Surgical treatment of Hip PJI by resection of the infected implants and tissue and placement of a “spacer” which elutes antibiotic via antibiotic loaded cement is an accepted treatment option. There is some controversy over whether this “spacer” should be articulating or static. Proponents of the articulating option argue that there is improved function and maintenance of the soft tissue envelop. Critics have suggested that additional biomaterials may compromise eradication of infection. This study compares our results of the 2 treatment options. A review of our institutional PJI database between 2016 and 2021 identified 87 patients who were treated with resection arthroplasty for unilateral total hip PJI. The cohort was analyzed for demographics and type for surgery, as well as medical comorbidities, survivorship, and treatment success. 44 patients were female, the mean age of all patients was 62. 44 patients were treated with Articulating apacers, and 43 patients treated with static spacers. There was no significant difference between ASA or Elixhauser score, and no significant difference between mortality or treatment failure. This study did not show any difference between the patients who receive static spacers, from those who received articulating spacers, and deomstrated similar treatment success rates. From this data there does not appear to be any difference in success rates between those patients that were treated with static spacers and those that were treated with articulating spacers

Background. The purpose of this multi-center, randomized clinical trial was to compare static and articulating spacers in the treatment of PJI complicating total knee arthroplasty TKA. Methods. 68 Patients treated with two-stage exchange arthroplasty were randomized to either a static (32 patients) or an articulating (36 patients) spacer. A power analysis determined that 28 patients per group were necessary to detect a 13º difference in range of motion between groups. Six patients were excluded after randomization, six died, and seven were lost to follow-up prior to two years. Results. Patients in the static group had a hospital length of stay that was one day greater than the articulating group (6.1 vs. 5.1 days; p=0.032); no other differences were noted perioperatively. At a mean 3.5 years (range, 2.0 to 6.4 years), 49 patients were available for evaluation. Mean motion arc in the articulating group was 113.0º compared to 100.2º in the static group (p=0.001). The mean Knee Society Score was significantly higher in the articulating cohort (79.4 vs. 69.8 points; p=0.043). Although not significantly different with the sample size studied, static spacers were associated with a greater need for an extensile exposure at the time of reimplantation (16.7% vs. 3.8%) and a higher rate of reoperation (33.3% vs. 12.0%). Conclusions. Articulating spacers provided significantly greater range of motion and better clinical outcomes scores. Static spacers also appeared to affect early postoperative rehabilitation, as evidenced by a longer hospital stay following removal of the infected implant and were associated with a trend towards a greater need for extensile exposures at the time of reimplantation. Further, while it has been commonly believed that static spacers would improve infection control, there was no difference in the failure rate secondary to reinfection and there was a trend towards higher risk of reoperation in patients who received a static spacer. When the soft tissue envelope allows and if there is adequate bony support, an articulating spacer is associated with improved outcomes. For figures, tables, or references, please contact authors directly

