Treatment of Large Cartilage Defects in the Knee by Hydrogel-Based Autologous Chondrocyte Implantation: Two-Year Results of a Prospective, Multicenter, Single-Arm Phase III Trial.

OBJECTIVE: To evaluate the clinical outcome of a hydrogel-based autologous chondrocyte implantation (ACI) for large articular cartilage defects in the knee joint. DESIGN: Prospective, multicenter, single-arm, phase III clinical trial. ACI was performed in 100 patients with focal full-thickness cartilage defects ranging from 4 to 12 cm2 in size. The primary outcome measure was the responder rate at 2 years using the Knee Injury and Osteoarthritis Outcome Score (KOOS). RESULTS: Two years after ACI treatment, 93% of patients were KOOS responders having improved by ≥10 points compared with their pre-operative level. The primary endpoint of the study was met and demonstrated that the KOOS response rate is markedly greater than 40% with a lower 95% CI (confidence interval) of 86.1, more than twice the pre-specified no-effect level. KOOS improvement (least squares mean) was 42.0 ± 1.8 points (95% CI between 38.4 and 45.7). Mean changes from baseline were significant in the overall KOOS and in all 5 KOOS subscores from Month 3 (first measurement) to Month 24 (inclusive) (P < 0.0001). The mean MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) score after 24 months reached 80.0 points (95% CI: 70.0-90.0 points) and 92.1 points in lesions ≤ 5 cm2. CONCLUSIONS: Overall, hydrogel-based ACI proved to be a valuable treatment option for patients with large cartilage defects in the knee as demonstrated by early, statistically significant, and clinically meaningful improvement up to 2 years follow-up. Parallel to the clinical improvements, MRI analyses suggested increasing maturation, re-organization, and integration of the repair tissue. TRIAL REGISTRATION: NCT03319797; EudraCT No.: 2016-002817-22.

Platelet-rich plasma (PRP) as therapy for cartilage, tendon and muscle damage - German working group position statement.

PURPOSE: Platelet rich plasma (PRP) is widely used in orthopaedics, but is still heavily debated. Therefore, a survey among the German "Working Group for Clinical Tissue Regeneration" of the German Society of Orthopaedics and Traumatology was conducted to achieve a consensus about the current therapeutical potential of PRP. METHODS: A first survey (n = 65 experts, all orthopaedic/trauma surgeons) was conducted (n = 13 questions). Following, a second round (n = 40 experts) was conducted with 31 questions to achieve consensus in 5 categories: three most common indications, PRP application, future research areas. RESULTS: Therapeutic PRP application was regarded as useful (89%), possibly even more important in the future (90%). Most common indications were tendon pathologies (77%), osteoarthritis (OA) (68%), muscle injuries (57%) and cartilage damage (51%). Consensus was reached in 16/31 statements. The application of PRP for early knee OA (Kellgren-Lawrence grade II) was regarded as potentially useful, as well as for acute and chronic tendinopathies. For chronic lesions (cartilage, tendons), multiple injections (2-4) were seen preferable to singular injections. However, no sufficient data exists on the time interval between the injections. Standardization of PRP preparation, application, frequency, as well as determining the range of indication is strongly recommended. CONCLUSIONS: There is a need of further standardization of the PRP preparation methods, indication and application protocols for knee OA and other indications, which must be further evaluated in basic science studies and randomized controlled clinical trials. LEVEL OF EVIDENCE: Consensus of expert opinion, Level V.

Degenerative isolated cartilage defects of the patellofemoral joint are associated with more severe symptoms compared to trauma-related defects: results of the German Cartilage Registry (KnorpelRegister DGOU).

