Most Orthopaedic Platelet-Rich Plasma Investigations Don't Report Protocols and Composition: An Updated Systematic Review.

PURPOSE: To systematically review the literature to assess the heterogeneity of platelet-rich plasma (PRP) preparation and composition reporting for the treatment of musculoskeletal/orthopaedic pathologies. METHODS: A systematic review was performed by searching PubMed, the Cochrane Library, and Embase to identify Level I and Level II studies from 2016 to 2022 that evaluated the use of PRP therapy for musculoskeletal pathologies. The search phrase used was "platelet-rich plasma clinical studies." Studies were assessed based on their reporting of the PRP preparation methods and reporting of PRP composition. RESULTS: One hundred twenty-four studies (in 120 articles) met inclusion criteria for analysis. Of these studies, 15 (12.1%) provided comprehensive reporting, including a clear, well-described, and reproducible preparation protocol that future investigators can follow. Thirty-three studies (26.6%) quantitatively reported the final PRP product composition. CONCLUSIONS: Among the studies using PRP for the treatment of musculoskeletal/orthopaedic pathologies, less than 20% provided a clear, well-described, and reproducible PRP preparation protocol, and only one-fourth of studies reported on the final PRP product composition. CLINICAL RELEVANCE: A diverse current reporting of PRP composition between studies provides a high heterogeneity of the term "PRP," which becomes a limitation for a comparison of studies using PRP.

Experts Achieve Consensus on a Majority of Statements Regarding Platelet-Rich Plasma Treatments for Treatment of Musculoskeletal Pathology.

PURPOSE: To establish consensus statements on platelet-rich plasma (PRP) for the treatment of musculoskeletal pathologies. METHODS: A consensus process on the treatment of PRP using a modified Delphi technique was conducted. Thirty-five orthopaedic surgeons and sports medicine physicians participated in these consensus statements on PRP. The participants were composed of representatives of the Biologic Association, representing 9 international orthopaedic and musculoskeletal professional societies invited due to their active interest in the study of orthobiologics. Consensus was defined as achieving 80% to 89% agreement, strong consensus was defined as 90% to 99% agreement, and unanimous consensus was indicated by 100% agreement with a proposed statement. RESULTS: There was consensus on 62% of statements about PRP. CONCLUSIONS: (1) PRP should be classified based on platelet count, leukocyte count, red blood count, activation method, and pure-plasma versus fibrin matrix; (2) PRP characteristics for reporting in research studies are platelet count, leukocyte count, neutrophil count, red blood cell count, total volume, the volume of injection, delivery method, and the number of injections; (3) the prognostic factors for those undergoing PRP injections are age, body mass index, severity/grade of pathology, chronicity of pathology, prior injections and response, primary diagnosis (primary vs postsurgery vs post-trauma vs psoriatic), comorbidities, and smoking; (4) regarding age and body mass index, there is no minimum or maximum, but clinical judgment should be used at extremes of either; (5) the ideal dose of PRP is undetermined; and (6) the minimal volume required is unclear and may depend on the pathology. LEVEL OF EVIDENCE: Level V, expert opinion.

Editorial Commentary: Cartilage Restoration Typically Requires Joint Optimization as Well as Local Cartilage Resurfacing to Achieve Best Outcomes: The 30,000 Foot View.

Successful resurfacing of the articular surface often requires surgical optimization of the joint environment, in addition to the cartilage restoration procedure. This is the 30,000-foot view theory, where surgical planning concentrates on changing the forces in the joint that may have led to the cartilage lesion by performing essential procedures, such as osteotomies; scar tissue releases and/or ligament lengthening; joint stabilization; or meniscus replacement. With this view, which cartilage procedure should I perform becomes a secondary question. This approach involves looking at the environment of the joint as a whole and can lead to improved outcomes. Recent research shows that treatment of bipolar cartilage lesions results in inferior outcomes compared with unipolar lesions. But experience shows that results may be improved when treating bipolar lesions by using a structural graft on one surface, such as an osteochondral allograft, and a cellular or particulate graft on the opposite surface rather than using two nonstructural grafts. Before the transplantation, the surgeon corrects the joint forces as a whole. Over the past 10 years, I have consistently seen the benefits of cartilage restoration procedures using techniques anywhere from autologous cellular grafts to large, structural osteochondral allografts. Finally, the 30,000 foot view also includes addressing modifiable patient factors, such as weight loss. For the most part, the results have been promising, achieving significantly improved patient response rates, defined as a minimal clinically important difference (or MCID).

