Three-dimension-printed custom-made prosthetic reconstructions: from revision surgery to oncologic reconstructions

Background The use of custom-made 3D-printed prostheses for reconstruction of severe bone defects in selected cases is increasing. The aims of this study were to evaluate (1) the feasibility of surgical reconstruction with these prostheses in oncologic and non-oncologic settings and (2) the functional results, complications, and outcomes at short-term follow-up. Methods We analyzed 13 prospectively collected patients treated between June 2016 and January 2018. Diagnoses were primary bone tumour (7 patients), metastasis (3 patients), and revision of total hip arthroplasty (3 patients). Pelvis was the most frequent site of reconstruction (7 cases). Functional results were assessed with MSTS score and complications according to Henderson et al. Statistical analysis was performed using Kaplan-Meier and log-rank test curves. Results At a mean follow-up of 13.7 months (range, 6 \u2013 26 months), all patients except one were alive. Oncologic outcomes show seven patients NED (no evidence of disease), one NED after treatment of metastasis, one patient died of disease, and another one was alive with disease. Overall survival was 100% and 80% at one and two years, respectively. Seven complications occurred in five patients (38.5%). Survival to all complications was 62% at two years of follow-up. Functional outcome was good or excellent in all cases with a mean score of 80.3%. Conclusion 3D-printed custom-made prostheses represent a promising reconstructive technique in musculoskeletal oncology and challenging revision surgery. Preliminary results were satisfactory. Further studies are needed to evaluate prosthetic design, fixation methods, and stability of the implants at long-ter

Should all hip and knee prosthetic joints be aspirated prior to revision surgery?

Aims It is essential to exclude a periprosthetic joint infection (PJI) prior to revision surgery. It is recommended to routinely aspirate the joint before surgery. However, this may not be necessary in a subgroup of patients. The aim of our study was to investigate if specific clinical and implant characteristics could be identified to rule out a PJI prior to revision surgery. Methods We retrospectively evaluated clinical and implant characteristics of patients who underwent a hip or knee revision surgery between October 2015 and October 2018. Patients were diagnosed with a PJI according to the MSIS diagnostic criteria. Results A total of 156 patients were analyzed, including 107 implants that were revised because of prosthetic loosening and 49 because of mechanical failure (i.e. instability, malalignment or malpositioning). No PJI was diagnosed in the group with mechanical failure. In the prosthetic loosening group, 20 of 107 were diagnosed with a PJI (19%). Although there was a significantly lower chance of having a PJI with an implant age of > 5 years combined with a CRP < 5 mg/L, an infection was still present in 3 out of 39 cases (8%). Conclusion Implants with solely mechanical failure without signs of loosening and low inflammatory parameters probably do not require a synovial fluid aspiration. These results need to be confirmed in a larger cohort of patients. In case of prosthetic loosening, all joints need to be aspirated before surgery as no specific characteristic could be identified to rule out an infection

The influence of computer-assisted surgery on rotational, coronal and sagittal alignment in revision total knee arthroplasty

BACKGROUND: Despite good results of primary total knee arthroplasty (TKA), the number of revision total knee arthroplasties (rTKAs) is rising. Proper implant position is essential, since malposition leads to worse clinical outcome. In rTKA most anatomical landmarks have disappeared because of extensive bone loss, making it more difficult to adequately implant the knee prosthesis. In primary TKA, computer-assisted surgery (CAS) leads to better prosthetic alignment than mechanical navigation guides. Literature about the use of CAS in rTKA is scarce though, and the effect on rotational prosthetic alignment has not been investigated yet. Hence the primary objective of this study is to compare rotational prosthetic alignment when using CAS in rTKA compared to a mechanical navigation guide. Secondary objectives are to compare prosthetic alignment in the coronal and sagittal planes. It is hypothesized that CAS leads to better rotational, coronal and sagittal prosthetic alignment when used during rTKA. METHODS/DESIGN: A prospective clinical intervention study with use of a historical control group will be conducted. Forty-four patients with a minimum age of 18 to be admitted for CAS-rTKA between September 2012 and September 2015 will be included in the intervention group. Forty-four patients with a minimum age of 18 who underwent rTKA with the use of a mechanical navigation guide between January 2002 and April 2012 will form the historical control group. Both groups will be matched according to gender and type of revision prosthesis. Rotational prosthesis alignment will be evaluated using a CT-scan of the knee joint. DISCUSSION: Proper implant position is essential, since malposition leads to worse clinical outcome. Several studies show a significantly positive influence of CAS on prosthetic alignment in primary TKA, but literature about the use of CAS in rTKA is limited. The purpose of this study is thus to investigate the influence of CAS during rTKA on postoperative prosthetic alignment, compared to mechanical navigation guides. TRIAL REGISTRATION: Netherlands National Trial Register NTR351

