Single-Stage Preparation of Human Cartilage Grafts Generated from Bone Marrow-Derived CD271+ Mononuclear Cells.

Due to the limited self-healing capacity of articular cartilage, innovative, regenerative approaches are of particular interest. The use of two-stage procedures utilizing in vitro-expanded mesenchymal stromal cells (MSCs) from various cell sources requires good manufacturing practice-compliant production, a process with high demands on time, staffing, and financial resources. In contrast, one- stage procedures are directly available, but need a safe enrichment of potent MSCs. CD271 is a surface marker known to marking the majority of native MSCs in bone marrow (BM). In this study, the feasibility of generating a single-stage cartilage graft of enriched CD271+ BM-derived mononuclear cells (MNCs) without in vitro monolayer expansion from eight healthy donors was investigated. Cartilage grafts were generated by magnetic-activated cell sorting and separated cells were directly transferred into collagen type I hydrogels, followed by 3D proliferation and differentiation period of CD271+, CD271-, or unseparated MNCs. CD271+ MNCs showed the highest proliferation rate, cell viability, sulfated glycosaminoglycan deposition, and cartilage marker expression compared to the CD271- or unseparated MNC fractions in 3D culture. Analysis according to the minimal criteria of the International Society for Cellular Therapy highlighted a 66.8-fold enrichment of fibroblast colony-forming units in CD271+ MNCs and the only fulfillment of the MSC marker profile compared to unseparated MNCs. In summary, CD271+ MNCs are capable of generating adequate articular cartilage grafts presenting high cell viability and notable chondrogenic matrix deposition in a CE-marked collagen type I hydrogel, which can obviate the need for an initial monolayer expansion.

Detection of articular perforations of the proximal humerus fracture using a mobile 3D image intensifier - a cadaver study.

BACKGROUND: The purpose of this study was to investigate the accuracy of perforation detection with multiplanar reconstructions using a mobile 3D image intensifier. METHODS: In 12 paired human humeri, K-wires perforating the subchondral bone and placed just below the cartilage level were directed toward five specific regions in the humeral head. Image acquisition was initiated by a fluoroscopy scan. Within a range of 90°, 45° external rotation (ER) and 45° internal rotation (IR). The number and percentage of detected perforating screws were grouped and analyzed. Furthermore, the fluoroscopic images were converted into multiplanar CT-like reconstructions. Each K-wire perforation was characterized as "detected" or "not detected". RESULTS: In the series of fluoroscopy images in the standard neutral position at 30° internal rotation, and 30° external rotation, the perforations of all K-wires (n = 56) were detected. Twenty-nine (51.8%) of them were detected in one AP view, 22 (39.3%) in two AP views, and five (8.9%) in three AP views. All K-wire perforations (100%, n = 56) were detected in multiplanar reconstructions. CONCLUSION: In order to reveal all of the intraoperative and postoperative screw perforations in a "five screw configuration", conventional AP images should be established in both the neutral positions (0°), at 30° internal rotation and 30° external rotation. Alternatively, the intraoperative 3D scan with multiplanar reconstructions enables a 100% rate of detection of the screw perforations.

Detection of primary screw perforation in locking plate osteosynthesis of proximal humerus fracture by intra-operative 3D fluoroscopy.

PURPOSE: The purpose of this study was to identify the rate of primary screw perforations after osteosynthesis of proximal humerus fractures with intra-operative 3D fluoroscopy and to analyse the rate of secondary screw perforations as well as complications, outcome, and revision surgeries after a minimum of 12 months. MATERIALS AND METHODS: Thirty-three patients (20 female, 13 male, median age 67 years, range 35-85 years) with displaced proximal humerus fractures were included. After reduction and fixation, an intra-operative 3D fluoroscopy was performed to evaluate primary screw perforations (PS) and screws with "near perforation" (nPS). These screws were changed intra-operatively. Patients were followed-up for a minimum of 12 months. Clinical and radiological parameters, such as secondary screw perforation, secondary loss of reduction, or functional outcome, were investigated. RESULTS: In six patients (18.2%), humeral head screws were changed due to primary PS (n = 2) or nPS (n = 4) after the intra-operative 3D fluoroscopy. Follow-up revealed an adapted constant score (%CMS) of 76.2% after a mean follow-up of 17.7 months. Two secondary screw perforations were observed (6%). Loss of reduction was observed in eight patients (24.2%). CONCLUSION: The intra-operative 3D reveals a high rate of primary screw perforations or near perforations. Immediate change of these screws may lead to a lower rate of secondary screw perforations and, therefore, reduce post-operative complications.

