Cells Remain Viable When Collected With an In-Line-Suction Tissue Collector From Byproducts of Anterior Cruciate Ligament Reconstruction Surgery

Purpose

To investigate the viability of cells collected with an in-line-suction autologous tissue collector from the tissue byproducts of arthroscopic anterior cruciate ligament (ACL) reconstruction, to characterize cells from different tissue types, and to identify mesenchymal stem cells.

Methods

Patients aged 14 to 50 years with ACL injuries requiring arthroscopic reconstruction surgery were offered enrollment and screened for participation. In total, 12 patients were enrolled in the descriptive laboratory study. Arthroscopic byproduct tissue was collected with an in-line-suction autologous tissue collector from 4 intraoperative collection sites for each patient: ACL stump, ACL fat pad, notchplasty debris, and tunnel drilling debris. All tissue samples were digested using collagenase, and the derived cellular populations were analyzed in vitro, characterizing cellular viability, proliferative potential, qualitative multipotent differentiation capacity, and cell-surface marker presence.

Results

An equivalent mass of arthroscopic byproduct tissue was taken from each of the 4 intraoperative collection sites (1.12-1.61 g, P = .433), which all showed an average viability of at least 99.95% and high average total nucleated cells (≥1.37 × 107 cells/mL). No significant differences in collected mass (P = .433), cellular viability (P = .880), or total nucleated cells (P = .692) were observed between the 4 byproduct tissues. The byproduct tissues did exhibit significant differences in monocyte (P = .037) and red blood cell (P = .038) concentrations, specifically with greater values present in the ACL stump tissue. Cells from all byproduct tissues adhered to plastic cell culture flasks. Significant differences were found between colony-forming unit fibroblast counts of the 4 byproduct tissues when plated at 106 (P = .003) and 103 (P = .016) cells as the initial seeding density. There was a significant relationship found between both the starting concentration (χ2 = 32.7, P < .001) and the byproduct tissue type (χ2 = 30.4, P < .001) to the presence of ≥80% confluency status at 10 days. Cells obtained from all 4 byproduct tissues qualitatively showed positive tri-lineage (adipocyte, osteoblast, chondroblast) differentiation potential compared with negative controls under standardized in vitro differentiation conditions. Cells derived from all 4 byproduct tissues expressed cell-surface antigens CD105+, CD73+, CD90+, CD45-, CD14-, and CD19- (>75%), and did not express CD45 (<10%). There were no statistically significant differences in cell-surface antigens between the four byproduct tissues.

Conclusions

This descriptive laboratory study demonstrated that cells derived from arthroscopic byproduct tissues of ACL reconstruction remain viable when collected with an in-line-suction autologous tissue collector and these cells meet the ISCT criteria to qualify as mesenchymal stem cells.

Clinical Relevance

It is known that viable mesenchymal stem cells reside in byproduct tissue of anterior cruciate ligament reconstruction surgery (ACLR). Practical methods to harvest these cells at the point of care require further development. This study validates the use of an in-line-suction autologous tissue collector for the harvest of viable mesenchymal stem cells after ACLR.

Osteochondral Regeneration in the Knee Joint with Autologous Peripheral Blood Stem Cells plus Hyaluronic Acid after Arthroscopic Subchondral Drilling: Report of Five Cases

BACKGROUND

Treatment of osteochondral defects (OCDs) of the knee joint remains challenging. The purpose of this study was to evaluate the clinical and radiological results of osteochondral regeneration following intra-articular injections of autologous peripheral blood stem cells (PBSC) plus hyaluronic acid (HA) after arthroscopic subchondral drilling into OCDs of the knee joint.

CASE PRESENTATION

Five patients with OCDs of the knee joint are presented. The etiology includes osteochondritis dissecans, traumatic knee injuries, previously failed cartilage repair procedures involving microfractures and OATS (osteochondral allograft transfer systems). PBSC were harvested 1 week after surgery. Patients received intra-articular injections at week 1, 2, 3, 4, and 5 after surgery. Then at 6 months after surgery, intra-articular injections were administered at a weekly interval for 3 consecutive weeks. These 3 weekly injections were repeated at 12, 18 and 24 months after surgery. Each patient received a total of 17 injections. Subjective International Knee Documentation Committee (IKDC) scores and MRI scans were obtained preoperatively and postoperatively at serial visits. At follow-ups of >5 years, the mean preoperative and postoperative IKDC scores were 47.2 and 80.7 respectively (p = 0.005). IKDC scores for all patients exceeded the minimal clinically important difference values of 8.3, indicating clinical significance. Serial MRI scans charted the repair and regeneration of the OCDs with evidence of bone growth filling-in the base of the defects, followed by reformation of the subchondral bone plate and regeneration of the overlying articular cartilage.

CONCLUSION

These case studies showed that this treatment is able to repair and regenerate both the osseous and articular cartilage components of knee OCDs.

Augmentation of ACL Autograft Reconstruction With an Amnion Collagen Matrix Wrap and Bone Marrow Aspirate Concentrate: A Pilot Randomized Controlled Trial With 2-Year Follow-up

Background

It is theorized that the lack of a synovial lining after anterior cruciate ligament (ACL) injury and ACL reconstruction (ACLR) contributes to slow ligamentization and possible graft failure. Whether graft maturation and incorporation can be improved with the use of a scaffold requires investigation.

Purpose

To evaluate the safety and efficacy of wrapping an ACL autograft with an amnion collagen matrix and injecting bone marrow aspirate concentrate (BMAC), quantify the cellular content of the BMAC samples, and assess 2-year postoperative patient-reported outcomes.

Study Design

Randomized controlled trial; Level of evidence, 2.

Methods

A total of 40 patients aged 18 to 35 years who were scheduled to undergo ACLR were enrolled in a prospective single-blinded randomized controlled trial with 2 arms based on graft type: bone-patellar tendon-bone (BTB; n = 20) or hamstring (HS; n = 20). Participants in each arm were randomized into a control group who underwent standard ACLR or an intervention group who had their grafts wrapped with an amnion collagen matrix during graft preparation, after which BMAC was injected under the wrap layers after implantation. Postoperative magnetic resonance imaging (MRI) mapping/processing yielded mean T2* relaxation time and graft volume values at 3, 6, 9, and 12 months. Participants completed the Single Assessment Numeric Evaluation Score, Knee injury and Osteoarthritis Outcome Score, and pain visual analog scale. Statistical linear mixed-effects models were used to quantify the effects over time and the differences between the control and intervention groups. Adverse events were also recorded.

Results

No significant differences were found at any time point between the intervention and control groups for BTB T2* (95% CI, -1.89 to 0.63; P = .31), BTB graft volume (95% CI, -606 to 876.1; P = .71), HS T2* (95% CI, -2.17 to 0.39; P = .162), or HS graft volume (95% CI, -11,141.1 to 351.5; P = .28). No significant differences were observed between the intervention and control groups of either graft type on any patient-reported outcome measure. No adverse events were reported after a 2-year follow-up.

Conclusion

In this pilot study, wrapping a graft with an amnion collagen matrix and injecting BMAC appeared safe. MRI T2* values and graft volume of the augmented ACL graft were not significantly different from that of controls, suggesting that the intervention did not result in improved graft maturation.

Registration

NCT03294759 (ClinicalTrials.gov identifier).

Blood Flow Restriction Using a Pneumatic Tourniquet Is Not Associated With a Cellular Systemic Response

Purpose

The purpose of this study was to determine the effects of blood flow restriction (BFR) using a pneumatic tourniquet on CD34⁺ cells, platelets, white blood cells, neutrophils, lymphocytes, lactate, and glucose compared with standard exercise.

Methods

Fifteen healthy volunteers (8 males and 7 females, 28.6 ± 3.6 years old) who were able to perform the exercise sessions on a VersaClimber participated. Participants were randomized to undergo an experimental (EXP) occluded testing session using the pneumatic tourniquets on all 4 extremities and a control (CON) session. The exercise protocol concluded after 9 minutes or when participants reached a rating of perceived exertion of 20. Blood draws were performed before testing and immediately after the exercise session. Blood analysis consisted of complete blood counts as well as flow cytometry to measure peripheral CD34⁺ counts as a marker for hematopoietic progenitor cells (HPCs).