PURPOSE: The purpose of this study was to utilize data from the German Cartilage Registry (KnorpelRegister DGOU) to examine the hypothesis that degenerative cartilage defects of the patellofemoral joint are associated with more severe clinical symptoms compared to trauma-related defects. METHODS: All patients with isolated focal cartilage defects of the patellofemoral joint registered in the German Cartilage Registry until May 2017 were included in the study. Patients with previous surgery of the ipsilateral knee were excluded. Baseline data including etiology (traumatic, degenerative), size, location and ICRS grade of the cartilage defects as well as the duration of symptoms were analyzed. Clinical symptoms were evaluated by means of the numeric analog scale (NAS) for pain and the Knee injury and Osteoarthritis Outcome Score (KOOS). Group comparisons were performed using the Mann-Whitney-U test along with the Chi-squared test and Fisher's exact test. A bivariate correlation analysis and a multivariable linear regression analysis were performed to investigate the association between the defect characteristics and the clinical scores. RESULTS: A total of 423 patients (203 traumatic and 220 degenerative defects) were included. Isolated degenerative cartilage defects were found to have significantly more trochlear locations (28% vs. 18%; p = 0.006), significantly less ICRS grade 4 lesions (50% vs. 73%; p = 0.002) and a significantly smaller defect size [median 300 (IQR 105-400) vs. 300 (200-400) mm2] when compared to those from traumatic etiology. Traumatic defects showed significantly better KOOS-ADL [77 (60-90) vs. 69 (56-82); p = 0.005], KOOS-pain [69 (56-81) vs. 61 (47-75); p = 0.001] and NAS [2 (1-5) vs. 4 (1-6); p = 0.005] scores compared to degenerative defects. The correlation analysis revealed only weak correlations between the quantitative defect characteristics and clinical scores. CONCLUSIONS: Degenerative isolated cartilage defects in the patellofemoral joint are associated with more severe clinical symptoms in comparison to trauma-related defects. Additionally, they show a larger variance regarding their location with more trochlear defects. LEVEL OF EVIDENCE: III.

What are the factors to affect outcome and healing of meniscus bucket handle tears?

INTRODUCTION: The purpose of this study is to identify patient, meniscus rupture and surgical characteristics that influence the outcome and clinical healing following operative repair of bucket handle tears. METHODS: Between 02/2006 and 10/2012, a total of 38 patients (14 women, 24 men) with bucket handle tears underwent surgical meniscus repair. There were 27 isolated repairs and 11 with concomitant anterior cruciate ligament (ACL) replacement. Patients were analyzed on an average of 44.4 months (range 15-96 months) after surgery by the use of standardized subjective scoring instruments [Lysholm, International Knee Documentation Committee (IKDC), Knee Injury and Osteoarthritis Outcome Score (KOOS) and Tegner Activity Scale (TAS)]. To identify factors affecting the outcome and suture survival, patient-specific, trauma-specific as well as meniscus- and surgery-specific factors were collected. Patients were divided in two groups with healed menisci (group 1) and re-rupture subjects (group 2). Meniscus re-rupture was defined as a clinical failure. RESULTS: There were 25 patients with healed menisci and 13 (34.2%) that sustained re-rupture and underwent either partial meniscectomy (n = 8) or re-suture (n = 5). Group 1 achieved slightly higher outcome compared to group 2 [Lysholm: 87.8 vs. 84.3 (p = 0.35), IKDC: 86.9 vs. 85.7 (p = 0.67), KOOS: 91.3 vs. 90.5 (p = 0.74)]. TAS was better for group 2 [5.9 vs. 6.8 (p = 0.36)]. Strong impact to result in a significantly increased outcome was identified for higher age, subjective knee joint stability, high preoperative Lysholm Score, short trauma-to-repair time, previous ACL reconstruction and a smaller number of sutures to fulfill meniscus repair. Lower patient age, male gender and higher activity level had the strongest impact to provoke re-rupture. CONCLUSION: Clinical outcome after meniscus bucket handle suture is satisfying. Re-rupture rate among this collective was 34.2%. Clear risk factors were identified for diminished clinical healing and outcome.

[Medial opening wedge high tibial osteotomy]. / Valgisierende Tibiakopfosteotomie in öffnender Technik.