Combined antibiotic therapy spacers either commercial or handmade are superior to monotherapy – a microbiological analysis at the second stage of revision

Background: Antibiotic-loaded spacers are often used during two-stage exchange for periprosthetic joint infections (PJIs) both for its mechanical properties and as a means of local antibiotic delivery. Purpose: The main goal of this study is to compare the efficacy of different options of antibiotic(s) in spacers concerning the rate of positive cultures at the second stage. Patients and Methods: We retrospectively evaluated two-stage exchange procedures for infected hip or knee arthroplasty performed between 2012 and 2018 in which adequate (at least four deep tissue samples) culture results in both stages were available. The type of spacer and antibiotics used, in addition to several other patient, infection and treatment-related variables, were registered and correlated to microbiological findings in the second stage. Results: Fifty-eight cases were included with a 19.0 % (11/58) overall rate of positive cultures during reimplantation. With a mean follow-up of 46 months, failure rate was significantly higher at 63.6 % (7/11) in cases with positive cultures at reimplantation compared to 4.3 % (2/47) for those with negative cultures during reimplantation ( p < 0.001). The need for additional surgeries was also significantly higher (odds ratio (OR) 122.67, confidence interval (CI) 95 % 11.30-1331.32, p < 0.001). Multivariable analysis revealed antibiotics in the spacers were the main independent prognostic risk factor associated with positive cultures at the second stage with an advantage for combined antibiotics. Monotherapy is associated with failure with an OR of 16.99. Longer time between surgeries did not have statistical significance ( p = 0.05), and previous surgical treatment for PJI, presence of difficult-to-treat microorganism(s), duration of systemic antibiotic therapy or even treatment within a dedicated septic team were not shown to be independent risk factors. Among combined antibiotic spacers, there were no significant differences between the rate of positive cultures during the second stage, comparing commercially available vancomycin/gentamicin spacers to hand-mixed vancomycin/meropenem manufactured spacers (8.3 % [2/24] vs. 15.0 % [3/20], p = 0.68). Conclusions: Results show that combined antibiotic therapy spacers are advantageous when compared to gentamicin monotherapy as they produce significantly lower rates of subsequent positive cultures during the second stage. Hand-mixed high-dose vancomycin/meropenem spacers seem to perform just as well as prefabricated commercially available vancomycin/gentamicin options. Level of Evidence: Therapeutic level III.info:eu-repo/semantics/publishedVersio

Total arthroplasty in ankylosed knees: a case series

OBJECTIVE: To present nine patients with ankylosis in their knees that were submitted to a total arthroplasty to lessen their pain and improve their functional limitation. For these patients, arthrodesis remained a possibility in the event of arthroplasty failure. INTRODUCTION: Ankylosis of the knee is a severe functional limitation that becomes worse when pain is present. Arthrodesis of the knee is a classical indication for such patients, since it resolves the pain; however, the severe functional limitation remains. METHODS: In the present study, we evaluated the clinical course of nine patients who underwent total arthroplasty of the knee, and were followed up for at least five years. RESULTS: The results demonstrate that all of the patients experienced a significant reduction in pain and some improvement in the degree of knee flexion and extension. CONCLUSION: Based on the latest follow-up, there has been no need to perform arthrodesis for any of our patients, showing that a total arthroplasty could be a option for treatment in knee ankylosis

