Position statement: management of rotator cuff tears in adults.

We sought to compare success and re-tear rates of surgically treated full-thickness tears of the rotator cuff in men and women older than 18 years of age to develop a guideline intended for orthopedic surgeons and other health care providers who assess, counsel and care for these patients. We searched Medline, Embase and Cochrane databases through to Apr. 20, 2021, and included all English-language randomized trials comparing single-row versus double-row fixation via arthroscopic approaches; latissimus dorsi transfer (LDT) versus partial rotator cuff repair, lower trapezius transfer (LTT), and superior capsular reconstruction (SCR); and early versus late arthroscopic rotator cuff repair for traumatic tears. We also considered observational studies comparing LDT with LTT and partial repair and studies comparing early versus late treatment of traumatic rotator cuff tears. Outcomes of interest were functional outcomes, pain outcomes, and re-tear rates associated with these interventions. We rated the quality of the evidence and strength of recommendations using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach. This guideline will benefit patients seeking surgical intervention of full thickness rotator cuff tears by improving counselling on surgical treatment options and outcomes. It will also benefit surgical providers by expanding their knowledge of various surgical approaches. Data presented could be used to develop frameworks and tools for shared decision-making.

Treatment of rotator cuff tears: a systematic review and meta-analysis.

BACKGROUND: There is ongoing controversy regarding optimal treatment for full-thickness rotator cuff tears. Given that the evidence surrounding the use of various treatment options has expanded, an overall assessment is required. OBJECTIVES: The following were compared to determine which resulted in improved patient-reported function, pain, and reoperation rates for each: (1) double-row (DR) fixation and single-row (SR) fixation in arthroscopic cuff repair; (2) latissimus dorsi transfer (LDT) with lower trapezius transfer (LTT), partial rotator cuff repair, and superior capsular reconstruction (SCR); and (3) early and late surgical intervention. METHODS: Medline, Embase, and Cochrane were searched through to April 20, 2021. Additional studies were identified from reviews. The following were included: (1) All English-language randomized controlled trials (RCTs) in patients ≥18 years of age comparing SR and DR fixation, (2) observational studies comparing LDT with LTT, partial repair, and SCR, and (3) observational studies comparing early vs. late treatment of full-thickness rotator cuff tears. RESULTS: A total of 15 RCTs (n = 1096 randomized patients) were included in the meta-analysis of SR vs. DR fixation. No significant standardized mean differences in function (0.08, 95% confidence interval [CI] -0.09, 0.24) or pain (-0.01, 95% CI -0.52, 0.49) were observed. There was a difference in retear rates in favor of DR compared with SR fixation (RR 1.56, 95% CI 1.06, 2.29). Four studies were included in the systematic review of LDT compared with a surgical control. LDT and partial repair did not reveal any differences in function (-1.12, 95% CI -4.02, 1.78) on comparison. A single study compared arthroscopically assisted LDT to LTT and observed a nonstatistical difference in the Constant score of 14.7 (95% CI -4.06, 33.46). A single RCT compared LDT with SCR and revealed a trend toward superiority for the Constant score with SCR with a mean difference of -9.6 (95% CI -19.82, 0.62). Comparison of early vs. late treatment revealed a paucity of comparative studies with varying definitions of "early" and "late" treatment, which made meaningful interpretation of the results difficult. CONCLUSION: DR fixation leads to similar improvement in function and pain compared with SR fixation and results in a higher healing rate. LDT transfer yields results similar to those from partial repair, LTT, and SCR in functional outcomes. Further study is required to determine the optimal timing of treatment and to increase confidence in these findings. Future trials of high methodologic quality comparing LDT with LTT and SCR are required.

A Reliable and Valid Objective Structured Assessment of Technical Skill for the Application of a Pavlik Harness Based on International Expert Consensus.

