[Hip dislocation after revision arthroplasty : Risk assessment and treatment strategies]

With a dislocation rate of up to 35% after revision total hip arthroplasty (THA), instability is one of the major causes why this procedure fails. Independent factors for patients at risk are age, sex, and the type of revision needed. The surgical approach, implant choice, and positioning of the components are factors that the surgeon can influence to keep the dislocation rate low. Large femoral heads or double mobility (DM) cups can increase the stability of the joint. After detailed failure analysis, targeted use of different technical innovations enhances stability in revision THA and prevents further revisions.

[Cardiac post-resuscitation care. An indication for trauma whole-body CT?]

We report the case of a 51-year-old male patient who sustained a liver rupture following mechanical cardiopulmonary resuscitation (CPR) with the LUCAS® system. The patient was under anticoagulation and developed an abdominal compartment syndrome. Although the use of mechanical CPR devices, such as the LUCAS® system and the load distributing band (Autopulse®), is becoming more common, there are specific complications described in the literature, which are associated with mechanical CPR. It is important to differentiate between general complications associated with CPR and those which can be attributed to the application of mechanical CPR devices. Using the example of the presented case, this article outlines and discusses these points based on the currently available literature. It should also be noted that mechanical CPR can act in a similar way to chest trauma and can necessitate an investigation with contrast enhanced computed tomography.

[Lateral instability of the upper ankle joint]

Because of their frequency, ankle sprains are of major clinical and economic importance. The simple sprain with uneventful healing has to be distinguished from the potentially complicated sprain which is at risk of transition to chronic ankle instability. Conservative treatment is indicated for the acute, simple ankle sprain without accompanying injuries and also in cases of chronic instability. If conservative treatment fails, good results can be achieved by anatomic ligament reconstruction of the lateral ankle ligaments. Arthroscopic techniques offer the advantage of joint inspection and addressing intra-articular pathologies in combination with ligament repair. Accompanying pathologies must be adequately addressed during ligament repair to avoid persistent ankle discomfort. If syndesmotic insufficiency and tibiofibular instability are suspected, the objective should be early diagnosis with MRI and surgical repair.

[Importance of revision- and tumor-endoprosthetics in the treatment of periprosthetic fractures of the lower extremity]

Periprosthetic fractures of hip and knee prostheses are gaining clinical significance due to the increasing numbers of of primary arthroplasties. Additionally, these fractures are often associated with poor bone quality or present in patients after multiple revision procedures and concomitant excessive bone defects precluding those patients to be adequately treated by conventional osteosynthesis. Revision implants provide a wide range of options for the treatment of these fractures in order to achieve good clinical results. In the acetabular region cavitary defects associated with periprosthetic fractures can be treated by the use of megacups. Extensive segmental defects and pelvic discontinuity necessitate the use of cups with additional iliac support or even customized implants. Proximal femoral fractures can usually be fixed with modular stems and diaphyseal anchorage. Periprosthetic knee joint fractures can be treated with revision implants with modular sleeves or augment-combinations allowing sufficient bridging of bony defects. Functional reconstruction or refixation of the extensor mechanism is of crucial importance.

[Periprosthetic infections of the hip joint : Clinical approach]

BACKGROUND

Increasing rates of periprosthetic joint infections (PJI) will present orthopedic surgeons and the health care system with challenges in the next few years. New concepts in diagnostic and surgical pathways allow specialized centers to offer differentiated therapy of PJI.

AIM

This article presents an overview of recent treatment concepts for PJI of the hip emphasizing diagnosis and the clinical approach.

METHOD

A selective literature search was performed focusing on evidence-based concepts including diagnostics, surgical treatment, and biofilm active antibiotics.

RESULTS

PJI of the hip are classified as mature biofilm or immature biofilm infections. The most important step in the diagnostic procedure is to identify the pathogen and its antimicrobial susceptibility. Preoperative joint aspiration and leukocyte count, differentiation, and microbiological culture should be standard. Arthroscopic biopsy may be necessary to identify the pathogen. Depending on the biofilm maturity and the antimicrobial susceptibility, implant retention or two-stage revisions should be performed. Combination of surgical therapy and biofilm-active antibiotics are of utmost importance for successful treatment.

DISCUSSION

PJI represents a significant challenge for the orthopedic surgeon. Evidence-based and standardized clinical pathways are necessary for accurate and rapid diagnosis as well as patient-specific treatment concepts.