Endoscopic Removal of a Scapular Osteophyte Using Scapulothoracic Arthroscopy.

This article describes the removal of a scapular osteophyte from the subscapular space by scapulothoracic arthroscopy. The endoscopic technique allows a gentle approach to the subscapular space without causing a large amount of surgical trauma and therefore leads to good cosmetic and functional results.

The bicipital groove as a landmark for reconstruction of complex proximal humeral fractures with hybrid double plate osteosynthesis.

BACKGROUND: Complex proximal humerus fractures with metaphyseal comminution remain challenging regarding reduction and stability. In most fracture patterns the hard bone of the bicipital groove remains intact. In this case series, we describe a novel technique of hybrid double plate osteosynthesis of complex proximal humerus fractures with metaphyseal comminution. METHODS: In randomly chosen shoulder specimens and synthetic bones, pilot studies for evaluation of the feasibility of the technique were performed. Between 4/2010 and 1/2012 10 patients underwent hybrid double plate osteosynthesis. Seven patients (4 male, 3 female, mean age was 50 years (range 27-73)) were available for retrospective analysis. Based on plain radiographs (anterior-posterior and axial view), the fractures were classified according to the Orthopaedic Trauma Association classification (OTA) and by descriptive means (head-split variant (HS), diaphyseal extension or comminution (DE)). RESULTS: Follow-up radiographs demonstrated complete fracture healing in six patients and one incomplete avascular necrosis. None of the patients sustained loss of reduction. Three patients where reoperated. The medium, not adapted, Constant score was 80 Points (58-94). Patients subjective satisfaction was graded mean 3 (range: 0-6) in the visual analog scoring system (VAS). CONCLUSION: The technique of hybrid double plate osteosynthesis using the bicipital groove as anatomic landmark may re-establish shoulder function after complex proximal humerus fractures in two dimensions. Firstly the anatomy is restored due to a proper reduction based on intraoperative landmarks. Secondly additional support by the second plate may provide a higher stability in complex fractures with metaphyseal comminution.

Snapping knee syndrome caused by semitendinosus and semimembranosus tendons. A case report.

We report the case of a 24-year-old female triathlon athlete with a snapping syndrome of both the distal semimembranosus and the semitendinosus tendon which has not been described so far. The semitendinosus tendon was harvested whereupon snapping has diminished. Tenoscopy and digital palpation showed the semimembranosus tendon to cause the snapping, as well. A careful step-by-step release of the anterior insertion of the tendon was performed with the result of a snapping-free range of motion of the patient's knee.

Arthroscopically guided navigation for repair of acromioclavicular joint dislocations: a safe technique with reduced intraoperative radiation exposure.

BACKGROUND: Accuracy evaluation of navigated image free placement of double cortical fixation buttons for coracoclavicular tunnel position in comparison to conventional drill guide based placement. METHODS: Twenty-six patients with acute acromioclavicular joint instability were included in this non-randomized cohort study. All patients were treated with a Double- TightRope technique. In 13 cases the conventional drill guide based placement was used (group 1). In 13 patients surgery was performed as a navigated procedure with a fluoro-free optoelectronic system (group 2). The number of coracoclavicular drillings per patient (First pass accuracy; FPA (%)) was documented, the subcoracoidal position of the fixation buttons has been evaluated and graded as "intended position achieved (IPA)" or "intended position not achieved (IPnA)". RESULTS: In group 1 drilling had to be repeated in four patients (30.8 %) to achieve proper placement of the subcoracoidal fixation buttons. 100 % first pass accuracy was observed in group 2 (p = 0.03). In group 1, the intended position of the subcoracoid buttons was not achieved (IPnA) in six patients (46.2 %). In group 2 all intended positions were achieved (p = 0.005). CONCLUSION: Arthroscopic controlled fluoro-free navigated coracoclavicular drilling for the repair of acromioclavicular joint dislocation has higher first pass accuracy in comparison to conventional drill guide based placement. Therefore the navigation enables a precise position of the drill holes, may reduce the risk of an iatrogenic coracoid fracture and migration of fixation devices. TRIAL REGISTRATION: Local institutional review board No. 061-14-10032014.

