The "hump" a new arthroscopic phenomenon guiding for reliable therapy of osteochondritis dissecans of variable stability status.

INTRODUCTION: Despite 150 years of research, there are currently no reliable morphological characteristics that can be used to differentiate between stable and unstable juvenile osteochondritis dissecans (JOCD) lesions in the knee joint. Arthroscopic probing is still the gold standard. In arthroscopic evaluation, a previously undescribed pattern of a cartilaginous convex elevation ("hump") was identified as a new feature and potential sign of JOCD in transition to instability. The aim of the study was to evaluate the clinical outcomes after surgical intervention (drilling) on the "hump". MATERIALS AND METHODS: In a retrospective case series of sixteen patients with an arthroscopically detectable "hump", the analysis of clinical function scores (Lysholm, Tegner) and morphological MRI monitoring of radiological healing were performed. The assessment of lesion healing was based on pre- and postoperative MRI examinations. The "hump" was defined as an arthroscopically impressive protrusion of the femoral articular surface with a minimally softened, discolored, but intact cartilage margin that, is not mobile upon in the arthroscopic palpation hook test. The primary therapy of choice was drilling of all "humps". RESULTS: The "hump" could be detected arthroscopically in 16 of 59 JOCD lesions. Specific MRI correlations with the "hump" or arthroscopic unstable lesions could not be detected. Not all "humps" showed signs of MRI-based healing after the drilling, and in some a dissection of the osteochondral flap occurred within the first postoperative year. As a result, secondary refixation became necessary. CONCLUSION: In the present study, the "hump" was identified as an important differential diagnostic arthroscopic feature of an arthroscopically primarily stable JOCD lesion, potentially placing the lesion at risk of secondary loosening over time. Therefore, drilling alone may not be appropriate in the event of arthroscopic "hump" discovery, but additional fixation may be required to achieve the healing of the lesion. LEVEL OF EVIDENCE: III.

[Ligamentous knee injuries in children and adolescents]. / Ligamentäre Kniegelenkverletzungen im Wachstumsalter.

Due to an increase in sporting activities, the number of injuries of the immature knee is continuously increasing. These injuries necessitate a special approach regarding the particular anatomical situation with open growth plates. Three of the most commonly occurring injuries are rupture of the anterior cruciate ligament, patella dislocation and meniscus injuries. The clinical results for conservative treatment of ruptures of the anterior cruciate ligament in the growth phase are inferior to operative treatment. Transepiphyseal reconstruction has been shown to be a safe treatment method and provides good clinical results. Therapy of patella instability in children has shown poor results and new surgical techniques have been introduced to perform an anatomical reconstruction of the medial patellofemoral ligament as well as to improve distal alignment. Isolated injuries to the meniscus are rare and discoid meniscus is a special phenomenon occurring in infancy. Meniscus injuries should be treated with primary sutures rather than resection. A discoid meniscus should be resected with extreme caution and anatomically reconstructed.

The development of the collagen fibre network in tissue-engineered cartilage constructs in vivo. Engineered cartilage reorganises fibre network.

For long term durability of tissue-engineered cartilage implanted in vivo, the development of the collagen fibre network orientation is essential as well as the distribution of collagen, since expanded chondrocytes are known to synthesise collagen type I. Typically, these properties differ strongly between native and tissue-engineered cartilage. Nonetheless, the clinical results of a pilot study with implanted tissue-engineered cartilage in pigs were surprisingly good. The purpose of this study was therefore to analyse if the structure and composition of the artificial cartilage tissue changes in the first 52 weeks after implantation. Thus, collagen network orientation and collagen type distribution in tissue-engineered cartilage-carrier-constructs implanted in the knee joints of Göttinger minipigs for 2, 26 or 52 weeks have been further investigated by processing digitised microscopy images of histological sections. The comparison to native cartilage demonstrated that fibre orientation over the cartilage depth has a clear tendency towards native cartilage with increasing time of implantation. After 2 weeks, the collagen fibres of the superficial zone were oriented parallel to the articular surface with little anisotropy present in the middle and deep zones. Overall, fibre orientation and collagen distribution within the implants were less homogenous than in native cartilage tissue. Despite a relatively low number of specimens, the consistent observation of a continuous approximation to native tissue is very promising and suggests that it may not be necessary to engineer the perfect tissue for implantation but rather to provide an intermediate solution to help the body to heal itself.

