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Objectives: To assess the effects of Krackow suture technique on the vascularity of the patellar tendon., Methods: Six fresh-frozen matched pair cadaveric knee specimens were used. The superficial femoral arteries were cannulated in all knees. The experimental knee underwent an anterior approach, patellar tendon transection from the inferior pole of the patella, 4-strand Krackow stitch placement, patellar tendon repair via 3-bone tunnels, and standard skin closure. The control knee underwent the identical procedure without Krackow stitching. All specimens then underwent precontrast and postcontrast enhanced quantitative magnetic resonance imaging assessment (with gadolinium-based contrast agent). Region of interest analysis was performed to assess for variation in signal enhancement between the experimental and control limbs in various patellar tendon regions and subregions. Latex infusion and anatomical dissection were performed to further evaluate vessel integrity and assess extrinsic vascularity., Results: Quantitative magnetic resonance imaging analysis demonstrated no statistically significant difference in overall arterial contributions. A small but nonsignificant decrease of 7.5% (SD ± 7.1%) in arterial contributions to the entire tendon was observed. Small nonstatistically significant regional decreases throughout the tendon were also detected. In the regional analysis, the largest to smallest decreases in arterial contributions after suture placement were found in the inferomedial, superolateral, lateral, and inferior tendon subregions. In the anatomical dissection, nutrient branches were seen dorsally and posteroinferiorly., Conclusion: The vascularity of the patellar tendon was not significantly affected by Krackow suture placement. Analysis demonstrated small and not statistically significant decreases in arterial contributions, suggesting this technique does not significantly compromise arterial perfusion., Competing Interests: The authors report no conflict of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Treatment of failed total ankle arthroplasty (TAA) is challenging. Limited literature is available on options and outcomes of revision arthroplasty despite failure rates ranging from 10% to 23% within 10 years after primary TAA. This study reports the clinical and radiographic outcomes of revision TAA using a fixed-bearing, intramedullary-referencing implant., Methods: A retrospective review was performed of 18 consecutive revision TAA cases between 2008-2015 using an intramedullary-referencing, fixed-bearing, 2-component total ankle system. Demographic and radiographic data were collected preoperatively, immediately postoperatively, and at the most recent follow-up. Functional outcome data were collected immediately postoperatively and at mean follow-up 47.5 months., Results: Eighteen patients underwent revision TAA, with 77.8% (14/18) implant survival. Index revision was performed most commonly for aseptic talar subsidence (55.6%) or implant loosening (tibia, 29.4%; talus, 58.9%). Following revision, 22.2% (4/18) patients required reoperation at a mean 57.3 (39-86) months. Osteolysis of the tibia, talus, and fibula was present preoperatively in 66.7% (12/18), 38.9% (7/18), and 38.9% (7/18) of patients, respectively, with progression of osteolysis in 27.8% (5/18), 11.1% (2/18) and 11.1% (2/18) of patients, respectively. Subsidence of the tibial and talar revision components was observed in 38.9% (7/18) and 55.6% (10/18) of patients, respectively. The median American Orthopaedic Foot & Ankle Society (AOFAS) score was 74.5 (26-100) and Foot Function Index (FFI) score 10.2 (0-50.4)., Conclusion: Early results of intramedullary-referencing revision TAA demonstrated good patient-reported outcomes with maintenance of radiographic parameters at mean follow-up of 47.5 months. Aseptic talar subsidence or loosening were the main postoperative causes of reoperation. Revision arthroplasty utilizing an intramedullary-referencing implant was a viable option for the failed TAA., Level of Evidence: Level IV, case series.

