No evidence for combining cartilage treatment and knee osteotomy in osteoarthritic joints: a systematic literature review.

PURPOSE: To assess whether the combination of HTO and cartilage treatment produced an additional clinical benefit compared to HTO alone. The secondary aim was to identify if there was any difference among different cartilage procedures in terms of healing potential and clinical outcome. METHODS: A systematic review of the literature was performed on PubMed database by three independent observers according to the following inclusion criteria: clinical reports of any level of evidence, written in the English language, with no time limitation, about HTO associated with cartilage surgical and injective treatment, including surveys reporting clinical, radiological, or second-look outcomes at any follow-up time. RESULTS: The database search identified 1956 records: 21 studies were included for the final analysis, for a total of 1068 patients; 10 case series and 11 comparative studies. While overall good results were reported in the case series, the analysis of the comparative studies showed less uniform results. Among the eight studies investigating HTO with cartilage surgical procedures, improved tissue regeneration was found in 5/8 studies, whereas a clinical improvement was reported only in two studies. Three studies on HTO combination with injective treatment showed better tissue regeneration and clinical benefit. CONCLUSIONS: Literature presents low-quality studies, with only few heterogeneous comparative papers. While surgical treatments targeting only the cartilage layer did not achieve clinical improvements, injective treatments targeting the overall joint environment showed promising findings. This prompts further research towards the development of treatments able to improve knee osteotomies outcomes. However, until new evidence will prove otherwise, there is no indication for a combined cartilage treatment in routine clinical practice. LEVEL OF EVIDENCE: Level IV.

Musculoskeletal tissues-on-a-chip: role of natural polymers in reproducing tissue-specific microenvironments.

Over the past years, 3Din vitromodels have been widely employed in the regenerative medicine field. Among them, organ-on-a-chip technology has the potential to elucidate cellular mechanism exploiting multichannel microfluidic devices to establish 3D co-culture systems that offer control over the cellular, physico-chemical and biochemical microenvironments. To deliver the most relevant cues to cells, it is of paramount importance to select the most appropriate matrix for mimicking the extracellular matrix of the native tissue. Natural polymers-based hydrogels are the elected candidates for reproducing tissue-specific microenvironments in musculoskeletal tissue-on-a-chip models owning to their interesting and peculiar physico-chemical, mechanical and biological properties. Despite these advantages, there is still a gap between the biomaterials complexity in conventional tissue engineering and the application of these biomaterials in 3Din vitromicrofluidic models. In this review, the aim is to suggest the adoption of more suitable biomaterials, alternative crosslinking strategies and tissue engineered-inspired approaches in organ-on-a-chip to better mimic the complexity of physiological musculoskeletal tissues. Accordingly, after giving an overview of the musculoskeletal tissue compositions, the properties of the main natural polymers employed in microfluidic systems are investigated, together with the main musculoskeletal tissues-on-a-chip devices.

Culture of 3D bioprinted bone constructs requires an increased fluid dynamic stimulation.

In vitro flow-induced mechanical stimulation of developing bone tissue constructs has been shown to favor mineral deposition in scaffolds seeded with cells directly exposed to the fluid flow. However, the effect of fluid dynamic parameters, such as shear stress (SS), within 3D bioprinted constructs is still unclear. Thus, this study aimed at correlating the SS levels and the mineral deposition in 3D bioprinted constructs, evaluating the possible dampening effect of the hydrogel. Human mesenchymal stem cells (hMSCs) were embedded in 3D bioprinted porous structures made of alginate and gelatin. 3D bioprinted constructs were cultured in an osteogenic medium assessing the influence of different flow rates (0, 0.7 and 7 ml/min) on calcium and collagen deposition through histology, and bone volume (BV) through micro-computed tomography. Uniform distribution of calcium and collagen was observed in all groups. Nevertheless, BV significantly increased in perfused groups as compared to static control, ranging from 0.35±0.28 mm3, 11.90±8.74 mm3 and 25.81±5.02 mm3 at week 3 to 2.28±0.78 mm3, 22.55±2.45 mm3 and 46.05±5.95 mm3 at week 6 in static, 0.7 and 7 ml/min groups, respectively. SS values on construct fibers in the range 10-100 mPa in 7 ml/min samples were twice as high as those in 0.7 ml/min samples showing the same trend of BV. The obtained results suggest that it is necessary to enhance the flow-induced mechanical stimulation of cell-embedding hydrogels to increase the amount of mineral deposited by hMSCs, compared to what is generally reported for the development of in vitro bone constructs. STATEMENT OF SIGNIFICANCE: In this study, we evaluated for the first time how the hydrogel structure dampens the effect of flow-induced mechanical stimulation during the culture of 3D bioprinted bone tissue constructs. By combining computational and experimental techniques we demonstrated that those shear stress thresholds generally considered for culturing cells seeded on scaffold surface, are no longer applicable when cells are embedded in 3D bioprinted constructs. Significantly, more bone volume was formed in constructs exposed to shear stress values generally considered as detrimental than in constructs exposed shear stress values generally considered as beneficial after 3 weeks and 6 weeks of dynamic culture using a perfusion bioreactor.

