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Background: Patient-specific instrumentation (PSI) systems for total shoulder arthroplasty (TSA) can improve glenoid component placement, but may involve considerable expense and production delays. The purpose of this study was to evaluate a novel technique for in-house production of 3-dimensionally printed, patient-specific glenoid guides. We hypothesized that our PSI guide would improve the accuracy of glenoid guide pin placement compared with a standard TSA guide., Methods: We randomized 20 cadaveric shoulders to receive pin placement via the PSI guide (n = 10, study group) or standard TSA guide (n = 10, control group). PSI guides were designed to fit each glenoid based on 3-dimensional scapular models constructed from computed tomography scans. A presurgical plan was created for the guide pin trajectory in neutral version and inclination based on individual scapular anatomy. After pin placement, 3-dimensional models from repeated computed tomography scans were superimposed to calculate deviation from the presurgical plan for each specimen., Results: Inclination deviation was significantly lower in the PSI group than in the standard guide group (1.5° ± 1.6° vs. 6.4° ± 5.0°, P  = .009). The glenoid entry site exhibited significantly less deviation in the PSI group (0.8 ± 0.6 mm vs. 2.1 ± 1.2 mm, P  = .008). The average production cost and time for the PSI guides were $29.95 and 4 hours 40 minutes per guide, respectively., Conclusions: The PSI guide significantly improved the accuracy of glenoid pin placement compared with the standard TSA guide. Our PSI guides can be produced in-house, inexpensively, and with substantially reduced time compared with commercially available guides.

The Kuiper Belt is a distant region of the outer Solar System. On 1 January 2019, the New Horizons spacecraft flew close to (486958) 2014 MU 69 , a cold classical Kuiper Belt object approximately 30 kilometers in diameter. Such objects have never been substantially heated by the Sun and are therefore well preserved since their formation. We describe initial results from these encounter observations. MU 69 is a bilobed contact binary with a flattened shape, discrete geological units, and noticeable albedo heterogeneity. However, there is little surface color or compositional heterogeneity. No evidence for satellites, rings or other dust structures, a gas coma, or solar wind interactions was detected. MU 69 's origin appears consistent with pebble cloud collapse followed by a low-velocity merger of its two lobes., (Copyright © 2019 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Background: The purpose of this study was to describe the rate and type of complications occurring within 90 days following the Latarjet procedure for anterior glenohumeral instability., Methods: Consecutive patients undergoing the Latarjet procedure by fellowship-trained surgeons from a single institution between 2007 and 2016 were included for analysis. Indications for the Latarjet procedure included primary or recurrent anterior instability with clinically significant anterior glenoid bone loss and/or failed prior arthroscopic stabilization. Patients undergoing the Latarjet procedure after prior glenoid bone grafting were excluded. All complications that occurred within 90 days of surgery were analyzed and correlated with demographic factors., Results: A total of 146 consecutive patients (146 shoulders) were included. Of these patients, 11 were lost to follow-up and 2 were excluded for having undergone prior open bone grafting. Among the remaining 133 patients (average age, 28.5 ± 11.8 years; 75% male patients), 10 total complications occurred within 90 days of surgery, for an overall short-term complication rate of 7.5%. Of these 10 complications, 6 required subsequent surgery, with recurrent instability in 2 cases (overall rate, 1.50%), infection in 2 (overall rate, 1.50%), musculocutaneous nerve palsy in 1 (overall rate, 0.75%), and postoperative pain in 1 (overall rate, 0.75%). The remaining 4 complications were transient, resolving with nonoperative treatment. No cases of hardware failure or graft osteolysis were reported., Conclusions: The overall 90-day complication rate following the Latarjet procedure for anterior shoulder stabilization was 7.5%. In 6 of the 10 cases, complications led to subsequent surgery, including recurrent instability in 2, while in the remaining 4 cases, the complications were transient and resolved with nonoperative treatment., (Copyright © 2018. Published by Elsevier Inc.)

