Does cemented or cementless single-stage exchange arthroplasty of chronic periprosthetic hip infections provide similar infection rates to a two-stage? A systematic review.

BACKGROUND: The best surgical modality for treating chronic periprosthetic hip infections remains controversial, with a lack of randomised controlled studies. The aim of this systematic review is to compare the infection recurrence rate after a single-stage versus a two-stage exchange arthroplasty, and the rate of cemented versus cementless single-stage exchange arthroplasty for chronic periprosthetic hip infections. METHODS: We searched for eligible studies published up to December 2015. Full text or abstract in English were reviewed. We included studies reporting the infection recurrence rate as the outcome of interest following single- or two-stage exchange arthroplasty, or both, with a minimum follow-up of 12 months. Two reviewers independently abstracted data and appraised quality assessment. RESULTS: After study selection, 90 observational studies were included. The majority of studies were focused on a two-stage hip exchange arthroplasty (65 %), 18 % on a single-stage exchange, and only a 17 % were comparative studies. There was no statistically significant difference between a single-stage versus a two-stage exchange in terms of recurrence of infection in controlled studies (pooled odds ratio of 1.37 [95 % CI = 0.68-2.74, I2 = 45.5 %]). Similarly, the recurrence infection rate in cementless versus cemented single-stage hip exchanges failed to demonstrate a significant difference, due to the substantial heterogeneity among the studies. CONCLUSION: Despite the methodological limitations and the heterogeneity between single cohorts studies, if we considered only the available controlled studies no superiority was demonstrated between a single- and two-stage exchange at a minimum of 12 months follow-up. The overalapping of confidence intervals related to single-stage cementless and cemented hip exchanges, showed no superiority of either technique.

Calcium-Based, Antibiotic-Loaded Bone Substitute as an Implant Coating: A Pilot Clinical Study.

Background: Implant-related infections remain a major complication after orthopaedic surgery. Antibacterial coating of implants may prevent bacterial adhesion and biofilm formation. However, in spite of extensive preclinical research in the field, antibacterial coatings to protect orthopaedic implants in the clinical setting remain particularly few. The aim of the present study is to evaluate the safety of a calcium-based, antibiotic-loaded bone substitute as an antibacterial coating of cementless joint prosthesis. Methods: From March 2013 to August 2015, 20 consecutive patients scheduled for cementless or hybrid two-stage revision surgery for peri-prosthetic joint infection were included in this prospective, observational, pilot study. Cerament G or Cerament V, a gentamicin or vancomycin-loaded calcium-based resorbable bone substitute (60% calcium sulphate, 40% hydroxyapatite), was applied at surgery on the stem surface of hip (n=7) or knee (n=13) revision prosthesis. After surgery, all patients underwent clinical (HHS or KSS and SF-12 score), laboratory and radiographic evaluation at 3, 6 and 12 months and yearly thereafter. Results: At a minimum of 12 months follow-up, 19/20 (95%) patients showed no recurrence of infection and no signs of radiographic loosening of the stem. No adverse events were associated with the use of Cerament G or V. Conclusions: This is the first pilot clinical study on the short-term safety of using a calcium-based, gentamicin or vancomycin-loaded bone substitute as a surface coating on cementless prosthetic implants. If confirmed by larger studies and at longer follow-ups, these findings may open a new prospective to protect intra-operatively orthopedic implants from bacterial adhesion, through the use of resorbable, osteoconductive, antibiotic carriers.

ANTIBIOTIC-LOADED REGENOSS FOR THE TREATMENT OF SEPTIC BONE DEFECTS: IN VITRO STUDY AND PRELIMINARY CLINICAL EXPERIENCE.

Bone and joint infections are a difficult to treat condition, often associated with bone loss. Although the management of septic bone defects may currently be achieved through various treatment modalities, there is a continuous need for bone substitutes able at the same time to favour bone repair and to provide local antibacterial protection. RegenOss, a biomimetic and resorbable bone substitute, has been previously shown to be highly biocompatible and osteoconductive. Aims of the present study were to test the in vitro ability of RegenOss to act as a local carrier of antibiotics and to investigate its clinical safety and efficacy in a continuous series of patients, affected by bone loss in active or previous infection. In vitro study was performed by adding vancomycin, levofloxacin or meropenem and assessing elution properties of RegenOss at fixed time intervals by means of a microbiological assay. At 48 hours, 98.5% of meropenem, 94.1% of levofloxacin and 76.3% of vancomycin were recovered in the medium, while all antibiotics were completely eluted at seven days. Clinical safety and efficacy of vancomicyn- or vancomicyn and meropenem-loaded RegenOss had been tested in 13 consecutive patients. After the surgical procedure, each patient underwent clinical, laboratory and radiographic evaluation at 3, 6, 12, 18 and 24 months. No adverse events associated with the use of RegenOss were observed. Twelve patients showed no infection recurrence and ten satisfactory bone healing at follow-up. In conclusion, this study shows the ability of RegenOss to act as local carrier when loaded with three different antibiotics with a complete elution in one week. The clinical use of antibiotic-loaded RegenOss appears safe in this preliminary clinical series, while larger studies are needed to confirm the efficacy of the intra-operative combination of this biomimetic bone substitute with various antibacterials in the treatment of septic bone defects.

