Mechanistic modeling of empty-full separation in recombinant adeno-associated virus production using anion-exchange membrane chromatography.

Recombinant adeno-associated viral vectors (rAAVs) have become an industry-standard technology in the field of gene therapy, but there are still challenges to be addressed in their biomanufacturing. One of the biggest challenges is the removal of capsid species other than that which contains the gene of interest. In this work, we develop a mechanistic model for the removal of empty capsids-those that contain no genetic material-and enrichment of full rAAV using anion-exchange membrane chromatography. The mechanistic model was calibrated using linear gradient experiments, resulting in good agreement with the experimental data. The model was then applied to optimize the purification process through maximization of yield studying the impact of mobile phase salt concentration and pH, isocratic wash and elution length, flow rate, percent full (purity) requirement, loading density (challenge), and the use of single-step or two-step elution modes. A solution from the optimization with purity of 90% and recovery yield of 84% was selected and successfully validated, as the model could predict the recovery yield with remarkable fidelity and was able to find process conditions that led to significant enrichment. This is, to the best of our knowledge, the first case study of the application of de novo mechanistic modeling for the enrichment of full capsids in rAAV manufacturing, and it serves as demonstration of the potential of mechanistic modeling in rAAV process development.

Size and morphology of the coracoid and glenoid in pediatric and adolescent patients: implications for Latarjet procedure.

Background: Glenohumeral instability is a challenging problem in children and adolescents. For patients with anterior glenoid bone loss, the Latarjet procedure is an effective treatment option. However, concerns about coracoid size and morphology may limit its utilization within this patient population. The purpose of this study was to establish normative data on coracoid and glenoid size and morphology among a large cohort of adolescent patients and describe the anatomic relationships with demographic factors. Methods: This is a retrospective cross-sectional study of a consecutive series of 584 patients aged 12-21 years after a chest computed tomography scan for non-shoulder related trauma at a single level I trauma center. Demographic characteristics were collected from the electronic medical record, and the following coracoid anatomic measurements were obtained from computed tomography scans: coracoid length, coracoid thickness, coracoid width, glenoid height, and glenoid width. The ratio of coracoid thickness to glenoid width was calculated to estimate the percent bone loss that could be addressed with a traditional Latarjet coracoid transfer. To ensure reliability among 3 reviewers, all measured the same 25 scans and inter-rater reliability was excellent with all Kappa coefficients >0.81. The remaining scans were divided equally and assessed separately by these reviewers. Correlation coefficients were used to quantify the relationships between all anatomic measures and the age, weight, and height of individuals. Growth curves for each measurement were modeled using quantile regression with height and height∗height as predictors. Additionally, we stratified the growth curves by sex, when significant. Of the 584 subjects, 55% were male, and average age was 19 years (range 12, 21). Results: All growth curves illustrated increase anatomic size across the height range of 145-190 cm. The growth curve including all patients (Fig. 1) illustrated that the 50% percentile of median coracoid length increased from approximately 28 to 32 mm. In addition to height, sex was a significant predictor for coracoid width and glenoid width. The median coracoid width increased from approximately 9.5 to 10.2 mm for females compared to an increased width from approximately 10 to 11 mm for males. The median glenoid width for females increased from approximately 21 to 25 mm and for males the median glenoid width increased from just under 22 to 25.5 mm. Conclusions: Among children and adolescents, coracoid and glenoid size are correlated with patient height. These data can help guide patient selection for the Latarjet procedure.

Biomechanical comparison of Tibial-sided supplemental fixation techniques in Bone-Patellar Tendon-Bone anterior cruciate ligament reconstruction.