Results

A significant increase from before to after exercise values was observed in both the EXP and CON groups with CD34⁺, WBC counts, platelets, and lymphocytes; however, no differences existed between EXP and CON groups for any variable. CD34⁺ increased in the EXP (3.1 ± 1.6 vs. 4.3 ± 1.8 cells · L^–1; P < .001) and CON (3.3 ± 1.9 vs. 4.4 ± 1.4 cells · L^–1; P < .001) sessions. White blood cells also significantly increased in both the EXP (7.8 ± 1.4 vs. 11.8 ± 2.5 K · L^–1 K · L^–1; P < .001) and CON (7.5 ± 1.8 vs. 11.3 ± 3.0 K · L^–1; P < .001) sessions. Platelets also increased in both the EXP (258.6 ± 52.5 vs. 309.9 ± 52.7 K · L^–1; P < .001) and CON (263.1 ± 44.7 vs. 316.1 ± 43.9 K · L^–1; P < .001) sessions, and conversely, a significant decrease in the average neutrophil counts in the EXP (mean difference = –13.7%; P < .001) and CON (mean difference = –13.2%; P < .001) sessions was observed. Lymphocyte counts in the EXP (mean difference = 22.8%; P < .001) and CON (mean difference = 19.3%; P < .001) sessions increased significantly.

Conclusions

There were no significant differences in systemic cellular responses when undergoing aerobic-based exercise with and without a pneumatic tourniquet system.

Level of Evidence

2, prospective comparative study.

Bone Marrow Aspirate Concentrate Is Equivalent to Platelet-Rich Plasma for the Treatment of Knee Osteoarthritis at 2 Years: A Prospective Randomized Trial

BACKGROUND

Autologous platelet-rich plasma (PRP) and bone marrow aspirate concentrate (BMC) are being used clinically as therapeutic agents for the treatment of knee osteoarthritis.

PURPOSE/HYPOTHESIS

The purpose of this study was to compare the efficacy of BMC and PRP on pain and function in patients with knee osteoarthritis up to 24 months after injection. It was hypothesized that patients receiving BMC would have better sustained outcomes than those receiving PRP.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

A total of 90 participants aged between 18 and 80 years with symptomatic knee osteoarthritis (Kellgren-Lawrence grades 1-3) were randomized into 2 study groups: PRP and BMC. Both groups completed the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and subjective International Knee Documentation Committee (IKDC) questionnaire before and 1, 3, 6, 9, 12, 18, and 24 months after a single intra-articular injection of leukocyte-rich PRP or BMC. A linear mixed-effects model was performed to quantify the effects over time and the difference between the groups. This model has the random effect for time to assess the extent in which the change over time differs from one person to another.

RESULTS

An overall 84 patients completed questionnaires from baseline to 12 months; however, 17 patients (n = 9; PRP group) were lost to follow-up at 18 months and 25 (n = 13; PRP group) at 24 months. There were no statistically significant differences in IKDC (P = .909; 95% CI, -6.26 to 7.03) or WOMAC (P = .789; 95% CI, -6.26 to 4.77) scores over time between the groups. Both groups had significantly improved IKDC (P < .001; 95% CI, 0.275-0.596) and WOMAC (P = .001; 95% CI, -0.41 to -0.13) scores from baseline to 24 months after the injection. These improvements plateaued at 3 months and were sustained for 24 months after the injection, with no difference between PRP and BMC at any time point.

CONCLUSIONS

For the treatment of osteoarthritis, PRP and BMC performed similarly out to 24 months. BMC was not superior to PRP.

REGISTRATION

NCT03289416 (ClincalTrials.gov identifier).

Mobilized Peripheral Blood Stem Cells are Pluripotent and Can Be Safely Harvested and Stored for Cartilage Repair

PURPOSE

The primary objective of this study was to reproduce and validate the harvest, processing and storage of peripheral blood stem cells for a subsequent cartilage repair trial, evaluating safety, reliability, and potential to produce viable, sterile stem cells.

METHODS

Ten healthy subjects (aged 19-44 years) received 3 consecutive daily doses of filgrastim followed by an apheresis harvest of mononuclear cells on a fourth day. In a clean room, the apheresis product was prepared for cryopreservation and processed into 4 mL aliquots. Sterility and qualification testing were performed pre-processing and post-processing at multiple time points out to 2 years. Eight samples were shipped internationally to validate cell transport potential. One sample from all participants was cultured to test proliferative potential with colony forming unit (CFU) assay. Five samples, from 5 participants were tested for differentiation potential, including chondrogenic, adipogenic, osteogenic, endoderm, and ectoderm assays.

RESULTS

Fresh aliquots contained an average of 532.9 ± 166. × 10⁶ total viable cells/4 mL vial and 2.1 ± 1.0 × 10⁶ CD34+ cells/4 mL vial. After processing for cryopreservation, the average cell count decreased to 331.3 ± 79. × 10⁶ total viable cells /4 mL vial and 1.5 ± 0.7 × 10⁶ CD34+ cells/4 mL vial CD34+ cells. Preprocessing viability averaged 99% and postprocessing 88%. Viability remained constant after cryopreservation at all subsequent time points. All sterility testing was negative. All samples showed proliferative potential, with average CFU count 301.4 ± 63.9. All samples were pluripotent.

CONCLUSIONS

Peripheral blood stem cells are pluripotent and can be safely harvested/stored with filgrastim, apheresis, clean-room processing, and cryopreservation. These cells can be stored for 2 years and shipped without loss of viability.

CLINICAL RELEVANCE

This method represents an accessible stem cell therapy in development to augment cartilage repair.

Association Between Passive Hip Range of Motion and Pitching Kinematics in High School Baseball Pitchers

BACKGROUND

Limitations in passive hip range of motion (PROM) may negatively affect pitching mechanics in baseball pitchers. Understanding the relationships between PROM and mechanics can assist in the development of injury prevention protocols.

PURPOSE

The purpose of this study was to examine the association of hip rotational PROM with pelvis and trunk rotation during pitching in high school baseball pitchers. Study Design: Cross-sectional.

METHODS

Twenty-five healthy high school baseball pitchers volunteered (15.9 ± 1.1 years; 180.4 ± 5.5 cm; 75.4 ± 9.3 kg). Seated passive hip internal rotation (IR) and external rotation (ER) PROM were measured using a digital inclinometer. Total PROM was calculated (IR+ER). Pitching biomechanical data were collected with a 3-dimensional electromagnetic tracking system while pitchers threw fastballs. Simple linear regressions were performed to examine the association between hip IR, ER, and total PROM with pitching kinematics at foot contact including stride length, pelvis rotation, and trunk rotation.

RESULTS

Only one significant association in PROM and kinematics was observed. Drive leg hip IR PROM was associated with trunk rotation angle [F(1,24) = 4.936, p = 0.036], with an R2 = 0.177. Drive leg total PROM was not associated trunk rotation angle [F(1,24) = 4.144, p = 0.053] with an R2 = 0.153.

CONCLUSIONS

Increased drive leg hip IR PROM was associated with decreased trunk rotation towards home plate. Hip total PROM and ER were not related to pitching mechanics.

LEVEL OF EVIDENCE

2.

Platelet-Rich Plasma: Fundamentals and Clinical Applications

Platelet-rich plasma (PRP) is perhaps the most widely studied of the biologic therapies, with an ever-growing body of evidence supporting its safety and efficacy in decreasing inflammation and pain and promoting healing in the setting of both nonoperative and operative treatments. PRP is produced by the centrifugation of whole blood, isolating its constituent parts based on their unique densities. These density gradients can be selectively harvested so as to obtain different concentrations of various blood product components, such as platelets and leukocytes. A precise and consistent method for describing the essential characteristics of different PRP formulations is critical for both practical and research purposes. The concentration of platelets, method of activation, and the total number of red blood cells (RBCs), white blood cells (WBCs), and neutrophils relative to baseline values are all of particular importance in accurately describing a PRP formulation. The biologic activity of PRP is manifold: platelet α granules promote the release of various growth factors, including vascular endothelial growth factor and tissue growth factor β, while inflammation is modulated through inhibition of the nuclear factor-κB pathway. PRP has been convincingly shown to be efficacious in the setting of patellar tendinopathies, knee osteoarthritis, and lateral epicondylitis. In fact, several recent randomized controlled trials have demonstrated the superiority of PRP over both corticosteroids and hyaluronic acid in treating knee OA-related symptoms. There is also substantial promise for the utility of PRP in treating partial hamstring tears and as an adjunct to rotator cuff (RC) repair, especially in the setting of small- to medium-sized tears, where it appears to exert substantial analgesic effects and promote enhanced rates of RC repair healing.

