Biomechanical investigation of arm position on deforming muscular forces in proximal humerus fractures.

BACKGROUND: Muscular forces drive proximal humeral fracture deformity, yet it is unknown if arm position can help mitigate such forces. Our hypothesis was that glenohumeral abduction and humeral internal rotation decrease the pull of the supraspinatus and subscapularis muscles, minimizing varus fracture deformity. METHODS: A medial wedge osteotomy was performed in eight cadaveric shoulders to simulate a two-part fracture. The specimens were tested on a custom shoulder testing system. Humeral head varus was measured following physiologic muscle loading at neutral and 20° humeral internal rotation at both 0° and 20° glenohumeral abduction. RESULTS: There was a significant decrease in varus deformity caused by the subscapularis (p<0.05) at 20° abduction. Significantly increasing humeral internal rotation decreased varus deformity caused by the subscapularis (p<0.05) at both abduction angles and that caused by the supraspinatus (p<0.05) and infraspinatus (p<0.05) at 0° abduction only. CONCLUSIONS: Postoperative shoulder abduction and internal rotation can be protective against varus failure following proximal humeral fracture fixation as these positions decrease tension on the supraspinatus and subscapularis muscles. Use of a resting sling that places the shoulder in this position should be considered.

Suture Augmentation Neutralizes Deforming Muscular Forces in a Simulated 2-Part Osteoporotic Proximal Humeral Fracture Model.

OBJECTIVES: To evaluate the contribution that tension-relieving sutures, placed between a proximal humeral locking plate and the rotator cuff muscles, had on preventing varus malalignment in an osteoporotic 2-part proximal humerus fracture model. METHODS: A 2-part fracture model was created in 8 cadaveric specimens and then fixed with a lateral locking plate. A custom shoulder testing system was used to increase loading through the supraspinatus (SS) tendon to drive varus deformity. Trials were performed with no suture placement; SS only; SS and subscapularis (SB); and SS, SB, and infraspinatus. The primary outcome was contribution of each point of suture fixation to prevention of varus collapse. RESULTS: Suture augmentation to the SS, SB, and infraspinatus significantly decreased humeral head varus collapse when compared with the plate alone at nearly all loads ( P < 0.05). There were no significant differences in humeral head varus collapse between the 3 suture constructs. CONCLUSIONS: In our biomechanical evaluation of a simulated osteoporotic 2-part proximal humerus fracture with incompetent medial calcar, tension-relieving sutures placed between a lateral locked plate and the rotator cuff tendons prevented varus malalignment.

Muscular Forces Responsible for Proximal Humeral Deformity After Fracture.

OBJECTIVES: To evaluate the contribution of each of the rotator cuff muscles and deltoid to fracture deformity in a 2-part proximal humerus fracture model. Our hypothesis was that superior cuff muscles would have the greatest contribution to coronal plane deformity, whereas muscles with anterior and posterior attachments would have the greatest contribution to axial and sagittal plane deformity. METHODS: A medial wedge osteotomy was created in 8 cadaveric shoulder specimens. A custom shoulder testing system was used to load each rotator cuff muscle and deltoid under increasing loading conditions. Fracture displacement was measured using a Microscribe digitizing system. The primary outcome was the contribution of each muscle to varus collapse. Secondary outcomes included contributions of each muscle to apex anterior/posterior deformity and humeral head anteversion/retroversion. RESULTS: Unbalanced loading of the supraspinatus resulted in the greatest varus deformity (34.5 ± 2.3 degrees), followed by the infraspinatus (22.3 ± 3.6 degrees) and subscapularis (21.7 ± 3.1 degree) (P < 0.05). Unbalanced loading of the subscapularis induced the greatest apex posterior (27.5 ± 4.8 degrees, P < 0.05) and retroversion (39.0 ± 5.6 degrees, P < 0.05) deformity, whereas the infraspinatus induced the greatest apex anterior (8.7 ± 3.4 degrees, P > 0.05) and anteversion (17.7 ± 5.7 degrees, P > 0.05) deformity. CONCLUSIONS: In this proximal humerus fracture model, the supraspinatus was the primary driver of varus deformity, whereas the subscapularis and infraspinatus contributed to apex posterior/retroversion and apex anterior/anteversion, respectively. The subscapularis and infraspinatus are also important secondary drivers of varus deformity. This study establishes a physiologically relevant fracture model that mimics in vivo conditions for future biomechanical testing.

