➤ Orthobiologics encompass numerous substances that are naturally found in the human body including platelet-rich plasma (PRP), isolated growth factors, and cell therapy approaches to theoretically optimize and improve the healing of cartilage, fractures, and injured muscles, tendons, and ligaments. ➤ PRP is an autologous derivative of whole blood generated by centrifugation and is perhaps the most widely used orthobiologic treatment modality. Despite a vast amount of literature on its use in osteoarthritis as well as in tendon and ligament pathology, clinical efficacy results remain mixed, partly as a result of insufficient reporting of experimental details or exact compositions of PRP formulations used. ➤ Mesenchymal stromal cells (MSCs) can be isolated from a variety of tissues, with the most common being bone marrow aspirate concentrate. Similar to PRP, clinical results in orthopaedics with MSCs have been highly variable, with the quality and concentration of MSCs being highly contingent on the site of procurement and the techniques of harvesting and preparation. ➤ Advances in novel orthobiologics, therapeutic targets, and customized orthobiologic therapy will undoubtedly continue to burgeon, with some early promising results from studies targeting fibrosis and senescence.

There are no reports in the literature describing risk factors for failure of nonoperative treatment of patients with posterior labral tears on magnetic resonance imaging (MRI). The purpose of this study is to identify risk factors for failure of nonoperative treatment in patients with an isolated posterior glenoid labral tear identified on MRI only. Patients with posterior labral tears on MRI who fail to improve with nonoperative treatment likely share a constellation of clinical history, physical exam, and radiographic findings. One hundred and fifty-nine active duty military service members under the age of 40 with a posterior labral tear seen on MRI and who were clinically evaluated by a musculoskeletal trained physician were identified. We retrospectively evaluated their records ensuring a minimum of 2 years follow-up after MRI to identify surgical intervention for the posterior labral tear during this time period. Patients were stratified into two groups, those treated with any combination of nonoperative modalities and those treated with posterior labral repair surgery during the 2 years after the MRI. The electronic medical records were reviewed for clinical presentation and physical exam results. We measured multiple radiographic parameters, including glenoid version, size of the tear, and bone loss on MRI. Qualitative and quantitative data were compared between groups using Fisher’s exact test and Student’s t-test, respectively. This study was conducted under institutional review board approval. Of the 157 patients’ shoulders in our study, 52% (n = 82) of patients with posterior labral tears underwent nonoperative treatment while 48% (n = 75) underwent surgery. The significant risk factors associated with surgery were a history of a specific injury, primary presenting complaint of instability, patient reported history of subluxation, inability to trust their shoulder with overhead activity, decreased strength with weight lifting, positive posterior load/shift exam, positive anterior apprehension, increased osseous glenoid retroversion, increased humeral head subluxation ratio, and anterior labral height (P < 0.05). Patients with a chief complaint of pain were much more likely to succeed with nonoperative treatment while those with instability underwent surgery more often. Ten (12.5%) of the surgical procedures included an anterior and posterior labral repair/stabilization procedure. Patients with an MRI confirmed posterior labral tear, which present with subjective complaints and physical exam maneuvers consistent with instability, appear less likely to be treated nonoperatively. Increased glenoid retroversion and posterior humeral head subluxation may also predispose patients toward surgical treatment. Additionally, posterior labral tears may extend into the anterior labrum more frequently than is recognized on MRI.

Background: Existing biomechanical studies of posterior glenoid bone loss and labral pathology are limited by their use of anterior instability models, which differ in both orientation and morphology and have been performed in only a single, neutral arm position. Purpose: To evaluate the biomechanical effectiveness of a posterior labral repair in the setting of a clinically relevant posterior bone loss model in various at-risk arm positions. Study Design: Controlled laboratory study. Methods: Ten fresh-frozen cadaveric shoulders were tested in 7 consecutive states using a 6 degrees of freedom robotic arm: (1) native, (2) posterior labral tear (6-9 o’clock), (3) posterior labral repair, (4) mean posterior glenoid bone loss (7%) with labral tear, (5) mean posterior glenoid bone loss with labral repair, (6) large posterior glenoid bone loss (28%) with labral tear, and (7) large posterior glenoid bone loss with labral repair. Bone loss was created using 3-dimensional printed computed tomography model templates. Biomechanical testing consisted of 75 N of posterior-inferior force and 75 N of compression at 60° and 90° of flexion and scaption. Posterior-inferior translation, lateral translation, and peak dislocation force were measured for each condition. Results: Labral repair significantly increased dislocation force independent of bone loss state between 10.1 and 14.8 N depending on arm position. Dislocation force significantly decreased between no bone loss and small bone loss (11.9-13.5 N), small bone loss and large bone loss (9.4-14.3 N), and no bone loss and large bone loss (21.2-26.5 N). Labral repair significantly decreased posterior-inferior translation compared with labral tear states by a range of 1.0 to 2.3 mm. In the native state, the shoulder was most unstable in 60° of scaption, with 29.9 ± 6.1-mm posterior-inferior translation. Conclusion: Posterior labral repair improved stability of the glenohumeral joint, and even in smaller to medium amounts of posterior glenoid bone loss the glenohumeral stability was maintained with labral repair in this cadaveric model. However, a labral repair with large bone loss could not improve stability to the native state. Clinical Relevance: This study shows that larger amounts of posterior glenoid bone loss (>25%) may require bony augmentation for adequate stability.

