned to 88% of control values after 125 mm Hg thigh compression and 83% after 350 mm Hg. Clinically, the use of lower inflation pressures may minimize the complications of tourniquet use and enhance postoperative recovery.

The objective of this pictorial essay is to illustrate the MR appearance of the common peroneal nerve and the appearance of masses that have been associated with peroneal nerve entrapment. Four human cadaveric knees underwent axial MRI utilizing a T1-weighted SE sequence. One knee was dissected by an orthopedic surgeon and three knees were transversely sectioned, and the gross morphology of the common peroneal nerve and the perineural structures was evaluated and correlated with the MR images.

Exertional compartment syndrome is characterized by intracompartmental pressures that rise transiently following repetitive motion or exercise, thereby producing temporary, reversible ischemia, pain, weakness, and, occasionally, neurologic deficits. The exact cause or pathogenesis remains unclear; a disturbance of microvascular flow caused by elevated intramuscular pressure leads to tissue ischemia, depletion of high-energy phosphate stores, and cellular acidosis. Anatomic contributing factors may include a limited compartment size, increased intracompartmental volume, constricted fascia, loss of compartment elasticity, poor venous return, or increased muscle bulk. The diagnosis is suspected based on history and confirmed with physical examination and intramuscular pressure evaluation before and after exercise (stress test). Differential diagnosis includes claudication or other vascular abnormalities, myositis, tendinitis, periostitis, chronic strains or sprains, stress fracture, other compression or systemic neuropathies, and cardiac abnormalities with angina or referred extremity pain. Initial treatment includes activity modification; refractory symptoms can be managed with elective fasciotomy.

The purpose of this study was to evaluate the accuracy of cortical measurements of experimentally created endosteal cortical lesions and to assess the sensitivity of radiography, CT, and MR imaging in the detection and measurement of such lesions.Thirty-six cortical lesions were created in three fresh cadaveric femurs. After performing radiography, CT, and MR imaging, we sectioned the specimens in the axial plane. We then measured the remaining cortex at the lesions and the normal cortex adjacent to the lesions on all images and corresponding anatomic sections. The measurements of thickness of the cortex as seen with the different imaging methods and the anatomic sections were compared. Measurements were repeated to evaluate the influence of different window settings on the MR imaging measurements.When measured on radiographs, cortical thickness was overestimated in 58% of lesions. With CT, cortical thickness was overestimated by 0-15% in 94% of all lesions. With MR imaging, cortical thickness was uniformly underestimated by 3-17%. Measurements made on MR images varied according to different window settings. The proton density-weighted sequence yielded the highest sensitivity in the detection of shallow cortical lesions; the T1-weighted spin-echo sequence was the least sensitive of the MR sequences.In our cadaveric study, cortical thickness in the presence of endosteal lesions was overestimated on radiographs and CT scans and underestimated on MR images. Measurements derived from MR imaging are strongly influenced by the window setting. MR imaging with the proton density-weighted sequence is the most sensitive for detection of shallow cortical lesions and is more sensitive than CT.

Currently, the definitive diagnosis of chronic compartment syndrome is based on invasive measurements of intracompartmental pressure. We measured the intramuscular pressure and the relative oxygenation in the anterior compartment of the leg in eighteen patients who were suspected of having chronic compartment syndrome as well as in ten control subjects before, during, and after exercise. Chronic compartment syndrome was considered to be present if the intramuscular pressure was at least fifteen millimeters of mercury (2.00 kilopascals) before exercise, at least thirty millimeters of mercury (4.00 kilopascals) one minute after exercise, or at least twenty millimeters of mercury (2.67 kilopascals) five minutes after exercise. Changes in relative oxygenation were measured with use of the non-invasive method of near-infrared spectroscopy. In all patients and subjects, there was rapid relative deoxygenation after the initiation of exercise, the level of oxygenation remained relatively stable during continued exercise, and there was reoxygenation to a level that exceeded the pre-exercise resting level after the cessation of exercise. During exercise, maximum relative deoxygenation in the patients who had chronic compartment syndrome (mean relative deoxygenation [and standard error], -290 +/- 39 millivolts) was significantly greater than that in the patients who did not have chronic compartment syndrome (-190 +/- 10 millivolts) and that in the control subjects (-179 +/- 14 millivolts) (p < 0.05 for both comparisons). In addition, the interval between the cessation of exercise and the recovery of the pre-exercise resting level of oxygenation was significantly longer for the patients who had chronic compartment syndrome (184 +/- 54 seconds) than for the patients who did not have chronic compartment syndrome (39 +/- 19 seconds) and the control subjects (33 +/- 10 seconds) (p < 0.05 for both comparisons).