BACKGROUND: The use of competency-based training is increasing in medical education as it offers individualized learning opportunities to master required skills. Inherent to this method of teaching is the need for standardized and objective assessments of skill mastery. In orthopaedic surgery, educational programs have focused on surgical skills with lesser emphasis on nonoperative techniques. Accordingly, formal evaluation tools specific to Pavlik Harness application do not exist, despite its widespread use and potential complications from inappropriate application. This study sought to develop a reliable and valid evaluation tool based on international expert consensus to standardize and evaluate Pavlik Harness application for developmental dysplasia of the hip. METHODS: Consensus was sought from 10 content experts using Delphi methodology. Resulting items formed the Objective Structured Assessment of Technical Skill (OSATS). Thirty-five participants were selected into 3 a priori groups (expert, intermediate and novice) based on Pavlik Harness experience. On 2 occasions, 3 content experts assessed randomized and deidentified videotapes of each participant applying a Pavlik Harness to an infant model using the OSATS and global rating scales (GRS). The reliability and validity of the OSATS was determined with intraclass (ICC) and Pearson correlations and analysis of variance (ANOVA). RESULTS: Consensus was obtained after 2 rounds of structured surveying and resulted in a 25-item OSATS. The reliability of the OSATS was excellent with an ICC of 0.96 for interrater and 0.98 for test-retest reliability. Construct validity was excellent with high correlations between OSATS and GRS (>0.90). In addition, the OSATS discriminated between expert, intermediate, and novice users. CONCLUSIONS: We have developed a competency-based evaluation tool for Pavlik Harness application based on consensus from international experts. The OSATS has been shown to be a reliable and valid method for assessing Pavlik Harness application that can discriminate between expert, intermediate, and novice users. LEVEL OF EVIDENCE: Level II.

A thiolate anion buried within the hydrocarbon ruler perturbs PagP lipid acyl chain selection.

The Escherichia coli outer membrane phospholipid:lipid A palmitoyltransferase PagP exhibits remarkable selectivity because its binding pocket for lipid acyl chains excludes those differing in length from palmitate by a solitary methylene unit. This narrow detergent-binding hydrophobic pocket buried within the eight-strand antiparallel beta-barrel is known as the hydrocarbon ruler. Gly88 lines the acyl chain binding pocket floor, and its substitution can raise the floor to correspondingly shorten the selected acyl chain. An aromatic exciton interaction between Tyr26 and Trp66 provides an intrinsic spectroscopic probe located immediately adjacent to Gly88. The Gly88Cys PagP enzyme was engineered to function as a dedicated myristoyltransferase, but the mutant enzyme instead selected both myristoyl and pentadecanoyl groups, was devoid of the exciton, and displayed a 21 degrees C reduction in thermal stability. We now demonstrate that the structural perturbation results from a buried thiolate anion attributed to suppression of the Cys sulfhydryl group pK(a) from 9.4 in aqueous solvent to 7.5 in the hydrocarbon ruler microenvironment. The Cys thiol is sandwiched at the interface between a nonpolar and a polar beta-barrel interior milieu, suggesting that local electrostatics near the otherwise hydrophobic hydrocarbon ruler pocket serve to perturb the thiol pK(a). Neutralization of the Cys thiolate anion by protonation restores wild-type exciton and thermal stability signatures to Gly88Cys PagP, which then functions as a dedicated myristoyltransferase at pH 7. Gly88Cys PagP assembled in bacterial membranes recapitulates lipid A myristoylation in vivo. Hydrocarbon ruler-exciton coupling in PagP thus reveals a thiol-thiolate ionization mechanism for modulating lipid acyl chain selection.

Inscribing the perimeter of the PagP hydrocarbon ruler by site-specific chemical alkylation.