The rate of periprosthetic joint infections (PJI) after primary total hip arthroplasty (THA) is approximately 1%. As the number of THAs performed each year continue to increase (550,000 by 2030), a corresponding increase in the number of hip PJI cases is likely to occur. A chronic deep infection may be treated by either chronic suppression, irrigation and debridement, single-stage exchange, or two-stage exchange. In the United States, the gold standard for chronic PJI continues to be a two-stage exchange. The benefit of an antibiotic impregnated cement is that they produce higher local concentrations of antibiotics than systemic intravenous administration. Hip spacers may be either static or articulating. Static spacers are reserved for cases of massive acetabular bone loss in which an articulating spacer is not feasible. A static spacer consists of a block of antibiotic cement in the native acetabulum and antibiotic coated rod in the femoral canal. Limb shortening, loss of soft tissue planes, and disuse osteopenia and muscle atrophy are all limitations of static spacers. In contrast, articulating spacers fulfill the goals of the interim construct during two-stage exchange which is to enhance eradication of the infecting organism through drug elution, to maintain limb length, to facilitate exposure during revision surgery, and to improve functional mobilization. Articulating spacers may be divided into three general categories based on method of spacer creation: Handmade custom spacers, prefabricated spacers, custom molded spacers (hemiarthroplasty molds and molded stem with cemented all-polyethylene cup). Handmade custom spacers are usually created with K-wire or rush rods coated with antibiotic cement. Handmade spacers are relatively simple to make, they are economical, and the amount and type of antibiotics incorporated can be customised for the infecting organism. Commercially available hemiarthroplasty spacers can be either prefabricated (Spacer G, Exactech, Gainesville. FL) or made intraoperatively (Stage One, Zimmer Biomet, Warsaw, IN) are available in several head and stem sizes. The advantage of prefabricated spacers is that they do not require additional time to mold in the operating room. The downside of prefabricated spacers is that the antibiotic concentration and type is predetermined. A custom molded stem with cemented all-polyethylene cup can be made with off the shelf implants or used as part of a commercially available spacer (PROSTALAC, DePuy Synthes, Warsaw, IN). A common antibiotic/cement combination includes Tobramycin (3.6 g/40 g of cement) and vancomycin (1.5 g/40 g of cement). In all of these spacer constructs, the principles of using a high-elution cement mixed without a vacuum and with high doses of heat stable antibiotics are consistent. Tobramycin works synergistically to improve Vancomycin elution properties and is usually added in higher doses. Overall infection eradication is similar between all categories of spacers and range between 90–97%. Complications after placement of an articulating spacer are often specific to the type of spacer used. Handmade spaces that have K-wires for support are at risk for spacer cement fracture. Spacer dislocation is also a common complication in up to 15% of cases with all types of spacers. In addition, periprosthetic fractures can occur postoperatively in up to 10% of patients. Overall, despite this complication profile, articulating antibiotic spacers have excellent rates of infection eradication and offer improved mobilization in the interim two stage period and reduce operative time, complexity, and morbidity during reimplantation

Aim. The primary endpoint of this study is to characterize the progression of bone defects at the femoral and tibial side in patients who sustained PJI of the knee that underwent two-stage revision with spacer implantation. In addition, we want to analyze the differences between functional moulded and hand-made spacers. Methods. A retrospective analysis of patients that underwent two-stage revision due to PJI of the knee between January 2014 and December 2021 at our institution. Diagnosis of infection was based on the criteria of the Muscoloskeletal Infection Society. The bone defect evaluation was performed intraoperatively based on the AORI classification. The basal evaluation was performed at the time the resection arthroplasty and spacer implantation surgery. The final evaluation was performed at the second-stage surgery, at the time of spacer removal and revision implant positioning. The differences between groups were characterized by using T-test student for continuous variables, and by using chi-square for categorical variables. A p-value < 0.05 was defined as significant. Results. Complete data of 37 two-stage TKAs revision were included in the study. An articulating moulded functional spacer was used in 14 (35.9%) cases, while a hand-made spacer was used in 23 (58.9%) cases. The average length of interval period (excluding the time for patients that retained the spacer) was 146.6 days. A bone defects progression based on the AORI classification was documented in 24 cases at the femoral side (61.6%), a bone defect progression was documented in 17 cases at the tibial side (43.6%), and a bone defect at both sides was documented in 13 cases (33.3%). A statistically significant greater bone defect progression at the tibial side was observed when hand-made spacers were used. A complication during the interval period was reported in five cases (12.8%) and postoperative complication was reported in 9 cases (23.1%). Conclusions. When comparing patients in which a functional articulating spacer was used, with patients in which static spacer was used, we reported a statistically significant reduced bone defect progression during the interval period at the femoral side only when moulded spacers were used. We observed a higher incidence of bone defect progression also at the tibial and both sides when hand-made spacers were used. This is the first study that documented the bone defect progression during two-stage revision of the knee, the results observed in this study are very encouraging

