Publications by authors named "Jason Koh"

Background: Osteochondral defects (OCDs) in the knee joint have significant clinical implications, particularly regarding contact pressures and pressure distribution. Understanding how these factors are influenced by defect size and location is crucial for developing effective therapeutic strategies.

Purpose/hypothesis: The purpose of this study was to investigate the impact of defect size and location on contact pressures and pressure distribution in the knee joint.

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Introduction: Utilizing large animal model like male pig for biomechanical studies offers a cost-effective approach to understanding human joint and tissue mechanics. Our study explores the osteology and meniscus anatomy of the male porcine stifle joint and compares it to human knee joint parameters, aiming to provide a valuable reference for orthopaedic research and surgical training.

Methods: We examined 60 male porcine stifle joints and analyzed their menisci and bones.

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Purpose: This paper investigates the biomechanical benefits of using hybrid constructs that combine cannulated screws with tension band wiring (TBW) cerclage compared to cannulated screws with anterior Variable Angle locking neutralisation plates (VA LNP). These enhancements can bear heavier loads and maintain the repaired patella's integrity, in contrast to traditional methods.

Method: Eighteen fresh-frozen human cadaver patellae were carefully fractured transversely at their midpoints using a saw.

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Introduction: The escalating incidence of anterior cruciate ligament (ACL) injuries, particularly among adolescents, is a pressing concern. The study of ACL biomechanics in this demographic presents challenges due to the scarcity of cadaveric specimens. This research endeavors to validate the adolescent porcine stifle joint as a fitting model for ACL studies.

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Introduction: The varus and valgus knee deformities result from imbalance in tension between medial and lateral soft tissue compartments. These conditions need to be addressed during total knee arthroplasty (TKA). However, there is no consensus on optimal soft-tissue release techniques for correcting varus and valgus deformities during TKA.

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Orthopedic surgery as a field is the least diverse medical specialty. Multiple factors contribute to the lack of diversity, including lack of diversity in medical school, lack of role models and mentors, and discrimination and bias. Addressing the lack of diversity includes use of data, implementation of targeted pipeline programs, individual physician advocacy, institutional recruitment and DEI initiatives, and leadership from professional organizations.

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Transverse patella fractures, accounting for approximately 1% of Orthopedic injuries, pose intricate challenges due to their vital role in knee mechanics. This study aimed to compare the biomechanical performance of a construct, integrating cannulated screws and an anterior locking neutralization plate, with the conventional tension band wiring technique for treating these fractures. Experimental testing and Finite Element Analysis were employed to evaluate the constructs and gain profound insights into their mechanical behavior.

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Background: Knowledge of acromioclavicular (AC) joint kinematics and distance may provide insight into the biomechanical function and development of new treatment methods. However, accurate data on in vivo AC kinematics and distance between the clavicle and acromion remain unknown.

Purpose/hypothesis: The purpose of this study was to investigate 3-dimensional AC kinematics and distance during arm elevation in abduction, scaption, and forward flexion in a healthy population.

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Given the benefits of patient-reported outcome measure (PROM) implementation and future reporting policies, the PROMs Workgroup conducted a study to evaluate the sentiment and practice patterns related to PROM collection and utilization. A survey including questions regarding sentiment and practice patterns related to PROM importance, collection, and utilization was administered to all members. Data were reported descriptively, and open-ended responses were analyzed using content and frequency analysis.

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Background: This prospective, observational study was designed to assess the phenotype variation of the genes associated with pain and opioid use following total knee arthroplasty (TKA) in comparison to psycho-social elements.

Methods: Preoperative demographic data and Patient-Reported Outcomes Measurement Information System-43 scores were obtained on 305 elective TKA patients. Patient visual analog scale pain scores and opioid use were extracted from the hospital record.

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Aims: The aim of this study was to establish consensus statements on the diagnosis, nonoperative management, and indications, if any, for medial patellofemoral complex (MPFC) repair in patients with patellar instability, using the modified Delphi approach.

Methods: A total of 60 surgeons from 11 countries were invited to develop consensus statements based on their expertise in this area. They were assigned to one of seven working groups defined by subtopics of interest within patellar instability.

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Aims: The aim of this study was to establish consensus statements on medial patellofemoral ligament (MPFL) reconstruction, anteromedialization tibial tubercle osteotomy, trochleoplasty, and rehabilitation and return to sporting activity in patients with patellar instability, using the modified Delphi process.

