Hydrogel-based autologous chondrocyte implantation leads to subjective improvement levels comparable to scaffold based autologous chondrocyte implantation.

PURPOSE: Scaffold-based autologous chondrocyte implantation is a well-established treatment for cartilage defects in the knee joint. Hydrogel-based autologous chondrocyte implantation using an in situ polymerizable biomaterial is a relatively new treatment option for arthroscopic cartilage defects. It is therefore important to determine if there are significant differences in the outcomes. The aim of this study is to compare the outcomes (using subjective parameters) of hydrogel-based autologous chondrocyte implantation (NOVOCART® Inject) with the outcomes of scaffold based autologous chondrocyte Implantation (NOVOCART® 3D) using biphasic collagen scaffold. METHODS: The data of 50 patients, which were paired with 25 patients in each treatment group, was analyzed. The main parameters used for matching were gender, number of defects and localization. Both groups were compared based on Visual Analogue Scale (VAS) and subjective IKDC scores, both of which were examined pre-operatively and after 6, 12 and 24 months. RESULTS: Significant benefits in both VAS and IKDC scores after 2 years of follow-up in both groups were found. Comparing the groups, the results showed that in the hydrogel-based autologous chondrocyte implantation group, significant changes in IKDC scores are measurable after 6 months, while it takes 12 months until they are seen in the scaffold based autologous chondrocyte group. CONCLUSION: Hydrogel-based autologous chondrocyte and scaffold based autologous chondrocyte show comparable improvements and significant benefits to the patients' subjective well-being after a 2-year-follow-up. LEVEL OF EVIDENCE: III.

Germany has a high demand in meniscal allograft transplantation but is subject to health economic and legal challenges: a survey of the German Knee Society.

PURPOSE: To determine the current status and demand of meniscal allograft transplantation (MAT) in Germany among members of the German Knee Society (= Deutsche Kniegesellschaft; DKG). METHODS: An online survey was conducted between May 2021 and June 2021 and sent to all members of the DKG. The survey questionnaire consisted of 19 questions to determine the demand and technical aspects of MAT among the participants and to identify areas of improvement in MAT in Germany. RESULTS: Overall, 152 participants, 136 (89.5%) from Germany, 8 (5.3%) from Switzerland, 6 (4.0%) from Austria, and 2 (1.3%) from other countries completed the online survey, with the majority working in non-academic institutions. According to the regulations of the DKG, 87 (57.2%) participants were board certified as specialized knee surgeons and 97 (63.8%) worked primarily in the field of orthopedic sports medicine. MAT was considered clinically necessary in Germany by 139 (91.5%) participants. Patient age (83.6%), post-meniscectomy syndrome in isolated lateral (79.6%) and medial (71.7%) meniscus deficiency, and functional and athletic demands (43.4%) were the most important determinants to consider MAT in patients. Participants reported that reimbursement (82.9%), jurisdiction over the use of donor grafts (77.6%), and the availability of meniscal allografts (76.3%) are the main challenges in performing MAT in Germany. The most frequently used meniscal allograft types by 54 (35.5%) participants who had already performed MAT were fresh-frozen grafts (56.6%), peracetic acid-ethanol sterilized grafts (35.9%), and cryopreserved grafts (7.6%). Participants reported to perform suture-only fixation more often than bone block fixation for both medial (73.6% vs. 22.6%) and lateral (69.8% vs. 24.5%) MAT. CONCLUSION: More than 90% of the responding members of the DKG indicated that MAT is a clinically important and valuable procedure in Germany. Reimbursement, jurisdiction over the use of donor grafts, and the availability of meniscal allografts should be improved. This survey is intended to support future efforts to facilitate MAT in daily clinical practice in Germany. LEVEL OF EVIDENCE: Level V.

Editorial Commentary: Bone Marrow Lesion as a Prognostic Factor for Osteochondral Allograft Transplantation of Cartilage Defects in the Knee Joint.