Two stage exchange treatment of the infected TKA involves two separate surgical procedures separated by an interval of several weeks of pathogen specific antibiotic therapy. The first stage involves removal of all of the infected arthroplasty components and any cement or foreign material, followed by aggressive debridement of nonviable bone and soft tissues. This is followed by placement of an antibiotic-laden spacer which may be either static (molded solid PMMA block) or mobile (shaped blocks or implants that allow knee motion). With both static and mobile spacers high local doses of antibiotic are delivered from the cement in addition to systemic antibiotic therapy usually employing an IV for around 6 weeks post debridement. The choice between static and mobile spacers is dictated by surgeon preference, soft tissue status (i.e. need for adjunctive muscle flaps), and by the severity of bone loss present with static spacers more likely to be used for more major soft tissue or bone defect cases. Mobile spacers have the advantage of allowing interval motion of the knee which may improve final range of motion. Static spacers usually require adjunctive brace or cast immobilization to prevent migration and bone damage. The second stage is performed at around 6 to 8 weeks after completion of systemic antibiotic therapy and preferably after normalization (or improvement) in laboratory indicators such as ESR and CRP. Routine repeat aspiration of all knees before reimplantation is not usual, but selective aspiration for culture may be helpful if concern exists that infection may still be present due to systemic signs, wound appearance or abnormal laboratory parameters. The second stage procedure involves removal of the antibiotic-laden spacer, repeat complete debridement of the knee, and insertion of revision knee components. Frequently adjunctive stems, blocks, cones or sleeves are needed to achieve adequate implant fixation due to associated bone loss. Careful attention to soft tissue balancing is required at the time of reimplantation in order to optimise motion and function while also avoiding laxity or maltracking. Two stage exchange remains the gold standard in North America for the management of infected TKA. While this method is used by some surgeons for all chronically infected TKA patients, it is employed even by most one stage exchange devotees when the infecting organism is unknown, infection involves a highly resistant or difficult to manage pathogen (i.e. fungal), is associated with a sinus track or marginal soft tissues, or in many cases of immunocompromised patients or those with multiple comorbidities

Two-stage treatment of chronically infected TKA is the most common form of management in North America and most parts of the world. One-stage management has pros and cons which will not be discussed in this lecture. There is great variation of techniques and timing and little data to definitively support one technique or timing approach vs. another. Most methods are based on empirical success and logic. At the time of surgery, the first step is removal of infected implants. All metallic implants and cement should be removed. The most common places to leave cement behind inadvertently include patellar lug holes, femoral lug holes, and the anterior proximal tibia behind the tibial tubercle. Formal synovectomy should be performed. The next step is typically antibiotic-impregnated spacer placement. There are pros and cons of dynamic and static spacers with no clear evidence of superiority of one vs. another. Dynamic spacers work satisfactorily with mild to moderate bone loss, but more severe bone loss is usually better treated with static spacers and a cast. Most antibiotic spacers are made of methyl methacrylate cement with addition of high-dose antibiotics. In most cases, doses of 4–8 gm of antibiotics per pack of cement are preferred. The type of dosing depends on the specific antibiotic and the type of cement used. The most common antibiotics used are vancomycin and gentamycin. When the femoral canals have been instrumented, antibiotic-impregnated cement wands are usually placed in the medullary canal, as the medullary canals have been shown to have high risk of residual bacteria being present. The resection interval may vary and there is no clear evidence of a “best” resection interval. Practically speaking, most surgeons use a resection period of 8–16 weeks depending on the type of spacer utilised. During the resection interval, serum markers (ESR and CRP) are followed periodically. One anticipates a decline or normalization of these parameters prior to second stage reimplantation procedure. There has not been a demonstrated advantage to reaspiration of the knee before reimplantation in most circumstances. At the time of reimplantation, the spacers are removed and the knee is redebrided. The key at the time of reimplantation is to obtain good implant fixation but to also balance this with the potential for manageable extraction of the implants at some later date. Good implant fixation is important because failure rates due to mechanical failure are approximately equal to those of failure due to reinfection by 10 years. It is important to remember that reinfection risk is at least 10% by ten years, and therefore extractability of implants is also important. Post-operative management typically includes IV antibiotics, followed by oral antibiotics until final intra-operative cultures are available. The results of two-stage reimplantation are reported in many series. Most show approximately 85–95% rate of successful eradication of infection in the first five years. Reinfections, often with different organisms, may occur even late after reimplantation. By ten years after surgery survival free of mechanical failure and infection in most series drops to 80% or less due to recurrent infections and mechanical failures

