Clinical trial NCT01046747: Pre-drilling or Self Drilling External Fixation Pins
Official title: Pre-drilling Pilot Holes for Self-drilling Schanz Pins: Does it Reduce the Incidence of Pin Tract Infection and Pin Loosening?
Study type: INTERVENTIONAL
Overall status: UNKNOWN
Phase: NA
Conditions: Fracture
Dislocation
Keywords: external fixation
pin tract infection
self drilling
Lead sponsor: Temple University
Sponsor class: OTHER
First posted: 2010-01-12
Enrollment: 100
Sex: ALL
Minimum age (years): 18
Maximum age (years): 89
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: SINGLE_GROUP
Primary purpose: TREATMENT

Brief summary: Hypothesis

There is no difference in the incidence of pin tract infection and pin loosening in case of lower extremity external fixators when self-drilling schanz pins are used with or without pre-drilling.

Primary Objective

The primary objective is to determine whether pre-drilling holes for external fixation pin insertion is superior to not pre-drilling holes for external fixation pin insertion in regards to the incidence of pin tract infection and pin loosening.

Secondary Objective

If any difference is found between the two techniques then, we will quantify and qualify those differences. The incidence of pin site infection and pin loosening in general will be determined and will also be stratified for site and size of pin. An attempt to identify risk factors for pin site infection will be made by observing the effect of secondary prognostic factors like mode of injury, diabetes, smoking, compartment syndrome, peripheral vascular disease, neurovascular injury. Interobserver reliability of the grading system for pin infection will also be determined.

Detailed description: Background

The application of external fixation is a commonly performed emergency procedure in orthopaedics for temporary stabilization as well as definitive treatment of fractures. External fixation requires that metal pins be placed into the bone on either side of the fracture. The pins are then connected to an external frame, thus stabilizing the fracture. There is debate over the optimal technique for the insertion of these pins in regards to the need to pre-drill a pilot hole prior to pin insertion.

The technology behind external fixation has evolved greatly over the past thirty years. The original external fixation pins, "Shanz pins," were essentially metal rods with threads and a trocar point. A pilot hole was needed because these pins did not have the capability to create their own hole or path in the bone. Recent advances have lead to the creation of self-drilling/self-tapping pins, which have decreased the number of steps necessary to place the pins and thereby decreased operative time. The external fixators are usually placed as a temporary measure to allow for improvement of soft tissue condition before definitive open reduction and internal fixation. Since many external fixation devices are placed in patients who are critically ill, decreasing operative time is very important.

While saving operative time is essential it is also important that the device serves its purpose without leading to complications in the short term. The major complications related to external fixation are pin site infection and pin loosening. The literature is clear that high temperatures created during pin insertion leads to bone necrosis surrounding the pin, increased infection, and increased rates of loosening. It is unclear if the new generation self-drilling pins create the same amount of necrosis as the older generation of pins. Lab studies have shown increased temperatures with direct drilling with these pins as compared to pin insertion after drilling pilot holes with dedicated drill bits. It is unclear if this increased temperature results in increased rate of loosening or pin site infection in clinical practice.

A thorough literature search has revealed no randomized controlled studies to support the use of these pins without drilling pilot holes before insertion. The current standard of care is undefined and left to surgeon preference. Our study aims to provide guidelines for schanz pin insertion for external fixator application, which may help to reduce the number of pin tract infections suffered by patients and improve outcomes.

Study Design and Treatment Plan

This will be a prospective, randomized, within-subject, single-blind trial to be conducted at Temple University Hospital. Patients who are determined to require an external fixation procedure of the lower extremities due to fracture or dislocation will be considered for enrollment according to the above inclusion criteria. Standard of care for treatment of their fractures will be provided. Once patients have provided informed consent for enrollment in the study, their pins will be randomized in a paired design according to a computer generated randomization schedule. There will be two types of pins, pre-drilled and non pre-drilled. A standard external fixation device requires two pins on each side of the fracture. Each pair of pins will have one each of pre-drilled and not pre-drilled pins, according to the randomization schedule. Therefore, each patient will have two pre-drilled pins and two pins inserted without pre-drilling. Some surgeons may prefer three pins on each side of the fracture/dislocation that is to be immobilized. We will have a randomization protocol for these situations as well.