A Biomechanical Comparison of All-Inside Versus Transtibial Meniscus Root Repair Techniques.

BACKGROUND: Meniscus root tears are associated with chondral injury, early degenerative change, and a high conversion rate to total knee arthroplasty. It is well-established that meniscus root tears lead to decreased femorotibial contact area, increased peak contact pressures, and increased stress on the articular cartilage. PURPOSE: To evaluate the biomechanical characteristics of the all-inside meniscus root repair procedure and compare it with the previously described transtibial technique. STUDY DESIGN: Controlled laboratory study. METHODS: Nine paired cadaveric knees were prepared by removing skin, subcutaneous tissues, quadriceps muscles, patella, and patellar tendon, while leaving the capsule in place. Pressure-mapping sensors were inserted, and specimens underwent compressive loading to obtain peak pressures, mean pressures, and femorotibial contact area in the medial and lateral compartments. Tests were performed as static compression tests with the knee locked at 0° of flexion. Compression testing was performed in 3 states: meniscus intact, meniscus root cut, and after meniscus root repair with an all-inside repair technique. Additionally, testing was completed on 9 pairs of cadaveric knees to compare stiffness and maximal load to failure between the all-inside and transtibial meniscus root repair techniques. RESULTS: In the medial compartment, there were significant increases in median peak pressures and median mean pressures in the root cut state as compared with the intact state (+636 kPA [95% CI, 246 to 1026] and +190 kPA [95% CI, 49 to 330], respectively). All-inside meniscus root repair restored median peak pressures and median mean pressures to approach those of the intact meniscus (+311 kPA [95% CI, -79 to 701] and +137 kPA [95% CI, -3 to 277]). In the lateral compartment, there were also significant increases in median peak pressures and median mean pressures in the root cut state as compared with the intact state (+718 kPA [95% CI, 246 to 1191] and +203 kPA [95% CI, 51 to 355]). All-inside meniscus root repair restored median peak pressures and median mean pressures such that they were not significantly different from the intact state (+322 kPA [95% CI, -150 to 795] and +18 kPA [95% CI, -134 to 171]). There was no difference between repair techniques regarding load to failure (P = .896). Transtibial meniscus root repair had significantly more stiffness (mean ± SD, 24.8 ± 9.3 N/mm) as compared with the all-inside meniscus root repair technique (13.6 ± 3.8 N/mm, P = .015). CONCLUSION: All-inside meniscus root repair reduced median peak and mean pressures to those of the native intact meniscus with the knee in extension in the cadaveric model. When compared with a transtibial meniscus root repair technique, all-inside repair demonstrated decreased stiffness and a similar load to failure. CLINICAL RELEVANCE: All-inside meniscus root repair restored mean and peak femorotibial pressures to those of the intact meniscus. Additionally, it offers a technically easier technique for management of meniscus root tears.

Acromioclavicular Joint Injuries in Sport.

ABSTRACT: Sport-related shoulder injuries, including disruptions to the acromioclavicular joint (ACJ), are common. An ACJ injury is classified by the degree and direction of the clavicle displacement. Although the diagnosis can be made clinically, standard radiographic views are important to determine the severity of the ACJ disruption and assess for concurrent injuries. The majority of ACJ injuries can be managed nonoperatively; however, surgical treatment is indicated in some cases. Long-term outcomes are generally favorable for most ACJ injuries, and athletes generally return to sport without functional limitations. This article provides an in-depth discussion regarding all aspects of ACJ injuries, including clinically relevant anatomy, biomechanics, evaluation, treatment, and complications.

Regulatory and Ethical Aspects of Orthobiologic Therapies.

Orthobiologic therapies show significant promise to improve outcomes for patients with musculoskeletal pathology. There are considerable research efforts to develop strategies that seek to modulate the biological environment to promote tissue regeneration and healing and/or provide symptomatic relief. However, the regulatory pathways overseeing the clinical translation of these therapies are complex, with considerable worldwide variation. The introduction of novel biologic treatments into clinical practice raises several ethical dilemmas. In this review, we describe the process for seeking approval for biologic therapies in the United States, Europe, and Japan. We highlight a number of ethical issues raised by the clinical translation of these treatments, including the design of clinical trials, monitoring outcomes, biobanking, "off-label" use, engagement with the public, marketing of unproven therapies, and scientific integrity.