Purpose. Infection following total knee arthroplasty is a devastating complication, requiring considerable effort on the part of the surgeon to eradicate the infection and restore joint function. Two-stage revision is the standard of care in the treatment of peri-prosthetic infection, using a temporary antibiotic-impregnated spacer between procedures. However, controversy remains concerning the use of static versus dynamic spacers, as well as the spacer material. The purpose of this study was to evaluate the clinical outcomes and complications of two-stage revision total knee arthroplasty in patients treated with a metal-on-polyethylene articulating spacer, as compared to those treated with a static antibiotic-impregnated cement spacer at the same centre. Method. Twenty-seven knees in patients with a mean age of 65 years (range, 40 to 80 years) were treated with two-stage revision of an infected total knee arthroplasty using a metal-on-polyethylene dynamic prosthetic spacer fixed with antibiotic-impregnated cement. Clinical outcomes were evaluated using maximum active knee range of motion, as well as modified Knee Society knee scores and incidence of re-infection at a minimum one-year follow-up. The results were compared to those achieved at similar follow-up in 10 patients treated with a static cement spacer. Demographic profile as measured by age and gender, and pre-operative Knee Society scores and range of motion were similar between the two groups. Results. At a mean of twenty-five months following re-implantation (range, 12 to 50 months), the patients treated with dynamic spacers had significantly higher Knee Society scores (mean 93 points, range 77 to 100 points) as compared to the group treated with static spacers (mean 76 points, range 59 to 89 points; p=0.039). Additionally, mean range of motion at final follow-up was substantially higher in the patients treated with dynamic spacers (mean 102 degrees, range 60 to 120 degrees versus mean 92 degrees, range 40 to 120 degrees). There was one re-infection in the dynamic spacer group (3.7%), in a patient whos clinical course was previously complicated by subluxation of the dynamic spacer between procedures. Otherwise, no gross loosening or fractures of the dynamic spacers were noted. Conclusion. The results of this study suggest that the use of a cemented metal-on-polyethylene dynamic prosthetic spacer at the time of two-stage revision knee arthroplasty is similarly effective in eradicating peri-prosthetic infections when compared to the use of a cemented static spacer, while providing better clinical outcomes at short-term follow-up. Additionally, this spacer design provides a degree of mobility and knee function between procedures that is unachievable with a static construct, and appears to eliminate the potential complication of spacer fracture associated with pre-formed cement implants. The authors await further data to confirm these findings at longer-term follow-up

Introduction: The current gold standard for the treatment of the infected total knee arthroplasty is a two-stage revision. The purpose of this study is to present our results with two-stage revision arthroplasty in a series of 48 infected TKAs. Materials and Methods: Over a 10-year period (1996–2005) we have performed 2140 TKAs. Of them 48 (48 patients) were infected and required a two-stage revision arthroplasty (2.2% infection rate). In 43 patients of these patients we used LCCK prostheses (Zimmer, USA) and in 5 (with severe instability) a rotating hinge prosthesis (Waldemar Link, Germany). In 26 occasions antibiotics-loaded cement (Palacos with gentamicine) was used and in 22 we used articulated spacers. The average age of patients was 67 years (range, 59–82) and the average follow-up was 5.5 years (range: 1–10). The results were assessed according to the Knee Society scores. Results: Four knees were re-infected. Results were excellent in 28 knees, good in 13, fair in 3 and poor in 4 (the four re-infected prostheses). The four infected prostheses had been treated by static spacers. The survival rate taking as end-point removal of components for infection is 91.6% (results at average of 5.5 years). Conclusion: Our results confirm that two-stage revision TKA is a reproducible procedure in the infected primary TKA. Also that articulated antibiotic-loaded spacers seem to be better than static spacers

