Operative repair of the rotator cuff (RC) of the shoulder can return a patient to normal function but is not without complications. An understanding of the tissue strains in the RC of the shoulder under normal and pathological conditions can inform surgeons about the conditions needed for restoration of function and the state of the tissue under repair. The current work applied digital image correlation (DIC) to quantify rotator cuff strains with the goals of (1) determining whether the tension created by the supraspinatus (SS) muscle is transmitted without diversion by the structure of the cuff from the supraspinatus to the cuff insertion; and (2) whether releases of the SS tendons at their insertions alter the strain field in the region away from the cuff insertion. DIC methods recorded the bursal-side cuff strains created using a shoulder simulator, which could apply physiologic loads to the cuff muscles. The SS and infraspinatus (IS) insertions of the humerus were sequentially released while muscle loads were applied. The first principal strains and their directions showed changes after releases of both the anterior and posterior SS insertions and after the IS release. The results demonstrated (1) that the RC transmits SS muscle forces without diversion and (2) that RC releases do affect the strain field. Release of both heads of the SS led to statistically significant changes in strain magnitude and direction.

Surgical interventions for ulnar neuropathy are typically identified as releases or decompressions. With the expectation that ulnar nerve strain contributes to cubital tunnel syndrome and with the basic hypothesis that nerve tension will most significantly increase in positions of highest elbow flexion, wrist extension, and classic sites of compression, we initiated a new experimental technique to quantify strain and tension in the ulnar nerve. In five fresh-frozen cadaveric upper extremities from the spine to the wrist, we percutaneously placed small radiopaque spheres into the ulnar nerve using ultrasound guidance to allow tracking of ulnar nerve motion and elongation under fluoroscopy. This technique caused minimal disruption to the soft tissues tethering the nerve. In a custom jig, the forearm was fixed in space while varying elbow and wrist range of motion. After removal of the hand, we measured nerve motion and the tensions constraining the nerve using proportional techniques with application of loads at four standardized locations between the radiocarpal joint and elbow. Means of all in situ tensions varied from 0.54 to 4.28 N. There were significant differences in these constraints tensions among the different elbow flexion angles (p = 0.020). There were differences in in situ tension at the sites of constraint but consistent strains across all four sites. The fluoroscopic technique with percutaneous marker placement successfully allowed strain and tension measurements. The differences in tensions but consistent strains suggest that surgical repair with attention to the attachment of the nerve might restore native nerve gliding and mechanical behavior.

This study evaluated the effect of the lacertus fibrosus on the biceps brachii moment arms to determine the lacertus importance in forearm strength. The work proceeded from the null hypothesis that the lacertus fibrosus has no effect on flexion/extension and supination/pronation.Ten fresh-frozen cadaveric specimens were mounted in an elbow simulator to measure tendon excursion, elbow flexion/extension (FE) and forearm pronation/supination (PS) angles. FE moment arms were calculated throughout FE excursion at multiple, constant PS angles and PS moment arms were measured throughout PS excursion at multiple, constant FE angles. Tests included the lacertus intact, the superficial lacertus transected, and the entire lacertus transected along with any connections to surrounding tissue.The intact lacertus increased the FE moment arm of the biceps with the elbow in less than 40° flexion and decreased the FE moment arm with the elbow in greater than 80° flexion, where the decrease could exceed 50%, depending on the flexion angle. The intact lacertus decreased the PS supination moment arm at all flexion angles; the intact lacertus even caused the biceps to act as a pronator at full elbow extension.The intact lacertus assists in early elbow flexion and the lacertus hinders elbow flexion at greater than 80° flexion. The lacertus hinders the biceps function of supination, especially in a supinated position. Injury of the lacertus without direct biceps tendon damage can be tested best at the ends of the flexion ROM and at higher supination angles. Lacertus syndrome may be more quickly diagnosed with provocative tests that isolate the lacertus function.