Biologic Association Annual Summit: 2020 Report

Interest and research in biologic approaches for tissue healing are exponentially growing for a variety of musculoskeletal conditions. The recent hype concerning musculoskeletal biological therapies (including viscosupplementation, platelet-rich plasma, and cellular therapies, or “stem cells”) is driven by several factors, including demand by patients promising regenerative evidence supported by substantial basic and translational work, as well as commercial endeavors that complicate the scientific and lay understanding of biological therapy outcomes. While significant improvements have been made in the field, further basic and preclinical research and well-designed randomized clinical trials are needed to better elucidate the optimal indications, processing techniques, delivery, and outcome assessment. Furthermore, biologic treatments may have potential devastating complications when proper methods or techniques are ignored. For these reasons, an association comprising several scientific societies, named the Biologic Association (BA), was created to foster coordinated efforts and speak with a unified voice, advocating for the responsible use of biologics in the musculoskeletal environment in clinical practice, spearheading the development of standards for treatment and outcomes assessment, and reporting on the safety and efficacy of biologic interventions. This article will introduce the BA and its purpose, provide a summary of the 2020 first annual Biologic Association Summit, and outline the future strategic plan for the BA.

Chondral Lesions of the Knee: An Evidence-Based Approach

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Management of chondral lesions of the knee is challenging and requires assessment of several factors including the size and location of the lesion, limb alignment and rotation, and the physical and mental health of the individual patient.

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There are a multitude of options to address chondral pathologies of the knee that allow individualized treatment for the specific needs and demands of the patient.

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Osteochondral autograft transfer remains a durable and predictable graft option in smaller lesions (<2 cm2) in the young and active patient population.

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Both mid-term and long-term results for large chondral lesions (≥3 cm2) of the knee have demonstrated favorable results with the use of osteochondral allograft or matrix-associated chondrocyte implantation.

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Treatment options for small lesions (<2 cm2) include osteochondral autograft transfer and marrow stimulation and/or microfracture with biologic adjunct, while larger lesions (≥2 cm2) are typically treated with osteochondral allograft transplantation, particulated juvenile articular cartilage, or matrix-associated chondrocyte implantation.

➤

Emerging technologies, such as allograft scaffolds and cryopreserved allograft, are being explored for different graft sources to address complex knee chondral pathology; however, further study is needed.

Platelet-Rich Plasma Devices Can Be Used to Isolate Stem Cells From Synovial Fluid at the Point of Care

PURPOSE

To assess whether point-of-care devices designed for collecting cellular components from blood or bone marrow could be used to isolate viable stem cells from synovial fluid.

METHODS

Male and female patients older than 18 years old with either an acute, anterior cruciate ligament (ACL) injury or knee osteoarthritis (OA) with a minimum estimated 20 mL of knee effusion volunteered. Ten patients with an ACL injury and 10 patients with OA were enrolled. Two milliliters of collected synovial effusion were analyzed and cultured for cellular content. The remaining fluid was combined with whole blood and processed using a buffy-coat based platelet-rich plasma (PRP) processing system. Specimens were analyzed for cell counts, colony-forming unit (CFU) assays, differentiation assays, and flow cytometry.

RESULTS

ACL effusion fluid contained 42.1 ± 20.7 CFU/mL and OA effusion fluid contained 65.4 ± 42.1 CFU/mL. After PRP processing, the counts in ACL-PRP were 101.6 ± 66.1 CFU/mL and 114.8 ± 73.4 CFU/mL in the OA-PRP. Cells showed tri-lineage differentiation potential when cultured under appropriate parameters. When analyzed with flow cytometry, >95% of cells produced with culturing expressed cell surface markers typically expressed by known stem cell populations, specifically CD45-, CD73+, CD29+, CD44+, CD105+, and CD90+.

CONCLUSIONS

Multipotent viable stem cells can be harvested from knee synovial fluid, associated with an ACL injury or OA, and concentrated with a buffy coat-based PRP-processing device.

CLINICAL RELEVANCE

PRP devices can be used to harvest stem cells from effusion fluids. Methods to use effusion fluid associated with an ACL injury and OA should be investigated further.

Elevation of Peripheral Blood CD34+ and Platelet Levels After Exercise With Cooling and Compression

Purpose

To analyze the cellular response and chemokine profiles following exercise using cooling and blood flow restriction on the Vasper system.

Methods

Healthy male patients between the ages of 20 and 39 years were recruited. Testing was performed on the Vasper system, a NuStep cross-trainer with concomitant 4-limb venous compression with proximal arm cuffs at 40 mm Hg and proximal leg cuffs at 65 mm Hg. A cooling vest and cooling mat (8.3°C) were used. A 7-minute warm-up followed by alternating 30- and 60-second sprints with 1.5 and 2 minutes of active recovery, respectively, between each sprint. Peripheral blood was drawn before exercise, immediately following exercise (T20), 10 minutes after the first post-exercise blood draw (T30), and then every 30 minutes (T60, T90, T120, T150, T180). A blood draw occurred at 24 hours’ postexercise. Complete blood count, monoclonal flow cytometry for CD34+, and enzyme-linked immunosorbent assay were used to analyze the samples.

Results

Sixteen healthy male patients (29.5 ± 4.5years, 1.78 ± 0.05m, 83.7 ± 11.4 kg) were enrolled. There was an immediate, temporary increase in white blood cell counts, marked by an increase in lymphocyte differential (38.3 ± 6.5 to 44.3 ± 9.0%, P = .001), decrease in neutrophil differential (47.8 ± 6.6 to 42.0 ± 9.1%, P < .001), and platelets (239.5 ± 57.2 to 268.6 ± 86.3 K⋅μL^–1, P = .01). Monocytes significantly decreased from PRE to T90 (9.8 ± 1.1 to 8.9 ± 1.1K/μL, P < .001) and T120 (8.9 ± 1.1 K/μL, P < .0001). There was a significant increase in CD34+ cells (3.9 ± 2.0 to 5.3 ± 2.8 cells⋅μL^–1, P < .001). No detectable differences in measured cytokine levels of interleukin (IL)-10, IL-6, granulocyte-macrophage colony-stimulating factor , IL-1ra, tumor necrosis factor-α, or IL-2 were observed.

Conclusions

A significant elevation of peripheral blood CD34+ and platelet levels immediately following the exercise session was observed; however, there was no effect on peripheral circulation of IL-10, IL-6, IL-1ra, tumor necrosis factor-α, or IL-2.

Clinical Relevance

Exercise can be considered as a way to manipulate point-of-care blood products like platelet-rich plasma and may increase product yield.

Blood Flow Restriction Training Using the Delfi System Is Associated With a Cellular Systemic Response

Purpose

To determine the effects of blood flow restriction (BFR) exercise on CD34⁺ cells, platelets, white blood cells, neutrophils, lymphocytes, lactate, and glucose.

Methods

Healthy participants aged 20 to 39 years who were able to perform the exercise sessions were recruited. Participants underwent an experimental (EXP) occluded testing session and a control (CON) session using the Delfi Personalized Tourniquet System. Blood draws were performed prior to testing and immediately after the exercise session. Blood analysis consisted of a complete blood count as well as flow cytometry to measure peripheral CD34⁺ counts as a marker for hematopoietic progenitor cells.

Results

Fourteen men (aged 30.8 ± 3.9 years) volunteered. There was a significant increase in average CD34⁺ counts immediately after the EXP session only (3.1 ± 1.2 cells ⋅ μL^-1 vs 5.2 ± 2.9 cells ⋅ μL^-1, P = .012). Platelet counts were significantly elevated after both sessions, with the average increase being higher after the EXP session (mean difference [MD], 34,200/μL; P < .002) than after the CON session (MD, 11,600/μL; P < .002). White blood cell counts significantly increased after both the EXP (8,400 ± 2,200/μL vs 6,300 ± 1,600/μL; P < .001) and CON (MD, 900/μL; P < .001) sessions. There was a significant increase from baseline to immediately after exercise in the average number of lymphocytes (MD, 6.3%; P < .001) and, conversely, a significant decrease in the average neutrophil count (MD, 6.5%; P < .001) in the EXP session only. Lactate levels significantly increased in the EXP (MD, 6.1 mmol ⋅ L^-1; P = .001) and CON (MD, 3.6 mmol ⋅ L^-1; P = .001) groups. No changes in glucose levels were observed.

Conclusions

Exercise with BFR causes a significant post-exercise increase in peripheral hematopoietic progenitor cells and platelets, beyond that of standard resistance training.

Clinical Relevance

BFR can be considered a way to manipulate point-of-care blood products such as platelet-rich plasma to increase product yield.

