Functional Outcome and MRI of Muscle Damage Following Nailing Procedure in Femur (Thigh) Fractures Using Different Entry Points
Condition: Femoral Shaft Fracture
MeSH terms: Fractures, Bone
Study type: Interventional

Summary: 
      Study focus is femoral shaft (thigh bone) fractures (break) that require surgical treatment
      under anaesthetic to stabilize the femur fracture. This is usually done by placing a metal
      nail and screws inside the femur (thigh) bone.

      This study has been designed to allow us to learn more about the effect of using a different
      starting point to insert the nail into the body in order to access the fracture and fix it.
      This question is important because to date, all entry points currently used do result in some
      muscle damage. In order to minimize this damage a lateral (side) entry nail has been
      developed and is currently in use at many centres. This nail is new but, the lateral entry
      technique for these types of fractures has been used extensively in the past, and this nail
      has been developed in order to better accommodate the technique.

      It is believed that entering laterally instead of going deeper into the tissue to access the
      bone to fix it is going to result in less muscle damage which in turn will improve functional
      outcome.
    

Detailed description: 
      Background:

      This study has been designed to prospectively evaluate functional outcome and MR imaging of
      abductor damage following antegrade femoral nailing with different entry points

      Recent developments in IM nailing of the femur have favoured the use of the greater
      trochanter as an entry site as opposed to using the "classical" piriformis fossa. With either
      technique, a persistent problem appears however to be the damage caused to muscle tissue
      during preparation of the femur and insertion of the nail. The recent development of femoral
      nails with an entry point lateral to both these sites offers the potential advantage of
      avoiding abductor muscle damage.

      In several cadaver studies, authors state that a trochanteric entry point causes more damage
      than a piriformis entry, and that an even more lateral entry point causes even less damage to
      the abductor muscles compared to the classical piriformis fossa entry site. There is however,
      no prospective clinical study has specifically evaluated the condition of the abductor tendon
      and the amount of muscle damage after antegrade nailing in the treatment of femoral shaft
      fractures. The few clinical studies that have attempted to examine the functional outcome in
      patients undergoing IM nailing of femoral fractures have used general measurement tools
      (general functional clinical assessment, gross evaluation of gait) which do not reflect the
      state of the art at this time and which do not specifically assess gluteal muscle condition.
      To date, no published study has evaluated the integrity of the gluteus tendon, the damage to
      the surrounding tissues, and the functional outcome using validated scores. Moreover, no
      study has compared the "traditional" entry points to a lateral entry nail with this level of
      precision.

      The standard of care for the treatment of femoral shaft fractures is the insertion of an
      intramedullary nail through the piriformis fossa. Following insertion of femoral IM nails, a
      number of studies have demonstrated excellent clinical and radiographic results with
      relatively few complications such as nonunion, malunion, or infection. Intraoperative
      difficulties with respect to rapid identification of the appropriate starting point have
      prompted the development of nails that use the greater trochanter as an entry site as opposed
      to using the "classical" piriformis fossa.

      As stated earlier, with either technique, a persistent problem appears however to be the
      damage caused to muscle tissue during preparation of the femur and insertion of the nail. The
      recent development of femoral nails with an entry point lateral to both these sites offers
      the theoretical advantage of avoiding abductor muscle damage. There is so far a lack of
      prospective randomized trials which demonstrate radiological and clinical parameters of the
      different entry points.

      Objective To determine the abductor tendon and muscle damage with MR-imaging according to the
      entry point of the femoral nail. Additionally, objective hip muscle function, general health
      status and functional outcome will be assessed using validated instruments.

      We aim to correlate muscle damage due to the different entry points and correlate with the
      functional outcome. Further, to quantify the differences (advantages) of different IM nailing
      techniques of the femur, with respect to effect on the abductor musculature, muscle testing
      and gait, and patient-based functional outcome, to guide surgeons' decisions and future
      research.

      Recent Related Work In a recently published report by Ricci et al. the use of the
      trochanteric entry point was associated with a low complication rate and good clinical
      results including the assessment of a gait video. In this admittedly small prospective study
      the superiority of either the trochanteric or the piriformis fossa entry point nail could not
      be established. Although gait was evaluated video (in 30% of the study population), this was
      limited to a subjective assessment of the presence of a Trendelenberg gait (absent, slight or
      present). There was no statement about the muscle status, and functional outcome assessment
      was limited to a Harris Hip Score.

      Abductor tendon condition and muscle damage has previously been assessed with MR-imaging by
      the group of Pfirrmann et al. in patients with total hip arthroplasty through a transgluteal
      approach. This study showed a high correlation between damage and clinical outcome.

