Abstract:

BACKGROUND: The most important influence caused by patellar fracture is the breakage of knee extension apparatus continuity and potential uncoordination of patellofemoral joint. The aim of patellar fracture surgery is to restore the smoothness of patellar articular surface and to maintain the continuity of knee extension apparatus, to provide stable effective fixation, so as to do early functional exercises.
OBJECTIVE: To evaluate the clinical effectiveness of a fixation technique for patellar fractures using QWIX combined with Kirschner wire and wire.  
METHODS: From September 2011 to September 2012, 30 patients with patellar fractures were treated using QWIX screws combined with Kirschner wire and wire in the First Affiliated Hospital of Chongqing Medical University, China. There were 17 males and 13 females, at the age of 47.7 years on average. In accordance with the situation of comminuted fracture and the degree of displacement, QWIX screws or QWIX screws + tension band wire or QWIX screws + Kirschner wire + tension band wire were used for fixation. Active and passive knee motion exercises began at 1 day after surgery, without any external fixation. At 6 weeks, 3, 6, 12 months, and 1  year after surgery, the patients were followed up in out-patient clinic to identify fracture healing and to make sure whether complications appeared or not. The range of flexion and extension of bilateral knee was measured. The knee function of the affected side was evaluated using Bostman score at 1 year postoperatively.
RESULTS AND CONCLUSION: All patients were followed up for 12 to 24 months. 24 cases were healed within 3 months after surgery, and 6 cases were healed within 4 months after surgery, with an average healing time of 3.2 months. With time prolonged, the range of flexion and extension of bilateral knee gradually increased. The knee function of patients recovered to the level before injury at 1 year after surgery. During follow-up, one patient experienced knee pain due to Kirschner wire loosening. No infection, knee pain, fixation failure, or flexion dysfunction occurred in the remaining patients. In accordance with Bostman score, there were excellent in 27 cases, good in 3 cases, and poor in 0 case, with an excellent and good rate of 100% at 1 year following surgery. Results data suggested that QWIX screws combined with Kirschner wire and wire fixation in repair of patellar fracture have some advantages such as continuous dynamic and static pressure at the broken ends of the bones, early flexion and extension exercises, and reducing the fixation-related complications. It is an effective method to repair patellar fracture.

Key words: patella, fractures, bone, internal fixators, follow-up studies