Lower Extremity Pain and Pitching Kinematics and Kinetics in Collegiate Softball Pitchers

The primary aims of the study were (1) to examine kinematics and kinetics of those pitching with and without lower extremity pain in collegiate softball pitchers, and (2) to determine if there was an association between the lower extremity pain and lower extremity kinematics, trunk kinematics, and shoulder kinetics in collegiate softball pitchers. Thirty-seven NCAA Division I female collegiate softball pitchers (19.8±1.3 yrs,173.7±7.7 cm, 79.0±12.4 kg) participated. Participants were divided into two groups, those who were currently experiencing lower extremity pain and those who were not. Participants threw three rise ball pitches. Kinematic data were collected at 100 Hz using an electromagnetic tracking system. Mann-Whitney U tests revealed no significant kinematic or kinetic differences between pitchers with and without lower extremity pain. Additionally, there were no significant correlations between pain and recorded kinematic and kinetic variables. Considering there were no biomechanical differences observed between pitchers, coaches and athletic trainers should take caution with athlete assessment since athletes may not display altered biomechanics. Further examination into the duration and degree of pain is needed in an attempt to fully understand the implication of pain and pitching mechanics.

Autologous thrombin preparations: Biocompatibility and growth factor release

Platelet-rich plasma (PRP) has been investigated to promote wound healing in a variety of tissues. Thrombin, another essential component of wound healing, is sometimes combined with PRP to generate a fibrin clot in order to retain the sample at the delivery site and to stimulate growth factor release. Using a fully autologous approach, autologous serum (AS) with thrombin activity can be prepared using a one-step procedure by supplementing with ethanol (E⁺ AS) to prolong room temperature stability or prepared ethanol free (E^- AS) by utilizing a two-step procedure to prolong stability. The objective of this study was to evaluate potential wound healing mechanisms of these two preparations using commercially available devices. A variety of tests were conducted to assess biocompatibility and growth factor release from PRP at various ratios. It was found that E^- AS contained greater leukocyte viability in the product (97.1 ± 2.0% compared to 41.8 ± 11.5%), supported greater bone marrow mesenchymal stem cell proliferation (3.7× vs 0.8× at a 1:4 ratio and 3.6× vs 1.6× at a 1:10 ratio), and stimulated release of growth factors and cytokines from PRP to a greater extent than E⁺ AS. Of the 36 growth factors and cytokines evaluated, release of 27 of them were significantly reduced by the presence of ethanol in at least one of the tested configurations. It is concluded that the high concentrations of ethanol needed to stabilize point of care autologous thrombin preparations could be detrimental to normal wound healing processes.

Editorial Commentary: Food and Drug Administration Regulation of Biologics in Orthopaedics: Am I the Only One Around Here Who Gives a Flip About the Rules?!?!

As orthobiologics have appeared and stayed a part of our clinical practices, at times it seems that we (orthopaedic surgeons) have not focused appropriate attention and/or interest on regulation. However, regulation has focused on us, as the Food and Drug Administration (FDA) has made it clear. Safety and efficacy are top priorities of the FDA and should be ours too. The FDA has transmitted their communications to industry and to clinicians; we are responsible for understanding their regulations and the FDA definitions of relevant terms, including "minimal manipulation" and "homologous" use. Finally, FDA "clearance" does not mean safe or efficacious, nor compliant with other federal regulations.

Biceps Tendon Changes and Pitching Mechanics in Youth Softball Pitchers

With the lack of pitch count regulation, youth softball pitchers are experiencing unremitting high stresses on the anterior shoulder. The purpose of this study was to examine the association of acute changes in the long head of the biceps tendon with pitching kinematics and kinetics in youth softball pitchers following an acute bout of pitching. Twenty-three softball pitchers (12.17±1.50 yrs.; 160.32±9.41 cm; 60.40±15.97 kg) participated. To investigate the association between biceps tendon changes and kinematic and kinetic changes from pre- to post-simulated game, each biceps tendon measure was split into those whose biceps tendon thickness, width, and/or area increased pre- to post-simulated game, and those whose did not. There were significant differences in biceps tendon longitudinal thickness (Z=- 2.739, p=0.006) and pitch speed; as well as a difference between groups in biceps tendon transverse thickness and the amount of change in trunk rotation at the start of the pitching motion (p=0.017) and the amount of change in trunk flexion at ball release (p=0.030). This study illustrates the association of trunk and lower extremity kinematics and shoulder kinetics with morphologic changes in the biceps tendon with an acute bout of windmill softball pitching.

3-T MRI mapping is a valid in vivo method of quantitatively evaluating the anterior cruciate ligament: rater reliability and comparison across age

OBJECTIVE

As biologic augmentation methods emerge, objective measures of soft tissues are necessary for developmental study. The purpose of this study was to develop a quantitative MRI mapping protocol for the ACL. The objectives were (1) to provide age-based T2 relaxation, T2* relaxation, and volume values in healthy individuals, (2) to establish the intra-rater and inter-rater reliability of ACL mapping, and (3) to determine whether 3-T or 7-T MRI is more appropriate for future clinical trials.

MATERIALS AND METHODS

Thirty healthy participants, aged 18-62, asymptomatic for knee pathology and without history of knee injury underwent both a 3-T and 7-T MRI. Manual image mapping of the anterior cruciate ligament was performed by two observers and processed to obtain T2, T2*, and volume values. Analysis of variance and two-way random effects model were used to calculate statistical significance and intraclass correlation coefficients.

RESULTS

Across all participants, 3-T and 7-T mean T2, T2* and volume values were 37.1 ± 7.9 and 39.7 ± 6.2 ms (p = 0.124), 10.9 ± 1.3 and 10.9 ± 0.9 ms (p = 0.981), and 2380 ± 602 and 2484 ± 736 mm³ (p = 0.551), respectively. The T2, T2*, and volume did not vary between age cohorts (p > 0.05). Excellent inter-rater and intra-rater reliability regarding T2 and T2* values was found. While ACL volume exhibited good inter-rater reliability and excellent intra-rater reliability.

CONCLUSIONS

T2 relaxation values and ACL volume do not vary with age and therefore can be used as a quantifiable, non-invasive method to assess ACL graft maturation. 7-T MRI analysis was not superior to 3-T MRI analysis, suggesting that 3-T MRI is practical and capable for future comparative studies.

Bone Marrow Aspirate Concentrate Is Equivalent to Platelet-Rich Plasma for the Treatment of Knee Osteoarthritis at 1 Year: A Prospective, Randomized Trial

Background:

Approximately 47 million people in the United States have been diagnosed with arthritis. Autologous platelet-rich plasma (PRP) injections have been documented to alleviate symptoms related to knee osteoarthritis (OA) in randomized controlled trials, systematic reviews, and meta-analyses. Autologous bone marrow aspirate concentrate (BMC) injections have also emerged as a treatment option for knee OA, with a limited clinical evidence base.

Purpose:

To compare the efficacy of BMC to PRP for the treatment of knee OA regarding pain and function at multiple time points up to 12 months after an injection. We hypothesized that BMC will be more effective in improving outcomes in patients with knee OA.

Study Design:

Randomized controlled trial; Level of evidence, 2

Methods:

A total of 90 participants aged between 18 and 80 years with symptomatic knee OA (Kellgren-Lawrence grades 1-3) were randomized into 2 study groups: PRP and BMC. Both groups completed the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and subjective International Knee Documentation Committee (IKDC) questionnaires before and 1, 3, 6, 9, and 12 months after a single intra-articular injection of leukocyte-rich PRP or BMC.

Results:

There were no statistically significant differences in baseline IKDC or WOMAC scores between the 2 groups. All IKDC and WOMAC scores for both the PRP and BMC groups significantly improved from baseline to 1 month after the injection (P < .001). These improvements were sustained for 12 months after the injection, with no difference between PRP and BMC at any time point.

Conclusion:

Both PRP and BMC were effective in improving patient-reported outcomes in patients with mild to moderate knee OA for at least 12 months; neither treatment provided a superior clinical benefit. Autologous PRP and BMC showed promising clinical potential as therapeutic agents for the treatment of OA, and while PRP has strong clinical evidence to support its efficacy, BMC has limited support. This study did not prove BMC to be superior to PRP, providing guidance to clinicians treating OA. It is possible that the results were affected by patients knowing that there was no control group.

Registration:

NCT03289416 (ClinicalTrials.gov identifier).

