Publications by authors named "Bong J Jun"
Background: It is unclear if there are significant changes in clinical and radiographic outcomes between 1 and 2 years postoperatively after total shoulder arthroplasty (TSA). The current multi-center study sought to compare patient-reported outcome measures (PROMs), range of motion (ROM) and radiographic analysis of glenoid and humeral loosening between one and two-years postoperatively in a cohort of patients after primary anatomic TSA (aTSA).
Methods: A retrospective cohort of patients who underwent primary anatomic TSA between 2017 and 2018 at two high-volume shoulder arthroplasty centers and had baseline, one and two-year PROMs were included in the study.
Background: The optimal management of posterior glenoid bone loss in glenohumeral osteoarthritis with anatomic total shoulder arthroplasty (aTSA) remains unknown, as the degree of bone loss and retroversion can vary across a wide spectrum in glenoids with Walch B2 and B3 morphology. The objectives of the current study were to evaluate the clinical and radiographic outcomes of utilizing standard, all-polyethylene, nonaugmented anchor-peg glenoid (APG) components in aTSA for patients with mild to moderate B2 or B3 morphology.
Methods: Between January 2010 and September 2019, we identified 79 shoulders with mild to moderate B2 or B3 glenoid morphology that underwent aTSA with use of a nonaugmented APG glenoid component and minimum 2 years clinical and radiographic follow-up.
Objective: To determine whether a simulated low-dose metal artifact reduction (MAR) CT technique is comparable with a clinical dose MAR technique for shoulder arthroplasty evaluation.
Materials And Methods: Two shoulder arthroplasties in cadavers and 25 shoulder arthroplasties in patients were scanned using a clinical dose (140 kVp, 300 qrmAs); cadavers were also scanned at half dose (140 kVp, 150 qrmAs). Images were reconstructed using a MAR CT algorithm at full dose and a noise-insertion algorithm simulating 50% dose reduction.
Purpose: The purpose of the study was to describe the characteristics and demonstrate proof-of-concept and clinical use of a barium sulfate infused polypropylene radiopaque tissue marker for soft tissue localization and in vivo measurement of lengths and areas.
Methods: Marker mechanical properties were evaluated by tensile tests. Biocompatibility was evaluated following 8-12 weeks' implantation in a pig model.
Background: Nonspherical prosthetic humeral head designs have become increasingly popular as they better approximate the native shoulder anatomy and biomechanical properties and is supported by the existing literature. It remains to be seen how this will impact postoperative outcomes for total shoulder arthroplasty providing a justification for this review.
Methods: A review and synthesis of the literature on the subject of joint replacement in the native and prosthetic humeral head was performed.
Background: The primary objectives of this study were to evaluate the ability of a posteriorly stepped augmented glenoid component, used in patients with primary glenohumeral osteoarthritis with B2 or B3 glenoid morphology, to correct preoperative retroversion and humeral head subluxation and to identify factors associated with radiographic radiolucency and patient-reported clinical outcomes.
Methods: We identified 71 shoulders with B2 or B3 glenoid morphology that underwent anatomic total shoulder arthroplasty with use of a posteriorly stepped augmented glenoid component and with a preoperative 3-dimensional computed tomography (3D-CT) scan and a minimum of 2 years of clinical and radiographic follow-up. The Penn Shoulder Score (PSS), shoulder range of motion, glenoid center-peg osteolysis, and postoperative version and humeral head subluxation were the main outcome variables of interest.
Background: Scapular notching is frequently observed following reverse total shoulder arthroplasty (rTSA), although the etiology is not well understood.
Methods: Twenty-nine patients with preoperative computed tomography (CT) scans who underwent rTSA with a Grammont design were evaluated after a minimum of 2 years of follow-up with video motion analysis (VMA), postoperative three-dimensional (3D) CT, and standard radiographs. The glenohumeral range of motion demonstrated by the VMA and the postoperative implant location on the CT were used in custom simulation software to determine areas of osseous impingement between the humeral implant and the scapula and their relationship to scapular notching on postoperative CT.
Background: Walch defined the pathologic characteristics of glenohumeral osteoarthritis on the basis of patterns of glenoid morphology and humeral head subluxation. However, it is unclear how pathologic changes evolve over time. The purpose of this study was to determine whether there are common patterns of pathologic progression based on the Walch classification in primary glenohumeral osteoarthritis and if glenoid bone-loss patterns correlate with rotator cuff fatty infiltration.
View Article and Find Full Text PDFBackground: Inconsistent tension distribution may decrease the biomechanical properties of the rotator cuff tendon after double-row repair, resulting in repair failure. The purpose of this study was to compare the tension distribution along the repaired rotator cuff tendon among three double-row repair techniques.
Methods: In each of 42 fresh-frozen porcine shoulders, a simulated infraspinatus tendon tear was repaired by using 1 of 3 double-row techniques: (1) conventional double-row repair (no bridging suture); (2) transosseous-equivalent repair (bridging suture alone); and (3) compression double-row repair (which combined conventional double-row and bridging sutures).
Purpose: Estimation of anterior glenoid bone loss is important for surgical decision-making. The purpose of this study was to describe a method for estimating anterior glenoid bone loss.
Methods: Thirty-nine cadaveric glenoids were digitized to obtain glenoid geometry.
Background: A non-spherical humeral head has been shown to influence kinematics and stability of the glenohumeral joint; yet, most prosthetic humeral head components are designed to be a perfect sphere. The effect of humeral head shape on prosthetic joint kinematics after total shoulder arthroplasty is not well understood. We hypothesized that prosthetic joint kinematics during humeral axial rotation is dependent on humeral head shape, regardless of joint conformity.
