Disease diagnosis and arthroplasty type are strongly associated with short-term postoperative patient-reported outcomes in patients undergoing primary total shoulder arthroplasty.

BACKGROUND: Prognostic factors for total shoulder arthroplasty (TSA) clinical outcomes are incompletely understood. This study investigates the associations of preoperative patient, disease-specific, and surgical factors with 1-year postoperative PENN Shoulder Score (PSS) in patients undergoing primary TSA. METHODS: Cleveland Clinic patients undergoing primary anatomic TSA (aTSA) or reverse TSA (rTSA) for glenohumeral osteoarthritis (GHOA) or rotator cuff tear arthropathy (CTA) between February 2015 and August 2019, and having complete preoperative and 1-year postoperative patient-reported outcome measures (PROMs), were included. Twenty preselected preoperative patient, disease-specific, and surgical factors were used to fit multivariable models for 1-year PSS and its subscores. RESULTS: Of 1427 eligible primary TSAs, 1174 had 1-year follow-up by PROMs (82%), with 1042 analyzed after additional exclusions, including 30% rTSAs for CTA (n = 308), 26% rTSAs for GHOA (n = 275), and 44% aTSAs for GHOA (n = 459). All PROMs showed statistically significant improvements postoperatively, with 89% of patients reaching an acceptable symptom state. Lower 1-year PSS was associated with younger age, female sex, current smoking, chronic pain diagnosis, history of prior surgery, worker's compensation claim, lower preoperative mental health, lower baseline PSS, absence of glenoid bone loss, and diagnosis-arthroplasty type (CTA-rTSA < GHOA-rTSA < GHOA-aTSA). The most important prognostic factors associated with 1-year PSS were diagnosis-arthroplasty type, baseline mental health status, and insurance status. CONCLUSIONS: Disease diagnosis, arthroplasty type, and several other baseline factors are strongly and individually associated with PROMs following primary TSA, with patients undergoing aTSA for GHOA demonstrating the highest PROM scores at 1-year follow-up. Patient, disease-specific, and surgical factors can be used to guide postoperative prognosis following primary TSA for improved preoperative patient counseling regarding expected outcomes of these procedures.

Three-dimensional computed tomography analysis of pathologic correction in total shoulder arthroplasty based on severity of preoperative pathology.

BACKGROUND: The purpose of this study was to quantify correction of glenoid deformity and humeral head alignment in anatomic total shoulder arthroplasty as a function of preoperative pathology (modified Walch classification) and glenoid implant type in a clinical cohort using 3-dimensional computed tomography (CT) analysis. METHODS: Patients undergoing anatomic total shoulder arthroplasty with a standard glenoid (SG) (n = 110) or posteriorly stepped augmented glenoid (AG) (n = 62) component were evaluated with a preoperative CT scan and a postoperative CT scan within 3 months of surgery. Glenoid version, inclination, and medial-lateral (ML) joint line position, as well as humeral head alignment, were assessed on both CT scans, with preoperative-to-postoperative changes analyzed relative to pathology and premorbid anatomy based on the modified Walch classification and glenoid implant type. RESULTS: On average, correction to the premorbid ML joint line position was significantly less in type A2 glenoids than in type A1 glenoids (-2.3 ± 2.1 mm vs. 1.1 ± 0.9 mm, P < .001). Correction to premorbid version was not different between type B2 glenoids with AG components and type A1 glenoids with SG components (-1.7° ± 6.6° vs. -1.0° ± 4.0°, P = .57), and the premorbid ML joint line position was restored on average in both groups (0.3 ± 1.6 mm vs. 1.1 ± 0.9 mm, P = .006). Correction to premorbid version was not different between type B3 glenoids with AG components and type A1 glenoids with SG components (-0.6° ± 5.1° vs. -1.0° ± 4.0°, P = .72), but correction relative to the premorbid ML joint line position was significantly less in type B3 glenoids with AG components than in type A1 glenoids with SG components (-2.2 ± 2.1 mm vs. 1.1 ± 0.9 mm, P < .001). Postoperative humeral glenoid alignment was not different in any group comparisons. DISCUSSION: In cases with posterior glenoid bone loss and retroversion (type B2 or B3 glenoids), an AG component can better correct retroversion and the glenoid ML joint line position compared with an SG component, with correction to premorbid version comparable to a type A1 glenoid with an SG component. However, restoration of the premorbid ML joint line position may not always be possible with SG or AG components in cases with more advanced central glenoid bone loss (type A2 or B3 glenoids). Further follow-up is needed to determine the clinical consequences of these findings.

