Short-term outcomes after primary reverse total shoulder arthroplasty in patients with cervical spine pathology or previous cervical spine surgery compared to those without.

BACKGROUND: Cervical spine (c-spine) and shoulder pathology have been known to cause similar symptoms and often co-exist, making an accurate diagnosis difficult, especially in an elderly population. Reverse total shoulder arthroplasty (rTSA) has been shown to decrease pain and improve quality of life when shoulder pathology is the source of pain and disability. The purpose of this study was to identify the prevalence of c-spine pathology in a cohort of patients who underwent rTSA and to compare postoperative outcome scores to a cohort without c-spine pathology. METHODS: A retrospective review was performed utilizing a single institution's operative records of primary rTSAs. Radiology reports, imaging, and operative reports were reviewed, and presence of any c-spine pathology or previous surgery were recorded. Additionally, postoperative outcome scores (American Shoulder and Elbow Surgeons [ASES], Constant Score, University of California, Los Angeles [UCLA], and Simple Shoulder Test [SST]) were evaluated at >2 years post-rTSA. RESULTS: A total of 438 primary rTSA cases were evaluated. Of these, 143 (32.6%) had documentation of prior c-spine pathology and/or history of previous c-spine surgery. After applying further exclusion criteria, a total of 50 patients with c-spine pathology and 108 patients without c-spine pathology were found to have complete medical records and postoperative outcome scores to allow comparison between groups. Patients without c-spine pathology were found to have statistically higher postoperative UCLA, ASES, and SST scores when compared to patients with c-spine pathology. Patients without c-spine pathology also demonstrated a significant improvement in the difference between their postoperative and preoperative UCLA and ASES scores. CONCLUSION: This study demonstrated a high prevalence of c-spine pathology (32.6%) in a cohort of patients who underwent primary rTSA. Additionally, short-term outcome scores of patients undergoing rTSA with concomitant c-spine pathology are significantly lower than those of patients without a history of c-spine pathology.

Opioid requirements in primary versus revision reverse shoulder arthroplasty.

PURPOSE: The purpose of this study is to evaluate the inpatient pain medication use of patients who had a revision shoulder arthroplasty procedure performed and compare them to a cohort of patients who had a primary reverse total shoulder arthroplasty (rTSA) performed to determine whether revision shoulder arthroplasty requires more pain medication.. METHODS: A retrospective review was performed on patients undergoing revision arthroplasty (n = 75) and primary rTSA (n = 340). Inpatient medication records were reviewed to tabulate the visual analog pain (VAS) all narcotic medication use, and total morphine equivalent units (MEUs) were calculated for the duration of the inpatient stay. RESULTS: There was no significant difference between groups regarding age, sex, body mass index, Charlson Comorbidity Index, American Society of Anesthesiologists score, preoperative narcotic pain medication use, tobacco use, postoperative VAS scores or hospital length of stay. There were no predictors of total postoperative MEUs identified. Overall, patients in the revision arthroplasty group received significantly less total MEUs than those in the primary rTSA group, 134.96 MEUs vs. 69.79 MEUs, respectively (p < .0005). CONCLUSION: The perceived notion that revision shoulder arthroplasty is more painful may cause providers to be more inclined to increase narcotic use, or use more invasive pain control techniques. Based on these data, we found that revision shoulder arthroplasty did not require an increased opioid requirement, longer length of stay or increase VAS, suggesting that these patients can often be managed similarly to primary rTSA.

Routine postoperative laboratory tests are unnecessary after primary reverse shoulder arthroplasty.

