Study of Antibiotic Spacer Design to Treat Infection After Hip Replacement
| Status: | Recruiting |
|---|---|
| Conditions: | Arthritis, Osteoarthritis (OA), Infectious Disease |
| Therapuetic Areas: | Immunology / Infectious Diseases, Rheumatology |
| Healthy: | No |
| Age Range: | 18 - 100 |
| Updated: | 8/30/2018 |
| Start Date: | August 2011 |
| End Date: | August 2020 |
| Contact: | Peter N Chalmers, MD |
| Email: | peter_chalmers@rush.edu |
| Phone: | 3129425000 |
Articulating Versus Static Antibiotic Loaded Spacers for the Treatment of Prosthetic Hip Infection
Infection remains one of the most difficult-to-treat complications of total hip arthroplasty.
The gold standard treatment is two-stage removal of the prosthesis with later replacement of
permanent implants.The first stage consists of removal of the infected arthroplasty
components and the surrounding devitalized tissue, copious pulsed irrigation, and placement
of a temporary antibiotic-impregnated cement spacer. This spacer is typically left in place
six weeks, during which time the patient receives intravenous antibiotics. After the surgeon
feels that the infection has been eradicated, or if a second debridement is required, a
second operative procedure is performed. While the use of an antibiotic spacer is well
accepted, whether the spacer should immobilize the hip (a so-called "static" spacer) or allow
for range of motion (a so-called "articulating" spacer) is controversial. Proponents of
static spacers argue that immobilization of the periarticular soft tissues aids in clearance
of the infection and that these spacers are simpler to fashion intraoperatively. Proponents
of articulating spacers argue that they improve hip function, prevent damage to the
musculature surrounding the hip, allow easier reimplantation, improve hip function, and
prevent dislocation following hip reimplantation. While good results have been described with
both methods, comparative trials have been conflicting as to whether spacer design alters hip
function, operative time, and dislocation rates. Equipoise exists within the literature, and
no randomized clinical trial has been conducted to evaluate this issue.
The purpose of this study is to compare articulating and static antibiotic-impregnated
spacers for the treatment of chronic periprosthetic infection complicating total hip
arthroplasty through a prospective, randomized clinical trial. The goals of this trial are to
determine the effect of spacer design upon eradication of infection, hip function, ease of
reimplantation, and dislocation rates. The investigators hypothesize that articulating
spacers will provide shorter operative times at replantation while improving hip function and
hip dislocation rates following hip reimplantation.
The gold standard treatment is two-stage removal of the prosthesis with later replacement of
permanent implants.The first stage consists of removal of the infected arthroplasty
components and the surrounding devitalized tissue, copious pulsed irrigation, and placement
of a temporary antibiotic-impregnated cement spacer. This spacer is typically left in place
six weeks, during which time the patient receives intravenous antibiotics. After the surgeon
feels that the infection has been eradicated, or if a second debridement is required, a
second operative procedure is performed. While the use of an antibiotic spacer is well
accepted, whether the spacer should immobilize the hip (a so-called "static" spacer) or allow
for range of motion (a so-called "articulating" spacer) is controversial. Proponents of
static spacers argue that immobilization of the periarticular soft tissues aids in clearance
of the infection and that these spacers are simpler to fashion intraoperatively. Proponents
of articulating spacers argue that they improve hip function, prevent damage to the
musculature surrounding the hip, allow easier reimplantation, improve hip function, and
prevent dislocation following hip reimplantation. While good results have been described with
both methods, comparative trials have been conflicting as to whether spacer design alters hip
function, operative time, and dislocation rates. Equipoise exists within the literature, and
no randomized clinical trial has been conducted to evaluate this issue.
The purpose of this study is to compare articulating and static antibiotic-impregnated
spacers for the treatment of chronic periprosthetic infection complicating total hip
arthroplasty through a prospective, randomized clinical trial. The goals of this trial are to
determine the effect of spacer design upon eradication of infection, hip function, ease of
reimplantation, and dislocation rates. The investigators hypothesize that articulating
spacers will provide shorter operative times at replantation while improving hip function and
hip dislocation rates following hip reimplantation.
After diagnosis of infection and informed consent, patients will be taken to the operating
room. After anesthetization, patients will be randomized to either an articulating spacer or
static spacer. Randomization will be performed by prepared opaque envelopes administered by a
nonparticipant in the study. After a complete debridement of devitalized tissue, explantation
of infected components and any associated cement, either an articulating or static spacer
will be placed. All spacers will be formed using 3.0 g of Vancomycin and 1.0 g of Tobramycin
for each 40 g packet of cement. Articulating spacers will be formed of antibiotic-impregnated
cement using the Stage One system (Biomet, Warsaw, IN) sized to fit the endosteal and
acetabular bone defect. Static spacers will be hand-made with a rod of antibiotic-impregnated
cement and cement beads of sufficient quantity to fill the acetabulum.