2 stage revisions of infected knee replacements using a static spacer are complicated by poor patient mobility between stages and the need for extensive soft tissue releases at the second stage. In this study we hypothesised that the use of the resterilsed components as temporary functional spacers, maintains patient function, and reduces soft tissue releases at second stage without reducing the rate of septic failure and obviating the need for expensive purpose made spacers. Method We report our series of seven two-stage revisions of infected total knee replacements using the resterilised femoral and tibial components as a temporary articulating spacers. This was compared to a second cohort of 6 patients in which the standard “hamburger” static spacer was used. Outcomes measured include reinfection rates, interval mobility, final range of movement, and bone loss. Results The articulating spacer allowed more comfortable function between stages and obviated the need for rectus snips and tibial tubercle osteotomies for exposure at the second stage. There was less bone loss in the articulating group requiring less stems or augments. The range of movement averaged 88 degrees at 9.3 months compared to 80 degrees at 9.2 months in the “static” cohort. There were no reinfections in either group. Discussion We have shown that this is a safe and effective way of treating infected knee arthroplasties with significant advantages for the surgeon and patient over more traditional methods

Purpose of the study: We report an unusual complication of patella tendon rupture that occurred secondary to the use of static cement spacer blocks in a series of three patients undergoing staged revision total knee arthroplasty (TKA) for infection. Methods and results: 3 male patients developed patella tendon injury secondary to anterior subluxation of static cement spacer blocks used at the first of a two-stage revision procedure for infected TKA. Average patient age was 70 years. The interval between the 1st and the 2nd stages varied between 3.5 to 24 months. At the second stage, it was observed that the patella tendon was completely severed and irreparable in one case, whereas it was partially injured and repairable in the other two cases. In the case with irreparable tendon injury, stable joint reconstruction could not be achieved at the second stage and ultimately resulted in knee arthrodesis. In the other two cases, 2nd stage revision was performed using hinged revision knee components and the tendon injury was repaired and protected with a circlage wire. None of the patients were satisfied with their outcome at the final review. Conclusion: This is the first report in the literature reporting the complication of patella tendon rupture secondary to the use of static cement spacer blocks in staged revision knee arthroplasty. The injury can either be repairable or irreparable. The functional outcome and satisfaction is not good after the salvage procedures. Therefore, we recommend that these spacer blocks should not be used in revision knee arthroplasty

Introduction. Extraction of implants due to periprosthetic infection (PJI) following complex revision total knee arthroplasty (rTKA) with extensive hardware can be a daunting undertaking for surgeon and patient alike. We question whether irrigation and debridement (I&D) has a role in this difficult situation with respect to infection control, reoperation, and function. Methods. rTKAs for PJI from 2005–2016 were reviewed. Extensive hardware was defined as: metaphyseal cone/sleeve fixation, distal femoral replacement, periprosthetic fracture hardware, or stems >75mm. Cases were categorized by treatment (I&D or 2-stage exchange). Results. 87 patients were identified with extensive hardware and PJI − 63 I&Ds and 42 2-stages. Follow-up was 3.7 years. Success defined as no re-operation for infection was similar − 38/63 (60.3%) I&D vs 28/42 (66.7%) 2-stage (p=0.54). 26/42 (61.9%) 2-stages required static spacers for post-extraction bone loss or wound problems. Only 14/42 (33%) 2-stages were successfully replanted without re-infection. 11/42 (26.1%) 2-stages had retained spacers while 7/42 (16.7%) 2-stages were eventually fused. In contrast, 38/63 (60.3%) I&Ds maintained original implants without further surgery. 8/63 (12.7%) required repeat I&D; 9/63 (14.3%) underwent eventual 2-stage. Chronic antibiotic suppression was utilized in 53/63 (84.1%) I&Ds and 17/42 (40.5%) 2-stages (p<0.001). Amputation rates were similar − 9/63 (14.3%) I&D vs 7/42 (16.7%) 2-stage (p=0.79). Ambulatory rates were similar − 46/63 (73.0%) I&D vs 24/42 (57.1%) 2-stage (p=0.09). More patients who underwent I&D had a functional TKA at final follow-up (53/63 (84.1%) I&D vs 20/42 (47.6%) 2-stage; p<0.001). Mortality was high − 22/59 (37.3%) I&D vs 13/37 (35.1%) 2-stage (p=1.00). Conclusion. In the setting of PJI following rTKA with extensive hardware, morbidity and mortality is high. I&D with chronic suppression appears as effective as 2-stage procedures in preventing reoperation for infection and maintaining ambulatory status while avoiding the morbidity of 2-stage exchange