Surgical management of osteochondral lesions of the talus without an osteotomy depends on the size, location, and chronicity of the lesion. Bone marrow stimulation techniques, such as microfracture, can be performed arthroscopically and have consistently good outcomes in lesions less than 1 cm in diameter. For lesions not amenable to bone marrow stimulation, one-stage techniques, such as allograft cartilage extracellular matrix and allograft juvenile hyaline cartilage, may be used. Arthroscopy may be used in many cases to address these lesions; however, an arthrotomy may be required to use osteochondral autograft and allograft transplantation techniques., Competing Interests: Disclosure M. S. Conti: This author has nothing to disclose. J.K. Ellington: Amniox: paid consultant; Arthrex: IP royalties; Kinos: stock or stock options; Medline: IP royalties, paid consultant, paid presenter or speaker; Medshape: stock or stock options; Nuvasive: paid consultant; Synthes: IP royalties, paid consultant, paid presenter or speaker; Wright Medical Technology: paid consultant. S.B. Behrens: This author has nothing to disclose., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Simvastatin is a common medication prescribed for hypercholesterolemia that accelerates local bone formation. It is unclear whether simvastatin can accelerate healing at the tendon-bone interface after rotator cuff repair. This study was conducted to investigate whether local and systemic administration of simvastatin increased tendon-bone healing of the rotator cuff as detected by maximum load to failure in a controlled animal-based model. Supraspinatus tendon repair was performed on 120 Sprague-Dawley rats. Sixty rats had a polylactic acid membrane overlying the repair site. Of these, 30 contained simvastatin and 30 did not contain medication. Sixty rats underwent repair without a polylactic acid membrane. Of these, 30 received oral simvastatin (25 mg/kg/d) and 30 received a regular diet. At 4 weeks, 5 rats from each group were killed for histologic analysis. At 8 weeks, 5 rats from each group were killed for histologic analysis and the remaining 20 rats were killed for biomechanical analysis. One rat that received oral simvastatin died of muscle necrosis. Average maximum load to failure was 35.2±6.2 N for those receiving oral simvastatin, 36.8±9.0 N for oral control subjects, 39.5±12.8 N for those receiving local simvastatin, and 39.1±9.3 N for control subjects with a polylactic acid membrane. No statistically significant differences were found between any of the 4 groups (P>.05). Qualitative histologic findings showed that all groups showed increased collagen formation and organization at 8 weeks compared with 4 weeks, with no differences between the 4 groups at each time point. The use of systemic and local simvastatin offered no benefit over control groups. [Orthopedics. 2017; 40(2):e288-e292.]., (Copyright 2016, SLACK Incorporated.)

Meniscal injury is a common cause for presentation to the emergency department or primary care physician's office. Meniscal injuries can be the result of a forceful, twisting event in a young athlete's knee or it can insidiously present in the older patient. Many patients with meniscal pathology appropriately undergo conservative management with a primary care physician while some may need referral to an orthopedist for operative intervention. Arthroscopic surgery to address the menisci is the most frequently performed procedure on the knee and one of the most regularly performed surgeries in orthopedic surgery.1 The purpose of this paper is to help elucidate the diagnosis and management of meniscal pathology resulting in knee pain. [Full article available at http://rimed.org/rimedicaljournal-2016-10.asp].

Key Points: The mechanism of therapeutic efficacy of flecainide for catecholaminergic polymorphic ventricular tachycardia (CPVT) is unclear. Model predictions suggest that Na(+) channel effects are insufficient to explain flecainide efficacy in CPVT. This study represents a first step toward predicting therapeutic mechanisms of drug efficacy in the setting of CPVT and then using these mechanisms to guide modelling and simulation to predict alternative drug therapies. Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmia syndrome characterized by fatal ventricular arrhythmias in structurally normal hearts during β-adrenergic stimulation. Current treatment strategies include β-blockade, flecainide and ICD implementation--none of which is fully effective and each comes with associated risk. Recently, flecainide has gained considerable interest in CPVT treatment, but its mechanism of action for therapeutic efficacy is unclear. In this study, we performed in silico mutagenesis to construct a CPVT model and then used a computational modelling and simulation approach to make predictions of drug mechanisms and efficacy in the setting of CPVT. Experiments were carried out to validate model results. Our simulations revealed that Na(+) channel effects are insufficient to explain flecainide efficacy in CPVT. The pure Na(+) channel blocker lidocaine and the antianginal ranolazine were additionally tested and also found to be ineffective. When we tested lower dose combination therapy with flecainide, β-blockade and CaMKII inhibition, our model predicted superior therapeutic efficacy than with flecainide monotherapy. Simulations indicate a polytherapeutic approach may mitigate side-effects and proarrhythmic potential plaguing CPVT pharmacological management today. Importantly, our prediction of a novel polytherapy for CPVT was confirmed experimentally. Our simulations suggest that flecainide therapeutic efficacy in CPVT is unlikely to derive from primary interactions with the Na(+) channel, and benefit may be gained from an alternative multi-drug regimen., (© 2015 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.)