PURPOSE: The purpose of this study was to compare the biomechanical properties of a commercially available suture anchor and a screw post for supplemental tibial fixation of a bone-patellar tendon-bone (BTB) graft at time zero. We hypothesized that supplemental fixation using a suture anchor would demonstrate similar biomechanical performance in comparison with a screw post. METHODS: Sixteen fresh frozen, healthy human cadaveric knees underwent BTB autograft harvest, placement, and primary tibial-sided interference screw fixation using a standardized technique performed by a single surgeon. Specimens were randomly assigned to one of two tibial-sided supplemental fixation groups (suture anchor or screw post), yielding eight specimens in each group. Each specimen was affixed to a custom loading apparatus, with the tibial tunnel aligned in a vertical position that allowed for parallel "worst-case scenario" loading and eliminated loading variation due to tibial tunnel angle. Grafts were pretensioned to 30 N and biomechanical performance was compared with respect to cyclical loading between 50-250 N for 500 cycles at 0.5 Hz and pull-to-failure loading at 60 mm/min. RESULTS: The suture anchor and screw post supplemental constructs demonstrated similar performance with respect to all biomechanical parameters assessed, including yield strength (294.0 N [IQR 267.2-304.2 N] versus 332.1 N [IQR 313.8-350.4 N]; P = 0.079) and ultimate strength (330.1 N [IQR 306.9-418.7 N] versus 374.7 N [IQR 362.0-387.3 N]; P = 0.3798). However, of the eight original specimens in each group, one suture anchor specimen (12.5%) and six metallic screw post specimens (75%) failed during cyclical testing and were unable to undergo displacement and load to failure testing. CONCLUSION: This study provides preliminary evidence that supplemental tibial-sided fixation of a BTB ACL graft with a suture anchor has similar loading characteristics or load-to-failure strength when compared to supplemental fixation with a screw post construct. STUDY DESIGN: Laboratory Controlled Study. LEVEL OF EVIDENCE: Basic Science Study.

Outcomes after arthroscopic repair of rotator cuff tears in the setting of mild to moderate glenohumeral osteoarthritis.

BACKGROUND: Rotator cuff pathology is a very common source of shoulder pain. Similarly, osteoarthritis of the glenohumeral joint can cause shoulder pain and produce similar symptoms. Surgical management can be indicated for both pathologies, however, outcomes data is limited when examining rotator cuff repair (RCR) in the setting of glenohumeral arthritis (GHOA). Thus, this study sought to determine outcomes for patients who undergo RCR in the setting of GHOA. AIM: To evaluate if a relationship exists between outcomes of RCR in the setting of GHOA. METHODS: This was a retrospective analysis of patients who underwent arthroscopic rotator cuff repair with concurrent glenohumeral osteoarthritis between 2010-2017. Patients were stratified based on rotator cuff tear size and glenohumeral osteoarthritis severity. Cohorts were paired 1:1 with patients without glenohumeral osteoarthritis. Patients included had a minimum two year follow-up. Rate of conversion to total shoulder arthroplasty, complication rates following initial surgery, and patient-reported outcome measures were collected. RESULTS: A total of 142 patients were included. The number of patients that required total shoulder arthroplasty within two years after index surgery was low. 2/71 (2.8%) patients with GHOA, and 1/71 (1.4%) without GHOA. Following rotator cuff repair, both groups showed favorable patient-reported outcomes. CONCLUSION: Patients with glenohumeral osteoarthritis who underwent arthroscopic rotator cuff repair showed comparable outcomes to patients without glenohumeral osteoarthritis.

Conversion of anatomic total shoulder arthroplasty to reverse shoulder arthroplasty using a unique hybrid glenoid component: technique and preliminary results.

Background: Degenerative arthritis of the shoulder is a common condition that is successfully treated with anatomic total shoulder arthroplasty (TSA). Rotator cuff disease has evolved as a leading cause of failure of anatomic TSA, requiring revision to reverse shoulder arthroplasty (RSA). This revision procedure can be extremely complex, particularly if removal of a well-fixed glenoid component is necessary. This case series outlines the technique and preliminary clinical results of conversion of anatomic TSA to RSA utilizing both modular humeral and hybrid glenoid components. Methods: From July 2017 to December 2019, the senior author (PMC) performed 84 consecutive anatomic TSA procedures utilizing a modular humeral arthroplasty system and a unique hybrid glenoid component. Three cases (3/84, or 3.6%) required conversion from anatomic TSA to RSA because of postoperative traumatic rotator cuff failure. All modular revision cases were performed without humeral stem removal and with utilization of the existing, well-fixed hybrid glenoid central titanium peg as the foundation for glenoid component revision. Preoperative and postoperative American Shoulder and Elbow Surgeons scores, visual analog scale pain scores, forward flexion, and patient satisfaction were analyzed in this modular revision group. In addition, several perioperative variables including operative time, blood loss, and length of stay were compared between this modular revision group and a nonmodular anatomic TSA to RSA revision comparative cohort. Results: At an average follow-up of 24 months, average active forward flexion, postoperative American Shoulder and Elbow Surgeons scores, and visual analog scale pain scores improved significantly compared with preoperative scores in the modular revision group. All three patients were satisfied with their outcome. The average total operative time (109 minutes vs. 154 minutes, P = .02), blood loss (183 cc vs. 500 cc, P = .08), and length of hospital stay (26.3 hours vs. 36.6 hours P < .05) were lower in the modular revision group than those in a nonmodular revision cohort. Conclusion: Revision of anatomic TSA to RSA utilizing a modular humeral system and a convertible hybrid glenoid component that does not require removal of a well-fixed central titanium peg which serves as the foundation for glenoid component revision was performed efficiently, safely, and successfully in three cases. This technique results in significantly improved clinical outcomes when revision to RSA is needed while potentially decreasing perioperative complications in the revision setting.