To evaluate short echo time (TE) projection reconstruction magnetic resonance (MR) imaging in the detection of cartilage lesions.Twenty-seven cartilage regions of 10 human patellar specimens were examined with the following MR sequences: short TE projection reconstruction (repetition time msec/TE msec, 400/0.15), fat-suppressed three-dimensional spoiled gradient-recalled acquisition in the steady state (Spoiled GRASS) (50/10, 60 degrees flip angle), and magnetization transfer contrast (MTC) subtraction (400/6). MR findings were correlated with histopathologic grading of the cartilage.For detection of cartilage lesions, sensitivity of projection reconstruction imaging (100%) was significantly greater (P = .03) than that of MTC (62%) but not significantly greater (P.05) than that of Spoiled GRASS (81%) imaging. Accuracy of projection reconstruction was significantly greater than that of MTC (P = .004) and Spoiled GRASS (P = .03) imaging. Unmasking of collagen fibers was most predictive of abnormal signal intensity of the cartilage with all sequences.In vitro, short TE projection reconstruction MR imaging provides superior delineation of cartilage lesions when compared with two other sequences. On Spoiled GRASS and MTC images, signal intensity of the superficial layer of cartilage is not a reliable sign for surface integrity.

Purpose: To establish the metrics (operational definitions) necessary to characterize a reference arthroscopic Bankart procedure, and to seek consensus from experienced shoulder arthroscopists on the appropriateness of the steps, as well as errors identified. Methods: Three experienced arthroscopic shoulder surgeons and an experimental psychologist (comprising the Metrics Group) deconstructed an arthroscopic Bankart procedure. Fourteen full-length videos were analyzed to identify the essential steps and potential errors. Sentinel (i.e., more serious) errors were defined as either (1) potentially jeopardizing the procedure outcome or (2) creating iatrogenic damage to the shoulder. The metrics were stress tested for clarity and the ability to be scored in binary fashion during a video review as either occurring or not occurring. The metrics were subjected to analysis by a panel of 27 experienced arthroscopic shoulder surgeons to obtain face and content validity using a modified Delphi Panel methodology (consensus opinion of experienced surgeons rendered by cyclical deliberations). Results: Forty-five steps and 13 phases characterizing an arthroscopic Bankart procedure were identified. Seventy-seven procedural errors were specified, with 20 designated as sentinel errors. The modified Delphi Panel deliberation created the following changes: 2 metrics were deleted, 1 was added, and 5 were modified. Consensus on the resulting Bankart metrics was obtained and face and content validity verified. Conclusions: This study confirms that a core group of experienced arthroscopic surgeons is able to perform task deconstruction of an arthroscopic Bankart repair and create unambiguous step and error definitions (metrics) that accurately characterize the essential components of the procedure. Analysis and revision by a larger panel of experienced arthroscopists were able to validate the Bankart metrics. Clinical Relevance: The ability to perform task deconstruction and validate the resulting metrics will play a key role in improving surgical skills training and assessing trainee progression toward proficiency.

Purpose Our goals were (1) to characterize metal microparticles created by standard arthroscopic instruments and (2) to examine the in vitro cellular responses induced by those particles, including possible synergistic effects with local anesthetic. Methods We applied standard surgical tools to 16 foam bone blocks immersed in saline solution (plus 3 non-instrumented controls). Eight specimens underwent 4 minutes of exposure to a 4.0-mm full-radius shaver rotating forward at 6,000 rpm. In the other blocks, 4 holes were created with a 3.0-mm drill through a sleeve. Particles were isolated onto silicon wafers by density gradient ultra-centrifugation, and scanning electron microscopy was used to analyze a minimum of 1,000 particles per wafer. Metal particles were then isolated and purified. Aliquots of sterilized micro-particles were applied to cultured bovine chondrocytes (with or without local anesthetic) and to cultured human or bovine synoviocytes. Chondrocyte viability was assessed with live/dead cell assay by flow cytometry. Synoviocyte responses were assessed with quantitative polymerase chain reaction. Results Stainless steel or aluminum particles were found in each sample (the same composition as surgical instruments). The mean particle size was 1 to 2 μm (range, 50 nm to 20 μm). Chondrocyte exposure (1 hour) to metal debris induced a small but statistically significant increase in cell death, without any synergistic effect of local anesthetic. Proinflammatory chemokines were consistently upregulated in both human and bovine synoviocytes exposed to metallic microparticles for 3, 24, and 48 hours. Conclusions This study shows that metallic microdebris is liberated by common arthroscopic instruments, at scales much smaller than previously recognized. These particles are bioactive, as shown by the in vitro synoviocyte responses initiated by metallic microparticles. Clinical Relevance Our findings suggest that metallic microparticles could induce intra-articular damage through a synoviocyte-mediated cytokine response if their concentrations reach clinically significant levels.