Are ankle chondrocytes from damaged fragments a suitable cell source for cartilage repair?

OBJECTIVE: To characterize the post-expansion cartilage-forming capacity of chondrocytes harvested from detached fragments of osteochondral lesions (OCLs) of ankle joints (Damaged Ankle Cartilage Fragments, DACF), with normal ankle cartilage (NAC) as control. DESIGN: DACF were obtained from six patients (mean age: 35 years) with symptomatic OCLs of the talus, while NAC were from 10 autopsies (mean age: 55 years). Isolated chondrocytes were expanded for two passages and then cultured in pellets for 14 days or onto HYAFF-11 meshes (FAB, Italy) for up to 28 days. Resulting tissues were assessed histologically, biochemically [glycosaminoglycan (GAG), DNA and type II collagen (CII)] and biomechanically. RESULTS: As compared to NAC, DACF contained significantly lower amounts of DNA (3.0-fold), GAG (5.3-fold) and CII (1.5-fold) and higher amounts of type I collagen (6.2-fold). Following 14 days of culture in pellets, DACF-chondrocytes generated tissues less intensely stained for Safranin-O and CII, with significantly lower GAG contents (2.8-fold). After 28 days of culture onto HYAFF((R))-11, tissues generated by DACF-chondrocytes were less intensely stained for Safranin-O and CII, contained significantly lower amounts of GAG (1.9-fold) and CII (1.4-fold) and had lower equilibrium (1.7-fold) and dynamic pulsatile modulus (3.3-fold) than NAC-chondrocytes. CONCLUSION: We demonstrated that DACF-chondrocytes have inferior cartilage-forming capacity as compared to NAC-chondrocytes, possibly resulting from environmental changes associated with trauma/disease. The study opens some reservations on the use of DACF-derived cells for the repair of ankle cartilage defects, especially in the context of tissue engineering-based approaches.

Intra-individual comparison of human ankle and knee chondrocytes in vitro: relevance for talar cartilage repair.

OBJECTIVE: As compared to knee chondrocytes (KC), talar chondrocytes (TC) have superior synthetic activity and increased resistance to catabolic stimuli. We investigated whether these properties are maintained after TC are isolated and expanded in vitro. METHODS: Human TC and KC from 10 cadavers were expanded in monolayer and then cultured in pellets for 3 and 14 days or in hyaluronan meshes (Hyaff-11) for 14 and 28 days. Resulting tissues were assessed biochemically, histologically, biomechanically and by real-time reverse transcriptase-polymerase chain reaction (RT-PCR). The proteoglycan and collagen synthesis rates in the pellets were also measured following exposure to Interleukin-1 beta (IL-1 beta). RESULTS: After 14 days of pellet culture, TC and KC expressed similar levels of type I collagen (CI) and type II collagen (CII) mRNA and the resulting tissues contained comparable amounts of glycosaminoglycans (GAG) and displayed similar staining intensities for CII. Also proteoglycan and collagen synthesis were similar in TC and KC pellets, and dropped to a comparable extent in response to IL-1 beta. Following 14 days of culture in Hyaff-11, TC and KC generated tissues with similar amounts of GAG and CI and CII. After 28 days, KC deposited significantly larger fractions of GAG and CII than TC, although the trend was not reflected in the measured biomechanical properties. CONCLUSION: After isolation from their original matrices and culture expansion, TC and KC displayed similar biosynthetic activities, even in the presence of catabolic stimuli. These in vitro data suggest a possible equivalence of TC and KC as autologous cell sources for the repair of talar cartilage lesions.