Introduction and Aims: To compare the results of patients treated with articulating versus static antibiotic-impregnated spacers for infected knee arthroplasty. Method: All patients undergoing two-stage revision knee arthroplasty for sepsis in the last five years were reviewed. Twenty-six patients had been treated with articulating spacers. This group was compared to 36 patients treated with static spacers. The articulating spacer technique had been adopted more recently than the static technique. Minimum follow-up was 12 months from second stage re-implantation (average 22 months articulating, 40 months static). Patients were compared in terms of the need for extensile exposures required for re-implantation, range of motion at most recent review, eradication of infection and augmentation required on revision implants. Results: In the articulating group, fewer extensile exposure methods were required at second-stage prosthesis re-implantation (19% vs 36%). No tibial tuberosity osteotomies have been required since using the articulating spacer. The articulating group demonstrated a significantly improved range of flexion compared to the static group (106 vs 97 degrees – p=0.045) and had fewer patients with significant loss of extension or quadriceps lag. Eradication of infection was improved in the articulating group (92% vs 82%) but at shorter average follow-up. The need for augments and stabilised prostheses at revision surgery as a measure of bone loss was no different between the groups but was related to the number of prior surgical procedures. Conclusion: Articulating cement spacers facilitate reimplantation surgery by maintaining tissue planes and joint mobility without compromising joint stability or eradication rate of infection. Patients demonstrate better range of motion and less complications related to the extensor mechanism with the articulated spacer

At first-stage revision surgery for infection of total knee arthroplasties, antibiotic-impregnated cement spacers are frequently implanted. Two types of cement spacers are commonly used, “static” and “articulating” cement spacers. Advocates of cement spacers state that they deliver high doses of antibiotics locally, increase patient comfort, allow mobility and provide joint stability. They also minimize contracture of collateral ligaments, thereby facilitating re-implantation of a definitive prosthesis at a later stage. The use of these cement spacers, however, are not without significant complications, including patella tendon injuries. We describe a series of three patients who sustained patella tendon injuries in infected total knee arthroplasties following the use of a static cement spacer at first-stage knee revision. The patella tendon injuries resulted in significant compromise to wound healing and knee stability requiring multiple surgeries. The mid-term function was poor with an Oxford score at 24 months ranging from 12–20. Based on our experience, we advise caution in the use of static cement spacer blocks. If they are to be used, we recommend that they should be keyed in the bone to prevent patella tendon injuries

In recent years articulating cement spacers have been used to treat infected knee arthroplasty. The aim has been to better maintain tissue planes and joint mobility thereby improving second stage re-implantation surgery. Two groups of patients treated for infected knee arthroplasty were reviewed. Twenty-six patients with articulating and forty patients with static antibiotic-impregnated methyl-methacrylate spacers were compared. The articulating spacers demonstrated easier surgical exposure at second stage and improved range of knee motion after re-implantation. There was no compromise in the rate of infection eradication with articulating spacers. Bone loss at revision was independent of spacer type. To compare the results of patients treated with articulating versus static antibiotic-impregnated spacers for infected knee arthroplasty. Articulating cement spacers facilitate re-implantation surgery by maintaining tissue planes and joint mobility without compromising joint stability or eradication rate of infection. Patients demonstrate better range of motion and less complications related to the extensor mechanism with the articulated spacer. Antibiotic impregnated methyl-methacrylate spacers have become a mainstay in two-stage revision arthroplasty for sepsis. It is thought that articulating cement spacers facilitate prosthesis re-insertion by better maintaining tissue planes and joint mobility between stages. In the articulating group fewer extensile exposure methods were required at second stage prosthesis reimplantation (19% vs 36 %). No tibial tuberosity osteotomies have been required since using the articulating spacer. The articulating group demonstrated a significantly improved range of flexion compared to the static group(106 vs 97 degrees- p=0.045) and had fewer patients with significant loss of extension or quadriceps lag. Eradication of infection was improved in the articulating group (92% vs 82%) but at shorter average follow-up. The need for augments and stabilized prostheses at revision surgery as a measure of bone loss was no different between the groups but was related to the number of prior surgical procedures. Twenty-six patients treated with articulating spacers were compared to a matched consecutive group of forty patients treated with static spacers. Minimum follow-up was twelve months from second stage re-implantation (average twenty-two months articulating, forty months static). Funding: No direct funding from any commercial source has been received for this study. The primary author’s fellowship position is partially funded by Smith and Nephew Richards Inc