Background: The current clinical standard for the surgical treatment of ankle instability remains the open modified Broström procedure. Modern advents in arthroscopic technology have allowed physicians to perform certain foot and ankle procedures arthroscopically as opposed to traditional open approaches., Methods: Twenty matched lower extremity cadaver specimens were obtained. Steinman pins were inserted into the tibia and talus with 6 sensors affixed to each pin. Specimens were placed in a Telos ankle stress apparatus in an anteroposterior and then lateral position, while a 1.7 N-m load was applied. For each of these tests, movement of the sensors was measured in 3 planes using the Optotrak Computer Navigation System. Changes in position were calculated and compared with the unloaded state. The anteriortalofibular ligament and the calcaneofibular ligament were thereafter sectioned from the fibula. The aforementioned measurements in the loaded and unloaded states were repeated on the specimens. The sectioned ligaments were then repaired using 2 corkscrew anchors. Ten specimens were repaired using a standard open Broström-type repair, while the matched pairs were repaired using an arthroscopic technique. Measurements were repeated and compared using a paired t test., Results: There was a statistically significant difference between the sectioned state and the other 3 states (P < .05). There were no statistically significant differences between the intact state and either the open or arthroscopic state (P > .05). There were no significant differences between the open and arthroscopic repairs with respect to translation and total combined motion during the talar tilt test (P > .05). Statistically significant differences were demonstrated between the 2 methods in 3 specific axes of movement during talar tilt (P = .04)., Conclusion: Biomechanically effective ankle stabilization may be amenable to a minimally invasive approach., Clinical Relevance: A minimally invasive, arthroscopic approach can be considered for treating patients with lateral ankle instability who have failed conservative treatment., (© The Author(s) 2014.)

The aim of this study is to evaluate the mechanical properties of a revision anterior cruciate ligament (ACL) reconstruction after redrilling the original tibial bone tunnel through a retained composite screw compared with initial soft tissue graft fixation. A total of 24 porcine tendons were fixed to porcine tibial tunnels with a 10 × 35 mm composite interference screw. Following the pullout test, a revision tunnel was drilled through the first interference screw and a second graft was fixed in the bone tunnel using a larger composite screw (11 × 35 mm). Following insertion of the revision screw, the graft was reloaded as described for the primary reconstruction. Load versus displacement data were recorded for each test. There were no significant differences between the primary and revision reconstruction constructs for yield load (p = 0.62), linear stiffness (p = 0.18), maximum failure load (p = 0.57), and yield displacement (p = 0.46). These results indicate that the mechanical properties of tibial fixation for ACL reconstruction with a composite screw following a revision provide similar fixation compared with initial reconstruction in this model. Revising a failed composite ACL construct by means of overdrilling and reinstrumenting may provide fixation equivalent to the initial reconstruction., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Posterior sternoclavicular dislocations are rare but serious injuries. The proximity of the medial clavicle to the vital structures of the mediastinum warrants caution with management of the injury. Radiographs are the initial imaging test, though computed tomography and magnetic resonance imaging are essential for diagnosis and preoperative planning. This paper presents an efficient diagnostic approach and effective technique of closed reduction of posterior sternoclavicular dislocations with a brief review of open and closed reduction procedures.

