Biomimetic sulphated alginate hydrogels suppress IL-1ß-induced inflammatory responses in human chondrocytes.

Loss of articular cartilage from ageing, injury or degenerative disease is commonly associated with inflammation, causing pain and accelerating degradation of the cartilage matrix. Sulphated glycosaminoglycans (GAGs) are involved in the regulation of immune responses in vivo, and analogous polysaccharides are currently being evaluated for tissue engineering matrices to form a biomimetic environment promoting tissue growth while suppressing inflammatory and catabolic activities. Here, we characterise physical properties of sulphated alginate (S-Alg) gels for use in cartilage engineering scaffolds, and study their anti-inflammatory effects on encapsulated chondrocytes stimulated with IL-1ß. Sulphation resulted in decreased storage modulus and increased swelling of alginate gels, whereas mixing highly sulphated alginate with unmodified alginate resulted in improved mechanical properties compared to gels from pure S-Alg. S-Alg gels showed extensive anti-inflammatory and anti-catabolic effects on encapsulated chondrocytes induced by IL-1ß. Cytokine-stimulated gene expression of pro-inflammatory markers IL-6, IL-8, COX-2 and aggrecanase ADAMTS-5 were significantly lower in the sulphated gels compared to unmodified alginate gels. Moreover, sulphation of the microenvironment suppressed the protein expression of COX-2 and NF-κB as well as the activation of NF-κB and p38-MAPK. The sulphated alginate matrices were found to interact with IL-1ß, and proposed to inhibit inflammatory induction by sequestering cytokines from their receptors. This study shows promising potential for sulphated alginates in biomimetic tissue engineering scaffolds, by reducing cytokine-mediated inflammation and providing a protective microenvironment for encapsulated cells.

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.

Quantitative 3D MRI reveals limited intra-lesional bony overgrowth at 1 year after microfracture-based cartilage repair.

OBJECTIVE: Intra-lesional bony overgrowth (BO) identified during or following cartilage repair treatment is being frequently described through subjective reports focusing primarily on incidence. Our objective was to quantify the exact volume of intra-lesional BO at 12 months post-cartilage repair treatment, to determine if a correlation exists between the extent of BO and clinical outcomes, and to visualize and characterize the BO. DESIGN: MRI scans were systematically obtained during a randomized clinical trial for cartilage repair (Stanish et al., 2013) that compared two microfracture-based treatments in 78 patients. Semi-automated morphological segmentation of pre-treatment, 1 and 12 months post-treatment scans utilizing a programmed anatomical atlas for all knee bone and cartilage structures permitted three-dimensional reconstruction, quantitative analysis, as well as qualitative characterization and artistic visualization of BO. RESULTS: Limited intra-lesional BO representing only 5.8 ± 5.7% of the original debrided cartilage lesion volume was found in 78 patients with available MRIs at 12 months. The majority (80%) of patients had very little BO (<10%). Most occurrences of BO carried either spotty (56.4%) or planar (6.4%) morphological features, and the remaining balance (37.2%) was qualitatively unobservable by eye. Pre-existing BO recurred at 12 months in the same intra-lesional location in 36% of patients. No statistical correlations were found between BO and clinical outcomes. CONCLUSIONS: Intra-lesional BO following microfracture-based treatments may not be as severe as previously believed, its incidence is partly explained by pre-existing conditions, and no relationship to clinical outcomes exists at 12 months. Morphologically, observable BO was categorized as comprising either spotty or planar bone.

[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.

Scientific Evidence Base for Cartilage Injury and Repair in the Athlete.

Soccer players and athletes in high-impact sports are frequently affected by knee injuries. Injuries to the anterior cruciate ligament and menisci are frequently observed in soccer players and may increase the risk of developing an articular cartilage lesion. In high-level athletes, the overall prevalence of knee articular cartilage lesions has been reported to be 36% to 38%. The treatment for athletic patients with articular cartilage lesions is often challenging because of the high demands placed on the repair tissue by impact sports. Cartilage defects in athletes can be treated with microfracture, osteochondral grafting, and autologous chondrocyte implantation. There is increasing scientific evidence for cartilage repair in athletes, with more extensive information available for microfracture and autologous chondrocyte implantation than for osteochondral grafting. The reported rates and times to return to sport at the preinjury level are variable in recreational players, with the best results seen in younger and high-level athletes. Better return to sport is consistently observed for all repair techniques with early cartilage repair. Besides minimizing sensorimotor deficits and addressing accompanying pathologies, the quality of the repair tissue may be a significant factor for the return to sport.

