Tibial IMN Vs. Tibial Micromotion IMN

Overview

Our null hypothesis is that micromotion tibial intramedullary fixation (IMFN) does not impact union or complication rates when compared to standard of care treatment with non-micromotion tibial nail fixation. There are no current or past randomized controlled trials comparing these fixation techniques to one another. There is good data supporting both the use of intramedullary fixation for tibial fractures alone, and in high-risk patient populations (open fractures, GSW tibial fractures). However, the effectiveness of these methods with respect to each other has never been investigated. The knowledge gained will allow us to potentially influence and adapt protocols to treat this patient population. Additionally, resources available at our institution provide a supportive framework with which to maintain contact with patients after hospital discharge. These key factors will allow us to perform a robust analysis of this population, to include outcomes measures of function and complications. With much of the limited existing literature on tibial nails being in very defined populations, without a strong comparison group there is no clear guidance on when the use of a micromotion device is indicated. Our approach to randomize our patients will reduce the bias that exists in the current literature and provide a robust spectrum of injuries to sub analyze and compare. Objectives Primary Objective Compare post-operative union rates in tibial shaft patients treated with 2 types of intramedullary rod fixation devices. Secondary Objective(s) Compare complication rates, patient reported outcomes, range of motion, pain and radiographic/sonographic outcomes in patients treated with tibial nails.

The advent of the intramedullary nail (IMN) has revolutionized the treatment of tibial shaft fractures due to its percutaneous route of insertion, frequent facilitation of immediate weightbearing, and high rate of union. Recent research has revealed that selection of an appropriate IMN diameter is vital for maintaining fracture reduction and preventing complications. Using a larger diameter nail increases construct stability, permits load-sharing, and may lead to higher rates of union. On the other hand, aggressive reaming to permit a larger nail diameter can result in iatrogenic fracture upon insertion or removal. Modern tibial nail designs have remained largely unchanged in the last 20 years with small ergonomic and efficiency changes without large scale improvements in their biomechanical induction of bone healing at the fracture site. Traditionally they include distal locking screws as well as proximal locking screws that are either fixed or dynamic allowing for small but largely irrelevant amounts of motion. Our understanding of bone healing and indirect bone generation includes the concept of micromotion which induces the creation of fibrous followed by bony callus. This concept requires strain levels and adequate micromotion at fracture sites to be biomechanically advantageous. One new tibial nail device recently available in the US and FDA approved for tibial nail fixation hopes to improve the biomechanical and biology environment for tibial healing, the OrthoXel tibial nail system. Unfortunately, there is a paucity of strong clinical data to support it. Additionally, there have been no prospective, randomized studies investigating the used of this nail compared to standard tibial nail designs and no studies have evaluated it in high risk tibial non-union patients.. The primary purpose of this study is to perform a high-quality randomized control trial comparing intramedullary tibial nail fixation with standard design nails compared to a micromotion tibial nail device to evaluate the rates of union and post-operative outcomes. In an evaluation of patient factors, fracture patterns and patient reported outcomes, the investigators will bring clarity to the question of indications for the micromotion tibial nail in standard and high risk patients. To characterize our patient population, the investigators will evaluate type of injury (closed, open, gunshot wound), fracture morphology (OTA classification), patient risk factors (age, isolated vs. poly-trauma, Comorbidities, smoking, and Vit D levels) and surgical outcomes (blood loss, surgical time, construct stability). In addition to objective radiographic, ultrasonographic and physical exam outcomes, the investigators will collect patient reported outcomes in the form of PROMIS CAT and VAS scores. Given the existing limitations in the literature, there is no guidance on indications for use of micromotion tibial nail fixation (MMIMNF) compared to standard intramedullary nail fixation (IMNF). By taking an approach that will be prospective and randomized, while assessing all known risk factors, the investigators expect our results will guide surgical treatment decisions around the use of these devices and in which populations they may be most useful. . The proposed trial will be a parallel-group, superiority trial with equal randomization enrolling 242 tibial nail patients. Patients will be categorized into 2 cohorts: IMNF fixation(cohort 1), and MicroMotion Intramedullary tibial Nail fixation (cohort 2). The primary outcome will be nonunion. Secondary outcomes will include: overall complications (as a composite result (Infection ((deep and superficial)), revision surgery rate, removal of metalwork, non-union, malunion, amputation and death). Patient-Reported Outcomes Measurement Information System Physical Function Computerized Adaptive Testing (PROMIS PT CAT) scores, range of motion (ROM), pain, radiographic outcomes, time to bridging callus based on mRUST (\>11) on Xray, time to single leg stance, and degree of callus seen on ultrasound at 6 \& 12 weeks.