Purpose: To compare differences in the contour of the anterior and posterior glenoid in 3-dimensional computed tomography reconstructions as a reason for variability in estimating glenoid bone loss., Methods: Three reviewers digitally placed 11 points (1 at 6 o'clock, 5 from 3 to 6 o'clock, and 5 from 6 to 9 o'clock) along the inferior half of glenoid 3-dimensional computed tomography reconstructions of 32 cadaveric specimens. A best-fit circle for the whole glenoid was determined from all 11 points. The anterior 6 points determined an anterior-based circle, as for estimation of posterior bone loss. The posterior 6 points determined a posterior-based circle, as for estimation of anterior bone loss. The area and radii were determined for all circles. Individual intraclass correlations were used to evaluate reliability. Paired t-tests and Wilcoxon signed rank tests were used to compare areas and radii of the anterior and posterior circles relative to the best-fit glenoid circle. Significance was defined as P < .05., Results: There was good-to-excellent inter-rater reliability for the overall best-fit circle (intraclass correlation coefficient [ICC] = 0.97 [95% confidence interval (CI), 0.95-0.99]), anterior circle (ICC = 0.82 [95% CI, 0.71-0.90]), and posterior circle (ICC = 0.78 [95% CI, 0.65-0.88]). The average area of the posterior-based circle was significantly greater than the area of the best-fit circle for the intact glenoid (111% [95% CI, 104.3%-117.7%]; P = .0016). The average radius of the posterior-based circle was significantly larger than the radius of the intact glenoid (105% [95% CI, 101.7%-108.3%]; P = .0042). There were no significant differences between the average area (96% [95% CI, 89.0%-103.0%]; P = .16) and average radius (97% [95% CI, 93.5%-100.5%]; P = .19) for the anterior-based circle relative to the actual whole glenoid., Conclusions: Estimation of anterior glenoid bone loss based on the normal posterior glenoid rim may overestimate glenoid bone loss because of differences in the contour of the anterior and posterior glenoid, whereas estimations of posterior glenoid bone loss based on the anterior rim did not differ significantly from the intact glenoid., Clinical Relevance: A circle based on the remaining intact portion of the injured glenoid may lead to an inaccurate estimate of glenoid bone loss., (Copyright © 2018 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Intramuscular, full-thickness rotator cuff tears are uncommon and present a challenging clinical scenario for repair because traditional suture anchor or transosseous repair techniques are less feasible. The goal of repair is to achieve a tension-free reduction of both ends of the muscle to allow for adequate healing over time. Intramuscular tears of the infraspinatus specifically have rarely been reported. The clinical presentation of these patients can be challenging to interpret, and other causes of rotator cuff dysfunction, including compression to the suprascapular nerve, must be ruled out. In this Technical Note, we describe our technique for arthroscopic side-to-side suture repair of an isolated intramuscular infraspinatus tear.

Biceps tenodesis remains a popular choice for treating anterior shoulder pain in the setting of primary biceps tendinitis or biceps pain due to concomitant glenohumeral joint pathology. A variety of surgical approaches and fixation construct options are available for biceps tenodesis. The advantages of an all-arthroscopic biceps tenodesis include anatomic maintenance of the length-tension relation with strength preservation and improved cosmetic results. This technique can be technically challenging but allows for a minimally invasive approach to anchor the biceps. In this Technical Note, we describe a suprapectoral biceps tenodesis using an all-arthroscopic approach in the setting of concomitant rotator cuff repair. This technique offers a viable alternative to the open subpectoral biceps tenodesis.

Hamstring tendon autograft remains a popular graft choice for anterior cruciate ligament (ACL) reconstruction. Although there are a variety of autograft and allograft options available for ACL reconstruction, advantages of hamstring tendon autografts include decreased postoperative knee pain and an overall easier surgical recovery compared with bone patellar tendon bone autograft. In addition, 4-stranded (quadruple) hamstring grafts are among the strongest grafts biomechanically (at time equals zero). Although the technique of hamstring autograft harvest is relatively straightforward, it is critical to pay attention to several technical steps to avoid iatrogenic neurovascular damage as well as to avoid premature amputation of the graft while using a tendon stripper. In this Technical Note, we describe a technique of hamstring autograft harvest for ACL reconstruction for a quadruple (4-strand) hamstring graft using the gracilis and semitendinosus tendons.

Anterior cruciate ligament reconstruction with bone-patellar tendon-bone autograft has long been considered the graft preference for young, active patients with anterior cruciate ligament injuries. The central-third of the native patellar tendon is a reliable graft and is the preferred option for competitive athletes given its excellent track record with high return-to-play rates and low failure rates. Disadvantages to using this graft include donor site morbidity and associated postoperative anterior knee pain, the risk of patellar fracture or patellar tendon tear, and the potential for graft-construct mismatch. In this Technical Note, we describe our preferred technique for bone-patellar tendon-bone autograft harvest and preparation for anterior cruciate ligament reconstruction.