[Surgical technique: reconstruction of deficient extensor apparatus of the knee - a case report]

Injuries to the extensor apparatus of the knee are a rare but in case of their occurrence a serious injury. In the following discussion, the focus is on treatment of chronic patellar tendon tears. The aim of surgical treatment is the recovery of the active extension and full weight-bearing ability of the leg. The video presentation shows the operative treatment of a patient with a chronic extensor mechanism deficiency of the knee after multiple revision of a total knee arthroplasty due to periprosthetic infection and three-times occurrence of a patella tendon tear. A frame-shaped reinforcement between patella and tibial tuberosity by FiberTape® combined with a medial gastrocnemius flap was performed. This type of surgery is indicated in cases of large defects of the patellar tendon that cannot be treated with end-to-end suture or simple augmentation with autologous tendons (e.g. semitendinosus). In addition to augmentation of the tendon defect, cutaneous soft tissue defects around the knee and proximal lower leg can be covered. In general, the best treatment option is chosen according to size of the defect, the quality of the tendon tissue and possible previous surgery on the knee joint. There are no reports of large series of chronic patella tendon tears, but only isolated cases using a variety of techniques. In addition with low level of evidence, there is currently no established gold standard in the surgical treatment of insufficiencies of the extensor apparatus of the knee.

[Biopsies from bone and soft tissue sarcoma : a nationwide survey in Germany]

AIM OF THE STUDY

A biopsy is an essential step in the diagnostic cascade of malignant bone and soft tissue tumors. The objective is always the extraction of a representative tissue specimen in line with the approach for the definitive operation. The aim of this study therefore was to assess the diagnostic approaches regarding the biopsy of tumors in orthopedic centers in Germany.

MATERIAL AND METHODS

In total 60 hospitals with an orthopedic focus on tumors were contacted and provided with a newly developed questionnaire with 13 items regarding biopsy technique, indication criteria, execution, supportive imaging and histopathological results. Evaluation of the responses was performed by means of binary systems and proportional consent to every answer possibility was calculated.

RESULTS

The results of the questionnaire showed that open biopsies are performed in all centers and in 72 % of the hospitals percutaneous techniques are additionally applied. The most important criterion for an open or percutaneous procedure was the tumor location (80 %). The indications for either technique are assessed by a tumor orthopedic consultant in 68 % of the centers and special imaging is applied in 36 % of the institutions. The approach for the biopsy is defined by the orthopedic surgeon in 88 %. Percutanous biopsies are carried out by interventional radiologists in 60 % of the centers. Open biopsies are performed by residents under supervision by a tumor orthopedic consultant in 88 %. The histopathological results are discussed in 88 % of the hospitals in an interdisciplinary tumor board and in 64 % patients are informed about the diagnosis in an outpatient clinic.

CONCLUSIONS

Overall, biopsy of musculoskeletal tumors is performed according to the guidelines in most institutions. Only small differences were identified regarding the definition of the surgical approach and the application of imaging techniques during biopsy.

[Design of a high-dynamic closed-loop controlled cartilage test system]

Articular cartilage repair methods, in particular scaffold-based autologous chondrocyte implantation, are already in clinical use. In the coming years, the European guidelines on human cell-based medicinal products by the European Medical Agency (EMA) will extend today's quality control mechanisms by additional structural analyses. As articular cartilage has complex biphasic and viscoelastic mechanical properties, a high-performance material test system is required and has already been implemented. To characterize the recovery of cartilage and cartilage replacement materials, it is necessary to measure the dynamic recovery profile. A measurement system for an application like this requires an axis acceleration of more then 50 m/s(2). Furthermore, the test system needs custom-made components to fix the biological specimen while testing. A software package consisting of a graphical user interface and an axis controller leads to highly reproducible tests. The software makes use of a position and velocity controller as well as a force controller at kilohertz speed. While using the high performance force controller it is possible to apply static and dynamic loading profiles that are independent from position or speed set points and signals.

[Heterotopic ossifications in total hip arthroplasty: prophylaxis and therapy]

Heterotopic ossification (HO) is a frequent and occasionally severe complication after total hip arthroplasty. Clinical symptoms of this benign abnormal bone formation are loss of mobility and local pain. The etiology and pathomechanisms are not yet completely understood. Overexpression of bone morphogenetic proteins and dysregulation of prostaglandin metabolism seem to be relevant. Medication with non-steroidal anti-inflammatory drugs (NSAIDs) and perioperative single dose radiotherapy are used for prophylaxis, whereby radiotherapy should only be performed in patients with a history of HO or additionally after resection of HO. From currently available data selective cyclooxygenase-2 inhibitors seem to have a preventive efficacy equal to the classical NSAIDs diclofenac and indometacin. This work discusses current knowledge about the pathophysiology, risk factors and the clinical approach for prevention and treatment of HO.