Image-free navigated coracoclavicular drilling for the repair of acromioclavicular joint dislocation: a cadaver study.

BACKGROUND: Reconstruction of the coracoclavicular ligament functions to restore anatomic alignment of the clavicle and may improve biomechanical function and clinical outcomes. Improper placement of the coracoclavicular tunnel may inherently weaken the coracoid. The purpose of this study was to evaluate the feasibility and accuracy of navigated image-free placement of K-wires for coracoclavicular tunnel position in comparison to conventional drill guide-based placement. MATERIALS AND METHODS: Eight human shoulder specimens were assigned for conventional technique with a coracoclavicular guide device (group CP) and the paired contralateral side for the navigated procedure (group NP) with an optoelectronic system with a fluoro-free software module. First-pass accuracy (%) and the K-wire trajectory (lateral-center orientation (LC), center-center (CC) orientation and medial-center orientation (MC) were measured. RESULTS: In all navigated K-wires a 100 % first-pass accuracy was observed. In three of the eight (37.5 %) specimens of the drill guide-based group, drilling had to be repeated. One of them had to be repeated twice, resulting in eight versus twelve drillings for the navigated versus conventional group, respectively (p = 0.021). K-wire trajectory showed an MC orientation in most of the specimen (n = 9, group NP 4, group CP 5). CONCLUSIONS: Image-free navigated coracoclavicular drilling for the repair of acromioclavicular joint dislocation has higher first-pass accuracy in comparison to conventional drill guide-based placement and, therefore, may enable a precise anatomic position of the drill holes and reduce the risk of an iatrogenic coracoid fracture.

Treatment of osteochondral fractures of the knee: a meta-analysis of available scientific evidence.

PURPOSE: Although traumatic osteochondral fractures of the knee represent a common pathology of the knee joint, there is no general agreement concerning specific treatment of this entity. This meta-analysis was initiated in order to evaluate scientific evidence on different treatment options for acute osteochondral fractures of the knee. METHODS: For this purpose an OVID-based systematic literature search was performed including the following databases: MEDLINE, MEDLINE preprints, Embase, CINAHL, Life Science Citations, British National Library of Health and Cochrane Central Register of Controlled Trials. The literature search period was from 1946 to January 2012, which led to the identification of 1,226 articles. After applying study-specific inclusion criteria a total of 19 studies with clinical follow-up of 638 patients were included. The methodology of these studies was systematically analysed by means of the Coleman Methodology Score. Outcome and success rates were evaluated depending on treatment applied. RESULTS: All studies (n = 19) identified represent case series (evidence-based medicine level IV) and included a total of 638 patients. The average post-operative follow-up was 46 ± 27 months (range 3.75-108). The mean number of study subjects per study was 33 ± 44 patients (range 4-169). The average Coleman Methodology Score was 29 ± 17 points (range 5-72). Six different scoring systems were used for clinical assessment. The overall clinical success rate was 83% and varied between 45 and 100%. CONCLUSIONS: This meta-analysis reveals a significant lack of scientific evidence for treatment of osteochondral fractures of the knee. No valid conclusion can be drawn from this study concerning the recommendation of a specific treatment algorithm. Nevertheless, the overall failure rate of 17% underlines that an acute osteochondral fracture of the knee represents an important pathology which is not a self-limiting injury and needs further investigation.

Matrix-associated implantation of predifferentiated mesenchymal stem cells versus articular chondrocytes: in vivo results of cartilage repair after 1 year.