BACKGROUND: Obtaining postoperative laboratory studies after primary reverse shoulder arthroplasty (RSA) is a common practice. However, justification of this practice remains unclear. This study assesses the utility of routine postoperative laboratory studies in RSA. METHODS: The electronic medical records of 369 patients who underwent RSA over 10 years were retrospectively reviewed. A total of 213 patients qualified for analysis. Primary outcomes were intervention related to abnormal laboratory values, length of stay, and 90-day emergency department visits/readmissions. Multivariate logistic regression analysis was performed to identify risk factors associated with abnormal laboratory values and postoperative visits/readmissions. RESULTS: Of 213 patients analyzed, 188 (88.7%) had abnormal postoperative laboratory values: 69% had an abnormal hemoglobin (Hgb) or hematocrit level, but only 12% underwent interventions. Lower preoperative Hgb was a significant predictor of receiving a transfusion. A significant association existed between abnormal postoperative electrolyte and creatinine levels with lower body mass index (BMI) and higher Charlson Comorbidity Index (CCI). Only 4 patients (1.8%) received non-transfusion related intervention. Emergency department visits were not statistically different between patients with positive or negative laboratory tests (P = .73). CONCLUSION: Because 87.3% of laboratory studies did not influence patient management, we recommend against routine testing for primary RSA. This study demonstrates that the practice of obtaining routine postoperative laboratory studies is not justified. We recommend selectively obtaining a postoperative basic metabolic profile in patients with increased American Society of Anesthesiologists classification and/or CCI with a lower BMI. We also recommend selectively ordering postoperative complete blood count in patients with a lower preoperative Hgb.

Scapula fracture incidence in reverse total shoulder arthroplasty using screws above or below metaglene central cage: clinical and biomechanical outcomes.

BACKGROUND: Reverse total shoulder arthroplasty (RTSA) is a viable treatment option for rotator cuff tear arthropathy but carries a complication risk of scapular fracture. We hypothesized that using screws above the central glenoid axis for metaglene fixation creates a stress riser contributing to increased scapula fracture incidence. Clinical type III scapular fracture incidence was determined with screw placement correlation: superior screw vs. screws placed exclusively below the glenoid midpoint. Cadaveric RTSA biomechanical modeling was employed to analyze scapular fractures. METHODS: We reviewed 318 single-surgeon single-implant RTSAs with screw correlation to identify type III scapular fractures. Seventeen cadaveric scapula specimens were matched for bone mineral density, metaglenes implanted, and fixation with 2 screw configurations: inferior screws alone (group 1INF) vs. inferior screws with one additional superior screw (group 2SUP). Biomechanical load to failure was analyzed. RESULTS: Of 206 patients, 9 (4.4%) from the superior screw group experienced scapula fractures (type III); 0 fractures (0/112; 0%) were identified in the inferior screw group. Biomechanically, superior screw constructs (group 2SUP) demonstrated significantly (P < .05) lower load to failure (1077 N vs. 1970 N) compared with constructs with no superior screws (group 1INF). There was no significant age or bone mineral density discrepancy. CONCLUSION: Clinical scapular fracture incidence significantly decreased (P < .05) for patients with no screws placed above the central cage compared with patients with superior metaglene screws. Biomechanical modeling demonstrates significant construct compromise when screws are used above the central cage, fracturing at nearly half the ultimate load of the inferior screw constructs. We recommend use of inferior screws, all positioned below the central glenoid axis, unless necessary to stabilize the metaglene construct.

Core decompression and arthroplasty outcomes for atraumatic osteonecrosis of the humeral head.

BACKGROUND: Humeral head osteonecrosis treatment varies depending on the stage and symptoms. Successful outcomes for humeral head core decompression for stage I/II disease in chronic steroid-induced (CSI) osteonecrosis have been reported, but fewer data exist for sickle cell disease (SCD) etiology. Resurfacing and hemiarthroplasty or total shoulder arthroplasty (TSA) are common for advanced collapse, with mixed results. METHODS: We evaluate radiographic and functional outcomes after procedures for humeral head atraumatic avascular necrosis (HAAVN), decompression efficacy in CSI and SCD populations, and report outcomes of advanced disease requiring arthroplasty. Twenty-five shoulders were treated surgically for HAAVN. Post-traumatic AVN patients were excluded. Stage I/II disease received core decompression and ultrasound bone stimulation. Stage III received surface replacement or hemiarthroplasty, and arthroplasty was performed for stage IV/V. Radiographs and clinical scores were recorded preoperatively and postoperatively. RESULTS: Included were 25 HAAVN shoulders (13 SCD and 12 CSI). Eleven shoulders (stage I/II disease) underwent core decompression. Seven of 8 shoulders (88%) progressed to stage III/IV after decompression. All SCD patients progressed to collapse. The procedure in 19 shoulders was surface replacement, hemiarthroplasty, or TSA. Constant, American Shoulder and Elbow Surgeons, Simple Shoulder Test-12, and University of California Los Angeles Shoulder scores were significantly higher at 1- and 2-year follow-up with arthroplasty; 13 of 16 arthroplasty patients (81%) had satisfactory to excellent results. One surface replacement was revised to reverse TSA. CONCLUSIONS: Results suggest core decompression for AVN in SCD patients does not alter osteonecrosis progression and humeral head collapse. Resurfacing and hemiarthroplasty are viable treatment options for stage III, whereas shoulder replacement for stage IV/V disease appears to offer better functional results.

