MRI evaluation of axillary neurovascular bundle: Implications for minimally invasive proximal humerus fracture fixation.

BACKGROUND: Percutaneous fixation of proximal humeral fractures places the axillary nerve and posterior humeral circumflex artery at risk for injury. Safe operative zones for the axillary nerve are described based on external measurements from anatomic landmarks, but no study to date has incorporated advanced imaging to help guide surgical procedures in the region of the axillary neurovascular bundle (ANVB). We sought to define the location and trajectory of the ANVB in relation to osseous landmarks using magnetic resonance imaging (MRI) measurements. METHODS: Retrospective review of 750 consecutive MRI studies was performed with 55 imaging studies meeting inclusion criteria for patient positioning, image alignment, and quality. Five measurements were performed including the distance from mid-lateral acromion to lateral ANVB, mid-lateral acromion to medial ANVB, greater tuberosity to lateral ANVB, vertical distance between inferior anatomic neck and lateral ANVB, and angle the ANVB crosses the humerus. Height, gender, and age were recorded. Analysis was performed using ANOVA and Pearson correlation tests. RESULTS: The lateral ANVB was below the inferior articular margin of the humeral head by an average of 12.9 ± 3.9 mm and within a 22 mm window. It was an average of 57.4 ± 5.1 mm from the lateral mid-acromion, and 34.7 ± 4.3 mm below the greater tuberosity. The angle formed by the ANVB crossing the humerus averaged 19.5 ± 3.9 degrees upward from medial to lateral. Height and gender directly impacted measurements. CONCLUSIONS: The use of the inferior humeral head articular margin provides a radiographic landmark to aid intraoperative lateral ANVB assessment which may be helpful during percutaneous fracture fixation.

Distal clavicle autograft for anterior-inferior glenoid augmentation: A comparative cadaveric anatomic study.

INTRODUCTION: The aim of this study was to anatomically compare distal clavicle and coracoid autografts and their potential to augment anterior-inferior glenoid bone loss. METHODS: Ten millimeters of distal clavicle and 20 mm of coracoid were harvested bilaterally from 32 cadavers. Length, weight, and height were measured and surface area and density were calculated. For each graft, ipsilateral measurements were compared and the ability to restore corresponding glenoid bone loss was calculated. RESULTS: Distal clavicle grafts were larger than coracoid grafts with respect to length (22.3 mm versus 17.7 mm; p < 0.001), height (12.49 mm versus 9.65 mm; p < 0.001), mass (2.72 g versus 2.45 g; p = 0.0437), and volume (2.36 cm3 versus 1.96 cm3; p = 0.002). Coracoid grafts had larger widths (14.56 mm versus 10.52 mm; p < 0.001) and greater density (1.24 g/cm3 versus 1.18 g/cm3; p < 0.001). Distal clavicle surface area was greater on both the articular (2.93 cm2 versus 1.5 cm2; p < 0.001) and superior surfaces (2.76 cm2 versus 1.5 cm2; p < 0.001) when compared to lateral coracoid surface area. DISCUSSION: Distal clavicle grafts were larger and restored larger bony defects but had greater variability and lower density than coracoid grafts. Clinical studies are needed to compare these graft options.

Adoption of Intramedullary Nail Fixation for Proximal Humerus Fractures: Assessment of Surgical Efficiency and Complications.

Fixation of proximal humerus fractures (PHFs) with intramedullary (IM) nails potentially is a newer, less invasive technique. The purpose of this study was to report on the early adoption results of IM nail use for PHF. Retrospective chart reviews were performed on the first 60 patients treated with IM nails for acute PHFs by two shoulder surgeons. The first 15 patients treated by each surgeon were compared with the subsequent 15 patients. Surgical and fluoroscopic times, fracture type, union, and varus collapse were compared. The average operating time decreased (p = .002). Fluoroscopy time, radiographic alignment, union rate, complications, and reoperations were not influenced. Three- and four-part fractures had a higher complication rate than two-part fractures (53% vs. 20%). When considering implementing use of IM nails for treatment of PHFs, initial cases can have outcomes and complications similar to those performed with greater experience. IM nailing appears a good treatment option for two-part PHFs. (Journal of Surgical Orthopaedic Advances 28(2):121-126, 2019).

Psychomotor Testing for Orthopedic Residency Applicants: A Pilot Study.

OBJECTIVE: The purpose of this study was to develop an objective motor skills testing system to aid in the evaluation of potential orthopedic residents. DESIGN: Participants attempted a battery of 5 motor skills tests (4 novel tests and the Grooved Pegboard [GPT] Test) in one 10-minute session. A percentile-based scoring system was created for each test based on raw scores. One-way analysis of variance was used to compare testing scores among 3 cohorts. Each novel test and overall scores were compared with GPT scores as a relative measure of validity. SETTING: The 2015 orthopedic surgery residency interview season at an academic institution. PARTICIPANTS: Thirty orthopedic residents and 72 nonresidents (15 community volunteers and 57 orthopedic surgery residency applicants). RESULTS: Overall, residents performed better than nonresidents (p < 0.0001) and applicants performed worse than residents or volunteers (p < 0.0001). There were positive correlations between the GPT score and overall battery score (r = 0.63), screw and nut test (r = 0.40), and mimic a structure test (r = 0.26). The fracture reduction test and drilling test scores did not correlate to performance on the GPT. CONCLUSIONS: Psychomotor testing for surgical applicants is an area in need of study. This investigation successfully piloted a novel battery of tests, which is easily reproducible and thus may be feasible for use in the orthopedic surgery residency interview setting. Longitudinal evaluation is required to explore correlation with future operative skill.

Abrasiveness of high-strength sutures used in rotator cuff surgery: are they all the same?

BACKGROUND: The suture-tendon interface remains the most common point of failure in rotator cuff repairs via suture pullout. Several high-strength braided sutures are available for rotator cuff surgery and are more abrasive than monofilaments. However, a comparison of these sutures has not been performed in a tissue model. METHODS: Ninety infraspinatus sheep tendons were randomized among 9 groups of sutures (n = 10), including FiberWire (Arthrex, Naples, FL, USA), Collagen Coated FiberWire (Arthrex), Orthocord (DePuy Mitek, Raynham, MA, USA), MaxBraid (Biomet, Warsaw, IN, USA), Force Fiber (Teleflex, Research Triangle Park, NC, USA), ULTRABRAID (Smith & Nephew, Memphis, TN, USA), Phantom Fiber BioFiber (Tornier, Bloomington, MN, USA), and Ti-Cron (Syneture, Mansfield, MA), with Surgipro (Syneture) monofilament as a control. Each suture was cycled 50 times through the tendon, which was fixed to a mechanical testing system under a constant load in saline solution. The distance cut through the tendon was measured and divided by the distance of suture sliding to determine displacement (mm/cm). Twist angle and picks per inch of each suture were measured using digital photography. One-way analysis of variance was used to compare the displacement and twist angle between sutures. RESULTS: Collagen Coated FiberWire was the most abrasive of the high-strength sutures. Four of the sutures (Collagen Coated FiberWire, Phantom Fiber BioFiber, FiberWire, Ti-Cron) had a mean displacement rate greater than 0.150 mm/cm. The remainder of the sutures had a mean displacement rate less than 0.050 mm/cm (Orthocord, Force Fiber, MaxBraid, ULTRABRAID). The difference in the displacement rates between these 2 groups was significant (P < .0001) and was related to both the twist angle and the picks per inch. CONCLUSION: Significant differences in suture abrasiveness were identified among high-strength braided sutures and correlated with lower twist angle and lower picks per inch.