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Purpose: (1) To systematically review treatments for partial extensor mechanism tendon tears in professional and amateur athletes and (2) to report outcomes for patients undergoing operative versus nonoperative management. Methods: PubMed, Cochrane, Scopus, Google Scholar, and Web of Science were queried in August 2023 using the following Boolean search: (quadriceps OR patella) AND (partial) AND (tear). Articles were included if they reported outcomes of operative or nonoperative management of partial extensor mechanism tears of the knee in athletes. The review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analyses criteria. Each study was queried for demographics, tendon injured, sport and level of athlete, prior treatments, final treatment modality, and return to sport (RTS) outcomes of that treatment. A qualitative subanalysis was performed for professional athletes. Results: Ten studies met inclusion criteria and included 191 partial patellar or quadriceps tendon tears. Of the patients, 81.6% were male and 18.4% were female, with average age ranging from 21 to 28 years; 97% of patients underwent initial nonoperative management. Ultimately, 111 patients (58.1%) were maintained on nonoperative management, and 80 (41.9%) progressed to surgery. Of surgeries, 39 (48.8%) were tendon debridements, 36 (45.0%) were repairs, and 5 (6.3%) were not specified. RTS rates ranged from 33% to 93% after surgery and 70% to 89% following conservative management. Of professional athletes, 23 (33%) underwent surgery, and 46 (67%) underwent ultimate conservative management. RTS rates ranged from 33% to 67% after surgery and were 89% for the applicable study of conservative management. Conclusions: Nearly all patients with partial extensor mechanism tears underwent initial nonoperative management. RTS rates were high but somewhat variable among both patients treated with final nonoperative versus surgical management. Even among professional athletes, most injuries were treated with initial nonoperative management and did not progress to surgery. Level of Evidence: Level V, systematic review of Level IV and V studies.

We describe a combined all-inside, inside-out, and outside-in technique for the repair of unstable bucket-handle medial meniscal tears. Notably, a greater incidence of neurovascular complications has been associated with meniscal repair techniques that employ an accessory skin incision, especially when damage involves the body of the medial meniscus. However, with the operative knee in relative extension, passing inside-out needles anteromedial to the posterior horn and posterior to the semitendinosus tendon and saphenous nerve allows for the needles to exit the posteromedial knee through a “safe zone.” Therefore, we reduce iatrogenic damage by avoiding the necessity of a large safety incision while still maintaining suture placement versatility and meniscal fragment stabilization. Thus, the objective of this Technical Note is to outline an efficient technique for treating bucket-handle medial meniscal tears that yields a strong, durable repair while avoiding damage to adjacent neurovascular structures and eliminating the need for a posteromedial safety incision.

High-energy anterior cruciate ligament (high-energy ACL) injury, occurring in high-energy rotatory trauma of the knee, can accompany a unique fracture pattern that involves depression of the slope of the posterolateral tibial plateau (PLTP). These injuries are challenging to manage due to the lack of a gold-standard arthroscopic procedure that addresses both ACL deficiency and depressed PLTP slope. In such injuries, a one-stage approach may be used to (1) reconstruct the ACL or (2) reduce and fix the avulsed tibial spine, while concomitantly performing an arthroscopy-assisted reduction of a PLTP fracture that restores the anatomic slope of the tibial plateau. To summarize, using combined arthroscopic and fluoroscopic visualization, a tibial tunnel reaching 1 cm distal to the depressed plateau fragment is created using a cannulated drill. The drill is used to punch up the depressed fragment to its anatomic location, restoring the original slope of the PLTP. The corrected slope is then fixed in situ using a press-fit fibular allograft to stabilize the corrected PLTP slope. Use of this minimally invasive arthroscopic technique to restore the PLTP slope may help prevent graft failure of the reconstructed ACL and improve patient outcomes.

Pigmented villonodular synovitis (PVNS) is a monoarticular, benign tumor arising from the synovium. Although classically treated with open synovectomy, arthroscopic treatment has demonstrated good clinical outcomes. The arthroscopic management of hip PVNS has been described as technically challenging due to difficulty obtaining the appropriate exposure. The purpose of this technical report is to describe a novel technique that allows for sound excision of PVNS during hip arthroscopy using a puncture capsulotomy. Full visualization throughout the central and peripheral compartments is key to achieving meticulous surgical excision and ablation, with careful attention to the medial and lateral synovial folds and gutters. It is important to avoid chondral injury by using a high outflow rate of irrigation to maintain a constant temperature, to ablate the blood supply of nodular lesions, and to not use a shaver as this may disseminate tumor cells. Multifactorial advancements in hip arthroscopy have permitted adequate visualization and exposure of PVNS lesions, making them amenable to arthroscopic synovectomy. Puncture capsulotomy does not require capsular closure, preserves the iliofemoral ligament, and minimizes exposure of extra-articular structures to the hip joint environment. Recurrence rates are lower in arthroscopic management compared with open management, at 7.7% and 17.8%, respectively.