Post-operatively, all patients will be made touch-down weight bearing protected with a walker
or crutches. At the time of reimplantation, the joint will be aspirated and multiple cultures
obtained along with intraoperative histopathological analysis to evaluate for persistent
infection.
Data collected preoperatively will include age, gender, laterality, etiology of hip
degeneration, comorbidities, Harris Hip score, infecting organisms and Paprosky femoral and
acetabular bone loss classification. The Harris Hip score has been used extensively in the
study of revision hip arthroplasty and has been found to be reliable and valid and will be
determined preoperatively and at all follow-up visits.
Data collected at the time of implant removal and reimplantation will include operative time,
blood loss, surgical approach, and need for an extended trochanteric osteotomy. Radiographs
performed immediately following and just prior to reimplantation will be reviewed to
determine if the spacer utilized has caused bone loss; bone loss to the cut bony surfaces
will be confirmed intraoperatively. At each follow-up visits radiographic appearance, the
Harris Hip Score, dislocation events, recurrence of infection, and the need for revision or
reoperation of any kind on the hip will be determined.
All portions of this study will be part of conventional care except for randomization and
collection of the Harris Hip Score. Which type of spacer is used currently depends upon the
judgment of the attending surgeons and both are used routinely.
The primary outcome variable will be Harris Hip Score. A power analysis was conducted with
the assistance of Dr. Mario Moric at Rush. Using the standard deviation of Harris Hip Scores
from Hsieh and colleagues (2004) and Fehring and colleagues (1999), the largest previous
studies reporting such data, Dr. Moric estimated 56 patients, 28 patients per group, would be
needed to detect a clinically relevant difference of ten points. To account for attrition,
our target total sample size will be 80 patients.
room. After anesthetization, patients will be randomized to either an articulating spacer or
static spacer. Randomization will be performed by prepared opaque envelopes administered by a
nonparticipant in the study. After a complete debridement of devitalized tissue, explantation
of infected components and any associated cement, either an articulating or static spacer
will be placed. All spacers will be formed using 3.0 g of Vancomycin and 1.0 g of Tobramycin
for each 40 g packet of cement. Articulating spacers will be formed of antibiotic-impregnated
cement using the Stage One system (Biomet, Warsaw, IN) sized to fit the endosteal and
acetabular bone defect. Static spacers will be hand-made with a rod of antibiotic-impregnated
cement and cement beads of sufficient quantity to fill the acetabulum.
Post-operatively, all patients will be made touch-down weight bearing protected with a walker
or crutches. At the time of reimplantation, the joint will be aspirated and multiple cultures
obtained along with intraoperative histopathological analysis to evaluate for persistent
infection.
Data collected preoperatively will include age, gender, laterality, etiology of hip
degeneration, comorbidities, Harris Hip score, infecting organisms and Paprosky femoral and
acetabular bone loss classification. The Harris Hip score has been used extensively in the
study of revision hip arthroplasty and has been found to be reliable and valid and will be
determined preoperatively and at all follow-up visits.
Data collected at the time of implant removal and reimplantation will include operative time,
blood loss, surgical approach, and need for an extended trochanteric osteotomy. Radiographs
performed immediately following and just prior to reimplantation will be reviewed to
determine if the spacer utilized has caused bone loss; bone loss to the cut bony surfaces
will be confirmed intraoperatively. At each follow-up visits radiographic appearance, the
Harris Hip Score, dislocation events, recurrence of infection, and the need for revision or
reoperation of any kind on the hip will be determined.
All portions of this study will be part of conventional care except for randomization and
collection of the Harris Hip Score. Which type of spacer is used currently depends upon the
judgment of the attending surgeons and both are used routinely.
The primary outcome variable will be Harris Hip Score. A power analysis was conducted with
the assistance of Dr. Mario Moric at Rush. Using the standard deviation of Harris Hip Scores
from Hsieh and colleagues (2004) and Fehring and colleagues (1999), the largest previous
studies reporting such data, Dr. Moric estimated 56 patients, 28 patients per group, would be
needed to detect a clinically relevant difference of ten points. To account for attrition,
our target total sample size will be 80 patients.
Inclusion Criteria:
1) Diagnosis of periprosthetic joint infection of a primary total hip arthroplasty with a
planned two-stage exchange procedure.
Exclusion Criteria:
1. Infection of a revision as opposed to a primary total hip arthroplasty
2. Medically unfit for operative intervention
3. Extensive bone loss preventing the use of an articulating spacer
4. Soft-tissue defects that prevent the use of an articulating spacer
5. Known allergy to polymethylmethacrylate, tobramycin or vancomycin.
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