Hip surgery in early childhood

Congenital dysplasia of the hip after conservative treatment does not always lead to satisfactory results. Remanent hip dislocation causes severe problems for the gait and static of the vertebral column. Here surgical treatment in early childhood (open reduction, intertrochanteric osteotomy and roof plasty, may produce an essential improvement, even if for a long term arthritis may be expected. But nowadays we have satisfactory techniques of arthroplasties with wear resistant ceramic selflocking prostheses for these cases. Besides on the CDH valuable surgical methods are available also in other hip diseases in early childhood (myelodysplasia, Perthes, cerebral palsy). Indication and surgery need special experience.     

Protein expression of MMP-13, uPA, and PAI-1 in pseudocapsular and interface tissue around implants of loose artificial hip joints and in osteoarthritis

Matrix metalloproteinase 13 (MMP-13), urokinase type plasminogen activator (uPA), and plasminogen activator inhibitor type-1 (PAI-1) have been reported to be involved in aseptic loosening of artificial hip joints. This study for the first time presents the protein levels of all of these factors in synovial-like interfaces between bone and prosthesis and in pseudocapsular tissues surrounding the artificial joint in patients with aseptic loosening (n=17) measured by ELISA. No differences were observed in the antigen expression of MMP-13, uPA, and PAI-1, comparing interface and pseudocapsular tissue. Also, no significant correlation between the protein expression of these factors and years from arthroplasty to revision or to type of fixation (cemented vs. cementless) was observed. As control, MMP-13, uPA, and PAI-1 antigen levels were also determined in the synovium of patients with osteoarthritis (n=10). Yet, the antigen levels of MMP-13, uPA, and PAI-1 in tissue specimens from patients with aseptic loosening of artificial hip joints were significantly higher compared to their expression in synovial capsular tissues obtained from patients with osteoarthritis. In conclusion, this study shows that elevated protein levels of uPA, PAI-1, and MMP-13 in periprosthetic pseudocapsular and interface tissues from patients after total hip replacement due to aseptic loosening seem not to be associated with the patient outcome.     

Transcutaneous electrical stimulation and vibration of neck muscles in neglect

Four neglect patients without visual field defects, one with a lesion of the right basal ganglia and three with a right, predominantly parietal lesion, were examined with a cancellation and a copying task before, during and after neck muscle vibration, during transcutaneous electrical stimulation of neck muscles and during vibration of hand muscles on the left side. In all patients, neck muscle vibration improved task performance, while transcutaneous electrical stimulation and hand vibration had little or no effect. The present results demonstrate that the effect of neck muscle vibration cannot be explained as arousal and activation due to unspecific sensory stimulation on the contralesional side of the body. They rather argue for the assumption that the compensatory effect of neck muscle vibration on neglect is an effect induced by the predominant activation of afferent Ia nerve fibres and their specific contribution to the central representation of egocentric space.     

Causes of rearthrotomies of the knee joint

Report on 178 rearthrotomies of the knee joint in 158 patients. Most of these rearthrotomies became necessary subsequent to meniscus operations. A review of the literature shows that these are mainly persisting or recurring complaints appearing usually under the overall pattern of "irritable knee". The principal causes were found to be leftover meniscus residues; on rarer occasions degenerative meniscus regenerates were found, or other causes such as floating cartilage, damaged cartilage of the patella, and instabilities of the condyles and of the ligaments.     

Finite element analysis on the biomechanical stability of open porous titanium scaffolds for large segmental bone defects under physiological load conditions

Repairing large segmental defects in long bones caused by fracture, tumour or infection is still a challenging problem in orthopaedic surgery. Artificial materials, i.e. titanium and its alloys performed well in clinical applications, are plenary available, and can be manufactured in a wide range of scaffold designs. Although the mechanical properties are determined, studies about the biomechanical behaviour under physiological loading conditions are rare. The goal of our numerical study was to determine the suitability of open-porous titanium scaffolds to act as bone scaffolds. Hence, the mechanical stability of fourteen different scaffold designs was characterized under both axial compression and biomechanical loading within a large segmental distal femoral defect of 30 mm. This defect was stabilized with an osteosynthesis plate and physiological hip reaction forces as well as additional muscle forces were implemented to the femoral bone. Material properties of titanium scaffolds were evaluated from experimental testing. Scaffold porosity was varied between 64 and 80%. Furthermore, the amount of material was reduced up to 50%. Uniaxial compression testing revealed a structural modulus for the scaffolds between 3.5 GPa and 19.1 GPa depending on porosity and material consumption. The biomechanical testing showed defect gap alterations between 0.03 mm and 0.22 mm for the applied scaffolds and 0.09 mm for the intact bone. Our results revealed that minimizing the amount of material of the inner core has a smaller influence than increasing the porosity when the scaffolds are loaded under biomechanical loading. Furthermore, an advanced scaffold design was found acting similar as the intact bone.     

Arthroskopisch gestützte Behandlung der aseptischen Hüftkopfnekrose

Objective

Preservation of the hip joint function by treatment of the avascular necrosis of the femoral head in adults or at least avoiding progression.

Indications

Avascular necrosis of the femoral head in adults in Steinberg stages I–III. In patients with Steinberg stage IVa (subchondral collapse ≤?15% of the articular surface, depression <?2 mm) hip joint salvage therapy in early stages of femoral head collapse.