Nonsurgical Management of Osteoarthritis of the Knee: What You Should Be Injecting Now and in the Future.

Osteoarthritis of the knee affects many Americans. With the aging of the population and increasing comorbidities (eg, obesity, diabetes, hypertension, heart disease), the use of oral or topical NSAIDs is often contraindicated. Injectable treatment options are advantageous because of the ability to decrease or avoid the unwanted systematic adverse effects of NSAIDs. Injectable treatment options for osteoarthritis of the knee go back to the 1950s, beginning with corticosteroids, which remain widely used despite concerns that they may have adverse effects on articular chondrocytes and short duration of efficacy. The recent (FDA approval in 2017) introduction of a sustained-release corticosteroid (triamcinolone acetonide extended-release) offers significantly longer benefit than standard cortisone products and with substantially lower concentration levels of chondrocyte exposure to the steroid. Hyaluronic acid was added to the options for intra-articular injection in osteoarthritis of the knee in the late 1990s and remains widely used despite some controversy over its efficacy. Although guidelines for the use of hyaluronic acid for management of osteoarthritis of the knee have varied widely, careful analysis of the data and patient's perceived efficacy indicate its continued and important role in managing osteoarthritis of the knee. Finally, the past 15 years have seen an explosion in the use of biologics including platelet-rich plasma and pluripotential (often termed stem) cells. The science behind their use and efficacy is evolving and continued study is warranted.

Predictors of Mid- to Long-Term Outcomes in Patients Experiencing a Knee Dislocation: A Systematic Review of Clinical Studies.

Knee dislocations (KDs) are devastating injuries for patients and present complex challenges for orthopaedic surgeons. Although short-term outcomes have been studied, there are few long-term outcomes of these injuries available in the literature. The purpose of this study is to determine factors that influence mid- to long-term clinical outcomes following surgical treatment of KD. A review of the current literature was performed by searching PubMed, the Cochrane Library, and Embase to identify clinical studies published from 2010 to 2019 with a minimum 2-year follow-up that reported outcomes following surgical treatment of KDs. Ten studies (6 level III, 4 level IV) were included. At mid- (2-10 y) to long-term (>10 y) follow-up, concomitant arterial, cartilage, and combined meniscus damage were predictive factors for inferior Lysholm and International Knee Documentation Committee (IKDC) scores when compared with patients without these associated injuries. Although concomitant neurological damage may influence short-term outcomes due to decreased mobility, at longer follow-up periods it does not appear to predict worse clinical outcomes when compared with patients without concomitant neurological injury. Frank and polytrauma KDs have been associated with worse mid- to long-term outcomes when compared with transient and isolated KDs. Patients who underwent surgery within 6 weeks of trauma experienced better long-term outcomes than those who underwent surgery longer than 6 weeks after the initial injury. However, the small sample size of this study makes it difficult to make valid recommendations. Lastly, female sex, patients older than 30 years at the time of injury and a body mass index (BMI) greater than 35 kg/m2 are factors that have been associated with worse mid- to long-term Lysholm and IKDC scores. The results of this review suggest that female sex, age >30 years, BMI >35 kg/m2, concomitant cartilage damage, combined medial and lateral meniscal damage, KDs that do not spontaneously relocate, and KDs associated with polytrauma may predict worse results at mid- to long-term follow-up.

Platelet-Rich Plasma Versus Hyaluronic Acid for Hip Osteoarthritis Yields Similarly Beneficial Short-Term Clinical Outcomes: A Systematic Review and Meta-analysis of Level I and II Randomized Controlled Trials.