Identification of molecular markers for articular cartilage.

OBJECTIVE: The aim of the current study was to identify molecular markers for articular cartilage (AC) that can be used as tools for the quality control of tissue engineered (TE) cartilage. DESIGN: A genome-wide expression analysis was performed using RNA isolated from articular and growth plate (GP) cartilage, both extracted from the knee joints of 6 weeks old minipigs. After confirming the specific expression for selected genes by RT-PCR, these were used as molecular markers for the quality control of TE cartilage. RESULTS: Albeit several known chondrocyte markers were expressed to a similar extent in articular and GP cartilage, our genome-wide expression analysis led us to identify genes being selectively expressed in either GP or articular chondrocytes. These findings led us to perform a RT-PCR expression analysis for the corresponding genes to demonstrate the absence of GP-specific markers in TE cartilage, while common or AC markers were expressed. CONCLUSIONS: Taken together, these results provide important novel insights into chondrocyte biology in general and AC in particular. In addition, it is reasonable to speculate, that some of the identified genes play distinct roles in the regulation of articular chondrocyte differentiation and/or function, thereby raising the possibility that they may serve as targets for non-operative therapies of osteoarthritis (OA).

[Osteoid osteoma. X-ray-controlled resection and histologic verification using a minimally invasive diamond bone-cutting system]. / Osteoidosteom. Minimal-invasive, bildwandlergesteuerte Resektion und histopathologische Diagnosesicherung mittels Diamanthohlfräsen.

BACKGROUND: In recent years, osteoid osteomas have been treated more frequently by means of percutaneous procedures. The main disadvantage in patients with suspected osteoid osteoma is the lack of histological verification. Our study presents the results that we obtained using a minimally invasive diamond bone-cutting system allowing histologic verification. MATERIALS AND METHODS: Six patients (age 10-20 years) with osteoid osteoma in the lower extremities were subjected to resection of the nidus using a minimally invasive water-cooled diamond bone-cutting system. All specimens were histologically processed and diagnosed. RESULTS: In all patients the nidus was resected successfully, and the diagnosis was histologically confirmed. The mean operating time was 22.8 min. All patients were allowed full weight-bearing immediately, and hospitalization was a maximum of 2 days. All patients were free of pain and relapse-free during the entire 2-year postoperative follow-up. CONCLUSION: In selected localizations with a clearly visible nidus, the minimally invasive diamond bone-cutting system presented here offers an alternative to the established surgical and percutaneous procedures for treating osteoid osteomas. This procedure combines the advantages of a minimally invasive technique with the option of histological verification of the diagnosis and correct nidus ablation.

Autologous chondrocyte implantation (ACI) for cartilage defects of the knee: A guideline by the working group "Clinical Tissue Regeneration" of the German Society of Orthopaedics and Trauma (DGOU).

BACKGROUND: Autologous chondrocyte implantation (ACI) is an established and well-accepted procedure for the treatment of localised full-thickness cartilage defects of the knee. METHODS: The present review of the working group "Clinical Tissue Regeneration" of the German Society of Orthopaedics and Trauma (DGOU) describes the biology and function of healthy articular cartilage, the present state of knowledge concerning therapeutic consequences of primary cartilage lesions and the suitable indication for ACI. RESULTS: Based on best available scientific evidence, an indication for ACI is given for symptomatic cartilage defects starting from defect sizes of more than three to four square centimetres; in the case of young and active sports patients at 2.5cm(2), while advanced degenerative joint disease needs to be considered as the most important contraindication. CONCLUSION: The present review gives a concise overview on important scientific background and the results of clinical studies and discusses the advantages and disadvantages of ACI. LEVEL OF EVIDENCE: Non-systematic Review.

Biomechanical modelling of impact-related fracture characteristics and injury patterns of the cervical spine associated with riding accidents.

