Derrick M. Knapik

Biologic and Synthetic Grafts in the Reconstruction of Large to Massive Rotator Cuff Tears.

Rotator cuff injuries are common in both young and elderly patients. Despite improvements in instrumentation and surgical techniques, the failure rates following tendon reconstruction remain unacceptably high. To improve outcomes, graft patches have been developed to provide mechanical strength and to furnish a scaffold for biologic growth across the delicate tendon-bone junction. Although no patch effectively re-creates the structured, highly organized system of prenatal tendon development, augmenting rotator cuff repair may help restore native tendon-to-bone attachment while reproducing the mechanical and biologic properties of native tendon. An understanding of biologically and synthetically derived grafts, along with knowledge of the preliminary data available regarding their combined use with growth factors and stem cells, is needed to improve management and treatment outcomes. The current literature has not been consistent in showing patch augmentation to be beneficial over traditional repair, but novel scaffolding materials may help facilitate rotator cuff tendon repair that is histologically and biomechanically comparable to native tendon.

Differences in Medial and Lateral Posterior Tibial Slope An Osteological Review of 1090 Tibiae Comparing Age, Sex, and Race

Background: Injuries to the anterior cruciate ligament (ACL) are common, and a number of knee morphological variables have been identified as risk factors for an ACL injury, including the posterior tibial slope (TS). However, limited data exist regarding innate population differences in the TS. Purpose: To (1) establish normative values for the medial and lateral posterior TS; (2) determine what differences exist between ages, sexes, and races; and (3) determine how internal or external tibial rotation (as occurs during sagittal knee motion) influences the stereotactic perception of the TS. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 545 cadaveric specimens (1090 tibiae) were obtained from the Hamann-Todd osteological collection. Specimens were leveled in the coronal, sagittal, and axial planes using a digital laser. Virtual representations of each bone were created with a 3-dimensional digitizer apparatus. The TS of the medial and lateral tibial plateaus were measured using techniques adapted from previous radiographic protocols. Medial and lateral TS were then again measured on 200 tibiae that were internally and externally rotated by 10° (axially). Results: The mean (±SD) medial TS was 6.9° ± 3.7° posterior, which was greater than the mean lateral TS of 4.7° ± 3.6° posterior (P < .001). Neither the medial nor lateral TS changed with age. Women had a greater mean TS compared with men on both the medial (7.5° ± 3.8° vs 6.8° ± 3.7°, respectively; P = .03) and lateral (5.2° ± 3.5° vs 4.6° ± 3.5°, respectively; P = .04) sides. Black specimens had a greater mean medial TS (8.7° ± 3.6° vs 5.8° ± 3.3°, respectively; P < .001) and lateral TS (5.9° ± 3.3° vs 3.8° ± 3.5°, respectively; P < .001) compared with white specimens. Axial rotation was shown to increase the perception of the medial and lateral TS (P < .001). Conclusion: The medial TS was shown to be greater than the lateral TS. Important sex- and race-based differences exist in the TS. This study also highlights the role of axial rotation in measuring the TS.

Outcomes of Nonoperative Pediatric Medial Humeral Epicondyle Fractures With and Without Associated Elbow Dislocation.

Background: Medial epicondyle fractures may occur in isolation or with associated elbow dislocation. In the absence of open fracture or fragment incarceration, nonoperative management with immobilization has been shown to result in generally successfully outcomes comparable with those reported after surgical fixation. However, no comparative investigation has assessed outcomes after nonoperative treatment based on the presence or absence of elbow dislocation. Methods: A systematic review was conducted investigating all studies in the literature reporting nonoperative outcomes for isolated medial epicondyle fractures and fracture-dislocations. Databases included in this review were PubMed, Biosis Preview, SPORTDiscus, PEDro, and EMBASE. We sought to evaluate results related to the incidence and outcomes of bony nonunion and the incidence of elbow stiffness, pain, ulnar neuropathy, cubitus valgus deformity, and laxity between isolated fractures of the medial epicondyle and fracture-dislocations. Results: Review of the literature yielded 7 studied meeting appropriate inclusion and exclusion criteria, comprising 81 total patients (n=42 patients with fracture-dislocations, n=39 patients with isolated fracture). Bony nonunion occurred in 69% (n=29) of patients with fracture-dislocation versus 49% (n=19) with isolated fractures (P=0.11); however, both groups had minimal clinical or functional disabilities at final follow-up. Decreased elbow flexion and extension range of motion were significantly more frequent after fracture-dislocation than isolated fractures [43% (n=18) vs. 15% (n=6), respectively, P=0.01], while patients rarely demonstrated pain, ulnar neuropathy, or deformity in the presence or absence of dislocation. Conclusions: In the absence of absolute surgical indication, nonoperative management of isolated medical epicondyle fractures with or without concomitant elbow dislocation seems to be successful with few long-term complications leading to functional disability. However, increased rates of nonunion, elbow stiffness, and elbow laxity may occur with fracture-dislocations, and merit further study with validated functional outcome scores. Further comparative studies are necessary to determine the true indications and outcomes in nonoperatively managed medial epicondyle fractures. Level of Evidence: Level II—systematic review of level-II or level-I studies with inconsistent results.