Lateral Extra-articular Tenodesis Alters Lateral Compartment Contact Mechanics under Simulated Pivoting Maneuvers: An In Vitro Study.

BACKGROUND: There is concern that utilization of lateral extra-articular tenodesis (LET) in conjunction with anterior cruciate ligament (ACL) reconstruction (ACLR) may disturb lateral compartment contact mechanics and contribute to joint degeneration. HYPOTHESIS: ACLR augmented with LET will alter lateral compartment contact mechanics in response to simulated pivoting maneuvers. STUDY DESIGN: Controlled laboratory study. METHODS: Loads simulating a pivot shift were applied to 7 cadaveric knees (4 male; mean age, 39 ± 12 years; range, 28-54 years) using a robotic manipulator. Each knee was tested with the ACL intact, sectioned, reconstructed (via patellar tendon autograft), and, finally, after augmenting ACLR with LET (using a modified Lemaire technique) in the presence of a sectioned anterolateral ligament and Kaplan fibers. Lateral compartment contact mechanics were measured using a contact stress transducer. Outcome measures were anteroposterior location of the center of contact stress (CCS), contact force from anterior to posterior, and peak and mean contact stress. RESULTS: On average, augmenting ACLR with LET shifted the lateral compartment CCS anteriorly compared with the intact knee and compared with ACLR in isolation by a maximum of 5.4 ± 2.3 mm (P < .001) and 6.0 ± 2.6 mm (P < .001), respectively. ACLR augmented with LET also increased contact force anteriorly on the lateral tibial plateau compared with the intact knee and compared with isolated ACLR by a maximum of 12 ± 6 N (P = .001) and 17 ± 10 N (P = .002), respectively. Compared with ACLR in isolation, ACLR augmented with LET increased peak and mean lateral compartment contact stress by 0.7 ± 0.5 MPa (P = .005) and by 0.17 ± 0.12 (P = .006), respectively, at 15° of flexion. CONCLUSION: Under simulated pivoting loads, adding LET to ACLR anteriorized the CCS on the lateral tibial plateau, thereby increasing contact force anteriorly. Compared with ACLR in isolation, ACLR augmented with LET increased peak and mean lateral compartment contact stress at 15° of flexion. CLINICAL RELEVANCE: The clinical and biological effect of increased anterior loading of the lateral compartment after LET merits further investigation. The ability of LET to anteriorize contact stress on the lateral compartment may be useful in knees with passive anterior subluxation of the lateral tibia.

The Arthroscopic Surgery Skill Evaluation Tool Global Rating Scale is a Valid and Reliable Adjunct Measure of Performance on a Virtual Reality Simulator for Hip Arthroscopy.