BACKGROUND: Horse-related injuries are manifold and can involve the upper and lower limbs, the trunk, spine or head. Cervical spine injuries are not among the most common injuries. However, they can be fatal and often result in neurological symptoms. This study investigated the influence of the posture of the cervical spine on the ultimate strength and the pattern of vertebrae failure with the aim to provide some guidance for protective clothing design. METHODS: Eighteen human cervical spines, each divided into two specimens (three vertebrae each), were subjected to a simulator test designed to mimic a spinal trauma in different postures of the specimen (neutral, flexion, extension). The stress-to-failure, the deformation at the time of fracture and the fracture patterns assessed based on CT scans were analysed. FINDINGS: Stress-to-failure of the superior specimens was lower for the flexion group compared to the others (P=0.027). The superior specimens demonstrated higher stress-to-failure in comparison to the inferior specimens (P<0.001). Compression in a neutral or flexed position generated mild or moderate fracture patterns. On the contrary, the placement of the spine in extension resulted in severe fractures mostly associated with narrowing of the spinal canal. INTERPRETATION: The results imply that a neutral cervical spine position during an impaction can be beneficial. In this position, the failure loads are high, and even if a vertebral fracture occurs, the generated injury patterns are expected to be mild or moderate.

Solubility behaviour of synthetic hydroxyapatites in aqueous solution: influence of amorphous constituents on pH value.

Some hydroxyapatites show a considerable increase of pH in aqueous solution. Rinsing experiments were performed on two commercial samples, and the pH value was plotted as a function of time. The plots lead to the conclusion that a soluble amorphous phase is responsible for the increase in pH. This investigation was supported by X-ray diffraction, microscopy and chemical analyses.

[The relation of computed tomography-determined mineral content and the fracture behavior of healthy and metastatic vertebral bodies]. / Beziehungen zwischen dem computertomographisch bestimmten Mineralgehalt und dem Frakturverhalten von gesunden und metastatischen Wirbelkörpern.

The mineral content of 42 normal and 19 vertebrae with metastases obtained at postmortem was determined by a dual energy method and this was related to their ability to fracture. In the normal vertebrae, this relationship was expressed in the form of a logarithmic function. Amongst vertebrae with osteolytic lesions, liability to fracture increased more rapidly than mineral loss. Vertebrae with osteoblastic metastases showed increased mineral concentration with an increased liability to fracture as compared with normal vertebrae.

[Child abuse--a surgical analysis]. / Kindesmisshandlung--Eine chirurgische Analyse.

Non-accidental injuries are frequently treated by surgeons without the real reason behind the trauma being identified: The differential diagnosis of child abuse would not be considered in this circumstance. This report gives hints as to the different aspects of this complex type of injury. With our case unusual (atypical) injury patterns have been shown and the diagnostic and therapeutic procedures with child abuse explained from a surgical point of view. It is of central importance to check, whether the trauma history according to the accompanying adults for the actual surgical type of injury is plausible. Incongruencies here must lead to search for further signs of trauma or its residues. When treating these children the surgeon is therefore in a key position especially to prevent future abuse, bearing in mind the special relevance of its striking high recidivation frequency.

[Carpo-metacarpal dislocation injuries]. / Karpometakarpale Luxationsverletzungen.

Carpometacarpal dislocations are rare. In most cases, the dislocation is caused by a violent injury, e.g. the crash of a motorcyclist or a fall from great height. A considerable swelling of the back of the hand may mask the characteristic lump at the root of the hand. The diagnosis can be easily missed due to serious associated injuries. The lesion is also often overlooked in the routine X-ray diagnostic. Lateral and oblique views are important for the recognition of the true extent of the lesion. Anatomical reposition is difficult if the dislocation is not fresh and open reposition is necessary. Between 1990 and 1999, altogether 16 patients who had suffered a carpometacarpal dislocation were treated. One patient had a rare dislocation of the III. to V. joints. Simultaneous dislocation of all five carpometacarpal joints was seen in three cases. The treatment mostly consists of closed reduction and temporary Kirschner wire transfixation. Fourteen patients were controlled (clinical examination and X-ray control) after an average follow-up time of three years. In addition, the DASH questionnaire was used. After an average time of 3 years the patients showed in 64% of the cases excellent and good results (eight excellent, one good). The subjective function of the hand was moderate in 29% (four patients), in one patient the subjective function was poor (7%). Five patients had a diminished range of motion of the hand. The average points in the DASH questionnaire were 24. We recommend as therapy of choice after primary closed repositioning, primary surgery by means of short Kirschner wires introduced from distal-dorsal to proximal-palmar. In cases of impossible closed reduction or in cases with local additional injuries, open treatment for fixation, is indicated.