Background: The supraspinatus (SS) is formed by a larger anterior bipennate muscle with a cord-like tendon and a posterior unipennate muscle with a strap-like tendon. There is a tendinous connection between the 2 SS subunits. Yet, the relative mechanical contribution of the SS cord and SS strap musculotendinous units to load transmission and subsequent shoulder abduction force is unknown. We hypothesized that a simulated SS cord vs. an SS strap tear would generate less shoulder abduction force and, further, an intact SS cord would offset the expected abduction loss from an SS strap tear, but the inverse would not be true.Materials and Methods: Twenty fresh-frozen cadaveric specimens were tested in a shoulder simulator with physiological load vectors applied to the upper and lower subscapularis, SS cord, SS strap, infraspinatus, and teres minor. The roles of the SS cord and SS strap muscles were delineated by varying their loads, while keeping constant loads on other muscles. The randomized testing trials included a native condition and 4 test cases that simulated tears by dropping the load and force transfer via the SS cord-to-SS strap connection by adding the load. Testing was completed at both 0 degrees and 30 degrees of abduction. During each test, shoulder abduction force, rotator cuff strains, and humeral translation were measured.Results: Simulated isolated SS cord and SS strap tears led to a significantly lower shoulder abduction force (P < .001). A simulated cord tear at 0 degrees and 30 degrees reduced the abduction force by 53% and 38%, respectively. A simulated strap tear at 0 degrees and 30 degrees dropped the abduction force by 27% and 23%, respectively. The decline in the abduction force was larger for the SS cord tear vs. SS strap tear (P <= .001). An SS cord tear with full-load transfer to the strap was able to recover to native values at both 0 degrees and 30 degrees (P >= .288). Likewise, an SS strap tear with full-load transfer to the SS cord showed a similar recovery to native values at both 0 degrees and 30 degrees (P >= .155). During full-load transfer, the tendon strain followed the loading pattern. An SS cord tear or SS strap tear did not cause a change in humeral translation (P >= .303).Discussion: The mechanical findings support the efficacy of nonoperative treatment of small (<10 mm) SS tears,(11 )because an intact SS strap tendon can effectively offset the abduction loss of a torn SS cord tear and vice versa.Level of evidence: Basic Science Study; Biomechanics (c) 2023 The Author(s). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).

Importance Patients with excessive posterior tibial slope (PTS) may have higher risks of anterior cruciate ligament (ACL) reconstruction (ACL-R) failure, and clinical outcomes after revision ACL-R procedures are typically poor. Objective To perform a systematic review of the literature summarizing the clinical and radiological outcomes of the surgical treatment of ACL insufficiency in the setting of excessive PTS using a tibial deflexion osteotomy combined with ACL-R. Evidence Review A systematic review of the literature was performed using PubMed, Cochrane Library, and OVID Medline databases from 1990 to present. Inclusion criteria were: studies of outcomes of isolated tibial deflexion osteotomies performed with primary or revision ACL-R in the English language. Data extracted included study demographic information, type of tibial deflexion osteotomy and concomitant procedures, radiological outcomes, patient reported outcome scores, and postoperative complications Findings Six studies, with 133 knees were identified. All included studies were retrospective case series, with a weighted mean follow-up of 3.39 years. In 106 of 133 (79.7%) knees, tibial deflexion osteotomy was performed concomitantly with an ACL-R, whereas in 27 of 133 (20.3%) knees the procedures were staged. 22, 45, and 66 of 133 knees (16.5%, 33.8%, and 49.6%) underwent primary, 1st revision, and 2nd or greater revision ACL-R, respectively. 3 of 133 (2.25%) knees demonstrated recurrent ACL graft failure at final follow-up. On average, PTS decreased from 15.2 degrees preoperatively to 7.1 degrees postoperatively. Mean International Knee Documentation Committee (IKDC), Lysholm, and Tegner scores increased from 42.5, 46.4, and 4.2 preoperatively to 71.8, 89.0, and 6.7 postoperatively. Conclusions The results of this review suggest that combined ACL-R and tibial deflexion osteotomy may be effective in decreasing PTS and improving knee function and stability. Study Design Systematic Review; Level of evidence 4

