Failure of humeral shaft fixation: construct characteristics.

PURPOSE: Fixation failure following open reduction and internal fixation (ORIF) of humeral shaft fractures can be a challenging complication. We aimed to identify the modes of failure and characteristics of failed fixation constructs. METHODS: We queried our institutional database for patients > 18 years old with fixation failure after ORIF with single plate and screw constructs of humeral shaft fractures from 2006 to 2017. Demographics, fracture characteristics, fixation construct design and mode of failure were recorded. RESULTS: Twenty-three failures were identified. Mean age was 55.9 years (SD 19.2 years) with 15 (65%) women. Twelve patients (52%) had midshaft fractures; the remainder had distal-third shaft (8 pts, 35%) or proximal-third shaft (3 pts, 13%) fractures. Midshaft fractures were most commonly fixed through an anterolateral approach with plates and all non-locking screws (83%), while distal-third shaft fractures were fixed with a combination of locking and non-locking screws from a posterior approach. Distal-third shaft fractures failed by plate breakage (63%) or screw pullout (38%) and all midshaft failures occurred by screw pullout proximal (92%) or distal (8%) to the fracture. Resultant varus deformity occurred in 20 (87%) fractures. CONCLUSION: Screw pullout in midshaft fractures suggests that fixation to bone was insufficient or biomechanically disadvantageous. Varus moments contribute significantly to the failure of humeral shaft fracture ORIF. Plate breakage in distal fractures suggests high concentrations of stress over a narrow working length of constructs with inadequate plate strength. Recognizing how these constructs fail can aid proper implant selection and application for humeral shaft fracture. LEVEL OF EVIDENCE: Treatment level IV.

Defining massive rotator cuff tears: a Delphi consensus study.

BACKGROUND: A standard definition for massive rotator cuff tears (MRCTs) has not been identified. The purpose of this study is to use the modified Delphi technique to determine a practical, consensus definition for MRCTs. METHODS: This study is based on responses from 20 experts who participated in 4 rounds of surveys to determine a consensus definition for MRCT. Consensus was achieved when at least 70% of survey responders rated an item at least a 4 on a 5-point scale. A set of core characteristics was drafted based on literature review and then refined to achieve a consensus MRCT definition. RESULTS: The following core characteristics reached consensus in the first round: tear size, number of tendons torn, and degree of medial retraction. Magnetic resonance imaging (MRI) and intraoperative findings reached consensus as the modalities of diagnosis. The second round determined that tear size should be measured as a relative value. An initial definition for MRCT was proposed in the third round: retraction of tendon(s) to the glenoid rim and/or a tear with ≥67% greater tuberosity exposure (65% approval). A modified definition was proposed that specified that degree of retraction should be measured in the coronal or axial plane and that the amount of greater tuberosity exposure should be measured in the sagittal plane (90% approval). CONCLUSIONS: This study determined with 90% agreement that MRCT should be defined as retraction of tendon(s) to the glenoid rim in either the coronal or axial plane and/or a tear with ≥67% of the greater tuberosity exposed measured in the sagittal plane. The measurement can be performed either with MRI or intraoperatively.

Comparison of Asymmetric Reaming versus a Posteriorly Augmented Component for Posterior Glenoid Wear and Retroversion: A Radiographic Study.