[Autologous chondrocyte implantation (ACI) for cartilage defects of the knee: a guideline by the working group "Tissue Regeneration" of the German Society of Orthopaedic Surgery and Traumatology (DGOU)]. / Stellenwert der autologen Chondrozytentransplantation (ACT) in der Behandlung von Knorpelschäden des Kniegelenks - Empfehlungen der AG Klinische Geweberegeneration der DGOU.

Autologous chondrocyte transplantation/implantation (ACT/ACI) is an established and recognised procedure for the treatment of localised full-thickness cartilage defects of the knee. The present review of the working group "Clinical Tissue Regeneration" of the German Society of Orthopaedics and Traumatology (DGOU) describes the biology and function of healthy articular cartilage, the present state of knowledge concerning potential consequences of primary cartilage lesions and the suitable indication for ACI. Based on current evidence, an indication for ACI is given for symptomatic cartilage defects starting from defect sizes of more than 3-4 cm2; in the case of young and active sports patients at 2.5 cm2. Advanced degenerative joint disease is the single most important contraindication. The review gives a concise overview on important scientific background, the results of clinical studies and discusses advantages and disadvantages of ACI.

[The question of safety in horse-riding sports]. / Zur Frage der Sicherheit im Reitsport.

INTRODUCTION: To reduce the number of equine-related injuries, knowledge about causes of accidents is of great importance. In the present study the causes of equine-related accidents were evaluated by a questionnaire survey. Based on our results options for prevention of equine-related accidents were formulated. MATERIAL AND METHODS: The working-group "safer riding, Hamburg" and the "German riding association (FN)" created a questionnaire to evaluate causes of equine-related accidents. This questionnaire was published in the print media "Cavallo" and "St. Georg" as well as on the online portal www.hamburger-ag-reitersicherheit.de. The questionnaire was intended for all equestrians who had suffered a horse-riding accident in the past. RESULTS: 371 female and 18 male equestrians returned a completed questionnaire. At the time of the accident the average age of the casualties was 32.5 years (range: 5 - 68 years). 86 % of the casualties wore a helmet while only 14 % used a body protector. 61 % of the equestrians were amateur riders and 66 % of the accidents occurred during leisure riding. 44 % of the horses were professional sport horses. 83 % of the equestrians had known the horse for over 6 months at time of injury. DISCUSSION: The qualification of the horse as well as the familiarity between rider and horse do not seem to have an effect of reducing of the number of accidents in equestrian activities. On the other hand a good education of the rider can contribute to decrease the accident rate. While the employment of helmets in riding sports has increased in recent years the use of preventive measures such as body protectors and safety education programmes are being used too rarely.

[Spine injuries due to horse riding accidents - an analysis of 30 cases]. / Reitunfallbedingte Wirbelsäulenverletzungen - eine Analyse von 30 Fällen.

INTRODUCTION: Horseback riding entails several risk factors that predispose the participant to injury. Especially craniocerebral as well as spinal trauma were common reasons for severe injuries. Hence, it is important to use effective protective gear during riding activities. However, the protective effect of actual safety vests and helmets in case of accident is still unknown. In the present study reasons, mechanisms and patterns of equine-related spine injuries were analyzed. Based on these data the effectiveness of used protective gear during accident was assessed. MATERIAL AND METHODS: 30 equestrians took part in a questionnaire survey. Based on these answered questionnaires reasons, mechanisms and patterns of equine-related injuries as well as used protective gear during accident were evaluated and analyzed. RESULTS: 24 patients (80 %) were female and 6 (20 %) were male. The median age at the time of injury was 36 years (range 14 - 72 years). The causalities suffered from 18 fractures (60 %) and 11 discoligamentous injuries (37 %), in one case a bone-bruise-injury (3 %) was found. 7 equestrians (23 %) wore a safety vest at time of injury. DISCUSSION: Despite wearing a safety vest, the spine can get damaged when accident occurred. It is not possible to create vests for equestrians capable of protecting against all spine injuries in all accidents. If the energy impact is too high, serious injuries can result, even though protective body gear is worn. But the development of improved safety vests is necessary to reduce the number of severe spine injury in the future.