Background: Acquisition of surgical skills through laboratory-based training and simulation is appealing to surgical training programs. The purpose of this study was to provide baseline information on the current use of surgical skills training laboratories in orthopaedic resident education and to determine the interest in expansion of these facilities and training techniques. Methods: The creation of the survey was a collaborative effort between the authors and the American Academy of Orthopaedic Surgeons (AAOS). Two online versions of the Surgical Skills Simulation survey were created, one (with twenty-three items) specifically for program directors and one (with fourteen items) for orthopaedic residents. The survey was sent via e-mail to 185 program directors and 4549 residents. Data were retrieved and analyzed by the AAOS Department of Research and Scientific Affairs. Results: Eighty-six (46%) of the 185 surveys distributed to orthopaedic surgery residency directors and 687 (15%) of the 4549 distributed to orthopaedic surgery residents were completed. Seventy-six percent of the program directors reported having a surgical skills laboratory, and 46% of these reported having a structured surgical skills laboratory curriculum. Fifty-eight percent of program directors and 83% of residents believed that surgical skill improvement by orthopaedic residents was not being objectively measured. Both 80% of program directors and 86% of residents agreed that surgical skills simulations should become a required part of training, and 82% and 76% were interested in a standardized surgical skills curriculum. Eighty-seven percent of program directors identified a lack of available funding as the most substantial barrier to development of a formal surgical skills program at their institution. Conclusions: There was strong agreement among both program directors and residents that surgical skills laboratories and simulation technology should be a required component of orthopaedic resident training. At the present time, the most substantial barrier to adoption of surgical skills laboratories and a formalized surgical skills curriculum is the lack of funding.

To compare magnetic resonance (MR) imaging and MR arthrography with computed tomography (CT) and CT arthrography in the detection of intraarticular bodies in the knee.Cuboid (3- or 6-mm-long sides) osseous and cartilaginous bodies were implanted in 16 cadaveric knee specimens. MR imaging was performed with T1-weighted spin-echo (SE), T2-weighted SE, proton-density-weighted SE, gradient recalled acquisition in the steady state (GRASS), and spoiled GRASS sequences. MR arthrography was performed in two phases with saline and 2 mmol/L gadopentetate dimeglumine. CT and CT arthrography were performed in the transaxial plane.MR arthrography yielded the highest accuracy for the detection of osseous and cartilaginous bodies combined (92%) and was significantly (P.01) better than MR imaging (57%-70%), CT arthrography (80%), and CT (74%). Accuracy of CT arthrography was significantly better than that of MR imaging and that of CT. Accuracy of saline-enhanced MR arthrography was significantly inferior (P.001) to that of gadolinium-enhanced MR arthrography.MR arthrography is the best imaging technique for detection of individual intraarticular bodies. CT arthrography is the second most accurate method. Spoiled GRASS and T2-weighted SE sequences are the most accurate at MR imaging. The presence of intraarticular fluid and performance of saline-enhanced MR arthrography improve detectability of intraarticular bodies.

Cystic degeneration of the meniscus is not uncommon. Recent reports suggest that most (or all) meniscal cysts are associated with a meniscal tear, and that the treatment of choice is arthroscopic partial meniscectomy with cyst decompression. This report describes a case of a symptomatic lateral meniscal cyst that was suspected clinically and confirmed by magnetic resonance imaging, but was not associated with a meniscal tear at arthroscopy. Open cyst extirpation and peripheral meniscal repair were performed to maximize preservation of meniscal tissue. A clinical algorithm is presented for management of meniscal cysts.