PURPOSE: To systematically review the literature to compare the efficacy of platelet-rich plasma (PRP) and hyaluronic acid (HA) injections for the treatment of hip osteoarthritis (OA). METHODS: A systematic review was performed by searching PubMed, the Cochrane Library, and Embase to identify randomized controlled trials that compared the clinical efficacy of PRP and HA injections for hip OA. The search phrase used was hip, osteoarthritis, platelet-rich plasma, hyaluronic acid, randomized. Patients were assessed based on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Visual Analog Scale (VAS) for pain, and the Harris Hip Score (HHS). Subanalyses were performed for any outcome score in which ≥3 studies reported results. RESULTS: Six studies (5 level I, 1 level II) met inclusion criteria, including 211 patients undergoing intra-articular injection with PRP (mean age 60.0 years, mean follow-up 12.2 months) and 197 patients with HA (mean age 62.3 years, mean follow-up 11.9 months). No significant differences were found in the weighted improvement of any outcome score (WOMAC, VAS, or HHS) from preinjection to postinjection between groups. When excluding a study with the highest risk of bias to eliminate heterogeneity, pooled subanalysis demonstrated no significant differences in WOMAC subscores between PRP and HA groups. Similarly, in a pooled subanalysis that isolated patients treated with leukocyte-poor PRP, no significant differences in WOMAC subscores were found between PRP and HA groups. CONCLUSION: Patients undergoing treatment for hip OA with either PRP or HA injections can expect to experience similarly beneficial short-term clinical outcomes. LEVEL OF EVIDENCE: II, systematic review of level I and II studies.

Cartilage Matrix Degeneration Occurs within the First Year after ACLR and Is Associated with Impaired Clinical Outcome.

OBJECTIVE: Anterior cruciate ligament reconstruction (ACLR) has not been shown to decrease the risk for development of post-traumatic osteoarthritis. Magnetic resonance imaging (MRI) T2 mapping can be used to assess cartilage compositional changes. This study tests whether (1) worse cartilage arthroscopic status at ACLR is reflected by higher cartilage T2 values in matched study regions 6 weeks and 1 year after ACLR, and (2) increasing cartilage T2 values between 6 weeks and 1 year after ACLR are associated with worsening patient-reported outcomes. DESIGN: Twenty-two participants with ACLR and 26 controls underwent 3T MRI. T2 values in medial and lateral femoral and tibial cartilage were measured at 6 weeks and 1 year after ACLR and compared with arthroscopic grades, Knee injury and Osteoarthritis Outcome Scores (KOOS), and control T2 values. RESULTS: Most (59%-86%) cartilage study regions examined by arthroscopy demonstrated intact articular surfaces. Average T2 value increased in 3 of 4 study regions between 6 weeks and 1 year after ACLR (P = .001-.011). T2 value increased (P < .013) even for participants whose cartilage had intact articular surfaces at ACLR. Participants with ACLR who showed greater increases in cartilage T2 values had less improvement to KOOS Quality of Life (P = .009, ρ = -0.62). DISCUSSION: Cartilage status assessed arthroscopically at ACLR and by MRI T2 maps 6 weeks later was healthier than cartilage status assessed by MRI T2 maps at 1-year follow-up. Progressive T2 elevations were observed over the first year after ACLR even in patients with arthroscopically intact cartilage at the time of surgery and were associated with reduced improvement in knee quality of life suggesting preosteoarthritis.

Single-cell transcriptomic profiling reveals distinct mechanical responses between normal and diseased tendon progenitor cells.

Regenerative medicine approaches utilizing stem cells offer a promising strategy to address tendinopathy, a class of common tendon disorders associated with pain and impaired function. Tendon progenitor cells (TPCs) are important in healing and maintaining tendon tissues. Here we provide a comprehensive single cell transcriptomic profiling of TPCs from three normal and three clinically classified tendinopathy samples in response to mechanical stimuli. Analysis reveals seven distinct TPC subpopulations including subsets that are responsive to the mechanical stress, highly clonogenic, and specialized in cytokine or growth factor expression. The single cell transcriptomic profiling of TPCs and their subsets serves as a foundation for further investigation into the pathology and molecular hallmarks of tendinopathy in mechanical stimulation conditions.

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.

Comparing Intra-articular Injections of Leukocyte-Poor Platelet-Rich Plasma Versus Low-Molecular Weight Hyaluronic Acid for the Treatment of Symptomatic Osteoarthritis of the Hip: A Double-Blind, Randomized Pilot Study.

