Long-Term Clinical and MRI Results of Matrix-Assisted Autologous Chondrocyte Implantation for Articular Cartilage Defects of the Knee.

OBJECTIVE: To evaluate the long-term clinical and radiological outcome of matrix-assisted autologous chondrocyte implantation (mACI) for articular cartilage defects in the knee joint. DESIGN: Clinical evaluation was assessed in 21 patients with full-thickness cartilage defects, International Cartilage Repair Society (ICRS) grade IV. Clinical scoring was performed preoperatively and 12 years after transplantation using the International Knee Documentation Committee (IKDC) score, the Lysholm score, the Knee injury and Osteoarthritis Outcome Score (KOOS), and the Noyes sports activity rating scale. Morphologic evaluation of the repair tissue was assessed by magnetic resonance imaging (MRI) in 14 patients using the Kreuz-Henderson score. RESULTS: Clinical evaluation revealed significant improvement in the IKDC, the Lysholm, the KOOS, and the Noyes score. Morphological evaluation by MRI showed moderate to complete defect filling in 10 of 14 patients, demonstrating normal to nearly normal values in mean 74.29% of all assessed parameters. Significant correlation of the parameter cartilage signal and clinical outcome was found with the IKDC, Lysholm, and KOOS subscales ADL (activities of daily living) and QoL (quality of life). CONCLUSIONS: The clinical and radiological outcomes 12 years after transplantation suggest the confirmation of the promising results of the mid-term follow-up. This study therefore provides first indications that the implantation of mACI might be a suitable option for long-term cartilage repair. Future controlled studies need to address the exact parameters influencing the long-term outcome of mACI.

Single-dose local anesthetics exhibit a type-, dose-, and time-dependent chondrotoxic effect on chondrocytes and cartilage: a systematic review of the current literature.

PURPOSE: Many studies have shown that local anesthetics may impede chondrocyte metabolism. However, the influence of a single-dose local anesthetics is controversial. The aim of this metaanalysis was to review the literature for studies investigating the cytotoxic effects of single-dose local anesthetics on chondrocytes and cartilage. METHODS: A comprehensive literature search was performed using established search engines (Medline, Embase) to identify studies, investigating the influence of single-dose local anesthetics on cartilage. The systematic analysis included the influence on histology, cell viability, morphology, and matrix production depending upon dose, exposure time, and type of local anesthetics. RESULTS: Twelve studies with four different local anesthetics were included in this metaanalysis. Bupivacaine and lidocaine were found to be more chondrotoxic than mepivacaine and ropivacaine. The amount of dead cells increased in a substance-, dose-, and time-dependent process. Osteoarthritic cartilage seems to be more vulnerable compared to intact cartilage. The toxic effects occur first in the superficial cartilage layers and include damage to membrane integrity, mitochondrial DNA, and nuclear changes. There is no study that could show a significant chondrotoxic effect with low concentrations of bupivacaine (0.0625%), ropivacaine (0.1 and 0.2%), and mepivacaine (0.5%). CONCLUSIONS: The cytotoxicity of local anesthetics on chondrocytes is dependent on dose, time, and type of local anesthetics. Single-dose intra-articular administration of local anesthetics impede chondrocyte metabolism and should be performed only with low concentrations for selected diagnostic purposes and painful joints. The use of lidocaine should be avoided. LEVEL OF EVIDENCE: II.

Treatment of a Focal Articular Cartilage Defect of the Talus with Polymer-Based Autologous Chondrocyte Implantation: A 12-Year Follow-Up Period.

Autologous chondrocyte implantation (ACI) is a first-line treatment option for large articular cartilage defects. Although well-established for cartilage defects in the knee, studies of the long-term outcomes of matrix-assisted ACI to treat cartilage defects in the ankle are rare. In the present report, we describe for the first time the long-term clinical and radiologic results 12 years after polymer-based matrix-assisted ACI treat a full-thickness talar cartilage defect in a 25-year-old male patient. The clinical outcome was assessed using the visual analog scale and Freiburg ankle score, magnetic resonance imaging evaluation using the Henderson-Kreuz scoring system and T2 mapping. Clinical assessment revealed improved visual analog scale and Freiburg ankle scores. The radiologic analysis and T2 relaxation time values indicated the formation of hyaline-like repair tissue. Polymer-based autologous chondrocytes has been shown to be a safe and clinically effective long-term treatment of articular cartilage defects in the talus.