PURPOSE: The purpose of this study is to further evaluate the construct validity and interobserver reliability of a hip arthroscopy virtual simulator using the Arthroscopic Surgery Skill Evaluation Tool (ASSET) global rating scale. METHODS: Thirty participants (23 male/7 female) completed a diagnostic arthroscopy and a loose body retrieval simulation on the VirtaMed Arthros Hip Simulator (Zurich, Switzerland) twice at a minimum of 1 week apart. Subjects consisted of 12 novices (medical students, postgraduate year [PGY] 1-2), 5 intermediate trainees (PGY3-4), 9 senior trainees (PGY5 and fellows), and 4 attending faculty. Simulator metrics were recorded and then compiled to generate a total simulator score (TSS). The loose body retrieval was graded using the ASSET scoring tool. Inter-rater and intrarater reliability for the ASSET for 2 blinded raters and construct validity of the ASSET and the TSS were calculated. Correlation between the TSS, ASSET and individual simulator metrics was determined. RESULTS: Prior simulation experience (P ≤ 0.01) correlated with higher TSS and higher ASSET, while video game experience correlated with higher TSS on the diagnostic module only (P = 0.004). There was a significant difference in ASSET score among all experience groups (P < 0.04). Novices had the lowest mean ASSET whereas experts had the highest mean ASSET with a difference of 17.4 points. Overall performance on the surgical module significantly correlated with the ASSET score (r = 0.444, P = 0.016). There was a significant positive correlation among higher ASSET and number of loose bodies retrieved, operation time, camera path and grasper path length, and percentage of cartilage injury. ASSET demonstrated excellent intrarater reliability and showed substantial or better inter-reliability in 8 of 9 domains. CONCLUSION: The VirtaMed hip arthroscopy simulator demonstrated good construct validity and excellent reliability for simulator-based metrics and ASSET score. Use of both simulator metrics and ASSET offers a more comprehensive performance assessment on hip arthroscopy simulation than either measure alone. CLINICAL RELEVANCE: As virtual reality simulation for arthroscopy becomes more commonplace in orthopaedic training, evaluation of the most effective objective and subjective measures of performance is necessary to optimize simulation training.

Lateral Extra-articular Tenodesis Reduces Anterior Cruciate Ligament Graft Force and Anterior Tibial Translation in Response to Applied Pivoting and Anterior Drawer Loads.

BACKGROUND: The biomechanical effect of lateral extra-articular tenodesis (LET) performed in conjunction with anterior cruciate ligament (ACL) reconstruction (ACLR) on load sharing between the ACL graft and the LET and on knee kinematics is not clear. PURPOSE/HYPOTHESIS: The purpose was to quantify the effect of LET on (1) forces carried by both the ACL graft and the LET and (2) tibiofemoral kinematics in response to simulated pivot shift and anterior laxity tests. We hypothesized that LET would decrease forces carried by the ACL graft and anterior tibial translation (ATT) in response to simulated pivoting maneuvers and during simulated tests of anterior laxity. STUDY DESIGN: Controlled laboratory study. METHODS: Seven cadaveric knees (mean age, 39 ± 12 years [range, 28-54 years]; 4 male) were mounted to a robotic manipulator. The robot simulated clinical pivoting maneuvers and tests of anterior laxity: namely, the Lachman and anterior drawer tests. Each knee was assessed in the following states: ACL intact, ACL sectioned, ACL reconstructed (using a bone-patellar tendon-bone autograft), and after performing LET (the modified Lemaire technique after sectioning of the anterolateral ligament and Kaplan fibers). Resultant forces carried by the ACL graft and LET at the peak applied loads were determined via superposition. ATT was determined in response to the applied loads. RESULTS: With the applied pivoting loads, performing LET decreased ACL graft force up to 80% (44 ± 12 N; P < .001) and decreased ATT of the lateral compartment compared with that of the intact knee up to 7.6 ± 2.9 mm (P < .001). The LET carried up to 91% of the force generated in the ACL graft during isolated ACLR (without LET). For simulated tests of anterior laxity, performing LET decreased ACL graft force by 70% (40 ± 20 N; P = .001) for the anterior drawer test with no significant difference detected for the Lachman test. No differences in ATT were deteced between ACLR with LET and the intact knee on both the Lachman and the anterior drawer tests (P = .409). LET reduced ATT compared with isolated ACLR on the simulated anterior drawer test by 2.4 ± 1.8 mm (P = .032) but not on the simulated Lachman test. CONCLUSION: In a cadaveric model, LET in combination with ACLR transferred loads from the ACL graft to the LET and reduced ATT with applied pivoting loads and during the simulated anterior drawer test. The effect of LET on ACL graft force and ATT was less pronounced on the simulated Lachman test. CLINICAL RELEVANCE: LET in addition to ACLR may be a suitable option to offload the ACL graft and to reduce ATT in the lateral compartment to magnitudes less than that of the intact knee with clinical pivoting maneuvers. In contrast, LET did not offload the ACL graft or add to the anterior restraint provided by the ACL graft during the Lachman test.

Correction to: At the US Epicenter of the COVID-19 Pandemic, an Orthopedic Residency Program Reorganizes.