Biceps Box Configuration for Superior Capsule Reconstruction of the Glenohumeral Joint Decreases Superior Translation but Not to Native Levels in a Biomechanical Study.

PURPOSE: To quantitatively biomechanically assess superior stability, subacromial contact pressures, and glenohumeral kinematics of an in situ biceps tenodesis and a box-shaped long head of the biceps tendon (LHBT) superior capsule reconstruction (SCR) in a superior massive rotator cuff tear (MCT) model. METHODS: Eight cadaveric shoulders (mean age, 62 years; range, 46-70 years) were tested with a custom testing system used to evaluate range of motion, superior translation, and subacromial contact pressure at 0°, 20°, and 40° of abduction. Conditions tested included native state, MCT (complete supraspinatus and one-half of the infraspinatus), a box-shaped LHBT SCR, and an in situ biceps tenodesis. The box-shaped SCR was performed by maintaining the biceps origin, securing 2 corners to the greater tuberosity, and one corner to the posterior glenoid. The in situ tenodesis was performed anatomically at the top of the articular margin in the same shoulder after take-down of the box SCR. RESULTS: Range of motion was not impaired with either repair construct (P > .05). The box SCR decreased superior translation by approximately 2 mm compared with the MCT at 0°, but translation remained greater compared with the intact state in nearly every testing position. The in situ tenodesis had no effect on superior translation. Peak subacromial contact pressure was increased in the MCT at 0° and 20° abduction compared with the native state but not different between the native and box SCR at the same positions. CONCLUSIONS: A box-shaped SCR using the native biceps tendon partially restores increased superior translation and peak subacromial contact pressure due to MCT. The technique may have a role in augmentation of an irreparable MCT. CLINICAL RELEVANCE: The box-shaped LHBT SCR technique may have a role in augmentation of an irreparable MCT.

Major Orthopaedic Conference Abstract Publication: An Analysis of Abstracts Accepted for the AAOS Annual Meetings Between 2014 and 2017.

INTRODUCTION: The American Academy of Orthopaedic Surgeons (AAOS) Annual Meeting provides an opportunity for clinicians to attain the most recent advancements in the orthopaedic field. However, the most recent study analyzing publication rates from the 2001 Annual Meeting determined that only 49% of the podium and poster abstracts were eventually published. The purpose of this study was to determine the publication rate, likelihood of publication based on the presentation format, and time to publication for abstracts presented at the 2014 to 2017 AAOS Annual Meetings. METHODS: We did a comprehensive search of PubMed and Google Scholar to determine whether abstracts presented in the podium, poster, and scientific exhibit formats from the 2014 to 2017 AAOS Annual Meetings were published in a peer-reviewed journal. Abstract title, authors, and keywords were used to query for publication status and date of publication. RESULTS: We analyzed 5,902 abstracts from the 2014 to 2017 AAOS Annual Meetings. The overall publication rate for podium and poster presentations was 69.9%, with individual publication rates at 73.0% and 65.1%, respectively. A higher likelihood of publication in the podium format was noted with odds ratio 1.45 (P < 0.0001). Scientific exhibits displayed a publication rate of 46.9%. Most publications in all formats occurred within 2 years. CONCLUSION: A large increase was noted in the quality of research being presented at the AAOS Annual Meeting. With 69.9% of podium and poster presentations from the 2014 to 2017 Annual Meetings being published in a peer-reviewed journal, clinicians can use the data presented as an up-to-date, adjunct source of guidance for their clinical practices.

Posterior stabilized total knee arthroplasty reproduces natural joint laxity compared to normal in kinematically aligned total knee arthroplasty: a matched pair cadaveric study.

