[Plate-assisted bone segment transport for bone defects of the lower extremities : Possibilities and limitations of treatment]. / "Plate-assisted bone segment transport" bei Knochendefekten an der unteren Extremität : Möglichkeiten und Grenzen der Behandlung.

Large bone defects of the lower extremities are challenging for both patients and the treating orthopedic surgeons. The treatment is determined by the size and location of the defect; however, patient-specific factors, such as the soft tissue situation and the presence of systemic comorbidities must be taken into consideration in the treatment strategy. Osteodistraction is an excellent technique especially for large bone defects exceeding 3 cm; however, it is time-consuming and required external fixation prior to the development of motorized distraction nails. This article describes the procedure for the treatment of large bone defects of the lower extremities, with its possibilities and limitations, using the novel plate-assisted bone segment transport (PABST) procedure.

Critically high metal ion levels found in metal-on-metal modular hinged knee arthroplasty : a comparison of two different systems.

AIMS: This study compared the cobalt and chromium serum ion concentration of patients treated with two different metal-on-metal (MoM) hinged total knee arthroplasty (TKA) systems, as well as a titanium nitride (TiN)-coated variant. METHODS: A total of 63 patients (65 implants) were treated using either a MoM-coated (n = 29) or TiN-coated (n = 7) hinged TKA (GenuX mobile bearing, MUTARS; Implantcast, Germany) versus the BPKS (Brehm, Germany) hinged TKA (n = 27), in which the weight placed on the MoM hinge is diffused through a polyethylene (PE) inlay, reducing the direct load on the MoM hinge. Serum cobalt and chromium ion concentrations were assessed after minimum follow-up of 12 months, as well as functional outcome and quality of life. RESULTS: No differences in mean age (69 years, 40 to 86), mean age adapted Charlson Comorbidity Index (3.1 (SD 1.4)), mean BMI (29.2 kg/m2 (SD 5.8)), or number of other implants were observed between groups. Significant improvements in outcome scores and pain levels were achieved for all groups, and there was no difference in quality of life (12-Item Short-Form Health Survey questionnaire (SF-12)). Mean cobalt and chromium ion levels were significantly higher for the GenuX versus the BPKS hinged TKA (GenuX vs BPKS: cobalt: 16.3 vs 9.4 µg/l; chromium: 9.5 vs 5.2 µg/l). The TiN-coated implants did not appear to confer improvement in the metal ion levels. Metal ion concentrations above 7 µg/l were detected in 81%(29/36) of GenuX patients versus 41% (11/27) in the BPKS group. No GenuX patients had normal levels under 2 µg/l, versus 22% of BPKS patients. No significant reduction in outcome scores was observed regardless of the metal ion levels, whereas higher work-related activity was correlated with higher chromium concentrations. CONCLUSION: Hinged TKA, using MoM hinges, resulted in critically high cobalt and chromium ion concentrations. The BPKS hinged TKA showed significantly lower metal ion concentrations compared with the GenuX TKA. No benefits were observed using TiN coating. The different weightbearing mechanics might influence the wear of the component materials. Higher workloads and physical activity could influence chromium levels. Cite this article: Bone Joint J 2022;104-B(3):376-385.

Explantation, Followed by Serial Debridement Without Antibiotic Spacers and Subsequent Revision With Cementless Components, Is Associated With High Remission Rates and Low Mortality in Periprosthetic Hip Joint Infections.

BACKGROUND: In difficult-to-treat cases, it is necessary to add debridement steps in prosthesis-free interval of 2-stage exchange. We aimed to analyze the functional and clinical outcome of patients treated with a multistage exchange of total hip arthroplasty without the use of spacers, rather only cementless implants. METHODS: Between 2009 and 2018, 84 patients (mean age: 67.3 [39-90] years) suffering chronic late-onset periprosthetic joint infection (PJI) were treated using a multistage prosthesis exchange without spacers. The mean follow-up was 70 ± 45.3 [14-210] months. The treatment included prosthesis exchange and at least 1 additional revision step before a reimplantation, owing to ongoing acute infection in the prosthesis-free interval. High-efficiency antimicrobial therapy was administered in between, which was discontinued after cementless revision implantation. RESULTS: The mean number of revisions between explantation and implantation was 2.6 (1-9). The most common microorganism was Staphylococcus epidermidis (53.6%) followed by Staphylococcus aureus (16.7%) and Cutibacterium acnes (11.9%). The bacterial load was more than one bacterium per patient in 38% of cases. All patients could be treated using a cementless implant. PJI remission was achieved in 92% of cases. Overall, 9 prostheses (11%) were replaced because of an ongoing PJI or fracture. The mean modified Harrison Hip Score was 63.4 (22-88) points. No patient died. CONCLUSION: Multistage total hip arthroplasty exchange showed high remission rates and low mortality in difficult-to-treat cases. Spacer-free and multistage treatment had no negative effect on the success rate or functional outcome, consistent with the results of published 2-stage exchange studies. Implantation of an uncemented press-fit prosthesis was possible in all patients with no elevated periprosthetic fracture rate.

