Static Helical Screw Locking of Pertrochanteric Femur Fractures Using the TFN-A (TFN-A)

Static Helical Screw Locking of Pertrochanteric Femur Fractures Using the TFN-Advanced Proximal Femoral Nailing System - A Randomized Trial

The study will investigate the shortening and collapse of pertrochanteric fractures following surgical management with the TFN-Advanced nailing system. The focus will be on comparing radiographic assessments of nails which have been statically locked versus dynamically locked. This is a randomized control study with the initial invention being randomized to either statically locking or dynamically locking. For a two-month period, all eligible patients will receive the randomized allocated treatment, then treatment will switch to the alternate treatment for the next two months and will continue to alternate treatments for two-month periods until study enrollment has completed.

Hip fractures are common injuries in the elderly population that result in significant morbidity and mortality and a significant burden on health care systems. Hip fractures can be treated with arthroplasty or with internal fixation, depending on the fracture pattern. Cephalomedullary nailing (CMN) has become one of the established treatments for intertrochanteric hip fractures with a wide variety of implant designs from many different companies. The TFN-ADVANCED™ Proximal femoral nailing system (TFN-A) is a novel implant for treating intertrochanteric and subtrochanteric proximal femur fractures with a paucity of published literature on the performance of this implant. A method to decrease the amount of fracture compression is to use the set screw to lock the helical screw "statically" so it does not slide to the same degree as if the helical screw is placed in the "dynamic" or sliding position. To the knowledge of the investigators, the role of statically locking the helical screw to prevent fracture collapse has not been studied. Statically locking CMN to treat hip fractures has become standard of care at the Royal Columbian Hospital with all the investigating surgeons having adopted this practice in an attempt to prevent significant fracture collapse and neck shortening. Anecdotally, the investigators have not seen significant rates of cephalic helical screw cut-out over the past five years, and believe the investigators' helical screw cut-out rates are lower than what is reported in the literature. The investigators have been using the Gamma Nail (Stryker) to statically lock the helical screw as the previous TFN lacked the ability for static locking. However, with the advent of the TFN-A, the investigators have adopted this implant as their long cephalomedullary nail of choice for fixation of pertrochanteric femur fractures.

Randomized trial design utilizing alternating treatment allocation to assign patients to treatment arms, treatment allocations will last for two months at a time.

Surgeons cannot be blinded to the treatment allocation of the surgical intervention due to having to perform the static or dynamic rotational lock. Participants will be blinded to the form of locking they receive. Research personnel administering the questionnaires and completing the outcome measures will be blinded. Data analyst(s) and the radiographic reviewer(s) will be blinded to the treatment arm.

Using a fracture table, the affected leg will be placed into traction and the patient will be prepped and draped in the usual fashion. The fracture will be provisionally reduced using closed techniques. A 3cm incision will be used to gain access to the intramedullary canal and the nail (either a short nail or long nail, at the discretion of the treating surgeon) will be introduced to the femur. The helical screw will be placed across the fracture and into the femoral head, aiming for a tip-to-apex distance less than 25mm. The compression nut will be used to compress the fracture. The helical screw will be rotationally locked by using the 5mm hex flexible screwdriver by advancing the set screw until it stops completely. The screw will then be turned counterclockwise by a ½ turn.

Using a fracture table, the affected leg will be placed into traction and the patient will be prepped and draped in the usual fashion. The fracture will be provisionally reduced using closed techniques. A 3cm incision will be used to gain access to the intramedullary canal and the nail (either a short nail or long nail, at the discretion of the treating surgeon) will be introduced to the femur. The helical screw will be placed across the fracture and into the femoral head, aiming for a tip-to-apex distance of less than 25mm. The compression nut will be used to compress the fracture. The helical screw will then be statically locked using the 6Nm torque-limiting blue handle with 6mm hex coupling to completely lock the set screw down on the helical screw.

Performed, as per the Synthes technique guide, using the 5mm hex flexible set screwdriver and then loosening the set screw by one-half turn of the screwdriver.

Performed by using the torque-limiting set screwdriver and locking the set screw down onto the helical screw to prevent dynamic sliding of the helical screw within the nail.

The primary objective of this study will be to investigate how statically locking the TFN-A influences shortening or collapse of pertrochanteric fractures by measuring radiographic shortening or collapse of pertrochanteric fractures treated with the TFN-A implant.

Used to assess walking capabilities. The test involves documenting the time taken for participants to rise from a standard arm chair, walk to a line on the floor 3 meters away, turn, return, and sit down again. The test is measured in seconds. The TUG test has been demonstrated to be highly predictive of final functional outcome at two years post-operatively in the hip fracture population.

Participants overall assessment of their pain at rest and with walking over the past week on a 10 cm visual analogue scale. 0=no pain, 10=worst possible pain.

Study patients with chronic conditions to establish an idea of overall health and function. To provide a solution to reduce respondent burden.

A patient and physician-completed instrument that consists of subscales for pain severity, function, absence of deformity and range of motion. Scores range from 0 to 100, with 0 demonstrating worse disability.

Inclusion Criteria: Patients >18 years of age AO/OTA 31-A fractures who the surgeon deems eligible for treatment with a cephalomedullary nail Open and closed fractures Ambulatory prior to injury (with or without walking aides) Native (non-fractured, no implant) contralateral hip Willing and able to sign consent (substitute decision maker) Able and willing to answer patient-reported outcome questionnaires and attend standard-of-care clinical visits Exclusion Criteria: Contralateral hip fracture or hip arthroplasty Fracture not amenable to treatment with a cephalomedullary nail Non-ambulatory patient Fractures >14 days (time of injury to OR) Bilateral pertrochanteric hip fractures Non-unions Pathologic fractures Periprosthetic fractures Patients with spinal injury Incarceration Pregnancy Limited life expectancy due to significant medical co-morbidities or medical contra-indications to surgery Dementia Unable to complete patient-reported outcome measures Likely problems, in the judgement of the investigators, with maintaining follow-up (i.e., patients with no fixed address, report a plan to move out of town, or intellectually challenged patients without adequate family support).

Participant data will be kept confidential. Study findings and de-identified study data will be available to other researchers in the form of a published paper.

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