Characteristics and outcome of 16 periprosthetic shoulder joint infections.

PURPOSE: Shoulder arthroplasties are increasingly performed, but data on periprosthetic joint infections (PJI) in this anatomical position are limited. We retrospectively investigated the characteristics and outcome of shoulder PJI after primary arthroplasty from 1998 to 2010 in a single centre. METHODS: Periprosthetic joint infection was defined as periprosthetic purulence, presence of sinus tract or microbial growth. A Kaplan-Meier survival method was used to estimate relapse-free survival of prosthesis. RESULTS: From 1,571 primary shoulder prostheses, we evaluated 16 patients with a PJI at different stages, i.e, early (n = 4), delayed (n = 6) and late (n = 6) infections. The median patient age was 67 (range 53-86) years, and 69 % were females. The most commonly isolated microorganism was Propionibacterium acnes in 38 % of patients (monobacterial in four and polymicrobial in two patients). In 14 of the 16 patients, surgical interventions consisting of debridement and implant retention (6 patients), exchange (7) and explantation (1) were performed. Four patients had a relapse of infection with P. acnes (n = 3) or Bacteroides fragilis (n = 1). The relapse-free survival of the prosthesis was 75 % (95 % confidence interval 46-90 %) after 1 and 2 years, 100 % in six patients following the treatment algorithm for hip and knee PJI and 60 % in 10 patients not followed up. All but one of the relapses were previously treated without exchange of the prosthesis. CONCLUSIONS: As recommended for hip and knee PJI, we suggest treating shoulder PJI with a low-grade infection by microorganisms such as P. acnes with an exchange of the prosthesis. Cohort studies are needed to verify our results.

Development of a score set to measure function and quality of life in patients suffering from elbow pathology.

INTRODUCTION: Daily function plays an important role in the quality of life for patients suffering from pathology of the upper extremity. The recovery of functions of daily living determines the success or failure of the treatment for the patient. The goal of this study was to establish and validate a score set measuring quality of life, and objective and subjective function in general elbow pathologies. METHODS: A literature review was performed, in order to find a patient-based elbow specific questionnaire. The score set was tested and validated in a cross-sectional setting. RESULTS: The patient-rated elbow evaluation (PREE) was chosen as the patient-based elbow specific questionnaire. For measuring general health and subjective arm function, the short form-36 mental health (SF-36 MH) and the shortened disabilities of the arm, shoulder and hand questionnaire (quick DASH) were chosen, respectively. To measure objective function, several clinical tests were implemented. The score set was tested in 66 patients, of which 56.1% had function restrictions due to pain. The correlation between the PREE-function and quick DASH was found to be the highest (r = 0.74*). Between the PREE and quick DASH, the correlation was good (r = 0.70*) and between the PREE-pain and quick DASH, the correlation was moderate (r = 0.58*). The lowest correlation (r = 0.18) was found between the PREE and SF-36 MH (*p < 0.01). CONCLUSION: General health, subjective and objective function can be measured in elbow pathology patients using a score set containing the SF-36 MH, quick DASH, PREE, and several clinical tests. Further testing of the score set needs to be executed in a prospective study.

DNA methylation regulates the expression of CXCL12 in rheumatoid arthritis synovial fibroblasts.

In the search for specific genes regulated by DNA methylation in rheumatoid arthritis (RA), we investigated the expression of CXCL12 in synovial fibroblasts (SFs) and the methylation status of its promoter and determined its contribution to the expression of matrix metalloproteinases (MMPs). DNA was isolated from SFs and methylation was analyzed by bisulfite sequencing and McrBC assay. CXCL12 protein was quantified by enzyme-linked immunosorbent assay before and after treatment with 5-azacytidine. RASFs were transfected with CXCR7-siRNA and stimulated with CXCL12. Expression of MMPs was analyzed by real-time PCR. Basal expression of CXCL12 was higher in RASFs than osteoarthritis (OA) SFs. 5-azacytidine demethylation increased the expression of CXCL12 and reduced the methylation of CpG nucleotides. A lower percentage of CpG methylation was found in the CXCL12 promoter of RASFs compared with OASFs. Overall, we observed a significant correlation in the mRNA expression and the CXCL12 promoter DNA methylation. Stimulation of RASFs with CXCL12 increased the expression of MMPs. CXCR7 but not CXCR4 was expressed and functional in SFs. We show here that RASFs produce more CXCL12 than OASFs due to promoter methylation changes and that stimulation with CXCL12 activates MMPs via CXCR7 in SFs. Thereby we describe an endogenously activated pathway in RASFs, which promotes joint destruction.