[Use of human progenitor cells in the treatment of cartilage damage]. / Klinische Behandlung von Gelenkknorpelschäden mithilfe autologer Vorläuferzellen.

Articular cartilage defects have virtually no self-healing capacity. As a consequence, a surgical approach for symptomatic grade III/IV defects is required. The application of bone marrow-stimulating techniques (Pridie drilling, microfracture) is only able to reproduce mechanically inferior fibrous cartilage tissue. The minimally invasive surgical technique and low cost with acceptable results in the medium term are the main reasons for the application of these techniques. The combination of microfracture and biomaterials, i.e., the AMIC technique, has not yet proved that the disadvantages of the marrow stimulation techniques can be overcome. At present, only laboratory cultivated autologous chondrocytes are able to restore a biomechanically superior cartilage layer. By selecting the appropriate cell fraction in conjunction with the controlled release of differentiating growth factors, sufficient cartilage regeneration also appears to be achievable on the basis of bone marrow aspirate. This is the subject of experimental studies of bone marrow aspirates and autologous growth factors with encouraging initial results.

Cartilage repair approach and treatment characteristics across the knee joint: a European survey.

INTRODUCTION: To describe indication, approach and treatment modalities for the management of knee cartilage lesions among a selected European population. METHODS: An electronic questionnaire covering general and specific items concerning cartilage repair at the knee joint was designed and disposed to survey cartilage treatment characteristics among a defined population of trained and accredited musculoskeletal surgeons. RESULTS: A total of 242 (80.13%) interviewees returned the questionnaire. Two-thirds of the respondents considered patient age to not limit (33.1%) or considered the age of 50 as the upper limit (32.2%) for interventional cartilage surgery. There was no consensus on when to correct mechanical axis deformation. Irrespective of lesion size, surgical debridement and microfracture are the techniques most frequently used. Surgical approach to full-thickness cartilage defects is commenced when the lesion size exceeds 1 cm(2) in 75.6% of respondents; mainly utilizing microfracture or debridement for defects smaller than 1, 2 and 3 cm(2). Controversy exists for treatment of lesions exceeding 3 cm(2), where autologous chondrocyte transplantation is utilized in the majority of cases (33.5%), while as well microfracture (19.0%) and with lesser frequency osteochondral plug (9.5%) transplantation are recommended. Debridement was indicated to be used in combination with other techniques, while microfracture, chondrocyte or osteochondral plug transplantation are applied as individual techniques. CONCLUSIONS: Microfracture with debridement are the two most frequently used operations in lesions up to 3 cm(2). There remains disagreement when indicating cartilage repair when age, mechanical axis deviation or treatment of lesions over 3 cm(2) are concerned.

[Current treatment for cartilage damage in the patellofemoral joint]. / Aktuelle Behandlung des Knorpelschadens im Patellofemoralgelenk.

Joint cartilage damage in adults has practically no tendency to self healing. Symptomatic grade III/IV damage requires surgical treatment. There are special challenges involved in cartilage damage in the patellofemoral joint as the complicated biomechanics of the joint is often combined with dysplasia. All tissue regeneration measures are based on the recruitment of cells. The synovial cells available in the joint can be differentiated to fibrous cartilage under certain mechanical conditions; however, they cannot sufficiently fill in defects. Also the use of bone marrow cells for cartilage reconstruction only creates mechanically inferior fibrous cartilage (Pridie drillings, microfracture, AMIC). Presently only cultivated, autologous chondrocytes from the lab are available for a biomechanically high-quality reconstruction of the cartilage layer.The application of mesenchymal stem cells is a subject of extensive international research. However, the first experimental studies, after initial formation of cartilage, disappointingly show significant ossification. Essential conditions for a successful treatment of patellofemoral cartilage damage are the diagnosis of accompanying pathological conditions, selection of the right cartilage-regenerating procedure, sufficient removal of the basic pathological defect, and implementation of standardized rehabilitation.

Marrow stimulation techniques.

