A novel technique for modified all-inside repair of bucket-handle meniscus tears using standard arthroscopic portals.

BACKGROUND: Bucket-handle meniscus tears (BHMT) are often displaced and unstable. The inside-out technique of repairing such tears is currently the gold standard. All-inside repair with meniscal fixators is getting increasingly popular. Shortcomings of the inside-out technique include neurovascular complications, especially saphenous nerve palsy, and retention of a non-resorbable suture which can result in discomfort to patient, granuloma formation, and a foci of infection. Hence, the purpose of this project was to innovate a novel all-inside technique to precisely reduce and fix BHMT while avoiding neurovascular complications and retention of a non-resorbable suture. METHODS: Routine arthroscopic portals were created on a patient's left knee with a displaced BHMT. Through the anteromedial portal, a conjoint pseudo double lumen cannula was inserted. Two limbs of a reduction suture were passed through the cannula, one over the "femoral" surface of the meniscus, one over the "tibial" surface of the meniscus anterior to the biceps femoris tendon, with the knee flexed at 20° to avoid injury to the saphenous nerve. Suture limbs were passed out percutaneously and tensioned. RESULTS: Anatomic reduction was ensured under arthroscopic visualization with ease. All inside repair was performed using the vertical mattress suture configuration. Reduction sutures were subsequently removed by cutting flush to the skin and pulling on one suture limb. The patient was back to full activities with minimal discomfort 8 months post-operatively. CONCLUSION: The technique described is superior to existing techniques for the following reasons: (1) Reduction of the displaced meniscal tear is "extra-meniscal," avoiding further trauma to a damaged meniscus. (2) Tensioning of the two suture limbs created promotes better control of reduction through tensioning. (3) Risk of discomfort, infection, and neurovascular damage caused by a retained suture is reduced. (4) No additional portals/equipment is required. We encourage this novel technique to be attempted by surgeons.

Patellar tendon re-rupture on the opposite end of the previous site of surgical repair.

We describe a rare case of a patellar tendon "re-rupture" at the opposite end of a previous proximal tendon repair. A 32-year-old male with a history of surgically repaired right proximal patellar tendon rupture presented with an acute non-traumatic right knee pain and instability during sports. Magnetic resonance imaging confirmed a complete rupture of his distal patellar tendon at the tibial tuberosity. The patellar tendon was repaired using two 5.5 mm BioCorkscrews (Arthrex) inserted into the tibial tuberosity; the tendon was stitched with the No. 2 fiberwires using Krackow technique. As the patellar tendon was degenerative, the repair was augmented with a semitendinosus tendon harvested using an open tendon stripper, leaving the distal attachment intact. At 2.6 years followup he had mild anterior knee pain, range of motion 0-130° and was able to squat. MRI scan done at followup revealed good healing of repaired patellar tendon.

Super-Enhancers and Broad H3K4me3 Domains Form Complex Gene Regulatory Circuits Involving Chromatin Interactions.

Stretched histone regions, such as super-enhancers and broad H3K4me3 domains, are associated with maintenance of cell identity and cancer. We connected super-enhancers and broad H3K4me3 domains in the K562 chronic myelogenous leukemia cell line as well as the MCF-7 breast cancer cell line with chromatin interactions. Super-enhancers and broad H3K4me3 domains showed higher association with chromatin interactions than their typical counterparts. Interestingly, we identified a subset of super-enhancers that overlap with broad H3K4me3 domains and show high association with cancer-associated genes including tumor suppressor genes. Besides cell lines, we could observe chromatin interactions by a Chromosome Conformation Capture (3C)-based method, in primary human samples. Several chromatin interactions involving super-enhancers and broad H3K4me3 domains are constitutive and can be found in both cancer and normal samples. Taken together, these results reveal a new layer of complexity in gene regulation by super-enhancers and broad H3K4me3 domains.