OBJECTIVE: Reduction of the load to the medial compartment in patients with medial knee osteoarthritis and varus malalignment. Unloading of the posterolateral complex in varus deformity with complex ligamentous laxity. INDICATIONS: Medial knee osteoarthritis and varus malalignment with largely intact lateral and patellofemoral joint aspect. Complex ligament insufficiency combined with varus deformity. CONTRAINDICATIONS: Substantially impaired range of motion. SURGICAL TECHNIQUE: Medial skin incision on the proximal lower leg. Preparation of the pes anserinus. Marking of the osteotomy from the deepest point of the medial metaphysis laterally ascending. Biplane osteotomy, carefully protecting the posterior neurovascular structures, with ventral completion proximal or distal to the tibial tuberosity, depending on concomitant pathologies. Angular-stable plate fixation. POSTOPERATIVE MANAGEMENT: In general, early weight bearing is possible when angular-stable plate fixation is used. Often concomitant pathologies such as accompanying cartilage regenerative therapy necessitate longer unloading. Range of motion does not need to be restricted following stand-alone osteotomy. Orthoses are recommended regularly. RESULTS: Under the correct indication, the medial opening wedge high tibial osteotomy (OW-HTO) technique can achieve good results with high patient satisfaction, despite a relatively high statistical complication rate, provided that a standardized surgical technique is used. There is a tendency for a poorer outcome in patients with a body mass index above 30 and higher stages of osteoarthritis.

[S2k-Guideline on Meniscus Diseases: from Aetiology to Scoring]. / S2k-Leitlinie Meniskuserkrankung: Von der Ätiologie bis zum Scoring.

The number of patients with meniscal injuries is increasing constantly, but the treatment algorithms are undergoing continuous change. The effects of meniscal surgery, as well as the indications for the procedure, are currently a matter of heated debate. Various German speaking associations addressing topics related to the knee have joined forces to develop guidelines for the diagnosis, evaluation and therapy of meniscal lesions. The hope is that this first of two publications will shed light on some of the ongoing issues and offer guidance to health care professionals treating these patients.

[Treatment of Osteochondral Lesions in the Ankle: A Guideline from the Group "Clinical Tissue Regeneration" of the German Society of Orthopaedics and Traumatology (DGOU)]. / Behandlung osteochondraler Läsionen des Sprunggelenks: Empfehlungen der Arbeitsgemeinschaft Klinische Geweberegeneration der DGOU.

Background: Osteochondral lesions (OCL) of the ankle are a common cause of ankle pain. Although the precise pathophysiology has not been fully elucidated, it can be assumed that a variety of factors are responsible, mainly including traumatic events such as ankle sprains. Advances in arthroscopy and imaging techniques, in particular magnetic resonance imaging (MRI), have improved the possibilities for the diagnosis of OCLs of the ankle. Moreover, these technologies aim at developing new classification systems and modern treatment strategies. Material and Methods: This article is a review of the literature. Recommendations of the group "Clinical Tissue Regeneration" of the German Society of Orthopaedics and Traumatology (DGOU) for the treatment of OCLs of the ankle are presented. The review gives a concise overview on the results of clinical studies and discusses advantages and disadvantages of different treatment strategies. Results: Non-operative treatment shows good results for selected indications in children and adolescents, especially in early stages of osteochondritis dissecans (OCD). However, surgical treatment is usually indicated in OCLs in adolescents and adults, depending on the size and location of the lesion. Various arthroscopic and open procedures are frequently employed, including reattachment of the fragment, local debridement of the lesion with fragment removal and curettage of the lesion, bone marrow-stimulation by microfracture or microdrilling (antegrade or retrograde), and autologous matrix-induced chondrogenesis (AMIC®) - with or without reconstruction of a subchondral bone defect or cyst by autologous cancellous bone grafting. Isolated subchondral cysts with an intact cartilage surface can be treated by retrograde drilling and possibly additional retrograde bone grafting. For larger defects or as salvage procedure, osteochondral cylinder transplantation (OATS® or Mosaicplasty®) or matrix-induced autologous chondrocyte transplantation (MACT) are recommended. Transplantation of so-called (osteochondral) mega grafts, such as autologous bone grafts or allografts, are used for very large osteochondral defects that cannot be reconstructed otherwise. Implantation of the so-called "small metal implants" - such as HemiCAP Talus® - is reserved for selected cases after failed primary reconstruction. Corrective osteotomies are indicated in accompanying axial malalignments. Conclusions: There are several different treatment strategies for OCLs, but clinical studies are rare and evidence is limited. Therefore, interventional studies, e.g. randomised controlled trials (RCTs), but also observational studies, e.g. based on data of the Cartilage Registry of the German Society of Orthopaedics and Traumatology (www.knorpelregister-dgou.de), are needed and are recommended by the authors.