Bone marrow lesions (BML) can be categorized as ischemic, mechanical, or reactive. BML are associated with cartilage loss and can be interpreted as a "stress-related bone marrow edema," and are a consequence of subchondral overload due to lack of cartilaginous cushioning and load distribution. The prevalence, depth, and cross-sectional area of BML increase with the degree cartilage defect. There is a risk that bone marrow edema will progress to subchondral cysts, and cysts are a point of no return of a BML. Thus, successful treatment of cartilage damage requires causally addressing the bone marrow edema, and it is also crucial for the therapy of the BML that cartilage damage is completely treated. A postoperative BML is associated with incomplete defect coverage due to incomplete ingrowth of the osteochondral allograft with missing closure of the cartilage surface, or insufficient containment. Ideal treatment for a circumscribed subchondral BML is a single cylinder replacing the damaged cartilage and the entire BML with an osteochondral allograft. In the case of larger defects or larger BML, successful treatment of the cartilage defect is the critical point.

Third generation autologous chondrocyte implantation is a good treatment option for athletic persons.

PURPOSE: Autologous chondrocyte implantation is an established method for the treatment of joint cartilage damage. However, to date it has not been established that autologous chondrocyte implantation is an appropriate procedure for cartilage defects therapy in athletic persons. The aim of this study is to analyze if third-generation autologous chondrocyte implantation is an appropriate treatment for athletic persons with full cartilage defect of the knee joints. METHODS: A total of 84 patients were treated with third-generation autologous chondrocyte implantation (NOVOCART® 3D). The mean follow-up time was 8 years (5-14). Sports activity was measured via UCLA Activity Score and Tegner Activity Scale before the onset of knee pain and postoperatively in an annual clinical evaluation. 41 athletic persons and 43 non-athletic persons (UCLA-Cut-off: 7; Tegner Activity Scale-Cut-off: 4) were analyzed. Patient reported outcomes were captured using IKDC subjective, KOOS, Lysholm score and VAS score on movement. RESULTS: Patient reported outcomes (IKDC, VAS at rest, VAS on movement) showed significant improvement (p < 0.001) postoperatively. Athletic persons demonstrated significantly better results than non-athletic persons in the analyzed outcome scores (IKDC: p < 0.01, KOOS: p < 0.01, Lysholm score: p < 0.01). 96.4% of the patients were able to return to sport and over 50% returned or surpassed their preinjury sports level. The remaining patients were downgraded by a median of two points on the UCLA- and 2.5 on the Tegner Activity Scale. A shift from high-impact sports to active events and moderate or mild activities was found. Furthermore, it was shown that preoperative UCLA score and Tegner Activity Scale correlated significantly with the patient reported outcome postoperatively. CONCLUSION: Autologous chondrocyte implantation is a suitable treatment option for athletic persons with full-thickness cartilage defects in the knee. The return to sports activity is possible, but includes a shift from high-impact sports to less strenuous activities.

Effect of the defect localization and size on the success of third-generation autologous chondrocyte implantation in the knee joint.

INTRODUCTION: Femoral and patellar cartilage defects with a defect size > 2.5 cm2 are a potential indication for an autologous chondrocyte implantation (ACI). However, the influence of the localization and the absolute and relative defect size on the clinical outcome has not yet been determined. The purpose of this study is to analyze the influence of the localization and the absolute and relative defect size on the clinical outcome after third-generation autologous chondrocyte implantation. METHODS: A total of 50 patients with cartilage defects of the knee were treated with third-generation autologous chondrocyte implantation (Novocart® 3D). A match paired analysis was performed of 25 treated femoral and 25 treated patella defects with a follow-up of three years. MRI data was used to do the manual segmentation of the cartilage layer throughout the knee joint. The defect size was determined by taking the defect size measured in the MRI in relation to the whole cartilage area. The clinical outcome was measured by the IKDC score and VAS pre-operatively and after six, 12, 24, and 36 months post-operatively. RESULTS: IKDC and VAS scores showed a significant improvement from the baseline in both groups. Femoral cartilage defects showed significantly superior clinical results in the analyzed scores compared to patellar defects. The femoral group improved IKDC from 33.9 (SD 18.1) pre-operatively to 71.5 (SD 17.4) after three years and the VAS from 6.9 (SD 2.9) pre-operatively to 2.4 (SD 2.5) after three years. In the patellar group, IKDC improved from 36.1 (SD 12.6) pre-operatively to 54.7 (SD 20.3) after three years and the VAS improved from 6.7 (SD 2.8) pre-operatively to 3.4 (SD 2.) after three years. Regarding the defect size, results showed that the same absolute defect size at med FC (4.8, range 2-15) and patella (4.6, range 2-12) has a significantly different share of the total cartilaginous size of the joint compartment (med FC: 6.7, range 1.2-13.9; pat: 18.9, range 4.0-47.0). However, there was no significant influence of the relative defect size on the clinical outcome in either patellar or femoral localization. CONCLUSION: Third-generation autologous chondrocyte implantation in ACI-treated femoral cartilage defects leads to a superior clinical outcome in a follow-up of three years compared with patellar defects. No significant influence of the defect size was found in either femoral or patellar cartilage defects.