Background: Many techniques are used for digital nerve repair, most commonly coaptation by sutures. Nerve repairs must be strong while offering an environment for nerve regeneration. Sutures can damage the nerve and thereby limit growth and regeneration. Sutures can rip and cause sudden catastrophic failure. Fibrin glue and conduit-wraps allow a good environment for growth, but neither provides much strength. A benefit to conduit repair would arise if the repair maintained integrity after the peak load so that the path for regrowth stayed in place. The goal for this study was to determine whether conduit with glue provides continued strength after a maximum load is reached. Methods: Digital cadaveric nerves were harvested and repaired with 2 epineurial sutures, conduit, and fibrin glue in all combinations. Tests to failure were performed, gap displacement between nerve ends recorded, and the postpeak load energy to dissociation of the nerve and conduit was calculated. Results: Conduit with glue and 2 sutures at the end had the greatest energy and displacement after the peak load but was not significantly different than conduit with glue and 1 suture. Conduit with glue alone obtained statistically the same displacement as conduit with glue and 2 sutures. Conduit, with or without glue, and 2 sutures was statistically the same as suture only repair for peak load. Conclusion: Conduit/wrap maintains a load capacity and a path for nerve regeneration after the peak. Suture at the ends of conduit, not at the coaptation site, reduces damage at the point of injury.

Hypothesis:Single-incision biceps tendon repair with an arthrotunneling device has previously been shown to be a safe and effective technique that provides the anatomic restoration of a two-incision approach and a reduced complication profile. This repair provides adequate and comparable fixation to repairs utilizing anchors, buttons, screws, etc., at a lower cost.Material and methods:This study utilized 10 cadaveric specimens. Native and repair specimens were cyclically loaded and graft displacement, flexion/extension (FE) and pronation/supination (PS) moment arms at 12.5° to 152.5° (in 5° increments) before and after repair, and maximum load to failure were measured.Results:The FE and PS moment arms and overall maximum moment arms were both significantly larger in the repaired case than in the native case (p < 0.01). Moment arms for supinated specimens were significantly greater than neutral specimens, which in turn was greater than pronated specimens (p < 0.01). The maximum load up to 10 mm of repair displacement was 214.5.0 ± 66.6 N and the repair displacement due to 1000 cycles of 50 N was 2.56 ± 2.06 mm.Conclusion:The single-incision arthrotunneling technique is a safe and effective repair that recreates the anatomic footprint and biomechanics of the native biceps and has a reduced complication profile compared to a two-incision approach.

A study was undertaken to determine how well contacting fracture fragments of composite bone replicated the behavior of fracture fragments in real bone. Ten composite and ten real humeral diaphyses were transected and reconstructed with limited-contact dynamic-compression plates. Two screws were placed on each side of the transection site and a calibrated electronic sensor sheet was placed between the imitated fracture fragments. After insertion of the distal screws, pressure measurements were made during insertion of the first proximal screw in compression mode, during insertion of the second screw in compression mode after loosening the first screw, and finally after retightening the first screw. The process was repeated after bending the plate. The contact area, the net compression force and the average compressive stress were computed and statistically compared. The composite bone and cadaveric bone differed in contact area and compressive stress but not in net compressive force. Plate bending did not produce a significant difference between composite and cadaveric bone. The results indicate that composite bone does not reproduce all the local fracture fragment conditions so that hardware testing in composite bone should proceed carefully. A gap between fracture fragments as is often used in comminuted fracture tests may remain as the most appropriate situation for fracture hardware testing.

Anterior cruciate ligament (ACL) injuries to soccer players present unique challenges in sports medicine, given the sport’s global prevalence and intricate injury dynamics. These injuries, especially in the youth and female demographic, have become a substantial concern in sports medicine. This review explores the epidemiology, mechanism of injury, diagnostic procedures, treatment modalities, and rehabilitation strategies related to ACL tears within the soccer community. Progress in diagnostics, treatments, and rehabilitation underscores the importance of evidence-based approaches. As soccer continues its ascent in popularity, addressing the specific risks and nuances of ACL injuries in this context remains of paramount significance.

