Functional Outcome of Isolated Posterior Cruciate Ligament Avulsion Fractures Treated by Open Reduction and Internal Fixation

Isolated Posterior cruciate ligament (PCL) avulsion fractures are uncommon, but are complicated intra-articular fractures.1 In India due to high prevalence of motorcycle transportation, the cause of PCL avulsion fractures was predominantly motorcycle accidents, though sports accidents still remain the most common cause in world over. These injuries are quite often missed in the emergency department and are often neglected. In the long run they cause severe functional disability of the knee joint. There is no consensus concerning the optimal surgical treatment approach for these injuries. Hence, we aimed to study the functional and clinical outcome of isolated PCL avulsion fractures with open reduction and internal fixation.METHODSThis is a prospective study of 28 cases of isolated PCL tibial avulsion fractures, in patients aged between 22-38 years during the period 2014 - 2018 in our hospital. All were treated with open reduction and internal fixation with 4 mm cannulated cancellous screw and washer. Postoperatively, patient leg was immobilized in posterior POP slab for 2 weeks, allowing toe touch weight bearing. All patients were regularly followed-up at 2, 4, 6, 8, 10, and 12 weeks. The functional outcome is assessed by Lyndholm scoring at the end of 12 weeks.RESULTS98% of the cases have shown excellent results with good range of movement in the knee without pain and without knee instability. The other 2% of cases had mild knee arthrofibrosis and pain.CONCLUSIONSPCL Avulsion fractures are rarity but yet need to be managed surgically. Open reduction and internal fixation by Burks and Schaffer approach has resulted in excellent results and good functional outcome.

Inactivation of the NHEJ Activity of DNA-PKcs Prevents Fanconi Anemia Pre-Leukemic HSC Expansion

Fanconi anemia (FA) is a genetic disorder characterized by bone marrow failure and high risk of cancer particularly leukemia. Here we show that inactivation of the non-homologous end-joining (NHEJ) activity of DNA-PKcs prevented DNA damage-induced expansion of FA pre-leukemic hematopoietic stem cells (HSCs). Furthermore, we performed serial BM transplantation to demonstrate that the DNA damage-induced expanded FA HSC compartment contained pre-leukemic stem cells that required the NHEJ activity of DNA-PKcs to induce leukemia in the secondary recipients. These results suggest that NHEJ may collaborate with FA deficiency to promote DNA damage-induced expansion of pre-leukemic HSCs.