Effects of a Simulated Game on Pitching Kinematics in Youth Softball Pitcher

Despite evidence that overuse is the most common mechanism of injury, softball pitchers currently have no pitch count regulations. Pain has been associated with certain pitching pathomechanics, and some reports indicate increased pain following a single pitching bout. Therefore, the purpose of this study was to examine trunk and lower extremity kinematics during the first and last inning of a game, as well as last inning pitch volume in youth softball pitchers. Thirty-two youth softball pitchers (12.4±1.6 years, 159.4±8.9 cm, 62.0±13.6 kg) pitched a simulated game. Three fastballs were averaged and analyzed from the first and last inning. Kinematic data were collected at 100Hz using an electromagnetic system, synced with motion analysis software. A Wilcoxon signed rank test revealed pitchers exhibited less trunk rotation toward their pitching arm side in the last inning. A bivariate Pearson's correlation showed volume of pitches was correlated with stride length (r=0.367, p=0.039) and center of mass (r=0.364, p=0.041) at the start of the pitch, and trunk flexion at top of pitch (r=-0.392, p=0.026), foot contact (r=-0.413, p=0.019), and follow-through (r=-0.436, p=0.013). This study found that pitching a simulated game did result in altered pitching mechanics, meanwhile pitch volume was also correlated with pitching mechanics.

Epidemiology of Shoulder and Elbow Injuries Among US High School Softball Players, 2005-2006 Through 2016-2017

Background:

Injury prevalence has been well described among baseball athletes; similarly, a better understanding of injuries in softball athletes is needed.

Purpose:

To examine shoulder and elbow injury epidemiology among high school softball athletes in the United States.

Study Design:

Descriptive epidemiological study.

Methods:

Injury data were obtained from the National High School Sports-Related Injury Surveillance System, which captures data from a large national sample of US high schools. Annually, a random sample of 100 high schools provided a representative sample with respect to the 4 US Census geographic regions and 2 school sizes (cutoff point, 1000 students). Athletic trainers from participating schools reported data for athlete-exposures (AEs; practice or competition) and shoulder and elbow injuries from 2005-2006 through 2016-2017.

Results:

A total of 239 shoulder injuries and 85 elbow injuries occurred within 2,095,329 AEs. The overall shoulder injury rate was 1.14 per 10,000 AEs, whereas the overall elbow injury rate was 0.41 per 10,000 AEs. Injuries to the shoulder were more likely to occur during competition as compared with practice (rate ratio, 1.28; 95% CI, 0.99-1.65). Half of the shoulder (50.4%) and elbow 48.9% injuries were due to an overuse/chronic mechanism. Of the athletes sustaining an injury, 86.8% with shoulder injuries and 93.0% with elbow injuries returned to play within 21 days. Only 16.7% of shoulder injuries and 17.5% of elbow injuries were sustained by pitchers.

Conclusion:

Shoulder and elbow injury rates, time to return, and percentage of injuries among pitchers were far lower in high school softball than previously reported values for high school baseball. There were relatively low incidences of shoulder and elbow injuries in high school softball as compared with baseball, with few injuries requiring lengthy time to return to play.

The Influence of an Active Glove Arm in Softball Pitching: A Biomechanical Evaluation

The purpose of this study was to determine whether glove arm kinematics during a windmill softball pitch impact pelvic and trunk kinematics as well as pitching arm shoulder kinetics. Thirty-Nine college softball pitchers (20.0±1.4 yrs.; 174.7±6.1 cm; 82.0±13.0 kg; 10.7±2.7 yrs. of experience) threw 3 pitches to a catcher while kinematic and kinetic data were collected. Pearson product moment correlations were run, and significant correlations found with glove arm kinematics, occurring before pelvis kinematics, trunk kinematics, and shoulder kinetics, were then put through a linear regression to identify whether there was any potential cause and effect. Results revealed that glove arm elbow flexion during phase 1 significantly predicted normalized shoulder rotation moment during phase 4 (t=2.60, p=0.013). Additionally, glove arm shoulder horizontal abduction during phase 1 significantly predicted normalized shoulder moment in phase 3 (t=- 2.40, p=0.021) and pelvic angular velocity during phase 3 (t=-  3.20, p=0.003). In conclusion, an active glove arm was predictive of a more efficient kinetic chain later in the windmill pitching motion and could possibly play a role in preventing injury by lessening pitching shoulder joint loads.

Exercise-Mobilized Platelet-Rich Plasma: Short-Term Exercise Increases Stem Cell and Platelet Concentrations in Platelet-Rich Plasma

PURPOSE

To evaluate the effects of vigorous short-term exercise on the platelet and other cellular components of 2 point-of-care blood-processing devices: a buffy coat-based platelet-rich plasma (PRP) product and a plasma-based PRP product.

METHODS

Twenty healthy subjects (aged 21-45 years) participated in a 20-minute vigorous exercise regimen on an upright stationary bike at 70% to 85% of maximum target heart rate. Pre- and post-exercise blood was processed in either a plasma-based or automated buffy coat-based PRP system. Complete blood counts were used to compare the cellular components in whole blood and the PRP products.

RESULTS

Exercise significantly increased the concentrations of platelets by over 20% in whole blood (P < .001) and in both PRP products (P = .002 and P = .018). Both devices performed consistently with pre- and post-exercise blood. Buffy coat-based PRP prepared after exercise was also significantly larger in volume and had a significantly higher concentration of mobilized hematopoietic stem cells (hematopoietic progenitor cells [HPCs], from 1.7/μL to 2.7/μL, P = .043). The concentrations of all white blood cell types were increased, which could be differentially collected in the devices studied.

CONCLUSIONS

Exercise can be used to consistently alter the composition of PRP. Twenty minutes of vigorous exercise can increase platelet concentrations in plasma-based and buffy coat-based PRP products and can increase HPC concentrations and volume in buffy coat-based PRP.

CLINICAL RELEVANCE

This study shows a nonpharmacologic method to increase platelet and HPC harvests from peripheral blood. This is important because it highlights a method for altering biological therapies with limited comorbidity.

Upper Extremity Pain and Pitching Mechanics in National Collegiate Athletic Association (NCAA) Division I Softball

The purpose of this study was to evaluate pitching mechanics between female softball pitchers with upper extremity pain and those without upper extremity pain. Specifically, the trunk, shoulder and elbow kinematics and shoulder kinetics during the change-up softball pitch were examined. Fifty-five collegiate softball pitchers participated, divided into those with upper extremity pain (20.0±1.3 yrs.; 174.4±6.9 cm; 82.9±12.4 kg; 11.1±2.6 yrs. of experience; n=23) and those who were pain-free (19.9±1.4 yrs.; 173.8±6.9 cm; 81.4±12.5 kg; 10.0±2.5 yrs. of experience; n=32). Pitching mechanics were obtained via the trakSTAR^™ electromagnetic tracking system (Ascension Technologies, Inc., Burlington, VT, USA). Mann-Whitney U tests revealed significant differences in shoulder horizontal abduction at foot contact (p=0.014, U=153, Z=2.450) and trunk lateral flexion at ball release (p=0.012, U=150, Z=-2.515); and between shoulder distraction force at ball release (p=0.034, U=168, Z=-2.124). The pain group illustrated greater shoulder horizontal abduction at foot contact, less trunk lateral flexion towards the throwing side at ball release, and greater shoulder distraction at ball release than the pain-free group. The differences in trunk and shoulder kinematics, and shoulder kinetics between groups allows for insight into further studies examining injury pervasiveness in softball pitching.

Relationship of Glove Arm Kinematics With Established Pitching Kinematic and Kinetic Variables Among Youth Baseball Pitchers

Background:

While the kinematics of the pitching arm, trunk, and pelvis have been described and studied, glove arm kinematics remain an understudied portion of the pitching motion. Baseball pitchers seek to achieve maximum ball velocity in a fashion that does not place the arm at risk of injury.

Purpose:

To assess the relationship between glove arm shoulder horizontal abduction and elbow flexion and pitching arm kinematics and kinetics among youth pitchers to determine whether recommendations can be made toward a safer pitching motion.

Study Design:

Descriptive laboratory study.

Methods:

Thirty-three right-handed youth male baseball pitchers (mean ± SD: age, 13.6 ± 2.0 years; height, 169.4 ± 14.3 cm; weight, 63.5 ± 13.0 kg; experience, 7.3 ± 3.0 years) threw 3 fastballs to a catcher while kinematic data were collected with an electromagnetic tracking system. The Spearman rank-order test was used to identify relationships between glove arm horizontal abduction and glove arm elbow flexion and various kinematics and kinetics found at maximum shoulder external rotation (MER) and ball release for the fastest fastball delivered by each participant.