BACKGROUND: The use of predifferentiated mesenchymal stem cells (MSC) leads to better histological results compared with undifferentiated MSC in sheep. This raises the need for a longer term follow-up study and comparison with a clinically established method. HYPOTHESIS: We hypothesized that chondrogenic in vitro predifferentiation of autologous MSC embedded in a collagen I hydrogel leads to better structural repair of a chronic osteochondral defect in an ovine stifle joint after 1 year. We further hypothesized that resulting histological results would be comparable with those of chondrocyte-seeded matrix-associated autologous chondrocyte transplantation (MACT). STUDY DESIGN: Controlled laboratory study. METHODS: Predifferentiation period of ovine MSC within collagen gel in vitro was defined by assessment of several cellular and molecular biological parameters. For the animal study, 2 osteochondral lesions (7-mm diameter) were created at the medial femoral condyles of the hind legs in 9 sheep. Implantation of MSC gels was performed 6 weeks after defect creation. Thirty-six defects were divided into 4 treatment groups: (1) chondrogenically predifferentiated MSC gels (pre-MSC gels), (2) undifferentiated MSC gels (un-MSC gels), (3) MACT gels, and (4) untreated controls (UC). Histological, immunohistochemical, and radiological evaluations followed after 12 months. RESULTS: After 12 months in vivo, pre-MSC gels showed significantly better histological outcome compared with un-MSC gels and UC. Compared with MACT gels, the overall scores were higher for O'Driscoll and International Cartilage Repair Society (ICRS). The repair tissue of the pre-MSC group showed immunohistochemical detection of interzonal collagen type II staining. Radiological evaluation supported superior bonding of pre-MSC gels to perilesional native cartilage. Compared with previous work by our group, no degradation of the repair tissue between 6 and 12 months in vivo, particularly in pre-MSC gels, was observed. CONCLUSION: Repair of chronic osteochondral defects with collagen hydrogels composed of chondrogenically predifferentiated MSC shows no signs of degradation after 1 year in vivo. In addition, pre-MSC gels lead to partially superior histological results compared with articular chondrocytes. CLINICAL RELEVANCE: The results suggest an encouraging method for future treatment of focal osteochondral defects without donor site morbidity by harvesting articular chondrocytes.

Osteoid osteoma of the proximal fibula: an uncommon location with the indication for open surgery.

Purpose. This is a case report of a patient with an osteoid osteoma of the proximal fibula. The objective is to illustrate a rare tumor location that requires open surgery due to closeness of neurological structures. Methods. Clinical and roentgenographic findings, treatment, and histological appearance are presented. Results. Local pain and swelling of the proximal fibula with improvement under salicylates led to the diagnosis of an osteoid osteoma, what was confirmed with an MRI scan. Due to proximity to the common peroneal nerve, we decided for open surgery. During the operation, the nerve was seen to cross the tumor site making it necessary to retract it to expose the entire tumor. Histologically, typical features of osteoid osteoma with a rather well-defined nidus surrounded by sclerotic bone were seen. A complete removal was performed. Conclusion. Osteoid osteomas of the proximal fibula are rare. When planning surgery, the common peroneal nerve must be identified, and its further distal course should be taken into account to avoid iatrogenic damage to the nerve.

Repair of chronic osteochondral defects using predifferentiated mesenchymal stem cells in an ovine model.

BACKGROUND: The use of mesenchymal stem cells (MSCs) to treat osteochondral defects caused by sports injuries or disease is of particular interest. However, there is a lack of studies in large-animal models examining the benefits of chondrogenic predifferentiation in vitro for repair of chronic osteochondral defects. HYPOTHESIS: Chondrogenic in vitro predifferentiation of autologous MSCs embedded in a collagen I hydrogel currently in clinical trial use for matrix-associated autologous chondrocyte transplantation facilitates the regeneration of a chronic osteochondral defect in an ovine stifle joint. STUDY DESIGN: Controlled laboratory study. METHODS: The optimal predifferentiation period of ovine MSCs within the type I collagen hydrogel in vitro was defined by assessment of several cellular and molecular biological parameters. For the animal study, osteochondral lesions (diameter 7 mm) were created at the medial femoral condyles of the hind legs in 10 merino sheep. To achieve a chronic defect model, implantation of the ovine MSCs/hydrogel constructs was not performed until 6 weeks after defect creation. The 40 defects were divided into 4 treatment groups: (1) chondrogenically predifferentiated ovine MSC/hydrogel constructs (preMSC-gels), (2) undifferentiated ovine MSC/hydrogel constructs (unMSC-gels), (3) cell-free collagen hydrogels (CF-gels), and (4) untreated controls (UCs). Evaluation followed after 6 months. RESULTS: With regard to proteoglycan content, cell count, gel contraction, apoptosis, compressive properties, and progress of chondrogenic differentiation, a differentiation period of 14 days in vitro was considered optimal. After 6 months in vivo, the defects treated with preMSC-gels showed significantly better histologic scores with morphologic characteristics of hyaline cartilage such as columnarization and presence of collagen type II. CONCLUSION: Matrix-associated autologous chondrocyte transplantation with predifferentiated MSCs may be a promising approach for repair of focal, chronic osteochondral defects. CLINICAL RELEVANCE: The results suggest an encouraging method for future treatment of focal osteochondral defects to prevent progression to osteoarthritis.