Despite advances in techniques for acetabular labral repair, strategies for mitigating or reversing damage to the chondrolabral junction do not yet exist. Cartilage repair techniques such as autologous chondrocyte implantation, matrix-induced autologous chondrocyte implantation, osteochondral autograft transfer, microfracture, and bone marrow aspirate concentrate (BMAC) have all been suggested to restore joint congruity and minimize further chondral deterioration. However, chondrocyte implantation techniques and osteochondral grafts are technically challenging in the hip because of its constrained nature, and many cell-based therapies have shown suboptimal results near the chondrolabral junction because of the increased shear forces at the peripheral acetabulum and increased stress at the weight-bearing region of the joint. By using BMAC to augment labral repairs and coat chondrolabral junction breakdown, we are able to introduce mesenchymal stem cells to peripheral acetabular tissue with little to no drawbacks, while avoiding donor-site morbidity, open procedures, and multiple surgeries. The purpose of this Technical Note is to describe a reproducible method for harvesting, processing, and applying BMAC to the chondrolabral surface of the hip during hip arthroscopy without the need for donor-site morbidity or increased labral repair time.

We describe an arthroscopic technique for the treatment of labral pathology and femoroacetabular impingement that provides excellent access to the central and peripheral compartments while preserving the biomechanically crucial components of hip joint stability. The hip capsule and the ligaments within it have been shown to be integral to hip biomechanical stability. Other popular techniques such as interportal and T-capsulotomy inherently damage the capsuloligamentous complex of the hip and can be associated with postoperative gross instability, micro-instability, heterotopic ossification, and seroma. Capsular closure may mitigate some of these effects but has been associated with capsular insufficiency and requires postoperative restrictions that can be prolonged. Our surgical technique focuses on careful portal placement, replacement when necessary, use of a switching stick to maximize peripheral compartment visualization, and joint access in the most minimally invasive manner while avoiding complications associated with extended capsulotomy. The objective of this Technical Note is to describe a technique by which full access to the joint can be obtained while not disrupting the biomechanics of the joint capsule.

The prevalence of hip arthroscopy has increased exponentially with the advent of arthroscopic labral repair techniques for femoroacetabular impingement. The goal of arthroscopic labral repair is to re-create the anatomic suction seal of the labrum against the femoral head. This important anatomic relationship has been demonstrated in several biomechanical studies. Performing the acetabular recession and evaluating the congruity of labral repairs during surgery is difficult with the application of traction distracting the femoral head from the chondrolabral junction. Additionally, prolonged traction risks nerve injury during hip arthroscopy. The purpose of this technique article is to describe a method of using traction only for central compartment work, and releasing the traction to allow the femoral head to reduce the labrum to its anatomic position for acetabular recession, anchor placement, and suture fixation. In this manner, the presented technique prevents an “out-of-round” or everted repair. This technique re-creates the native anatomy and biomechanics of the hip after acetabular recession and labral repair while decreasing traction time.

Adult acquired flatfoot deformity (AAFD), formerly known as posterior tibial tendon (PTT) dysfunction, is one of the most common problems of the foot and ankle. It was first described as tendon failure but has since been revealed as ligamentous failure in addition. AAFD is a spectrum of deformities that ranges from tenosynovitis (stage I) to AAFD (stages II-IV). Regarding mild stage I and stage II disease, it was once standard to perform an open synovectomy completely removing the inflamed synovium; this procedure required a large 6-cm medial ankle incision. Postoperative management included plaster cast immobilization for 3 weeks, followed by a boot with controlled ankle movement for another 3 weeks. Now, the standard is shifting to PTT endoscopy, which has proved to be an efficient way to treat tenosynovitis in stage I and II AAFD with a shorter postoperative period. Using this technique, we can achieve 360° visualization of the PTT within the tendon sheath, allowing for a complete exploration and debridement. We hope that by using this video description, practitioners could avoid the increased morbidity associated with open procedures, as well as help patients return to activity sooner after surgery.

The acetabular labrum plays an important role in hip joint stability and articular cartilage maintenance. As such, reconstitution of the labral complex is ideal. In cases in which the labrum is too degenerative to allow adequate reconstruction with current repair techniques, a capsular augmentation is a novel technique that can be used to restore the labral structure. Use of capsular augmentation enables preservation of the donor-tissue blood supply with local tissue transfer, without adding significant complexity to the procedure or significant donor-site morbidity.

