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Introduction Periprosthetic joint infections (PJI) following unicompartmental knee arthroplasties (UKAs) will increase. The aim of this review is to evaluate current evidence regarding treatment options, complications, clinical and radiological outcomes of PJI management in UKAs. Methods A systematic review of English literature was performed. Retrospective and prospective studies providing treatment options, complications, clinical and radiological outcomes of PJI following UKAs were included. PJI type, treatment, survival rate with no reoperation for infection and survival rate with no reoperation for any cause were evaluated. Results Eleven articles were included. Three studies focusing on PJI following UKA (45 cases) report a survival rate with no reoperation for infection of 68.9% and a survival rate with no reoperation for any cause of 48.9%. Eight articles concerning UKA failure modes (28 cases) overestimate survival rate with no reoperation for infection (88.9%) and survival rate with no reoperation for any cause (88.9%) (p Conclusions Treatment strategy is determined by symptom timing, PJI type (acute vs chronic), causative organism, patient’s comorbidities. A longer duration of PJI or severe host and extremity status seems to require 2SE or 1SE. Patients who have a shorter duration of PJI could receive DAIR.

Revision total knee arthroplasty is a challenging procedure for every orthopaedic surgeon, especially when a megaprosthesis is involved. Possible surgical solutions in case of distal femur megaprosthesis revision are total femoral replacement (TFR) or amputation/disarticulation. TFR is affected by an extremely high rate of complications, while amputation/ disarticulation leads to unacceptable functional results. We report the case of a 59-year-old woman who underwent a staged left knee megaprosthesis revision for infection with massive femoral and tibial bone loss and complete disruption of extensor mechanism following 7 prior surgeries. To manage these problems, we developed a new, custom porous titanium endofemoral sleeve for the femoral side and a custom porous titanium cone for tibial reconstruction that were tailored to the patient’s specific bone loss and matched with the tumor prosthetic design used. A custom-made endofemoral sleeve may be a viable solution introducing an intermediate step between distal femur megaprosthesis and total femur substitution. Accurate and detailed surgical planning as well as intraoperative management of soft tissues and residual bone stock are key factors for optimal outcomes.

PurposeSeptic arthritis of the native joint is challenging for orthopedic surgeons because it may lead to wide bone defects and severe impairment of joint function. This study aimed to analyze clinical functional outcomes, the rate of infection eradication, and survival of implants of patients who underwent two-stage arthroplasty for septic arthritis of the hip and knee.MethodsA retrospective single-centre analysis was conducted of patients treated for septic arthritis of the hip and knee joints through a two-stage surgery between 2012 and 2015. Clinical and radiological records were gathered from the prospectively collected Institutional Arthroplasty Registry. Patients’ pre-operative Harris hip scores and Knee Society scores were compared with those obtained at the latest follow-up. Kaplan–Meier curves were generated to assess survival of implants.ResultsForty-seven patients were included. The mean follow-up was 85.2 ± 15.4 months. The Harris hip score improved from 39.4 ± 9.9 to 84.5 ± 10.8 points (p< 0.001). The Knee Society score improved from 40.7 ± 8.4 to 86.0 ± 7.8 points (p< 0.001). Knee Society score-function increased from 25.7 ± 14.2 to 85.4 ± 23.4 points (p< 0.001). The infection eradication rates were 92.0% and 90.9% in patients who underwent hip and knee operation, respectively (p= 0.891). Overall survivorship of implants after the second stage was 93.6%.ConclusionsTwo-stage arthroplasty provides good to excellent clinical outcomes in cases of active septic arthritis of the hip and the knee, high rates of infection control, and implant survival.