A novel implantation technique for engineered osteo-chondral grafts.

We present a novel method to support precise insertion of engineered osteochondral grafts by pulling from the bone layer, thereby minimizing iatrogenic damage associated with direct manipulation of the cartilage layer. Grafts were generated by culturing human expanded chondrocytes on Hyaff-11 meshes, sutured to Tutobone spongiosa cylinders. Through the bone layer, shaped to imitate the surface-contours of the talar dome, two sutures were applied: the first for anterograde implantation, to pull the graft into the defect, and the second for retrograde correction, in case of a too deep insertion. All grafts could be correctly positioned into osteochondral lesions created in cadaveric ankle joints with good fit to the surrounding cartilage. Implants withstood short-term dynamic stability tests applied to the ankle joint, without delamination or macroscopic damage. The developed technique, by allowing precise and stable positioning of osteochondral grafts without iatrogenic cartilage damage, is essential for the implantation of engineered tissues, where the cartilage layer is not fully mechanically developed, and could be considered also for conventional autologous osteochondral transplantation.

Traumatic bilateral medial patellar instability in a 15-year-old girl.

Introduction: Patellar dislocation encompasses the 2-3% of the knee joint injuries, and lateral patellar luxation is by far more common than the medial one. Medial patellar dislocation is described only by few reports and generally as a consequence of previous surgeries. The purpose of this case report is to describe the surgical management of a rare case of traumatic bilateral medial patellar dislocation in a 15-year-old girl with no previous patellofemoral surgeries. Case Report: The patient underwent a traumatic medial patellar dislocation on the left knee, and 18 months later also on the right one. In both cases, the first proposed treatment was a conservative therapy, encompassing the use of a brace and muscular imbalance correction. After a 6-month period, the patient still referred to the persistent sensation of "giving away," so surgery was advised. The surgical operation consisted of an open medial retinacular release with complete dissection of the hypertrophic medial patellofemoral ligament and a transfer of the vastus medialis oblique to the superior border of the patella. Seven years after surgery, the patient declared to be satisfied with the procedure, referring only slight difficulty in squatting, jumping, and running. So far, no further episodes of dislocation occurred. Conclusions: The present case report showed the favorable result of surgical correction of a unique case of bilateral non-iatrogenic medial patellar luxation, in the absence of any underlying bony-structural abnormality. No other papers dealing with medial traumatic bilateral patellar dislocation are found in current literature.

A low percentage of autologous serum can replace bovine serum to engineer human nasal cartilage.

For the generation of cell-based therapeutic products, it would be preferable to avoid the use of animal-derived components. Our study thus aimed at investigating the possibility to replace foetal bovine serum (FBS) with autologous serum (AS) for the engineering of cartilage grafts using expanded human nasal chondrocytes (HNC). HNC isolated from 7 donors were expanded in medium containing 10% FBS or AS at different concentrations (2%, 5% and 10%) and cultured in pellets using serum-free medium or in Hyaff(R)-11 meshes using medium containing FBS or AS. Tissue forming capacity was assessed histologically (Safranin O), immunohistochemically (type II collagen) and biochemically (glycosaminoglycans -GAG- and DNA). Differences among experimental groups were assessed by Mann Whitney tests. HNC expanded under the different serum conditions proliferated at comparable rates and generated cartilaginous pellets with similar histological appearance and amounts of GAG. Tissues generated by HNC from different donors cultured in Hyaff(R)-11 had variable quality, but the accumulated GAG amounts were comparable among the different serum conditions. Staining intensity for collagen type II was consistent with GAG deposition. Among the different serum conditions tested, the use of 2% AS resulted in the lowest variability in the GAG contents of generated tissues. In conclusion, a low percentage of AS can replace FBS both during the expansion and differentiation of HNC and reduce the variability in the quality of the resulting engineered cartilage tissues.

Cartilage tissue engineering using pre-aggregated human articular chondrocytes.