[Technological aspects of regenerative medicine and tissue engineering of articular cartilage]. / Technische Aspekte in regenerativer Medizin und Tissue Engineering von hyalinem Gelenkknorpel.

The main problem in the treatment of orthopaedic joint-surface defects will be solved by tissue engineering of cartilage implants. Entire biological osteochondral implants can be grown from autologous cells of the patient. The nutrition of articular cartilage is by diffusion only. Therefore the chondrocyte as the unique cell type is perfectly dedicated to the tissue culture approach. Engineering techniques of bioreactors are prerequisite for these biological and medical solutions. With our tissue engineering project for the generation of osteochondral constructs we demonstrate possibilities and characteristics of bioreactors for the modification of cell culture techniques and mechanical conditioning of cartilage tissue for fully operable implants.

[Risks in sport riding - a critical survey of safety standards in sport riding]. / Risikosport Reiten - eine kritische Darstellung der Sicherheitsstandards im Reitsport.

INTRODUCTION: Equitation is associated with a high rate of injuries and lethal accidents. The head is the most frequently concerned body part. Hence in the majority of the cases deaths results from head injuries. In this study injuries as well as causes of deaths were analyzed in 21 cases. Actual safety standards in equitation were appraised and suggestions for improvement were formulated. MATERIAL AND METHODS: Between 1996 and 2008 21 equestrians suffered from a fatal accident in the greater area of Hamburg. In a retrospective analysis, equestrians' records which bases on the documentation of the institute of forensic medicine as well as the insurance company ARAG were reviewed. Details of the accidents were reconstructed and pattern of injuries of those wearing a riding helmet were analyzed. RESULTS: The 21 equestrians had 29 injuries. Therefrom 86 % (18 / 21) suffered from head injuries which consequences were the causes for death. In 5 cases (24 %) equestrians wore riding helmets on the date of accident. Therefrom 80 % (4 / 5) suffered from head injuries which results in death. DISCUSSION: Actual safety standards in equitation are disappointing. The implementation of the obligation wearing a helmet as well as the improvement of the efficiency of protective clothing for equestrians is essential. Prospective studies in order to broad the state of knowledge in this context are necessary.

Long term results after implantation of tissue engineered cartilage for the treatment of osteochondral lesions in a minipig model.

In present study we determined the long term in vivo integration and histological modeling of an in vitro engineered cartilage construct. Tissue engineered autologous cartilagenous tissue was cultured on calcium phosphate cylinders and implanted into osteochondral defects into the femoral condyles in minipigs. Radiological follow-up was performed at 2, 8, 26 and 52 weeks, condyles were harvested 26 and 52 weeks post-implantation. Thickness of cultivated tissue (1.10 +/- 0.55 mm) was comparable to in situ cartilage and cells produced in vitro cartilage specific proteins. In vivo, 26 and 52 weeks post-implantation defects were resurfaced with hyaline-like tissue, the implants were well integrated with no gap at the interface between the engineered neocartilage and the adjacent articular cartilage. Synthesis of type II collagen was detected 26 and 52 weeks after implantation. The modified ICRS score increased from 26 to 52 weeks. Histomorphometric evaluation revealed a decrease in cellularity in tissue engineered cartilage from 2.2-fold of native cartilage after 26 weeks to 1.5-fold after 52 weeks. In conclusion, these findings demonstrate the integration and maturation of tissue engineered cartilage pellets attached on a bone substitute carrier implanted in osteochondral defects over a long time.