Prevalence and Management of Coracoid Fracture Sustained During Sporting Activities and Time to Return to Sport: A Systematic Review:

Background: Coracoid fractures sustained during sporting activities are rare. Previous reports are limited to individual case reports, small case series, and retrospective analyses. Purpose: To systematically review the literature and identify coracoid fractures sustained during sporting activities to determine fracture prevalence, sporting activities/mechanisms, management, and time to return to sport. Study Design: Systematic review. Methods: A systematic review was conducted investigating all studies in the literature published between January 1970 and April 2017 that reported on athletes sustaining coracoid fractures during sporting activity. The systematic review followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines and used PubMed, Biosis Previews, SPORTDiscus, PEDro, and EMBASE databases. Inclusion criteria were studies detailing (1) coracoid fractures with reported sporting activity causing injury, (2) fracture management (operative vs nonoperative), and (3) patient outcome. Exclusion criteria were (1) studies concerning fractures secondary to nonsporting activities (mechanical falls, motor vehicle accidents) and (2) studies not reporting fracture management or patient outcomes. Sporting activities, the presence or absence of associated acromioclavicular (AC) joint injury, fracture management, patient outcomes, and time to return to sport were analyzed. Results: A total of 21 cases of coracoid fractures sustained during sporting activity were identified; acute trauma was responsible for 71% (n = 15/21) of fractures, and the remaining injuries were secondary to fatigue fractures. Concurrent AC joint injury was present in 60% (n = 9/15) of athletes sustaining acute trauma and in no athlete with fatigue fractures. Fractures were treated conservatively in 76% (n = 16/21) of patients, with only 19% (n = 3/16) of athletes reporting complications. Mean overall time to return to sport was 2.8 ± 2.0 months; no significant differences in return to sport were noted in athletes with traumatic versus fatigue fractures or those with or without AC joint injury. Conclusion: Coracoid fractures secondary to sporting activities are rare, occurring primarily from direct trauma with associated AC joint injury, and are treated successfully with nonoperative management. No difference in return to sport was found regardless of fracture mechanism, treatment, or the presence of associated AC joint injury.

Conservative Management of Minimally Displaced (≤2 mm) Fractures of the Lateral Humeral Condyle in Pediatric Patients: A Systematic Review.

Background: Fractures to the lateral humeral condyle are common in the pediatric population and can lead to complications related to displacement of the fracture fragment. The ideal treatment for minimally displaced fractures (measuring ⩽2 mm) is controversial. Methods: A systematic review was performed identifying and evaluating studies related to displacement of lateral humeral condyle fractures in pediatric patients. Databases included in this review were PubMed, Biosis Preview, SPORTDiscus, PEDro, and EMBASE. We investigated the rate of subsequent displacement for minimally displaced fractures following immobilization, the time span in which fracture displacement occurs, and the complications related to displacement despite immobilization. Results: Our review of the literature found 6 studies that matched the search criteria. The risk of subsequent displacement in minimally displaced fractures initially treated with immobilization was 14.9% with fracture displacement typically occurring within the first week following injury. Malunion, nonunion, and loss of motion were the most commonly identified complications following subsequent displacement. Conclusions: For minimally displaced fractures of the lateral humeral condyle, appropriate diagnosis of fracture stability and fracture displacement with close radiographic follow-up 1 week following injury dictate the success of conservative management. Level of Evidence: Level II—systematic review of level-II or level-I studies with inconsistent results.

Effects of PDGF-BB delivery from heparinized collagen sutures on the healing of lacerated chicken flexor tendon in vivo