[This corrects the article DOI: 10.1007/s11420-020-09765-5.].

Quality and Variability of Online Available Physical Therapy Protocols From Academic Orthopaedic Surgery Programs for Medial Patellofemoral Ligament Reconstruction.

BACKGROUND: Unlike the literature on anterior cruciate ligament reconstruction, studies on medial patellofemoral ligament (MPFL) reconstruction lack evidence-based guidelines regarding postoperative rehabilitation. An effective postoperative protocol may contribute greatly to a successful outcome following MPFL reconstruction, yet the quality and variability of these published protocols remain unknown. PURPOSE: To assess the quality and variability of MPFL rehabilitation protocols publicly available on the internet and associated with US academic orthopaedic programs. STUDY DESIGN: Systematic review. METHODS: All available isolated MPFL reconstruction rehabilitation protocols from US academic orthopaedic programs participating in the Electronic Residency Application Service were collected and included in this review. These protocols were evaluated for inclusion of various rehabilitation components, the timing of suggested initiation of these activities, and whether the protocol used evaluation-based guidelines. RESULTS: A total of 27 protocols were included. Of these, 25 (93%) recommended immediate postoperative bracing. Time to initiation of full weightbearing ranged from 2 to 8 weeks. The most common strengthening exercises endorsed were quadriceps sets (89%), straight-legged raise (85%), and leg press (81%). The most common proprioception exercises endorsed were balance board (41%), single-legged balance (41%), and TheraBand control (33%). The median time suggested to return to play was 17 weeks. No functional test appeared in the majority of the protocols. Of the 27 protocols, 20 (74%) used evaluation-based guidelines. CONCLUSION: There is substantial variability in content and timing across rehabilitation protocols following MPFL reconstruction. This lack of clear guidelines can cause confusion among patients, therapists, and surgeons, leading to suboptimal patient outcomes and making it difficult to compare outcomes across the literature.

Return to work after shoulder arthroplasty: a systematic review and meta-analysis.

BACKGROUND: With the rising incidence of shoulder arthroplasty, there is increasing emphasis on improving functional outcomes and ability to return to work (RTW). The purpose of this study was to determine the rate of RTW after shoulder arthroplasty. METHODS: This systematic review and meta-analysis were performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A literature search of 4 electronic databases was performed from database conception through April 2018 to identify studies reporting data on RTW after shoulder arthroplasty. The primary outcome was the rate of RTW after shoulder arthroplasty. Random-effects meta-analysis was used to pool the rate of RTW across studies. RESULTS: Seven studies were reviewed, including 447 patients at an average follow-up of 4.4 years (range, 1.0-12.6 years). The overall rate of RTW was 63.6% (95% confidence interval, 58.8%-68.2%) at a mean 2.3 months postoperatively (range, 0.3-24.0 months). RTW was significantly lower for patients with heavy-intensity occupations vs. all intensity types (61.7% vs. 67.6%; P = .04). RTW did not differ between anatomic total shoulder arthroplasty (63.4%) and hemiarthroplasty (66.1%) or reverse total shoulder arthroplasty (61.5%; P = .53). There were no significant differences in RTW among underlying diagnoses (osteoarthritis, 64.4%; cuff tear arthropathy, 65.6%; proximal humerus fracture, 69.1%; P = .41) or by workers' compensation status (61.2% vs. 65.3%; P = .41). CONCLUSIONS: A majority of patients return to work after shoulder arthroplasty at an average of 2.3 months postoperatively. Those with heavy-intensity occupation return at significantly lower rates, whereas no differences in RTW by arthroplasty type, underlying diagnosis, or workers' compensation were found.

Management of ulnar collateral ligament injury in throwing athletes: a survey of the American Shoulder and Elbow Surgeons.