Proximal humeral fractures: pin, plate, or replace.

Proximal humeral fractures are becoming increasingly common in individuals older than 60 years, with only fractures of the hip and distal radius occurring with a higher frequency. Most proximal humeral fractures can be managed without surgery; however, if a fracture is displaced or angulated, surgical treatment may be required. There are four main options for the surgical management of proximal humeral fractures: minimally invasive percutaneous reduction and fixation, open reduction and periarticular plating, hemiarthroplasty, and reverse total shoulder arthroplasty.

Infection after primary anatomic versus primary reverse total shoulder arthroplasty.

BACKGROUND: Deep periprosthetic infection is a serious complication after total shoulder arthroplasty (TSA) and is associated with suboptimal clinical results. This retrospective study aimed to determine whether a difference in infection rate existed after primary anatomic TSA (aTSA) and primary reverse TSA (rTSA). METHODS: A TSA database was retrospectively reviewed to identify primary TSAs performed from 2004 to 2012 and isolate cases of confirmed deep periprosthetic infection. Data collected included age, sex, preoperative diagnosis, previous nonarthroplasty operative history, implant type, and infecting organism. RESULTS: From 814 primary TSAs performed, deep periprosthetic infections were confirmed in 16 shoulders. Infections occurred in 6 aTSAs and 10 rTSAs, with no significant difference among the prosthesis types. Pathogens included Staphylococcus spp, Propionibacterium acnes, and Escherichia coli. In the subgroup of shoulders with no previous operations, no significant difference in infection rate was found among the prosthesis types. Shoulders with previous nonarthroplasty operations undergoing primary TSA exhibited a significantly higher (P = .016) infection rate compared with shoulders with no operative history. Both aTSA and rTSA performed in previously operated-on shoulders demonstrated higher infection rates compared with shoulders with no prior operative intervention. The infection rate was significantly higher (P = .016) in the rTSA group. CONCLUSIONS: There is no difference in infection rate after primary aTSA and primary rTSA in shoulders that have not undergone previous operative interventions. Infection is more likely to develop in shoulders undergoing primary rTSA that have had one or more nonarthroplasty operative procedures.

Biomechanical Evaluation of Recurrent Dissociation of Modular Humeral Prostheses.

The purpose of the study was to evaluate the force and torque required to dissociate a humeral head from the unimplanted modular total shoulder replacement system from different manufacturers and to determine if load and torque to dissociation are reduced in the presence of bodily fluids. Impingement, taper contamination, lack of compressive forces, and interference of taper fixation by the proximal humerus have all been reported as possible causes for dissociation. Experimental values determined in this research were compared with literature estimates of dissociation force of the humeral head under various conditions to gain more understanding of the causes of recurrent dissociations of the humeral head. This study examined biomechanical properties under dry and wet conditions under clinically practiced methods. Mean load to dissociation (1513 N ± 508 N) was found to be greater than that exerted by the activities of daily living (578 N) for all implants studied. The mean torque to dissociation was (49.77 N·m ± 19.07 N·m). Analysis of R2 correlation coefficients and p-values (α = 0.05) did not show any significant correlation between dry/bovine, dry/wet, or wet/bovine for load, displacement, or torsional stiffness in the majority of tests performed. Wetting the taper with water or bovine serum did not reduce the dissociation force to a statistically significant degree. Torque and lack of compressive forces at the rotator cuff may be the cause of dissociation at values less than those of activities of daily living. Torque data are provided by this study, but further research is needed to fully appreciate the role of torque in recurrent dissociations.

Risk factors of instability following reverse total shoulder arthroplasty in patients with no history of shoulder surgery.