Results:

At MER, there were significant relationships found between a more flexed glove arm elbow and increased pitching arm elbow valgus force (r_s[31] = –0.52, P = .002), increased pitching arm shoulder anterior force (r_s = –0.39, P = .024), and decreased hip velocity (r_s[31] = –0.45, P = .009). Additionally, there were significant relationships between greater glove arm horizontal abduction at MER and increased pitching arm humeral velocity (r_s[31] = 0.52, P = .002) and increased trunk rotational velocity (r_s[31] = 0.40, P = .022) at MER.

Conclusion:

A more extended glove arm elbow and more horizontally abducted glove arm shoulder at MER could prove to be more advantageous for performance and possibly be a safer motion for the baseball thrower.

Clinical Relevance:

The orthopaedic community can dictate safer biomechanics when communicating with pitchers, trainers, and pitching coaches.

A Biomechanical Assessment of Biceps Femoris Repair Techniques

Background:

Knee injuries encountered in clinical practice can involve avulsions of the biceps femoris from the fibula and proximal tibia. Advances in tendon repair methods now allow for repairs with increased surface areas using modern suture anchor techniques. Despite descriptions of repair techniques, there are no biomechanical studies on the biceps femoris for comparison.

Purpose/Hypothesis:

The objective of this controlled laboratory study was to determine the failure load of the native biceps femoris distal insertion and to evaluate modern repair techniques. Our hypothesis was 2-fold: (1) Suture repairs to the tibia and fibula would perform better on tensile testing than repairs to the fibula alone, and (2) complex bridge repairs, similar to those frequently used in rotator cuff surgery, would perform better on tensile testing than simple repairs.

Study Design:

Controlled laboratory study.

Methods:

A total of 40 paired, fresh-frozen cadaveric specimens were dissected, identifying the biceps femoris and its insertion on the proximal tibia and fibula. The native biceps femoris footprint was left intact in 8 specimens and tested to failure on a uniaxial materials testing machine evaluating tensile properties, while in the other 32 specimens, the biceps femoris insertion was dissected using a No. 15 scalpel blade, underwent repair, and was then tested to failure on a uniaxial materials testing machine evaluating tensile properties. Four repair constructs were evaluated, with 8 specimens allocated for each: construct 1 involved a simple repair (ie, passing suture through tissue in a running Krackow fashion and tying at the anchor site) to the fibula with 2 suture anchors, construct 2 involved a simple repair to the fibula and tibia with 3 suture anchors, construct 3 was a fibular repair with a tibial suture bridge involving the fibula and tibia and 3 suture anchors, construct 4 involved a transosseous repair through the fibula and 1 suture anchor on the tibia. Analysis of variance was used to evaluate for significance of the mean failure load and stiffness between groups.

Results:

The mean (±95% CI) failure loads were the following: native biceps femoris, 1280 ± 247.0 N; simple fibular repair, 173 ± 84.6 N; simple fibular and tibial repair, 176 ± 48.1 N; fibular repair with tibial suture bridge, 191 ± 78.5 N; and transosseous repair, 327 ± 66.3 N. The mean stiffness values were the following: native, 46 ± 13.0 N/mm; simple fibular repair, 16 ± 5.1 N/mm; simple fibular and tibial repair, 14 ± 5.4 N/mm; fibular repair with tibial suture bridge, 13 ± 2.8 N/mm; and transosseous repair, 15 ± 2.5 N/mm. Interconstruct comparison of failure loads revealed no statistical difference between constructs utilizing anchors alone. The transosseous repair showed a significant difference for the failure load when compared with each anchor repair construct (P = .02, .02, and .04 for constructs 1, 2, and 3, respectively). Interconstruct comparison of stiffness revealed no statistical difference between all constructs (P > .86). None of the repair techniques re-created the failure load or stiffness of the native biceps femoris tendon (P = .02).

Conclusion:

In this biomechanical study, no difference was found between the mean failure loads of different biceps femoris repair constructs involving suture anchors alone and No. 2 braided polyester and ultra–high-molecular-weight polyethylene suture. A technique involving transosseous fibular tunnels and 2-mm suture tape illustrated a greater mean failure load than repairs relying on suture anchors for fixation.

Clinical Relevance:

Understanding the tensile performance of biceps femoris repair constructs aids clinicians with preoperative and intraoperative decisions. Current biceps femoris repair techniques do not approximate the native strength of the tendon. A transosseous style of repair offers the highest failure load.

Viable Stem Cells Are in the Injury Effusion Fluid and Arthroscopic Byproducts From Knee Cruciate Ligament Surgery: An In Vivo Analysis

PURPOSE

To examine the number of viable stem cells contained in the postinjury effusion fluid and the waste byproducts of arthroscopic cruciate ligament surgery.

METHODS

This study included patients older than 18 years of age with acute (<5 weeks old) cruciate ligament injuries requiring arthroscopic surgery. The postinjury effusion fluid (effusion fluid), fat pad and cruciate ligament stump debridement tissue (byproduct tissue), and arthroscopic fluid collected during fat pad and/or stump debridement (byproduct fluid) were collected at the time of surgery from 30 individuals. Specimens were analyzed, investigating cell viability, nucleated cell counts, cell concentrations, colony-forming unit assays, and flow cytometry. Samples from the first 20 individuals were collected in small specimen containers, and samples from the last 10 individuals were collected in larger specimen containers.

RESULTS

Cells of the injury effusion exhibited the greatest viability (86.4 ± 1.31%) when compared with the small volume harvest byproduct tissue (50.2 ± 2.5%, P = .0001), small volume harvest byproduct fluid (48.8 ± 1.88%, P = .0001), large volume harvest byproduct tissue (70.1 ± 5.6%, P = .0001), and large volume harvest byproduct fluid (60.3 ± 3.41%, P = .0001). The culture analysis of fibroblast colony-forming units found on average 1916 ± 281 progenitor cells in the effusion fluid, 2488 ± 778 progenitor cells in the byproduct tissue, and 2357 ± 339 progenitor cells in the byproduct fluid. Flow cytometry confirmed the presence of immature cells and the presence of cells with markers typically expressed by known stem cell populations.

CONCLUSIONS

Viable stem cells are mobilized to the postinjury effusion at the time of cruciate ligament injury and can be found in the byproduct waste of cruciate ligament surgery.

CLINICAL RELEVANCE

The methodology around effusion fluid and byproduct tissue capture during cruciate ligament surgery should be investigated further. Cell amounts available from these tissues with current technologies are not sufficient for immediate evidence-based clinical application.

Biomechanical Comparison of Parallel and Crossed Suture Repair for Longitudinal Meniscus Tears

Background:

Longitudinal meniscus tears are commonly encountered in clinical practice. Meniscus repair devices have been previously tested and presented; however, prior studies have not evaluated repair construct designs head to head. This study compared a new-generation meniscus repair device, SpeedCinch, with a similar established device, Fast-Fix 360, and a parallel repair construct to a crossed construct. Both devices utilize self-adjusting No. 2-0 ultra–high molecular weight polyethylene (UHMWPE) and 2 polyether ether ketone (PEEK) anchors.

Hypothesis:

Crossed suture repair constructs have higher failure loads and stiffness compared with simple parallel constructs. The newer repair device would exhibit similar performance to an established device.

Study Design:

Controlled laboratory study.

Methods:

Sutures were placed in an open fashion into the body and posterior horn regions of the medial and lateral menisci in 16 cadaveric knees. Evaluation of 2 repair devices and 2 repair constructs created 4 groups: 2 parallel vertical sutures created with the Fast-Fix 360 (2PFF), 2 crossed vertical sutures created with the Fast-Fix 360 (2XFF), 2 parallel vertical sutures created with the SpeedCinch (2PSC), and 2 crossed vertical sutures created with the SpeedCinch (2XSC). After open placement of the repair construct, each meniscus was explanted and tested to failure on a uniaxial material testing machine. All data were checked for normality of distribution, and 1-way analysis of variance by ranks was chosen to evaluate for statistical significance of maximum failure load and stiffness between groups. Statistical significance was defined as P < .05.

Results:

The mean maximum failure loads ± 95% CI (range) were 89.6 ± 16.3 N (125.7-47.8 N) (2PFF), 72.1 ± 11.7 N (103.4-47.6 N) (2XFF), 71.9 ± 15.5 N (109.4-41.3 N) (2PSC), and 79.5 ± 25.4 N (119.1-30.9 N) (2XSC). Interconstruct comparison revealed no statistical difference between all 4 constructs regarding maximum failure loads (P = .49). Stiffness values were also similar, with no statistical difference on comparison (P = .28).

Conclusion:

Both devices in the current study had similar failure load and stiffness when 2 vertical or 2 crossed sutures were tested in cadaveric human menisci.