Due to the very low intrinsic activity of human adult cartilage, healing of chondral and osteochondral defects in patients cannot be expected. In treating symptomatic cartilage damage, marrow stimulation methods belong to the most frequently used methods, along with autologous chondrocyte transplantation (ACT) and mosaicplasty. These arthroscopic procedures are generally easy and the marrow stimulation treatment costs relatively little. In recent years, Pridie drilling has been increasingly replaced by the microfracture technique. This modification relies on the same biological principles of promoting resurfacing with the formation of fibro-cartilaginous repair tissue. For the treatment of smaller cartilage defects (<2.5 cm(2)), microfracture still remains the first choice for treatment. The clinical results after microfracture in the knee are age dependent. Younger and active patients (<40 years) with smaller isolated traumatic lesions on the femoral condyles have the best long-term results. The deterioration of the clinical results begins after 18 months and is significantly more pronounced in older patients with defects on the patella-femoral joint and tibia. The inferior quality of the repair tissue, partially incomplete defect filling and new bone formation in the defect area seem to be limitations of these methods. The AMIC (autologous matrix induced chondrogenesis) technique was developed to enable treatment of larger defects by the application of a collagen Type III/I membrane (Geistlich Pharma, Wolhusen, Switzerland), in particular when cell-engaged procedures such as ACT cannot be used for financial reasons or because it is not indicated. AMIC seems to be particularly suitable for treating damaged retropatellar cartilage, which is an advantage because these defects can be hard to treat with standard microfracturing alone. The results of the ongoing studies are awaited to establish whether better results with this technology are achievable in the long term.

Tibial wedge osteotomy for osteochondral transplantation in talar lesions.

Between 1999 and 2002, 16 patients with osteochondral lesions on the central and posterior talar dome underwent osteochondral autografting. A new approach with temporary removal and replacement of a tibial bone block from the anterior tibial plafond was adopted. Inclusion criteria were joint stability, an age between 18 and 50 years, and osteochondral lesions stages 3 and 4 according to the radiological classification of Loomer, for which previous arthroscopic treatment was not successful. All patients underwent clinical and MRI evaluation after 12, 35 and 59 months. The AOFAS Ankle Hindfoot score improved significantly between the preoperative period and 1 year (p < 0.001), between 1 and 3 years (p < 0.001), but not between 3 and 5 years postoperative (p = 0.37). The score was independent from patients gender (p = 0.44) and age. The Spearman coefficient of correlation between clinical outcome and defect size was - 0.79 (p = 0.01), indicating that patients with small lesions had the best results. Control radiographs and MRIs showed no reduced joint space and good integration of the tibial bone block without incongruency. Osteochondral grafting with temporary removal of a tibial bone block is a successful technique with good midterm results in osteochondral talar lesions for which arthroscopic excision, curettage and drilling has failed.

Classification of graft hypertrophy after autologous chondrocyte implantation of full-thickness chondral defects in the knee.

OBJECTIVE: Graft hypertrophy is a major complication seen in autologous chondrocyte implantation (ACI) with a periosteal flap. We present the first magnetic resonance imaging (MRI) classification for periosteal hypertrophy including a grading of clinical symptoms and the surgical consequences. METHODS: One hundred and two patients with isolated chondral defects underwent an ACI covered with periosteum and were evaluated preoperatively, 6, 18 and 36 months after surgery. Exclusion criteria were meniscal pathologies, axial malpositioning and ligament instabilities. Baseline clinical scores were compared with follow-up data by paired Wilcoxon-tests for the modified Cincinnati knee, the ICRS (International Cartilage Repair Society) and a new MRI score including the parameters defect filling, subchondral edema, effusion, cartilage signal and graft hypertrophy. Hypertrophic changes were graded from 1 (minimal) to 4 (severe). RESULTS: All scores showed significant improvement (P<0.001) over the entire study period. Patients with femoral lesions had significantly better results than patients with patella lesions after 18 and 36 months postoperative (P<0.03). Periosteal hypertrophy occurred in 28% of all patients. Fifty percent of all patella implants developed hypertrophic changes. No patient with grade 1, and all patients with grade 4 hypertrophy had to undergo revision surgery. The Pearson correlation between graft hypertrophy and ICRS score was 0.78 after 6 months, and 0.69 after 36 months (P<0.01). Inclusion of graft hypertrophy in the MRI score improves the correlation to clinical scores from 0.6 to 0.69. CONCLUSIONS: Grading graft hypertrophy helps to identify patients needing an early shaving of the graft. Its integration into an MRI score improves correlation with clinical scores. Re-operation depends on the grade of hypertrophy and clinical symptoms.