Introduction: As its indications expand, reverse total shoulder arthroplasty (rTSA) utilization continues to increase. Though relatively uncommon, instability following rTSA can be associated with significant morbidity and need for subsequent revision and treatment. This case control study aims to characterize factors leading to instability after rTSA, especially in those with no previous shoulder surgery. Methods: 194 rTSAs performed within the study period with appropriate operative indications and follow-up were included. Risk factors used in analysis included age, gender, BMI, ASA class, Charlson comorbidity index (CCI), glenosphere, tray, and liner size. Data was analyzed using a hierarchical binary logistical regression to create a predictive model for instability. Results: Seven patients sustained a post-operative dislocation. Mean time to dislocation was 60.4 weeks. Five required open reduction with placement of either a larger humeral tray or polyethylene spacer. One required open reduction with osteophyte removal, and one was converted to a resection arthroplasty. Dislocators were more likely to have a larger BMI (p = 0.002), higher ASA classification (p = 0.09), and larger liner size (p = 0.01). Conclusion: This study demonstrates a large series of patients successfully treated with rTSA. Dislocations were an uncommon complication, but were clearly associated with higher patient BMI, ASA classification, and increased liner size.

Scapula fractures after reverse total shoulder arthroplasty: classification and treatment.

BACKGROUND: Reverse total shoulder arthroplasty (RTSA) implants have been developed to treat patients with deficient rotator cuffs. The nature of this procedure's complications and how these complications should be managed continues to evolve. Fractures of the scapula after RTSA have been described, but the incidence and best methods of treatment are unclear. QUESTIONS/PURPOSES: We therefore (1) determined the incidence and (2) developed a classification system intended to suggest the best choice of treatment. PATIENTS AND METHODS: We reviewed the records of 400 patients treated with RTSA over 4.5 years and identified all patients with scapula fractures. We identified three discrete patterns: avulsion fractures of the anterior acromion (Type I); fractures of the acromion posterior to the acromioclavicular joint (Type II); and fractures of the scapular spine (Type III). RESULTS: Twenty-two patients (5.5%) had fractures. Eight (2.0%) had Type I fractures on the first followup radiographs; these patients were treated nonoperatively with resolution of symptoms. Ten (2.5%) had Type II fractures a mean of 10.8 months after RTSA; seven of the 10 were treated surgically with improvement in their clinical symptoms. Four (1%) had Type III fractures at a mean of 10.3 months; all four fractures were treated with surgical fixation with healing. CONCLUSIONS: Scapula fracture is a relatively common complication of RTSA. Our observations suggest Type I fractures can be observed with a likelihood of symptom relief. For Type II fractures, we recommend acromioclavicular joint resection if stable but open reduction internal fixation if unstable. We believe Type III fractures are best treated with open reduction internal fixation. LEVEL OF EVIDENCE: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Functional and radiographic long-term outcomes of hemiarthroplasty for proximal humeral fractures.

BACKGROUND: Hemiarthroplasty is the preferred surgical procedure for 3- and 4-part proximal humeral fractures. Our retrospective study examined functional and radiographic outcomes at 2- and 5-year follow-up in patients who received a hemiarthroplasty for 3- and 4-part proximal humeral fractures. MATERIALS AND METHODS: Forty-seven consecutive patients of a single surgeon treated with a cemented shoulder hemiarthroplasty between 2000 and 2006 were followed up. Standard surgical technique was used in all cases. Postoperative radiographs were compared with radiographs at 2 and 5 years along with active range of motion and functional outcomes scores. RESULTS: Twenty-five patients were examined at 2 years and twenty-two at 2 and 5 years. The mean age was 61 years. The mean acromiohumeral distance decreased from 10.3 mm postoperatively to 8.5 mm at 2 years and 6.7 mm at 5 years (P ≤ .001). More patients had stem osteolysis and tuberosity reabsorption at 2 and 5 years compared with postoperatively (P = .016 and P ≤ .001, respectively). The University of California, Los Angeles score decreased from 26.0 to 22.3 (P = .045); the Constant score decreased from 61.1 to 50.1 (P = .01); the Simple Shoulder Test 12 score decreased from 7.7 to 6.2 (P = .018); and the American Shoulder and Elbow Surgeons score decreased from 70.4 to 58.8 (P = .015). Pain scores increased from 2- to 5-year follow-up (P = .018). The range-of-motion measures changed little from the 2-to 5-year follow-up. CONCLUSIONS: Hemiarthroplasty has a high rate of long-term complications. Increases in acromiohumeral distance, stem osteolysis, and tuberosity reabsorption were observed between 2- and 5-year follow-up. Pain scores and functional outcomes worsened. No improvement in range of motion was observed.