Patient-specific factors influencing the traction forces in hip arthroscopy.

INTRODUCTION: The application of traction in hip arthroscopy is associated with peri-operative complications. Within a therapeutic case series, patient-related factors correlating with high-traction forces during hip arthroscopy and occurring complications should be identified. MATERIALS AND METHODS: In 30 male and 38 female patients (mean age: 44.5 years), intra-operative traction forces were monitored continuously using a specialised measurement device. A multivariate analysis was employed to identify patient-related factors influencing the traction force. Peri-operative complications (follow-up: 12 weeks) were evaluated by performing a single-case analysis. RESULTS: The mean initial force prior to penetration of the capsule ("initial force") was 477 N (men: 517 N; women: 444 N), decreasing after capsulotomy by an average of 17 %. The male gender (p < 0.001), Kellgren and Lawrence radiographic stage (p = 0.037), low minimum joint-space width (p = 0.029) and high body height/weight (p = 0.003/0.037) correlated significantly with higher distraction forces. The patient age and type of anaesthesia (general versus spinal) were not relevant. Complications were observed in ten patients on the first post-operative day. In two of these patients a partial sensory deficit of the lateral cutaneous femoral nerve persisted after 12 weeks. All patients with complications required initial traction forces of >400 N. CONCLUSIONS: The study revealed several patient-specific risk factors correlating with high-traction forces during hip arthroscopy. With view to potential complications, these patient groups require special attention during surgical treatment as well as in future studies.

Platelet-Rich Plasma Preparation Types Show Impact on Chondrogenic Differentiation, Migration, and Proliferation of Human Subchondral Mesenchymal Progenitor Cells.

PURPOSE: To evaluate the chondrogenic potential of platelet concentrates on human subchondral mesenchymal progenitor cells (MPCs) as assessed by histomorphometric analysis of proteoglycans and type II collagen. Furthermore, the migratory and proliferative effect of platelet concentrates were assessed. METHODS: Platelet-rich plasma (PRP) was prepared using preparation kits (Autologous Conditioned Plasma [ACP] Kit [Arthrex, Naples, FL]; Regen ACR-C Kit [Regen Lab, Le Mont-Sur-Lausanne, Switzerland]; and Dr.PRP Kit [Rmedica, Seoul, Republic of Korea]) by apheresis (PRP-A) and by centrifugation (PRP-C). In contrast to clinical application, freeze-and-thaw cycles were subsequently performed to activate platelets and to prevent medium coagulation by residual fibrinogen in vitro. MPCs were harvested from the cortico-spongious bone of femoral heads. Chondrogenic differentiation of MPCs was induced in high-density pellet cultures and evaluated by histochemical staining of typical cartilage matrix components. Migration of MPCs was assessed using a chemotaxis assay, and proliferation activity was measured by DNA content. RESULTS: MPCs cultured in the presence of 5% ACP, Regen, or Dr.PRP formed fibrous tissue, whereas MPCs stimulated with 5% PRP-A or PRP-C developed compact and dense cartilaginous tissue rich in type II collagen and proteoglycans. All platelet concentrates significantly (ACP, P = .00041; Regen, P = .00029; Dr.PRP, P = .00051; PRP-A, P < .0001; and PRP-C, P < .0001) stimulated migration of MPCs. All platelet concentrates but one (Dr.PRP, P = .63) showed a proliferative effect on MPCs, as shown by significant increases (ACP, P = .027; Regen, P = .0029; PRP-A, P = .00021; and PRP-C, P = .00069) in DNA content. CONCLUSIONS: Platelet concentrates obtained by different preparation methods exhibit different potentials to stimulate chondrogenic differentiation, migration, and proliferation of MPCs. Platelet concentrates obtained by commercially available preparation kits failed to induce chondrogenic differentiation of MPCs, whereas highly standardized PRP preparations did induce such differentiation. These findings suggest differing outcomes with PRP treatment in stem cell-based cartilage repair. CLINICAL RELEVANCE: Our findings may help to explain the variability of results in studies examining the use of PRP clinically.