In recent years articulating cement spacers have been used to treat infected knee arthroplasty. The aim has been to better maintain tissue planes and joint mobility thereby improving second stage re-implantation surgery. Two groups of patients treated for infected knee arthroplasty were reviewed. Twenty-six patients with articulating and forty patients with static antibiotic-impregnated methyl-methacrylate spacers were compared. The articulating spacers demonstrated easier surgical exposure at second stage and improved range of knee motion after re-implantation. There was no compromise in the rate of infection eradication with articulating spacers. Bone loss at revision was independent of spacer type. To compare the results of patients treated with articulating versus static antibiotic-impregnated spacers for infected knee arthroplasty. Articulating cement spacers facilitate re-implantation surgery by maintaining tissue planes and joint mobility without compromising joint stability or eradication rate of infection. Patients demonstrate better range of motion and less complications related to the extensor mechanism with the articulated spacer. Antibiotic impregnated methyl-methacrylate spacers have become a mainstay in two-stage revision arthroplasty for sepsis. It is thought that articulating cement spacers facilitate prosthesis re-insertion by better maintaining tissue planes and joint mobility between stages. In the articulating group fewer extensile exposure methods were required at second stage prosthesis reimplantation (19% vs 36 %). No tibial tuberosity osteotomies have been required since using the articulating spacer. The articulating group demonstrated a significantly improved range of flexion compared to the static group(106 vs 97 degrees- p=0.045) and had fewer patients with significant loss of extension or quadriceps lag. Eradication of infection was improved in the articulating group (92% vs 82%) but at shorter average follow-up. The need for augments and stabilized prostheses at revision surgery as a measure of bone loss was no different between the groups but was related to the number of prior surgical procedures. Twenty-six patients treated with articulating spacers were compared to a matched consecutive group of forty patients treated with static spacers. Minimum follow-up was twelve months from second stage re-implantation (average twenty-two months articulating, forty months static). Funding: No direct funding from any commercial source has been received for this study. The primary author’s fellowship position is partially funded by Smith and Nephew Richards Inc

Infection after total knee arthroplasty poses formidable challenges to the surgeon. Once an infection is diagnosed, the identification of the organism and its sensitivity to antibiotics is essential. The host's healing capacity is vital. Optimisation of modifiable comorbidities, supplemental nutrition and cessation of smoking can improve wound healing. Surgical goals include debridement of necrotic tissue and elimination of the dead space. Intravenous antibiotics and a two-stage protocol are the standard of care. At our institution, the first stage is performed with an implant and antibiotic-cement composite. This articulating spacer maintains limb length and tissue compliance. The patient can maintain a functional status between stages. Definitive reconstruction is more readily accomplished with this method in contrast to the static spacer approach. The clinical efficacy of this protocol has been well documented in the literature

Aims

To explore the clinical efficacy of using two different types of articulating spacers in two-stage revision for chronic knee periprosthetic joint infection (kPJI).