Treatment of glenohumeral sepsis with a commercially produced antibiotic-impregnated cement spacer.

BACKGROUND: We report our experience in treating infected shoulder arthroplasty and primary shoulder sepsis using a commercially produced antibiotic-impregnated cement spacer. MATERIALS AND METHODS: We treated 16 shoulders in 15 patients for infected arthroplasty or osteomyelitis of the proximal humerus with irrigation and débridement, hardware removal, or humeral head resection, or both, and placement of an interval articulating hemiarthroplasty with a commercially made gentamicin-impregnated cement spacer. RESULTS: Mean follow-up was 20.5 months after spacer placement. At the time of débridement, 12 shoulders had positive cultures; the most common organisms were methicillin-resistant Staphylococcus aureus (n = 3) and S. epidermidis (n = 3). Twelve patients underwent revision. Four refused revision and have retained antibiotic spacers. White blood cell counts returned to within normal ranges in all patients at the time of revision, the erythrocyte sedimentation rate in 5 of 12 patients, C-reactive protein in 8 of 12 patients, and interleukin-6 in 9 of 11 patients. Mean visual analog pain scale score decreased from 8.4 before spacer placement to 0.5 at the final follow-up. Active forward flexion increased from a mean of 65 degrees to 110 degrees , and active external rotation from -5 degrees to 20 degrees . Mean University of California Los Angeles (UCLA) Shoulder Rating Scale score increased from 7 to 26, Simple Shoulder Test (SST) from 1.2 to 6.6, American Shoulder and Elbow Surgeons (ASES) Standardized Shoulder Assessment Form score from 16 to 74, and Constant score from 16 to 57. There was no recurrence of infection. CONCLUSIONS: Treatment of glenohumeral sepsis with a commercially produced antibiotic-impregnated cement spacer appears to be an effective treatment modality, and serum interleukin-6 level appears to be useful in the evaluation of shoulder infection.

Predicting transfusion in shoulder arthroplasty.

BACKGROUND: This study was conducted to evaluate the incidence of transfusion in shoulder arthroplasty, determine clinical factors associated with increased risk for transfusion, and develop an algorithm to assist the surgeon in preoperative planning with regards to blood management. MATERIAL AND METHODS: The study had 2 phases: (1) development of a clinical prediction rule for transfusion using 280 procedures and (2) a validation study of the algorithm applied to 109 new patients. Phase 1 consisted of a retrospective record review of 280 consecutive shoulder arthroplasties to determine risk factors for transfusion. Phase 1 also identified a preoperative hemoglobin level of less than 12.5 g/dL as predictive of the need for blood transfusion. This cutoff was prospectively applied to 109 patients undergoing shoulder arthroplasty in phase 2. RESULTS: The transfusion rate for phase 1 was 19.6%. Preoperative hemoglobin level (P < .001), age (P= .003), and the number of comorbid conditions (P = .005) were statistically significant risk factors. Patients with a preoperative hemoglobin level of less than 12.5 g/dL have a 4-fold increased risk of requiring a blood transfusion. In phase 2, the cutoff of less than 12.5 g/dL yielded a sensitivity of 88%, specificity of 78%, and positive and negative likelihood ratios of 4.0 and 0.15, respectively. CONCLUSION: Preoperative hemoglobin level, age, and number of comorbid conditions are all predictive of transfusion in shoulder arthroplasty. Tailoring blood ordering based on a preoperative hemoglobin level of 12.5 g/dL is safe and effective. LEVEL OF EVIDENCE: Prognostic study, level 2.

Clinical implications of scapular notching at 2 and 5-year follow-up after reverse total shoulder arthroplasty.

OBJECTIVE: Scapular notching is a unique radiographic sequela of reverse total shoulder arthroplasty (rTSA) with unclear long-term clinical consequences. METHODS: Our retrospective review of a single surgeon, single implant, primary rTSA database investigates the incidence of scapular notching at 2 and 5-year follow-up. Various patient outcome scores were also obtained. RESULTS: Of 158 primary rTSAs performed, 82 (52%) patients completed 2-year and subsequent 5-year follow-up. The incidence of scapular notching at 2 and 5-years was 11.9% and 19.5%, respectively. CONCLUSION: Scapular notching negatively affects validated post-operative outcome scores, active range of motion and total complications, and furthermore increases with time.