[Posterior meniscus root tears]. / Posteriore Wurzelverletzungen der Menisken.

Meniscus root tears are radial tears in the region of the posterior insertion zones. Medial root injuries usually occur in individuals > 50 years of age without adequate trauma and are associated with obesity and varus deformities. The root lesion leads to a loss of ring tension, which results in extrusion of the meniscus and a strong increase in joint pressure that is biomechanically equivalent to a complete meniscectomy. When indicating arthroscopic transosseous refixation of the medial root lesion, factors such as accompanying cartilage damage, osteoarthritis, obesity and varus deformity must be taken into account. Injuries to the root of the lateral meniscus are mostly observed in younger patients in combination with a rupture of the anterior cruciate ligament. Arthroscopic transosseous refixation in combination with cruciate ligament surgery is therefore also recommended for type I and type II lesions. In summary, both the medial and the lateral root lesions of the menisci are injuries with high biomechanical relevance.

Patient-Reported and Magnetic Resonance Imaging Outcomes of Third-Generation Autologous Chondrocyte Implantation After 10 Years.

PURPOSE: To evaluate the long-term clinical and radiologic outcomes of third-generation autologous chondrocyte implantation (ACI) for the treatment of focal cartilage defects of the knee. METHODS: Data capture was carried out between 2004 and 2018. Included were patients with cartilage defects of the knee joint with an International Cartilage Repair Society grade of III or higher treated with third-generation ACI who had a minimum follow-up period of 10 years. International Knee Documentation Committee scores and assessment of pain at rest and on movement using visual analog scale scores were captured preoperatively and at 6 months postoperatively, as well as annually thereafter. In addition, we performed magnetic resonance imaging examinations in 13 cases after 10 years. The MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) score was used to evaluate the ACI cartilage. RESULTS: A total of 54 patients met the inclusion criteria. Of these, 30 reached the 10-year follow-up point and were included in this assessment. At 10 years postoperatively, all clinical outcome parameters showed a statistically significant improvement compared with the preoperative situation, with a responder rate of 70%. The average MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) score after 10 years was 59.2 points (range, 20-100 points), and over 60% of the evaluated patients showed good integration of the implant at 10 years postoperatively. CONCLUSIONS: The clinical and radiologic findings of this study show that third-generation ACI is a suitable and effective option in the treatment of full-thickness cartilage defects of the knee. At 10 years after surgery, third-generation ACI shows stable results and leads to significant improvement in all clinical outcome parameters. Despite these results, revision surgery after third-generation ACI is common and was needed in 23% of patients in this study. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Third-generation autologous chondrocyte implantation after failed bone marrow stimulation leads to inferior clinical results.

PURPOSE: Third-generation autologous chondrocyte implantation (ACI) is an established and frequently used method and successful method for the treatment of full-thickness cartilage defects in the knee. There are also an increasing number of patients with autologous chondrocyte implantation as a second-line therapy that is used after failed bone marrow stimulation in the patient's history. The purpose of this study is to investigate the effect of previous bone marrow stimulation on subsequent autologous chondrocyte implantation therapy. In this study, the clinical results after the matrix-based autologous chondrocyte implantation in the knee in a follow-up over 3 years postoperatively were analysed. METHODS: Forty patients were included in this study. A total of 20 patients with cartilage defects of the knee were treated with third-generation autologous chondrocyte implantation (Novocart® 3D) as first-line therapy. The mean defect size was 5.4 cm2 (SD 2.6). IKDC subjective score and VAS were used for clinical evaluation after 6, 12, 24 and 36 months postoperatively. The results of these patients were compared with 20 matched patients with autologous chondrocyte implantation as second-line therapy. Matched pair analysis was performed by numbers of treated defects, defect location, defect size, gender, age and BMI. RESULTS: Both the first-line (Group I) and second-line group (Group II) showed significantly better clinical results in IKDC score and VAS score in the follow-up over 3 years compared with the preoperative findings. In addition, Group I showed significantly better results in the IKDC and VAS during the whole postoperative follow-up after 6, 12, 24 and 36 months compared to Group II with second-line autologous chondrocyte implantation (IKDC 6 months p = 0.015, 1 year p = 0.001, 2 years p = 0.001, 3 years p = 0.011). Additionally, we found a lower failure rate in Group I. No revision surgery was performed in Group I. The failure rate in the second-line Group II was 30%. CONCLUSION: This study showed that third-generation autologous chondrocyte implantation is a suitable method for the treatment of full-thickness cartilage defects. Both, Group I and Group II showed significant improvement in our follow-up. However, in comparing the results of the two groups, autologous chondrocyte implantation after failed bone marrow stimulation leads to worse clinical results. LEVEL OF EVIDENCE: III.