Introduction. Proper soft-tissue balance is important for achieving favorable clinical outcomes following TKA, as ligament imbalance can lead to pain, stiffness or instability, accelerated polyethylene wear, and premature failure of implants. Until recently, soft-tissue balancing was accomplished by subjective surgeon feel and by use of static spacer blocks. Now, nanonsensor-embedded implant trials allow surgeons to quantify peak load and center of load in the medial and lateral compartments during the procedure, and to adjust ligament tension and implant positioning accordingly. The purpose of this 3-year, multicenter study is to evaluate 500 patients who have received primary TKA with the use of intraoperative sensors in order to correlate quantified ligament balance to clinical outcomes. Methods. To date, 7 centers have contributed 215 patients who have undergone primary TKA with the use of intraoperative sensors. Patients are seen at a pre-operative visit (within 3 months prior to surgery), and post-operatively at 6 weeks, 6 months, and at 1, 2, and 3-year anniversaries. Standard demographic and surgical data is collected for each patient, including: age at time of surgery, BMI, operative side, gender, race, and primary diagnosis. At each interval, anatomic alignment and range of motion are assessed; KSS and WOMAC evaluations are administered; and a set of standard radiographs is collected, including: standing anteroposterior, standing-lateral, and the sunrise patellar view. Intraoperative loads were recorded for pre- and post-release joint states. All soft-tissue release techniques were recorded. “Optimal” soft-tissue balance was defined as a medial-lateral load difference of less than or equal to 15 lbs. Results. The average age of this cohort was 70 years: 63% are female and 37% are male, with a mean BMI of 30.6. Ninety five percent of cases had a primary diagnosis of osteoarthritis. The majority of cases (72.5%) exhibited suboptimal soft-tissue balance (>15 lbs. of medial-lateral compartmental loading difference) prior to ligamentous release. Using the intraoperative sensor for guidance, 82% (p < .01) of patients were released and confirmed to exhibit a state of optimal joint balance at closure. Patient self-reported outcome scores—both KSS and WOMAC—showed significant improvement (p < .01) from the pre-operative interval to the 6-month follow-up interval. The average increase for KSS at 6 months was 60 points. Discussion. Optimized ligament balance using intraoperative sensors led to significant improvement in KSS and WOMAC scores at a 6-month follow-up interval in 215 knees. Notably, the 60-point average increase in KSS, at 6 months, is approximately 200% greater than historical data, obtained from existing literature, using traditional methods of TKA balancing. Measuring the effect of specific ligamentous releases on subsequent load and balance can potentially enable the development of release algorithms to guide surgeons to balance TKA using sensor data. Further, correlating quantifiable data on peak load and center of load to patient outcomes will help clarify what truly defines “optimum balance.” Additional study subject accrual and further longitudinal follow-up is needed to affirm the early observation that sensor-quantified soft-tissue balancing improves patient outcomes in TKA

Introduction Antibiotic-loaded cement spacers are commonly used in the two-stage management of the infected total knee replacement (TKR). Static spacer blocks make exposure and reimplantation difficult because of soft-tissue retraction and muscle shortening. To avoid these problems, a temporary articulating moulded implant has been recently introduced in the marketplace. The device is industrially preformed in three sizes (two articulating components), has standardised mechanical and pharmacological characteristics. Methods We present a multicentre study designed to assess the safety of the device, patients’ satisfaction and functional outcome at a minimum follow-up of six months. Twenty-four knees have been treated for TKR deep infection due to CNS (15),S.aureus (three),E.coli (one),mixed flora (two), unidentified (three). Continuous passive motion and partial/touch weight-bearing were started after surgery. Second-stage surgery was performed after normalisation of serological parameters, a minimum period of six weeks of antibiotic therapy, and a sterile aspiration of the joint. The spacer was removed and a new prosthesis was inserted in all patients. The mean implantation time of the spacer was 16 weeks (range 8 to 38). Results Suppression of infection was observed in all patients at a minimum follow-up of six months (mean 14 months). No spacer-related complication (instability, dislodgment, severe wear, fracture) was observed. The range of motion of the knees remained unchanged between the first and second stages and improved after definitive reimplantation. The mean Knee Society Score at last-follow up was 88 points (knee score and functional score). The patients judged the result excellent (three), good (15), satisfactory (five), poor (one). Conclusion The use of an articulating spacer in the two-stage treatment of infected TKR improves the quality of life of the patient, the ultimate range of motion, facilitates second-stage surgery and the functional recovery. Severe bone loss is a relative contraindication for articulating spacers, as these knee joints may require immobilisation during the resection time interval. In relation to the conduct of this study, one or more of the authors is in receipt of a research grant from a non-commercial source

Aims

Two-stage exchange revision total hip arthroplasty (THA) performed in case of periprosthetic joint infection (PJI) has been considered for many years as being the gold standard for the treatment of chronic infection. However, over the past decade, there have been concerns about its safety and its effectiveness. The purposes of our study were to investigate our practice, collecting the overall spacer complications, and then to analyze their risk factors.