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.

[Osteochondral fractures at the knee joint]. / Osteochondrale Frakturen am Kniegelenk.

Osteochondral fractures are traumatic shearing injuries to the cartilage and the subchondral bone which lead to defects in the articular surface and potentially lead to further degeneration and arthritis. Early diagnosis and therapy are therefore very important. As the resolving power of conventional X-rays is limited for this situation, magnetic resonance imaging (MRI) is regarded as the gold standard for diagnostics. Concomitant injuries often occur, such as tearing of the anterior cruciate ligament (ACL) or patellar dislocation resulting in instability of the patella. Concerning treatment options for osteochondral fractures, there are two potential strategies that can be applied: the first is removal of small osteochondral fragments with subsequent formation of regeneration tissue and the second is refixation of the dislocated fragment and therefore a 1-stage reconstruction of the joint surface. It is important to also address concomitant injuries. Even though there is no consensus for a standardized or evidence-based therapy in literature, this article gives an overview of the diagnostics and available therapeutic options.

[The German Cartilage Registry (KnorpelRegister DGOU) for evaluation of surgical treatment for cartilage defects: experience after six months including first demographic data]. / Das KnorpelRegister DGOU zur Erfassung von Behandlungsergebnissen nach Knorpeloperationen: Erfahrungen nach 6 Monaten und erste epidemiologische Daten.

The German Cartilage Registry (KnorpelRegister DGOU) has been introduced in October 2013 and aims on the evaluation of patients who underwent cartilage repair for symptomatic cartilage defects. It represents a nation-wide cohort study which has been introduced by the working group "Tissue Regeneration" of the Germany Society of Orthopaedic Surgery and Traumatology and is technically based upon a web-based remote data entry (RDE) system. The present article describes first experiences with the registry including patient and treatment characteristics. Between October 2013 and April 2014, a total of 230 patients who had undergone surgical cartilage repair for symptomatic full-thickness cartilage defects of the knee has been included in the German Cartilage Registry from 23 cartilage repair centres. Mean age was 37.11 years (SD 13.61) and mean defect size was 3.68 cm(2) (SD 0.23). Since the introduction of the KnorpelRegister DGOU the total number of registered patients has increased steadily up to the most recent figure of 72 patients within one month. Patients were treated mainly according to the recommended therapies. The highest percentage in therapy is represented by the bone marrow stimulation techniques (55.02 %) as well as by the autologous chondrocyte transplantation (34.92 %). Unlike the patient collective in the majority of prospective randomised controlled trials, the patient population within the registry shows a high proportion of patients with accompanying pathologies, with an age of more than 50 years at the time of treatment and with unfavourably assessed accompanying pathologies such as an affection of the opposite cartilage surface or a previously resected meniscus. In summary, the technical platform and forms of documentation of the KnorpelRegister DGOU have proved to be very promising within the first six months. Unlike data from other clinical trials, the previous analysis of the patients' data and therapies reflects successfully the actual medical care situation of patients with cartilage defects of the knee joint. This analysis also provides new information on subgroups of patients that have not yet been recorded in the scientific literature. This will be part of the first analysis of clinical treatment data. An expansion of the KnorpelRegister DGOU to patients with cartilage defects of the ankle and hip joints is already decided upon and initialised.

Patellar fractures--a review of classification, genesis and evaluation of treatment.