Multiligament knee injuries (MLKIs) represent a broad spectrum of pathology with potentially devastating consequences. Currently, disagreement in the terminology, diagnosis and treatment of these injuries limits clinical care and research. This study aimed to develop consensus on the nomenclature, diagnosis, treatment and rehabilitation strategies for patients with MLKI, while identifying important research priorities for further study. An international consensus process was conducted using validated Delphi methodology in line with British Journal of Sports Medicine guidelines. A multidisciplinary panel of 39 members from 14 countries, completed 3 rounds of online surveys exploring aspects of nomenclature, diagnosis, treatment, rehabilitation and future research priorities. Levels of agreement (LoA) with each statement were rated anonymously on a 5-point Likert scale, with experts encouraged to suggest modifications or additional statements. LoA for consensus in the final round were defined 'a priori' if >75% of respondents agreed and fewer than 10% disagreed, and dissenting viewpoints were recorded and discussed. After three Delphi rounds, 50 items (92.6%) reached consensus. Key statements that reached consensus within nomenclature included a clear definition for MLKI (LoA 97.4%) and the need for an updated MLKI classification system that classifies injury mechanism, extent of non-ligamentous structures injured and the presence or absence of dislocation. Within diagnosis, consensus was reached that there should be a low threshold for assessment with CT angiography for MLKI within a high-energy context and for certain injury patterns including bicruciate and PLC injuries (LoA 89.7%). The value of stress radiography or intraoperative fluoroscopy also reached consensus (LoA 89.7%). Within treatment, it was generally agreed that existing literature generally favours operative management of MLKI, particularly for young patients (LoA 100%), and that single-stage surgery should be performed whenever possible (LoA 92.3%). This consensus statement will facilitate clinical communication in MLKI, the care of these patients and future research within MLKI.

Background Open fibular fixation with plate osteosynthesis as an adjunct to increase stability has been associated with wound complications. Various percutaneous treatment options have been explored, but incompletely evaluated in comparison to one another in terms of rigidity of fixation at the fracture site. Methods A biomechanical study was performed with 9 pairs of matched cadavers after creation of a suprasyndesmotic fracture model as occurs in association with a tibial pilon fracture. One group in each pair was assigned to threaded screw and the other to smooth pin fixation. Displacement at the fracture site was evaluated before and after cyclic axial and rotational loading with an MTS frame through video dimensional analysis. Results In vertical loading alone, smooth pin and threaded screw fixation demonstrated no significant difference in displacement and there was no change in performance before and after loading cycles. With external rotation combined with a modest vertical load, screw fixation demonstrated smaller displacements than pin fixation, but the difference was less than 1 mm. Conclusions The results suggest that both smooth pin fixation and threaded screw fixation can achieve stable fixation in a transverse fibular fracture. There is less motion with use of a threaded screw when loading in axial rotation and external rotation, potentially recommending this option as a more rigid construct for percutaneous fixation of simple fracture patterns.

BackgroundUlnar nerve compression at the elbow is the second most common compressive neuropathy of the upper extremity. We hypothesize that tension on the ulnar nerve produced by elbow flexion and distraction contributes to this condition. We measured ulnar nerve tension generated during elbow flexion and proportional distraction to evaluate locations of soft tissue constraints to nerve translation.MethodsEight fresh-frozen upper limb specimens were tested. Each specimen included the proximal humeral shaft to the wrist. The ulnar nerve was dissected proximally and clamped to the humerus 8 ​cm proximal to the medial epicondyle. At 8 ​cm distal to the medial epicondyle, the ulnar nerve was dissected and clamped distally to a load cell that was mounted on a laboratory stand. A stage on the stand could be translated distally to apply load. Soft tissue was removed distal to the load cell clamp; all soft tissue from the load cell to the proximal humeral clamp was left intact.We measured the tension generated on the nerve throughout the full arc of elbow flexion with additional distal distractions of 0%, 2.5% and 5% of nerve length applied by distal translation of the stage on the lab stand. We then repeated these steps with the nerve unclamped proximally. We then excised 1 ​cm of soft tissue distally, clamped the nerve 7 ​cm distal to the medial epicondyle, and repeated the measurements. We continued this sequential dissection and testing until the nerve was clamped to the load cell 1 ​cm distal to the medial epicondyle.ResultsFlexion, distraction, and proximal clamping each increased nerve tension. Tension was greatest at 4, 5, and 6 ​cm distal to the medial epicondyle (p ​< ​0.01).ConclusionFlexion, distraction, and proximal clamping each increased ulnar nerve tension. The greatest ulnar nerve tension was recorded between 4 and 6 ​cm distal to the medial epicondyle.