Key factors for a successful National Arthroplasty Register.

Since the introduction of the first National Arthroplasty Register in Sweden in 1975, many other countries have tried to adopt the successful Scandinavian system. However, not all have overcome the political and practical difficulties of establishing a working register. We have surveyed the current registries to establish the key factors required for an effective database. We have received detailed information from 15 arthroplasty registers worldwide. The legal conditions under which they operate together with the methods of collection and handling of the data differ widely, but the fulfilment of certain criteria is necessary achieve a high degree of completeness of the data to ensure the provision of statistically relevant information.

The Swiss Orthopaedic Registry.

Following the tradition of the IDES European Hip Registry inaugurated by M. E. Müller in the 1960s, the Institute for Evaluative Research in Orthopaedic Surgery at the University of Bern started a new era of data collection using internet technology (www.memdoc.org). With support of the Swiss Orthopaedic Society, the pilot of the Swiss Orthopaedic Registry was conducted, and in cooperation with different academic and non-academic centers the practicability of integrating the various data collection instruments into the daily clinical workflow was evaluated. Three different sizes of hip and knee questionnaires were compiled, covering the individual demands of the participating hospitals whereby the smaller questionnaires always represent a subset of the next larger one. Different types of data collection instruments are available: the online interface, optical mark reader paper questionnaires, and barcode sheets. Precise implant tracking is implemented by scanning the implant barcodes directly in the operating theaters and linking them to the clinical data set via a central server. In addition, radiographic information can be linked with the clinical data set. The pilot clinics suggested enhancements to the user interface and additional features for data management. Also, recommendations were made to simplify content in some instances and diversify in others. With a new software release and adapted questionnaires the Swiss Orthopaedic Registry was officially launched in Summer 2005.

Complete sequence, expression, and evolution of the hexamerin LSP-2 of Calliphora vicina.

In cyclorraphan Diptera, two different types of hemolymph proteins exist which belong to the hexamerin family. During the last larval instar, Calliphora vicina synthesizes, besides the major fraction of arylphorin, a second hexameric protein, LSP-2. Here the developmentally regulated biosynthesis of this protein was analyzed. Western blot analyses showed that LSP-2 is not present in eggs, 1st, and 2nd instar larvae, whereas it can be detected in all tissues of last instar larvae. We report the characterization of the complete cDNA sequence that encodes a LSP-2 subunit, a nascent polypeptide of 701 amino acids with a molecular mass of 83.16 kDa. By Northern blotting, a mRNA of about 2.2 kb coding for LSP-2 is identified exclusively in the fat body of 3rd larval instars reflecting the stage and tissue specificity of LSP-2 gene expression. Phylogenetic analysis demonstrates the existence of two distinct groups of hexamerins in Diptera.

Outcome measures and their measurement properties for trapeziometacarpal osteoarthritis: a systematic literature review.

The objective was to identify all outcome measures used in studies on trapeziometacarpal osteoarthritis (TMC OA) and evaluate their measurement properties. In a two-step systematic literature review, we first identified studies including TMC OA patients and extracted all outcome measures. They were categorized according to the Outcome Measures in Rheumatology (OMERACT) core set for OA including five dimensions: pain, physical function, global assessment, imaging, and quality of life (QoL). Secondly, we retrieved articles on the measurement properties of the identified outcome measures for TMC OA patients. First, 316 articles including 101 different outcome measures were identified, addressing the OMERACT pain and function domains most frequently but under-representing QoL. Second, 12 articles investigating measurement properties of 12 outcome measures were identified. The methodological quality of these studies was poor to fair, implying that based on the literature no recommendations to use any of the outcome measures can yet be made.