Flexor tendon lacerations are traditionally repaired by using non-absorbable monofilament sutures. Recent investigations have explored to improve the healing process by growth factor delivery from the sutures. However, it is difficult to conjugate growth factors to nylon or other synthetic sutures. This study explores the performance of a novel electrochemically aligned collagen suture in a flexor tendon repair model with and without platelet derived growth factor following complete tendon laceration in vivo. Collagen suture was fabricated via electrochemical alignment process. Heparin was covalently bound to electrochemically aligned collagen sutures (ELAS) to facilitate affinity bound delivery of platelet-derived growth factor-BB (PDGF-BB). Complete laceration of the flexor digitorum profundus in the third digit of the foot was performed in 36 skeletally mature White Leghorn chickens. The left foot was used as the positive control. Animals were randomly divided into three groups: control specimens treated with standard nylon suture (n=12), specimens repaired with heparinated ELAS suture without PDGF-BB (n=12) and specimens repaired with heparinated ELAS suture with affinity bound PDGF-BB (n=12). Specimens were harvested at either 4weeks or 12weeks following tendon repair. Differences between groups were evaluated by the degree of gross tendon excursion, failure load/stress, stiffness/modulus, absorbed energy at failure, elongation/strain at failure. Quantitative histological scoring was performed to assess cellularity and vascularity. Closed flexion angle measurements demonstrated no significant differences in tendon excursion between the study groups at 4 or 12weeks. Biomechanical testing showed that the group treated with PDGF-BB bound heparinated ELAS suture had significantly higher stiffness and failure load (p<0.05) at 12-weeks relative to both heparinated ELAS suture and nylon suture. Similarly, the group treated with PDGF-BB bound suture had significantly higher ultimate tensile strength and Youngs modulus (p<0.05) at 12-weeks relative to both ELAS suture and nylon suture. Compared to nylon controls, heparinized ELAS with PDGF-BB improved biomechanics and vascularity during tendon healing by 12-weeks following primary repair. The ability of ELAS to deliver PDGF-BB to the lacerated area of tendon presents investigators with a functional bioinductive platform to improve repair outcomes following flexor tendon repair. STATEMENT OF SIGNIFICANCE A high strength aligned collagen suture was fabricated via linear electrocompaction and heparinized for prolonged delivery of PDFG-BB. When it was used to suture a complete lacerated flexor tendon in a chicken model controlled release of the PDGF-BB improved the strength of treated tendon after 12 weeks compared to tendon sutured with commercial nylon suture. Furthermore, Collagen suture with affinity bound PDGF-BB enhanced the vascularization and remodeling of lacerated tendon when it compare to synthetic nylon suture. Overall, electrocompacted collagen sutures holds potential to improve repair outcome in flexor tendon surgeries by improving repair strength and stiffness, vascularity, and remodeling via sustained delivery of the PDGF-BB. The bioinductive collagen suture introduces a platform for sustained delivery of other growth factors for a wide-array of applications.

Prevalence and Impact of Hip Arthroscopic Surgery on Future Participation in Elite American Football Athletes

Background: Intra-articular injuries to the hip in elite athletes represent a source of significant pain and disability. Hip arthroscopic surgery has become the gold standard for the treatment of disorders involving the hip joint. Purpose: To examine the incidence of and abnormalities treated with hip arthroscopic surgery as well as the impact on future participation in American football athletes invited to the National Football League (NFL) Scouting Combine with a history of hip arthroscopic surgery. Study Design: Cohort study; Level of evidence, 3. Methods: Athletes invited to the NFL Combine from 2012 to 2015 were evaluated for a history of hip arthroscopic surgery. Athlete demographics, imaging findings, and physical examination results were gathered using the NFL Combine database. Information on prospective participation in the NFL with regard to draft status, games played, games started, and current status was gathered using publicly available databases and compared against all other athletes participating in the combine. Results: Fourteen athletes (15 hips) had a history of arthroscopic hip surgery. Acetabular labral tears were treated in 93% (14 hips), with femoroacetabular impingement decompression performed in 33% (5 hips). Compared with athletes who had no history of hip arthroscopic surgery, those undergoing arthroscopic surgery did not possess a lower likelihood of being drafted (66% vs 71%, respectively; P = .78) or of being on an active roster (52% vs 43%, respectively; P = .44) after their first season in the NFL. Moreover, there was no significant difference in the number of regular-season games played (10.9 ± 4.8 with arthroscopic surgery vs 11.0 ± 5.1 without; P = .96) or started (7.0 ± 3.6 with arthroscopic surgery vs 7.1 ± 5.3 without; P = .98). Conclusion: American football athletes invited to the NFL Combine with a history of hip arthroscopic surgery were not at risk for diminished participation when compared with all other athletes during their first season in the NFL.

Prevalence and impact of glenoid augmentation in American football athletes participating in the national football league scouting combine