Purpose: To examine the anatomy of the lateral ankle after arthroscopic repair of the lateral ligament complex (anterior talofibular ligament [ATFL] and calcaneofibular ligament [CFL]) with regard to structures at risk., Methods: Ten lower extremity cadaveric specimens were obtained and were screened for gross anatomic defects and pre-existing ankle laxity. The ATFL and CFL were sectioned from the fibula by an open technique. Standard anterolateral and anteromedial arthroscopy portals were made. An additional portal was created 2 cm distal to the anterolateral portal. The articular surface of the fibula was identified, and the ATFL and CFL were freed from the superficial and deeper tissues. Suture anchors were placed in the fibula at the ATFL and CFL origins and were used to repair the origin of the lateral collateral structures. The distance from the suture knot to several local anatomic structures was measured. Measurements were taken by 2 separate observers, and the results were averaged., Results: Several anatomic structures lie in close proximity to the ATFL and CFL sutures. The ATFL sutures entrapped 9 of 55 structures, and no anatomic structures were inadvertently entrapped by the CFL sutures. The proximity of the peroneus tertius and the extensor tendons to the ATFL makes them at highest risk of entrapment, but the proximity of the intermediate branch of the superficial peroneal nerve (when present) is a risk with significant morbidity., Conclusions: Our results indicate that the peroneus tertius and extensor tendons have the highest risk for entrapment and show the smallest mean distances from the anchor knot to the identified structure. Careful attention to these structures, as well as the superficial peroneal nerve, is mandatory to prevent entrapment of tendons and nerves when one is attempting arthroscopic lateral ankle ligament reconstruction., Clinical Relevance: Defining the anatomic location and proximity of the intervening structures adjacent to the lateral ligament complex of the ankle may help clarify the anatomic safe zone through which arthroscopic repair of the lateral ligament complex can be safely performed., (Copyright © 2013 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Background: The traditional Brostrom repair and the modified Brostrom-Gould repair are 2 historically reliable procedures used to address lateral ankle instability. The purpose of this study was to evaluate the biomechanical stability conferred by the Brostrom repair as compared to the Brostrom-Gould modification in an unstable cadaveric ankle model., Methods: A total of 10 cadaveric specimens were placed in a Telos ankle stress apparatus in an anterior-posterior position and then in a lateral position, while a 170 N load was applied to simulate anterior drawer (AD) and talar tilt (TT) tests, respectively. In both circumstances, the ankle was held in 15 degrees of plantarflexion, neutral, and 15 degrees of dorsiflexion, while the movement of the sensors was measured using a video motion analysis system. Measurement of the translation between the talus and tibia in the AD test and the angle between the tibia and talus in the TT test were calculated for specimens in the (1) intact, (2) sectioned (division of the ATFL and CFL), (3) Brostrom repair and (4) Gould modification states., Results: When compared to both the repaired states and the intact states, the sectioned state demonstrated increased inversion and translation at all ankle positions during TT and AD testing. Furthermore, no significant differences were found between the intact state and either of the repaired states. Finally, no difference in the biomechanical stability could be identified between the traditional Brostrom repair and the modified Brostrom-Gould procedure., Conclusions: Our findings indicate that there is no significant biomechanical difference in initial ankle stability conferred by augmenting the traditional Brostrom repair with the Gould modification in this time-zero cadaveric model., Clinical Relevance: These data suggest that the additional reinforcement of an ankle's lateral ligament complex repair of the ankle with the inferior extensor retinaculum may be marginal at the time of surgery.

The objective of this study was to evaluate the mechanical properties of soft-tissue grafts following a single interference screw insertion of 4 different commercially available bioabsorbable interference screws. Twenty-four bovine proximal tibiae (12 matched pairs) were prepared and sagittally split to make 48 bone samples for testing. Tibiae were prepared for a 9 mm porcine tendon graft and were instrumented with 1 of 4 commercially available 10 x 35 mm composite screws, each with a different thread design. The samples were tensile loaded to failure at 200 mm/min and values for yield load, maximum load, and stiffness were recorded to quantify any differences on the function of the grafts. No graft showed macroscopic evidence of laceration following screw insertion and there were no statistically significant differences for yield load (P = .41), maximum load (P = .35), or stiffness (P = .68) among the different screw types. There is no significant difference in the mechanical properties of an anterior cruciate ligament graft following insertion of the 4 bioabsorbable screws tested in this study, in terms of yield load, stiffness, or failure load.