PURPOSE: As the goal of kinematic aligned (KA) total knee arthroplasty (TKA) is to preserve soft tissue tension to the native knee, many KA surgeons recommend cruciate-retaining (CR) prosthesis. However, how a posterior-stabilizing (PS) prosthesis affects the biomechanics of a KA TKA remains unclear. This cadaveric study tested the hypothesis that a PS prosthesis in KA TKA would produce biomechanics similar to CR prosthesis and KA TKA with a PS prosthesis would produce more native knee biomechanics than mechanical aligned (MA) TKA with PA prosthesis. METHODS: Fourteen cadaver knees (7 pairs) were mounted on a knee-testing system to measure knee motion during flexion. For each pair, 1 knee was assigned to KA TKA and the other to MA TKA. In the KA TKA group, the native knee, CR TKA, and PS TKA were tested sequentially. MA TKA was performed using conventional measured resection techniques with a PS prosthesis. All kinematics were measured and compared with the native knee before and after surgery. RESULTS: A PS prosthesis restored femoral rollback similar to a CR prosthesis. CR TKA showed less lateral rollback at knee flexion ≤ 60° than the native knee. There were no differences in soft tissue tensions among the native knee, CR, and PS prosthesis, except in varus tension at 30° of flexion. Varus tension of CR TKA was larger than those of PS TKA and the native knee after KA TKA with < 1 degree difference. Meanwhile, KA TKA achieved knee motion that was closer to the native knee than did MA TKA at ≥ 60° of flexion when using a PS prosthesis. There were no differences in soft tissue tension between KA-PS and MA-PS TKA. CONCLUSIONS: After KA TKA, a PS prosthesis affords similar femoral rollback and soft tissue tension when compared with a CR prosthesis. A PS TKA may be a feasible strategy for patients requiring a PS prosthesis when performing KA TKA. LEVEL OF EVIDENCE: Therapeutic Laboratory study, I.

The utility of a statewide prescription drug-monitoring database vs the Current Opioid Misuse Measure for identifying drug-aberrant behaviors in emergency department patients already on opioids.

BACKGROUND: The most recent guidelines on prescribing opioids from the United States Centers for Disease Control recommend that clinicians not prescribe opioids as first-line therapy for chronic non-cancer pain. If an opioid prescription is considered for a patient already on opioids, prescribers are encouraged to check the statewide prescription drug monitoring database (PDMP). Some additional guidelines recommend screening tools such as the Current Opioid Misuse Measure (COMM) which may also help identify drug-aberrant behaviors. OBJECTIVE: To compare the PDMP and the Current Opioid Misuse Measure (COMM), a commonly-recommended screening tool for patients on opioids, in detecting drug-aberrant behaviors in patients already taking opioids at the time of ED presentation. METHODS: Patients on opioids were enrolled prospectively in a mixed urban-suburban ED seeing approximately 65,000 patients per year. The sensitivity, specificity, likelihood ratios, and diagnostic odds ratios of the PDMP and COMM were compared against objective criteria of drug-aberrant behaviors as documented in the electronic medical record (EMR) and medical examiner databases. RESULTS: Compared to the COMM, the PDMP had similar sensitivity (36% vs 45%) and similar specificity (79% vs 55%), but better positive predictive value, better negative predictive value, and better diagnostic odds ratio. The combination of the PDMP and the COMM did not improve the detection of drug-aberrant behaviors. CONCLUSIONS: The PDMP alone is a more useful as a screening instrument than either the COMM or the combination of the PDMP plus COMM in patients already taking opioids at time of ED presentation. However, the PDMP misses a majority of patients with documented drug-aberrant behaviors in the EMR, and should not be used in isolation to justify whether a particular opioid prescription is appropriate.

Screening Tools Validated in the Outpatient Pain Management Setting Poorly Predict Opioid Misuse in the Emergency Department: A Pilot Study.

BACKGROUND: Currently, no universally accepted methods exist to assess drug-related aberrant behaviors in emergency department (ED) patients. There are several screening tools to identify opioid misuse in patients with chronic pain, however, the validity of these screening tools to assess for misuse within the ED remains unclear. OBJECTIVES: This study investigated the effectiveness of three commonly used screening tools, previously validated in outpatient pain management settings, to assess risk of opioid misuse in ED patients. METHODS: This was a prospective observational study of 154 participants (median age 50 years; 49.6% female) presenting to an academic ED for a chief complaint of pain ≥ 6 months or an opioid refill request. Participants completed the Opioid Risk Tool, the Screener and Opioid Assessment for Patients with Pain-Revised, and the Current Opioid Misuse Measure. Scores for each were compared with electronic medical record (EMR) data alone or a reference standard comprising EMR + statewide prescription drug monitoring program (PDMP) + medical examiner database. RESULTS: Using the combined reference standard, 55.8% of participants displayed at least one aberrant behavior. Regardless of the reference standard, the test characteristics of these screening tools were modest at best, with likelihood ratios close to 1. CONCLUSION: Three screening tools previously validated in outpatient pain management settings poorly categorized risk among ED patients with chronic noncancer pain or requests for opioid refills, and should not be used to assess drug-aberrant behaviors in the ED. Review of the EMR alone or together with the PDMP may be more useful methods to assess drug-aberrant behaviors in the ED setting.