BACKGROUND: Amid evidence that the number of ulnar collateral ligament (UCL) reconstructions performed annually is on the rise, there continues to be significant variation among surgeons in the management of UCL injuries. The purpose of this paper was to survey the members of the American Shoulder and Elbow Surgeons (ASES) to assess current trends related to the comprehensive treatment of athletes presenting with UCL injury. METHODS: An online survey was distributed to the active members of the ASES. The survey was composed of 3 sections assessing the demographics of the survey-takers, presenting 7 distinct fictional clinical case scenarios of athletes with UCL injury, and posing a series of more general questions about operative and nonoperative management of UCL injuries. RESULTS: There were 159 ASES members who responded to the survey (24% of the active membership); 65 respondents (40.9%) reported >15 years of clinical experience. Of the 7 case scenarios presented, a consensus was reached to indicate the patient for surgery in 4 cases. In all 7 cases, when operative management was the preferred option, a consensus was reached to perform UCL reconstruction. The preferred method of UCL reconstruction among respondents was the docking technique (66.0%); 36.3% of respondents used platelet-rich plasma in their treatment of UCL injuries. CONCLUSION: The survey presented here shows that an overall experienced and well-trained cohort of surgeons tended to agree and often reached consensus opinions on how to approach UCL injury. Professional athletes and those with complete tears were indicated for surgery by consensus, whereas opinion was more divided on how to treat partial tears or nonprofessionals.

The "Safe Zone" Technique Improves Suture Placement and Accuracy During Arthroscopic Remplissage.

In response to recent concerns about the accuracy of suture passage during arthroscopic remplissage, this study was conducted to determine whether a previously described "safe zone" technique can improve the accuracy of suture passage. A recommended safe zone technique was used for arthroscopic remplissage on 6 cadaveric specimens. The safe zone was described as a region at least 1 cm lateral and no greater than 3 cm distal to the posterolateral acromion. Results were compared with a control group of 6 specimens for which the safe zone technique was not used. For each group, 24 suture passes were performed. In the safe zone group, 83.3% (20 of 24) of sutures passed through the infraspinatus tendon. This was a significant improvement compared with the control group, in which only 25% (6 of 24) of sutures pierced the infraspinatus tendon (P<.01). In the safe zone group, 4.2% (1 of 24) of attempted suture passes were placed through the muscle or musculotendinous junction compared with 75% (18 of 24) in the control group (P<.01). Prevention of overmedialization improved significantly with the safe zone technique. In the safe zone group, both anchors had significantly more lateral (6 to 10 mm) suture passage compared with the control group (P<.01). The safe zone technique also showed greater precision of suture passes, and overall precision (SD) improved in 75% of passes. The safe zone technique significantly improved the accuracy of suture penetration into the infraspinatus tendon during arthroscopic remplissage. This reproducible method may help to prevent the reported complications of remplissage. [Orthopedics. 2017; 40(4):e598-e603.].

A comparative analysis of work-related outcomes after humeral hemiarthroplasty and reverse total shoulder arthroplasty.

BACKGROUND: The return to work of young patients undergoing shoulder arthroplasty is increasingly important. Whereas studies have shown superior outcomes of reverse total shoulder arthroplasty (RTSA) compared with humeral hemiarthroplasty (HHA), no prior literature has compared RTSA with HHA in regard to return to work. METHODS: A retrospective review of a prospectively collected shoulder arthroplasty registry was performed to analyze all patients who underwent RTSA or HHA at a single institution. A validated questionnaire evaluating return to work postoperatively was administered at baseline and at follow-up in addition to the American Shoulder and Elbow Surgeons and visual analog scale (VAS) pain surveys. RESULTS: The study included 40 RTSA and 41 HHA patients. The average age at surgery was 68.6 years in the RTSA group and 60.8 years in the HHA group (P < .001). Postoperatively, 65% of RTSA patients returned to work compared with 70.7% of HHA patients (P = .64). There was no significant difference in the time to return to work between the RTSA (2.3 months) and HHA (3.1 months) groups (P = .46). Both groups had statistically significant improvements in both the American Shoulder and Elbow Surgeons and VAS scores. The improvement in pain on the VAS for patients undergoing RTSA (-5.6) trended toward significance compared with HHA (-4.2) (P = .056). CONCLUSION: Roughly two-thirds of patients undergoing either HHA or RTSA were able to return to work postoperatively, with no significant difference found between the 2 groups in terms of time to return to work, despite that patients undergoing RTSA were significantly older.

Incidence and Epidemiology of Foot and Ankle Injuries in Elite Collegiate Athletes.