Importance of a distal centralizer in experimental malpositioning of cemented stems. A biomechanical study on human femora.

INTRODUCTION: Femoral centralizers in total hip arthroplasty (THA) are designed to improve the neutral implant position and ensure a homogeneous cement mantle without implant-bone impingement. To date there are no data about the cement mantle configuration and implant position after malinsertion, as seen in mini-open approaches or adipose patients with a limited view. The present biomechanical study was performed to investigate whether a distal centralizer may correct and optimize the position of a malinserted femoral stem. MATERIAL AND METHODS: Thirteen MS 30 stems with and without a distal centralizer each were implanted in paired fresh human femora. Malinsertion was performed using a 3D guiding device with 10° deviation to the femoral axis in the sagittal plane. The thickness of the cement mantle was measured on the anterior, posterior, medial and lateral side of the implanted stem at a distance of 1 cm each. For each side data were taken at 13 points. RESULTS: Digital evaluation of the cement mantle thickness revealed compareable values in frontal plane when a centralizer was used (p > 0.4). In contrast the cement mantle thicknesses without a centralizing device varied in the distal region between 3.38 mm and 5.09 mm (p ≤ 0.001) and in the central region between 3.52 mm and 4.19 mm (p ≤ 0.009). CONCLUSIONS: A distal centralizer allows a more uniform cement mantle and neutral alignment even with a malinsertion of the femoral stem. This could reduce the failure rate and early loosening in complex THA.

Fibronectin stimulates migration and proliferation, but not chondrogenic differentiation of human subchondral progenitor cells.

AIMS: To evaluate the impact of human plasma-derived fibronectin (FN) on human subchondral mesenchymal progenitor cells regarding cell migration, proliferation, and chondrogenic differentiation. MATERIALS & METHODS: Human subchondral mesenchymal progenitor cells were analyzed for their migration capacity upon treatment with human plasma-derived FN. Proliferation activity was evaluated by DNA content. For chondrogenesis, cells were cultured in high-density pellet cultures in the presence of FN, TGFß3, and a combination thereof. RESULTS: Treatment of progenitors with FN significantly increased the number of migrating cells and elevated proliferative activity. Histological staining indicated formation of an extracellular matrix with type II collagen. Gene expression analysis gave no evidence for chondrogenic differentiation mediated by FN, but revealed a significant induction of type II collagen expression. CONCLUSION: FN has a potential to recruit human subchondral mesenchymal progenitor cells, possibly supporting proliferation and matrix assembly in cartilage repair procedures using bioactive implants after microfracture treatment.

Importance of sports in cartilage regeneration after autologous chondrocyte implantation: a prospective study with a 3-year follow-up.

BACKGROUND: There have been no data in the literature reporting the influence of sports on the outcome of autologous chondrocyte implantation in chondral defects of the knee. HYPOTHESIS: Sports can improve the result of autologous chondrocyte implantation in postoperative follow-up. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Between 1997 and 2003, 118 patients with symptomatic isolated chondral lesions of the knee underwent autologous chondrocyte implantation. According to the sports activity level before the start of symptoms, patients were assigned to 2 groups: group II with no or rare sports involvement (1-3 times/month); group I with regular (1-3 times/week) or competitive sports (4-7 times/week). All patients underwent clinical and magnetic resonance imaging evaluation preoperative and 6, 18, and 36 months after autologous chondrocyte implantation. RESULTS: Group I patients showed significantly better results (< .01) in the International Cartilage Repair Society and Cincinnati scores than group II patients. Preoperative evaluation revealed no correlation between the sports activity levels and the clinical scores (P > .05). However, from the sixth month on, correlation was statistically significant, increasing from 6 to 18 months, and from 18 to 36 months postoperatively. CONCLUSION: Physical training improves long-term results after autologous chondrocyte implantation of the knee and should be carried out for at least 2 years after surgery.

Mosaicplasty with autogenous talar autograft for osteochondral lesions of the talus after failed primary arthroscopic management: a prospective study with a 4-year follow-up.

