The use of rotating hinge (RH) prostheses for severe primary as well as revision arthroplasty is widely established. Aim of this study was to investigate long term results of a new RH prosthesis (EnduRo®, B Braun, Germany), which uses carbon-fiber reinforced poly-ether-ether-ketone (CFR PEEK) as a new bearing material, first time used in knee arthroplasty.

Fifty-six consecutive patients, who received the EnduRo® RH prosthesis were included in this prospective study: 21 patients (37.5%) received the prosthesis as a primary total knee arthroplasty (TKA) and 35 patients (62.5%) underwent revision total knee arthroplasties (rTKA). Clinical and radiographic examinations were performed preoperatively as well as postoperatively after 3 and 12 months and annually thereafter. Min. Follow up was 7 and mean follow up 9,3 years. Clinical examination included Knee Society Score (KSS), Western Ontario and McMaster Osteoarthritis Index (WOMAC), Oxford Knee Score (OKS), and range of motion (ROM). Competing risk analysis was assessed for survival with respect to indication and failure mode.

KSS, WOMAC, OKS, and ROM significantly improved from the preoperative to the follow up investigations (p < 0.0001). There was no difference in clinical outcome between the primary and the revision group. The overall cumulative incidence for revision for any reason was 23.6% and the cumulative incidence for complications associated with failure of the prothesis was 5.6% at 7 years, respectively. Complications occurred more frequently in the revision group (p = 0.002).

The evaluated RH prosthesis provided reliable and durable results with a minimum follow-up of 7 years. Prosthesis survival was successful considering the complexity of cases. The use of this RH system in primary patients showed high survival rates. Long-term functional and clinical results proved to be satisfying in both revision and primary cases. No adverse events were associated with the new bearing material CFR-PEEK.

Ten to twenty percent of patients are dissatisfied with the clinical result after total knee arthroplasty (TKA). Aim of this study was to investigate the impact of personality traits on patient satisfaction and subjective outcome of TKA.

We investigated 80 patients with 86 computer navigated TKAs (Emotion®, B Braun Aesculap) and asked for patient satisfaction. We divided patients into two groups (satisfied or dissatisfied). 12 personality traits were tested by an independent psychologist, using the Freiburg Personality Inventory (FPI-R). Postoperative examination included Knee Society Score (KSS), Western Ontario and McMaster University Osteoarthritis Index (WOMAC) and the Visual Analogue Scale (VAS). Radiologic investigation was done in all patients.

84% of our patients were satisfied, while 16% were not satisfied with clinical outcome. The FPI-R showed statistically significant influence of four personality traits on patient satisfaction: life satisfaction (ρ = 0.006), performance orientation (ρ =0.015), somatic distress (ρ = 0.001), and emotional stability (ρ = 0.002). All clinical scores (VAS, WOMAC, and KSS) showed significant better results in the satisfied patient group. Radiological examination showed optimal alignment of all TKAs. There were no complications requiring revision surgery in both groups.

The results of our study show that personality traits may influence patient satisfaction and clinical outcome after TKA. Thus, patients personality traits may be a useful predictive factor for postoperative satisfaction after TKA.

Aim

Although established serum inflammatory biomarkers, such as serum C-reactive protein (CRP) and serum white blood cell count (WBC), showed low accuracies in the literature, they are still commonly used in diagnosing periprosthetic joint infections (PJI). For a sufficient preoperative diagnosis novel more accurate serum parameters are needed. The aim of our study was to evaluate the performances of the established and novel routinely available serum parameters in diagnosing periprosthetic joint infections when using the proposed European Bone and Joint Infection Society (pEBJIS) criteria.

Aims

Second-generation metal-on-metal (MoM) articulations in total hip arthroplasty (THA) were introduced in order to reduce wear-related complications. The current study reports on the serum cobalt levels and the clinical outcome at a minimum of 20 years following THA with a MoM (Metasul) or a ceramic-on-polyethylene (CoP) bearing.

Material and Methods

In a prospective randomized study of two groups of 65 patients each, we compared the acetabular component position when usingthe imageless navigation system compared to the freehand conventional technique for cementless total hip arthroplasty. The position of the component was determined postoperatively on computed tomographic scans of the pelvis.

Introduction

In a recent study we evaluated the clinical and radiographic long-term results as well as the serum metal concentrations of 105 cementless primary total hip prosthesis, performed between November 1992 and May 1994 with a 28-mm high-carbide-concentration metal-on-metal articulating surfaces. Forty-one patients who had had a total of forty-four arthroplasties were available for follow-up evaluation at a minimum of seventeen years postoperatively.

The median serum cobalt concentration of the patients with their hip replacement as the only source of cobalt was 0.7 µg/L (range 0.4–5.1µg/L), showing no significant difference to the previous study after a minimum of 10 years follow-up. We were investigating the systemic dissemination, which in turn, did not show more severe effects, such as carcinogenicity or renal failure. There are many complex issues associated with the analysis of metal ions, including collecting technique, analysis and reporting of the results. At the AAOS in March 2013, the Hip Society mentioned, that systemic ion levels are just one factor in the evaluation and should not be relied upon solely to determine the need for revision surgery. Furthermore, the correlation between cobalt or chromium serum, urin or synovial fluid levels and adverse local tissue reactions is incompletely understood.