Bone quality measured by the radiogrammetric parameter "cortical index" and reoperations after locking plate osteosynthesis in patients sustaining proximal humerus fractures.

AIM: To analyse the radiogrammetric parameter "cortical index" (CI) and its predictive value for proximal humerus fractures. Furthermore, to investigate the reoperations and the cause of reoperations after locking plate osteosynthesis of displaced proximal humerus fractures. PATIENTS AND METHODS: 113 consecutive patients (73 women and 40 men) with a median age of 66 years (range 18-100 years) were included in this study. The median follow-up time in our database was 4.7 years (range 45-72 months). For a comparative matched-group analysis of the CI, patients with a fall on the shoulder without fracture were selected. Demographic data and all reoperations were recorded after median 58 months postoperatively. The CI was measured at the proximal humeral diaphysis. RESULTS: The CI showed to be significant lower in the fracture group (mean 0.28) when compared to the matched group (mean 0.47, p < 0.01). 39% patients underwent a reoperation within 40 months postoperatively. 24% were reoperated within the first 12 months postoperatively, and 15% were reoperated after 12 months or later. The reoperation was independent of bone quality (p = 0.85). CONCLUSIONS: The risk for reoperation is independent of the CI even though the CI may be a predictor for proximal humerus fracture. Younger patients should be aware that surgical treatment of proximal humerus fractures might be a two-stage surgery. Regular follow-up visits for older patients during the first postoperative year must be assured.

Biomechanical evaluation of knotless anatomical double-layer double-row rotator cuff repair: a comparative ex vivo study.

BACKGROUND: The layered configuration of the rotator cuff tendon is not taken into account in classic rotator cuff tendon repair techniques. HYPOTHESIS: The mechanical properties of (1) the classic double-row technique, (2) a double-layer double-row (DLDR) technique in simple suture configuration, and (3) a DLDR technique in mattress suture configuration are significantly different. STUDY DESIGN: Controlled laboratory study. METHODS: Twenty-four sheep shoulders were assigned to 3 repair groups of full-thickness infraspinatus tears: group 1, traditional double-row repair; group 2, DLDR anchor repair with simple suture configuration; and group 3, DLDR knotless repair with mattress suture configuration. After ultrasound evaluation of the repair, each specimen was cyclically loaded with 10 to 100 N for 50 cycles. Each specimen was then loaded to failure at a rate of 1 mm/s. RESULTS: There were no statistically significant differences among the 3 testing groups for the mean footprint area. The cyclic loading test revealed no significant difference among the 3 groups with regard to elongation. For the load-to-failure test, groups 2 and 3 showed no differences in ultimate tensile load when compared with group 1. However, when compared to group 2, group 3 was found to have significantly higher values regarding ultimate load, ultimate elongation, and energy absorbed. CONCLUSION: The DLDR fixation techniques may provide strength of initial repair comparable with that of commonly used double-row techniques. When compared with the knotless technique with mattress sutures, simple suture configuration of DLDR repair may be too weak. Knotless DLDR rotator cuff repair may (1) restore the footprint by the use of double-row principles and (2) enable restoration of the shape and profile. CLINICAL RELEVANCE: Double-layer double-row fixation in mattress suture configuration has initial fixation strength comparable with that of the classic double-row fixation and so may potentially improve functional results of rotator cuff repair.