Associations of preoperative patient mental health status and sociodemographic and clinical characteristics with baseline pain, function, and satisfaction in patients undergoing primary shoulder arthroplasty.

HYPOTHESIS AND BACKGROUND: Shoulder pain and dysfunction are common indications for shoulder arthroplasty, yet the factors that are associated with these symptoms are not fully understood. This study aimed to investigate the associations of patient and disease-specific factors with preoperative patient-reported outcome measures (PROMs) in patients undergoing primary shoulder arthroplasty. We hypothesized that worse mental health status assessed by the Veterans RAND 12-Item Health Survey (VR-12) mental component score (MCS), glenoid bone loss, and increasing rotator cuff tear severity would be associated with lower values for the preoperative total Penn Shoulder Score (PSS) and its pain, function, and satisfaction subscores. METHODS: We prospectively identified 12 patient factors and 4 disease-specific factors as possible statistical predictors of preoperative PROMs in patients undergoing primary shoulder arthroplasty at a single institution over a 3-year period. Multivariable statistical modeling and Akaike information criterion comparisons were used to investigate the unique associations with, and relative importance of, these factors in accounting for variation in the preoperative PSS and its subscores. RESULTS: A total of 788 cases performed by 12 surgeons met the inclusion criteria, with a preoperative median total PSS of 31 points (pain, 10 points; function, 18 points; and satisfaction, 1 point). As hypothesized, a lower VR-12 MCS was associated with lower preoperative PSS pain, function, and total scores, but patients with intact status or small to medium rotator cuff tears had modestly lower PSS pain subscores (ie, more pain) than patients with large to massive superior-posterior rotator cuff tears. Glenoid bone loss was not associated with the preoperative PSS. Female sex and fewer years of education (for all 4 outcomes), lower VR-12 MCS and preoperative opioid use (for all outcomes but satisfaction), and rotator cuff tear severity (for pain only) were the factors most prominently associated with preoperative PROMs. CONCLUSION: In addition to mental health status and rotator cuff tear status, patient sex, years of education, and preoperative opioid use were most prominently associated with preoperative PROMs in patients undergoing shoulder arthroplasty. Further studies are needed to investigate whether these factors will also predict postoperative PROMs.

Inter-rater agreement of rotator cuff tendon and muscle magnetic resonance imaging parameters evaluated preoperatively and during the first postoperative year following rotator cuff repair.

BACKGROUND: Magnetic resonance imaging (MRI) is standard of care for rotator cuff evaluation, with clinical interpretation usually limited to qualitative judgments. The reliability of MRI-based measurements and scoring systems has been evaluated only preoperatively or ≥6 months following rotator cuff repair, when repairs are in the later stages of healing. This study describes the MRI assessments and inter-rater agreement of various rotator cuff tendon and muscle parameters evaluated preoperatively and 4 times during the first postoperative year. METHODS: Two musculoskeletal radiologists independently assessed MRI scans of 42 patients preoperatively and 3, 12, 26, and 52 weeks after rotator cuff repair. Using standardized reading rules, readers assessed tendon integrity (5-point Sugaya classification), tear dimensions, muscle fat (5-point Goutallier classification) and atrophy (4-point Warner classification), muscle cross-sectional areas, and myotendinous junction distance. Raw exact agreement proportions, κ statistics, and correlation coefficients were used to quantify inter-rater agreement. RESULTS: Readers showed moderate to substantial above-chance agreement in scoring rotator cuff tendon integrity and supraspinatus muscle atrophy and good to excellent agreement on tear dimensions and muscle cross-sectional areas but only fair to moderate agreement for fatty infiltration and myotendinous junction distance. Only fatty infiltration grades evidenced observer bias. Inter-rater agreement did not appear time dependent. CONCLUSION: By use of defined reading rules in a research setting, MRI evaluations of rotator cuff tendon integrity, tear dimensions, muscle atrophy, and cross-sectional areas have reasonable reliability at all time points in the first postoperative year. However, the presence of clinically significant disagreements, even in such favorable circumstances, indicates the need for improved imaging tools for precise rotator cuff evaluation.

