Background: Blood flow restriction (BFR) training involves low-weight exercises performed under vascular occlusion via an inflatable cuff. For patients who cannot tolerate high-load exercises, BFR training reportedly provides the benefits of high-load regimens, with the advantage of less tissue and joint stress. Hypothesis: Low-load BFR training is safe and efficacious for strengthening muscle groups proximal, distal, and contralateral to tourniquet placement in the lower extremities. Study Design: Randomized controlled trial. Level of Evidence: Level 1. Methods: This was a randomized controlled trial of healthy participants completing a standardized 6-week course of BFR training. Patients were randomized to BFR training on 1 extremity or to a control group. Patients were excluded for cardiac, pulmonary, or hematologic disease; pregnancy; or previous surgery in the extremity. Data collected at baseline and completion included limb circumferences and strength testing. Results: The protocol was completed by 26 patients, providing 16 BFR and 10 control patients (mean patient age, 27 years; 62% female). A statistically greater increase in strength was seen proximal and distal to the BFR tourniquet when compared with both the nontourniquet extremity and the control group ( P < 0.05). Approximately twice the improvement was seen in the BFR group compared with controls. Isokinetic testing showed greater increases in knee extension peak torque (3% vs 11%), total work (6% vs 15%), and average power (4% vs 12%) for the BFR group ( P < 0.04). Limb circumference significantly increased in both the thigh (0.8% vs 3.5%) and the leg (0.4% vs 2.8%) compared with the control group ( P < 0.01). Additionally, a significant increase occurred in thigh girth (0.8% vs 2.3%) and knee extension strength (3% vs 8%) in the nontourniquet BFR extremity compared with the control group ( P < 0.05). There were no reported adverse events. Conclusion: Low-load BFR training led to a greater increase in muscle strength and limb circumference. BFR training had similar strengthening effects on both proximal and distal muscle groups. Gains in the contralateral extremity may corroborate a systemic or crossover effect. Clinical Relevance: BFR training strengthens muscle groups proximal, distal, and contralateral to cuff placement. Patients undergoing therapy for various orthopaedic conditions may benefit from low-load BFR training with the advantage of less tissue stress.

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Background:Several procedures have been proposed to address irreparable rotator cuff (RC) tears with pseudoparalysis. One recently proposed procedure is superior capsular reconstruction (SCR) using a tensor fasciae latae (TFL) autograft.Hypothesis:SCR with a locally available long head of the biceps tendon (LHB) autograft is biomechanically equivalent to SCR using TFL autograft for preventing superior humeral migration and the development of RC arthropathy in patients with irreparable RC tears.Study Design:Controlled laboratory study.Methods:Ten cadaveric shoulders (5 matched pairs) were tested. One shoulder from each pair was randomly assigned to the LHB reconstruction group using our novel technique, while the contralateral side was assigned to the TFL reconstruction group. SCR with a TFL autograft was performed based on previously described techniques. Massive RC tears were created by detachment of the supraspinatus and infraspinatus footprints from the greater tuberosity. The force required to superiorly translate the humerus 1.5 cm was then tested and recorded using a servohydraulic testing machine under 2 conditions: (1) after a massive RC tear and (2) after SCR with either a TFL autograft or an LHB autograft.Results:SCR with an LHB autograft required 393.2% ± 87.9% (P = .029) of the force needed for superior humeral migration in the massive RC tear condition, while SCR with a TFL autograft required 194.0% ± 21.8% (P = .0125). The LHB reconstruction group trended toward a stronger reconstruction when normalized to the torn condition (P = .059).Conclusion:SCR with an LHB autograft is a feasible procedure that is shown to be biomechanically equivalent and potentially even stronger than SCR with a TFL autograft in the prevention of superior humeral migration.Clinical Relevance:This new technique may help to prevent superior humeral migration and the development of RC arthropathy in patients with irreparable RC tears.

