Bioabsorbable Screw Fixation Provides Good Results With Low Failure Rates at Mid-term Follow-up of Stable Osteochondritis Dissecans Lesions That Do Not Improve With Initial Conservative Treatment.

Purpose: To evaluate the clinical and radiographic outcomes of patients who have undergone bioabsorbable screw fixation for intact, stable grade I and II osteochondritis dissecans (OCD) lesions for which at least 6 months of conservative management has failed. Methods: A retrospective review of prospectively collected data from a single institution was performed to identify patients who underwent internal fixation of stable grade I and II OCD lesions (according to the Guhl classification) between January 2010 and January 2020. Patients were included regardless of the presence of concomitant procedures. The inclusion criteria consisted of (1) primary surgery, (2) failure of at least 6 months of conservative management, (3) the use of a bioabsorbable screw (or screws), and (4) minimum 2-year clinical follow-up. Radiographs were obtained at a minimum of 1 year postoperatively. Patient demographic characteristics, clinical patient-reported outcomes, complications, and failure rates were noted. Results: Twenty-four knees among 23 patients (96% follow-up) were analyzed and followed up for 6.36 ± 3.42 years (range, 2.0-12.7 years). Patients showed statistically significant postoperative improvements in all patient-reported outcomes including the Lysholm score, International Knee Documentation Committee score, and Knee Injury and Osteoarthritis Outcome Score subscales (P < .05). In 3 knees (12%), a reoperation was required due to failure at an average of 3.64 years after the index procedure. No specific complications were attributed to the use of bioabsorbable screws. Patients in whom primary surgical treatment failed did not differ in demographic characteristics, arthroscopic findings, or surgical treatment from those who had successful treatment. Conclusions: Internal fixation of stable grade I and II OCD lesions with bioabsorbable screws produces reliable results with a 12% rate of failure in appropriately indicated patients in whom at least 6 months of conservative management has failed. Clinical outcomes improved significantly during the mid-term follow-up period. Level of Evidence: Level IV, therapeutic case series.

An oviduct glycan increases sperm lifespan by diminishing the production of ubiquinone and reactive oxygen species†.

Sperm storage by females after mating for species-dependent periods is used widely among animals with internal fertilization to allow asynchrony between mating and ovulation. Many mammals store sperm in the lower oviduct where specific glycans on oviduct epithelial cells retain sperm to form a reservoir. Binding to oviduct cells suppresses sperm intracellular Ca2+ and increases sperm longevity. We investigated the mechanisms by which a specific oviduct glycan, 3-O-sulfated Lewis X trisaccharide (suLeX), prolongs the lifespan of porcine sperm. Using targeted metabolomics, we found that binding to suLeX diminishes the abundance of 4-hydroxybenzoic acid, the precursor to ubiquinone (also known as Coenzyme Q), 30 min after addition. Ubiquinone functions as an electron acceptor in the electron transport chain (ETC). 3-O-sulfated Lewis X trisaccharide also suppressed the formation of fumarate. A component of the citric acid cycle, fumarate is synthesized by succinate-coenzyme Q reductase, which employs ubiquinone and is also known as Complex II in the ETC. Consistent with the reduced activity of the ETC, the production of harmful reactive oxygen species (ROS) was diminished. The enhanced sperm lifespan in the oviduct may be because of suppressed ROS production because high ROS concentrations have toxic effects on sperm.

An oviduct glycan increases sperm lifespan by diminishing ubiquinone and production of reactive oxygen species.

Sperm storage by females after mating for species-dependent periods is used widely among animals with internal fertilization to allow asynchrony between mating and ovulation. Many mammals store sperm in the lower oviduct where specific glycans on epithelial cells retain sperm to form a reservoir. Binding to oviduct cells suppresses sperm intracellular Ca 2+ and increases sperm longevity. We investigated the mechanisms by which a specific oviduct glycan, 3-O-sulfated Lewis X trisaccharide (suLe X ), prolongs the lifespan of porcine sperm. Using targeted metabolomics, we report that binding to suLe X diminishes the abundance of the precursor to ubiquinone and suppresses formation of fumarate, a specific citric acid cycle component, diminishing the activity of the electron transport chain and reducing the production of harmful reactive oxygen species (ROS). The enhanced sperm lifespan in the oviduct may be due to suppressed ROS production as many reports have demonstrated toxic effects of high ROS concentrations on sperm.

Osteochondral Allografts: Pearls to Maximize Biologic Healing and Clinical Success.

We present an evidence-based approach to optimize the biologic incorporation of osteochondral allografts: (1) The donor graft is gradually rewarmed to room temperature to reverse the metabolic suppression from cold storage. (2) The graft is harvested while submerged in saline to limit thermal necrosis. (3) Subchondral bone depth is preferred at 4 to 6 mm depth (total plug depth ∼5-8 mm including articular cartilage) to reduce graft immunogenicity and to promote incorporation. (4) The bone is prepared with grooves/beveling to decrease impaction forces, increase access to subchondral deep zones during preparation, and promote graft-host interface healing. (5) High-pressure pulsed lavage is used to reduce antigenicity by removing marrow elements. (6) Pressurized carbon dioxide following pulsed lavage further reduces marrow elements and improves graft porosity for orthobiologic incorporation. (7) Orthobiologic substances (e.g., concentrated bone marrow aspirate) may enhance incorporation on imaging and result in greater osteogenic potential. (8) A suture is placed behind the graft to facilitate removal and repositioning; atraumatic graft insertion without high impaction forces maintains chondrocyte viability. These evidence-based pearls for osteochondral allograft handling optimize metabolic activity, reduce thermal necrosis, reduce antigenicity with removal of marrow elements, enhance biologic potential, and maintain chondrocyte viability to optimize biologic healing and clinical success.