Revisability of polyetheretherketone suture anchors utilised in primary and revision Bankart repair.

BACKGROUND: Polyetheretherketone (PEEK) suture anchors are frequently used in Bankart shoulder stabilisation. This study analyzed the primary stability and revisability of PEEK anchors in-vitro in case of primary Bankart repair and revision Bankart repair after failed primary repair. METHODS: To simulate primary Bankart repair, 12 anchors (Arthrex PEEK PushLock® 3.5 mm) were implanted in 1, 3, 5, 7, 9 and 11 o'clock positions in cadaveric human glenoids and then cyclically tested. To simulate revision Bankart repair, 12 anchors were implanted in the same manner, over-drilled and 12 new anchors of the same diameter were implanted into the same bone socket as the primary anchors and then cyclically tested. The maximum failure loads (Fmax), system displacements, force at clinical failure and modes of failure were recorded. RESULTS: One primary anchor failed prematurely due to a technical problem. Three out of 12 revision anchors (25%) dislocated while setting the 25 N preload. The Fmax, the displacement and clinical failure of the remaining 9 revision anchors were non-significant when compared to the 11 primary repair anchors. The main mode of failure in the primary and revision Bankart surgery group was suture slippage. Anchor dislocations were observed four times in the primary and once in the revision repair groups. CONCLUSIONS: Revision Bankart repair using PEEK anchors of the same diameter in a pre-existing bone socket is possible but bears high risk of premature anchor failure and can jeopardize the reconstruction. PEEK suture anchor in revision Bankart surgery should be implanted in a new bone socket if possible.

Temporal TGF-ß Supergene Family Signalling Cues Modulating Tissue Morphogenesis: Chondrogenesis within a Muscle Tissue Model?

Temporal translational signalling cues modulate all forms of tissue morphogenesis. However, if the rules to obtain specific tissues rely upon specific ligands to be active or inactive, does this mean we can engineer any tissue from another? The present study focused on the temporal effect of "multiple" morphogen interactions on muscle tissue to figure out if chondrogenesis could be induced, opening up the way for new tissue models or therapies. Gene expression and histomorphometrical analysis of muscle tissue exposed to rat bone morphogenic protein 2 (rBMP-2), rat transforming growth factor beta 3 (rTGF-ß3), and/or rBMP-7, including different combinations applied briefly for 48 h or continuously for 30 days, revealed that a continuous rBMP-2 stimulation seems to be critical to initiate a chondrogenesis response that was limited to the first seven days of culture, but only in the absence of rBMP-7 and/or rTGF-ß3. After day 7, unknown modulatory effects retard rBMP-2s' effect where only through the paired-up addition of rBMP-7 and/or rTGF-ß3 a chondrogenesis-like reaction seemed to be maintained. This new tissue model, whilst still very crude in its design, is a world-first attempt to better understand how multiple morphogens affect tissue morphogenesis with time, with our goal being to one day predict the chronological order of what signals have to be applied, when, for how long, and with which other signals to induce and maintain a desired tissue morphogenesis.

Transient Bone Marrow Edema Syndrome versus Osteonecrosis: Perfusion Patterns at Dynamic Contrast-enhanced MR Imaging with High Temporal Resolution Can Allow Differentiation.