The Escherichia coli outer membrane phospholipid:lipid A palmitoyltransferase PagP selects palmitate chains using its ß-barrel-interior hydrocarbon ruler and interrogates phospholipid donors by gating them laterally through an aperture known as the crenel. Lipid A palmitoylation provides antimicrobial peptide resistance and modulates inflammation signaled through the host TLR4/MD2 pathway. Gly88 substitutions can raise the PagP hydrocarbon ruler floor to correspondingly shorten the selected acyl chain. To explore the limits of hydrocarbon ruler acyl chain selectivity, we have modified the single Gly88Cys sulfhydryl group with linear alkyl units and identified C10 as the shortest acyl chain to be efficiently utilized. Gly88Cys-S-ethyl, S-n-propyl, and S-n-butyl PagP were all highly specific for C12, C11, and C10 acyl chains, respectively, and longer aliphatic or aminoalkyl substitutions could not extend acyl chain selectivity any further. The donor chain length limit of C10 coincides with the phosphatidylcholine transition from displaying bilayer to micellar properties in water, but the detergent inhibitor lauryldimethylamine N-oxide also gradually became ineffective in a micellar assay as the selected acyl chains were shortened to C10. The Gly88Cys-S-ethyl and norleucine substitutions exhibited superior C12 acyl chain specificity compared to that of Gly88Met PagP, thus revealing detection by the hydrocarbon ruler of the Met side chain tolerance for terminal methyl group gauche conformers. Although norleucine substitution was benign, selenomethionine substitution at Met72 was highly destabilizing to PagP. Within the hydrophobic and van der Waals-contacted environment of the PagP hydrocarbon ruler, side chain flexibility, combined with localized thioether-aromatic dispersion attraction, likely influences the specificity of acyl chain selection.

Biomechanical analysis of transverse acetabular fracture fixation in the elderly via the posterior versus the anterior approach with and without a total hip arthroplasty.

This study provides the first biomechanical comparison of the fixation constructs that can be created to treat transverse acetabular fractures when using the "gold-standard" posterior versus the anterior approach with and without a total hip arthroplasty in the elderly. Synthetic hemipelvises partially simulating osteoporosis (n = 24) were osteotomized to create a transverse acetabular fracture and then repaired using plates/screws, lag screws, and total hip arthroplasty acetabular components in one of four ways: posterior approach (n = 6), posterior approach plus a total hip arthroplasty acetabular component (n = 6), anterior approach (n = 6), and anterior approach plus a total hip arthroplasty acetabular component (n = 6). All specimens were biomechanically tested. No differences existed between groups for stiffness (range, 324.6-387.3 N/mm, p = 0.629), clinical failure load at 5 mm of femoral head displacement (range, 1630.1-2203.9 N, p = 0.072), or interfragmentary gapping (range, 0.67-1.33 mm, p = 0.359). Adding a total hip arthroplasty acetabular component increased ultimate mechanical failure load for posterior (2904.4 vs. 3652.3 N, p = 0.005) and anterior (3204.9 vs. 4396.0 N, p = 0.000) approaches. Adding a total hip arthroplasty acetabular component also substantially reduced interfragmentary sliding for posterior (3.08 vs. 0.50 mm, p = 0.002) and anterior (2.17 vs. 0.29 mm, p = 0.024) approaches. Consequently, the anterior approach with a total hip arthroplasty may provide the best biomechanical stability for elderly patients, since this fixation group had the highest mechanical failure load and least interfragmentary sliding, while providing equivalent stiffness, clinical failure load, and gapping compared to other surgical options.

Biomechanical Testing of a 3-Hole Versus a 4-Hole Sliding Hip Screw in the Presence of a Retrograde Intramedullary Nail for Ipsilateral Intertrochanteric and Femur Shaft Fractures.

OBJECTIVE: The goal of this study was to compare a 3-hole versus a 4-hole sliding hip screw (SHS) in the presence of a retrograde intramedullary (RIM) nail for fixing intertrochanteric and comminuted midshaft femur fractures. METHODS: Mechanical tests were performed on 10 matched pairs of human cadaveric femurs that were osteotomized and then fixed using a 3-hole SHS versus the traditional "gold standard" 4-hole SHS in the presence of an RIM nail. RESULTS: Data showed no differences between the 3-hole SHS with RIM nail versus 4-hole SHS with RIM nail for stiffness (281 ± 127 vs. 260 ± 118 N/mm, P = 0.76), clinical failure at 10 mm of hip displacement (2014 ± 363 vs. 2134 ± 614 N, P = 0.52), or ultimate mechanical failure (3476 ± 776 vs. 3669 ± 755 N, P = 0.12). CONCLUSIONS: For this fracture pattern, a 3-hole SHS with RIM nail may be a suitable surgical alternative to the traditional "gold standard" method because it provides the same biomechanical properties while potentially reducing surgical time, blood loss, and hardware used.

Development and Assessment of a Distal Radial Fracture Model as a Clinical Teaching Tool.