Objective: The primary aim was to evaluate the long-term follow-up of Collum Femoris Preserving (CFP) stem, specifically focusing on stem survivorship, complications, as well as on clinical and radiological results. The secondary study objective is an age-based sub-analysis (Materials and methods: We performed a retrospective analysis of patients who underwent CFP implantation between 1997 and 2009. A total of 311 patients (342 hips) were included with a mean follow-up of 15.8 ± 2.2 (range 11–24) years. 2 age groups were analysed: Group-Y (age Results: According to HSS score, 95% of patients reported excellent/good results (95.6% Group-Y vs. 94.4% Group-E) with an overall stem survival rate of 93.3% (94% Group-Y vs. 92.5% Group-E; p = 0.37). Overall, 87% of stem revisions were performed with primary stems. The rate of prosthetic components revision was 9.9 % (9.9% in Group-Y vs. 10% in Group-E; p = 1). The reoperation rate was 10.8% (11.5% in Group-Y vs. 10.0% in Group-E; p = 0.73). Conclusions: The CFP stem provides good clinical and radiological long-term results with low rate of complications in both young and elderly patients. No significant difference in stem revision and reoperation rates was observed between the 2 groups. Both in elderly and young patients, CFP stem allows revisions to be performed with primary stems.

Although the practice of metaphyseal reconstruction has obtained successful clinical and radiological results in revision total knee surgery, off-the-shelf devices aren’t an effective solution for all patients as they do not cover the full range of clinical possibilities. For this reason, during severe knee revisions, custom-made porous titanium cementless metaphyseal cones are nowadays employed as alternative to traditional surgeries. The aim of this study is to understand the benefits gained by the use of the custom-made cones against the performance of more traditional techniques, such as the use of cemented or cementless stems. Thus, a retrospective study on eleven patients and a biomechanical finite element analysis (FEA) was developed, based upon three clinical cases of the clinical analyzed cohort. Eleven patients underwent staged total knee arthroplasty revision with the use of 16 custom-made cones to correct severe femoral and tibial meta-diaphyseal bone defects. Clinical scores and range of movement were observed during the follow-up period (mean follow-up 26 ± 9.4 months). Reason for surgery was periprosthetic joint infection (PJI) in eight patients and post-traumatic osteomyelitis in the other three patients. Three patients previously affected by PJI were selected among the eleven patients of the clinical population. For those patients, bone geometries and implants during surgery were replicated in silico and analyzed during different daily activities. For the same patients, as alternative solution for surgery, the use of cemented or cementless stems was also simulated by FEA. Stress patterns in different region of interest and risk of fracture in the bone were calculated and compared. No loosening, component migration, or mismatches between preoperative planning and intraoperative findings were clinically registered. Biomechanical results demonstrated that the use of custom-made cones induces a more homogeneously distributed bone stress than the other two techniques that concentrate the stress in spotted regions. The risk of fracture is comparable between the use of custom-made cones and cemented technique, while press-fit configurations increase the risk of fracture (more than 35%). Based upon the clinical evidence and the findings after the FEAs, the practice of porous custom-made metaphyseal cones in severe revisions of knee arthroplasties is showing promising biomechanical results. The homogeneous stresses distributions and the lower bone stress gradient could justify a reduction of bone fractures and the risk of implant loosening which could be the explanation to the successful clinical outcomes.

Background: The management of acetabular bone loss is a challenging problem in revision total hip arthroplasty (rTHA). The goals of treatment are a stable acetabular fixation, implant stability, and restoration of hip centre of rotation. This study aims to report clinical, radiological outcomes and complications at short-term to mid-term follow-up of the cup-on-cup technique in the management of severe acetabular bone loss in rTHA. Methods: We retrospectively reviewed the records of patient receiving rTHA performed with double porous tantalum cup technique in a single Joint Replacement Unit from 2014 to 2017. Objective and subjective clinical scores (Harris Hip Score, Oxford Hip Score, and visual analogue scale), radiological parameters (centre of rotation, leg-length discrepancy, heterotopic ossification, osseointegration, loosening and radiolucencies) and complications were recorded. We analysed the implant survival rate and periprosthetic joint infection rate. Results: We included 9 patients (9 hips) with a mean follow-up of 35.3 ± 10.8 months. Functional scores showed a statistically significant improvement at the final follow-up ( p < 0.01). All patients rated their surgery as satisfactory. The cup-on-cup construct demonstrated radiological osseointegration with the centre of rotation restoration and leg length discrepancy improvement. In 1 patient, periprosthetic joint infection was diagnosed and treated with suppressive antibiotic therapy. No patients underwent acetabular components revision surgery for any reason. Conclusions: Cup-on-cup technique is a valid and safe solution for reconstruction of selected Paprosky type IIIA and IIIB bone defects with satisfactory clinical and radiographic results at short-term and mid-term follow-up.

