Establishment of a reliable in-vivo model of implant-associated infection to investigate innovative treatment options.

The increasing number of implant-associated infections and of multiresistant pathogens is a major problem in the daily routine. In the field of osteomyelitis, it is difficult to manage a valid clinical study because of multiple influencing factors. Therefore, models of osteomyelitis with a simulation of the pathophysiology to evaluate treatment options for implant-associated infections are necessary. The aim of this study is to develop a standardized and reproducible osteomyelitis model in-vivo to improve treatment options. This study analyses the influence of a post-infectious implant exchange one week after infection and the infection progress afterward in combination with a systemic versus a local antibiotic treatment in-vivo. Therefore, the implant exchange, the exchange to a local drug-delivery system with gentamicin, and the implant removal are examined. Furthermore, the influence of an additional systemic antibiotic therapy is evaluated. An in-vivo model concerning the implant exchange is established that analyzes clinic, radiologic, microbiologic, histologic, and immunohistochemical diagnostics to obtain detailed evaluation and clinical reproducibility. Our study shows a clear advantage of the combined local and systemic antibiotic treatment in contrast to the implant removal and to a non-combined antibiotic therapy. Group genta/syst. showed the lowest infection rate with a percentage of 62.5% concerning microbiologic analysis, which is in accordance with the immunohistochemical, cytochemical, histologic, and radiologic analysis. Our in-vivo rat model has shown valid and reproducible results, which will lead to further investigations regarding treatment options and influencing factors concerning the therapy of osteomyelitis and implant-associated infections.

Union rates and functional outcome of double plating of the femur: systematic review of the literature.

BACKGROUND: The optimal treatment strategy for the surgical management of femur fractures and non-unions remains unknown. The aim of this study is to assess union rates, complications and outcome after femoral double plating. Treatment of shaft, distal, periprosthetic fractures and pathological proximal femur fractures as well as femoral non-unions with double plating were evaluated. METHODS: A systematic review according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement was conducted. Published literature reporting on the treatment and clinical outcome of femoral fractures and non-unions with double plating was identified. In total, 24 studies with 436 cases of double plating, 64 cases of single plating, 84 cases of intramedullary nailing (IM), and 1 interfragmentary screw treatment met the inclusion criteria of this systematic review. The evaluated literature was published between 1991 and 2020. RESULTS: Double plating of femoral fractures achieved high healing rates and few complications were reported. It displayed significantly less intraoperative haemorrhage, shorter surgery time reduced risk of malunion in polytraumatised patients when compared to IM. Fracture healing rate of double-plating distal femoral fractures was 88.0%. However, there were no significant differences regarding fracture healing, complication or functional outcome when compared to single plating. Treatment of periprosthetic fractures with double plating displayed high healing rates (88.5%). Double plating of non-unions achieved excellent osseous union rates (98.5%). CONCLUSIONS: The literature provides evidence for superior outcomes when using double plating in distal femoral fractures, periprosthetic fractures and femoral non-unions. Some evidence suggests that the use of double plating of femoral fractures in polytraumatised patients may be beneficial over other types of fracture fixation. LEVEL OF EVIDENCE: IV.

[Pseudarthroses of the long bones]. / Pseudarthrosen der langen Röhrenknochen.

Pseudarthrosis development is dependent on the presence of individual risk factors in approximately 10% as a result of fractures and are more frequently located in the region of the long bones. The development of non-union regularly results in prolonged pain and reduced functionality of the affected limb. The resulting clearly increased socioeconomic costs are caused by the complex operative treatment strategies and increased indirect costs, which include lost wages, social benefits and compensation. Altogether, non-unions require a differentiated therapeutic treatment strategy. The analysis of the non-union based on the diamond concept is the key for a successful planning and therapy. In this context, the use of focused, high-energy extracorporeal shock waves may be possible under specific circumstances; however, in most cases an operative revision is necessary to optimize the biomechanical stability and/or improve the local biology.