BACKGROUND: Simulation-based learning is increasingly prevalent in the curricula of many surgical training programs. Newly developed simulators must undergo rigorous validity testing before they are used to assess and evaluate surgical trainees. We describe the development of a model that simulates a distal radial fracture requiring closed reduction and cast application and demonstrate its validity. METHODS: We developed a model for simulated treatment of a distal radial fracture with use of a modified Sawbones forearm. Ten junior and ten senior orthopaedic residents were videotaped performing a closed reduction and applying a cast on the model. After each procedure, standard anteroposterior and lateral radiographs of the forearm model were obtained. Two blinded orthopaedic surgeons then rated each resident using a task-specific checklist (Objective Structured Assessment of Technical Skills [OSATS]) and a global rating scale (GRS) as well as radiographic measurements of palmar tilt and three-point index. RESULTS: Compared with the junior residents, senior residents had significantly higher OSATS (p < 0.001) and GRS scores (p < 0.001). The groups did not differ significantly with respect to radiographic palmar tilt (p = 0.86) and three-point index (p = 0.43). All residents were able to restore anatomical alignment, with a mean palmar tilt of 9.1°. In addition, the mean three-point index of all residents was acceptable (0.76). There was a strong correlation between OSATS and GRS scores (r > 0.87; p < 0.01). The inter-rater reliability was high (≥ 0.79) for the OSATS, GRS, and radiographic measurements. CONCLUSIONS: We developed an educational model that simulates a distal radial fracture requiring closed reduction and cast application. We demonstrated construct validity, as the GRS and OSATS tools were able to differentiate senior from junior residents. We were unable to differentiate trainees using radiographic assessment, as all residents restored anatomical alignment and had comparable three-point index scores.

Skill Acquisition and Retention Following Simulation-Based Training in Pavlik Harness Application.

BACKGROUND: Simulation-based learning is increasingly prevalent in many surgical training programs, as medical education moves toward competency-based curricula. In orthopaedic surgery, developmental dysplasia of the hip is a commonly treated condition, where the standard of care for patients less than six months of age is an orthotic device such as the Pavlik harness. However, despite widespread use of the Pavlik harness and the potential complications that may arise from inappropriate application, we know of no previously described formal training curriculum for Pavlik harness application. METHODS: We developed a video and model-based simulation learning module for Pavlik harness application. Two novice groups (residents and allied health professionals) were exposed to the module and, at pre-intervention, post-intervention, and retention testing, were evaluated on their ability to apply a Pavlik harness to the model. Evaluations were completed using a previously validated Objective Structured Assessment of Technical Skills (OSATS) and a global rating scale (GRS) specific to Pavlik harness application. A control group that did not undergo the module was also evaluated at two time points to determine if exposure to the Pavlik harness alone would affect skill acquisition. All groups were compared with a group of clinical experts, whose scores were used as a competency benchmark. Statistical analysis of skill acquisition and retention was conducted using t tests and analysis of variance (ANOVA). RESULTS: Exposure to the learning module improved resident and allied health professionals' competency in applying a Pavlik harness (p < 0.05) to the level of the expert clinicians, and this level of competency was retained one month after exposure to the module. Control subjects who were not exposed to the module did not improve, nor did they achieve competency. CONCLUSIONS: The simulation-based learning module was shown to be an effective tool for teaching the application of a Pavlik harness, and learners demonstrated retainable skills post-intervention. This learning module can form the cornerstone of formal teaching of Pavlik harness application for developmental dysplasia of the hip.

Education of parents in Pavlik harness application for developmental dysplasia of the hip using a validated simulated learning module.