Background: Bony augmentation of the anterior glenoid is used in athletes with recurrent shoulder instability and bone loss; however, the prevalence and impact of repair in elite American football athletes are unknown. Purpose: To evaluate the prevalence and impact of glenoid augmentation in athletes invited to the National Football League (NFL) Scouting Combine from 2012 to 2015. Study Design: Case series; Level of evidence, 4. Methods: A total of 1311 athletes invited to the NFL Combine from 2012 to 2015 were evaluated for history of either Bristow or Latarjet surgery for recurrent anterior shoulder instability. Athlete demographics, surgical history, imaging, and physical examination results were recorded using the NFL Combine database. Prospective participation data with regard to draft status, games played, games started, and status after the athletes’ first season in the NFL were gathered using publicly available databases. Results: Surgical repair was performed on 10 shoulders in 10 athletes (0.76%), with the highest prevalence in defensive backs (30%; n = 3). Deficits in shoulder motion were exhibited in 70% (n = 7) of athletes, while 40% (n = 4) had evidence of mild glenohumeral arthritis and 80% demonstrated imaging findings consistent with a prior instability episode (8 labral tears, 2 Hill-Sachs lesions). Prospectively, 40% (n = 4) of athletes were drafted into the NFL. In the first season after the combine, athletes with a history of glenoid augmentation were not found to be at significant risk for diminished participation with regard to games played or started when compared with athletes with no history of glenoid augmentation or athletes undergoing isolated shoulder soft tissue repair. After the conclusion of the first NFL season, 60% (n = 6 athletes) were on an active NFL roster. Conclusion: Despite being drafted at a lower rate than their peers, there were no significant limitations in NFL participation for athletes with a history of glenoid augmentation when compared with athletes without a history of shoulder surgery or those with isolated soft tissue shoulder repair. Glenohumeral arthritis and advanced imaging findings of labral tearing and Hill-Sachs lesions in elite American football players with a history of glenoid augmentation did not significantly affect NFL participation 1 year after the combine.

National Incidence of Reportable Quality Metrics in the Knee Arthroplasty Population

BACKGROUND The Centers for Medicare and Medicaid Services (CMS) characterizes adverse quality events in the inpatient setting as patient safety indicators (PSI). The incidence of PSI has not been quantified in the total knee arthroplasty (TKA) population. METHODS All patients in the Nationwide Inpatient Sample who underwent primary TKA during an inpatient episode in 2013 were identified using International Classification of Disease, Ninth Revision, Clinical Modification codes. The incidence of PSI was determined using the International Classification of Disease, Ninth Revision diagnosis code algorithms used by CMS. Multivariable logistic regression was used to determine significant associations between patient level covariates (demographics, comorbidities, and hospital characteristics) and the risk of experiencing one or more PSI after TKA. RESULTS We identified 132,453 primary TKA patients in the Nationwide Inpatient Sample in 2013. We estimated the national incidence rate of experiencing one or more PSI as 0.98%. After adjusting for patient demographics and hospital characteristics, we found that relative to Medicaid/self-pay patients, neither Medicare nor privately insured patients faced significantly different risk of experiencing one or more PSI after TKA. However, alcohol abuse, deficiency anemia, congestive heart failure, coagulopathy, and electrolyte imbalance were associated with increased risk of experiencing one or more PSI after TKA. CONCLUSION The national incidence of PSI among TKA patients was lower than has been reported in other surgical populations. CMS uses the incidence of adverse quality events (measured using PSI) in part to determine hospital reimbursement. As value-based payment becomes more widely adopted in the United States, initiatives designed to eliminate and reduce PSI incidence can benefit vulnerable patient populations, physicians, and hospital systems.

National Incidence of Patient Safety Indicators in the Total Hip Arthroplasty Population

BACKGROUND The Centers for Medicare & Medicaid Services use the incidence of patient safety indicators (PSIs) to determine health care value and hospital reimbursement. The national incidence of PSI has not been quantified in the total hip arthroplasty (THA) population, and it is unknown if patient insurance status is associated with PSI incidence after THA. METHODS All patients in the Nationwide Inpatient Sample (NIS) who underwent THA in 2013 were identified using the International Classification of Diseases, Ninth Revision, Clinical Modification codes. The incidence of PSI was determined using the International Classification of Diseases, Ninth Revision, diagnosis code algorithms published by the Centers for Medicare & Medicaid Services and the Agency for Healthcare Research and Quality. The association of insurance status and the incidence of PSI during the inpatient episode was determined by comparing privately insured and Medicare patients with Medicaid/self-pay patients using a logistic regression model that controlled for patient demographics, patient comorbidities, and hospital characteristics. RESULTS In 2013, the NIS included 68,644 hospitalizations with primary THA performed during the inpatient episode. During this period, 429 surgically relevant PSI were recorded in the NIS. The estimated national incidence rate of PSI after primary THA was 0.63%. In our secondary analysis, the privately insured cohort had significantly lower odds of experiencing one or more PSIs relative to the Medicaid/self-pay cohort (odds ratio, 0.47; 95% confidence interval, 0.29-0.76). CONCLUSION The national incidence of PSI among THA patients is relatively low. However, primary insurance status is associated with the incidence of one or more PSIs after THA. As value-based payment becomes more widely adopted in the United States, quality benchmarks and penalty thresholds need to account for these differences in risk-adjustment models to promote and maintain access to care in the underinsured population.