[Arthroscopic refixation of acute proximal anterior cruciate ligament rupture using suture anchors]. / Arthroskopische Refixation einer akuten proximalen vorderen Kreuzbandruptur mittels knotenlosem Fadenanker.

OBJECTIVE: Arthroscopic assisted suture anchor refixation combined with microfracturing of the femoral ACL insertion zone in cases of acute proximal anterior cruciate ligament (ACL) rupture to restore anatomical and biomechanical properties of the native ACL. INDICATIONS: Acute proximal ACL rupture/avulsion, multiligament injury of the knee CONTRAINDICATIONS: Chronic (>6 weeks) proximal ACL rupture, intraligamentary rupture, as well as previous ACL surgery. SURGICAL TECHNIQUE: Arthroscopic examination of the knee joint, debridement of the femoral insertion zone, examination of the ligament quality by a probe, insertion of a curved lasso through the ACL to place the sutures and use of a drill guide to place the anchor in the middle of the femoral ACL insertion. Microfracturing holes around the femoral footprint were made by an awl to enhance healing properties of the ACL. POSTOPERATIVE MANAGEMENT: Partial weight bearing was permitted and crutches were used for 6 weeks, knee brace limited for the first 2 weeks 0­0-0°, then 0­0-90° for the following 4 weeks. RESULTS: A total of 20 patients who underwent acute proximal ACL suture anchor refixation were evaluated after a mean follow-up of 28 months. Regarding stability, mean values of the KT-1000 arthrometer indicated stable results (<3 mm), 3 patients had a 1+ Lachman and 4 patients had a 1+ pivot shift. IKDC (International Knee Documentation Committee) score indicated that 17 cases were very good to good (12A, 4B) and in 3 cases the results were satisfactory (3C). Magnetic resonance imaging showed that the ALC was found to be intact in 17 cases. The total rate of revision was 15 % (3/20) because of recurrent instability.

Surgical treatment of acute acromioclavicular joint dislocations: hook plate versus minimally invasive reconstruction.

PURPOSE: This study was performed to compare the clinical results of a minimally invasive technique for acute acromioclavicular (AC) joint dislocation repair with the traditional hook plate fixation. METHODS: Forty-four patients with an acute (within 2 weeks after trauma) complete AC joint separation (35 male, nine female; median age 36.2 years, range 18-56) underwent surgical repair with either a minimally invasive AC joint repair or a conventional hook plate. Functional outcome was evaluated using the Constant-Murley Score (CMS), the TAFT score and the AC joint instability score (ACJI). Radiographic evaluation was performed with bilateral anterior-posterior (a.p.) stress and Alexander views. RESULTS: All patients were available after a median follow-up of 32 months (range 24-51). There were no significant differences in the mean CMS, Taft score and the ACJI between the two groups. The radiological assessment revealed no significant difference in the coracoclavicular distance. In both groups, a slight loss of reduction was observed. Periarticular ossification was seen in 11 patients of the minimally invasive AC joint repair and eight patients of the hook plate group but this did not affect the final outcome. Hook plates were removed after a median interval of 11.9 weeks (range 10-13). CONCLUSION: Good clinical results can be achieved with both minimally invasive AC joint repair and hook plate fixation. However, in the hook plate group a second operation is mandatory for plate removal. LEVEL OF EVIDENCE: III.

[Acute osteochondral lesions after patella dislocation]. / Akute osteochondrale Läsionen nach Patellaluxation.

Acute osteochondral lesions of the knee are injuries often caused by patella dislocations. In cases of negative standard x-rays magnetic resonance imaging (MRI) scans should be used to exclude these injuries, as even large fragments can escape visualization with x-rays. These lesions are strong indications for surgical intervention especially if refixation is considered. The intra-articular defect is visualized using arthroscopy and the dislocated fragment is retrieved entirely. Inspection of the fragment is performed ex situ to determine whether or not refixation should be performed. The refixation technique to be used for lesions in the femoro-patellar joint depends on fragment size and defect site. Current biodegradable implants have demonstrated good clinical results without the need for implant removal. The rehabilitation protocol should be individualized to the patient, size and site of the defect.