[Operative treatment of cartilage lesions in the knee joint]. / Chirurgische Therapieverfahren zur Behandlung umschriebener Knorpelschäden am Kniegelenk.

With regard to the current demographic changes in today's population and the increasing demands of the patients i. e. in sports activity, the operative treatment of chondral lesions gained of importance in recent years. The treatment of cartilage injuries is not only of great importance in order to reduce the patients' symptoms, but also intends to avoid the appearance of secondary arthrosis. There are several different techniques available for the treatment of full-thickness defects (such as microfracture and autologous chondrocyte implantation), some of them following related principles. The choice of the optimal treatment technique remains of great importance and represents one of the major responsibilities of the surgeon in order to achieve optimal results. The current article represents a review of current techniques and developments in operative cartilage repair of the knee joint and gives help in the decision-making process, since the use of the appropriate technique becomes more and more important in order to achieve optimal clinical results.

Results after microfracture of full-thickness chondral defects in different compartments in the knee.

OBJECTIVE: To determine if the clinical results after microfracture of full-thickness cartilage lesions deteriorate over a period of 36 months. METHODS: Between 1999 and 2002 85 patients (mean age 39.5 years) with full-thickness cartilage lesions underwent the microfracture procedure and were evaluated preoperatively and 6, 18 and 36 months after surgery. Exclusion criteria were meniscal pathologies, axial malpositioning and ligament instabilities. Baseline clinical scores were compared with follow-up data by paired Wilcoxon-tests for the modified Cincinnati knee and the International Cartilage Repair Society (ICRS)-score. The effects of the lesion localization and Magnetic resonance imaging (MRI) parameters were evaluated using the Pearson correlation and independent samples tests. RESULTS: Both scores revealed significant improvement 18 months after microfracture (P<0.0001). Within the second 18 months after surgery there was a significant deterioration in the ICRS-score (P<0.0001). The best results could be observed in chondral lesions of the femoral condyles. Defects in other areas of the knee deteriorated between 18 and 36 months after microfracture. MRI 36 months after surgery revealed best defect filling in lesions on the femoral condyles with significant difference in the other areas (P<0.02). The Pearson coefficient of correlation between defect filling and ICRS-score was 0.84 and significant at the 0.01 level. CONCLUSIONS: Microfracture is a minimal invasive method with good short-term results in the treatment of small cartilage defects. A deterioration of the results starts 18 months after surgery and is most evident in the ICRS-score. The best prognostic factors have young patients with defects on the femoral condyles.

[Indications and implementation of recommendations of the working group "Tissue Regeneration and Tissue Substitutes" for autologous chondrocyte transplantation (ACT)]. / Indikations- und Durchführungsempfehlungen der Arbeitsgemeinschaft "Geweberegeneration und Gewebeersatz" zur Autologen Chondrozyten-Transplantation (ACT).

For the treatment of full-thickness articular cartilage lesions of the knee joint, as a result of trauma or osteochondritis dissecans, a variety of biological reconstruction techniques have been developed. Different studies, some of which were performed as randomised, prospective clinical studies, showed that the autologous chondrocyte transplantation (ACT) provides the most satisfying and reliable method of cartilage reconstruction in the adult when applied to defects exceeding 4 cm (2). Based on these results, ACT seems to be of economic benefit, as the risk of developing osteoarthritis correlates significantly with the size of the cartilage defect, when not treated properly and in time. Surveying the studies on basic scientific aspects of ACT, cartilage defect animal models and clinical studies, it can be concluded that clinical results of ACT depend on a variety of factors. In this review, published by the joined advisory board of the German Societies of Traumatology (DGU) and Orthopaedic Surgery (DGOOC), we summarize the current knowledge available and the state of the art concerning ACT. Especially we discuss the advantages of different procedures, methods for treating knee cartilage defects and factors that influence the outcome of the different treatment regimens, with the aim to develop guidelines for the correct indication and application of the ACT.

[Combinations of different cartilage resurfacing techniques]. / Kombinationen moderner knorpelrekonstruktiver Verfahren.