BACKGROUND: Foot and ankle injuries are increasing in competitive professional and collegiate athletics. Many of these injuries result in considerable missed time from sports and often require surgical intervention. To develop and implement effective practice participation strategies, return-to-play protocols, and injury prevention programs, an understanding of injury trends and epidemiology is vital. PURPOSE: This study aimed to evaluate the incidence of foot and ankle injuries in elite athletes participating in 37 sports at a single National Collegiate Athletics Association (NCAA) Division 1 institution. STUDY DESIGN: Descriptive epidemiological study. METHODS: We evaluated the injury records of all varsity sports at a single NCAA Division 1 athletics program, including 1076 athletes participating in 37 sports. Detailed injury data were prospectively collected in a secure electronic database over a 2-year period. We reviewed the database for all foot/ankle injuries. Inclusion criteria were any foot/ankle injury that was sustained during an NCAA-sanctioned event and subsequently received medical treatment. Independent variables included athlete and injury demographics, missed days, physician visits, imaging results, and whether the injury required surgery. Injury incidence, relative frequency distributions, and sample proportions were dependent metrics for this investigation. RESULTS: During the study period, a total of 3861 total musculoskeletal injuries were recorded. There were 1035 foot/ankle injuries (27%). Of all foot/ankle injuries, 21% (218 of 1035) caused the athlete to miss at least 1 day of participation, with an average of 12.3 days of time loss from sport. Furthermore, 27% of athletes with foot/ankle injuries were referred for office evaluation by a physician, and 84% of these required radiologic imaging. The overall injury incidence rate was 3.80 per 1000 athlete-exposures (AEs). The 4 sports with the highest incidence rate (>75th percentile) were women's gymnastics, women's cross-country, women's soccer, and men's cross country. The most frequently occurring foot/ankle injuries were ankle ligament injuries, tendinopathies or fasciopathies, and bone stress injuries. CONCLUSION: The prevalence of foot/ankle injury in a large NCAA Division 1 athletics program was 27% of total musculoskeletal injuries over a 2-year period, with 21% of these injuries resulting in missed time. There were significantly higher foot and ankle injury incidence rates and more missed time in female athletes and women's sports.

New Joints, Same Old Weight: Weight Changes After Total Hip and Knee Arthroplasty.

Obesity is a well-known risk factor for postoperative complications following total joint arthroplasty. However, because the operation is often successful, orthopedic surgeons continue to operate on obese individuals, and many surgeons do so under the assumption that patients will lose weight after they are able to walk and exercise without pain. In this article, we review a recent study by Ast et al., who performed a retrospective review, using a single-center institutional registry, to determine (1) whether patients do actually lose weight after total hip and/or total knee arthroplasty, (2) whether there are predictors of postoperative weight change, and (3) whether postoperative weight changes affect patient-reported clinical outcomes. The principle conclusion was that most patients maintained their body mass index (BMI) after total hip and total knee arthroplasty (73 and 69%, respectively). However, patients undergoing total knee arthroplasty, patients who had a higher preoperative BMI, and female patients were more likely to lose weight postoperatively. When examined in the context of the current literature, this study provides valuable information for the preoperative counseling of total joint arthroplasty candidates, especially in the setting of obesity.

Viscoelastic properties of common suture material used for rotator cuff repair and arthroscopic procedures.

PURPOSE: The purpose of this study was to evaluate the viscoelastic properties of 5 suture materials, commonly used in arthroscopic rotator cuff repairs, when subjected to physiological loads. METHODS: We evaluated 5 commercially available No. 2 sutures undergoing both creep and cyclic testing in both dry air and phosphate-buffered saline solution (PBS) maintained at 37°C. The selected sutures were MagnumWire (ArthroCare, Austin, TX), Ethibond (Ethicon, Somerville, NJ), FiberWire (Arthrex, Naples, FL), Orthocord (DePuy, Warsaw, IN), and Force Fiber (Tornier, Bloomington, MN). RESULTS: Regarding creep testing, in the PBS test environment, FiberWire showed the greatest stiffness (71.1 ± 2.1 N/mm), the smallest initial extension at the 60-N load (1.10 ± 0.04 mm), and the smallest amount of creep (0.57 ± 0.01 mm). Orthocord showed the smallest amount of relaxed elongation in PBS (0.73 ± 0.11 mm). Regarding cyclic testing, in the PBS testing environment, Ethibond exhibited the smallest dynamic creep (0.28 ± 0.02 mm), FiberWire displayed the smallest peak-to-peak displacement (0.17 ± 0.00 mm), and Orthocord showed the smallest amount of relaxed elongation after cyclic loading (0.63 ± 0.11 mm). CONCLUSIONS: FiberWire consistently displayed more extreme viscoelastic properties--greater stiffness and less extensibility--than the other suture types studied. Orthocord showed the smallest amount of relaxed elongation in both testing environments. Differences in testing environment affect the behavior of each suture type. Testing in physiologically approximating conditions such as PBS maintained at 37°C is warranted. CLINICAL RELEVANCE: Although many other factors affect the success of rotator cuff repairs, the viscoelastic properties of sutures may be a useful predictor of suture performance.