      The co-applicant's research group has previously carried out many clinical studies including
      its part in a multi-centre randomized trial in femur fractures. It also specifically has
      carried out a functional assessment of patients following femur fractures which included:
      objective muscle testing of isokinetic force using a KinCom® dynamometer, formal gait lab
      analysis using an eight camera real-time motion capture system in conjunction with a
      force-plate walking platform, and as part of the same study, the administration of validated
      self-assessment outcome questionnaires.

      So far no prospective randomized trial has investigated, as we have planned to do, the
      radiological (MR), functional, and clinical outcome after insertion of a femoral nail through
      two different entry points.

      Method Patients will be assigned randomly (via computer generated randomization) to one of
      two groups. The two groups will undergo standard treatment of IM nailing for the femoral
      shaft fracture differing only in entry point of the nail: piriformis fossa entry point versus
      lateral entry point.

      Design Patients between 19 and 60 years of age presenting with an isolated femoral shaft
      fracture that requires IM nailing will be asked to participate in this study. Informed
      consent for participation in the study will be obtained by either a member of the health care
      team or by a research nurse.

      Consenting patients who meet the inclusion criteria will be randomized to either piriformis
      fossa or lateral entry femoral nailing. Preoperative, Intraoperative, and follow-up data will
      be obtained. Data will detail clinical assessment, MRI results, objective muscle testing, and
      gait analysis.

      Power analysis In a published report from Pfirrmann et al. distinct conclusions could be made
      in a collective of 54 patients. We plan to recruit 60 patients (30 per group) with a
      projected drop-out rate of 10%. As this is a pilot study, without previous reference, a
      similarity in expected findings and required sample size must be inferred. Cases will be
      randomized using a web-based allocation tool.

      Outcome Variables:

      Variables for collection and analysis are:

        1. Preoperative:

           i) Demographics ii) ISS (Injury Severity Score) iii) AO Fracture Classification

        2. Intraoperative:

           i) Elapsed time from injury to operative treatment ii) Fluoroscopy time iii) Incision
           length iv) Blood loss

        3. Postoperative:

           i) VAS pain scores ii) Morphine requirements q 24hrs iii) Change in hemoglobin q 24hrs
           iv) Hospital Length of Stay v) Clinical and Radiological follow-up at 3, 6, 9, and 12
           months vi) MRI at 12 months vii) Self-administered validated outcome tools at 6 and 12
           months (SF-36, SMFA, Harris Hip Score, Merle d'Aubigne score) although last two are not
           validated they would allow for comparison with widely published scores in established
           literature

           Study Specific Measures:

           Postoperative follow-up:

           All patients will be reviewed clinically in the fracture clinic at two, six, twelve
           weeks, and six and twelve months postoperatively. Study data will be acquired at the six
           and 12 month appointments.

           Clinical assessment:

           Bilateral measurements will be recorded so that the results from the unaffected limb are
           used as a control for the injured limb. Both the raw data and the side to side
           differences will be used in the analysis. Physical examination to document any limb
           length discrepancy, Trendelenberg sign, rotational malalignment, and the ranges of
           motion of the hip and knee.

           Questionnaires:

           A study specific questionnaire will be administered to determine the extent and location
           of any persistent pain in the affected limb, ability to return to their usual occupation
           and recreational activities.

           Functional outcome scores (SF-36, SMFA, Harris Hip Score, Merle d'Aubigne score) will be
           collected at 6 and 12 months. All of these outcomes tools are widely referenced in the
           literature and can be used for comparison purposes.

           MR Imaging:

           An MRI will be administered at 12 months and will include evaluation of abductor tendon
           defects, diameter, signal intensity, ossification, and bursal fluid collections. The
           abductor muscles will be evaluated by MRI for fatty atrophy.

           Muscle strength testing and gait analysis:

           Muscle strength testing will take place at 12 months and will utilize the KinCom
           Dynamometer (a widely used, standard research protocol and specifically-designed
           instrument for use in muscle strength testing) to evaluate muscle strength: Peak
           isokinetic force measurement: maximum strength (nm/kg), and work (J/min) of hip
           abductors, hip extensors, and knee extensors.

           Gait analysis will take place at 12 months and will employ a standard eight camera
           real-time motion capture system in conjunction with a force-plate walking platform to
           collect and evaluate pelvic obliquity, hip abductor movement, single leg support time,
           and step length.

           Data Analysis:

           The side-to-side differences will be summarized and compared across treatment groups.
           Additionally, aggregated raw data by treatment group will be summarized and compared,
           using t-test for the comparison of continuous variables' means, and Chi-square for
           categorical data.
    

Intervention name(s): Femoral Nailing with Different Entry Points
Intervention type(s): Device
Intervention description(s): See Detailed Description.
Allocation: Randomized
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Femur; Fracture; Antegrade; Nailing; Shaft; Abductor