AIM: The aim of this work was to control the results after simultaneous use of different modern resurfacing techniques. METHODS: We examined the patients who were subjected to different cartilage repair methods using the ICRS score (anterograde drilling, autologous chondrocytes transplantation, OATS, refixation with resorbable pins, spongious bone grafting, HTO). RESULTS: In two cases the combination of different cartilage regenerative methods in a one-step technique produced a good reconstruction of the joint surface with good clinical outcome. With the implantation of carbon plaques, osteolysis of the spongious bone in combination with an incomplete defect filling can be observed. The therapy must be individual and take the clinical, radiological and intraoperative findings into consideration. CONCLUSION: The combination of different resurfacing techniques may have success only if the biomechanical properties of the joint with axial malpositioning and ligament instabilities are considered and treated as well. New prospects are offered particularly for young patients with extensive cartilage damage and without other therapeutic options.

Arthroscopic management of osteochondral lesions of the talus: results of drilling and usefulness of magnetic resonance imaging before and after treatment.

Since the advent of operative ankle arthroscopy and magnetic resonance imaging (MRI) specific treatment of osteochondritis dissecans of the talus has progressed rapidly. Drilling is still the treatment of choice in early stages of osteochondritis dissecans of the talus. Rear-entry guides and preoperative planning with MRI have led to better results with this kind of treatment. Within 5 years, 42 patients (26 male and 16 female) underwent arthroscopic treatment of osteochondritis dissecans of the talus, 22 underwent percutaneous drilling, 13 cancellous bone grafting, 4 refixation, and 3 curettage. The average age of the patients was 28 years (range, 11 to 53 years). A clinical score system was used in a clinical and MRI follow-up of 19 of the patients with K-wire drilling. Up to 100 points are given in the categories pain, stability/insecurity, efficiency/pain-free walking distance, gait, differences in circumference, range of motion, and power. There was a history of trauma in 31 of the 42 patients. The majority of lesions (24 cases) were localized at the lateral talus, and these patients all had trauma. In 11 of the 18 lesions at the medial talus, there was no evidence of trauma. The 19 patients in the follow-up achieved an average of 87 points. K-wire drilling represents the chief component of early stages with intact or partially fractured cartilage surface, whereas arthroscopically controlled cancellous bone grafts after curettage are used in grade II stages only. Results of K-wire drilling are not worse than those of cancellous bone grafts; this is attributable to a generous perforation of the sclerosis. This has contributed to an improved preoperative diagnosis with MRI.

The operative treatment of full thickness cartilage defects in the knee joint with autologous chondrocyte transplantation.

OBJECTIVE: The high clinical and socio-economical impact of cartilage defects and chondral degeneration is well-known. After trauma or without a known etiology, often young patients suffer from pain and a loss of function leading into a decrease of physical activity and, more severe, into long term disability and unemployment. The clinical use of autologous chondrocyte transplantation was introduced in 1994 reporting the data of a pilot study. The objective of this study is to evaluate the efficacy of this method of surgery. METHODS: Autologous chondrocyte transplantation has been established in our department since 1995 for the treatment of large, full thickness cartilage defects which can be completely covered with hyaline-like cartilage without harming the subchondral bone plate. Our first patients (n=24) all showed Grade IV lesions and an average defect size of 6.27 cm2. All but 4 of the patients had at least 1 cartilage defect related operation on the knee. RESULTS: The patients and the clinicians rating indicated an increase of a modified Cincinnati Knee score from 3.6 point pre-operation to 6.9 points after 6 months and 8.1 points at 12 months on a scale from 1 (bad) to 10 (excellent). These results support the data of an international multicenter study with almost 2000 patients. The 5 year results described by the originate authors are good to excellent in 85%-95% with an adverse event rate of 5%. CONCLUSION: Autologous chondrocyte transplantation has to be considered a safe and effective method for the treatment of large full thickness cartilage defects. Alternative treatments are symptomatical: drilling, abrasion, lavage, chondroplasty, or osteotomies. The short term results are promising but a lot of patients have to be treated for osteoarthritis as a consequence of failure with total joint arthroplasty. Osteochondral transplantations have the disadvantage of limited harvesting sites and the impairment of the subchondral bone plate.

[Clinical and cell biology aspects of autologous chondrocytes transplantation]. / Klinische und zellbiologische Aspekte der autologen Chondrozytenimplantation.Methode, Indikationen und wissenschaftliche Ergebnisse.