Biomechanical comparison of an all-soft suture anchor with a modified Broström-Gould suture repair for lateral ligament reconstruction.

BACKGROUND: Anatomic repair is indicated for patients who have recurrent lateral ankle instability despite nonoperative measures. HYPOTHESIS: There is no difference in repair stiffness, failure torque, or failure angle between specimens repaired with all-soft suture anchors versus the modified Broström-Gould technique with sutures only. STUDY DESIGN: Controlled laboratory study. METHODS: In 10 matched pairs of human cadaveric ankles, the anterior talofibular ligament (ATFL) was incised from its origin on the fibula. After randomization, 1 ankle was repaired to its anatomic insertion using two 1.4-mm JuggerKnot all-soft suture anchors; the other ankle was repaired with a modified Broström-Gould technique using 2-0 FiberWire. All were augmented using the inferior extensor retinaculum. All ankles were mounted to the testing machine in 20° of plantar flexion and 15° of internal rotation and loaded to failure after the repair. Stiffness, failure torque, and failure angle were recorded and compared using a paired Student t test with a significance level set at P < .05. RESULTS: There was no significant difference in failure torque, failure angle, or stiffness. No anchors pulled out of bone. The primary mode of failure was pulling through the ATFL tissue. CONCLUSION: There was no statistical difference in strength or stiffness between a 1.4-mm all-soft suture anchor and a modified Broström-Gould repair with 2-0 FiberWire. The primary mode of failure was at the tissue level rather than knot failure or anchor pullout. CLINICAL RELEVANCE: The particular implant choice (suture only, tunnel, anchor) in repairing the lateral ligament complex may not be as important as the time to biological healing. The suture-only construct as described in the Broström-Gould repair was as strong as all-soft suture anchors, and the majority of the ankles failed at the tissue level. For those surgeons whose preference is to use anchor repair, this novel all-soft suture anchor may be an alternative to other larger anchors, as none failed by pullout.

Use of patient-reported outcome measures in foot and ankle research.

BACKGROUND: In the orthopaedic literature, there is a wide range of clinical outcome measurement tools that have been used in evaluating foot and ankle procedures, disorders, and outcomes, with no broadly accepted consensus as to which tools are preferred. The purpose of this study was to determine the frequency and distribution of the various outcome instruments used in the foot and ankle literature, and to identify trends for use of these instruments over time. METHODS: We conducted a systematic review of all original clinical articles reporting on foot and/or ankle topics in six orthopaedic journals over a ten-year period (2002 to 2011). All clinical patient-reported outcome rating instruments used in these articles were recorded, as were study date, study design, clinical topic, and level of evidence. RESULTS: A total of 878 clinical foot and ankle articles that used at least one patient-reported outcome measure were identified among 16,513 total articles published during the ten-year period. There were 139 unique clinical outcome scales used, and the five most popular scales (as a percentage of foot/ankle outcome articles) were the American Orthopaedic Foot & Ankle Society (AOFAS) scales (55.9%), visual analog scale (VAS) for pain (22.9%), Short Form-36 (SF-36) Health Survey (13.7%), Foot Function Index (FFI) (5.5%), and American Academy of Orthopaedic Surgeons (AAOS) outcomes instruments (3.3%). The majority of articles described Level-IV studies (70.1%); only 9.4% reported Level-I studies. CONCLUSIONS: A considerable variety of outcome measurement tools are used in the foot and ankle clinical literature, with a small proportion used consistently. The AOFAS scales continue to be used at a high rate relative to other scales that have been validated. Data from the present study underscore the need for a paradigm shift toward the use of consistent, valid, and reliable outcome measures for studies of foot and ankle procedures and disorders. It is not clear which existing validated outcome instruments will emerge as widely used and clinically meaningful. CLINICAL RELEVANCE: These data support the need for a paradigm shift toward the consistent use of valid and reliable outcome measures for foot and ankle clinical research.