Background: Knee fracture-dislocations are complex injuries; however, there is no universally accepted definition of what constitutes a fracture-dislocation within the Schenck Knee Dislocation (KD) V subcategory. The purpose of this study was to establish a more precise definition for fracture patterns included within the Schenck KD V subcategory. Methods: A series of clinical scenarios encompassing various fracture patterns in association with a bicruciate knee ligament injury was created by a working group of 8 surgeons. Utilizing a modified Delphi technique, 46 surgeons from 18 countries and 6 continents with clinical and academic expertise in multiligamentous knee injuries undertook 3 rounds of online surveys to establish consensus. Consensus was defined as ≥70% agreement with responses of either “strongly agree” or “agree” for a positive consensus or “strongly disagree” or “disagree” for a negative consensus. Results: There was a 100% response rate for Rounds 1 and 2 and a 96% response rate for Round 3. A total of 11 fracture patterns reached consensus for inclusion: (1) nondisplaced articular fracture of the femur; (2) displaced articular fracture of the femur; (3) tibial plateau fracture involving the weight-bearing surface (with or without tibial spine involvement); (4) tibial plateau peripheral rim compression fracture; (5) posterolateral tibial plateau compression fracture, Bernholt type IIB; (6) posterolateral tibial plateau compression fracture, Bernholt type IIIA; (7) posterolateral tibial plateau compression fracture, Bernholt type IIIB; (8) Gerdy’s tubercle avulsion fracture with weight-bearing surface involvement; (9) displaced tibial tubercle fracture; (10) displaced patellar body fracture; and (11) displaced patellar inferior pole fracture. Fourteen fracture patterns reached consensus for exclusion from the definition. Two fracture patterns failed to reach consensus for either inclusion or exclusion from the definition. Conclusions: Using a modified Delphi technique, this study established consensus for specific fracture patterns to include within or exclude from the Schenck KD V subcategory. Level of Evidence: Prognostic Level V. See Instructions for Authors for a complete description of levels of evidence.

Background:Partial distal biceps tears can occur in the short and/or long heads, leading to forearm pain and weakness. Yet, the pathoanatomy of atraumatic and traumatic partial tears are not understood. The goals of this study are to determine the distal biceps partial tear frequency and tear pattern in a cohort of cadaveric specimens.Methods:Fifty three fresh frozen cadavers (average age 70.4 ± 13.8 years, range 32-94) underwent elbow endoscopy to screen for partial tears. The partial tendon tear pattern was classified into either attritional (atraumatic), detachment on the tendon's lateral side, or avulsion (traumatic) rupture of the tendon fibers from bone on both the lateral and medial sides. The specimens were dissected and laser scanned to make 3D models. The tear location, shape, and area were calculated using gross dissection and the 3D models.Results:Atraumatic partial distal biceps tears were identified in 40% of the specimens, 72% involved both the long and short heads, 14% long head, and 14% short head. In all tears, the tendon fibers were only detached from the lateral side. The greatest tear width occurred near the short and long head junction.Conclusion:Atraumatic partial distal biceps tears are common. The tear originates on the lateral side of the tendon at the short and long head junction. All the tear patterns are attritional and no specimen had surgical treatment. This finding supports the current treatment recommendation of an initial period of nonoperative care for symptomatic atraumatic partial distal biceps tears.