BACKGROUND: Hyaluronic acid (HA) and leukocyte-poor platelet-rich plasma (LP-PRP) are 2 nonoperative treatment options that have been studied in patients with hip osteoarthritis (OA). PURPOSE: To compare the efficacy of intra-articular injections of low-molecular weight (LMW) HA and LP-PRP in patients with hip OA. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: A total of 34 patients (36 hips) presenting with signs of hip OA were randomized to receive 3 blinded, weekly intra-articular injections of either LP-PRP or LMW-HA. Patients were prospectively evaluated before injections and at 6 weeks and then at 3, 6, 12, and 24 months. The primary outcome, conversion to total hip arthroplasty (THA) or a hip resurfacing procedure, was analyzed along with secondary outcomes including the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score and hip range of motion. RESULTS: The final analysis included 33 hips (mean Kellgren-Lawrence grade, 2.73) (LMW-HA: n = 14; LP-PRP: n = 19) in 31 patients (18 male; mean age, 53.8 years). Significantly more patients converted to THA or a hip resurfacing procedure in the LMW-HA group (7/14; 50.0%) (mean, 1.3 years after first injection) than the LP-PRP group (3/19; 15.8%) (mean, 0.73 years after first injection) (P = .035). There was no significant improvement or decline in any outcome scores within the LMW-HA group from before injections to 6 weeks or 3, 6, and 12 months. For the LP-PRP group, WOMAC overall (P = .032), joint (P = .030), and function scores (P = .025) significantly improved from before injections to 6 weeks, and WOMAC joint scores significantly improved from before injections to 6 months (P = .036). When comparing the difference between groups in internal rotation at 90° of hip flexion from before injections to 6 months, the LP-PRP group demonstrated a mean 5.0° improvement, while the LMW-HA group showed a mean 1.5° decrease (P = .028). CONCLUSION: Intra-articular hip injections of LP-PRP in patients with hip OA resulted in an improvement in WOMAC scores and hip internal rotation at 6 months and delayed the need for THA or a hip resurfacing procedure compared with treatment with LMW-HA. A longer follow-up is necessary to further compare the effects of LP-PRP and LMW-HA injections in patients with hip OA. REGISTRATION: NCT01920152 (ClinicalTrials.gov identifier).

T2 relaxation times of knee cartilage in 109 patients with knee pain and its association with disease characteristics.

Background and purpose - Quantitative T2 mapping MRI of cartilage has proven value for the assessment of early osteoarthritis changes in research. We evaluated knee cartilage T2 relaxation times in a clinical population with knee complaints and its association with patients and disease characteristics and clinical symptoms.Patients and methods - In this cross-sectional study, T2 mapping knee scans of 109 patients with knee pain who were referred for an MRI by an orthopedic surgeon were collected. T2 relaxation times were calculated in 6 femoral and tibial regions of interest of full-thickness tibiofemoral cartilage. Its associations with age, sex, BMI, duration of complaints, disease onset (acute/chronic), and clinical symptoms were assessed with multivariate regression analysis. Subgroups were created of patients with abnormalities expected to cause predominantly medial or lateral tibiofemoral cartilage changes.Results - T2 relaxation times increased statistically significantly with higher age and BMI. In patients with expected medial cartilage damage, the medial femoral T2 values were significantly higher than the lateral; in patients with expected lateral cartilage damage the lateral tibial T2 values were significantly higher. A traumatic onset of knee complaints was associated with an acute elevation. No significant association was found with clinical symptoms.Interpretation - Our study demonstrates age, BMI, and type of injury-dependent T2 relaxation times and emphasizes the importance of acknowledging these variations when performing T2 mapping in a clinical population.

Effects of unloader bracing on clinical outcomes and articular cartilage regeneration following microfracture of isolated chondral defects: a randomized trial.