BACKGROUND: Managing posterior glenoid wear and retroversion remains a challenge in shoulder arthroplasty. Correcting glenoid version through asymmetric reaming (AR) with placement of a standard glenoid component and the use of posteriorly augmented glenoid (PAG) components are two methods used to address this problem. Our objective is to report the radiographic outcomes of patients with posterior glenoid wear and/or retroversion treated with either approach. METHODS: Patients with posterior glenoid wear and a minimum of 15 degrees of retroversion, treated with AR and standard glenoid component or with a PAG component (3 mm, 5 mm, or 7 mm posterior augmentation), were consecutively identified through retrospective chart review. Pre-operative axillary views were evaluated for version, humeral head subluxation in relation to scapular axis and to mid-glenoid face. Post-operative axillary views were reviewed to measure corrected inversion and humeral head subluxation. RESULTS: There were 48 patients in the AR group and 49 patients in the PAG group. Version improved 6.8 degrees in the AR group. In the PAG group, version improved 8.8 degrees with 3 mm augment, 13.4 degrees with 5 mm augment, and 12.8 with 7 mm augments. There were significantly more central peg perforations in the 5 mm PAG group compared to other groups. The humeral head was re-centered within 6.1% of normal in all groups except 7 mm augments. CONCLUSION: This study demonstrates that AR and PAGs have the ability to re-center the humeral head when utilized in patients with retroversion and posterior wear. Use of a PAG component may allow for greater correction of glenoid retroversion, however, there is an increased risk for central peg perforation with the specific implant utilized in this study. Long-term follow-up is ongoing and needed to understand the clinical implications of these findings.

Evaluating Glenohumeral Osteoarthritis: The Relative Impact of Patient Age, Activity Level, Symptoms, and Kellgren-Lawrence Grade on Treatment.

BACKGROUND: It is not always clear how to treat glenohumeral osteoarthritis, particularly in young patients. The goals of this study were to 1) quantify how patient age, activity level, symptoms, and radiographic findings impact the decision-making of shoulder specialists and 2) evaluate the observer reliability of the Kellgren-Lawrence (KL) grading system for primary osteoarthritis of the shoulder. METHODS: Twenty-six shoulder surgeons were each sent 54 simulated patient cases. Each patient had a different combination of age, symptoms, activity level, and radiographs. Responders graded the radiographs and chose a treatment (non-operative, arthroscopy, hemiarthroplasty, or total shoulder arthroplasty). Spearman correlations and chi square tests were used to assess the relationship between factors and treatments. Sub-analysis was performed on surgical cases. An intra-class correlation (ICC) was used to assess observer agreement. RESULTS: The significant correlations (P<0.01) were: symptoms [0.46], KL grade [0.44], and age [0.11]. In the sub-analysis of operative cases, the significant correlations were: KL grade [0.64], age [0.39], and activity level [-0.10]. The chi square analysis was significant (P<0.01) for all factors, but the practical significance of activity level was minimal. The ICCs were [inter](intra): KL [0.79] (0.84), patient management [0.54]. CONCLUSION: When evaluating glenohumeral osteoarthritis, patient symptoms and KL grade are the factors most strongly associated with treatment. In operative cases, the factors most strongly associated with the choice of operation were the patient's KL grade and age. Additionally, the KL classification demonstrated excellent observer reliability. However, there was only moderate agreement among shoulder specialists regarding treatment, indicating that this remains a controversial topic.

Biomechanical Assessment of Locking Plate Fixation of Comminuted Proximal Olecranon Fractures.

OBJECTIVES: To determine if mean ultimate strength or failure mechanism differed between comminuted olecranon fractures created at the proximal 25% or 50% of the trochlear notch and fixed with precontoured posterior locking plates (PLPs). METHODS: Comminuted osteotomies were created in 10 matched pairs of cadaveric upper extremities at either the proximal 25% or 50% of the trochlear notch after quantitative computed tomography scans were performed to evaluate bone mineral density. Variable-angle olecranon PLPs were fixed to the specimens. The triceps tendon of each specimen was loaded cyclically and then to failure. Comparison of mean force at failure (displacement >2 mm) was performed using the 2-tailed t test. RESULTS: There were no significant differences in specimen bone mineral density within matched pairs. Nineteen specimens failed by olecranon bisection fracture in the sagittal plane. Specimens in the 25% osteotomy group failed at lower ultimate forces of 808 N (SD ± 474 N) versus 1058 N (SD ± 480 N) in the 50% osteotomy group (P = 0.044). CONCLUSIONS: The ultimate strength of comminuted olecranon fracture fixation with a PLP decreases significantly if the fracture is proximal to the midpoint of the trochlear notch. Fractures proximal to the midpoint of the trochlear notch may benefit from supplemental fixation or suture augmentation to prevent failure, particularly at force ranges higher than those experienced during active elbow range of motion.