Background: Floating shoulder injuries cause instability and deformity due to disruptions of the scapula, clavicle, and superior shoulder suspensory complex ligaments (SSSC). Resulting deformity of the glenopolar angle (GPA) has not previously been established, nor has the impact on stability and deformity when surgical fixation is performed. This study sought to quantify stability and deformity for mul-tiple injury patterns and the improvement to these parameters provided by clavicle and coracoclavicular (CC) ligament fixation.Methods: Fourteen cadaveric specimen upper extremities were used, which included the entire upper extremity, scapula, clavicle, and cranial-most ribs. After being mounted upright, a scapular neck fracture was created, followed by either a midshaft clavicle fracture or sectioning of the acromioclavicular and coracoacromial ligaments. Subsequent sectioning of the other structure(s) followed by the CC ligaments was then performed. In all specimens, the clavicle was then plated, followed by a CC ligament repair. At each step, a radio-graph in the AP plane of the scapula was taken to measure GPA and displacement of the glenoid fragment using radiopaque markers placed in the scapula. These radiographs were taken both unloaded and with a 100-N applied medializing force. Results: When evaluating deformity related to sectioning, the GPA was reduced when the CC ligaments were sectioned compared to an isolated scapula fracture (P = .022) and compared to a combined scapula and clavicle fracture (P = .037). For stability, displacement with a 100-N force was significantly increased when the CC ligaments were sectioned compared to an isolated scapula fracture (P = .027). In cases of an ipsilateral scapula neck and clavicle fracture with intact ligaments, fixation of the clavicle alone provided a statistically significant improvement in the GPA (P = .002); but not in reduction of displacement (P = .061). In cases of an ipsilateral scapula neck and clavicle fracture with concomitant disruption of the coracoacromial, acromioclavicular, and CC ligaments, the GPA was improved by clavicle fixation (P < .001) and increasingly so by subsequent CC ligament repair (P < .001). Displacement was also improved in these 2 states (P < .001, P = .008, respectively).Discussion: This biomechanical study confirmed the importance of the acromioclavicular, coracoacromial, and CC ligaments in confer-ring stability in SSSC injuries. Disruption of the CC ligaments created significant deformity of the GPA and instability with a medial-izing force. Clinical treatment should consider the integrity of these ligaments and their repair in conjunction with clavicle fixation, knowing that this combination should restore a biomechanical state equivalent to an isolated scapula fracture.Level of evidence: Basic Science Study; Biomechanics (c) 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. All rights reserved.

ObjectiveTo validate shear wave elastography (SWE) stiffness measurements for the ulnar collateral ligament (UCL) of the elbow compared to mechanical measurements.Materials and methodsEleven fresh frozen human cadaveric upper extremities were evaluated by a musculoskeletal-specialized radiologist to provide SWE measurements used to calculate stiffness at 4 points along the anterior band of the UCL at various load states and flexion angles. Specimens were then dissected and optical markers were placed on the UCL to track displacement during applied force by a load frame, thereby providing measurements to calculate the mechanical stiffness. These two stiffness values were compared by ANOVA for all load states and flexion angles.ResultsMeasurements of stiffness by SWE for the UCL were three orders of magnitude smaller than the true mechanical testing stiffness and no correlations between SWE and mechanical measurements of stiffness were found at 30, 60 or 90 degrees of elbow flexion (R-2 = 0.004, p = 0.85; R-2 = 0.001, p = 0.92; R-2 = 0.15, p = 0.24 respectively). SWE stiffness was greatest near the insertion of the ligament and lowest in the mid-substance of the ligament (p = 0.0002).ConclusionsSWE stiffness did not correlate with mechanical measurements. Clinical utility of musculoskeletal SWE may be better defined when biomechanical properties or clinical outcomes can be correlated with SWE measurements. The ultimate clinical utility of SWE in musculoskeletal tissues may be qualitative, as demonstrated by differences throughout the length of the UCL in this study.