Effectiveness of a Web-Based Electronic Prospective Data Collection Tool for Surgical Data in Shoulder Arthroplasty.

BACKGROUND: The purpose of this study was to demonstrate the validity and efficiency of the Outcomes Management and Evaluation (OME) system, a prospectively designed electronic data collection tool, for collecting comprehensive and standardized surgical data in shoulder arthroplasty. METHODS: Surgical data from the first 100 cases of shoulder arthroplasty that were collected into the OME database were analyzed. Surgeons completed a traditional narrative operative note and also an OME case report using an encrypted smartphone. A blinded reviewer extracted data from the operative notes and implant logs in the electronic medical records (EMR) by manual chart review. OME and EMR data were compared with regard to data counts and agreement between 39 variables related to preoperative pathology, including rotator cuff status and glenoid wear, and surgical procedures. Data counts were assessed using both raw percentages and with McNemar's test (with continuity correction). Agreement of nominal variables was analyzed using Cohen's unweighted kappa (κ) and of ordinal variables using the linearly weighted Cohen's test. Efficiency was assessed by calculating the median time needed to complete OME. RESULTS: Compared to the EMR, the OME database had significantly higher data counts for 56% (22 of 39) of the variables assessed. A high level of proportional and statistical agreement was demonstrated between the data in the two datasets. 10 of 39 variables had 100% agreement but could not be statistically compared because both datasets had the same single response under those variables. Among the 29 variables that were compared, 79% (23 of 29) of variables had >80% raw proportional agreement, and 69% (20 of 29) of variables showed at least substantial agreement (κ > 0.6). The median time for completing OME surgery data entry was 92 seconds (IQR 70 - 126). CONCLUSION: The prospectively designed, electronic data entry system (OME) is an efficient and valid tool for collecting comprehensive and standardized surgical data on shoulder arthroplasty. LEVEL OF EVIDENCE: Level IV.

Tear characteristics and surgeon influence repair technique and suture anchor use in repair of superior-posterior rotator cuff tendon tears.

BACKGROUND: The factors that associate with surgical decisions about repair technique and the number of suture anchors used in rotator cuff repair have not been previously investigated. This study investigated the extent to which patient, surgeon, and surgical factors associate with performing single-row vs. double-row repair technique and ultimately with the number of suture anchors used. METHODS: Our institution's prospective surgical cohort was queried for patients undergoing suture anchor repair of superior-posterior rotator cuff tendon tears between February 2015 and August 2017. Exclusion criteria were patients with isolated subscapularis tears, tears that were not repaired, repairs without suture anchors, repairs involving graft augmentation, and repairs by surgeons with fewer than 10 cases. Multivariable statistical modeling was used to investigate associations between patient and surgical factors and the choice of repair technique and number of suture anchors used. RESULTS: A total of 925 cases performed by 13 surgeons met inclusion criteria. Tear type (full thickness), tear size (medium, large, and massive), a greater number of torn tendons, repair type (arthroscopic), and surgeon were significantly associated with performing a double-row over a single-row repair. Tear size, a greater number of torn tendons, double-row repair technique, and surgeon were significantly associated with a greater number of anchors used for repair. CONCLUSIONS: Our findings suggest that in the absence of data to conclusively support a clinical benefit of one repair technique over another, surgeons' training, experience, and inherent practice patterns become the primary factors that define their surgical methods.

Validity and efficiency of a smartphone-based electronic data collection tool for operative data in rotator cuff repair.