Objectives: Microbial biofilms protect planctonic bacteria growing on the implants surfaces from detection and antibiotic treatment. To investigate the efficacy of sonication cultures in our patients with prosthetic joint infections we compared our findings with the results to those of periprosthetic tissue cultures and histology.

Methods: The sonication cultures of the explanted prosthesis were cultured according to the protocol by Trampuz et al. in the New England Journal of Medicin and using the routine method incubating the aspirated pus and periprosthetic material in brain-heart-infusion broth without sonication. To assess the most frequently affected component of the prosthesis all components were “sono-cultured” separately. The diagnosis of infection was based on the presence of bacteria or leucocytes in pus or tissue plus local signs and symptoms and/or systemic markers of inflammation (fever, leucocytosis, increased C-reactive protein)

Results: We investigated 60 patients with 40 septically and 20 aseptically explanted components of total knee (n=24), hip (n=21) tumor (n=6) and shoulder (n=2) endoprosthesis, as well as osteosynthetic material (n=6) and spinal instrumentation (n=1). The most frequently affected component of the hip prosthesis was the femoral head (100%) and the inlay (88%), of the knee prosthesis was the Patella (58%) and the tibia plateau (56%), of the tumor prosthesis were the polyethylene components (100%), of the shoulder prosthesis was the sphere and stem (each 100%), of the osteosynthesis material were the plate and screws (each 33%) and of the spine instrumentation were the rod and the screws (each 100%). From all detected pathogens in sonication cultures the most frequently were Staphylococcus aureus (25%), Staphylococcus epidermidis (22%) and Streptococci (13%). The sensitivity of sonication cultures and periprosthetic tissue cultures was 85% and 78% without preoperative antibiotic therapy compared with histological analysis of 100% sensitivity. The specificity was 89% for sonication cultures, 95% for periprosthetic tissue cultures and 100% for histological analysis.

Conclusion: Our results of separating the explanted components for sonication culture proved the detection of valid pathogens for every kind of endoprosthesis or implants and supplied further information for the focus of infection.

Background: We present a prospective two to ten year follow-up of soft tissue balancing surgery at the subluxated second MTP joint. The purpose of this study was to find out the effect of soft tissue balancing techniques of the second MTP joint on long term VAS and AOFAS results. As second hypotheses we compared the results of two different techniques, one group with additional transarticular Kirschner wire (KW) fixation of the second MTP joint temporary for 3 weeks postoperative and the other group without.

Materials and Methods: Fifty-four patients, 45 women and nine men, with a total of 62 operative interventions were included in our follow-up evaluation. Soft tissue balancing techniques we used were capsulotomy, lengthening of the extensor tendons, incision of the collateral ligaments and intrinsic muscles with or without temporary transarticular Kirschner wire (KW) fixation.

Pre- und postoperative VAS and AOFAS scores, as well as clinical and radiological findings were analyzed. One weightbearing and one without weightbearing dorsoplantar radiograph as well as a 45 degrees rotated radiograph were done pre and postoperatively to proof the position of the second toe.

Results: The statistical calculations showed a highly significant outcome (p< 0.0001) comparing pre- to postoperative scores.

Explorative data analysis as well as chi-square tests comparing the two groups - 29 second toes with and 33 second toes without temporarily additional transarticular KW fixation of the MTP joint - showed homogeneous distribution of all scores.

Conclusion: Our evaluation showed highly significant improvement with soft tissue balancing for subluxated second MTP joint of the second metatarsal, but no benefit from additional KW fixation of the MTP joint.

Introduction: Total knee arthroplasty in obese patients remains a challenge to most surgeons. Surgical complication rates as well as perioperative morbidity are higher than total knee arthroplasty in the nonobese. The purpose of this paper is to review our experience with total knee arthroplasty in superobese patients (BMI> 50).

Methods: From 1998–2005, 84 patients underwent 148 knee arthroplasties. Sixty-four patients underwent simultaneous bilateral total knee arthroplasties and 20 patients underwent unilateral knee arthroplasties. They were compared with similar group of nonobese patients who underwent knee arthroplasties during the same time period. All patients received combined regional and general anesthesia.

Results: Mean follow-up was 3.8 years (2–7). Knee society scores improved by 36 points in the superobese (pre-op 47 to 83 post-op) and by 45 points in the non-obese (pre-op 47 to 93 post-op) (p< .05). There was a greater incidence of complications in the superobese group, namely superficial wound infections and deep vein thrombosis. There was late loosening in three tibial components and instability in two patients that required revision in the superobese group. No reoperations in the nonobese group.

Conclusion: Although total knee arthroplasty may be safely performed in the superobese, it may be complicated by infection, loosening, instability, and lower knee scores.