Kinematically aligned total knee arthroplasty reproduces more native rollback and laxity than mechanically aligned total knee arthroplasty: A matched pair cadaveric study.

BACKGROUND: A growing body of evidence supports that kinematically aligned (KA) total knee arthroplasty (TKA) provides superior clinical outcomes and satisfaction than mechanically aligned (MA) TKA. In theory, KA TKA would restore knee kinematics closer to the native condition than MA TKA, but the current biomechanical evidence is lacking. HYPOTHESIS: KA TKA would restore knee biomechanics to the native condition better than MA TKA. METHODS: Seven pairs of cadavers were tested. For each pair, one knee was randomly assigned to KA TKA and the other to MA TKA. During KA TKA, the sizes of femur and tibia resections were equivalent to implant thickness to align with the patient-specific joint line. MA TKA was performed using conventional measured resection techniques. All specimens were mounted on a customized knee-testing system and digitized. Knee motions measured during flexion included rollback, axial tibiofemoral rotation, and laxities, specifically varus-valgus laxity, anterior-posterior translation, and internal-external rotation. RESULTS: The pattern of knee motion following KA TKA was similar to the native knee. However, following MA TKA, both medial and lateral rollback and tibiofemoral axial rotation were decreased relative to those of the native knee. Valgus laxity was restored only after KA TKA, whereas varus laxity was restored only after MA TKA. Anterior translation was increased regardless of the alignment strategy. In addition, rotational laxities were restored after KA TKA, but external rotation laxity increased after MA TKA. CONCLUSION: KA TKA restores femoral rollback and laxity to the native condition better than MA TKA. KA TKA may enhance functional performance and provide a more normal knee sensation. LEVEL OF EVIDENCE: II, Controlled laboratory study.

Factors Associated With Geriatric Frequent Users of Emergency Departments.

STUDY OBJECTIVE: Frequent users of the emergency department (ED) are often associated with increased health care costs. Limited research is devoted to frequent ED use within the increasing senior population, which accounts for the highest use of health care resources. We evaluate patient characteristics and patterns of ED use among geriatric patients. METHODS: This was a multicenter, retrospective, longitudinal, cohort study of ED visits among geriatric patients older than 65 years in 2013 and 2014. Logistic regression analysis was used to identify independent associations with frequent users. The setting was a nonpublic statewide database in California, which includes 326 licensed nonfederal hospitals. We included all geriatric patients within the database who were older than 65 years and had an ED visit in 2014, for a total of 1,259,809 patients with 2,792,219 total ED visits. The main outcome was frequent users, defined as having greater than or equal to 6 ED visits in a 1-year period, starting from their last visit in 2014. RESULTS: Overall, 5.7% of geriatric patients (n=71,449) were identified as frequent users of the ED. They accounted for 21.2% (n=592,407) of all ED visits. The associations of frequent ED use with the largest magnitude were patients with an injury-related visit (odds ratio 3.8; 95% confidence interval 3.8 to 3.9), primary diagnosis of pain (odds ratio 5.5; 95% confidence interval 5.4 to 5.6), and comorbidity index score greater than or equal to 3 (odds ratio 7.2; 95% confidence interval 7.0 to 7.5). CONCLUSION: Geriatric frequent users are likely to have comorbid conditions and be treated for conditions related to pain and injuries. These findings provide evidence to guide future interventions to address these needs that could potentially decrease frequent ED use among geriatric patients.

Kinematically aligned total knee arthroplasty reproduces native patellofemoral biomechanics during deep knee flexion.