BACKGROUND: This study tested validity and efficiency of Orthopaedic Minimal Data Set (OrthoMiDaS) Episode of Care (OME). METHODS: We analyzed 100 isolated rotator cuff repair cases in the OME database. Surgeons completed a traditional operative note and OME report. A blinded reviewer extracted data from operative notes and implant logs in electronic medical records by manual chart review. OME and electronic medical record data were compared with data counts and agreement between 40 variables of rotator cuff disease and repair procedures. Data counts were assessed using raw percentages and McNemar test (with continuity correction). Agreement of categorical variables was analyzed using Cohen κ (unweighted) and of numerical variables using the concordance correlation coefficient (CCC). Efficiency was assessed by median time to complete. RESULTS: OME database had significantly higher data counts for 25% (10/40) of variables. A high level of proportional and statistical agreement was demonstrated between the data. Among 35 categorical variables, proportional agreement was perfect for 17%, almost perfect (0.81 ≤ κ ≤ 1.00) for 37%, substantial (0.61 ≤ κ ≤ 0.80) for 20%, moderate (0.41 ≤ κ ≤ 0.60) for 14%, fair (0.21 ≤ κ ≤ 0.40) for 6%, and slight (0.0 ≤ κ ≤ 0.20) for 6%. Of 5 numerical variables, agreement was almost perfect (CCC > 0.99) for 20% and poor (CCC < 0.90) for 80%. Median OME completion time was 161.5 seconds (interquartile range, 116-224.5). CONCLUSION: OME is an efficient, valid tool for collecting comprehensive, standardized data on rotator cuff repair.

Hemolytic strains of Propionibacterium acnes do not demonstrate greater pathogenicity in periprosthetic shoulder infections.

BACKGROUND: Hemolysis has been suggested as a feature conferring increased pathogenicity to certain Propionibacterium acnes strains in the setting of shoulder infection. The purpose of this study was to compare the virulence of hemolytic and nonhemolytic P acnes strains in patients undergoing revision shoulder arthroplasty. METHODS: Thirty-nine patients with at least 1 positive culture growth for P acnes at the time of revision surgery were identified with P acnes isolates available for hemolysis testing. Patients were grouped into those with P acnes isolates positive (n = 20) and negative (n = 19) for hemolysis. The groups were retrospectively compared based on objective perioperative findings around the time of revision surgery and the postoperative clinical course, including the need for revision surgery. All cases were classified into categories of infection (definite infection, probable infection, and probable contaminant) based on objective perioperative criteria. RESULTS: The presence of hemolysis was not significantly associated with an increased likelihood of infection (P = .968). Hemolysis demonstrated a 75% sensitivity and 26% specificity for determining infection (definite infection and probable infection categories). The hemolytic and nonhemolytic groups showed no difference regarding preoperative serum erythrocyte sedimentation rate and/or C-reactive protein level (P = .70), number of positive cultures (P = .395), time to positive culture (P = .302), and presence of positive frozen section findings (P = .501). Postoperatively, clindamycin resistance, shoulder function, and the rate of reoperation were not significantly different between the hemolytic and nonhemolytic groups. CONCLUSION: The presence of hemolysis was not associated with increased pathogenicity in patients with P acnes-positive cultures following revision shoulder arthroplasty, when assessed by objective perioperative criteria and the postoperative clinical course.

Augmentation with a reinforced acellular fascia lata strip graft limits cyclic gapping of supraspinatus repairs in a human cadaveric model.

BACKGROUND: A reinforced biologic strip graft was designed to mechanically augment the repair of rotator cuff tears that are fully reparable by arthroscopic techniques yet have a likelihood of failure. This study assessed the extent to which augmentation of human supraspinatus repairs with a reinforced fascia strip can reduce gap formation during in vitro cyclic loading. METHODS: The supraspinatus tendon was sharply released from the proximal humerus and repaired back to its insertion with anchors in 9 matched pairs of human cadaveric shoulders. One repair from each pair was also augmented with a reinforced fascia strip. All repairs were subjected to cyclic mechanical loading of 5 to 180 N for 1000 cycles. RESULTS: All augmented and nonaugmented repair constructs completed 1000 cycles of loading. Augmentation with a reinforced fascia strip graft significantly decreased the amount of gap formation compared with nonaugmented repairs. The average gap formation of augmented repairs was 1.5 ± 0.7 mm after the first cycle vs. 3.0 ± 1.2 mm for nonaugmented repairs (P = .003) and 5.0 ± 1.5 mm after 1000 cycles of loading, which averaged 24% ± 21% less than the gap formation of nonaugmented repairs (7.0 ± 2.8 mm, P = .014). CONCLUSION: Cadaveric human supraspinatus repairs augmented with a reinforced fascia strip have significantly less initial stroke elongation and gap formation than repairs without augmentation. Augmentation limited gap formation to the greatest extent early in the testing protocol. Human studies are necessary to confirm the appropriate indications and effectiveness of augmentation scaffolds for rotator cuff repair healing in the clinical setting.