Acetabular bone loss is a challenging problem in revision total hip arthroplasty (rTHA). Severe bone loss is not uncommon especially in periprosthetic joint infection. Surgical options, including revision shells, rings, and cages—with or without bone allograft—are affected by high complication rates and unsatisfactory clinical results. We report our mid-term results of non-flanged, custom-made acetabular components in staged rTHA. We retrospectively reviewed all patients undergoing two-stage revision with acetabular custom-made implants between 2014 and 2016 at a single institution. Harris Hip Scores, Oxford Hip Scores, and Visual Analogue Scales for pain were obtained, and radiographical follow-up was performed. Complications were reported and analysed. We included 19 patients (19 hips) with an average follow-up of 42.3 ± 11.8 months. At the time of re-implantation, significant acetabular bone loss according to Paprosky classification (IIC, IIIA-B, and pelvic discontinuity) was detected in our patients. Clinical outcomes showed statistically significant improvement from pre-operative visit to last follow-up (p < 0.01). All custom-made implants had radiological osseointegration, and we did not find any implant complications, such as loosening or malposition. No mismatch between pre-operative planning and intra-operative findings was observed. To date, we report one septic failure managed with second staged revision, and one re-operation for recurrent THA dislocation. Custom-made acetabular implants showed excellent clinical and radiographic mid-term outcomes with a low rate of related complications, providing implant stability on residual host bone, restoring hip biomechanics, and allowing biological osseointegration. Further long-term studies are needed to confirm preliminary results.

Introduction Unicompartmental knee arthroplasty (UKA) has an infection rate of 0.1–0.8%. Despite the wide amount of literature about septic total knee arthroplasty management, few data are available for UKA infection treatment. The aim is to present the clinical and radiological outcomes along with complication rates of a series of septic UKA treated with two-stage exchange. Methods We retrospectively reviewed 16 patient treated with staged UKA revision for infection between June 2015 and September 2019 in a single bone infection unit. The main demographic and surgical data were recorded. Clinical scores (VAS, KSS, OKS, postoperative ROM), radiological parameters (osseointegration, loosening and radiolucencies) and complications were reported. The mean follow-up was 33.5 ± 6.9 months. Results Mean age at surgery was 68.5 ± 9.1. All but two were medial UKA. The mean number of previous surgeries was 2.9 ± 1.9. The mean ROM, VAS, KSS and OKS of the entire population improved significantly (p Conclusion According to our results, staged revision represents a reliable ad effective option in delayed and late UKA infections. This technique provides optimal clinical and radiological results with acceptable complication rates. To the best of our knowledge, this represent the widest case series on infected UKA managed with two-stage exchange.