Background: Senescence, a characteristic of cellular aging and inflammation, has been linked to the acceleration of osteoarthritis. The purpose of this study is to prospectively identify, measure, and compare senescent profiles in synovial fluid and peripheral blood in patients with an acute knee injury within 48 h. Methods: Seven subjects, aged 18–60 years, with an acute ACL tear with effusion were prospectively enrolled. Synovial fluid and peripheral blood samples were collected and analyzed by flow cytometry, using senescent markers C12FDG and CD87. The senescent versus pro-regenerative phenotype was probed at a gene and protein level using qRT-PCR and multiplex immunoassays. Results: C₁₂FDG and CD87 positive senescent cells were detected in the synovial fluid and peripheral blood of all patients. Pro-inflammatory IL-1β gene expression measured in synovial fluid was significantly higher (p = 0.0156) than systemic/blood expression. Senescent-associated factor MMP-3 and regenerative factor TIMP-2 were significantly higher in synovial fluid compared to blood serum. Senescent-associated factor MMP-9 and regenerative factor TGFβ-2 were significantly elevated in serum compared to synovial fluid. Correlation analysis revealed that C12FDG⁺⁺/CD87⁺⁺ senescent cells in synovial fluid positively correlated with age-related growth-regulated-oncogene (ρ = 1.00, p < 0.001), IFNγ (ρ = 1.00, p < 0.001), IL-8 (ρ = 0.90, p = 0.0374), and gene marker p16 (ρ = 0.83, p = 0.0416). Conclusions: There is an abundance of senescent cells locally and systemically after an acute ACL tear without a significant difference between those present in peripheral blood compared to synovial fluid. This preliminary data may have a role in identifying strategies to modify the acute environment within the synovial fluid, either at the time of acute ligament injury or reconstruction surgery.

Osteoarthritis (OA) of the knee joint is the most common chronic degenerative joint disease characterized by cartilage deterioration and inflammation. Conservative management to prevent cartilage degradation and future conversion to joint replacement has been the focus of attention, with a number of orthobiologics being applied clinically. Among them, bone marrow aspirate concentrate (BMAC) has been growing in popularity as a source of mesenchymal stem cells (MSC) and growth factors with regenerative capacity as well as anti-inflammatory properties. As it pertains to OA, the anti-inflammatory and regenerative effects of BMAC are promising, although, continued research and standardization of treatment are still necessary. This article aims to provide a review of the characteristics of BMAC from a regenerative medicine perspective and provide a current summary of the preclinical and clinical results of BMAC when utilized to treat OA of the knee joint.

Background: Biomechanical studies have demonstrated improved loading properties and tissue tear-through of suture tapes as compared with suture, suggesting that a tape construct in labral repair may reduce failure rates. However, comparative clinical studies are lacking. Purpose/Hypothesis: The purpose was to determine the rate of recurrent instability after arthroscopic stabilization and compare survivability and risk factors for failure in a persistently high-demand military population. The null hypothesis was that there would be no difference between the failure rates of arthroscopic stabilization procedures when utilizing a suture tape construct as compared with suture for all instability patterns. Study Design: Case-control study; Level of evidence, 3. Methods: The authors retrospectively reviewed all shoulder stabilization procedures performed by 3 fellowship-trained sports surgeons at a single high-volume military facility from 2010 to 2020. Given the purported benefits of tape constructs, the surgeons at this facility transitioned from knotted suture to knotless suture tape constructs in 2015. Patients were included who underwent arthroscopic labral repair with minimum 2-year follow-up. Descriptive data, prior instability events, surgical details, and revision procedures were recorded. Intraoperative details included size and location of the tear, concurrent lesions, number and type of anchors, and suture type used. Glenoid bone loss was measured using the circle method, and the Hills-Sachs index was used to evaluate for the presence of off-track lesions. The primary outcome was repair failure. Survival analysis and univariate and multivariate logistic regression analyses were performed by instability pattern groups to identify factors most associated with failure. Results: A total of 448 procedures were identified, of which 163 anterior, 51 posterior, and 111 combined labral repairs were analyzed. Median follow-up was >6.5 years across groups. On univariate analysis for posterior instability, the use of a knotless suture tape construct was associated with a lower chance of failure when compared with knotted suture constructs (0% vs 20.6%; P = .044). On multivariate analysis accounting for other confounding factors, the use of knotless suture tape was associated with a lower odds of failure (anterior repair: odds ratio [OR], 0.58 [ P = .042]; combined repair: OR, 0.22 [ P = .025]), while glenoid bone loss >10% was associated with failure after anterior repairs (OR, 3.91; P = .038). Conclusion: In a young, at-risk military population undergoing primary arthroscopic labral repair, the use of knotless suture tape was associated with decreased failure regardless of instability pattern.