Knotless anatomic double-layer double-row rotator cuff repair: a novel technique re-establishing footprint and shape of full-thickness tears.

The standard technique for restoring footprint after full-thickness tears of the rotator cuff includes double-row or transosseous-equivalent techniques. However, the anatomically typical bird's beak shape and profile of tendon insertion may not be originally restored and biomechanics may be altered. In this report, the authors describe a technique that involves creating two intratendinous stitches at different levels of the torn tendon. The first passes through the bursal-side layer, the second stitch through the joint-side layer. Both stitches may be performed in mattress suture configuration. The anchorage is performed by knotless anchors in order to avoid knots lying within the insertion area. The footprint is restored first medially then laterally by the use of double-row principles. The joint-side suture is anchored within the medially placed anchor. The bursal-side suture is anchored by a laterally placed anchor. The anatomic insertion and restoration of the shape and profile may be enabled by the described double-layer suture technique. Using a double-layer double-row repair may potentially improve functional results of rotator cuff repair constructs.

Infiltration of the pes anserinus complex by an extraarticular diffuse-type giant cell tumor (D-TGCT).

This report describes the case of a 26-year-old woman with a recurrent extraarticular diffuse-type tenosynovial giant cell tumor (D-TGCT) of the medial region of the knee affecting the pes anserinus and hamstring tendons. Presurgical MRI did not exclude infiltrative properties of the tumor. In the histological evaluation, the tumor showed an aggressive dispersion by infiltrating the collagenous tissue of the hamstring tendons. The treatment included a resection of the pes anserinus complex with distal semitendinosus and gracilis tendons. Regarding extraarticular D-TGCT a review of the literature showed a predominant affection of the medial region of the knee and thigh.

The use of hamstrings in anterior cruciate ligament reconstruction in patients over 40 years.

INTRODUCTION: Anterior cruciate ligament reconstruction is an increasingly established method even in patients over 40 years old. Recent studies with regard to this procedure used BTB transplants. We did a retrospective follow-up examination on over-40-year-old patients with anterior cruciate ligament reconstruction using hamstring transplants and compared them to a younger control group. Our hypothesis is that functional outcome after ACL-reconstruction is comparable in patients under and over 40 years of age. MATERIALS AND METHODS: Retrospective follow-up examinations in 28 patients, 11 women and 17 men. The average age at the time of operation was 43.5 years (range 40-61). The average follow-up period was 30.4 months. Half of the patients had a femoral fixation in TransFix technique (Arthrex, Naples, USA), while the other 14 patients had a femoral bioscrew fixation (Arthrex, Naples, USA). Objectivity was ensured by measurements of anterior tibial translation with the rolimeter (Aircast). The functional outcome was determined by clinical scores (Tegner activity scale, Lysholm knee score, OAK score and IKDC score). The degree of arthrosis was defined on the basis of tunnelview radiographs and compared to the non-operated site. Functional results and degree of laxity was compared to a sex matched control group (mean age 28.0). RESULTS: The median values for the Lysholm knee score were 91.5 points (range 69-100), for the OAK score 93.5 points (range 67-100) and for the IKDC score 83.35 points (range 62.1-100). For the Tegner activity scale values of 4.5 points (range 3-8) were obtained. In the IKDC knee examination form we found normal and nearly normal values in 86% and in the OAK examination score good and very good results in 82%. Ninety-three percent had an AP side-to-side difference of <5 mm in the operated knee. Subjectively, 75% reported that they had no feeling of instability, even when practising sport. No significant correlation between functional outcome and patients' age was present. Furthermore there were no significant differences between the investigated and the younger control group. The most advanced signs of arthrosis were found in the medial compartment of the operated side (degree A: 36%; degree B: 46%; degree C: 14%; degree D: 4%). CONCLUSION: The predominantly good results and a high level of patient satisfaction show that anterior cruciate ligament reconstruction is justified even in over-40-year-old patients with persistend subjective symptomatic anterior knee instability. The indication for reconstruction should be based on individual factors such as level of activity or subjective feeling of instability rather than on a dogmatic age limit. Advanced arthrotic changes compared to the healthy side, might be due to a too long period of preoperative decision making.