PURPOSE: To determine whether the use of an unloading brace can increase the thickness of cartilage regenerate after microfracture surgery. METHODS: This is a randomized (1:1) controlled clinical trial. Twenty-four patients who underwent microfracture between 2012 and 2015 were identified and were randomly assigned to an unloading brace group or a no-brace group. All patients were kept non-weight bearing for the first eight weeks after surgery and then patients in the intervention group began using an unloading brace for an average of 63.9 (SD = 41.6) days to protect clot stability by exerting a varus or valgus force on the knee to decrease the force on the knee's lateral or medial compartment, respectively. Quality of the cartilage repair was assessed with knee magnetic resonance imaging to determine repair tissue thickness (primary outcome), repair tissue volume, and T2 relaxation times at 12 and 24 months after surgery. Clinical outcomes were evaluated with KOOS, Tegner, SF12, and Lysholm questionnaires at six, 12 and 24 months after surgery. RESULTS: Three patients were lost to follow-up, resulting in 21 patients ultimately analyzed. The unloading brace repair tissue was greater than the no-brace group in volume (26.8 ± 23.7 mm3 vs - 8.4 ± 22.7 mm3, p = 0.005) and thickness (0.2 ± 0.2 mm versus - 0.4 ± 0.3 mm, p = 0.001) at 12 months and in cartilage thickness in the unloading brace group at 24 months (0.4 ± 0.4 mm versus - 0.1 ± 0.3 mm, p = 0.029). There was a positive correlation between wearing the brace longer and improved 6-month KOOS symptom scores (r = 0.82, p = 0.013), 6-month KOOS QOL scores (r = 0.80, p = 0.017), 6-month Tegner scores (r = 0.94, p = 0.002), and Tegner score changes from baseline to 6 months (r = 0.80, p = 0.032). CONCLUSION: This study found a significant mid-term increase in cartilage repair tissue thickness following unloading bracing in patients recovering from microfracture for isolated chondral defects. LEVEL OF EVIDENCE: II.

Platelet-Rich Plasma Versus Hyaluronic Acid for Knee Osteoarthritis: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

BACKGROUND: Platelet-rich plasma (PRP) and hyaluronic acid (HA) are 2 nonoperative treatment options for knee osteoarthritis (OA) that are supposed to provide symptomatic relief and help delay surgical intervention. PURPOSE: To systematically review the literature to compare the efficacy and safety of PRP and HA injections for the treatment of knee OA. STUDY DESIGN: Meta-analysis of level 1 studies. METHODS: A systematic review was performed by searching PubMed, the Cochrane Library, and Embase to identify level 1 studies that compared the clinical efficacy of PRP and HA injections for knee OA. The search phrase used was platelet-rich plasma hyaluronic acid knee osteoarthritis randomized. Patients were assessed via the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), visual analog scale (VAS) for pain, and Subjective International Knee Documentation Committee (IKDC) scale. A subanalysis was also performed to isolate results from patients who received leukocyte-poor and leukocyte-rich PRP. RESULTS: A total of 18 studies (all level 1) met inclusion criteria, including 811 patients undergoing intra-articular injection with PRP (mean age, 57.6 years) and 797 patients with HA (mean age, 59.3 years). The mean follow-up was 11.1 months for both groups. Mean improvement was significantly higher in the PRP group (44.7%) than the HA group (12.6%) for WOMAC total scores (P < .01). Of 11 studies based on the VAS, 6 reported PRP patients to have significantly less pain at latest follow-up when compared with HA patients (P < .05). Of 6 studies based on the Subjective IKDC outcome score, 3 reported PRP patients to have significantly better scores at latest follow-up when compared with HA patients (P < .05). Finally, leukocyte-poor PRP was associated with significantly better Subjective IKDC scores versus leukocyte-rich PRP (P < .05). CONCLUSION: Patients undergoing treatment for knee OA with PRP can be expected to experience improved clinical outcomes when compared with HA. Additionally, leukocyte-poor PRP may be a superior line of treatment for knee OA over leukocyte-rich PRP, although further studies are needed that directly compare leukocyte content in PRP injections for treatment of knee OA.

Biomechanical Testing of Suture Anchor Versus Transosseous Tunnel Technique for Quadriceps Tendon Repair Yields Similar Outcomes: A Systematic Review.

PURPOSE: To systematically review the literature to evaluate the biomechanical properties of the suture anchor (SA) versus transosseous tunnel (TO) techniques for quadriceps tendon (QT) repair. METHODS: A systematic review was performed by searching PubMed, the Cochrane Library, and Embase using PRISMA guidelines to identify studies that evaluated the biomechanical properties of SA and TO techniques for repair of a ruptured QT. The search phrase used was "quadriceps tendon repair biomechanics". Evaluated properties included ultimate load to failure (N), displacement (mm), stiffness (N/mm), and mode of failure. RESULTS: Five studies met inclusion criteria, including a total of 72 specimens undergoing QT repair via the SA technique and 42 via the TO technique. Three of 4 studies found QTs repaired with SA to have significantly less elongation upon initial cyclic loading when compared to QTs repaired with the TO technique (P < .05). Three of 5 studies found QTs repaired with SA to have significantly less elongation upon final cyclic loading when compared to QTs repaired with the TO technique (P < .05). The pooled analysis from 4 studies reporting on initial displacement showed a statistically significant difference in favor of the SA group compared to the TO group (P = .03). The pooled analysis from studies reporting on secondary displacement and ultimate load to failure showed no significant difference between the SA and TO groups (P > .05). The most common mode of failure in both groups was suture slippage. CONCLUSION: On the basis of the included cadaveric studies, QTs repaired via the SA technique have less initial displacement upon cyclic testing when compared to QTs repaired via the TO technique. However, final displacement and ultimate load to failure outcomes did not reveal differences between the two fixation strategies. Knot slippage remains a common failure method for both strategies.