Purpose To prospectively evaluate the perfusion patterns at quantitative dynamic contrast material-enhanced (DCE) magnetic resonance (MR) imaging of transient bone marrow edema syndrome (TBMES) and avascular osteonecrosis. Materials and Methods Institutional review board approval and written informed consent were obtained. Thirty-two patients (21 men, 11 women; mean age, 48 years; 26 hips, 10 knees) underwent conventional MR imaging and a dynamic contrast-enhanced three-dimensional spoiled gradient-echo sequence at 3 T. Parameter maps for mean transit time (MTT) and plasma flow (PF) were evaluated qualitatively and quantitatively. Differences in perfusion patterns were analyzed by using the Fisher exact test. Regions of interest were drawn in areas of high PF and long MTT on each parametric map. Mean, median, standard deviation, minimum, and maximum values were determined. TBMES and osteonecrosis were compared statistically by using the Mann-Whitney U and Wilcoxon signed-rank tests, with a P value of less than .05 considered indicative of a significant difference. Results Nineteen joints with TBMES and 17 joints with osteonecrosis were evaluated. TBMES joints showed a subchondral elongated area of high PF and low MTT that was surrounded by an area of long MTT and low PF. Osteonecrosis joints showed a subchondral area with low or no detectable PF and MTT adjacent to the joint surface, which was surrounded by a rim of high PF and intermediate MTT. Patterns for TBMES and osteonecrosis did not overlap. A significant difference (P < .001) in PF in the immediate subchondral area was found between TBMES and osteonecrosis; in joints with osteonecrosis, this was comparable to background noise, and therefore, could not be quantified. In the circumscribed rim of high PF and intermediate MTT, which was only found in joints with osteonecrosis, mean ± standard deviation PF was 18.9 mL/100 mL per minute ± 11.0 and mean MTT was 213.3 seconds ± 56.8. No significant difference between TBMES and osteonecrosis was found for MTT (P = .09) and PF (P = .75) in the surrounding area. Conclusion Parameter maps derived at dynamic contrast-enhanced MR imaging with high temporal resolution can allow differentiation of osteonecrosis from TBMES in hip and knee joints. © RSNA, 2016 Online supplemental material is available for this article.

Cell Toxicity in Fibroblasts, Tenocytes, and Human Mesenchymal Stem Cells-A Comparison of Necrosis and Apoptosis-Inducing Ability in Ropivacaine, Bupivacaine, and Triamcinolone.

PURPOSE: To analyze the ability of ropivacaine, bupivacaine, and triamcinolone to induce apoptosis and necrosis in fibroblasts, tenocytes, and human mesenchymal stem cells. METHODS: Human dermal fibroblasts, adipose-derived human mesenchymal stem cells (hMSCs), and tenocytes gained from the rotator cuff tendon were seeded with a cell density of 0.5 × 104/cm2. One specimen of ropivacaine, bupivacaine, and triamcinolone was tested separately on the cells with separate concentrations of 0.5%, 0.25%, and 0.125% for each specimen. The negative control received no agent, only a change of medium. The incubation period for each agent was 30 minutes. After a change of medium and 1 hour, 24 hours, and 7 days of incubation, 104 cells were harvested and analyzed via fluorescence-activated cell sorting with double-staining with annexin V and propidium iodide. Statistical analysis to determine significant difference (P < .05) between the groups with SPSS statistics 23 through one-way analysis of variance with a univariate general linear model was performed. RESULTS: Bupivacaine showed necrosis-inducing effects on fibroblasts and tenocytes, with the necrotic effect peaking at 0.5% and 0.25%. Ropivacaine and triamcinolone caused no significant necrosis. Compared with fibroblasts and tenocytes, hMSCs did not show significant necrotic or apoptotic effects after exposure to bupivacaine. Overall, no significant differences in apoptosis were detected between different cell lines, varying concentrations, or time measurements. CONCLUSIONS: Bupivacaine 0.5% and 0.25% have the most necrosis-inducing effects on fibroblasts and tenocytes. Ropivacaine caused less necrosis than bupivaine. Compared with fibroblasts and tenocytes, hMSCs were not affected by necrosis using any of the tested agents. A significant apoptosis-inducing effect could not be detected for the different cell lines. CLINICAL RELEVANCE: Possible cell toxicity raises questions of concern for intra-articular injections using local anesthetics and corticosteroids. The present study demonstrates the necrotic and apoptotic effects of ropivacaine, bupivacaine, and triamcinolone and may give recommendations for intra-articular use of local anesthetics and corticosteroids.

Matrix based autologous chondrocyte implantation in children and adolescents: a match paired analysis in a follow-up over three years post-operation.