Characteristics and outcome of 27 elbow periprosthetic joint infections: results from a 14-year cohort study of 358 elbow prostheses.

Elbow arthroplasty is increasingly performed in patients with rheumatic and post-traumatic arthritis. Data on elbow periprosthetic joint infection (PJI) are limited. We investigated the characteristics and outcome of elbow PJI in a 14-year cohort of total elbow arthroplasties in a single centre. Elbow prosthesis, which were implanted between 1994 and 2007 at Schulthess Clinic in Zurich, were retrospectively screened for infection. PJI was defined as periprosthetic purulence, the presence of sinus tract or microbial growth. A Kaplan-Meier survival method and Cox proportional hazard analysis were performed. Of 358 elbow prostheses, PJI was identified in 27 (7.5%). The median patient age (range) was 61 (39-82) years; 63% were females. Seventeen patients (63%) had a rheumatic disorder and ten (37%) had osteoarthritis. Debridement and implant retention was performed in 78%, followed by exchange or removal of the prosthesis (15%) or no surgery (7%).The relapse-free survival (95% CI) was 79% (63-95%) after 1 year and 65% (45-85%) after 2 years. The outcome after 2 years was significantly better when patients were treated according to the algorithm compared to patients who were not (100% vs. 33%, p <0.05). In 21 patients treated with debridement and retention, the cure rate was also higher when the algorithm was followed (100% vs. 11%, p <0.05). The findings of the present study suggest that the treatment algorithm developed for hip and knee PJI can be applied to elbow PJI. With proper patient selection and antimicrobial therapy, debridement and retention of the elbow prosthesis is associated with good treatment outcome.

[Medium-term results after m. vastus medialis obliquus-plasty for lateral patellar dislocation]. / Mittelfristige Ergebnisse der Vastus-medialis-obliquus-Plastik bei lateraler Patellaluxation.

Progressive retropatellar arthrosis is often seen in dated rigid distal realignment (i.e. osteotomy of tuberositas) at long-term follow-ups. Therefore, operations for lateral dislocation of the patella are still discussed controversially. Dynamic, proximal realignments seem to have lower rates of arthrosis but higher rates of redislocation. Recently, in anatomic and biomechanic studies, the m. vastus medialis obliquus (vmo) was found to be one of the most important proximal restraints to lateral dislocation of the patella.A total of 28 patients (mean age 21.5 years) were treated between 1994 and 2003 with a plasty of the vmo for lateral patellar dislocation. The technique was performed for most etiologies of femoropatellar instability. For this proximal soft tissue technique, the muscle tendon is detached from its patellar insertion. Subsequently, the tendon is reinserted at the patella 10-15 mm more distally and fixed with Mitek anchors. Full weight bearing in extension is possible immediately after surgery. An active vastus medialis training is started after 6 weeks. Of the patients, 27 were evaluated clinically and radiologically in 2004 (a mean of 5 years postoperatively). A total of 83% of the patients estimated the result to be good or excellent, 10% were satisfied and 7% were discontent. The mean Lysholm-Knee-Score was 83.1 points. Two patients suffered a patella redislocation (7%). A statistically significant improvement of the congruence angle was noted in the radiographs, even in medium-term controls. In 89% of the cases no or only little retropatellar arthrosis was observed. These 5 year results are comparable to those of other techniques for distal or proximal realignments. The rate of redislocation was below average. Compared to the rate of retropatellar arthrosis in long-term results of rigid distal realignment, our patients demonstrated a relative low rate after 5 years. We attribute this to the minimal interference in physiological joint mechanics and to the restored anatomy. In terms of future long-term results, our findings are promising. The idea of a proximal dynamic stabilization and the causal operative approach at the origin of pathology using vmo-plasty was confirmed in recent anatomic and biomechanic studies. Over or under correction of soft tissues could be adapted. More rigid techniques of distal realignment do not allow an adaptation to this extent and can lead to prearthrotic hyperpression in the medial femoropatellar and femorotibial joints.