The patellar bone is involved in repetitive, load bearing motion sequences every day and functions as a vectorial force translator. A fracture rate of 1% of all skeletal fractures is reported and surgical treatment often required. beside a direct trauma mechanism, indirect mechanism but as well as fatigue fractures after reconstructive knee surgery are published. The fracture management is dependent on the soft tissue condition and a variety of surgical options are known. new generation of low profile plates show promising results but the conventional cerclage wiring technique with K-wires is widely preferred. best functional results with sustainable stability are biomechanically seen after a combined fixation technique using anterior cerclage wiring with cannulated screw fixation. A definite algorithm of treatment of patellar bone fractures is yet not defied but a review of classification and surgical techniques should give assistance in decision making.

Alignment does not influence cartilage T2 in asymptomatic knee joints.

PURPOSE: To investigate whether the static knee alignment affects articular cartilage ultrastructures when measured using T2 relaxation among asymptomatic subjects. METHODS: Both knee joints (n = 96) of 48 asymptomatic volunteers (26 females, 22 males; 25.4 ± 1.7 years; no history of major knee trauma or surgery) were evaluated clinically (Lysholm, Tegner) and by MRI (hip-knee-ankle angle, standard knee protocol, T2 mapping). Group (n = 4) division was as follows: neutral (<1° varus/valgus), mild varus (2°-4° varus), severe varus (>4° varus) and valgus (2°-4° valgus) deformity with n = 12 subjects/group; n = 24 knees/group. Regions of interest (ROI) for T2 assessment were placed within full-thickness cartilage across the whole joint surface and were divided respecting compartmental as well as functional joint anatomy. RESULTS: Leg alignment was 0.7° ± 0.5° varus among neutral, 3.0° ± 0.6° varus among mild varus, 5.0° ± 1.1° varus among severe varus and 2.5° ± 0.7° valgus among valgus group subjects and thus significantly different. No differences between the groups emerged from clinical measures. No morphological pathology was detected in any knee joint. Global T2 values (42.3 ± 2.3; 37.7-47.9 ms) of ROIs placed within every knee joint per subject were not different between alignment groups or between genders, respectively. CONCLUSION: Static frontal plane leg malalignment does not affect cartilage ultrastructure among young, asymptomatic individuals as measured by T2 quantitative imaging. LEVEL OF EVIDENCE: Cross-sectional study, Level II-III.

[Post-treatment rehabilitation after autologous chondrocyte implantation: State of the art and recommendations of the Clinical Tissue Regeneration Study Group of the German Society for Accident Surgery and the German Society for Orthopedics and Orthopedic Surgery]. / Nachbehandlung bei der autologen Chondrozytentransplantation: Eine Bestandsaufnahme und Empfehlung der AG Klinische Geweberegeneration der DGU/DGOOC.

BACKGROUND: Over the course of the past two decades autologous chondrocyte implantation (ACI) has become an important surgical technique for treating large cartilage defects. The original method using a periostal flap has been improved by using cell-seeded scaffolds for implantation, the matrix-based autologous chondrocyte implantation (mb-ACI) procedure. MATERIAL AND METHODS: Uniform nationwide guidelines for post-ACI rehabilitation do not exist. A survey was conducted among the members of the clinical tissue regeneration study group concerning the current rehabilitation protocols and the members of the study group published recommendations for postoperative rehabilitation and treatment after ACI based on the results of this survey. RESULTS: There was agreement on fundamentals concerning a location-specific rehabilitation protocol (femoral condyle vs. patellofemoral joint). With regard to weight bearing and range of motion a variety of different protocols exist. Similar to this total agreement on the role of magnetic resonance imaging (MRI) for postsurgical care was found but again a great variety of different protocols exist. CONCLUSIONS: This manuscript summarizes the recommendations of the members of the German clinical tissue regeneration study group on postsurgical rehabilitation and MRI assessment after ACI (level IVb/EBM).

[Effect of continuous passive motion for cartilage regenerative surgery - a systematic literature review]. / Wirkung von passiven Motorbewegungsschienen nach knorpelregenerativen Eingriffen - eine systematische Literaturübersicht.