Tranexamic Acid Use in Knee and Shoulder Arthroscopy Leads to Improved Outcomes and Fewer Hemarthrosis-Related Complications: A Systematic Review of Level I and II Studies.

PURPOSE: To systematically review the literature to compare the efficacy and safety of tranexamic acid (TXA) as a means to minimize hemarthrosis-related complications after arthroscopic procedures of the knee, hip, and shoulder. METHODS: A systematic review according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was performed by searching PubMed, Cochrane Library, and Embase databases to locate randomized controlled trials comparing the clinical outcomes and postoperative complications of patients undergoing arthroscopy with and without TXA. Search terms used were "tranexamic acid," "arthroscopy," "knee," "hip," and "shoulder." Patients were evaluated based on early (<6 weeks) postoperative signs of hemarthrosis using the Coupens and Yates classification, postoperative complications (myocardial infarction, stroke, venous thromboembolism events), range of motion (ROM), and patient-reported outcome scores (Visual analog scale, Subjective International Knee Documentation Committee, Lysholm, and Tegner activity scores). RESULTS: Five studies (2 level I and 3 level II) met inclusion criteria, including a total of 299 patients undergoing arthroscopy with TXA and 299 patients without TXA. The average follow-up duration for all patients was 43.9 days. Procedures performed were partial meniscectomy, anterior cruciate ligament reconstruction, and rotator cuff repair. No studies evaluating TXA use in hip arthroscopy were identified. Coupens-Yates hemarthrosis grades significantly improved in the TXA groups across all studies. Three studies found TXA patients to experience significantly less postoperative pain at latest follow-up, 1 study found TXA patients to have significantly better postoperative Lysholm scores, and 1 study found TXA patients to have significantly more ROM at latest follow-up compared with non-TXA patients (P < .05). CONCLUSION: Patients undergoing arthroscopy, particularly arthroscopic meniscectomy, arthroscopic-assisted anterior cruciate ligament reconstruction, and arthroscopic rotator cuff repair, with TXA can be expected to experience improved outcomes and less hemarthrosis-related complications in the early postoperative period compared with non-TXA patients. LEVEL OF EVIDENCE: II, systematic review of level I and II studies.

A Genome-wide Association Study for Concussion Risk.

PURPOSE: This study aimed to screen the entire genome for genetic markers associated with risk for concussion. METHODS: A genome-wide association analyses was performed using data from the Kaiser Permanente Research Bank and the UK Biobank. Concussion cases were identified based on electronic health records from the Kaiser Permanente Research Bank and the UK Biobank from individuals of European ancestry. Genome-wide association analyses from both cohorts were tested for concussion using a logistic regression model adjusting for sex, height, weight, and race/ethnicity using allele counts for single nucleotide polymorphisms. Previously identified genes within the literature were also tested for association with concussion. RESULTS: There were a total of 4064 cases of concussion and 291,472 controls within the databases, with two single nucleotide polymorphisms demonstrating a genome-wide significant association with concussion. The first polymorphism, rs144663795 (P = 9.7 × 10-11; OR = 2.91 per allele copy), is located within the intron of SPATA5. Strong, deleterious mutations in SPATA5 cause intellectual disability, hearing loss, and vision loss. The second polymorphism, rs117985931 (P = 3.97 × 10-9; OR = 3.59 per allele copy), is located within PLXNA4. PLXNA4 plays a key role is axon outgrowth during neural development, and DNA variants in PLXNA4 are associated with risk for Alzheimer's disease. Previous investigations have identified five candidate genes that may be associated with concussion, but none showed a significant association in the current model (P < 0.05). CONCLUSION: Two genetic markers were identified as potential risk factors for concussion and deserve further validation and investigation of molecular mechanisms.