Background: The inherent nature of the torque-velocity relationship is the inverse nature between the velocity of muscle contraction and torque production and is an indication of muscle function. The purpose of this study was to characterize the torque-velocity relationship in the quadriceps following anterior cruciate ligament recon-struction compared to healthy limbs.Methods: 681 participants were included, 493 of which were patients at least four months following anterior cruciate ligament reconstruction (23.2 & PLUSMN; 10.08 yr, 6.6 & PLUSMN; 5.37 months post-surgery) and 188 were healthy participants (21.6 & PLUSMN; 3.77 yr). A subset of 175 post-surgical participants completed a repeated visit (8.1 & PLUSMN; 1.71 months post-surgery). Participants completed isokinetic knee extension at 90 degrees /s and 180 degrees /s. A one-way ANOVA was used to compare torque velocity relationships by limb type (surgical, contralateral, healthy). Paired samples t-tests were conducted to analyze the torque-velocity relationship across limbs and across time.Findings: There was a large effect for limb type on torque-velocity (F(2, 1173) = 146.08, p < 0.001, & eta;2 = 0.20). Surgical limbs demonstrated significantly lower torque-velocity relationships compared to the contralateral limbs (ACLR: 0.26 Nm/kg, contralateral:0.55 Nm/kg, p < 0.001, d = 1.18). Healthy limbs had similar torque-velocity relationships bilaterally (dominant limb: 0.48 Nm/kg, non-dominant limb: 0.49 Nm/kg, p = 0.45). The torque velocity relationship for the involved limb significantly increased in magnitude over time (+0.11 Nm/kg, p < 0.001, d =-0.61) while the contralateral limb torque-velocity relationship remained stable over time (0.0 Nm/kg difference, p = 0.60).Interpretation: Following surgery, the knee extensors appear to have altered torque-velocity relationships compared to contralateral and healthy limbs. This may indicate a specific target for assessment and rehabilitation following surgery.

Enhanced proficiency for commercial pilots operating in advanced digital technology flight operations is needed to address potential deficits in cognitive resilience. Cognitive resilience is needed when cognitive flow is disrupted or when unanticipated situations occur resulting in cognitive overload or confusion. The researchers propose adding a Digital Flight Deck Management tenet to the current Crew Resource and Threat Error Management model that would focus on successful responses to disruptive effects from computer information and automation operations. The researchers analysed these effects via three approaches. First, a human factors analysis applied an upgraded SHELL model to identify issues that affect cognition, situational awareness, and decision making. Second, evaluating data extracted from NTSB accident reports and ASRS GPS databases, an aviation safety analysis showed the commercial flight industry has become safer, but incidents involving computer information and automation error have increased by as much as 72%. Third, recent trends were examined to assess potential threats in the form of cyber-attacks, digital interference and loss of digital systems that affect digital flight operations. Movement toward efficiency gains are driving forces for increased use of digital information and automation. When considering the evolution and transition of the human-machine collaboration on the digital flight deck, and development of single pilot operations or distributed crewing for commercial flight, the researchers propose augmenting the CRM/TEM model by incorporating a Digital Flight Deck Management tenet to address potential deficits in cognitive resilience, situational awareness, and decision making.