Development of a critical-sized ventral hernia model in the pig.

BACKGROUND: The pig is commonly used as a preclinical model for ventral hernia repair. However, no study has verified that an unrepaired surgically induced hernia (control) in the pig does not heal spontaneously but rather develops a persistent hernia. Without such verification in any given model, one cannot draw conclusions on the efficacy of the repair technique investigated. MATERIALS AND METHODS: Three surgically induced hernia models with increasing severity were created in eight pigs. These included 10-cm retrorectus partial-thickness (model 1) and 15-cm preperitoneal full-thickness (model 2) incisional defects and an 8 × 8 cm preperitoneal full-thickness excisional defect (model 3). Postoperative management included use of an abdominal binder, and in some cases, suction drainage, for 2 wk to support the repair and prevent seroma. Models were evaluated for persistence of hernia at 5 wk using clinical and radiographic assessments. RESULTS: All pigs developed clinical hernias after 2 wk of defect creation, but only models 1 and 3 had clinically persistent hernias at 5 wk. At 5 wk, the average defect area was 97 cm2 in model 1, 66 cm2 in model 2, and 245 cm2 in model 3. Dense fibrotic scarring was observed in the models with resolved hernias. CONCLUSIONS: Our results highlight the need to verify an unrepaired hernia injury model does not heal spontaneously prior to using it for hernia repair studies. The partial-thickness incisional model 1 and full-thickness excisional model 3 formed persistent hernias in pigs at 5 wk and should be further explored as models for investigating hernia repair strategies.

Neer Award 2015: Analysis of cytokine profiles in the diagnosis of periprosthetic joint infections of the shoulder.

BACKGROUND: Periprosthetic joint infection (PJI) after shoulder arthroplasty can present a diagnostic and therapeutic challenge. This study evaluated the diagnostic utility of broader synovial fluid cytokine analysis for identifying PJI in patients undergoing revision shoulder arthroplasty. METHODS: Synovial fluid levels of 9 cytokines (interleukin [IL] 6, granulocyte-macrophage colony-stimulating factor, IL-1ß, IL-12, IL-2, IL-8, interferon-γ, IL-10, and tumor necrosis factor-α) were measured in 75 cases of revision shoulder arthroplasty with a multiplex immunoassay. Cases were classified into infection categories and groups based on objective perioperative findings. Differences in cytokine levels among infection groups were evaluated. Receiver operating characteristic curves were used to assess the diagnostic utility of the individual synovial fluid cytokines and combinations of cytokines in determining infection status. RESULTS: Synovial IL-6, granulocyte-macrophage colony-stimulating factor, interferon-γ, IL-1ß, IL-2, IL-8, and IL-10 were significantly elevated in cases of revision shoulder arthroplasty classified as infected. Individually, IL-6, IL-1ß, IL-8, and IL-10 showed the best combination of sensitivity and specificity for predicting infection, and a combined cytokine model consisting of IL-6, tumor necrosis factor-α, and IL-2 showed better diagnostic test characteristics than any cytokine alone, with sensitivity of 0.80, specificity of 0.93,, positive and negative predictive values of 0.87 and 0.89, and positive and negative likelihood ratios of 12.0 and 0.21. CONCLUSIONS: Individual and combined synovial fluid cytokine analysis were both more effective than routine perioperative testing, such as serum erythrocyte sedimentation rate and C-reactive protein, in the diagnosis of PJI of the shoulder. Once validated, combined synovial fluid cytokine analysis could be used as a predictive tool to determine the probability of PJI in patients undergoing revision shoulder arthroplasty and better guide treatment.

One-year patient-reported outcomes following primary arthroscopic rotator cuff repair vary little by surgeon.