BACKGROUND: The aim of this systematic review was to evaluate treatment effects of continuous passive motion (CPM) after surgical cartilage repair. PATIENTS/MATERIAL AND METHODS: A literature search was conducted in the Cochrane Central Register of Controlled Trials, EMBASE, International Clinical Trials Registry Platform, MEDLINE, Trip Database and in bibliographies of included studies. Two independent researchers evaluated the quality of original investigations by the Cochrane Risk of Bias tool. Systematic reviews were checked by the CBO/Dutch Cochrane Centre Guideline. RESULTS: A total of 1541 studies was initially retrieved from the databases. After screening for inclusion criteria, one review and ten original papers could be included for further evaluation. Studies showed methodological weaknesses. Heterogeneity of outcome measures and the fact that 6 of 9 studies with an one-group pre-post design measured the combined effect of surgical treatment and CPM prevented a meta-analysis. CONCLUSION: Three studies described significant improvements with regard to subjective outcome such as pain, swelling, Quality Life Survey, Knee Society score, WOMAC score or rating Cincinnati due to the surgical treatment and the CPM intervention of cartilage defects in the knee. Six (case) studies suggested an enhanced cartilage quality of the patients after CPM. More high-quality randomised controlled trials are needed to provide high level evidence.

[Cartilage biopsy for autologous chondrocyte implantation (ACI)]. / Die Knorpelbiopsie im Rahmen der autologen Knorpelzelltransplantation (ACT).

Autologous chondrocyte implantation (ACI) is an established two-step procedure for the treatment of full-thickness cartilage defects of the knee. Cartilage harvest from the affected knee joint represents the first step of this procedure and is essential for further in vitro expansion of autologous chondrocytes. Nevertheless, the cartilage biopsy process itself is underrepresented in the scientific literature and currently there is only a limited amount of data available addressing this process. Biopsy location as well as the technique itself and instruments used for cartilage collection are not well defined and only little standardisation can be found. The article describes the relevant aspects of the biopsy in the context of ACI with regard to the literature available. Follow-up studies to better define and standardise the cartilage biopsy process are thus required.

Microporous calcium phosphate ceramics as tissue engineering scaffolds for the repair of osteochondral defects: Histological results.

Treatment of defects in joint cartilage aims to re-establish normal joint function. In vitro experiments have shown that the application of synthetic scaffolds is a promising alternative to existing therapeutic options. A sheep study was conducted to test the suitability of microporous pure ß-tricalcium phosphate (TCP) ceramics as tissue engineering scaffolds for the repair of osteochondral defects. Cylindrical plugs of microporous ß-TCP (diameter: 7mm; length: 25mm; porosity: 43.5±2.4%; pore diameter: ~5µm) with interconnecting pores were used. Scaffolds were seeded with autologous chondrocytes in vitro and cultured for 4weeks. A drill hole (diameter 7mm) was placed in both medial femoral condyles of sheep. For the left knee the defect was filled with a TCP plug and for the right knee the defect was left empty. After 6, 12, 26 and 52weeks, seven animals from each group were killed and studied. The samples were examined employing histological, histomorphometric and immunohistological methods as well as various imaging techniques (X-ray, microcomputer tomography and scanning electron microscopy). After explantation the cartilage defects were first assessed macroscopically. There were no signs of infection or inflammation. Histological grading scales were used for assessment of bony integration and cartilage repair. An increasing degradation (81% after 52weeks) of the ceramic with concomitant bone formation was observed. The original structure of cancellous bone was almost completely restored. After 26 and 52weeks, collagen II-positive hyaline cartilage was detected in several samples. New subchondral bone had formed. The formation of cartilage began at the outer edge and proceeded to the middle. According to the O'Driscoll score, values corresponding to healthy cartilage were not reached after 1year. Integration of the newly formed cartilage tissue into the surrounding native cartilage was found. The formation of biomechanical stable cartilage began at the edge and progressed towards the centre of the defect. After 1year this process was still not completed. Microporous ß-TCP scaffolds seeded with chondrocytes are suitable for the treatment of osteochondral defects.

[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.

Influence of rupture patterns of the medial patellofemoral ligament (MPFL) on the outcome after operative treatment of traumatic patellar dislocation.