Sonication of antibiotic-loaded cement spacers in a two-stage revision protocol for infected joint arthroplasty

Background. Culturing of the sonication fluid of removed implants has proven to be more sensitive than conventional periprosthetic tissue culture for the microbiological diagnosis of prosthetic joint infection. Since bacteria surviving on antibiotic-loaded cement spacers used in a two-stage exchange protocol for infected arthroplasties may cause the persistence of infection, in this study we asked whether the sonication also could be used to identify bacteria on antibiotic-loaded cement spacers removed at the second surgical stage during a two-stage exchange procedure to confirm whether or not the prosthetic joint infection had been eradicated. Methods. We cultured the sonication fluid of cement spacers that had been originally implanted in a two-stage exchange protocol in 21 patients (mean age, 66 years) affected by prosthetic joint infection (16 total knee prostheses and 5 hip prostheses). The cement spacers were vortexed for 30 seconds and then subjected to sonication (frequency 35–40 KHz). The resulting sonicate fluid was cultured for aerobic and anaerobic bacteria. Results. The sonication fluid culture of the removed spacer was positive in six patients (29%), with isolation of methicillin-sensible Staphylococcus Aureus (MSSA) in three cases, methicillin-resistant Staphylococcus Aureus (MRSA) in one case and Pseudomonas Aeruginosa in two cases. In three of these positive cases, the traditional culture of periprosthetic tissue was negative. Two patients with positive sonication culture of the spacer were successfully treated by early debridement of the revision prosthesis and systemic antibiotic therapy. In three patients a knee arthrodesis was planned and performed as the second surgical stage. In two of them the infection was caused by highly resistant Pseudomonas Aeruginosa. The other patient with a MSSA infection had been poorly compliant with the systemic antibiotic therapy due to her mental impairment. The patient originally affected by MRSA infection of his primary hip arthroplasty developed recurrent infection of his revision prosthesis and eventually underwent Girdlestone arthroplasty. Conclusions. The sonication culture can be used to discover any bacteria on the antibiotic-loaded cement spacer during a two-stage exchange protocol, thus permitting the adoption of timely treatment options, such as the early prosthetic debridment

Removal of well-fixed fixed femoral stems

The removal of a well-fixed prosthetic stem raises technical challenges. The objective is not only to remove the material, but also to prepare the implantation of a new prosthesis. Cemented stems are only very rarely unremovable; extraction of the cement mantle and plug raises the greatest difficulties. The main risk is cortex perforation, and a radiograph should be obtained at the slightest doubt. The removal of cementless stems carries a higher risk of fracture. Difficulties should be anticipated based on thorough familiarity with the implant design and on evaluations of implant fixation and bone stock. The intramedullary approach is usually sufficient to extract a cemented or cementless, well fixed, standard stem. Routine use of a transfemoral approach is warranted only in the following situations: revision surgery for infection, S-shaped stem, long stem, curvature or angulation of the femoral shaft, or unfeasible hip dislocation. However, the possibility that the intramedullary approach may need to be converted to a transfemoral approach should be anticipated. Thus, preoperative planning must include determination of the optimal length of a femoral osteotomy or femoral flap, should one be needed, and the surgeon must have access to all the revision implants and tools that might be needed for re-implantation. Experience with the various techniques is indispensable, as a well-performed extensive approach is associated with less morbidity than a fracture or trajectory error. There are three main techniques, which are described here: intramedullary extraction of a cementless stem, intramedullary extraction of a cemented stem, and transfemoral extraction through an extended trochanterotomy. The patients should receive detailed information on the difficulties of femoral stem removal and on the available solutions