PURPOSE: The aim of this study is the investigation of the clinical results after third generation autologous chondrocyte implantation in the knee in a follow-up over three years post-operation. Our primary focus is on the effects of this procedure on children and adolescent patients as there is a lack of knowledge regarding the clinical outcomes in children/adolescents in particular when compared with adults. METHODS: A total of 40 patients (43 defects) <20 years with cartilage defects of the knee were treated with third generation ACI (Novocart® 3D). These defects were caused by osteochondritis dissecans (n = 13), acute trauma (<12 months) (n = 9), old trauma (>12 months) (n = 5) or unknown pathology (n = 13). The mean defect size was 5.2 cm2. IKDC subjective score and VAS (at rest and during activity) were used for clinical evaluation after 6, 12, 24 and 36 months post-operatively. The results of these patients were compared with 40 matched adult patients. Match paired analysis was performed by numbers of treated defects, defect location and defect size. All cartilage defects were arthroscopically classified with IKDC grade III-IV. All adult patients in the control group were treated with matrix based autologous chondrocyte implantation. RESULTS: All patients showed significantly better clinical results compared with the pre-operative findings in the follow-up over three years. We observed significantly better results in the IKDC score and VAS during the whole postoperative follow-up in children and adolescents after six, 12, 24 and 36 months compared with the adult control group. The IKDC score improved from 46.5 preoperative to 77.5 (+31) after three years in children and adolescents. Similarly, significantly lower stress pain after six months and one, two and three years was found in this group. CONCLUSION: This study showed that third generation autologous chondrocyte implantation is a suitable method for the treatment of full cartilage defects in children and adolescents.

Discrepancy between morphological findings in juvenile osteochondritis dissecans (OCD): a comparison of magnetic resonance imaging (MRI) and arthroscopy.

PURPOSE: The aim of this study was to assess the reliability of preoperative MRI for the staging of osteochondritis dissecans (OCD) lesions of the knee and the talus in juvenile patients, using arthroscopy as the gold standard of diagnosis. METHODS: Sixty-three juvenile patients (range 8-16 years) with an OCD of the knee or the talus underwent arthroscopy after MRI. In 54/9 out of 63 cases, 1.5/3 T MR scanners were used. The OCD stage was classified according the staging criteria of Dipaola et al. Arthroscopic findings were compared with MRI reports in each patient. RESULTS: From the 63 juvenile patients, MRI/arthroscopy revealed a stage I OCD in 4/19 patients, stage II in 31/22 patients, stage III in 22/9 patients and stage IV in 6/6 patients. No osteochondral pathology was evident in arthroscopy in seven out of 63 patients. The overall accuracy of preoperative MRI in staging an OCD lesion of the knee or the talus was 41.3%. In 33 out of 63 patients (52.4%), arthroscopy revealed a lower OCD stage than in the preoperative MRI grading, and in four out of 63 cases (6.4%), the intraoperative arthroscopic grading was worse than in preoperative MRI prior to surgery. The utilization of the 3 T MRI provided a correct diagnosis with 44.4%. CONCLUSIONS: Even with today's modern MRI scanners, it is not possible to predict an accurate OCD stage in children. The children's orthopaedist should not solely rely on the MRI when it comes to the decision to further conservative or surgical treatment of a juvenile OCD, but rather should take surgical therapy in consideration within persisting symptoms despite a low OCD stage provided by MRI. LEVEL OF EVIDENCE: III.

Primary stability of rotator cuff repair: can more suture materials yield more strength?