Polyethylene Liner Dissociation after Reverse Shoulder Arthroplasty Dislocation: a Case Series.

Reverse shoulder arthroplasty is a common procedure. While dislocation is a common complication, there are few reports documenting dislocation with associated polyethylene liner dissociation from the humeral tray. There have been 4 instances of this occurrence over 9 years at our institution, and there are specific radiographic clues for diagnosis. Recognizing polyethylene liner dissociation on imaging is important prior to treatment. In a "routine" dislocation, closed reduction may be attempted but when the polyethylene is dissociated, open reduction is the only treatment option, as closed reduction can damage the components. Dislocations with polyethylene dissociation may not be initially recognized, prompting a non-operative period leading to wear and metallosis. These 4 cases demonstrate key findings present on imaging to recognize the difference between a dislocation with and without polyethylene liner dissociation, namely the subluxation appearance rather than dislocation.

Tetracycline labeling as a measure of humeral head viability after 3- or 4-part proximal humerus fracture.

HYPOTHESIS: Specifically located humeral head biopsies from three-part proximal humerus fractures taken at the time of hemiarthroplasty will show greater tetracycline labeling under fluorescent microscopy than those biopsies taken from four-part fractures. Additionally, biopsies from younger patients would show greater fluorescence than older patients. MATERIAL AND METHODS: Nineteen consecutive adult patients (range 43-83 years) underwent hemiarthroplasty as definitive treatment for 20 displaced three- and four-part proximal humerus fractures after having received 500 mg of tetracycline hydrochloride orally every six hours for the immediate five preoperative days. Humeral head biopsies were taken from four pre-determined locations intraoperatively. The biopsies were prepared and analyzed with fluorescent microscopy. RESULTS: All specimens in each biopsy location demonstrated fluorescence. There was no difference between the mean rank gray values for the four biopsy locations (p = 0.78 with the Friedman test). There was no difference between the mean rank gray values for the four biopsy locations when analyzed according to three-part vs four-part fracture (p > 0.05 with the Mann-Whitney test). There was an inverse relationship between age and fluorescence for the anterosuperior biopsy location (p = 0.033 with Spearman correlation). DISCUSSION: Vascular supply is preserved in displaced three- and four-part proximal humerus fractures. With intact vascularity to the humeral head, head-preserving techniques utilizing stable, site-specific fixation and minimal dissection should be considered in the treatment of displaced three- and four-part proximal humerus fractures. CONCLUSION: Vascular supply is preserved in displaced three- and four-part proximal humerus fractures, especially in younger patients in the anterosuperior aspect of the humeral head. LEVEL OF EVIDENCE: Basic Science Study.

An evaluation of the relationships between reverse shoulder design parameters and range of motion, impingement, and stability.

BACKGROUND: The purpose of this study was to evaluate the role of reverse shoulder design parameters on performance. METHODS: A computer analysis was conducted on the Grammont reverse shoulder to quantify the effect of varying design parameters on functional measurements during humeral abduction/adduction. To demonstrate the application of these relationships, a novel prosthesis was designed. RESULTS: The Grammont reverse shoulder impinged inferiorly and superiorly on the glenoid at 31 degrees and 95 degrees of humeral abduction with an average jump distance of 10 mm. Several linear relationships were identified. The proposed 38 mm, 42 mm, and 46 mm reverse shoulder designs impinged inferiorly and superiorly on the glenoid at 7.3 degrees/87.5 degrees, 1 degrees/87.5 degrees, and 0 degrees/89.3 degrees of humeral abduction with an average jump distance of 11.7 mm, 13.5 mm, and 14.1 mm, respectively. CONCLUSIONS: The results of this study demonstrate that subtle changes in design parameters can minimize inferior glenoid impingement and offer potential for dramatic functional improvements in ROM (39%) and jump distance (36%).

Fatty infiltration does not progress after rotator cuff repair in a rabbit model.

