Undisplaced Femoral Neck Fractures 2 Hansson Pins or 3 Pins Interlocked in Plate (Pinloc) Using RSA

Study Overview
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Brief Summary
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Femoral neck fractures represent about half of the hip fractures and are further divided into displaced and undisplaced fractures. Displaced femoral neck fractures are almost always treated surgically with arthroplasty. However there is an ongoing debate on which implant is superior for undisplaced fractures. A novel implant design (Pinloc) has been developed by Swemac Innovation AB. While the original implant consisted of 2 isolated hook pins, the modified design consists of 3 titanium hook pins interlocked in an aluminum plate. Interlocking is a new principle of implant design and improves fixation and load transfer amongst the pins. The superiority of the modified design is so far only proven preclinically. The role of the Pinloc in clinical use remains unclear. Investigators are planning a randomized controlled trial on undisplaced femoral neck fractures to establish a method for implanting the tantalum markers, to observe the fracture healing process and to further investigate the role of the Pinloc.

Detailed Description
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Femoral neck fractures represent about half of the hip fractures and are further divided into displaced and undisplaced fractures. Displaced femoral neck fractures are almost always treated surgically with arthroplasty. However there is an ongoing debate on which implant is superior for undisplaced fractures. A novel implant design (Pinloc) has been developed by Swemac Innovation AB. While the original implant consisted of 2 isolated hook pins, the modified design consists of 3 titanium hook pins interlocked in an aluminum plate. Interlocking is a new principle of implant design and improves fixation and load transfer amongst the pins. The superiority of the modified design is so far only proven preclinically. The role of the Pinloc in clinical use remains unclear. A series of studies is now planned at Oslo University Hospital in collaboration with Diakonhjemmet Hospital in hope to further clarify this debate. The use of the Pinloc has been introduced in some regions (e.g. Norway, Sweden and Japan). The role of the Pinloc remains unclear and very little has been published on it's use, even though it is believed to be an important contributor of stability to the fixation. Femoral neck fractures are mainly caused by a fall from own height in the elderly. The fractures are most often classified as displaced or not, using the simplified Garden classification. Several other classification systems also exist, but these have not been shown to be of reliable clinical usefulness. The ideal classification system should be easily applicable, reliable, and aid in treatment decision making and prognosis. The treatment of femoral neck fractures comprise perioperative and operative modalities. The perioperative modalities consist among others of medical optimalization preoperatively, early rehabilitation and prevention of new fractures by treating osteoporosis and preventing new falls. The main scope of the current study will, however, be the operative modalities. Surgery for undsiplaced femoral neck fractures is performed mainly with internal fixation on a traction table, using either screws, pins or a sliding hip screw (SHS), available in various designs from different manufacturers. The latest Cochrane review did not conclude on which implant is the superior. Radiostereometry (RSA) is the most precise and accurate method to measure motion in vivo between different segments in orthopaedic research. To do so, radioopaque tantalum markers are implanted into the bone defining different segments. Stereoradiographs are performed over time to detect movement and monitor the healing (or non healing) process. This movement can be calculated both as translations and rotations. They are ideal to describe and compare the stability of fracture systems. RSA has been used successfully in earlier studies on fracture healing. Due to the high accuracy and precision, RSA yield reliable results with relatively small study-groups. Investigators plan to use RSA to measure fracture dislocation and time to healing in our studies. The study will be on the function of the Pinloc and it´s ability to prevent secondary dislocation in undisplaced femoral neck fractures. Investigators will utilize RSA for measurements during follow-up.

Official Title
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Undisplaced Femoral Neck Fractures Treated With 2 Hansson Pins Without Plate or 3 Hansson Pins Interlocked in a Plate (Pinloc) - A Randomized Controlled Trial Using Radiostereometry

Conditions
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Hip Fractures, Femoral Neck Fractures

Intervention / Treatment
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* Device: Pinloc
* Device: 2 Hansson pins


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: undisplaced femoral neck fractures able to walk independently, aids such as crutches or walker allowed able to consent fit for surgery with pins with or without plate Exclusion Criteria: not willing or able to attain follow up previous fracture or surgery with retained metal work in the same hip concomitant disease that will shorten life expectancy (i.e. cancer, COPD)

Ages Eligible for Study
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Minimum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: 2 Hansson pins without plate<br>Patients with undisplaced femoral neck fractures operated with 2 isolated Hansson pins. | Device: 2 Hansson pins<br>* 2 isolated hook pins.(Without plate)<br>* Other names: 2 isolated hook pins.;|
| Active Comparator: 3 Hansson pins interlocked in a plate<br>Patients with undisplaced femoral neck fractures operated with 3 Hansson pins interlocked in plate (Pinloc). | Device: Pinloc<br>* 3 hook pins interlocked in plate.<br>* Other names: 3 hook pins interlocked in plate.;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in fracture displacement during healing measured with radiostereometry | Will be measured by RSA postoperatively, before discharge and after 4, 8, 12, 24 and 52 weeks. Total displacement from first reading to the reading showing maximum displacement is the main outcome. | Up to 52 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Perioperative blood loss |  | 1 week | 
| Time of surgery |  | 1 week | 
| Eq5d | Health Related Quality of Life (Hrqol). | 52 weeks | 
| Eq5d | Hrqol. | 26 weeks | 
| Eq5d | Hrqol. | 12 weeks | 
| Eq5d | Hrqol. | 4 weeks | 
| Change in time to union as measured by RSA (cessation of motion) and radiographs | When RSA shows that no motion has happened between two time points the fracture will be regarded as healed at the former time point. | Will be examined at 4, 12, 26 and 52 weeks | 
| Change in time to union as measured by plain radiographs and clinical findings | Composite endpoint: Healing defined by obliteration of fracture line radiographically and pain free weight bearing (except lateral pain from hardware), when this occurs the fracture will be considered healed. | Will be examined at 4,12, 26 and 52 weeks | 
| Harris Hip Score | Will be examined at 4,12, 26 and 52 weeks | Up to 52 weeks | 
| Postoperative pain (NRS) while in hospital | Pain at mobilization (NRS) at discharge | 1 week | 
| Timed Up and Go test | Tug | 4 weeks | 
| Timed Up and Go test | Tug | 12 weeks | 
| Timed Up and Go test | Tug | 26 weeks | 
| Timed Up and Go test | Tug | 52 weeks | 
| Pain (NRS) | Maximum hip pain during the last week | 4 weeks | 
| Pain (NRS) | Maximum hip pain during the last week | 12 weeks | 
| Pain (NRS) | Maximum hip pain during the last week | 26 weeks | 
| Pain (NRS) | Maximum hip pain during the last week | 52 weeks | 
| Satisfaction with operated hip (NRS) | NRS | 4 weeks | 
| Satisfaction with operated hip (NRS) | NRS | 12 weeks | 
| Satisfaction with operated hip (NRS) | NRS | 26 weeks | 
| Satisfaction with operated hip (NRS) | NRS | 52 weeks | 
| Motion during healing as measured by radiostereometry. | Will be measured by RSA postoperatively, before discharge and after 4, 12, 24 and 52 weeks. | Up to 52 weeks | 
| Motion during healing as measured by plain radiographs. | Will be measured by RSA postoperatively, before discharge and after 4,12, 24 and 52 weeks. | Up to 52 weeks | 
| Reoperation for healing problems | Any additional surgery addressing healing problems or hardware failure | 52 weeks | 
| Mortality | Any reason | 52 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Undisplaced