This study is a retrospective analysis of our experience in microsurgical bone transfers for complex limb reconstructions. The aim of this study is to evaluate reliability of the vascularized fibula technique: infection recurrence, hypertrophy, time to bone union, complications, and time to healing in severe osteomyelitis (Cierny-Mader III and IV) cases over a 38 to 93 month follow-up.From March 2010 until December 2015, 18 patients' limbs (6 females and 1 2 males; mean age 48.7 years) were reconstructed with 10 free fibula flaps, 5 pedicled fibula flaps, 3 peroneus brevis osteomuscular flaps. We reconstructed 2 radiuses, 2 ulnae, 4 femurs, 4 tibiae, 1 acetabulum and 3 fibular malleoli.We considered as successful results all cases where patients had successful functional bone reconstruction with no recurrence of infection during the follow up (mean time 63.6 months). We obtained 14 complete functional reconstructions, 2 limb salvages with impaired function, and 2 failures which underwent major amputations. In only one case there was an infection recurrence.The bone defect reconstruction with vascularized fibula grafts in severe bone infections is an effective option, but requires a well trained multidisciplinary team to manage the high rate of complications. Complications, in our series, were demonstrated to be significantly associated to patients defined as B-hosts according to Cierny-Mader's classification (P0.05), and caliber discrepancy between fibula and reconstructed bones such as Tibia and Femur (P0.005). Furthermore, stress fractures in the grafted fibulae were prognostic indicators for overall treatment failure (P0.05).Bei dieser Studie handelt es sich um eine retrospektive Analyse unserer Erfahrungen mit mikrochirurgischen Knochentransfers für komplexe Rekonstruktionen von Gliedmaßen. Ziel der Studie war es, die Zuverlässigkeit der Technik der vaskularisierten Fibula-Transplantation zu beurteilen: Infektionsrezidive, Hypertrophie, Zeit bis zur knöchernen Durchbauung, Komplikationen und Zeit bis zur Heilung bei Patienten mit schwerer Osteomyelitis (Grad III und IV nach Cierny- Mader) über einen Nachbeobachtungszeitraum von 38 bis 93 Monaten.Von März 2010 bis Dezember 2015 wurden Gliedmaßen von 18 Patienten (6 Frauen und 12 Männer; mittleres Alter 48,7 Jahre) mit 10 freien Fibula-Flaps, 5 gestielten Fibula-Flaps und 3 osteomuskulären Peroneus-brevis-Flaps rekonstruiert. Wir rekonstruierten 2 Radien, 2 Ulnae, 4 Femora, 4 Tibiae, 1 Acetabulum und 3 laterale Malleoli.Ein Operationsergebnis wurde als erfolgreich gewertet, wenn der Patient eine erfolgreiche funktionelle Knochenrekonstruktion erreichte und während der Nachbeobachtung (mittlerer Zeitraum 63,6 Monate) keine erneute Infektion auftrat. Unsere Ergebnisse waren wie folgt: 14 vollständige funktionelle Rekonstruktionen, 2 Gliedmaßenrettungen mit eingeschränkter Funktion und 2 fehlgeschlagene Eingriffe mit größeren Amputationen. Nur in einem Fall kam es zu einer erneuten Infektion.Die Rekonstruktion von Knochendefekten mit vaskularisierten Fibula-Transplantaten bei schweren Knocheninfektionen ist eine effektive Behandlungsoption. Sie erfordert jedoch ein versiertes multidisziplinäres Team zur Beherrschung der hohen Komplikationsrate. In unserer Studie traten Komplikationen in erster Linie bei Patienten auf, die gemäß der Cierny-Mader-Klassifikation als Wirte vom Typ B definiert wurden (p0,05), und bei Patienten mit einer Diskrepanz des Durchmessers zwischen Fibula und rekonstruiertem Knochen, z. B. Tibia und Femur (p0,005). Des Weiteren erwiesen sich Stressfrakturen als prognostische Indikationen für ein allgemeines Behandlungsversagen (p0,05).

PURPOSE Despite the standardization of two-stage knee revision protocols, a high percentage of failures still occurs. Identifying the predictors of failure is necessary to determine appropriate management and counsel for patients with a periprosthetic knee infection. This study aimed to identify risk factors predicting the failure, to describe implant survival, and to report the mid-term clinical outcomes of patients undergoing two-stage revision for periprosthetic knee infection. METHODS Data of patients who underwent two-stage knee revision from 2012 to 2016 were analyzed, and 108 patients were included. The mean age was 66.6 ± 9.2 years. The mean follow-up was 52.9 ± 15.6 months. Logistic regression was conducted to identify predictors of treatment failure. Kaplan-Meier curves were generated to assess implant survival. Preoperative functional outcomes were compared to those registered at the final follow-up. RESULTS Difficult-to-treat infections (OR = 4.2, 95% CI 1.2-14.5, p = 0.025), the number of previous surgeries (OR = 1.8, 95% CI 1.2-2.6, p = 0.005), and the level of tibial bone defect (OR = 2.3, 95% CI 1.1-4.7, p = 0.027) significantly predicted the failure of two-stage knee revision. Survivorship of implants was significantly lower for patients presenting these risk factors (p