INTRODUCTION: It remains unclear if the increased biomechanical stability of the double-row repair is solely a result of the technique itself or due to the greater number of utilized materials. This study analyses the various rotator cuff (RC) repair interfaces and the influence of doubling the number of suture knots, stitch techniques and suture anchors on the primary stability of the RC reconstruction. MATERIALS AND METHODS: Established cyclic testing protocols were used to test the primary stability of the knot interface with a Duncan loop and Roeder knot, the tendon-to-suture interface with a single-stitch and Mason-Allen-stitch and the anchor-to-bone interface with OPUS Magnum 2® and BioCorkscrew® anchors. After doubling the materials, the interfaces were tested again and compared to the yielded solitary values. The maximum failure loads (Fmax), clinical failure (CF), system displacement (SD) and modes of failure were recorded. RESULTS: Doubling the amount of knots, stitches and suture anchors improved almost all interface parameters. For example, Fmax, CF and SD of the Roeder knot could be significantly improved from 142.5 N to 256.7 N, from 82.5 N to 155.0 N and from 0.45 mm to 0.20 mm, respectively. The Mason-Allen stitch's Fmax improved from 196.4 N to 324.9 N, and CF from 94.25 N to 139.8 N, with almost identical SD of 0.81 mm and 0.84 mm. Bio-Corkscrew® Fmax improved from 232.5 N to 317.5 N, CF from 182.5 N to 210 N, and SD from 0.85 mm to 0.64 mm. CONCLUSION: Doubling the number of knots, stitches and suture anchors increases the primary stability of the various RC repair interfaces and may result in RC rerupture rate reduction. Furthermore, this study suggests that a suture anchor loaded with two or three sutures may yield the same primary stability as two or three suture anchors loaded with a single suture. This in vitro biomechanical study focuses solely on the rotator cuff interfaces at time zero; the biological healing process was therefore not analysed and requires further investigation. CLINICAL RELEVANCE: Improved primary stability by increased number of suture materials may reduce rate of RC rerupture.

Analysis of the autologous chondrocyte quality of matrix-based autologous chondrocyte implantation in the knee joint.

PURPOSE: Matrix based autologous chondrocyte implantation is an established method for treatment of full cartilage defects in the knee joint, but little is known about the influence of the implanted autologous chondrocyte quality and its clinical value. The aim of this study is to evaluate the influence of the gene expression of the implanted autologous chondrocytes on the clinical outcomes in the follow-up period of three years. METHODS: Biological parameters of the implanted chondrocytes were analysed histologically and immunohistologically. An analysis of the gene expression of the relevant chondrogenic dedifferentiation markers was performed as well. In order to detect the rate of apoptosis, we analysed specific apoptosis markers. To evaluate the clinical outcome, the International Knee Documentation Committee (IKDC) subjective score and the visual analogue scale (VAS) were used pre-operatively and after 0.5, one, two and three years. RESULTS: Significantly improved clinical scores were observed. The subjective IKDC score increased from 50.6 ± 20.7 points to 69.3 ± 26.1 points at three years (p = 0.001). The implanted chondrocytes showed a typical expression of the chondrogenic markers with a high rate of collagen type II expression without dedifferentiation. The analysed differentiation, dedifferentiation and apoptosis markers showed no influence on the clinical outcome. CONCLUSIONS: The implanted autologous chondrocytes have a high chondrogenic quality with a high rate of collagen type II expression without dedifferentiation. An influence of differentiation, de-differentiation and apoptosis marker gene expression on the clinical outcomes could not be found in a follow-up period of three years. LEVEL OF EVIDENCE: Case series; Level of evidence, 3.

Revision surgery after third generation autologous chondrocyte implantation in the knee.

PURPOSE: Third generation autologous chondrocyte implantation (ACI) is an established treatment for full thickness cartilage defects in the knee joint. However, little is known about cases when revision surgery is needed. The aim of the present study is to investigate the complication rates and the main reasons for revision surgery after third generation autologous chondrocyte implantation in the knee joint. It is of particular interest to examine in which cases revision surgery is needed and in which cases a "wait and see" strategy should be used. METHODS: A total of 143 consecutive patients with 171 cartilage defects were included in this study with a minimum follow-up of two years. All defects were treated with third generation ACI (NOVACART®3D). Clinical evaluation was carried out after six months, followed by an annual evaluation using the International Knee Documentation Committee (IKDC) subjective score and the visual analogue scale (VAS) for rest and during activity. Revision surgery was documented. RESULTS: The revision rate was 23.4 % (n = 36). The following major reasons for revision surgery were found in our study: symptomatic bone marrow edema (8.3 %, n = 3), arthrofibrosis (22.2 %, n = 8) and partial graft cartilage deficiency (47.2 %, n = 17). The following revision surgery was performed: retrograde drilling combined with Iloprost infusion therapy for bone marrow oedema (8.4 %, n = 3), arthroscopic arthrolysis of the suprapatellar recess (22.2 %, n = 8) and microfracturing/antegrade drilling (47.3 %, n = 17). Significant improvements of clinical scores after revision surgery were observed. CONCLUSION: Revision surgery after third generation autologous chondrocyte implantation is common and is needed primarily in cases with arthrofibrosis, partial graft cartilage deficiency and symptomatic bone marrow oedema resulting in a significantly better clinical outcome.