Context: Stress fractures are common injuries in athletes, often difficult to diagnose. A stress fracture is a fatigue-induced fracture of bone caused by repeated applications of stress over time., Evidence Acquisition: PubMed articles published from 1974 to January 2012., Results: Intrinsic and extrinsic factors may predict the risk of stress fractures in athletes, including bone health, training, nutrition, and biomechanical factors. Based on their location, stress fractures may be categorized as low- or high-risk, depending on the likelihood of the injury developing into a complete fracture. Treatment for these injuries varies substantially and must account for the risk level of the fractured bone, the stage of fracture development, and the needs of the patient. High-risk fractures include the anterior tibia, lateral femoral neck, patella, medial malleolus, and femoral head. Low-risk fractures include the posteromedial tibia, fibula, medial femoral shaft, and pelvis. Magnetic resonance is the imaging test of choice for diagnosis., Conclusions: These injuries can lead to substantial lost time from participation. Treatment will vary by fracture location, but most stress fractures will heal with rest and modified weightbearing. Some may require more aggressive intervention, such as prolonged nonweightbearing movement or surgery. Contributing factors should also be addressed prior to return to sports.

Cardiac rhythms arise from electrical activity generated by precisely timed opening and closing of ion channels in individual cardiac myocytes. These impulses spread throughout the cardiac muscle to manifest as electrical waves in the whole heart. Regularity of electrical waves is critically important since they signal the heart muscle to contract, driving the primary function of the heart to act as a pump and deliver blood to the brain and vital organs. When electrical activity goes awry during a cardiac arrhythmia, the pump does not function, the brain does not receive oxygenated blood, and death ensues. For more than 50 years, mathematically based models of cardiac electrical activity have been used to improve understanding of basic mechanisms of normal and abnormal cardiac electrical function. Computer-based modeling approaches to understand cardiac activity are uniquely helpful because they allow for distillation of complex emergent behaviors into the key contributing components underlying them. Here we review the latest advances and novel concepts in the field as they relate to understanding the complex interplay between electrical, mechanical, structural, and genetic mechanisms during arrhythmia development at the level of ion channels, cells, and tissues. We also discuss the latest computational approaches to guiding arrhythmia therapy.

Lateral epicondylitis, or tennis elbow, is the most common cause of elbow pain. This degenerative condition can manifest as an acute process lasting < 3 months or a chronic process often refractory to treatment. Symptom resolution occurs in 70% to 80% of patients within the first year. A "watch-and-wait" approach can be an appropriate treatment option, although physical therapy has been shown to be an effective first-line therapy. Corticosteroids, while providing relief of pain in the acute setting, may be detrimental to recovery in the long term. Platelet-rich plasma injections, although recently well publicized, have not been proven by well-controlled clinical trials to be effective therapy. For patients with symptoms refractory to conservative management, surgical intervention has shown to be a successful treatment modality.

Background: The outcome of rotator cuff repair correlates with tendon healing. Early studies of arthroscopic rotator cuff repair demonstrate lower healing rates than traditional open techniques. Transosseous-equivalent repair techniques (suture bridge) were developed to improve the initial fixation strength., Purpose: To compare the initial in vitro tensile fixation strength of a transosseous-equivalent suture bridge (TOE-SB) rotator cuff repair construct to a traditional transosseous (TO) suture construct., Study Design: Controlled laboratory study., Methods: Identical simulated rotator cuff tears were created on 8 matched pairs of humeri. Each matched pair underwent repair with 4 sutures using either the TOE-SB or TO technique. Initial fixation strength was tested in a custom testing jig. Each shoulder underwent 1000 cycles each of low and then high load testing. Gap displacement was measured at anterior and posterior sites of the repair with digital video tracking of paired reflective markers and recorded at predetermined cycle intervals., Results: There were no statistically significant differences in gap formation at the repair sites under low or high load conditions between TOE-SB and TO techniques. The mean maximal gap formation of the repairs during low load testing in the TOE-SB and TO constructs was 0.93 ± 0.88 mm and 0.55 ± 0.22 mm, respectively (P = .505). The mean maximal gap formation during high load testing in the TOE-SB and TO constructs was 2.04 ± 1.10 mm and 2.28 ± 1.62 mm, respectively (P = .517). The most significant increase in gap distance occurred at the transition from low load to high load in both constructs. Most of the incremental displacement occurred within the first 100 cycles for both high and low load testing (P < .001)., Conclusion: The arthroscopic TOE-SB technique is comparable in initial fixation strength to the traditional TO simple suture repair technique., Clinical Relevance: Arthroscopic techniques can achieve initial fixation strength comparable with traditional TO techniques performed without suture anchors.