Background Osteosynthesis of distal clavicle fractures can be challenging because of comminution, poor bone quality, and deforming forces at the fracture site. A better understanding of regional differences in the bone structure of the distal clavicle is critical to refine fracture fixation strategies, but the variations in BMD and cortical thickness throughout the distal clavicle have not been previously described. Purpose /questions (1) Which distal clavicular regions have the greatest BMD? (2) Which distal clavicular regions have the greatest cortical thickness values? Methods Ten distal clavicle specimens were dissected from cadaveric shoulders. Eight specimens were female and two were male, with a mean (range) age of 63 years (59 to 67). The specimens were selected to match known epidemiology, as distal clavicular fractures occur more commonly in older patients with osteoporotic bone, and clavicular fractures in older patients are more common in females than males. The clavicles were then imaged using quantitative micro-CT to create 3-D images. The BMD and cortical thickness were calculated for 10 regions of interest in each specimen. These regions were selected to represent locations where distal clavicular fractures commonly occur and locations of likely bony comminution. Findings were compared between different regions using repeated measures ANOVA with Geiser-Greenhouse correction, followed by Bonferroni method multiple comparison testing. Effect size was also calculated to estimate the magnitude of difference between regions. Results The four most medial regions of the distal clavicle contained the greatest BMD (anterior intertubercle space 887 ± 31 mgHA/cc, posterior intertubercle space 879 ± 26 mgHA/cc, anterior conoid tubercle 900 ± 21 mgHA/cc, posterior conoid tubercle 896 ± 27 mgHA/cc), while the four most lateral regions contained the least BMD (anterior lateral distal clavicle 804 ± 32 mgHA/cc, posterior lateral distal clavicle 800 ± 38 mgHA/cc, anterior medial distal clavicle 815 ± 27 mgHA/cc, posterior medial distal clavicle 795 ± 26 mgHA/cc). All four most medial regions had greater BMD than the four most lateral regions, with p < 0.001 for all comparisons. For the BMD ANOVA, η2 was determined to be 0.81, representing a large effect size. The four most medial regions of the distal clavicle also had the greatest cortical thickness (anterior intertubercle space 0.7 ± 0.2 mm, posterior intertubercle space 0.7 ± 0.3 mm, anterior conoid tubercle 0.9 ± 0.2 mm, posterior conoid tubercle 0.7 ± 0.2 mm), while the four most lateral regions had the smallest cortical thickness (anterior lateral distal clavicle 0.2 ± 0.1 mm, posterior lateral distal clavicle 0.2 ± 0.1 mm, anterior medial distal clavicle 0.3 ± 0.1 mm, posterior medial distal clavicle 0.2 ± 0.1 mm). All four most medial regions had greater cortical thickness than the four most lateral regions, with p < 0.001 for all comparisons. For the cortical thickness ANOVA, η2 was determined to be 0.80, representing a large effect size. No differences in BMDs and cortical thicknesses were found between anterior and posterior regions of interest in any given area. Conclusions In the distal clavicle, BMD and cortical thickness are greatest in the conoid tubercle and intertubercle space. When compared with clavicular regions lateral to the trapezoid tubercle, the BMD and cortical thickness of the conoid tubercle and intertubercle space were increased, with a large magnitude of difference. Clinical Relevance Distal clavicular fractures are prone to comminution and modern treatment strategies have centered on the use of locking plate technology and/or suspensory fixation between the coracoid and the clavicle. However, screw pullout or cortical button pull through are known complications of locking plate and suspensory fixation, respectively. Therefore, it seems intuitive that implant placement during internal fixation of distal clavicle fractures should take advantage of the best-available bone. Although osteosynthesis was not directly studied, our study suggests that the best screw purchase in the distal clavicle is available in the areas of the conoid tubercle and intertubercle space, as these areas had the best bone quality. Targeting these areas during implant fixation would likely reduce implant failure and strengthen fixation. Future studies should build on our findings to determine if osteosynthesis of distal clavicular fractures with targeted screw purchase or cortical button placement in the conoid tubercle and intertubercle space increase fixation strength and decreases construct failure. Furthermore, our findings provide consideration for novel distal clavicular locking plate designs with modified screw trajectories or refined surgical techniques with suspensory fixation implants to reliably capture these areas of greatest bone quality.