Does footprint preparation influence tendon-to-bone healing after rotator cuff repair in an animal model?

PURPOSE: The aim of this study was to investigate the influence of footprint spongialization and radiofrequency ablation on rotator cuff repair outcomes compared with an untreated group in a rat model. METHODS: We randomly assigned 189 Sprague-Dawley rats to either a spongialization, radiofrequency ablation, or untreated group. After separation of the supraspinatus tendon from the greater tubercle, the footprint was prepared by removing the cortical bone with a burr (spongialization), was prepared by ablating soft tissue with a radiofrequency ablation device, or was left unaltered (untreated). Biomechanical testing (after 7 weeks, n = 165) and histologic analysis after 1 and 7 weeks (n = 24) followed reinsertion. RESULTS: The mean load to failure was 17.51 ± 4.46 N/mm(2) in the spongialization group, 15.56 ± 4.85 N/mm(2) in the radiofrequency ablation group, and 19.21 ± 5.19 N/mm(2) in the untreated group. A significant difference was found between the spongialization and radiofrequency ablation groups (P = .0409), as well as between the untreated and radiofrequency ablation groups (P = .0014). There was no significant difference between the spongialization and untreated groups (P = .2456). The mean area of fibrocartilage transition, characterized by the presence of type II collagen, was larger after 1 and 7 weeks in the spongialization group (0.57 ± 0.1 mm(2) and 0.58 ± 0.1 mm(2), respectively) and untreated group (0.51 ± 0.1 mm(2) and 0.51 ± 0.2 mm(2), respectively) than in the radiofrequency ablation group (0.11 ± 0.1 mm(2) and 0.4 ± 0.1 mm(2), respectively) with P < .05 and P < .01. CONCLUSIONS: The results of this study show that radiofrequency ablation of the footprint results in a poor biomechanical and histologic outcome in an animal model. No preparation of the footprint has the same effect as spongialization. CLINICAL RELEVANCE: Different techniques of footprint preparation in rotator cuff repair may influence tendon-to-bone healing.

Surgical treatment of patients with spondylodiscitis and neurological deficits caused by spinal epidural abscess (SEA) is a predictor of clinical outcome.

STUDY DESIGN: Retrospective study. OBJECTIVE: The purpose of this study was to investigate the question whether surgical treatment of patients with spondylodiscitis and neurological deficits caused by a spinal epidural abscess (SEA) is a predictor of clinical outcome. SUMMARY OF BACKGROUND DATA: Spondylodiscitis with an accompanying SEA is a serious medical condition that is associated with potentially high risk for long-term neurological morbidity. In the literature, up to 75% of patients suffer from neurological deficits related to SEA in spondylodiscitis. Independent of treatment, residual neurology persists at a high rate. METHODS: A retrospective analysis of 135 patients admitted to our department due to a diagnosis of spondylodiscitis was performed. Presence of SEA was evaluated based on computed tomography and magnetic resonance imaging. Neurological status was documented on admission and at discharge according to the Frankel Score. In addition, our patient population was separated into group I without neurological deficits (Frankel E) and group II with abnormal Frankel A-D. Surgical and nonsurgical therapy was retrospectively evaluated. Data were statistically analyzed using the 2-sided Fisher exact test. RESULTS: On admission, 102 patients were graded as Frankel E in group I. In group II, 15 were Frankel D, 8 Frankel C, 8 Frankel B, and 2 Frankel A. After treatment, 105 patients were Frankel E, 19 Frankel D, 4 Frankel C, 3 Frankel B, and none Frankel A. Four patients died because of severe comorbidities. In group II, 13 of 33 patients had a SEA. Twelve patients showed improvement in Frankel grade, 1 remained unchanged. Of the 20 patients in group II without a SEA, 11 improved and 9 remained unchanged. Twenty-eight of the 33 patients in group II were treated surgically. Patients in both groups with improved neurology showed an upgrade by 1 or 2 Frankel scores. There was no deterioration of neurology. The correlation between surgically treated patients with SEA in comparison with patients without SEA is considered to be statistically significant. CONCLUSION: Surgical treatment of patients with spondylodiscitis and neurological deficits caused by SEA is a predictor of clinical outcome.