Clinical Relevance:

Simple parallel vertical sutures perform similarly to crossed suture patterns at the time of implantation.

Regenerative treatments to enhance orthopedic surgical outcome

In orthopedic surgery there has been a never-ending quest to improve surgical outcome and the patient's experience. Progression has been marked by the refinement of surgical techniques and instruments and later by enhanced diagnostic imaging capability, specifically magnetic resonance. Over time implant optimization was achieved, along with the development of innovative minimally invasive arthroscopic technical skills to leverage new versions of classic procedures and implants to improve short-term patient morbidity and initial, mid-term, and long-term patient outcomes. The use of regenerative and/or biological adjuncts to aid the healing process has followed in the drive for continual improvement, and major breakthroughs in basic science have significantly unraveled the mechanisms of key healing and regenerative pathways. A wide spectrum of primary and complementary regenerative treatments is becoming increasingly available, including blood-derived preparations, growth factors, bone marrow preparations, and stem cells. This is a new era in the application of biologically active material, and it is transforming clinical practice by providing effective supportive treatments either at the time of the index procedure or during the postoperative period. Regenerative treatments are currently in active use to enhance many areas of orthopedic surgery in an attempt to improve success and outcome. In this review we provide a comprehensive overview of the peer-reviewed evidence-based literature, highlighting the clinical outcomes in humans both with preclinical data and human clinical trials involving regenerative preparations within the areas of rotator cuff, meniscus, ligament, and articular cartilage surgical repair.

Distal Insertions of the Biceps Femoris: A Quantitative Analysis

Background:

Avulsion of the biceps femoris from the fibula and proximal tibia is encountered in clinical practice. While the anatomy of the primary posterolateral corner structures has been qualitatively and quantitatively described, a quantitative analysis regarding the insertions of the biceps femoris on the fibula and proximal tibia is lacking.

Purpose:

To quantitatively assess the insertions of the biceps femoris, fibular collateral ligament (FCL), and anterolateral ligament (ALL) on the fibula and proximal tibia as well as establish relationships among these structures and to pertinent surgical anatomy.

Study Design:

Descriptive laboratory study.

Methods:

Dissections were performed on 12 nonpaired, fresh-frozen cadaveric specimens identifying the biceps femoris, FCL, and ALL, and their insertions on the proximal tibia and fibula. The footprint areas, orientations, and distances from relevant osseous landmarks were measured using a 3-dimensional coordinate measurement device.

Results:

Dissection produced 6 easily identifiable and reproducible anatomic footprints. Tibial footprints included the insertion of the ALL and an insertion of the biceps femoris (TBF). Fibular footprints included the insertion of the FCL, a distal insertion of the biceps femoris (DBF), a medial footprint of the biceps femoris (MBF), and a proximal footprint of the biceps femoris (PBF). The mean area of these footprints (95% CI) was as follows: ALL, 53.0 mm² (38.4-67.6); TBF, 93.9 mm² (72.0-115.8); FCL, 86.8 mm² (72.3-101.2); DBF, 119 mm² (91.1-146.9); MBF, 46.8 mm² (29.0-64.5); and PBF, 215 mm² (192.4-237.5). The mean distance (95% CI) from the Gerdy tubercle to the center of the ALL footprint was 24.3 mm (21.6-27.0) and to the center of the TBF was 22.5 mm (21.0-24.0). The center of the DBF was 8.68 mm (7.0-10.3) from the anterior border of the fibula, the center of the FCL was 14.6 mm (12.5-16.7) from the anterior border of the fibula and 20.7 mm (19.0-22.4) from the tip of the fibular styloid, and the center of the PBF was 8.96 mm (8.2-9.7) from the tip of the fibular styloid.

Conclusion:

A tibial footprint, distal fibular footprint, medial fibular footprint, and proximal fibular footprint were all consistent components of the insertion of the biceps femoris. Consistent relationships existed between the biceps femoris and insertions of the ALL and FCL.

Clinical Relevance:

The size of these footprints and distances from pertinent surgical landmarks will guide repairs of biceps femoris avulsion injuries.

Biomechanical comparison of arthroscopic repair constructs for radial tears of the meniscus

BACKGROUND

Radial tears of the meniscus represent a challenging clinical scenario because benign neglect and partial meniscectomy have both been shown to have negative biomechanical and long-term clinical consequences.

HYPOTHESIS

Complex suture repair constructs have higher failure loads and stiffness values compared with simple constructs.

STUDY DESIGN

Controlled laboratory study.

METHODS

After radial transection of human cadaveric menisci, simulated tears were repaired arthroscopically by use of 1 of 4 repair constructs: (1) 2 inside-out horizontal sutures, (2) 2 all-inside horizontal sutures, (3) an all-inside Mason-Allen construct consisting of 4 sutures, or (4) an all-inside construct consisting of a figure-of-8 suture plus 1 horizontal suture. Meniscus specimens were harvested and tested to failure on an Instron machine. The Kruskal-Wallis test was used to evaluate for significance of maximal failure load and stiffness between groups.

RESULTS

The mean maximum failure loads were 64 ± 20 N (inside-out horizontal construct), 75 ± 16 N (all-inside horizontal construct), 86 ± 19 N (Mason-Allen construct), and 113 ± 22 N (figure-of-8 plus horizontal construct). Interconstruct comparison revealed a statistically significant difference between the figure-of-8 plus horizontal construct and all 3 remaining constructs (P < .02) as well as the Mason-Allen construct when compared with the inside-out horizontal construct (P < .01). Statistical significance was not found between the all-inside horizontal construct and the Mason-Allen construct or between the all-inside horizontal construct and the inside-out horizontal construct (P = .2 and .7, respectively). Stiffness values were lower for the inside-out construct compared with the all-inside constructs (P < .05).

CONCLUSION

Complex all-inside repair constructs had significantly higher failure loads than a conventional, simple inside-out suture repair construct for repair of radial meniscal tears. Stiffness values among the all-inside groups were greater than those for the inside-out group.

CLINICAL RELEVANCE

Arthroscopic techniques are presented to produce stronger radial meniscal tear repairs.

Biomechanical comparison of arthroscopic repair constructs for meniscal root tears

BACKGROUND

Complete meniscal root tears render the meniscus nonfunctional. Repair constructs have been presented and tested; however, prior studies have evaluated suture patterns placed ex vivo without simulating an in vivo surgical setting. This study introduces a new double-locking loop suture pattern and compares its biomechanical properties and execution time with commonly used suture patterns. All constructs were performed using an all-inside arthroscopic technique.

HYPOTHESIS

Complex suture repair constructs have higher failure loads, stiffness, and execution times compared with simple constructs.

STUDY DESIGN

Controlled laboratory study.

METHODS

Sutures were placed arthroscopically into the posterior horn root region of the medial and lateral menisci in 21 cadaveric knees. Four repair constructs were evaluated: 2 simple sutures (2SS), 1 inverted mattress suture (1MS), 1 double-locking loop suture (1DLS), and 2 double-locking loop sutures (2DLS). In total, 40 posterior meniscal roots were tested, with 10 trials for each construct. After arthroscopic placement of the root repair constructs, each meniscus was explanted and tested to failure on a uniaxial materials testing machine. The Kruskal-Wallis test was used to evaluate for the significance of maximum failure loads and stiffness between groups.

RESULTS

The mean maximum failure loads were 137 ± 49 N (2SS), 126 ± 44 N (1MS), 186 ± 43 N (1DLS), and 368 ± 76 N (2DLS). Interconstruct comparison revealed a statistical difference between 2DLS and all 3 remaining constructs (P < .01) and 1DLS when compared with 2SS and 1MS (P < .01 for both). Statistical significance was not found between 2SS and 1MS (P = .8). The mean times for repair of the 4 fixation techniques were 1.8 ± 0.9 minutes (2SS), 2.4 ± 1.9 minutes (1MS), 4.7 ± 2.0 minutes (1DLS), and 5.4 ± 0.6 minutes (2DLS).

CONCLUSION

The double-locking loop suture repair technique had significantly higher failure loads compared with the 3 other methods tested. As the complexity of repair constructs increases, failure loads and surgical times increase.

CLINICAL RELEVANCE

Complex suture patterns can be placed via an all-inside arthroscopic technique delivering higher failure loads for meniscal root repair with little increase in surgical time.

Subregional Anatomical Distribution of T2 Values of Articular Cartilage in Asymptomatic Hips

OBJECTIVE

A standardized definition of normative T2 values across the articular surface of the hip must be defined in order to fully understand T2 values for detecting early degeneration. Therefore, in this article, we seek to lay foundational methodology for reproducible quantitative evaluation of hip cartilage damage using T2 mapping to determine the normative T2 values in asymptomatic individuals.