BACKGROUND: There have been limited data in the literature reporting the results of osteochondral autografting for osteochondral lesions of the talus that have failed arthroscopic treatment. HYPOTHESIS: Osteochondral autografting can produce significant clinical improvement and a high rate of healing of osteochondral defects of the talus that have failed arthroscopic treatment. STUDY DESIGN: Cohort study; Level of evidence, 4. METHODS: Between 1998 and 2003, 35 patients (18 men, 17 women) with osteochondral talar lesions for which arthroscopic excision, curettage, and drilling had failed, underwent mosaicplasty with an osteochondral graft harvested from the ipsilateral talar articular facet. A malleolar osteotomy or a tibial wedge osteotomy was used for central or posterior lesions that could not otherwise be reached. The mean age of the patients was 30.9 years, and the mean follow-up was 48.9 months. RESULTS: The American Orthopaedic Foot and Ankle Society Ankle Hindfoot scale score in patients without osteotomy rose by 39 points (P = .0001); with malleolar osteotomy, by 30.1 points (P = .017); with tibial wedge osteotomy, by 34.9 points (P = .0002); and with the posterolateral approach, by 32 points. The Wilcoxon test revealed a significant difference between patients without and with osteotomy (P

The anterior approach for the treatment of posterior osteochondral lesions of the talus: comparison of different surgical techniques.

INTRODUCTION: Most of all osteochondral talar lesions are located in the middle and posterior area of the talar surface. Malleolar osteotomy is often used to access the defect but may be associated with malunion or secondary osteoarthritis. We present an alternative approach to the talus with temporary removal and replacement of a tibial bone block and compare it with other anterior approaches described in the literature. PATIENTS AND METHODS: Thirteen patients (5 males, 8 females) with an average age of 27.2 years and an osteochondral talar lesion were included in our study. All patients were previously operated on the same ankle. Ten lesions were caused by a sports injury. The average follow up was 45 months. The patients were evaluated before and after surgery using the ankle and hindfood score (AOFAS). For the analyses baseline clinical data were compared with follow up data using the Wilcoxon test. RESULTS: The overall improvement between the preoperative and postoperative AOFAS scores was an average of 34.9 points (P=0.0002). No complications occurred at the site of the tibial bone block and the donor site at the talus. There were no patients with recurrence or an ankle osteoarthrosis in the follow up period. CONCLUSION: The removal of a tibial bone block and its subsequent replacement is a useful technique to access osteochondral talar lesions for osteochondral transplantation for which arthroscopic interventions have failed. The results are comparable to other anterior approaches described in the literature.

Stress fractures in adolescent competitive athletes with open physis.

There have been no studies devoted exclusively to stress fractures in competitive athletes with immature skeletal systems so far. The object of this case series was to describe special features of stress fractures in athletes with immature skeletal systems, with special reference to sport-specific strain, diagnosis and treatment results. The study population was made up of 19 children and adolescents with a total of 21 stress fractures. The average observation period was 4.83 years [standard deviation (SD) 2.69] and the average age at diagnosis, 14.04 years (SD 4.7). The lower extremity was affected in most of our cases. In adolescent athletes, endurance sports appear to lead preferentially to stress fractures in the region of the metatarsal bones, while sports requiring sudden stops at high speed appear to increase the risk of fractures in the region of the tibial diaphysis (P=0.0322). Most (20 of 21) of the fractures in this study were treated conservatively with refraining from athletic activity and reduction of stress/weight-bearing for an average of 6.73 weeks (SD 2.91). In five cases the extremity was in addition immobilized in a plaster cast for 5.32 weeks (SD 2.21). Complete healing was achieved in 14 cases. In seven cases, however, the treatment did not lead to a satisfactory outcome. Most of the patients whose symptoms persisted over a long period had fractures in the tibia and were engaged in sports requiring frequent sudden stops. Our data suggest that stress fractures in athletes, whose skeletal systems are still immature, lead to a clinical picture that does not always culminate in a good outcome of treatment. We therefore recommend a thorough and early diagnostic investigation (including MRI) and consistent treatment whenever a patient's history and clinical picture give any indication that a stress fracture might be present.