Level III, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

This case study discusses how we diagnosed and treated a patient with a late haematogenous bilateral periprosthetic joint infection (PJI) after total knee arthroplasties caused by Ureaplasma urealyticum. This has never been reported before. We will discuss how we used a PET-CT, synovial fluid cell count, and synovial fluid analysis by 16S rRNA gene sequencing to diagnose this PJI. We will also discuss how we treated this patient to obtain full recovery.

Abstract. Introduction: Prosthetic joint infection (PJI) is a relatively uncommon (average incidence 0.5-2%) but devastating complication, with significant morbidity and leading to tremendously increased health care costs. In 2013, delegates from nine hospitals covering a large region in the South-East Netherlands composed one combined treatment protocol for acute PJI of total hip and knee arthroplasty (THA and TKA). This protocol was based on the definition of acute PJI according to Workgroup of the American Musculoskeletal Infection Society (MSIS) and the principles of debridement, antibiotics, irrigation and retention (DAIR).Methods: Patients with a THA or TKA treated with DAIR because of suspicion of PJI were selected from the online PJI database. PJI was defined as at least two phenotypically identical pathogens, isolated in cultures from at least two separate tissues, obtained from the affected prosthetic joint. Acute PJIs, occurring within 90 days after primary implantation, between January 2014 and December 2016, were analyzed. We analyzed the PJI incidence rate, patient clinical and microbiological characteristics of PJI, outcome of the DAIR treatment and adherence to the regional protocol.Results: A total of 310 primary THA or TKA with a suspected PJI were registered in the regional PJI database, 236 met the definition of acute PJI, representing overall incidence of 1.12%. Following the regional treatment protocol replacement of exchangeable parts took place in 45% in 2014 to 70% in 2016. After 12 months follow-up, prosthesis retention was achieved in 87% and 3% of the patients died within one year after the primary surgery.Conclusion: Results of the regional cohort are in line with the available literature. Regional collaboration and regular feedback on registered data resulted in better adherence to the combined treatment protocol. Despite our attempts to improve PJI care, PJI remains a serious complication of THA and TKA with a significant mortality rate and burden for the patient.

Background and purpose — The preferred treatment of an acute prosthetic joint infection (PJI) is debridement, antibiotics, irrigation and retention of the prosthesis (DAIR). The antibiotic treatment consists of an empirical and targeted phase. In the empirical phase, intravenous antibiotics are started after surgery before micro-organisms are determined in microbiological cultures. Which empirical antibiotic is used differs between hospitals, partly reflecting geographic differences in susceptibility spectrums. We investigated whether flucloxacillin should remain the antibiotic of choice in our hospital for empiric treatment of acute PJI with DAIR.Patients and methods — We retrospectively analyzed 91 patients treated for PJI with DAIR between 2012 and 2016. The susceptibility of micro-organisms was determined in multiple cultures of periprosthetic tissue and synovial fluid for 3 antibiotics: amoxicillin/clavulanic acid, cefazolin, and flucloxacillin.Results — Positive microbiological cultures from 68 patients were analyzed. Staphylococcus aureus was the predominant pathogen, cultured in half of the patients. In one-third of patients more than 1 micro-organism was found. On a patient level, the data showed that 65% were responsive to flucloxacillin, 76% to amoxicillin/clavulanic acid, and 79% to cefazolin.Interpretation — Flucloxacillin appeared to be a suboptimal choice in our patient population treated with DAIR. We therefore changed our practice to cefazolin as the preferred antibiotic in the empirical treatment of acute PJI with DAIR.

The long-term prognosis of LCPD Catterall type 2 and 3 is relatively benign. However, more than 50% of the patients will develop signs of osteoarthritis between the 4th and 5th decades. At the latest follow-up a strong increase in the number of cases with osteoarthritis was seen. Sphericity of the femoral head is an important predicting factor in the development of osteoarthritis.

Case Description: A 56-year-old man with persistent knee pain and poor physical functioning due to recurring loosening of a (revised) total knee arthroplasty, was treated with a modified Gritti-Stokes amputation. Objectives: to describe the modified Gritti-Stokes amputation technique as an ultimate therapy for failed total knee arthroplasty and to assess the functional outcome for one patient 1 year post-surgery. Study design: a single patient case study. Treatment: a modified Gritti-Stokes amputation, with removal of the overlying cartilage and subchondral surfaces of both the patella and femur after removing the total knee arthroplasty. Outcomes: After rehabilitation, the patient has a fully end-bearing residual limb, is able to walk without pain (with a prosthesis) and perform his daily activities. Conclusions: In cases of recurring loosening of a (revised) total knee arthroplasty, a modified Gritti-Stokes amputation can create an end-bearing residual limb without pain and with good functional outcome.

Purpose Despite good survival rates of revised knee prostheses, little is known about recovery trajectories within the first 12 months after surgery. This retrospective observational study explored recovery trajectories in terms of pain, function and quality of life in patients after revision knee arthroplasty over 12 months. Methods Eighty-eight revision knee arthroplasty patients rated changes in daily physical functioning using the anchor question (0: very much worsened; 7: very much improved). Patient reported outcome measures (PROMs) of pain (range 0–10), function (Oxford Knee Score) and quality of life (EQ-5D-3L) were assessed preoperatively, at 3 and 12 months postoperatively. Four recovery trajectories were identified using the anchor question at 3 and 12 months postoperatively: no improvement, late improvement, early improvement, and prolonged improvement. Repeated measures ANOVA was conducted with recovery trajectories as dependent variable and PROM assessments as independent variables. Results Sixty percent reported improvement in daily physical functioning at 12 months postoperatively. Age and reason for revision differed between groups. Pain, function and EQ-5D-3L differed between groups over time. Late and prolonged improvement groups improved on all PROMs at 12 months. The early improvement group did not report improvement in daily physical functioning at 12 months, while improvements in function and pain during activity were observed. Conclusions Different recovery trajectories seem to exist and mostly match PROMs scores over time. Not all patients may experience beneficial outcome of revision knee arthroplasty. These findings are of importance to provide appropriate information on possible recovery trajectories after revision knee arthroplasty to patients. Level of evidence III