The treatment of deep cartilage defects is a challenge for every orthopaedic surgeon. The potential for regeneration of cartilage tissue is minimal and leads to mechanically inferior fibrous tissue. The established techniques induce the growth of fibrous tissue but fail to prevent arthrosis. Autologous chondrocyte transplantation seems to be the most promising therapy concept with clinical relevance to reserves a full thickness cartilage defect with hyaline-like cartilage. Outcome studies with a follow up from 2-10 years show in up to 90 % good and excellent results for defects on the femoral condyle and 70 % for the patella. Mechanical testing of the regenerated cartilage showed almost similar stiffness as nearly normal hyaline cartilage. The available data justify the acceptance of autologous chondrocyte transplantation as a standard procedure for limited indications and well-trained surgeons. Result of already inaugurated studies will show the potential of chondrocyte transplantation to prevent osteoarthritis.

Postoperative ossifications of the shoulder. Incidence and clinical impact.

Periarticular ossifications of the shoulder after surgery have been described since the beginning of the century. Risk factors and the clinical impact of heterotopic bone formation have been discussed controversially. After open surgery on the shoulder, 131 patients (rotator cuff repair n = 106, acromioplasty n = 25) were included in a retrospective study if pre- and postoperative X-rays were available. The age of the 90 men and 41 women averaged 51 years (range 29-67 years). The minimum follow-up was 2 years. Also, 108 patients were interviewed by questionnaire to estimate the subjective outcome of the procedure (5 patients were reported dead). A clinical examination was carried out on 86 patients using the Constant score for evaluation of the objective outcome. Heterotopic ossifications were found in 35 cases (26.7%), 28 of them after rotator cuff reconstruction and 7 after acromioplasty. A good to excellent result was reported by 89% (n = 65) of the patients without and by 80% (n = 28) of the patients with ossifications. The Constant score averaged 69 points and 74 points (n = 60), respectively. A significant difference between the two collectives could not be calculated. As significant risk factors for the formation of heterotopic bone, the existence of osteoarthritis and the duration and complexity of the procedure could be cited. The appearance of periarticular ossifications after surgery of the shoulder seems to be of minor clinical impact. Severe cases with major functional deficits should and can be prevented by a fast and atraumatic operation technique.

[Arthroscopic therapy of osteochondrosis dissecans of the talus--follow-up with a new "Ankle Score"]. / Arthroskopische Therapie der Osteochondrosis dissecans des Talus--Nachuntersuchung mit einem neuen "Ankle Score".

INTRODUCTION: Since the advent of operative ankle arthroscopy specific treatment of osteochondritis dissecans of the talus underwent rapid progress. Besides optimizing well-known methods as drilling, spongeous plastic, curettage or refixation of dissecates new trends go to transplantation of cultivated cartilage and osteochondral allografts. Previous follow-up examinations suffer on the one hand from partially small numbers of cases, on the other hand comparisons are difficult because so far no rating system of the function of the upper ankle does exist. MATERIAL AND METHODS: Within three years 34 patients underwent arthroscopic treatment of osteochondritis dissecans of the talus, 16 with percutaneous drilling, 12 spongeous plastics, three refixations and three curettages. The average age of the 22 men and 12 women was 25 years (11-48 years). A newly developed score system and a follow up MRI was used in a follow-up of 29 of the patients. Up to 100 points are given in the categories pain, stability/insecurity, efficiency/painfree walking distance, gait, differences in circumference, motility and power. RESULTS: 27 of the 34 patients had a trauma history. 20 lesions were localized at the lateral talus, they all had a trauma history. In 7 of the 14 lesions at the medial part of the talus there was no evidence of trauma. The 29 patients in the follow-up achieved an average of 87 points, the 16 patients after K-wire drilling 85 points and the 12 patients after spongeous plastic 90 points. Deductions were noted likewise in the subjective and objective parameters. 100 points were reached by 4 patients. DISCUSSION: Cultured chondrozytes and osteochondral grafts are new trends in treatment of osteochondritis dissecans while arthroscopically controlled spongeous plastic after curettage and K-wire drilling represent the main component of early stages with intact or partially fractured cartilage surface. Results of K-wire drilling are negligible worse than those of spongeous plastic, which is attributed to a generous perforation of the sclerosis. This is contributed to an improved preoperative diagnosis with MRI.