Background: This study's purpose was to investigate the extent to which differences among operating surgeons may influence 1-year patient-reported outcome measures (PROMs) in patients undergoing rotator cuff repair (RCR) surgery, after controlling for general and disease-specific patient factors. We hypothesized that surgeon would be additionally associated with 1-year PROMs, specifically the baseline to 1-year improvement in Penn Shoulder Score (PSS). Methods: We used mixed multivariable statistical modeling to assess the influence of surgeon (and alternatively surgical case volume) on 1-year PSS improvement in patients undergoing RCR at a single health system in 2018, controlling for eight patient- and six disease-specific preoperative factors as possible confounders. Contributions of predictors to explaining variation in 1-year PSS improvement were measured and compared using Akaike's Information Criterion. Results: 518 cases performed by 28 surgeons met inclusion criteria, with median (quartiles) baseline PSS of 41.9 (31.9, 53.9) and 1-year PSS improvement of 42 (29.1, 55.3) points. Contrary to expectation, surgeon and surgical case volume were neither statistically significantly nor clinically meaningfully associated with 1-year PSS improvement. Baseline PSS and mental health status (VR-12 MCS) were the dominant and only statistically significant predictors of 1-year PSS improvement, with lower baseline PSS and higher VR-12 MCS predicting larger 1-year PSS improvement. Conclusion: Patients generally reported excellent 1-year outcomes following primary RCR. This study did not find evidence that the individual surgeon or surgeon case volume influences 1-year PROMs, independently of case-mix factors, following primary RCR in a large employed hospital system.

Does augmentation with a reinforced fascia patch improve rotator cuff repair outcomes?

BACKGROUND: Scaffold devices are used to augment rotator cuff repairs in humans. While the strength of a novel poly-L-lactic acid-reinforced (human) fascia patch has been documented, it is unclear whether such patches will enhance the strength or likelihood of healing of rotator cuff repairs. QUESTIONS/PURPOSES: In a canine shoulder model, we asked: Do tendon repairs augmented with a reinforced fascia patch have (1) increased biomechanical properties at Time 0 and (2) less tendon retraction and increased cross-sectional area and biomechanical properties after 12 weeks of healing compared to repairs without augmentation? (3) Do the biomechanical properties of tendon repairs reach normal values by 12 weeks of healing? And (4) is the host response associated with use of the reinforced fascia patch biocompatible? METHODS: Eleven dogs underwent bilateral shoulder surgery with partial release and acute repair of the infraspinatus tendon, one shoulder with augmentation and one without augmentation. Repair retraction, cross-sectional area, biomechanical properties, and biocompatibility were assessed at 12 weeks. RESULTS: At Time 0, the mean ± SD ultimate load of augmented repairs was 296 ± 130 N (46% ± 25%) more than nonaugmented repairs, with no difference in stiffness between groups. At 12 weeks, the ultimate load of augmented repairs averaged 192 ± 213 N (15% ± 16%) less than nonaugmented repairs, with no difference in stiffness between groups. At the tendon repair site at 12 weeks, the fascia patch showed a biocompatible host tissue response. CONCLUSIONS: The biomechanical properties of repairs augmented with a reinforced fascia patch demonstrated greater ultimate load at Time 0 than nonaugmented repairs but remained essentially unchanged after 12 weeks of healing, despite improvements in the ultimate load of nonaugmented controls in the same time frame.

Measurement of in vivo tendon function.

Chronic tendon pathologies (eg, rotator cuff tears, Achilles tendon ruptures) are common, painful, debilitating, and a significant source of medical expense. Treatment strategies for managing tendon pathologies vary widely in invasiveness and cost, with little scientific basis on which to base treatment selection. Conventional techniques for assessing the outcomes of physical therapy or surgical repair typically rely on patient-based assessments of pain and function, physical measures (eg, strength, range of motion, or stability), and qualitative assessments using magnetic resonance imaging or ultrasound. Unfortunately, these conventional techniques provide only an indirect assessment of tendon function. The inability to make a direct quantitative assessment of the tendon's mechanical capabilities may help to explain the relatively high rate of failed tendon repairs and has led to an interest in the development of tools for directly assessing in vivo tendon function. The purpose of this article is to review methods for assessing tendon function (ie, mechanical properties and capabilities) during in vivo activities. This review will describe the general principles behind the experimental techniques and provide examples of previous applications of these techniques. In addition, this review will characterize the advantages and limitations of each technique, along with its potential clinical utility. Future efforts should focus on developing broadly translatable technologies for quantitatively assessing in vivo tendon function. The ability to accurately characterize the in vivo mechanical properties of tendons would improve patient care by allowing for the systematic development and assessment of new techniques for treating tendon pathologies.