PURPOSE: The implant positioning for kinematically aligned total knee arthroplasty (TKA) differs fundamentally from conventional mechanically aligned TKA. This difference may affect patellofemoral (PF) biomechanics after TKA. This cadaveric study tested the hypothesis that kinematically aligned TKA would restore PF biomechanics to the native condition better than mechanically aligned TKA. METHODS: Seven pairs (14 knees) of fresh-frozen cadavers were tested. All specimens were mounted on a customized knee-testing system and digitized using a Microscribe 3DLX instrument (Revware Inc., Raleigh, NC, USA) to measure patellar kinematics in terms of patellar varus/valgus rotation, medial/lateral position, flexion/extension rotation and proximal/distal position at knee flexion angles of 0°, 30°, 60°, 90°, and 120°. The medial and lateral PF joint contact pressure distributions at 120° of knee flexion were measured using a K-scan system (Tekscan Inc., Boston, MA, USA). All patellae remained unresurfaced. For each pair, one knee was randomly assigned to kinematically aligned TKA and the other to mechanically aligned TKA performed using the conventional measured resection technique. During kinematically aligned TKA, the amount of femur and tibia resected was equivalent to implant thickness to maintain the patient-specific joint line. All patellar kinematics were measured and compared between the native condition and after surgery. RESULTS: The patellae of mechanically aligned TKA rotated more valgus and was positioned more laterally compared with those of kinematically aligned TKA at knee flexion angles ≥ 90°. Neither the patellar flexion/extension rotation nor the proximal/distal position differed between either prosthetic knee design and the native knee at all flexion angles. The contact pressure distribution between the medial and lateral PF joint after kinematically aligned TKA were similar to those of the native knee, while the lateral PF joint contact pressure after mechanically aligned TKA was higher than that of the native knee (p = 0.038). CONCLUSIONS: Kinematically aligned TKA better restores patellar kinematics and PF contact pressure distribution to the native condition than mechanically aligned TKA during deep knee flexion. These findings provide clues to understand why kinematically aligned TKA is associated with less anterior knee pain and better PF functional performance compared to mechanically aligned TKA. Patients undergoing kinematically aligned TKA may experience a more normal feeling during deep knee flexion activities.

Suicide screening scales may not adequately predict disposition of suicidal patients from the emergency department.

BACKGROUND: Suicide screening scales have been advocated for use in the ED setting. However, it is currently unknown whether patients classified as low-risk on these scales can be safely discharged from the emergency department. This study evaluated the utility of three commonly-used suicide screening tools in the emergency department to predict ED disposition, with special interest in discharge among low-risk patients. METHODS: This prospective observational study enrolled a convenience sample of patients who answered "yes" to a triage suicidal ideation question in an urban academic emergency department. Patients were administered the weighted modified SADPERSONS Scale, Suicide Assessment Five-step Evaluation and Triage, and Columbia-Suicide Severity Rating Scale. Patients who subsequently received a psychiatric evaluation were included, and the utility of these screening tools to predict disposition was evaluated. RESULTS: 276 subjects completed all three suicide screening tools and were included in data analyses. Eighty-two patients (30%) were admitted or transferred. Three patients (1%) died by suicide within one year of enrollment; one was hospitalized at the end of his or her enrollment visit, dying by suicide seven months later and the other two were discharged, dying by suicide nine and ten months later, respectively. The screening tools exhibited modest negative predictive values (range: 0.66-0.73). CONCLUSION: Three suicide screening tools displayed modest ability to predict the disposition of patients who presented to an emergency department with suicidal ideation. This study supports the current ACEP clinical policy on psychiatric patients which states that screening tools should not be used in isolation to guide disposition decisions of suicidal patients from the ED.

Health Care Usage and Suicide Risk Screening within 1 Year of Suicide Death.

BACKGROUND: Research indicates patients often seek medical care within 1 year of suicide. Health care encounters are a crucial opportunity for health professionals to identify patients at highest risk and provide preventative services. OBJECTIVE: Study aims were to determine the characteristics of persons seeking health care within 12 months of suicide death and evaluate suicide risk screening (SRS) frequency in the emergency department (ED) vs. clinic settings. METHODS: Medical examiner and hospital data of patients who died by suicide from 2007 to 2013 were evaluated. Descriptive analyses included demographics and frequency of ED vs. clinic visits. We also compared SRS before and after implementation of The Joint Commission's recommendation to assess suicide risk. RESULTS: The 224 deceased patients were primarily single white males (mean age 67 years). Mental health issues, substance abuse, and prior suicide attempts were present alone or in combination in 74%. Visits were primarily behavioral health or substance abuse problems in the ED, and medical issues in the clinic. After implementation of universal SRS in the ED, screening increased from 39% to 92%. Among patients screened in the ED, 73% (37 of 51) screened negative for suicide risk. CONCLUSIONS: Universal SRS increased the number of people screened in the ED. However, negative SRS may not equate to reduced risk for future suicide within 1 year. Future studies might investigate targeted screening of individuals with known suicide risk factors, as well as alternatives to patient self-report of intent to self-harm for patients with mental health or substance abuse problems.