Methods: This was the second part of a study dealing with these aspects of management in these patients. As in part I, a total of 60 surgeons from 11 countries contributed to the development of consensus statements based on their expertise in this area.

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Introduction: Current clinical practice suggests using patellar and quadriceps tendon autografts with a 10 mm diameter for ACL reconstruction. This can be problematic for patients with smaller body frames. Our study objective was to determine the minimum diameter required for these grafts.

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Objective: To evaluate the effects of liposomal bupivacaine use for interscalene blocks on postoperative analgesia in total shoulder arthroplasty patients.

Methods: De-identified total or reverse total shoulder arthroplasty patients between 2018 and 2021 were analyzed. Patients were grouped into single shot interscalene block with liposomal bupivacaine (LB) with plain bupivacaine, other block (OB) with other local anesthetics (mepivacaine, ropivacaine, or plain bupivacaine), or no block (NB).

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» After transplantation revascularization does occur although data are only available for animal models.» The time zero biomechanics, that is, the biomechanical properties at the time of transplant, of a meniscus allograft transplantation appear to appropriately mimic the original so long as the graft is sized correctly within 10% of the original and bone plug fixation is used.» Allograft type, that is, fresh vs.

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Background: Biomechanical testing of abduction moment arms presents a useful method to assess the contributions of individual rotator cuff muscles to glenohumeral function. This study aimed to investigate the changes in abduction moment arms after the treatment of supraspinatus tears with superior capsular reconstruction (SCR), bursal acromial reconstruction (BAR), and a combined SCR-BAR procedure, all with human dermal allograft.

Methods: We tested 7 fresh-frozen cadaveric specimens under 6 conditions: (1) intact, (2) 50% supraspinatus tear (partial tear), (3) 100% supraspinatus tear, (4) SCR, (5) SCR combined with BAR, and (6) BAR.

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Knee squatting was simulated to characterize the influence of medial patellofemoral ligament (MPFL) reconstruction on patellar tracking and contact pressures for knees with mild patella alta (Caton-Deschamps index = 1.3-1.4).

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Background: Chondral defects in the knee have biomechanical differences because of defect size and location. Prior literature only compares the maximum stress experienced with large defects.

Hypothesis: It was hypothesized that pressure surrounding the chondral defect would increase with size and vary in location, such that a size cutoff exists that suggests surgical intervention.

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Purpose: To provide a biomechanical comparison between human dermal (HD) allograft and long head of biceps tendon (LHBT) autograft with and without posterior side-to-side suturing for superior capsule reconstruction.

Methods: Eight fresh-frozen cadaveric shoulder specimens were tested in 5 conditions: (1) intact, (2) complete supraspinatus tear, (3) LHBT, (4) LHBT with side-to-side suturing, and (5) HD allograft with side-to-side suturing. Functional abduction force, superior translation of humeral head, translational range of motion, and rotational range of motion were tested at 0°, 30°, 60°, and 90° of abduction within each condition.

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Purpose: This study aimed to investigate clinical and radiological results of arthroscopic repair for isolated medial degenerative meniscus tears (DMTs) in patients over 45 years old at a minimum 2-year follow-up.

Methods: From 2013 to 2017, patients aged over 45 years with isolated medial DMT refractory to conservative management or with true mechanical symptoms who had undergone arthroscopic repair were retrospectively reviewed. Arthroscopic meniscus repair was performed using all-inside or all-inside and inside-out technique in combination with bone marrow venting procedure.

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The elderly population experiences a decline in upper extremity range of motion (ROM), impairing activities of daily living. The primary mode of quantification is by goniometer measurement. In this cross-sectional observation study, we investigate a sensor-acquired reachable workspace for assessing shoulder ROM decline in an elderly population in comparison to traditional measurements.

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Introduction: Current understanding of the biomechanical effects of treatment options for irreparable rotator cuff (RC) tears is lacking. This study examines how shoulder muscle lengths and excursions are affected by superior capsular reconstruction (SCR), bursal acromial reconstruction (BAR), and SCR with BAR, following a complete supraspinatus tear.

Method: Six fresh-frozen cadaveric shoulders were examined.

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Background: Distal triceps ruptures are rare, and complete ruptures are commonly treated with surgery. Studies of patients in small cohorts with distal triceps tear have reported outcomes and risk factors; however, large-scale data are scant. This study seeks to determine current trends, outcomes, and risk factors of distal triceps tears.

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