PURPOSE: Patellar dislocation usually occurs to the lateral side, leading to ruptures of the medial patellofemoral ligament (MPFL) in about 90 % of all cases. Reliable prognostic factors for the stability of the patellofemoral joint after MPFL surgery and satisfaction of the patient have not been established as yet. METHODS: This multicentric study retrospectively included 40 patients with a mean age of 22.4 ± 8.1 years (range 9-48) from 5 German Trauma Departments with first-time traumatic patellar dislocation and operative treatment. Surgery was limited to soft tissue repairs, and a preoperative magnetic resonance imaging (MRI) was performed in all cases. Evaluation of the MRI included sulcus angle, dysplasia of the trochlea, depth and facet asymmetry of the trochlea, Insall-Salvati index, Tibial tuberosity to trochlear groove (TTTG) distance, and rupture patterns of the MPFL. Patients were interrogated after 2 years about recurrent dislocation, satisfaction, and the Kujala score. RESULTS: Trochlea facet asymmetry was significantly lower in patients with redislocation (23.5 ± 18.8) than in patients without redislocation (43.1 ± 16.5, p = 0.03). Patients with a patellar-based rupture were significantly younger (19.5 ± 7.2 years) than patients without patellar-based rupture (25.4 ± 8.1 years, p < 0.02). Patients with femoral-based ruptures were significantly older (25.7 ± 9.2 years) than patients without femoral-based rupture (19.7 ± 6.1 years, p < 0.02), and had a significantly higher TTTG distance (10.2 ± 6.9 vs. 4.5 ± 5.5, p < 0.02). Patients with incomplete ruptures of the MPFL had a significantly lower Insall-Salvati index (1.2 ± 0.2 vs. 1.4 ± 0.2, p = 0.05). The Kujala score in patients with redislocations was significantly lower (81.0 ± 10.5 points) than in patients without redislocation (91.9 ± 9.2 points, p < 0.02). CONCLUSION: Younger patients more often sustain patellar-based ruptures following first-time traumatic patella dislocation, while older patients more often sustain femoral-based ruptures of the MPFL. Incomplete MPFL ruptures are correlated with lower Insall-Salvati indices. Low trochlear facet asymmetry is correlated with higher rates of redislocation. These results may be of relevance for the operative and postoperative treatment in the future. LEVEL OF EVIDENCE: Prognostic study, Level IV.

Autologous chondrocyte implantation in children and adolescents.

PURPOSE: Autologous chondrocyte implantation (ACI) is a well-established treatment method for cartilage defects in knees. Age-related grouping was based on expression data of cartilage-specific markers. Specificities of ACI in the different populations were analysed. METHODS: Two hundred and sixty-seven patients undergoing ACI in the knee between 2006 and 2010 were included in this analysis. Cell characteristics and expression data of cartilage-specific surface markers as CD44, aggrecan and collagen type II were statistically analysed for age association. Epidemiological data of the defined groups were compared. Course of treatment was evaluated using MRI. RESULTS: A correlation analysis showed statistically significant associations between age and aggrecan or collagen type II expression in all patients <30 years. A cluster analysis could predict age-dependent expression of these markers separating groups with an average age of 18.1 ± 2.3 and 23.6 ± 4.2 years, respectively (p < 0.02). Discriminance analysis suggested the age border between adults and juveniles at about 20 years. There was no influence of age on cell characteristics or CD44 expression. In the 19 of 267 patients with an age ≤18 years, gender distribution was not different compared to adults, but patella was significantly more affected. Cartilage lesions were mainly caused by osteochondritis dissecans (OCD) and trauma. The Knee Osteoarthritis Scoring System in MRI reached 4.8 ± 2.3 points before, declining to 3.3 ± 2.3 points 6 and 12 months after the operation. CONCLUSIONS: Age-related expression of cartilage-specific markers allows definition of adolescents in cartilage regenerating surgery. Chondromalacia in these patients is mainly caused by OCD or trauma. LEVEL OF EVIDENCE: Case series, Level IV.