Contraindications

Manifest osteoarthritis of the hip joint. Joint infection. Relative contraindications: subchondral collapse >?15% of the articular surface or depression >?2 mm (Steinberg stage IVb and above). Persisting risk factors for a progression of avascular necrosis (e.g., alcohol abuse, chemotherapy, local irradiation, high-dose cortisone therapy) and obesity (BMI >?40).

Surgical technique

Arthroscopy of the hip joint in case of cartilage defects and/or potential collapse of the femoral head. Without collapse of the femoral head and absence of severe damage of the cartilage: core decompression using a guiding sleeve through a lateral approach (Steinberg II, III). Subsequently curettage of the necrotic area through a central drill hole and insertion of autogenic bone cylinders using an OATS harvester (Steinberg II b/c, III b/c). In Steinberg stage IVa, reconstruction of the outline of the femoral head is attempted by reduction of the impressed portion (under intraoperative fluoroscopy).

Postoperative management

Limited weight bearing (10 kg) of the operated leg for 6 weeks. In cases of large necrotic defects located directly beneath the subchondral bone (Steinberg IIIc) as well as subchondral collapse with flattening of the femoral head (Steinberg IVa) limited weight bearing (10 kg) for 12 weeks.

Results

Early results of femoral head preserving therapy in 53 patients (56 hips, consecutively treated between June 2004 and December 2009) after 33?±?20 months: success rate (no arthroplasty, no reoperation, no radiological progress associated with clinical symptoms) 86% for patients treated with Steinberg stages I–III. Failure of the head preserving therapy with concern to the mentioned criteria depending on the initial Steinberg stage: 0 (0%) for stage I, 2 (10%) for stage II, 3 (25%) for stage III, and 4 (31%) for stage IVa.     

Predictive value and reward in implicit classification learning

Learning efficacy depends on its emotional context. The contents learned and the feedback received during training tinges this context. The objective here was to investigate the influence of content and feedback on the efficacy of implicit learning and to explore using functional imaging how these factors are processed in the brain. Twenty-one participants completed 150 trials of a probabilistic classification task (predicting sun or rain based on combinations of playing cards). Smileys or frowneys were presented as feedback. In 10 of these subjects, the task was performed during functional magnetic resonance imaging. Card combinations predicting sun were remembered better than those predicting rain. Similarly, positive feedback fortified learning more than negative feedback. The presentation of smileys recruited bilateral nucleus accumbens, sensorimotor cortex, and posterior cingulum more than negative feedback did. The higher the predictive value of a card combination, the more activation was found in the lateral cerebellum. Both context and feedback influence implicit classification learning. Similar to motor skill acquisition, positive feedback during classification learning is processed in part within the sensorimotor cortex, potentially reflecting the activation of a dopaminergic projection to motor cortex (Hosp et al., 2011). Activation of the lateral cerebellum during learning of combinations with high predictive value may reflect the formation of an internal model.     

Rekonstruktion von Segmentdefekten der langen Röhrenknochen

Surgery of malignant tumors and the subsequent outcome after treatment of complicated fracture situations of long bones often result in major bone defects. In addition to bridging of defects and stabilization with allogenic implants, defect reconstruction by callus distraction with segment transport and vascularized free fibula transfer are the procedures of choice for defect reconstruction in long bones. The heterogeneity of the causes of large bone defects and specific comorbidities of the patients require a differentiated approach. The indications and characteristics of the various surgical approaches and current developments in procedures for reconstruction of large defects in long bones are presented.     

In vivo monitoring of implant osseointegration in a rabbit model using acoustic sound analysis

Implant osseointegration can currently only be assessed reliably post mortem. A novel method that relies on the principle of acoustic sound analysis was developed to enable examination of the longitudinal progress of osseointegration. The method is based on a magnetic sphere inside a hollow cylinder of the implant. By excitation using an external magnetic field, collision of the sphere inside the implant produces a sound signal. Custom‐made titanium implants equipped thusly were inserted in each lateral femoral epicondyle of 20 New Zealand White Rabbits. Two groups were investigated: Uncoated, machined surface versus antiadhesive surface; and calcium phosphate‐coated surface versus antiadhesive surface. The sound analysis was performed postoperatively and weekly. After 4 weeks, the animals were euthanized, and the axial pull‐out strengths of the implants were determined. A significant increase in the central frequency was observed for the loose implants (mean pull‐out strength 21.1 ± 16.9 N), up to 6.4 kHz over 4 weeks. In comparison, the central frequency of the osseointegrated implants (105.2 ± 25.3 N) dropped to its initial value. The presented method shows potential for monitoring the osseointegration of different implant surfaces and could considerably reduce the number of animals needed for experiments. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:606–612, 2014.     

Spondylodiscitis of the lumbar spine in a non-immunocompromised host caused by Yersinia enterocolitica O:9

Here presented is an extremely rare case of a spinal osteomyelitis (L5–S1) with epidural empyema in a non-immunocompromised 62-year-old man caused by Yersinia enterocolitica O:9. The infection occurred acutely and required immediate surgical treatment. Y. enterocolitica was cultured from the empyema fluid, wound swabs of the intervertebral disc L5–S1 and stool cultures. Following the surgical decompression and antibiotic treatment, the patient recovered completely, without neurological deficits. A review of the literature revealed only sparse cases of spondylodiscitis due to other Y. enterocolitica serogroups. To our knowledge, we report here the first case of a spondylodiscitis of the lumbar spine caused by Y. enterocolitica serovar O:9 in a non-immunocompromised patient.