In this study, we first aimed at determining whether human articular chondrocytes (HAC) proliferate in aggregates in the presence of strong chondrocyte mitogens. We then investigated if the aggregated cells have an enhanced chondrogenic capacity as compared to cells cultured in monolayer. HAC from four donors were cultured in tissue culture dishes either untreated or coated with 1% agarose in the presence of TGFbeta-1, FGF-2 and PDGF-BB. Proliferation and stage of differentiation were assessed by measuring respectively DNA contents and type II collagen mRNA. Expanded cells were induced to differentiate in pellets or in Hyaff-11 meshes and the formed tissues were analysed biochemically for glycosaminoglycans (GAG) and DNA, and histologically by Safranin O staining. The amount of DNA in aggregate cultures increased significantly from day 2 to day 6 (by 3.2-fold), but did not further increase with additional culture time. Expression of type II collagen mRNA was about two orders of magnitude higher in aggregated HAC as compared to monolayer expanded cells. Pellets generated by aggregated HAC were generally more intensely stained for GAG than those generated by monolayer-expanded cells. Scaffolds seeded with aggregates accumulated more GAG (1.3-fold) than scaffolds seeded with monolayer expanded HAC. In conclusion, this study showed that HAC culture in aggregates does not support a relevant degree of expansion. However, aggregation of expanded HAC prior to loading into a porous scaffold enhances the quality of the resulting tissues and could thus be introduced as an intermediate culture phase in the manufacture of engineered cartilage grafts.

An algorithm to avoid missed open-book pelvic fractures.

OBJECTIVE: In polytrauma patients, to limit the pelvic space favouring internal bleeding, the use of pelvic binders is now a standard practice. In case of external pelvic binder placement with anatomic reduction of the symphyseal and sacroiliac joints, delayed diagnosis and missed injuries could occur. The aim of this study is to document the risk of missed diagnosis, as well as to identify a possible algorithm for optimal management of traumatized patients with pelvic binders, in order to reach an early diagnosis of pelvic fractures without additional risks. CASE REPORT: We report three cases of open-book pelvic fractures that were initially missed. The external pelvic binders applied had adequately reduced the fractures. The computed tomography on arrival excluded a diastasis of the symphysis pubis. On removal of the pelvic binder and repetition of the radiological imaging, the fractures were evidenced. CONCLUSIONS: We have accordingly created an algorithm for polytrauma patients to determine when the pelvic binder should be released before radiological imaging and when repeated radiological imaging should be done. The use of this algorithm in trauma centers will help to reduce the number of missed injuries, and the number of late diagnoses as well as will increase the patient survival rates.

Tackling muscle fibrosis: From molecular mechanisms to next generation engineered models to predict drug delivery.

Muscle fibrosis represents the end stage consequence of different diseases, among which muscular dystrophies, leading to severe impairment of muscle functions. Muscle fibrosis involves the production of several growth factors, cytokines and proteolytic enzymes and is strictly associated to inflammatory processes. Moreover, fibrosis causes profound changes in tissue properties, including increased stiffness and density, lower pH and oxygenation. Up to now, there is no therapeutic approach able to counteract the fibrotic process and treatments directed against muscle pathologies are severely impaired by the harsh conditions of the fibrotic environment. The design of new therapeutics thus need innovative tools mimicking the obstacles posed by the fibrotic environment to their delivery. This review will critically discuss the role of in vivo and 3D in vitro models in this context and the characteristics that an ideal model should possess to help the translation from bench to bedside of new candidate anti-fibrotic agents.

Engineered cartilage generated by nasal chondrocytes is responsive to physical forces resembling joint loading.

OBJECTIVE: To determine whether engineered cartilage generated by nasal chondrocytes (ECN) is responsive to different regimens of loading associated with joint kinematics and previously shown to be stimulatory of engineered cartilage generated by articular chondrocytes (ECA). METHODS: Human nasal and articular chondrocytes, harvested from 5 individuals, were expanded and cultured for 2 weeks into porous polymeric scaffolds. The resulting ECN and ECA were then maintained under static conditions or exposed to the following loading regimens: regimen 1, single application of cyclic deformation for 30 minutes; regimen 2, intermittent application of cyclic deformation for a total of 10 days, followed by static culture for 2 weeks; regimen 3, application of surface motion for a total of 10 days. RESULTS: Prior to loading, ECN constructs contained significantly higher amounts of glycosaminoglycan (GAG) and type II collagen compared with ECA constructs. ECN responded to regimen 1 by increasing collagen and proteoglycan synthesis, to regimen 2 by increasing the accumulation of GAG and type II collagen as well as the dynamic modulus, and to regimen 3 by increasing the expression of superficial zone protein, at the messenger RNA level and the protein level, as well as the release of hyaluronan. ECA constructs were overall less responsive to all loading regimens, likely due to the lower extracellular matrix content. CONCLUSION: Human ECN is responsive to physical forces resembling joint loading and can up-regulate molecules typically involved in joint lubrication. These findings should prompt future in vivo studies exploring the possibility of using nasal chondrocytes as a cell source for articular cartilage repair.