Septic Arthritis of Native Shoulder and Knee Joint: What Are the Differences in Bacterial Spectrum, Treatment, and Outcome?

Background: Acute native septic arthritis is a joint-threatening emergency. To date, however, no gold-standard treatment nor joint-specific treatment algorithms exist. We aimed to evaluate the etiologies, bacterial spectrum, treatments, and surgical outcomes of septic arthritis of the shoulder and knee. Methods: Seventy-one patients with septic arthritis of either the knee (n = 42) or the shoulder (n = 29) were followed over a mean period of 40 months (26-65). Data were collected according to the performed surgical procedure and pathway as well as the cause of infection, bacterial spectrum, and the Gächter classification. The prospective clinical examination included the Knee Society Score (KSS) or Constant Score (CS; shoulder group), pre- and post-operative pain, and return to previous activity. Results: Septic arthritis was caused primarily by post-interventional or post-traumatic conditions in the knee group and by hematogenous infection in the shoulder group. Staphylococcus aureus and S. epidermidis were most common, whereas Propionibacerium. were seen only in shoulder infections. Remission rates were 95% in the knee versus 90% in the shoulder group, whereas the mortality rate in the shoulder group was 10% (no one died in the knee group). While most knee infections could be managed with an arthroscopic approach, all shoulder infections necessitated an open approach. The mean KSS was 87.3 (49-100); the mean CS was 66.6 (37-95). Fifty percent of patients in the shoulder group versus 71% in the knee group reached their previous level of activity. Conclusion: The knee group exhibited post-interventional etiology, in line with high-virulence microbes and a high success rate with arthroscopic restoration. Septic shoulder arthritis showed hematogenous scattering, low-virulent microbes, and multiple interventions with a final open approach was always required. In contrast to the knee, in septic arthritis of the shoulder, a significant reduction in function has to be expected.

Procedure for single-stage implant retention for chronic periprosthetic infection using topical degradable calcium-based antibiotics.

INTRODUCTION: Surgical treatment using DAIR (debridement, systemic antibiotics, and implant retention) can lead to high rates of treatment success in cases of early periprosthetic joint infection (PJI) but can fail in late-onset cases. Supplementary local antibiotic therapy is not yet generally established and lacks evidence-based proof of efficacy. The aim of this study was to analyze DAIR outcomes in recurrent PJI cases and patients who are not suitable for a two-stage exchange, using additional degradable calcium-based antibiotics. METHODS: All patients fulfilled the Infectious Diseases Society of America (IDSA) guidelines for chronic late-onset PJI but were not suitable for a multistage procedure because of their individual operation risk. A total of 42 patients (mean age, 73 years) were treated using a single-stage algorithm consisting of DAIR, followed by implantation of degradable antibiotics chosen in accordance with an antibiogram. OSTEOSET® (admixed ceftriaxone/vancomycin/tobramycin) and Herafill-Gentamycin® were used as carrier systems. The follow-up period was 23 months (± SD, 10.3). The study is based on institutional review board (IRB) approval. RESULTS: The clinical entities were chronic PJI of the hip (45.2%), knee (28.6%), and knee arthrodesis (26.2%). The bacterial spectrum was composed of Staphylococcus epidermidis (29%), Staphylococcus aureus (21%), and Enterococcus faecalis (21%). 21.4% showed a combination of two or more bacteria. In 73.8%, permanent remission was achieved, while 11.9% showed chronic PJI under implant retention. Implant retention could be achieved in 85.7%. CONCLUSION: DAIR usually shows low levels of success in difficult-to-treat cases. However, we could demonstrate the successful treatment of patients with recurrent PJI (typically considered DAIR-inappropriate) using degradable antibiogram-based topical calcium-based antibiotics. Over 70% of the cases went to remission and over 85% of the implants could be retained.

Treatment algorithms for chronic osteomyelitis.

BACKGROUND: Osteomyelitis was described many years ago but is still incompletely understood. Its exogenously acquired form is likely to become more common as the population ages. We discuss biofilm formation as a clinically relevant pathophysiological model and present current recommendations for the treatment of osteomyelitis. METHODS: We selectively searched the PubMed and Cochrane databases for articles on the treatment of chronic osteomyelitis with local and systemic antibiotics and with surgery. The biofilm hypothesis is discussed in the light of the current literature. RESULTS: There is still no consensus on either the definition of osteomyelitis or the criteria for its diagnosis. Most of the published studies cannot be compared with one another, and there is a lack of scientific evidence to guide treatment. The therapeutic recommendations are, therefore, based on the findings of individual studies and on current textbooks. There are two approaches to treatment, with either curative or palliative intent; surgery is now the most important treatment modality in both. In addition to surgery, antibiotics must also be given, with the choice of agent determined by the sensitivity spectrum of the pathogen. CONCLUSION: Surgery combined with anti-infective chemotherapy leads to long-lasting containment of infection in 70% to 90% of cases. Suitable drugs are not yet available for the eradication of biofilm-producing bacteria.