Scaffold devices for rotator cuff repair.

Rotator cuff tears affect 40% or more of those aged older than 60 years, and repair failure rates of 20% to 70% remain a significant clinical challenge. Hence, there is a need for repair strategies that can augment the repair by mechanically reinforcing it, while at the same time biologically enhancing the intrinsic healing potential of the tendon. Tissue engineering strategies to improve rotator cuff repair healing include the use of scaffolds, growth factors, and cell seeding, or a combination of these approaches. Currently, scaffolds derived from mammalian extracellular matrix, synthetic polymers, and a combination thereof, have been cleared by the U.S. Food and Drug Administration and are marketed as medical devices for rotator cuff repair in humans. Despite the growing clinical use of scaffold devices for rotator cuff repair, there are numerous questions related to their indication, surgical application, safety, mechanism of action, and efficacy that remain to be clarified or addressed. This article reviews the current basic science and clinical understanding of commercially available synthetic and extracellular matrix scaffolds for rotator cuff repair. Our review will emphasize the host response and scaffold remodeling, mechanical and suture-retention properties, and preclinical and clinical studies on the use of these scaffolds for rotator cuff repair. We will discuss the implications of these data on the future directions for use of these scaffolds in tendon repair procedures.

Reinforced fascia patch limits cyclic gapping of rotator cuff repairs in a human cadaveric model.

BACKGROUND: Scaffolds continue to be developed and used for rotator cuff repair augmentation, but clinical or biomechanical data to inform their use are limited. We have developed a reinforced fascia lata patch with mechanical properties to meet the needs of musculoskeletal applications. The objective of this study was to assess the extent to which augmentation of a primary human rotator cuff repair with the reinforced fascia patch can reduce gap formation during in vitro cyclic loading. MATERIALS AND METHODS: Nine paired human cadaveric shoulders were used to investigate the cyclic gap formation and failure properties of augmented and non-augmented rotator cuff repairs with loading of 5 to 180 N for 1000 cycles. RESULTS: Augmentation significantly decreased the amount of gap formation at cycles 1, 10, 100, and 1000 compared with non-augmented repairs (P < .01). The mean gap formation of the augmented repairs was 1.8 mm after the first cycle of pull (vs 3.6 mm for non-augmented repairs) and remained less than 5 mm after 1000 cycles of loading (4.7 mm for augmented repairs vs 7.3 mm for non-augmented repairs). Furthermore, all augmented repairs were able to complete the 1000-cycle loading protocol, whereas 3 of 9 non-augmented repairs failed before completing 1000 loading cycles. CONCLUSIONS: This study supports further investigation of reinforced fascia patches to provide mechanical augmentation, minimize tendon retraction, and possibly reduce the incidence of rotator cuff repair failure. Future investigation in animal and human studies will be necessary to fully define the efficacy of the reinforced fascia device in a biologic healing environment.

The biomechanical role of scaffolds in augmented rotator cuff tendon repairs.

BACKGROUND: Scaffolds continue to be developed and used for rotator cuff repair augmentation; however, the appropriate scaffold material properties and/or surgical application techniques for achieving optimal biomechanical performance remains unknown. The objectives of the study were to simulate a previously validated spring-network model for clinically relevant scenarios to predict: (1) the manner in which changes to components of the repair influence the biomechanical performance of the repair and (2) the percent load carried by the scaffold augmentation component. MATERIALS AND METHODS: The models were parametrically varied to simulate clinically relevant scenarios, namely, changes in tendon quality, altered surgical technique(s), and different scaffold designs. The biomechanical performance of the repair constructs and the percent load carried by the scaffold component were evaluated for each of the simulated scenarios. RESULTS: The model predicts that the biomechanical performance of a rotator cuff repair can be modestly increased by augmenting the repair with a scaffold that has tendon-like properties. However, engineering a scaffold with supraphysiologic stiffness may not translate into yet stiffer or stronger repairs. Importantly, the mechanical properties of a repair construct appear to be most influenced by the properties of the tendon-to-bone repair. The model suggests that in the clinical setting of a weak tendon-to-bone repair, scaffold augmentation may significantly off-load the repair and largely mitigate the poor construct properties. CONCLUSIONS: The model suggests that future efforts in the field of rotator cuff repair augmentation may be directed toward strategies that strengthen the tendon-to-bone repair and/or toward engineering scaffolds with tendon-like mechanical properties.