DESIGN

Nineteen prospectively enrolled asymptomatic volunteers (age 18-35 years, males 10, females 9, alpha angle 49.3º ± 7.2º) were evaluated with a sagittal T2 mapping sequence at 3.0 T magnetic resonance imaging. Acetabular and femoral cartilage was manually segmented directly on the second echo of the T2 mapping sequence by 3 raters, twice. Segmentations were divided into 12 subregions modified from the geographic zone method. Median T2 values within each subregion were compiled for further analysis and interrater and intrarater reliability was assessed.

RESULTS

In the femur, the posterior-superior subregion was significantly higher (P ≤ 0.05) than those in the posterior-inferior and anterior-inferior subregions. In the acetabulum, the anterior-inferior subregion was significantly higher (P ≤ 0.001) than in the anterior-superior, middle, and posterior-inferior subregions. T2 values of the posterior-superior subregion were significantly higher (P ≤ 0.05) than the anterior-superior, middle, and posterior-inferior subregions. Interrater agreement was generally fair to good.

MRI T2 mapping of the asymptomatic supraspinatus tendon by age and imaging plane using clinically relevant subregions

PURPOSE

Diagnosis of partial rotator cuff tears and tendonopathy using conventional MRI has proven variable. Quantitative T2 mapping may have application for assessing rotator cuff health. In order to evaluate the usefulness of T2 mapping for the rotator cuff, methods must be refined for mapping the supraspinatus tendon, and normative T2 values must first be acquired.

MATERIALS AND METHODS

This study was IRB approved. Thirty asymptomatic volunteers (age: 18-62) were evaluated with sagittal and coronal T2 mapping sequences. Manual segmentation of tendon and muscle as a unit and tendon alone was performed twice by two independent raters. Segmentations were divided into medial, middle and lateral subregions and mean T2 values calculated.

RESULTS

Anatomic comparison of mean T2 values illustrated highest values in the medial region, lowest values in the lateral region, and intermediate values for the middle region upon coronal segmentation (p<0.001). In sagittal segmentations, there were higher values in the medial region and no significant differences between the lateral and middle subregions. No significant differences were found with comparison across age groups. Inter and intra-rater segmentation repeatability was excellent, with coefficients ranging from 0.85 to 0.99.

CONCLUSION

T2 mapping illustrated anatomic variation along the supraspinatus muscle-tendon unit with low standard deviations and excellent repeatability, suggesting that changes in structure due to degeneration or changes associated with healing after repair may be detectable.

Effort thrombosis presenting as pulmonary embolism in a professional baseball pitcher

Context:

Effort thrombosis, or Paget-Schroetter’s syndrome, is a rare subset of thoracic outlet syndrome in which deep venous thrombosis of the upper extremity occurs as the result of repetitive overhead motion. It is occasionally associated with pulmonary embolism. This case of effort thrombosis and pulmonary embolus was in a 25-year-old major league professional baseball pitcher, in which the only presenting complaints involved dizziness and shortness of breath without complaints involving the upper extremity—usually, a hallmark of most cases of this condition. The patient successfully returned to play for 5 subsequent seasons at the major league level after multimodal treatment that included surgery for thoracic outlet syndrome.

Objective:

Though rare, effort thrombosis should be included in the differential diagnosis of throwing athletes with traditional extremity-focused symptoms and in cases involving pulmonary or thoracic complaints. Rapid diagnosis is a critical component of successful treatment.

Correlation of torque and elbow injury in professional baseball pitchers

BACKGROUND

During the pitching motion, velocity is generated by the upper extremity kinetic chain on internal rotation of the shoulder and trunk translational/rotational motion. This generation of power places significant forces and torques on the elbow and shoulder. Elbow valgus torque and shoulder rotational torque are theoretically linked to elbow injury.

HYPOTHESIS

Pitchers experiencing higher levels of elbow valgus torque and shoulder external rotation torque throughout the pitching motion are more likely to suffer elbow injury than pitchers with lower levels of torque.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

With an established biomechanical analysis model, 23 professional baseball pitchers were videotaped during spring training games and followed prospectively for the next 3 seasons for elbow injury. A mixed statistical model using differences of least squares means and analysis of variance was used to analyze the association between elbow injury and torque levels throughout the pitching motion as well as at each major event within the pitching motion.

RESULTS

There were overall statistical trends relating elbow injury with both higher elbow valgus torque (P = .0547) and higher shoulder external rotation torque (P = .0548) throughout the entire pitching motion. More importantly, there was an individual significant correlation of elbow injury with both higher elbow valgus torque (P = .0130) and higher shoulder external rotation torque (P = .0018) at the late cocking phase (pitching event of maximum external rotation of the shoulder).

CONCLUSION

This study provides information that supports existing theories about how and why certain injuries occur during the throwing motion in baseball. The late cocking phase appears to be the critical point in the pitching motion, where higher levels of torque at the shoulder and elbow can result in increased risk of injury. Manipulation of pitching mechanics to alter these torque levels or using these measures to identify pitchers at risk may help decrease injury rates.

Association of maximum pitch velocity and elbow injury in professional baseball pitchers

BACKGROUND

Recent literature has explored the association of upper extremity injury in baseball players with various aspects of the pitching motion. To our knowledge, no study has directly evaluated the connection between maximum pitch velocity and elbow injury in professional baseball pitchers.

HYPOTHESIS

Professional pitchers throwing at higher maximum ball velocity will have a higher risk of elbow injury.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Twenty-three professional pitchers were analyzed during spring training games and the ball velocity of the fastest pitch thrown for a strike (maximum pitch velocity) was recorded. This group was then followed prospectively over the following 3 seasons for elbow injury significant enough to warrant inclusion on the disabled list and/or require surgery. The association between maximum pitch velocity and elbow injury was then analyzed using an unpaired Student t test.

RESULTS

There were 9 players with elbow injuries in the group of pitchers studied, including 4 pitchers with an elbow muscle strain and/or joint inflammation and 5 pitchers with an ulnar collateral ligament sprain or tear. Three of the ulnar collateral ligament injuries required surgery. For the 14 pitchers in the noninjured group, the mean pitch velocity was 38.09 m/s (+/-1.45) or 85.22 mph (+/-3.24). For the 9 players in the injured group, the mean pitch velocity was 39.88 m/s (+/-2.39) or 89.22 mph (+/-5.36). There was a statistically significant association between maximum ball velocity and elbow injury (P = .0354). The injured group had a longer average career length (9.7 years) than the noninjured group (6.5 years; P = .0248). The 3 pitchers with the highest maximum ball velocity had the injuries requiring surgery.

CONCLUSION

A statistically significant association between maximum pitch velocity and elbow injury was noted in this study, providing further support of existing theories about injury in baseball.

A method to measure acetabular metrics from three dimensional computed tomography pelvis reconstructions - biomed 2009

Acetabular dysplasia is a proposed cause of osteoarthritis of the hip and techniques to identify acetabular dysplasia are important in early diagnosis and prevention of osteoarthritis of the hip. The aim of this study is to develop a method to measure acetabular coverage and volume using computed tomography (CT) images. A software program was used to create three-dimensional models of the acetabulum and femoral head and measure the acetabular volume of each hip from CT images. The three-dimensional models of the acetabulum and femoral head were imported into a post-processing software program to determine the surface areas for the femoral head covered by the acetabulum and the acetabular area covering the femoral head. Using CT scans gathered from 35 individuals, the results of this study demonstrated that the two surface area measurements were linearly correlated with the acetabulum volume. Positive linear relationships with R-squared values of 0.53 and 0.64 were found when comparing the acetabulum volume with the surface area of the femoral head covered by the acetabulum and the surface area of the acetabular area covering the femoral head. The method presented in this study for measuring acetabular coverage and volume using CT images could be used for the development of a more reliable method of diagnosing acetabular dysplasia.

Venous thromboembolism in lower extremity arthroscopy

Venous thromboembolism (VTE) is a relatively rare complication of arthroscopic surgery of the lower extremity, but it does have the potential to result in significant morbidity and possible mortality. VTE has been reported to occur with knee arthroscopy, and guidelines for VTE prophylaxis before and after knee arthroscopy have been proposed. There are much fewer data regarding the incidence of VTE occurring after arthroscopy of the ankle and the hip. This article reviews the literature on the incidence, treatment, and prevention of VTE in association with arthroscopy of the lower extremity.