A comparative study of the use of bioactive glass S53P4 and antibiotic-loaded calcium-based bone substitutes in the treatment of chronic osteomyelitis: a retrospective comparative study.

The treatment of chronic osteomyelitis often includes surgical debridement and filling the resultant void with antibiotic-loaded polymethylmethacrylate cement, bone grafts or bone substitutes. Recently, the use of bioactive glass to treat bone defects in infections has been reported in a limited series of patients. However, no direct comparison between this biomaterial and antibiotic-loaded bone substitute has been performed. In this retrospective study, we compared the safety and efficacy of surgical debridement and local application of the bioactive glass S53P4 in a series of 27 patients affected by chronic osteomyelitis of the long bones (Group A) with two other series, treated respectively with an antibiotic-loaded hydroxyapatite and calcium sulphate compound (Group B; n = 27) or a mixture of tricalcium phosphate and an antibiotic-loaded demineralised bone matrix (Group C; n = 22). Systemic antibiotics were also used in all groups. After comparable periods of follow-up, the control of infection was similar in the three groups. In particular, 25 out of 27 (92.6%) patients of Group A, 24 out of 27 (88.9%) in Group B and 19 out of 22 (86.3%) in Group C showed no infection recurrence at means of 21.8 (12 to 36), 22.1 (12 to 36) and 21.5 (12 to 36) months follow-up, respectively, while Group A showed a reduced wound complication rate. Our results show that patients treated with a bioactive glass without local antibiotics achieved similar eradication of infection and less drainage than those treated with two different antibiotic-loaded calcium-based bone substitutes.

Two-stage revision of septic knee prosthesis with articulating knee spacers yields better infection eradication rate than one-stage or two-stage revision with static spacers.

PURPOSE: The best method for treating chronic periprosthetic knee infection remains controversial. Randomized, comparative studies on treatment modalities are lacking. This systematic review of the literature compares the infection eradication rate after two-stage versus one-stage revision and static versus articulating spacers in two-stage procedures. METHODS: We reviewed full-text papers and those with an abstract in English published from 1966 through 2011 that reported the success rate of infection eradication after one-stage or two-stage revision with two different types of spacers. RESULTS: In all, 6 original articles reporting the results after one-stage knee exchange arthoplasty (n = 204) and 38 papers reporting on two-stage revision (n = 1,421) were reviewed. The average success rate in the eradication of infection was 89.8% after a two-stage revision and 81.9% after a one-stage procedure at a mean follow-up of 44.7 and 40.7 months, respectively. The average infection eradication rate after a two-stage procedure was slightly, although significantly, higher when an articulating spacer rather than a static spacer was used (91.2 versus 87%). CONCLUSIONS: The methodological limitations of this study and the heterogeneous material in the studies reviewed notwithstanding, this systematic review shows that, on average, a two-stage procedure is associated with a higher rate of eradication of infection than one-stage revision for septic knee prosthesis and that articulating spacers are associated with a lower recurrence of infection than static spacers at a comparable mean duration of follow-up. LEVEL OF EVIDENCE: IV.

Gait analysis in patients with a preformed articulated knee spacer.

Two-stage revision is one of the most widely accepted procedures to eradicate infection and restore function in infected knee prosthesis; while the use of an articulated spacers is advocated by many as a means to preserve function between stages, no data are available regarding gait parameters after spacer implant. The aim of present study was to assess and compare the gait parameters of patients with articulated knee spacers with a normal reference population and with the sound limb. Computerised gait analysis, was performed 8 to 14 weeks after the infected knee prosthesis had been removed and a preformed, articulated, knee spacer had been implanted, in 10 consecutive patients. Kinematic data show a mean gait velocity reduction of 70% and a decrease of the range of motion of the operated knee of 59%, compared with controls. While ground reaction forces were only slightly reduced, frontal and sagittal moments and calculated powers around the affected knees were near zero or zero. Our findings point out the ability of a preformed articulated spacer to preserve, although reduced, the normal gait parameters and joint range of motion and the capacity of the human body to provide useful postural modifications, even in the absence of the proprioceptive input from a normal knee or from a traditional total knee replacement.

Telethermographic findings after uncomplicated and septic total knee replacement.

Thermal imaging with infrared thermography is a noninvasive approach to monitoring surgical site healing and detecting septic complications. The aim of this study was to set reference values for telethermographic patterns of wound healing after total knee replacement (TKR) not complicated by infection and to compare them against thermograms from patients with knee prosthesis infection. Forty consecutive patients operated for TKR underwent telethermography of the operated and the contralateral knee before and up to 12 months after uncomplicated surgery. The imaging data sets were then compared against those obtained starting 8 months after TKR in 15 other patients with diagnosed periprosthetic infection. Presurgical assessment thermograms showed no difference between the affected and the healthy knees. At assessment 3 days postoperative, the temperature of the operated knee had increased markedly, with a peak differential temperature (operated minus non-operated knee joint temperature) of 3.4±0.7°C; measurement at 90 days after surgery showed a return to baseline knee joint temperature in the patients with uncomplicated surgery. In the patients with septic complications, the mean differential temperature was 1.6±0.6°C (range, 1.1-2.5°C). Thermal imaging showed a measurable, reproducible telethermographic pattern of surgical site healing in patients with uncomplicated TKR and an elevated mean differential temperature >1.0°C in those with persistent prosthesis infection.