View Article and Find Full Text PDFBackground: Preoperative quantitative assessment of glenoid bone loss, selection of the glenoid component, and definition of its desired location can be challenging. Placement of the glenoid component in the desired location at the time of surgery is difficult, especially with severe glenoid pathological conditions.
Methods: Forty-six patients were randomly assigned to three-dimensional computed tomographic preoperative templating with either standard instrumentation or with patient-specific instrumentation and were compared with a nonrandomized group of seventeen patients with two-dimensional imaging and standard instrumentation used as historical controls.
Purpose: The purpose of this study was to define the subscapularis tendon footprint anatomy in 3-dimensional (3D) perspective, report the incidence of tears, and classify the tear patterns prospectively during shoulder arthroscopic surgery.
Methods: The cadaveric study consisted of a pilot study that revealed 4 different bony facets by simple observation at the subscapularis attachment. The 3D footprint anatomy was digitally evaluated in 39 cadavers.
Background: With the advent of arthroscopy, more partial subscapularis tears are being recognized. The biomechanical effects of partial subscapularis tears are unknown, and there is no consensus as to their treatment. Therefore, the objective of this study was to evaluate and to quantify the changes in range of motion and glenohumeral kinematics for isolated subscapularis partial tears, combined subscapularis and supraspinatus tears, supraspinatus repair, and combined supraspinatus and subscapularis repair.
View Article and Find Full Text PDFPurpose: Our purpose was to investigate the effect of supraspinatus tendon tear combined with anterior capsulolabral injury on glenohumeral joint biomechanics and to identify which structures should be repaired when both pathologic conditions are present.
Methods: Eight cadaveric shoulders were tested on a custom system. Five conditions were tested: intact supraspinatus full-thickness tear, supraspinatus tear combined with Bankart lesion, supraspinatus repair, and supraspinatus repair combined with Bankart repair.
Background: The purpose of this study was to quantitatively evaluate the effect of the prosthetic humeral head shape on rotational range of motion and glenohumeral joint kinematics.
Methods: Six fresh-frozen cadaveric shoulders were tested in multiple positions under anatomic muscle loading. Specimens were tested for the native head, and then the spherical and non-spherical prosthetic heads were randomly implanted in the same stem to preserve the center of rotation.
Background: Although deviations in scapular orientation are thought to predispose to shoulder injuries in throwing athletes, the biomechanical mechanism underlying shoulder injuries in throwing athletes with an altered scapular orientation remains unclear.
Methods: Seven fresh-frozen cadaveric shoulders were evaluated at 90° of abduction, with the humerus externally rotated from 90° to the maximum angle, to simulate the late cocking phase of the throwing motion. Loads were applied to the deltoid, pectoralis major, latissimus dorsi, teres major, and all rotator cuff muscles.
Background: Complete repair in massive rotator cuff tear may not be possible, allowing for only partial repair. However, the effect of partial repair on glenohumeral biomechanics has not been evaluated. Therefore, the purpose of this study was to compare the rotational range of motion (ROM), glenohumeral kinematics, and gap formation at the repaired tendon edge following massive cuff tear and repair according to the degree of repair completion.
View Article and Find Full Text PDFPurpose: The purpose of this study was to compare the biomechanical characteristics of a massive L-shaped retracted rotator cuff tear repaired with either soft-tissue side-to-side sutures or margin convergence anchorage to bone.
Methods: Eight matched pairs of cadaveric shoulders were used. The supraspinatus and infraspinatus were secured in a clamp at 30° of glenohumeral abduction.
Background: It is unknown at which stage of rotator cuff tear the biomechanical environment is altered. The purpose of this study was to determine if a critical rotator cuff tear stage exists that alters glenohumeral joint biomechanics throughout the rotational range of shoulder motion, and to evaluate the biomechanical effect of parascapular muscle-loading.
Methods: Eight cadaver shoulders were used with a custom testing system.
Purpose: The optimum number of cross-stitches in modified Becker repair for extensor tendon injury is not known. The purpose of this study was to compare the biomechanical characteristics of 1, 2, and 3 cross-stitches in modified Becker extensor repairs.
Methods: We used 8 fresh-frozen cadaveric hands (24 fingers).
Background: There has been concern regarding the fixation of anterior cruciate ligament reconstruction, with soft tissue grafts being strong and stiff enough to allow for early accelerated postoperative rehabilitation. Therefore, some have recommended supplementary fixation for soft tissue tibia interference screw fixation with a staple, to improve the strength and stiffness of the fixation. Unfortunately, with staple supplementation, there is a risk for symptomatic hardware, which may require a second surgery to remove the staple.
View Article and Find Full Text PDFBackground: After rotator cuff repair, the shoulder is immobilized in various abduction positions. However, there is no consensus on the proper abduction angle.
Purpose: To assess the effect of shoulder abduction angle on the biomechanical properties of the repaired rotator cuff tendons among 3 types of double-row techniques.
Background: A transtendon interimplant mattress repair along the medial row for partial-thickness rotator cuff repairs has been described with clinical success. However, the biomechanical characteristics for such a repair have not been elucidated.
Hypothesis: A knotless interimplant mattress repair may show improved or equivalent load and strain characteristics, compared with a repair using isolated mattress repairs over each of 2 anchors.
Background: Biomechanical testing without humeral motion is a standard method for evaluating rotator cuff repair constructs. This cannot elucidate the effects of dynamic external rotation on the repair, which is a common postoperative motion.
Hypothesis: Biomechanical properties and gap formation of rotator cuff repairs will be different when dynamic external rotation is allowed to occur during loading.