Editorial Commentary: Anterior Shoulder Instability in Adolescent Athletes: "Slaying the Hydra" Is a Subtle Art.

Anterior shoulder instability in adolescent athletes can be cumbersome to identify and treat. An algorithm is to divide the patients into primary and revision cases then to further subdivide patients who have glenoid bone loss <20% and/or an engaging or off-track Hill-Sachs lesion. A bipolar lesion with either of these conditions is an indication for a bone block open Laterjet procedure. In the revision setting, the threshold for Laterjet is lower. Soft-tissue lesions are indications for a Bankart or labral repair. With the proper attention given to concomitant labral, biceps, and rotator cuff pathology, Hill-Sachs lesions less than 1 cm are left alone. However, in situations where lesions are deeper than 1 cm, an arthroscopic remplissage is indicated. An optimal repair aims to create a labral bumper and a bony bed for the soft tissue to heal, whereas inferior quality of soft tissue indicates a segmental labral reconstruction. Reconstructing large capsular rents with torn ligaments with allograft anterior capsular repair is also needed for proper biomechanical restoration.

Cell-free Stem Cell-Derived Extract Formulation for Regenerative Medicine Applications.

Stem cells for regenerative medicine purposes offer therapeutic benefits, but disadvantages are still ill defined. The benefit of stem cells may be attributed to their secretion of growth factors (GFs), cytokines (CKs), and extracellular vesicles (EVs), including exosomes. We present a novel cell-free stem cell-derived extract (CCM), formulated from human progenitor endothelial stem cells (hPESCs), characterized for biologically active factors using ELISA, nanoparticle tracking analysis and single particle interferometric reflectance imaging sensing. The effect on fibroblast proliferation and ability to induce stem cell migration was analyzed using Alamar Blue proliferation and Transwell migration assays, respectively. GFs including IGFBP 1, 2, 3, and 6, insulin, growth hormone, PDGF-AA, TGF-α, TGF-ß1, VEGF, and the anti-inflammatory cytokine, IL-1RA were detected. Membrane enclosed particles within exosome size range and expressing exosome tetraspanins CD81 and CD9 were identified. CCM significantly increased cell proliferation and induced stem cell migration. Analysis of CCM revealed presence of GFs, CKs, and EVs, including exosomes. The presence of multiple factors including exosomes within one formulation, the ability to promote cell proliferation and induce stem cell migration may reduce inflammation and pain, and augment tissue repair.

Intraosseous Bioplasty for a Subchondral Cyst in the Lateral Condyle of Femur.

Several conditions can lead to the development of a subchondral cyst. The mechanism by which the cysts form, their location, and their severity depend on the underlying pathology, although the exact pathogenesis is not fully elucidated. Treatment options vary according to the location of the cyst, with less invasive procedures such as calcium phosphate cement injection to a joint arthroplasty when there is an extensive cyst in communication with the joint space. If the cyst is circumscribed, an intraosseous bioplasty (IOBP) can be performed. Described in this paper is an IOBP, a minimally invasive technique that preserves the joint and can be applied to most subchondral cysts. In our patient, both the appearance of the cyst at imaging and pain after IOBP greatly improved with the combined use of decompression and grafting. In those patients in whom conservative management fails to ameliorate symptoms, IOBP should be considered.

Repair of Acute-on-Chronic Subscapularis Insufficiency in an Adolescent Athlete.

A 13-year-old right-hand-dominant skeletally immature boy presented to the authors' clinic after being blocked during an overhead dodgeball throw and hearing an abrupt "pop" in the shoulder. He had pain in the subdeltoid region that was most prominent during sports-related activity, particularly throwing. The patient had nonoperative management of a lesser tuberosity avulsion fracture 1 year earlier after a similar injury that occurred during a basketball game. He had returned to normal sporting activity 2 months before the most recent injury. Repeat advanced imaging showed an avulsion fracture of the subscapularis tendon, with a significantly retracted 2-cm component as well as a less retracted component, suggesting acute-on-chronic injury. Given this retraction and the symptoms during throwing, the patient was counseled that surgical management would best facilitate an asymptomatic return to sports-related activity. This case showed acute-on-chronic subscapularis tendon insufficiency with avulsion of the lesser tuberosity and significant retraction of the subscapularis tendon without tearing, a rare injury pattern in adolescents. For fixation of the avulsed lesser tuberosity fracture, an open approach technique was used in which SpeedBridge (Arthrex, Naples, Florida) sutures were passed behind the bone fragment. Four anchors were placed medial and lateral to the subscapularis insertion points to create a knotless double-row footprint. Compared with the published literature, this method of subscapularis fixation offered secure anatomic repair in a time-efficient, user-friendly manner.

Diagnosis and Management of Extra-articular Causes of Pain After Total Knee Arthroplasty.

Postoperative pain, which has been attributed to poor outcomes after total knee arthroplasty (TKA), remains problematic for many patients. Although the source of TKA pain can often be delineated, establishing a precise diagnosis can be challenging. It is often classified as intra-articular or extra-articular pain, depending on etiology. After intra-articular causes, such as instability, aseptic loosening, infection, or osteolysis, have been ruled out, extra-articular sources of pain should be considered. Physical examination of the other joints may reveal sources of localized knee pain, including diseases of the spine, hip, foot, and ankle. Additional extra-articular pathologies that have potential to instigate pain after TKA include vascular pathologies, tendinitis, bursitis, and iliotibial band friction syndrome. Patients with medical comorbidities, such as metabolic bone disease and psychological illness, may also experience prolonged postoperative pain. By better understanding the diagnosis and treatment options for extra-articular causes of pain after TKA, orthopaedic surgeons may better treat patients with this potentially debilitating complication.

Diagnosis and Management of Intra-articular Causes of Pain After Total Knee Arthroplasty.

Total knee arthroplasty (TKA) is an effective procedure for decreasing pain, improving functional capability, and increasing the overall quality of life for thousands of people with chronic knee osteoarthritis. Although patient outcomes and satisfaction remain high, a substantial percentage of patients report residual pain after TKA. Sources of postoperative pain include intra- and extra-articular etiologies as well as factors unrelated to the implants themselves. A patient-centered approach to the painful TKA may aid clinicians in diagnosing and treating patients with intra-articular causes of pain after TKA. A thorough understanding of the mechanisms involved may lead to improved preoperative planning and patient selection, ultimately decreasing the number of patients with less than optimal postoperative outcomes.