The computer generated randomization algorithm will be placed in a secure location in sealed opaque envelopes. The operating surgeon will open the envelope prior to pin insertion and follow the randomization schedule as prescribed in the envelope.

A standard technique will be followed. IV antibiotics will be administered within 60 minutes of the starting skin incision. Pin insertion will be done by standard techniques. This involves a 1 cm incision, and blunt dissection. 4.0 mm (calcaneal or metatarsal), 5.0 mm (tibia) or 6.0 mm (femur) pins will be inserted by one of two techniques: (1) self drilling pins are inserted with a power drill directly into the bone; (2) a standard twist drill bit is utilized with a power drill to create a pilot hole, followed by insertion of the self-drilling pin by power drill.

Soft tissue relaxation incisions are made according to standard technique after external fixation assembly, as needed. The pin care protocol will consist of daily pin site cleaning using dilute hydrogen peroxide and dry dressings. Patients with suspected pin site infection will be treated with Keflex 500mg po q 6hr. Patients with an allergy to Keflex will receive Clindamycin 300mg po q 6hr.

Eligibility criteria: Inclusion Criteria:

1. Age 18-89
2. Fluency in spoken/ written English/ Spanish (consent form in Spanish will be needed)
3. Lower extremity fracture/ dislocation treated with an external fixator

Exclusion Criteria:

1. Prisoners
2. Patients unable to give informed consent
3. Patients who require that pins be placed without skin coverage at the pin site
4. Patients receiving Ilizarov or other circular external fixators with transfixing wires.

Primary outcomes:
measure: pin tract infection
timeFrame: until pins are removed
Secondary outcomes:
Other outcomes:
Locations:
city: Philadelphia
country: United States
facility: Temple University Hospital
state: Pennsylvania
Study officials:
References:
citation: Abouzgia MB, Symington JM. Effect of drill speed on bone temperature. Int J Oral Maxillofac Surg. 1996 Oct;25(5):394-9. doi: 10.1016/s0901-5027(06)80040-8.
citation: Antoci V, Ono CM, Antoci V Jr, Raney EM. Pin-tract infection during limb lengthening using external fixation. Am J Orthop (Belle Mead NJ). 2008 Sep;37(9):E150-4.
citation: Bachus KN, Rondina MT, Hutchinson DT. The effects of drilling force on cortical temperatures and their duration: an in vitro study. Med Eng Phys. 2000 Dec;22(10):685-91. doi: 10.1016/s1350-4533(01)00016-9.
citation: Bonfield W, Li CH. The temperature dependence of the deformation of bone. J Biomech. 1968 Dec;1(4):323-9. doi: 10.1016/0021-9290(68)90026-2. No abstract available.
citation: Moroni A, Faldini C, Marchetti S, Manca M, Consoli V, Giannini S. Improvement of the bone-pin interface strength in osteoporotic bone with use of hydroxyapatite-coated tapered external-fixation pins. A prospective, randomized clinical study of wrist fractures. J Bone Joint Surg Am. 2001 May;83(5):717-21. doi: 10.2106/00004623-200105000-00010.
citation: Seitz WH Jr, Froimson AI, Brooks DB, Postak P, Polando G, Greenwald AS. External fixator pin insertion techniques: biomechanical analysis and clinical relevance. J Hand Surg Am. 1991 May;16(3):560-3. doi: 10.1016/0363-5023(91)90033-8.
citation: Ziran BH, Smith WR, Anglen JO, Tornetta P 3rd. External fixation: how to make it work. J Bone Joint Surg Am. 2007 Jul;89(7):1620-32. doi: 10.2106/JBJS.G.00425. No abstract available.