The purposes of this study were to determine demographics and characteristics of patients who underwent spacer exchange for persistent infection in the setting of two-stage arthroplasty for periprosthetic joint infection, to describe the microbiology of pathogens involved, to analyze survivorship free from infection in these patients.The institutional prospectively collected database was reviewed to enroll patients with minimum 2 years follow-up. Patients who underwent two-stage procedure for septic arthritis were excluded, as were patients who had spacer fracture or dislocation.A total of 34 patients (41 procedures) were included. Mean age was 65.0 ± 12.8 years. Mean follow-up was 53.4 ± 24.8 months. Mean number of previous procedures was 3.6 ± 1.2. A total of 27 (79.4%) patients underwent final reimplantation. The most frequently isolated pathogen in spacer exchange was Staphylococcus epidermidis (10 cases, 28.6%). Polymicrobial cultures were obtained from 9 (25.71%) patients, 10 (28.6%) presented culture-negative infections. A total of 11 (32.4%) resistant pathogens were isolated, and 16 (47.0%) difficult to treat pathogens were detected. Eradication rate was 78.8%. Overall survivorship of implants after final reimplantation was 72.8% at 51.8 months.Surgeons should be aware that subjects necessitating spacer exchange often present multiple comorbidities, previous staged revision failures, soft-tissue impairment and difficult to treat infection. In these patients, spacer exchange provides good clinical results and infection eradication, preventing arthrodesis or amputation.

Few studies provide an analysis of conservative two-stage revision of hip periprosthetic joint infection (PJI) and its impact on final outcome. A conservative revision is defined when soft tissues and bone quality enable the use of primary prosthetic components. Data of patients treated for chronic hip PJI who underwent two-stage revision between 2009 and 2016 and had a minimum of 2 years of follow-up were collected. Oxford Hip Score (OHS), Harris Hip Score (HHS) and radiological and microbiological data were retrieved and analysed. Clinical and functional outcome, survival, mortality, eradication, reinfection and re-revision rates within subgroups of patients with primary components and revision components are reported herein. A total of 148 patients underwent two-stage hip exchange with a mean follow-up of 55.6 ± 23.1 months and a mean age at surgery of 64.3 ± 12.7 years. Forty-four percent of patients underwent conservative revision. The mean HHS significantly improved from 40.6 ± 9.4 points to the final value of 87.8 ± 10.5 points (p = .002), and the mean OHS went from 20.3 ± 3.8 points to 40.3 ± 5. points (p< .001). Patients who were treated with primary components or isolated revision stems in the second stage had a significant reduction in surgical times (p< .001). The mortality rate for all causes of death was 6.8%, the eradication rate was 89.9%, the reinfection rate was 4.7% and the reoperation rate was 7.4% without differences between conservative and non-conservative revisions. Two-stage exchange arthroplasty for total hip arthroplasty (THA) PJI is a good strategy that provides satisfactory results, high eradication rates and no further need for revision. The conservative two-stage revision in patients with adequate bone stock represents a feasible option with good results and survival rates.

Early Huntington’s disease (HD) include over-activation of dopamine D1 receptors (D1R), producing an imbalance in dopaminergic neurotransmission and cell death. To reduce D1R over-activation, we present a strategy based on targeting complexes of D1R and histamine H3 receptors (H3R). Using an HD striatal cell model and HD organotypic brain slices we found that D1R-induced cell death signaling and neuronal degeneration, are mitigated by an H3R antagonist. We demonstrate that the D1R-H3R heteromer is expressed in HD animal models at early but not late stages of HD, correlating with HD progression. In accordance, we found this target expressed in human control subjects and low-grade HD patients. Finally, treatment of HD mice with an H3R antagonist prevented cognitive and motor learning deficits, as well as the loss of heteromer expression. Taken together, our results indicate that D1R - H3R heteromers play a pivotal role in dopamine signaling and represent novel targets for treating HD.Impact StatementProgression of Huntington’s disease can be slowed by altering dopamine signalling through the Dopamine 1 receptor - Histamine 3 receptor heteromer.