[Merkel cell carcinoma. Retrospective analysis of 4 cases with special reference to diagnosis, therapy and long-term outcome]. / Das Merkelzellkarzinom. Retrospektive Analyse von vier Fällen unter spezieller Berücksichtigung der Diagnostik, der Therapie und des Langzeitverlaufes.

BACKGROUND: Merkel cell carcinoma is an aggressive neuro-endocrine skin tumor with early regional lymph node involvement and early distant metastases. Diagnostic work-up may be difficult because of the low incidence of the tumor. Treatment concepts are individual and long-term-outcome are varying markedly. METHODS: Retrospective analyse of four cases with special regard to the diagnostic, therapeutic approach and the long-term follow-up. RESULTS: In every case diagnosis has only been made histologically. In the first patient, suffering from a tumor on the upper arm, after the tumor removal, local and axillary radiotherapy has been performed. In a second case with an extended tumor on the shank, a palliative tumor-debulking was followed by a chemo- and radiotherapy. The third Patient had a tumor in the gluteal region with involvement of the regional lymph nodes. He was treated by a complete surgical excision and lymphadenectomy followed by a local radiotherapy with subsequent chemotherapy. The fourth patient with tumor on the elbow, without lymph node involvement, refused surgical intervention, therefore she has been treated by radio- and chemotherapy. All patients are respectively 1.2 and 3 years are alive without evidence of recurrence. One patient died after 1.5 year because of tumor relapse. CONCLUSION: Diagnosis of Merkel cell carcinoma is difficult and is established only by in- or excision biopsy of the tumor. If ever possible surgical excision combined with regional lymphadenectomy should be performed. Adjuvant radiotherapy is established, whereas the value of chemotherapy has not yet be defined and might be beneficial only in cases of expansive or disseminated growth. In our series we did encounter the often described metastatic involvement of other organs just in one case.

[Bilateral popliteal artery entrapment syndrome. Is preventive operation on the asymptomatic side indicated?]. / Das bilaterale arterielle popliteale Entrapmentsyndrom. Ist die präventive Operation der asymptomatischen Gegenseite indiziert?

Popliteal artery entrapment is a rare cause of claudication symptoms, but should always be included in the differential diagnosis of lower limb ischaemia in young patients, especially men. On an embryological basis, PAES is the result of the abnormal development of the popliteal artery or the gastrocnemius muscle. The anomaly is manifested as one of four types. Untreated, the entrapment results in the deterioration of the artery, resulting in eventual occlusion. Presenting the case of a 37 year old female patient with bilateral PAES and a review of the literature we discuss the clinical findings, diagnosis, treatment options and the management of the often asymptomatic opposite side.

[Endoscopic bursa shaving in acute bursitis]. / Das endoskopische Bursashaving bei akuter Bursitis.

OBJECTIVES: After resection of olecranon or prepatellar bursa for bursitis there can be long-term skin complications in up to 20%. We wanted to determine the outcome after endoscopic resection, a technique first described in 1990. METHODS: In a period of three years (6/97-7/00) 13 Patients with bursitis were prospectively enclosed in the study and underwent endoscopic resection of the bursa. All patients were examined clinically three weeks and six months postoperatively. RESULTS: In nine patients a resection of the Olecranon bursa was performed, in four patients of the pre-patellar bursa. 11 cases showed a septic bursitis, two a chronic. 50% of the operations were conducted in general anesthesia. We observed no intra- or postoperative complications. The follow-up examinations showed no pain, no recurrence and no loss of joint motion. CONCLUSION: It is our opinion that the endoscopic resection of the Olecranon and pre-patellar bursa for septic bursitis is a promising technique and shows favourable results compared to the open resection.