Iatrogenic injury is a known complication of initial portal placement during hip arthroscopy. The rate of labral puncture or damage to the articular surfaces with arthroscopic instruments is variable and may be associated with operator inexperience or complex anatomy. In addition, the amount of traction applied to achieve joint distraction may unnecessarily place patients at risk of neurapraxia. The purpose of this article is to describe the “femoral head drop” technique as a method to increase safe access to the central compartment and minimize the amount of traction needed to do so, especially in patients with challenging bony anatomy. This technique uses the application of intra-articular saline solution to cause inferior migration of the femoral head. Intra-articular fluid distension, or the femoral head drop technique, is simple, safe, and reproducible, making it appropriate for hip arthroscopists at any level of experience.

Traditional techniques for acetabular osteoplasty in femoral acetabular impingement have required surgical detachment of the labrum at the chondrolabral junction. Such approaches compromise labral blood flow and contribute to a limited ability for healing at the chondrolabral junction. In this technical note and accompanying video, we present a technique for preservation of the chondrolabral junction during labral repair and acetabular osteoplasty. We elevate the chondrolabral complex subperiosteally off the acetabular rim, and the acetabular shelf is then contoured under fluoroscopic guidance. The labrum is then repaired and reconstituted to a new anatomic footprint. We find this technique to be advantageous because it preserves the blood flow to the labrum, thereby maximizing healing potential. Outcome studies are warranted to further elucidate the functional and outcome benefits of this surgical technique.

Semiconductor microcavities offer unique systems in which to investigate the physics of weakly interacting bosons. Their elementary excitations, polaritons--mixtures of excitons and photons--can accumulate in macroscopically degenerate states to form various types of condensate in a wide range of experimental configurations, under either incoherent (1,2) or coherent (3,4) excitation. Condensates of polaritons have been put forward as candidates for superfluiditys (5,6), and the formation of vortices(7) as well as elementary excitations with linear dispersion' are actively sought as evidence to support this. Here, using a coherent excitation triggered by a short optical pulse, we have created and set in motion a macroscopically degenerate state of polaritons that can be made to collide with a variety of defects present in the microcavity. Our experiments show striking manifestations of a coherent light-matter packet, travelling at high speed (of the order of one per cent of the speed of light) and displaying collective dynamics consistent with superfluidity, although one of a highly unusual character as it involves an out-of-equilibrium dissipative system. Our main results are the observation of a linear polariton dispersion accompanied by diffusionless motion; flow without resistance when crossing an obstacle; suppression of Rayleigh scattering; and splitting into two fluids when the size of the obstacle is comparable to the size of the wave packet. This work opens the way to the investigation of new phenomenology of out-of-equilibrium condensates., Below a critical temperature, bosons of a sufficiently high number density undergo Bose-Einstein condensation (BEC). Under this condition, the particles collapse into a macroscopic condensate with a common phase, showing [...]

A series of thermoplastic polyurethane elastomers based on polycarbonate diol, 4,4'-diphenylmethane diisocyanate and 1,4-butanediol was synthesized in bulk by two-step polymerization varying polycarbonate diol soft segment molecular weight and chemical structure, and also hard segment content, and their effects on the thermal and mechanical properties were investigated. Dynamic mechanical analysis termogravimetric analysis, differential scanning calorimetry, Fourier transform infrared-attenuated total reflection spectroscopy and mechanical tests were employed to characterize the polyurethanes. Thermal and mechanical properties are discussed from the viewpoint of micro-phase domain separation of hard and soft segments. On one hand, an increase in soft segment length, and on the other hand an increase in the hard segment content, i.e., hard segment molecular weight, was accompanied by an increase in the microphase separation degree, hard domain order and crystallinity, and stiffness. In phase separated systems more developed reinforcing hard domain structure is observed. These hard segment structures, in addition to the elastic nature of soft segment, provide enough physical crosslink sites to have elastomeric behavior. POLYM. ENG. SCI., 48:297-306, 2008. © 2007 Society of Plastics Engineers, INTRODUCTION Thermoplastic polyurethane elastomers are versatile materials that behave as cross-linked elastomers at room temperature but, unlike conventional elastomers, they can be processed, shaped, and formed upon heating via numerous [...]

Performance and aging tests have been done to characterize Gas Electron Multipliers (GEMs), including further design improvements such as a thicker GEM and a closed GEM. Since the effective GEM gain is typically smaller than the absolute GEM gain, due to trapping of avalanche electrons at the bottom GEM electrode, we performed field simulations and measurements for better understanding, and discuss methods to eliminate this effect. Other performance parameters of the GEMs are also presented, including absolute GEM gain, short-term and long-term gain stabilities.

A study was done on the relationships of biological and taxonomic characteristics to chemically mediated bioactivity in Mediterranean littoral sponges. It was shown that antiviral and antifungal characteristics were dependent on taxonomic characteristics especially in Axinellida. Antiviral activity is influenced by growth habit while all other types of biological activity were dependent on sponge skeletal features.