Background: Radiographic stress testing using both the anterior drawer (AD) and talar tilt (TT) technique is a widely accepted means of assessing ankle instability. The purpose of this study was to investigate the accuracy of plain film radiography in measuring translation of the talus during the AD test and the rotation of the talus during TT stress testing. In addition to determining the true accuracy of radiologic assessment in two planes, our goal was to further define instability in the sagittal, coronal and transverse planes., Methods: Twenty lower extremity specimens were placed in a Telos ankle stress apparatus, and respective lateral and AP radiographs were taken during simulated AD and TT testing. Positional measurements were calculated from the films. Next, a three-dimensional tracking system was used to calculate these displacements. The anterior talofibular ligament and calcaneofibular ligament were sectioned to simulate an unstable ankle, followed by repeat measurement using both methods. Movement calculated using the three dimensional system was compared to that of plain radiographs using a paired t-test., Results: Mean positional changes determined by plain film radiographs were found to be significantly lower than those calculated by the three-dimensional system in both AD and TT tests in the intact and sectioned states (p < 0.001)., Conclusion: Radiographic stress testing assessment of ankle instability appears to be much less accurate than previously believed., Clinical Relevance: Compared to values calculated with the 3D system, radiographic measurements may underestimate the true magnitude of TT and AD changes which could influence clinical decision making.

Chronic lateral epicondylitis is a common painful condition affecting the elbow. Many treatments have been proposed to alleviate the pain. Surgical treatment options include open, arthroscopic, and percutaneous debridement techniques, while nonoperative modalities have traditionally included physical therapy, bracing, and cortisone injections. Platelet-rich plasma injections have recently gained popularity as an additional treatment option, with early reports of success in elite athletes. The largest study of platelet-rich plasma injections for treatment of lateral epicondylitis showed improvement by platelet-rich plasma compared to corticosteroid injections. This article presents a case of a 55-year-old right-hand-dominant woman with bilateral lateral epicondylitis refractory to multiple corticosteroid injections and physical therapy, treated with platelet-rich plasma injection in the right elbow and concomitant arthroscopic extensor carpi radialis brevis tendon release and debridement in the left elbow. At 4-month follow-up, her visual analog scale was 80/100 in the elbow receiving platelet-rich plasma compared to 10/100 on her operative side, and platelet-rich plasma treatment was considered a failure. The patient then underwent arthroscopic debridement of the right elbow for recalcitrant pain. At 1-year follow-up, both elbows were improved after operative treatment (visual analog scale 10/100 right and 0/100 left), consistent with several studies that have reported improvements from arthroscopic extensor carpi radialis brevis debridement as high as 95%. In our experience, arthroscopic extensor carpi radialis brevis debridement is a safe and efficacious method for treating chronic lateral epicondylitis. Further studies are required to define the role of platelet-rich plasma injections in the treatment of this condition., (Copyright 2011, SLACK Incorporated.)

Internal impingement is a term used to describe the pathologic contact of the undersurface of the rotator cuff with the glenoid. It typically occurs in overhead athletes, particularly throwers. In these athletes, the bones and soft tissues adapt to allow these athletes to have a supraphysiologic range of motion. In many athletes, these changes may lead to symptoms of internal impingement. This article discusses the background, biomechanics, pathophysiology, clinical and radiographic assessment, treatments, and outcomes of this disorder.