BACKGROUND: The Pavlik harness is the most common initial treatment for developmental dysplasia of the hip worldwide. During treatment, parents are required to re-apply the harness at home. Teaching parents how to apply the harness is therefore paramount to success. While simulated learning for medical training is commonplace, it has not yet been trialed in teaching parents how to apply a Pavlik harness. METHODS: A group of parents underwent a simulated learning module for Pavlik harness application. Parents were evaluated pre- and post-exposure and at one month after testing. A validated objective structured assessment of technical skill (OSATS) and a global rating scale (GRS) specific to Pavlik harness application were used for evaluation. A control group of parents was also tested at both time points. A clinical expert group was used to determine competency. ANOVA and t tests were used to assess differences between groups and over time. RESULTS: Parent scores on the OSATS improved to the level of expert clinicians both immediately post-intervention and at retention testing. However, on the GRS, only half were considered competent due to their inability to achieve the required hip positions. The control group did not improve nor were they considered competent. CONCLUSIONS: The use of a simulated learning module improves both the confidence and skill level of parents in the application of the Pavlik harness. However, the challenges parents face in understanding the more detailed subtleties of medical care suggest that they still require an appropriate level of supervision by clinicians to ensure effective treatment.

Development of a cast application simulator and evaluation of objective measures of performance.

BACKGROUND: Surgical simulation offers a low-risk learning environment with repetitive practice opportunities for orthopaedic residents. It is increasingly prevalent in many training programs, as acquisition of technical skills in the face of educational demands and reduced work hours becomes more challenging. In addition to surgical skills, orthopaedic residents must also learn the technique of cast application. Deficiencies in casting skill are risk factors for re-displacement of fractures and cast-specific complications. Formal educational models to instruct or to evaluate casting technique have not been well described or tested. The purposes of this study were to develop a cast application simulator and to validate a novel method of evaluating casting skill. METHODS: A module that simulates short arm cast application on a synthetic forearm model was developed. An Objective Structured Assessment of Technical Skill checklist was created with use of Delphi methodology involving nine content experts (five orthopaedic surgeons and four orthopaedic technologists). Nine participants (three medical students, three orthopaedic residents, two orthopaedic fellows, and one orthopaedic technologist) were used to evaluate the reliability and validity of the checklist. Nine de-identified videos of cast application were recorded and were utilized to test the newly developed Objective Structured Assessment of Technical Skill checklist and Modified Global Rating Scale for reliability and validity. Participants were grouped by training level (medical students, orthopaedic residents, and orthopaedic fellows or orthopaedic technologists) and were evaluated twice. RESULTS: Reliability was high as shown by intraclass correlation. The inter-rater reliability was 0.85 for the Objective Structured Assessment of Technical Skill, 0.81 for the Modified Global Rating Scale performance, and 0.78 for the Modified Global Rating Scale final product; the intra-rater reliability was 0.88 for the Objective Structured Assessment of Technical Skill, 0.85 for the Modified Global Rating Scale performance, and 0.81 for the Modified Global Rating Scale final product. The Objective Structured Assessment of Technical Skill checklist scores were 9.28 points for the medical students, 17.46 points for the orthopaedic residents, and 18.85 points for the orthopaedic fellows or orthopaedic technologists (p < 0.05, F = 6.32). The Modified Global Rating Scale performance and final product scores also reflected the level of training. Post hoc analysis showed a significant difference between the medical students and orthopaedic fellows or orthopaedic technologists for the Objective Structured Assessment of Technical Skill checklist and Modified Global Rating Scale. CONCLUSIONS: This casting simulation model and evaluation instrument is a reliable assessment of casting skill in applying a short arm cast. However, given the inability to stratify all three groups on the basis of the level of training, further work is needed to establish construct validity.

PagP crystallized from SDS/cosolvent reveals the route for phospholipid access to the hydrocarbon ruler.

Enzymatic reactions involving bilayer lipids occur in an environment with strict physical and topological constraints. The integral membrane enzyme PagP transfers a palmitoyl group from a phospholipid to lipid A in order to assist Escherichia coli in evading host immune defenses during infection. PagP measures the palmitoyl group with an internal hydrocarbon ruler that is formed in the interior of the eight-stranded antiparallel ß barrel. The access and egress of the palmitoyl group is thought to take a lateral route from the bilayer phase to the barrel interior. Molecular dynamics, mutagenesis, and a 1.4 A crystal structure of PagP in an SDS / 2-methyl-2,4-pentanediol (MPD) cosolvent system reveal that phospholipid access occurs at the crenel present between strands F and G of PagP. In this way, the phospholipid head group can remain exposed to the cell exterior while the lipid acyl chain remains in a predominantly hydrophobic environment as it translocates to the protein interior.