PURPOSE: The purpose of this study is to evaluate the changes in fatty infiltration of the rotator cuff after it is repaired. METHODS: The supraspinatus muscle was unilaterally detached from the greater tuberosity in 15 New Zealand white rabbits. Six weeks after muscle detachment, 5 rabbits were killed to halt the process of fatty infiltration and 10 rabbits underwent primary repair of the rotator cuff. Six months after repair, the remaining 10 rabbits were killed, and the muscle specimens were examined microscopically to evaluate the muscle with respect to fatty infiltration. RESULTS: Fatty infiltration was evident 6 weeks after detachment of the supraspinatus tendon (P = .0012, analysis of variance). This infiltration was greatest at the musculotendinous junction (P = .0005) and decreased toward the muscle origin (P = .29). Six months after repair of the supraspinatus, there was no progression of fatty infiltration in the repaired muscle as compared with the controls (P = .3). CONCLUSIONS: Fatty infiltration of the rotator cuff in this animal model occurs as early as 6 weeks after a rotator cuff tear. After repair of the rotator cuff, the process of fatty infiltration does not progress any further. The changes that take place in this rabbit model in the first 6 weeks after a rotator cuff tear appear to be irreversible even with successful rotator cuff repair. CLINICAL RELEVANCE: The presence of fatty infiltration of a torn rotator cuff does not preclude a successful repair. The repair can prevent further progression and atrophy of the rotator cuff, but the changes that appear in the muscle as early as 6 weeks after a rotator cuff tear appear to be irreversible.

Biomechanical evaluation of a pre-contoured clavicle plate.

Recent attention has been focused on the operative treatment of mid-shaft fractures of the clavicle. This study compares the in-vitro biomechanical properties of a pre-formed titanium clavicle plate (Acumed) to a Synthes 3.5 mm limited-contact dynamic-compression (LCDC) plate using a cadaveric osteotomy model. An osteotomy was performed on 7 pairs of human clavicles and were randomly plated with either a Synthes 3.5 mm LCDC stainless steel plate or an Acumed titanium pre-contoured clavicle plate. After plating, specimens were tested on an EnduraTEC material testing apparatus for axial compression and tension strength, as well as torsional strength in compression and tension. Biomechanical test results for plated specimens are reported for the LCDC plate and the Acumed plate, and the 2 plates are compared. This exploratory study supports investigations with larger sample sizes to determine if the Acumed pre-contoured plate differs from the LCDC plate in biomechanical properties and the clinical implications of such differences.

Update on Misrepresentation of Research Publications Among Orthopaedic Surgery Residency Applicants.

BACKGROUND: Our 2 previous studies (1999, 2007) examining misrepresentation of research publications among orthopaedic residency applicants revealed rates of misrepresentation of 18.0% and 20.6%, respectively. As the residency selection process has become more competitive, the number of applicants who list publications has increased. The purpose of this study was to determine current rates of research misrepresentation by orthopaedic surgery applicants. METHODS: We reviewed the publication listings and research section of the Common Application Form from the Electronic Residency Application Service (ERAS) for all applicants applying to 1 orthopaedic residency program. The PubMed-MEDLINE database was principally used to search for citations. The PubMed Identifier (PMID) number was used; if no PMID number was listed, a combination of authors or the title of the work was used. If the citations were not found through PubMed, a previously developed algorithm was followed to determine misrepresentation. Misrepresentation was defined as (1) nonauthorship of a published article in which authorship was claimed, (2) claimed authorship of a nonexistent article, or (3) self-promotion to a higher authorship status within a published article. RESULTS: Five hundred and seventy-three applicants applied to our institution for residency in 2016 to 2017: 250 (43.6%) of 573 applicants did not list a publication, whereas 323 (56.4%) of 573 applicants listed ≥1 publication. We found 13 cases of misrepresentation among a total of 1,100 citations (1.18% in 2017 versus 18.0% in 1999 and 20.6% in 2007, p < 0.001). Ten cases of misrepresentation were self-promotion to a higher authorship status. There were 2 cases of claimed authorship of an article that could not be found. Only 1 applicant misrepresented more than once. CONCLUSIONS: Based on our findings, orthopaedic surgery residency applicants are accurately representing their publication information. The incorporation of the PMID number on the ERAS application has streamlined the process for finding publications, and has possibly encouraged veracity on residency applications. Faculty involved in the resident selection process should be aware of the significant decline in the rate of misrepresentation by medical students applying for orthopaedic surgery residency versus the rate in our prior studies.