Background The anconeus is a small muscle located on the posterior elbow originating on the lateral epicondyle and inserting onto the proximal-lateral ulna that functions as an elbow extensor as well as dynamic stabilizer. The blood supply is tri-fold: medial/middle collateral artery (MCA), recurrent posterior interosseous artery (RPIA), and less commonly found, the posterior branch of the radial collateral artery. The anconeus has become a popular option for local soft tissue coverage about the elbow (distal triceps, olecranon, proximal forearm). The average defect size for consideration of local anconeus flap coverage is 5–7cm 2 . The aim of the study was to determine safe dissection parameters of the anconeus as well as map arterial pedicles to achieve successful local harvest of the muscle without devascularization. Materials and Methods 8 fresh frozen cadaveric arms (all male, average age 63 years – 4 left arms, 4 right arms) from scapula to fingertip were obtained. First, the radial, ulnar and axillary arteries were dissected and isolated. The radial and ulnar arteries were transected. 100cc normal saline was injected through the axillary artery, sequentially clamping the radial followed by the ulnar artery so that adequate flow could be seen through all vessels. 100cc mixture of Biodür and hardener (10:1) was mixed and injected into the axillary artery. We first allowed free flow through both the ulnar and radial vessels followed by clamping of these vessels. This allowed the pressure to build up and fill the smaller vessels in the arms. After injection, the axillary artery was then clamped and the specimens were left to harden for 24–48 h. After hardening, dissection was performed by making a curvilinear incision centred over the lateral epicondyle. The anconeus was identified and the interval between the anconeus and ECU was then confirmed. Measurements of the anconeus muscle were taken. Blunt dissection was carried between anconeus and ECU until the RPIA was identified and protected. We isolated the MCA by dissecting proximally. This was found to run with the nerve to the anconeus. Once this vessel had been protected, the muscle reflected from distal to proximal staying along its ulnar border. The branches of the RPIA were ligated and the dissection was continued proximally. Measurements of the distances of the RPIA, MCA were taken. Results The average distance of olecranon to muscle tip was 95.0mm. The average distance of lateral epicondyle (LE) to muscle tip was 90.8mm. The average distance of LE to olecranon was 49.8mm. The average location of the RPIA was 63.mm when measuring LE to vessel, 68.3mm when measuring olecranon to vessel, 18.3mm when measuring RPIA to muscle tip. The average RPIA diameter was 1.1mm and length was 36.4mm from the initial branching of the posterior interosseous artery. The average MCA diameter was 0.7mm. The posterior branch of the radial collateral artery was only found in 3/8 specimens. The RPIA and MCA were constant in all specimens. Dissection was safely carried to the border of the LE and olecranon without disruption of the MCA. CONCLUSIONS Our conclusions determined that if dissection of the anconeus is undertaken, the RPIA remains constant between the interval of the ECU as well as anconeus at an average distance of 18.3mm from the tip of the muscle measuring proximally; moreover, the MCA was constant in all specimens found directly between the LE and olecranon always running with the nerve to the anconeus. When dissecting and mobilizing to ensure preservation of the MCA, dissection should be taken from distal to proximal as well as dissecting along the ulnar border of the anconeus. Proximal dissection can be taken as proximal as the border of the LE and olecranon as that did not disrupt MCA blood supply.

BACKGROUND:The use of weightbearing images to diagnose foot and ankle injuries continues to offer hope for improved insight into pathologies, but weightbearing CT imaging has been limited by availability. The ability to apply force to the lower limb in a horizontal bore CT system may offer an adaptation to currently available imaging systems that provides access to weightbearing images without the acquisition of additional expensive imaging space or equipment.METHODS:In order to determine whether a horizontal CT system could produce the same results as a standing CT, 3 images of one foot from 10 subjects was obtained and standard measures were calculated. Each subject underwent a standing CT scan, a scan in a horizontal bore CT machine while the subject pressed against a pedal with spring resistance and a finally a scan with the foot placed on the pedal but without any pressure.RESULTS:No statistically significant difference between the standing and pedal-based CTs resulted. Navicular height and Meary angle (axial) were statistically different from nonweightbearing for both standing and horizontal systems. The horizontal results were statistically different from nonweightbearing in IM angle, talocalcaneal angle, and talonavicular coverage. No differences from nonweightbearing were found for either system in talar tilt, talocrural angle, or the lateral Meary angle.CONCLUSION:The results in this initial study of normal control subjects suggest that a pedal-based loading mechanism may adapt a horizontal-bore CT system for the acquisition of weightbearing images.CLINICAL RELEVANCE:The ability to acquire a weightbearing CT from a horizontal bore CT machine can make these images more available.