Effect of pretension and suture needle type on mechanical properties of acellular human dermis patches for rotator cuff repair.

BACKGROUND: Dermal grafts are used for rotator cuff repair and augmentation. Although the in vitro biomechanical properties of dermal grafts have been reported previously, clinical questions related to their biomechanical performance as a surgical construct and the effect of surgical variables that could potentially improve repair outcomes have not been studied. METHODS: This study evaluated the failure and fatigue biomechanics of acellular dermis constructs tested in a clinically relevant size (4 × 4 cm patches) and manner (loaded via sutures) for rotator cuff repair. Also investigated were the effect of 2 surgical variables: (1) the fixation of grafts under varying magnitudes of pretension (0, 10, 20N), and (2) the use of reverse-cutting vs tapered needles for suturing grafts. RESULTS: Dermis constructs stretched ∼25% before bearing significant loads in the high stiffness region. Although 91% of the patches withstood 2500 cycles of loading to 150 N, the constructs stretched 13 to 19 mm after fatigue loading. This elongation could be reduced by 20% to 32% when reverse-cutting needles were used to prepare constructs or by applying 20 N of in situ circumferential pretension to the constructs before loading. CONCLUSIONS: Although dermis patches demonstrated robustness for use in rotator cuff repair, the patches underwent significant, substantial, and presumably nonrecoverable elongation, even at low physiologic loads. This study indicates that use of reverse-cutting needles for suture passage, preconditioning (cyclically stretching several times), and/or surgical fixation under at least 20 N of circumferential pretension could be developed as strategies to reduce compliance of dermis for its use for rotator cuff repair.

Changes From Baseline in Patient- Reported Outcomes at 1 Year Versus 2 Years After Rotator Cuff Repair: A Systematic Review and Meta-analysis.

BACKGROUND: Most orthopaedic journals currently require reporting outcomes of surgical interventions for at least 2 postoperative years, but there have been no rigorous studies on this matter. Various patient-reported outcome (PRO) measures (PROMs) have been used to assess the status of the shoulder after rotator cuff repair (RCR). HYPOTHESIS: We hypothesized that the mean shoulder-specific PROMs at 1 year improve substantially over baseline but that there is no clinically meaningful difference between the mean 1- and 2-year PROMs after RCR. STUDY DESIGN: Meta-analysis; Level of evidence, 2. METHODS: We conducted a systematic review of published randomized controlled trials (RCTs) and prospective cohort studies (level of evidence 1 and 2) reporting the shoulder-specific American Shoulder and Elbow Surgeons (ASES), the Constant, or the Western Ontario Rotator Cuff (WORC) Index scores at baseline, 1 year, and 2 years after RCR. The methodologic quality of studies was assessed. Also, the random effects meta-analyses of changes in PROMs for each of the first and second postoperative years were conducted. RESULTS: Fifteen studies (n = 11 RCTs; n = 4 cohort studies) with a total of 1371 patients were included. Studies were highly heterogeneous, but no visual evidence of major publication bias was observed. The weighted means of the baseline PROMs were 46.2 points for the ASES score, 46.4 points for the Constant score, and 38.8 points for the WORC Index. The first-year summary increments were 41.1 (95% CI, 36.0-46.2) points for the ASES score, 34.2 (95% CI, 28.8-39.6) points for the Constant score, and 42.9 (95% CI, 37.3-48.4) points for the WORC Index. In contrast, the second-year summary increments were 2.3 (95% CI, 1-3.6) points for the ASES score, 3.2 (95% CI, 1.9-4.4) points for the Constant score, and 2 (95% CI, -0.1 to 4) points for the WORC Index. CONCLUSION: All PROMs improved considerably from baseline to 1 year, but only very small gains that were below the minimal clinically important differences were observed between 1 year and 2 years after RCR. This study did not find any evidence for requiring a minimum of 2 years of follow-up for publication of PROs after RCR. Our results suggest that focusing on 1-year PROMs after RCR would foster more timely reporting, better control of selection bias, and better allocation of research resources.